Science.gov

Sample records for blue nile river

  1. Age and origin of the Gezira alluvial fan between the Blue and White Nile rivers

    NASA Astrophysics Data System (ADS)

    Williams, martin

    2014-05-01

    The Gezira is a low-angle alluvial fan bounded by the Blue Nile to the east and the White Nile to the west. It is the main agricultural region of Sudan and produces high quality long-staple cotton for export. Dark cracking clays (vertisols) cover much of the Gezira and range in age from 50 kyr to Holocene. The Gezira is traversed by a series of defunct sandy channels that originate between Sennar and Wad Medani on the present-day Blue Nile. With a radius of 300 km and an area of 40,000 km2 the Gezira is a mega-fan. The younger channels range in age from early Holocene to 100 kyr, while near surface channels filled with rolled quartz and carbonate gravels have ages back to >250 kyr. Boreholes in the Gezira reveal coarse alluvial sands and gravels in now buried channels overlain by alluvial clays, forming a repetitive sequence of fining-upwards alluvial units. that probably extend back to Pliocene times. The fan is up to 180 m thick with a volume of ~1,800 km3. The sandy or gravelly bed-load channels coincide with colder drier climates and sparse vegetation in the Ethiopian headwaters of the Blue Nile and the alluvial clays denote widespread flooding during times of stronger summer monsoon. The early stages of such flood events were often accompanied by mass burial of Nile oyster (Etheria elliptica) beds, such as the 45-50 kyr floods that deposited up to 5 m of clay in the northern Gezira. A unique feature of the eastern Gezira is a former Blue Nile channel at least 80 km long running parallel to the present river and entirely filled with volcanic ash. The channel was only 3-4 m deep and 20-30 m wide. Very fine laminations and cross-beds, together with locally abundant phytoliths and sponge spicules, suggest slow-moving water, with flow dispersed across many distributary channels. The ash geochemistry is similar to that in the lower part of the Kibish Formation in the lower Omo valley of southern Ethiopia and points to a minimum age of 100 kyr and a maximum age of

  2. Using ENSO Indices to Enhance Long-Range Ensemble Streamflow Forecasts in The Blue Nile River

    NASA Astrophysics Data System (ADS)

    Habib, M. A.; Bradley, A.

    2012-12-01

    River forecasting centers around the globe have been using hydrologic ensemble forecast systems operationally. Better-enhanced forecasting systems are the ultimate need of the decision maker. This study proposes an enhancement technique for Long-Range Ensemble Streamflow Forecasts in The Blue Nile River. Many studies showed the link between summer rainfall and the large scale climate oscillations. Strong correlation is found between the El-Nino Southern Oscillations (ENSO) and annual flows in the Nile River at Diem on the Sudanese-Ethiopian boarders. Long-range streamflow forecasts produced by The Nile Forecast System at Ministry of Public Works and Irrigation in Egypt are used. Traditionally, baseline forecast weights each trace of the ensemble equally. In this study, we add an enhancement process to the forecasts by changing their weights depending on the correlation between the Streamflow and the ENSO indices (e.g. SST3.4, SOI). Weighting techniques using different distributions of the ENSO indices (e.g. Kernel, Gaussian) are examined. Diagnostic verification measures are used to evaluate this enhancement process.

  3. Morphological changes of Gumara River channel over 50 years, upper Blue Nile basin, Ethiopia

    NASA Astrophysics Data System (ADS)

    Abate, Mengiste; Nyssen, Jan; Steenhuis, Tammo S.; Moges, Michael M.; Tilahun, Seifu A.; Enku, Temesgen; Adgo, Enyew

    2015-06-01

    In response to anthropogenic disturbances, alluvial rivers adjust their geometry. The alluvial river channels in the upper Blue Nile basin have been disturbed by human-induced factors since a longtime. This paper examines channel adjustment along a 38-km stretch of the Gumara River which drains towards Lake Tana and then to the Blue Nile. Over a 50 years period, agriculture developed rapidly in the catchment and flooding of the alluvial plain has become more frequent in recent times. The objectives of this study were to document the changes in channel planform and cross-section of the Gumara River and to investigate whether the changes could have contributed to the frequent flooding or vice versa. Two sets of aerial photographs (1957 and 1980) were scanned, and then orthorectified. Recent channel planform information was extracted from SPOT images of 2006 and Google Earth. Channel planform and bed morphology (vertical changes) were determined for these nearly 50 years period. The vertical changes were determined based on aggradation along a permanent structure, historic information on river cross-sections at a hydrological gauging station, and field observations. The results indicate that the lower reach of Gumara near its mouth has undergone major planform changes. A delta with approx. 1.12 km2 of emerged land was created between 1957 and 1980 and an additional 1 km2 of land has been added between 1980 and 2006. The sinuosity of the river changed only slightly: negatively (-1.1% i.e. meandering decreased) for the period from 1957 to 1980 and positively (+3.0%) for the period 1980-2006. Comparison of cross-sections at the hydrological gauging station showed that the deepest point in the river bed aggraded by 2.91 m for the period 1963-2009. The importance of sediment deposition in the stream and on its banks is related to land degradation in the upper catchment, and to artificial rising of Lake Tana level that creates a backwater effect and sediment deposition in

  4. Predictability of current and future multi-river discharges: Ganges, Brahmaputra, Yangtze, Blue Nile, and Murray-Darling rivers

    NASA Astrophysics Data System (ADS)

    Jian, Jun

    2007-12-01

    Determining river discharge is of critical importance to many societies as they struggle with fresh water supply and risk of flooding. In Bangladesh, floods occur almost every year but with sufficient irregularity to have adverse social and economical consequences. Important goals are to predict the discharge to be used for the optimization of agricultural practices, disaster mitigation and water resource management. The aim of this study is to determine the predictability of river discharge in a number of major rivers on time scale varying from weeks to a century. We investigated predictability considering relationship between SST and discharge. Next, we consider IPCC model projections of river discharge while the models are statistically adjusted against observed discharges. In this study, we consider five rivers, the Ganges, the Brahmaputra, the Yangtze, the Blue Nile, and the Murray-Darling Rivers. On seasonal time scales, statistically significant correlations are found between mean monthly equatorial Pacific sea surface temperature (SST) and the summer Ganges discharge with lead times of 2-3 months due to oscillations of the El Nino-Southern Oscillation (ENSO) phenomena. In addition, there are strong correlations in the southwest and northeast Pacific. These, too, appear to be tied to the ENSO cycle. The Brahmaputra discharge, on the other hand, shows somewhat weaker relationships with tropical SST. Strong lagged correlations relationships are found with SST in the Bay of Bengal but these are the result of very warm SSTs and exceptional Brahmaputra discharge during the summer of 1998. When this year is removed from the time series, relationships weaken everywhere except in the northwestern Pacific for the June discharge and in areas of the central Pacific straddling the equator for the July discharge. The relationships are relative strong, but they are persistent from month to month and suggest that two different and sequential factors influence Brahmaputra

  5. Effects of Bahir Dar Textile Factory Effluents on the Water Quality of the Head Waters of Blue Nile River, Ethiopia.

    PubMed

    Mehari, Abrehet Kahsay; Gebremedhin, Shewit; Ayele, Belayneh

    2015-01-01

    The study was conducted in 2013/14 with the objective of determining the effects of Bahir Dar textile factory effluents on the head of Blue Nile River water quality. Dissolve oxygen was higher at the upstream site of the river, whereas BOD5, TDS, and total alkalinity values were higher at wastewater outlet of the factory site. The mean values of dissolved oxygen, BOD5, and total alkalinity were above maximum permissible limits set by WHO for drinking water at head of Blue Nile River. The mean value of BOD5 was above permissible limit of IFC for textile effluents to be discharged to surface water. A total of 836 aquatic macroinvertebrate individuals belonging to 21 families were collected. The Shannon-Wiener Diversity Index, the Hilsenhoff family-level biotic index, family richness, and percent dipterans were calculated. Hilsenhoff family-level biotic index and percent dipterans metrics differed significantly among sampling sites (P < 0.05). Hilsenhoff family-level biotic index was higher at the most downstream site but percent dipterans were higher at site of discharge of effluent to the head of Blue Nile River. Therefore, there is indication that effluent demands frequent control and proper treatment before being discharged to the environment.

  6. Effects of Bahir Dar Textile Factory Effluents on the Water Quality of the Head Waters of Blue Nile River, Ethiopia

    PubMed Central

    Mehari, Abrehet Kahsay; Gebremedhin, Shewit; Ayele, Belayneh

    2015-01-01

    The study was conducted in 2013/14 with the objective of determining the effects of Bahir Dar textile factory effluents on the head of Blue Nile River water quality. Dissolve oxygen was higher at the upstream site of the river, whereas BOD5, TDS, and total alkalinity values were higher at wastewater outlet of the factory site. The mean values of dissolved oxygen, BOD5, and total alkalinity were above maximum permissible limits set by WHO for drinking water at head of Blue Nile River. The mean value of BOD5 was above permissible limit of IFC for textile effluents to be discharged to surface water. A total of 836 aquatic macroinvertebrate individuals belonging to 21 families were collected. The Shannon-Wiener Diversity Index, the Hilsenhoff family-level biotic index, family richness, and percent dipterans were calculated. Hilsenhoff family-level biotic index and percent dipterans metrics differed significantly among sampling sites (P < 0.05). Hilsenhoff family-level biotic index was higher at the most downstream site but percent dipterans were higher at site of discharge of effluent to the head of Blue Nile River. Therefore, there is indication that effluent demands frequent control and proper treatment before being discharged to the environment. PMID:26688685

  7. Nile River

    Atmospheric Science Data Center

    2013-04-15

    ... extent of the Nile waters before and after the onset of the rainy seasons of 2000 (top pair) and 2001 (bottom pair). The images are ... poor prior to the flooding due to a late start of the rainy season in parts of the country. Following two consecutive years of serious ...

  8. Evaluation of river discharges from ensemble global water resources reanalysis in the Upper Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Belay, Haileyesus; Moges, Semu; Nikolopoulos, Efthymios; Anagnostou, Emmanouil

    2017-04-01

    The increased capacity of observational datasets, both from in-situ and remote sensors, along with the continuous advancements in earth system models and data assimilation algorithms, have led to the generation of a number of water resources reanalysis products that are available at global scale and high spatial and temporal resolution. These products hold a great potential for studies and applications related to water resources but their level of accuracy and range of uncertainty needs to be investigated and understood. In this work, we analyze and evaluate the runoff estimates from a multi-model global water resources reanalysis (WRR) dataset that was recently produced within the framework of Earth2Observe project (http: //www.earth2observe.eu). Evaluation of the WRR reanalysis is based on the comparison of streamflows derived from the ensemble WRR and available in situ observations for a range of basin scales in the Upper Blue Nile basin in Ethiopia. Analysis is carried out for different runoff properties (e.g. volume, maximum flows, duration curves) and for different temporal scales (daily, seasonal, annual) in order to evaluate the ability of WRR-based runoff estimates to represent various runoff characteristics. Results clearly indicate that the basin area and temporal scale are the most important controls on the performance of WRR streamflow simulations. Furthermore, results allow providing recommendations on application-specific use of WRR products and discussing potential bias correction techniques for improving river streamflow simulations.

  9. The Nile River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of the northern portion of the Nile River was captured by MISR's nadir camera on January 30, 2001 (Terra orbit 5956). The Nile is the longest river in the world, extending for about 6700 kilometers from its headwaters in the highlands of eastern Africa. At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to the east. Also visible in this image is the Suez Canal, a shipping waterway connecting Port Said on the Mediterranean Sea with the Gulf of Suez. The Gulf is an arm of the Red Sea, and is located on the righthand side of the picture. Image credit: NASA/GSFC/LaRC/JPL, MISR Team.

  10. The Nile River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of the northern portion of the Nile River was captured by MISR's nadir camera on January 30, 2001 (Terra orbit 5956). The Nile is the longest river in the world, extending for about 6700 kilometers from its headwaters in the highlands of eastern Africa. At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to the east. Also visible in this image is the Suez Canal, a shipping waterway connecting Port Said on the Mediterranean Sea with the Gulf of Suez. The Gulf is an arm of the Red Sea, and is located on the righthand side of the picture. Image credit: NASA/GSFC/LaRC/JPL, MISR Team.

  11. Nile River Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The Nile River Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population. The capital city of Cairo is at the apex of the delta. Just across the river from Cairo can be seen the ancient three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  12. Nile River Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The Nile River Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population. The capital city of Cairo is at the apex of the delta. Just across the river from Cairo can be seen the ancient three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  13. Nile River Delta, Egypt

    NASA Image and Video Library

    1984-10-13

    The Nile River Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population. The capital city of Cairo is at the apex of the delta. Just across the river from Cairo can be seen the ancient three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  14. Comprehensive assessment of soil erosion risk for better land use planning in river basins: Case study of the Upper Blue Nile River.

    PubMed

    Haregeweyn, Nigussie; Tsunekawa, Atsushi; Poesen, Jean; Tsubo, Mitsuru; Meshesha, Derege Tsegaye; Fenta, Ayele Almaw; Nyssen, Jan; Adgo, Enyew

    2017-01-01

    In the drought-prone Upper Blue Nile River (UBNR) basin of Ethiopia, soil erosion by water results in significant consequences that also affect downstream countries. However, there have been limited comprehensive studies of this and other basins with diverse agroecologies. We analyzed the variability of gross soil loss and sediment yield rates under present and expected future conditions using a newly devised methodological framework. The results showed that the basin generates an average soil loss rate of 27.5tha(-1)yr(-1) and a gross soil loss of ca. 473Mtyr(-1), of which, at least 10% comes from gully erosion and 26.7% leaves Ethiopia. In a factor analysis, variation in agroecology (average factor score=1.32) and slope (1.28) were the two factors most responsible for this high spatial variability. About 39% of the basin area is experiencing severe to very severe (>30tha(-1)yr(-1)) soil erosion risk, which is strongly linked to population density. Severe or very severe soil erosion affects the largest proportion of land in three subbasins of the UBNR basin: Blue Nile 4 (53.9%), Blue Nile 3 (45.1%), and Jema Shet (42.5%). If appropriate soil and water conservation practices targeted ca. 77.3% of the area with moderate to severe erosion (>15tha(-1)yr(-1)), the total soil loss from the basin could be reduced by ca. 52%. Our methodological framework identified the potential risk for soil erosion in large-scale zones, and with a more sophisticated model and input data of higher spatial and temporal resolution, results could be specified locally within these risk zones. Accurate assessment of soil erosion in the UBNR basin would support sustainable use of the basin's land resources and possibly open up prospects for cooperation in the Eastern Nile region. Copyright © 2016 Office national des forêts. Published by Elsevier B.V. All rights reserved.

  15. Discover the Nile River

    ERIC Educational Resources Information Center

    Project WET Foundation, 2009

    2009-01-01

    Bordering on the Fantastic. As the longest river on earth, the Nile passes through 10 countries. Presented through a wide range of activities and a winning array of games, it's also unsurpassed at taking young minds into exploring the world of water, as well as natural and man made wonders.

  16. Discover the Nile River

    ERIC Educational Resources Information Center

    Project WET Foundation, 2009

    2009-01-01

    Bordering on the Fantastic. As the longest river on earth, the Nile passes through 10 countries. Presented through a wide range of activities and a winning array of games, it's also unsurpassed at taking young minds into exploring the world of water, as well as natural and man made wonders.

  17. Hydrological Response to Climate Change for Gilgel Abay River, in the Lake Tana Basin - Upper Blue Nile Basin of Ethiopia

    PubMed Central

    Dile, Yihun Taddele; Berndtsson, Ronny; Setegn, Shimelis G.

    2013-01-01

    Climate change is likely to have severe effects on water availability in Ethiopia. The aim of the present study was to assess the impact of climate change on the Gilgel Abay River, Upper Blue Nile Basin. The Statistical Downscaling Tool (SDSM) was used to downscale the HadCM3 (Hadley centre Climate Model 3) Global Circulation Model (GCM) scenario data into finer scale resolution. The Soil and Water Assessment Tool (SWAT) was set up, calibrated, and validated. SDSM downscaled climate outputs were used as an input to the SWAT model. The climate projection analysis was done by dividing the period 2010-2100 into three time windows with each 30 years of data. The period 1990-2001 was taken as the baseline period against which comparison was made. Results showed that annual mean precipitation may decrease in the first 30-year period but increase in the following two 30-year periods. The decrease in mean monthly precipitation may be as much as about -30% during 2010-2040 but the increase may be more than +30% in 2070-2100. The impact of climate change may cause a decrease in mean monthly flow volume between -40% to -50% during 2010-2040 but may increase by more than the double during 2070-2100. Climate change appears to have negligible effect on low flow conditions of the river. Seasonal mean flow volume, however, may increase by more than the double and +30% to +40% for the Belg (small rainy season) and Kiremit (main rainy season) periods, respectively. Overall, it appears that climate change will result in an annual increase in flow volume for the Gilgel Abay River. The increase in flow is likely to have considerable importance for local small scale irrigation activities. Moreover, it will help harnessing a significant amount of water for ongoing dam projects in the Gilgel Abay River Basin. PMID:24250755

  18. Hydrological response to climate change for Gilgel Abay River, in the Lake Tana Basin -Upper Blue Nile Basin of Ethiopia.

    PubMed

    Dile, Yihun Taddele; Berndtsson, Ronny; Setegn, Shimelis G

    2013-01-01

    Climate change is likely to have severe effects on water availability in Ethiopia. The aim of the present study was to assess the impact of climate change on the Gilgel Abay River, Upper Blue Nile Basin. The Statistical Downscaling Tool (SDSM) was used to downscale the HadCM3 (Hadley centre Climate Model 3) Global Circulation Model (GCM) scenario data into finer scale resolution. The Soil and Water Assessment Tool (SWAT) was set up, calibrated, and validated. SDSM downscaled climate outputs were used as an input to the SWAT model. The climate projection analysis was done by dividing the period 2010-2100 into three time windows with each 30 years of data. The period 1990-2001 was taken as the baseline period against which comparison was made. Results showed that annual mean precipitation may decrease in the first 30-year period but increase in the following two 30-year periods. The decrease in mean monthly precipitation may be as much as about -30% during 2010-2040 but the increase may be more than +30% in 2070-2100. The impact of climate change may cause a decrease in mean monthly flow volume between -40% to -50% during 2010-2040 but may increase by more than the double during 2070-2100. Climate change appears to have negligible effect on low flow conditions of the river. Seasonal mean flow volume, however, may increase by more than the double and +30% to +40% for the Belg (small rainy season) and Kiremit (main rainy season) periods, respectively. Overall, it appears that climate change will result in an annual increase in flow volume for the Gilgel Abay River. The increase in flow is likely to have considerable importance for local small scale irrigation activities. Moreover, it will help harnessing a significant amount of water for ongoing dam projects in the Gilgel Abay River Basin.

  19. Regional geomorphic analysis and gis susceptibility mapping of landslides in the blue nile and the tekeze river basins of ethiopia

    NASA Astrophysics Data System (ADS)

    Ismail, Elamin Hassan Dai

    The Plateau region of Ethiopia lies within a seismically active continental extensional regime, which is being rapidly incised by the Blue Nile and the Tekeze Rivers. Extremely large landslides pose serious hazards in this highly populated region (>27 million), which is in the process of developing its hydrologic resources. This research sought to develop cost-effective methods to compile regional landslide inventory and landslide susceptibility maps, using geomorphic tools and GIS technologies. This work also sought to evaluate the relationships between landslide dams and knickpoints, caused by channel bed incision from those caused by slope failures, by utilizing identified knickpoints along 56 tributary channels across the study area. The study employed the weighted overlay technique to produce regional landslide susceptibility hazard maps, and for the first time, employing wind-driven and integrated rainfall/aspect rasters at various inclination to more realistically model the actual precipitation that is felt by hillsides of varying azimuth, shape, and height. Landslides greater than 500m long were tentatively identified on 1:200,000 topographic maps draped over 30m hill-shade generated ASTER GDEMv2. The mapping revealed different types of landslides, and also revealed a considerable number of old, dormant landslide features. The use of wind-driven rainfall with integrated rainfall and aspect rasters provided a much more detailed and asymmetric distribution of precipitation. Spatial distribution of the very high and high hazard areas, during the Kermit and Belg rainy seasons by a range of 0.38% for an inclination of 40o and 1.7% for inclinations on 60o, as compared to the traditional assumption of 90o vertical rainfall, without integration of a slope aspect raster.

  20. Hydrogeological and hydrochemical framework of Upper Awash River basin, Ethiopia: With special emphasis on inter-basins groundwater transfer between Blue Nile and Awash Rivers

    NASA Astrophysics Data System (ADS)

    Yitbarek, Andarge; Razack, Moumtaz; Ayenew, Tenalem; Zemedagegnehu, Engida; Azagegn, Tilahun

    2012-04-01

    Integrated approach has been used to investigate the hydrogeological framework of a complex fractured volcanic aquifer system in the Upper Awash River basin located at the western shoulder of the Ethiopian Rift. The groundwater flow system and mechanism of recharge of different aquifers have been studied using conventional hydrogeological field investigations, hydrochemistry, and isotope hydrology. Litho-hydrostratigraphic relationships were constructed from lithologic logs obtained from exploratory drilling of deep boreholes. The result indicates quite complex flow pattern and hydraulic characteristics of the different volcanic aquifers. The litho-hydrostratigraphic correlation indicates that the permeable and porous scoraceous lower basaltic aquifer is extended laterally all the way from the Blue Nile Plateau to the study area. New evidences have also emerged on the inter-basin groundwater transfer. Two distinct regional basaltic aquifers (upper and lower) are identified showing distinct hydrochemical and isotopic signatures. In the southern part of the study area the upper and lower aquifers form one unconfined regional aquifer system. In the northern and central part of the basin, it appears that the two systems are separated by regional aquiclude forming confined aquifers, in places with artesian wells. The groundwater from the deep exploratory wells (>250 m) tapping the lower basaltic aquifer and wells located in the south were found to be moderately mineralized (TDS: 400-600 mg/l), with relatively depleted stable isotope composition and with almost zero tritium. In contrast, the upper shallow aquifer has lesser ionic concentration, more isotopically enriched. Evidences from the different methods clearly indicate inter-basin groundwater transfer from the Blue Nile basin to the Upper Awash basin. The evidences also converge to testify common origin of recharge, presence of hydraulic connectivity for systems tapping the lower basaltic aquifer. This has enormous

  1. Nile River Fluctuations Near Khartoum, Sudan

    NASA Image and Video Library

    2001-08-29

    Throughout history, the rising and falling waters of the mighty Nile River have directly impacted the lives of the people who live along its banks. These images of the area around Sudan's capital city of Khartoum capture the river's dynamic nature. Acquired by the Multi-angle Imaging SpectroRadiometer's nadir (vertical-viewing) camera, they display the extent of the Nile waters before and after the onset of the rainy seasons of 2000 (top pair) and 2001 (bottom pair). The images are displayed in "false color," using the camera's near-infrared, green, and blue bands. With this particular spectral combination, water appears in shades of blue and turquoise, and highly vegetated areas show up as bright red. Originating in Uganda and Ethiopia, respectively, the waters of the White Nile (western branch) and Blue Nile (eastern branch) converge at Khartoum (about half-way between image center and the left-hand side), and continue to flow northward as the Great Nile. Although the most obvious feature in these images is the increased width of the White Nile between spring and summer, careful inspection shows that the Great Nile is at its widest in August 2001 (note in particular the area between the clouds near the top of this panel). Heavy rains in the Blue Nile catchment area of the Ethiopian highlands led to a rapid overflow of the river's floodwaters into the main stream of the Great Nile, leading to extensive flooding, the worst effects of which occurred north of Khartoum. According to the Food and Agriculture Organization of the United Nations, tens of thousands of people have fled their homes, and the number of people in need of urgent food assistance in Sudan, estimated at three million earlier in the year, was likely to increase with the onset of these floods. South of the confluence of the White Nile and the Blue Nile, the area of a cross-hatched appearance is the irrigated plain of El Gezira. The Gezira irrigation scheme uses water from the Makwar Dam (now called

  2. Nile River, Lake Nasser, Aswan Dam, Egypt

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Egypt's High Aswan Dam on the Nile River at the first cataracts, Nile River, (24.0N, 33.0E) was completed in 1971 to provide cheap hydroelectric power and to regulate the historically uneven flow of the Nile River. The contrast between the largely base rock desert east of the Nile versus the sand covered desert west of the river and the ancient irrigated floodplain downstream from the damsite is clearly shown.

  3. Nile River, Lake Nasser, Aswan Dam, Egypt

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Egypt's High Aswan Dam on the Nile River at the first cataracts, Nile River, (24.0N, 33.0E) was completed in 1971 to provide cheap hydroelectric power and to regulate the historically uneven flow of the Nile River. The contrast between the largely base rock desert east of the Nile versus the sand covered desert west of the river and the ancient irrigated floodplain downstream from the damsite is clearly shown.

  4. Nile River, Lake Nasser, Aswan Dam, Egypt

    NASA Image and Video Library

    1991-08-11

    Egypt's High Aswan Dam on the Nile River at the first cataracts, Nile River, (24.0N, 33.0E) was completed in 1971 to provide cheap hydroelectric power and to regulate the historically uneven flow of the Nile River. The contrast between the largely base rock desert east of the Nile versus the sand covered desert west of the river and the ancient irrigated floodplain downstream from the damsite is clearly shown.

  5. Determining the Palaeodrainage of the Nile River from a Provenance Study of the Nile Delta Cone Sediments

    NASA Astrophysics Data System (ADS)

    Fielding, L.; Najman, Y.; Millar, I.; Butterworth, P.; Garzanti, E.; Kneller, B. C.

    2014-12-01

    This study documents the palaeodrainage history of the Nile River, in particular the time of its transition from a small locally sourced drainage network to the initiation of an extensive catchment. Today, the Nile drains as far south as Lake Victoria, with the White Nile draining largely cratonic rocks of Archean to Proterozoic age and the Blue Nile draining Cenozoic Ethiopian Continental Flood Basalts and Neoproterozoic basement. However, the timing of catchment expansion to the river's current extent is highly debated. Two end member models are: A) The Blue Nile did not connect with the lower Nile until the Late Messinian, and the White Nile not until 0.5 Ma. In this model, the pre-Messinian Nile delta sediments are locally derived from the Red Sea Hills (RSH) (Issawi and McCauley 1992). B) The Blue Nile has been connected to the lower Nile since the Oligocene (Burke and Wells 1989). Onshore fieldwork characterised each possible source area (Ethiopian flood basalts, Archean craton, and Neoproterozoic basement and Phanerozoic cover sequences of the RSH) using petrography, geochemistry and isotope studies. Tertiary-aged Nile delta sediments provide a unique archive of the river's palaeodrainage history, which were analysed from conventional core from exploration and appraisal wells in order to identify the occurrence (if any) of these sources in the delta geological record. Heavy mineral, petrographic, U/Pb rutile and Lu/Hf zircon analyses indicate Blue Nile and/or RSH input to the Nile delta since at least the Oligocene with very little input from the White Nile. Sr and Nd whole-rock analyses of mud samples allow discrimination between the Blue Nile and RSH sources and may, subject to further analyses, confirm Blue Nile input to the delta since the Oligocene. U-Pb zircon analyses reveal the presence of 20-30 Ma zircons in both the modern river sediments from the Ethiopian Highlands and the Nile Delta core from the early Miocene to present day indicating a

  6. Determining the palaeodrainage of the Nile river from a provenance study of the Nile delta cone sediments

    NASA Astrophysics Data System (ADS)

    Fielding, Laura; Najman, Yani; Millar, Ian; Butterworth, Peter; Garzanti, Eduardo; Kneller, Ben

    2014-05-01

    This study documents the palaeodrainage history of the Nile River, in particular the time of its transition from a small locally sourced drainage network to the initiation of an extensive catchment. Today, the Nile drains as far south as Lake Victoria, with the White Nile draining largely cratonic rocks of Archean to Proterozoic age and the Blue Nile draining Cenozoic Ethiopian Continental Flood Basalts and Neoproterozoic basement. However, the timing of catchment expansion to the river's current extent is highly debated. Two end member models are: A) The Blue Nile did not connect with the lower Nile until the Late Messinian, and the White Nile not until 0.5 Ma. In this model, the pre-Messinian Nile delta sediments are locally derived from the Red Sea Hills (RSH) (Issawi and McCauley 1992). B) The Blue Nile has been connected to the lower Nile since the Oligocene (Burke and Wells 1989). Onshore fieldwork characterised each possible source area (Ethiopian flood basalts, Archean craton, and Neoproterozoic basement and Phanerozoic cover sequences of the RSH) using petrography, geochemistry and isotope studies. Tertiary-aged Nile delta sediments provide a unique archive of the river's palaeodrainage history, which were analysed from conventional core from exploration and appraisal wells in order to identify the occurrence (if any) of these sources in the delta geological record. Heavy mineral, petrographic, U/Pb rutile and Lu/Hf zircon analyses indicate Blue Nile and/or RSH input to the Nile delta since at least the Oligocene with very little input from the White Nile. Sr and Nd whole-rock analyses of mud samples allow discrimination between the Blue Nile and RSH sources and may, subject to further analyses, confirm Blue Nile input to the delta since the Oligocene. U-Pb zircon analyses reveal the presence of 20-30 Ma zircons in both the modern river sediments from the Ethiopian Highlands and the Nile Delta core from the early Miocene to present day indicating a

  7. Visualising DNA in Classrooms Using Nile Blue

    ERIC Educational Resources Information Center

    Milne, Christine; Roche, Scott; McKay, David

    2008-01-01

    Giving students the opportunity to extract, manipulate and visualise DNA molecules enhances a constructivist approach to learning about modern techniques in biology and biotechnology Visualisation usually requires agarose gel electrophoresis and staining. In this article, we report on an alternative DNA stain, Nile Blue A, that may be used in the…

  8. Visualising DNA in Classrooms Using Nile Blue

    ERIC Educational Resources Information Center

    Milne, Christine; Roche, Scott; McKay, David

    2008-01-01

    Giving students the opportunity to extract, manipulate and visualise DNA molecules enhances a constructivist approach to learning about modern techniques in biology and biotechnology Visualisation usually requires agarose gel electrophoresis and staining. In this article, we report on an alternative DNA stain, Nile Blue A, that may be used in the…

  9. Nile Blue derivatives as lysosomotropic photosensitizers

    NASA Astrophysics Data System (ADS)

    Lin, Chi-Wei; Shulok, Janine R.; Kirley, S. D.; Cincotta, Louis; Foley, James W.

    1991-06-01

    The benzophenoxazines, including several Nile blue analogues, are a unique group of dyes that localize selectively in animal tumors. Chemical modifications of Nile blue A can yield derivatives with high 1O2 quantum yields. These derivatives represent a group of potentially effective photosensitizers for selective phototherapy of malignant tumors. In vitro evaluation of these derivatives has indicated that those with high 1O2 yields are very effective in mediating the photocytotoxicity of tumor cells. This photodynamic effect is most likely mediated through the action of 1O2, since photoirradiation under D2O enhanced and under hypoxic conditions diminished the photocytotoxic action. The subcellular localization of these photosensitizers in bladder tumor cells in culture was examined by light and fluorescence microscopies as well as by histochemical and biochemical studies. The results indicate that these dyes are localized primarily in the lysosome. The cellular uptake and retention of these dyes is energy- and pH-dependent. Agents such as nigericin, which alter the transmembrane pH gradient, reduced uptake and enhanced efflux of the dyes, while agents such as valinomycin, which reduce cellular membrane potential, had no effect on the uptake. These findings are consistent with having ion-trapping as the mechanism for the uptake of these dyes. Photoirradiation of sensitizer-treated cells obliterated lysosomes in a light-dose and drug-dose dependent fashion. Release of the hydrolytic enzymes may be the main cause for subsequent cell death since the cytolytic effect was reduced by a specific inhibitor of lysosomal proteolytic enzyme. A lysosomotropic photosensitization mechanism is therefore proposed for the photocytotoxic action of the Nile blue derivatives. This mechanism may provide an approach to the development of new photosensitizers for the effective and selective destruction of malignant tumors.

  10. Temporal variability of hydroclimatic extremes in the Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Taye, Meron Teferi; Willems, Patrick

    2012-03-01

    This paper examines the long-term historical changes in frequency and amplitude of hydroclimatic extremes in the Blue Nile basin using data from the second half of 20th century. The temporal variability of basin-wide rainfall extremes and river flow extremes from four gauging stations was investigated under the hypothesis of no trend and no persistence in time. On the basis of a quantile anomaly analysis method, decadal variations in extreme daily, monthly, and annual quantiles were studied, and the periods of statistical significance were identified. The analysis showed that high and low river flows and rainfall depths do not vary in time in a fully random way but show a particular variation pattern. Their extremes show significant decadal variations. The 1980s had statistically significant negative anomalies in extremes in comparison with the long-term reference period of 1964-2009, while the 1960s-1970s and the 1990s-2000s had positive anomalies, although less significant. There is neither consistent increasing nor decreasing trend in rainfall and flow extremes of recent years. Therefore, anticipated trends due to global warming could not be identified. Conversely, low-flow extremes show an increasing trend during the last decade, which could be related to the effect of water regulation works at the outlet of Lake Tana. Moreover, similar patterns and statistically significant correlations were found between climatic indices representing the Pacific and Atlantic Oceans and the Blue Nile rainfall and flow extremes. Changes that occur on the Pacific Ocean appear to be a main driver for the decadal oscillations in climate and related high and low Blue Nile water availability for Ethiopia, Sudan, and Egypt.

  11. A detrital record of the Nile River and its catchment

    NASA Astrophysics Data System (ADS)

    Fielding, Laura; Najman, Yani; Millar, Ian; Butterworth, Peter; Ando, Sergio; Padoan, Marta; Barfod, Dan; Kneller, Ben

    2017-04-01

    This research uses analyses from Nile catchment rivers, wadis, dunes and bedrocks to constrain the geological history of NE Africa and document influences on the composition of sediment reaching the Nile delta. Methods used include single grain analyses (U-Pb and Hf analyses of zircon, U-Pb dating of rutile, Ar-Ar dating of white mica and plagioclase), and bulk analyses (petrography, Sr, Nd and Hf isotopic analyses, and trace element concentrations). Our data show evolution of the North African crust, highlighting phases in the development of the Arabian-Nubian Shield and amalgamation of Gondwana in Neoproterozoic times. The Saharan Metacraton and Congo Craton in Uganda have a common history of crustal growth, with new crust formation at 3.0 - 3.5 Ga, and crustal melting at c. 2.7 Ga. The Hammamat Formation of the Arabian-Nubian Shield is locally derived and has a maximum depositional age of 635 Ma. By contrast, Phanerozoic sedimentary rocks are derived from more distant sources. In the modern Nile drainage, there is considerable evolution downstream, controlled predominantly by changes in local geology and geomorphology. The provenance signature of the White Nile is dramatically different upstream and downstream of the Sudd marshes as a result of sediment trapping. South of the Sudd, White Nile sediments are craton-derived. North of the Sudd, at Kosti, the signature of the White Nile is dominated by material derived from Phanerozoic sandstones supplied via alluvial fans to the west of the river. Further north, south of Khartoum, White Nile sediment composition is affected by its proximity to the Pleistocene Blue Nile sourced Gezira Fan. The Blue Nile's and Atbara's signatures are influenced predominantly by input from the Ethiopian flood basalts in terms of their bulk-rock signature, and by proximity to the Arabian-Nubian Shield in terms of zircon characteristics. A further shift in sediment signature in terms of zircon characteristics is seen by the time the Nile

  12. 20,000 years of Nile River dynamics and environmental changes in the Nile catchment area as inferred from Nile upper continental slope sediments

    NASA Astrophysics Data System (ADS)

    Revel, Marie; Ducassou, E.; Skonieczny, C.; Colin, C.; Bastian, L.; Bosch, D.; Migeon, S.; Mascle, J.

    2015-12-01

    Multi-proxy analysis of two marine sediment cores (MS27PT and MD04-2726) from the Nile continental slope provides evidence of changes in Nile sediment discharge related to changes in Ethiopian African Monsoon (EAM) precipitation, and allows us to reconstruct changes in Nile River runoff, vegetation and erosion in the Nile headwaters. Sediment element composition and neodymium isotopic composition reveal significant changes in clastic sediment provenance, with sources oscillating between a Saharan aeolian contribution during the Last Glacial Maximum/deglacial transition and during the Late Holocene, and a Blue/Atbara Nile fluvial contribution during the African Humid Period (AHP). This study provides a new understanding of past environmental changes. Between 14.6 and 14.13 ka there was a major input of sediments from the Ethiopian Highlands, consistent with a stronger EAM at that time. Climate in the Nile basin was wetter between 14.8 and 8.4 ka, with a corresponding increase in Blue Nile water and sediment discharge via the main Nile into the Eastern Mediterranean. The gradual climatic transition from the AHP to the present-day dry climate was reflected in a decrease in Blue Nile sediment deposition and flood discharge between 8.4 and 3.7 ka, with aridity at a maximum between 3.7 and 2.6 ka. The onset of drier conditions in the Blue Nile basin seems to have begun before the 8.2 ka cooling event in the North Atlantic. We speculate that the climatic change from the wet AHP to the dry late Holocene may have been a result of a break in the low latitude dynamic equilibrium between climate, vegetation and erosion, which may in turn have affected the climate in higher latitudes. Reduced Nile flow may also have had an impact on Levantine Intermediate Water originating in the Eastern Mediterranean through an increase in intermediate water formation.

  13. Ultrasound promoted synthesis of Nile Blue derivatives.

    PubMed

    Raju, B Rama; Sampaio, Diogo M F; Silva, M M; Coutinho, Paulo J G; Gonçalves, M Sameiro T

    2014-01-01

    Ultrasound irradiation was used for the first time towards the synthesis of new Nile Blue related benzo[a]phenoxazinium chlorides possessing isopentylamino, (2-cyclohexylethyl)amino and phenethylamino groups at 5-position of the heterocyclic system. The efficacy of sonochemistry was investigated with some of our earlier reported synthesis of benzo[a]phenoxazinium chlorides. This newer protocol proved competent in terms of reaction times and enhanced yields. Photophysical studies carried out in ethanol, water and simulated physiological conditions, revealed that emission maxima occurred in the range 644-656 nm, with high fluorescent quantum yields. Other attractive feature exhibited by these materials includes good thermal stability. These properties might be useful in the development of fluorescent probes for biotechnology. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Runoff and precipitation dynamics in the Blue and White Nile catchments during the mid-Holocene: A data-model comparison

    NASA Astrophysics Data System (ADS)

    Blanchet, C. L.; Contoux, C.; Leduc, G.

    2015-12-01

    The Blue Nile is the major contributor of freshwater and sediments to the modern-day main Nile River and exerts a key control on seasonal flooding in the Nile valley. Recent studies have postulated that the relative contribution from the Blue Nile to the main Nile runoff might have been reduced during the mid-Holocene, at a time when higher boreal summer insolation stimulated enhanced precipitation in North Africa. Whether the decrease in the relative contribution from the Blue Nile resulted from a decrease in precipitation over the catchment, from an increase in White Nile runoff or from a combination of both is still a matter of debate. By comparing regional proxy-records with the output from a global atmospheric model zoomed on Africa, we propose that the reduced contribution from the Blue Nile at 6 ka originated from both a higher White Nile runoff and a lower Blue Nile runoff. Enhanced African and Indian monsoons at 6 ka induced a northern shift of the Intertropical Convergence Zone and an eastward shift of the Congo Air Boundary. Such an atmospheric configuration led to a negative anomaly of summer precipitation over the Blue Nile catchment that likely resulted in a reduction in the Blue Nile runoff. By contrast, a sustained positive anomaly of precipitation over the White Nile catchment during both summer and autumn most likely induced a higher main Nile runoff during the mid-Holocene. Using the model output, we propose a first synoptic view on regional rainfall dynamics that permits to reconcile contrasting proxy records.

  15. Space Radar Image of Nile River Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows the area just north of the city of Cairo, Egypt, where the Nile River splits into two main branches. The Rosetta Branch is the curving dark line in the center of the image and the Damietta Branch is the curving dark line in the lower right of the image. The light blue area on the right half of the image is a portion of the Nile River Delta. The thinner, straighter lines and the small network of gold lines are irrigation canals. There are more than 10,000 kilometers of canals throughout the Nile Delta. A transition zone of irrigated fields is shown in blue and yellow between the irrigated delta and the surrounding desert. The desert is the dark blue area on the left side of the image lacking the pattern of irrigated fields. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) on October 4, 1994, onboardthe space shuttle Endeavour. The image is 75 kilometers by 60 kilometers (46 miles by 37 miles) and is centered at 30.2 degreesnorth latitude, 31.1 degrees east longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted and received; and blue is the ratio of C-band and L-band, horizontally transmitted and received. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to PlanetEarth program.

  16. Aswan Dam, Lake Nassar, Nile River, Egypt

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Aswan Dam on the Nile River created the 500 kilometer long reservoir, seen here in sunglint. Lake Nassar (23.5N, 33.0E) was designed to control the devestating floods and alleviate the famine-producing droughts which have plagued the region for millenia. In Nov 81, as the lake was nearing capacity, drought conditions lowered the water level by about 30 meters which can clearly be seen as silt depositions on the receding eastern shoreline.

  17. Effects of the Indian Ocean Temperature on Nile River Flow Volumes

    NASA Astrophysics Data System (ADS)

    Becker, R.; Sultan, M.; Becker, D.

    2009-12-01

    Egypt and Sudan are heavily dependent on the Nile River for sustaining their populations. In high flow years, the Lake Nasser surface water levels rise and overflows filling surrounding natural depressions and forming additional lakes (Tushka lakes) in peak flow years. The underlying Nubian Aquifer is recharged in high flow yeas, whereas the Nubian groundwater discharges into the Nile in low flow years. Previous studies have shown that the variability in flow volumes in the Nile River can be partially (~30%) accounted for by variations in the intensity of El Niño Southern Oscillation (ENSO) events. Other previous studies suggested that rainfall in the upper Blue Nile catchment in Sudan can be linked to changes in the intensity of temperature variations across the Indian Ocean (the Indian Ocean Dipole or IOD). To test which of these events correlate best with Nile flow volumes, Nile flow records in the Blue Nile (above Khartoum), the White Nile (above Kharthoum), and combined flow at Wadi Halfa covering the time period from 1902 to 1962 were analyzed together with SST measurements. Peak and minimum discharge, and quarterly measurement from each gauge were obtained. The intensity of El Nino 3.4 and 4, and of the Indian Ocean Dipole variations from the reconstructed SST dataset hadlSST covering the same time period were used. The best correlation was found to exist between fluctuations in the IOD in the Spring (Apr-May-Jun) preceding the peak flow (usually occurring in August) and maximum discharge at the Blue Nile Gauge above Khartoum (Correlation coefficient of 0.65). Variations in El Nino intensity for the same time period showed lower correlations with peak and base Nile flow in the Blue Nile (0.55). This indicates that the intensity of the Indian Ocean Dipole has been a better predictor than El Nino for peak Nile Flow volume. Results highlight the potential for using the latter relationship for predicting Nile Flow volumes flowing in Lake Nasser and for modeling

  18. From non-covalent binding to irreversible DNA lesions: nile blue and nile red as photosensitizing agents

    NASA Astrophysics Data System (ADS)

    Gattuso, Hugo; Besancenot, Vanessa; Grandemange, Stéphanie; Marazzi, Marco; Monari, Antonio

    2016-06-01

    We report a molecular modeling study, coupled with spectroscopy experiments, on the behavior of two well known organic dyes, nile blue and nile red, when interacting with B-DNA. In particular, we evidence the presence of two competitive binding modes, for both drugs. However their subsequent photophysical behavior is different and only nile blue is able to induce DNA photosensitization via an electron transfer mechanism. Most notably, even in the case of nile blue, its sensitization capabilities strongly depend on the environment resulting in a single active binding mode: the minor groove. Fluorescence spectroscopy confirms the presence of competitive interaction modes for both sensitizers, while the sensitization via electron transfer, is possible only in the case of nile blue.

  19. From non-covalent binding to irreversible DNA lesions: nile blue and nile red as photosensitizing agents

    PubMed Central

    Gattuso, Hugo; Besancenot, Vanessa; Grandemange, Stéphanie; Marazzi, Marco; Monari, Antonio

    2016-01-01

    We report a molecular modeling study, coupled with spectroscopy experiments, on the behavior of two well known organic dyes, nile blue and nile red, when interacting with B-DNA. In particular, we evidence the presence of two competitive binding modes, for both drugs. However their subsequent photophysical behavior is different and only nile blue is able to induce DNA photosensitization via an electron transfer mechanism. Most notably, even in the case of nile blue, its sensitization capabilities strongly depend on the environment resulting in a single active binding mode: the minor groove. Fluorescence spectroscopy confirms the presence of competitive interaction modes for both sensitizers, while the sensitization via electron transfer, is possible only in the case of nile blue. PMID:27329409

  20. Coordinating and Negotiating Blue Nile Water Resource Development

    NASA Astrophysics Data System (ADS)

    Geressu, R. T.; Harou, J. J.

    2016-12-01

    Many countries are proposing new reservoirs in transboundary river basins world-wide that impact downstream regions. Failure to consider and incorporate multiple stakeholder interests in system design and decision making could contribute to regional disputes. Negotiated introduction of new assets and associated coordination strategies (e.g. cost and power sharing arrangements) could reduce conflict and help achieve consensus. In multi-stakeholders problems, parties are likely to prioritize performance targets differently and hence will often prefer different water system designs, stalling negotiations. An ideal solution is where individual and group benefits are maximized by allocating (exchanging) resources according to the relative preferences of stakeholders. Hence, a negotiation support mechanism should be able to incorporate stakeholder preference information. In this paper, we propose a three-step search & deliberate, elicit preferences, and search & negotiate approach for supporting negotiations in complex infrastructure-environmental systems. The approach seeks to find designs and coordination mechanisms that are more beneficial than non-cooperative actions. The proposed approach is applied to a stylized Blue Nile reservoir design problem in Ethiopia seeking to set reservoir capacity and operating rules. We consider cost and energy performance metrics for Ethiopia and energy and irrigation water supply in Sudan. We use example stakeholder (i.e., Ethiopian and Sudanese) priorities for demonstration purpose. The result is an agreed system design and coordination schemes (co-financing and power trade). The application results demonstrate that incorporating coordination strategies, such as energy trade, cost sharing, and financing in assessing transboundary reservoir development options could help find compromise designs that different parties can support.

  1. Natural equilibria and anthropic effects on sediment transport in big river systems: The Nile case

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Vezzoli, Giovanni; Villa, Igor

    2014-05-01

    The Nile River flows for ~ 6700 km, from Burundi and Rwanda highlands south of the Equator to the Mediterranean Sea at northern subtropical latitudes. It is thus the longest natural laboratory on Earth, a unique setting in which we are carrying out a continuing research project to investigate changes in sediment composition associated with a variety of chemical and physical processes, including weathering in equatorial climate and hydraulic sorting during transport and deposition. Petrographic, mineralogical, chemical, and isotopic fingerprints of sand and mud have been monitored along all Nile branches, from the Kagera and White Nile draining Archean, Paleoproterozoic and Mesoproterozoic basements uplifted along the western branch of the East African rift, to the Blue Nile and Atbara Rivers sourced in Ethiopian volcanic highlands made of Oligocene basalt. Downstream of the Atbara confluence, the Nile receives no significant tributary water and hardly any rainfall across the Sahara. After construction of the Aswan High Dam in 1964, the Nile ceased to be an active conveyor-belt in Egypt, where the mighty river has been tamed to a water canal; transported sediments are thus chiefly reworked from older bed and levee deposits, with minor contributions from widyan sourced in the Red Sea Hills and wind-blown desert sand and dust. Extensive dam construction has determined a dramatic sediment deficit at the mouth, where deltaic cusps are undergoing ravaging erosion. Nile delta sediments are thus recycled under the effect of dominant waves from the northwest, the longest Mediterranean fetch direction. Nile sands, progressively enriched in more stable minerals such as quartz and amphiboles relative to volcanic rock fragments and pyroxene, thus undergo multistep transport by E- and NE-directed longshore currents all along the coast of Egypt and Palestine, and are carried as far as Akko Bay in northern Israel. Nile mud reaches the Iskenderun Gulf in southern Turkey. A full

  2. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt

    PubMed Central

    Megahed, Ayman Mohamed; Dahshan, Hesham; Abd-El-Kader, Mahdy A.; Abd-Elall, Amr Mohamed Mohamed; Elbana, Mariam Hassan; Nabawy, Ehab; Mahmoud, Hend A.

    2015-01-01

    Ten polychlorinated biphenyl (PCB) congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD). PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt. PMID:26798844

  3. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt.

    PubMed

    Megahed, Ayman Mohamed; Dahshan, Hesham; Abd-El-Kader, Mahdy A; Abd-Elall, Amr Mohamed Mohamed; Elbana, Mariam Hassan; Nabawy, Ehab; Mahmoud, Hend A

    2015-01-01

    Ten polychlorinated biphenyl (PCB) congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD). PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt.

  4. Hydroclimate variability in the Nile River Basin during the past 28,000 years

    NASA Astrophysics Data System (ADS)

    Castañeda, Isla S.; Schouten, Stefan; Pätzold, Jürgen; Lucassen, Friedrich; Kasemann, Simone; Kuhlmann, Holger; Schefuß, Enno

    2016-03-01

    It has long been known that extreme changes in North African hydroclimate occurred during the late Pleistocene yet many discrepancies exist between sites regarding the timing, duration and abruptness of events such as Heinrich Stadial (HS) 1 and the African Humid Period (AHP). The hydroclimate history of the Nile River is of particular interest due to its lengthy human occupation history yet there are presently few continuous archives from the Nile River corridor, and pre-Holocene studies are rare. Here we present new organic and inorganic geochemical records of Nile Basin hydroclimate from an eastern Mediterranean (EM) Sea sediment core spanning the past 28 ka BP. Our multi-proxy records reflect the fluctuating inputs of Blue Nile versus White Nile material to the EM Sea in response to gradual changes in local insolation and also capture abrupt hydroclimate events driven by remote climate forcings, such as HS1. We find strong evidence for extreme aridity within the Nile Basin evolving in two distinct phases during HS1, from 17.5 to 16 ka BP and from 16 to 14.5 ka BP, whereas peak wet conditions during the AHP are observed from 9 to 7 ka BP. We find that zonal movements of the Congo Air Boundary (CAB), and associated shifts in the dominant moisture source (Atlantic versus Indian Ocean moisture) to the Nile Basin, likely contributed to abrupt hydroclimate variability in northern East Africa during HS1 and the AHP as well as to non-linear behavior of hydroclimate proxies. We note that different proxies show variable gradual and abrupt responses to individual hydroclimate events, and thus might have different inherent sensitivities, which may be a factor contributing to the controversy surrounding the abruptness of past events such as the AHP. During the Late Pleistocene the Nile Basin experienced extreme hydroclimate fluctuations, which presumably impacted Paleolithic cultures residing along the Nile corridor.

  5. Late Pleistocene desiccation of Lake Tana, source of the Blue Nile

    NASA Astrophysics Data System (ADS)

    Lamb, Henry F.; Bates, C. Richard; Coombes, Paul V.; Marshall, Michael H.; Umer, Mohammed; Davies, Sarah J.; Dejen, Eshete

    2007-02-01

    High-resolution seismic data from Lake Tana, the source of the Blue Nile in northern Ethiopia, reveal a deep sedimentary sequence divided by four strong reflectors. Data from nearshore cores show that the uppermost strong reflector represents a stiff silt unit, interpreted as a desiccation surface. Channel cuts in this surface, bordered by levee-like structures, are apparent in the seismic data from near the lake margin, suggesting fluvial downcutting and over-bank deposition during seasonal flood events. Periphytic diatoms and peat at the base of a core from the deepest part of the lake overlie compacted sediments, indicating that desiccation was followed by development of shallow-water environments and papyrus swamp in the central basin between 16,700 and 15,100 cal BP. As the lake level rose, open-water evaporation from the closed lake caused it to become slightly saline, as indicated by halophytic diatoms. An abrupt return to freshwater conditions occurred at 14,750 cal BP, when the lake overflowed into the Blue Nile. Further reflection surfaces with downcut structures are identifiable in seismic images of the overlying sediments, suggesting at least two lesser lake-level falls, tentatively dated to about 12,000 and 8000 cal BP. Since Lake Victoria, the source of the White Nile, was also dry until 15,000 cal BP, and did not reach overflow until 14,500 cal BP, the entire Nile system must have been reduced to intermittent seasonal flow until about 14,500 cal BP, when baseflow was re-established with almost simultaneous overflow of the headwater lakes of both the White and Blue Nile rivers. Desiccation of the Nile sources coincides with Heinrich event 1, when cessation of northward heat transport from the tropical Atlantic disrupted the Atlantic monsoon, causing drought in north tropical Africa. The strong reflectors at deeper levels in the seismic sequence of Lake Tana may represent earlier desiccation events, possibly contemporaneous with previous Late

  6. Cairo, Egypt/Nile River viewed from STS-66 Atlantis

    NASA Image and Video Library

    1994-11-14

    This close-up view of the intensively cultivated Nile River flood plain near Cairo presents a sharp color contrast to the virtually non-vegetated, sandy desert, located to the west of the vegetated area. Some rectangular cultivated field patterns, as well as circular center pivot irrigation patterns, can be observed northwest of the Nile River flood plain. The world famous Giza Pyramids are located near the center of this photography (see highly reflective sand surfaces).

  7. Shale gas characterization of the Dinder and Blue Nile Formations in the Blue Nile Basin, East Sudan

    NASA Astrophysics Data System (ADS)

    Shoieb, Monera Adam; Sum, Chow Weng; Bhattachary, Swapan Kumar; Abidin, Nor Syazwani Zainal; Abdelrahim, Omer Babiker

    2016-11-01

    The development of gas and oil in unconventional plays in United State and Northern Europe has affected the finances and the energy security. Geochanical properties of shale rocks can have a major impact on the efficiency of shale gas exploration. The goal of this study is to evaluate shale gas potentiality in the Blue Nile Basin, using samples from existing drilled wells. All the samples were analyzed in detail with the following organic geochemical techniques: total organic carbon (TOC), Rock-eval pyrolysis, to determine the quality and quantity of the organic matter. The total organic carbon (TOC) values for the shale intervals vary from 0.6 to 4.5weight% in FARASHA-1 Well, while in TAWAKUL-1 Well range from 0.4 to 2.4weight%, suggesting that fair to good source generative potential, as revealed by the S2 v's TOC plot. Hydrogen index (HI) values range from 12 to 182 mg HC/g TOC in the two wells, indicating type III and IV derived-input in the samples and their potential to generate gas. However, the Blue Nile and Dinder Formation have Tmax values in the range of 437 to 456°C, indicating early maturity in the oil window. Thus, higher maturity levels have affected the hydrocarbon generation potential and HI of the samples.

  8. Hydrological characterization of watersheds in the Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Gebrehiwot, S. G.; Ilstedt, U.; Gärdenas, A. I.; Bishop, K.

    2010-07-01

    We made a hydrological characterization of 32 watersheds (31-4350 km2) in the Blue Nile Basin, using data from a study of water and land resources in the Blue Nile Basin, Ethiopia published in 1964 by the US Bureau of Reclamation (USBR). The USBR document contains data on flow, climate, topography, geology, soil type, and land use for the period from 1959 to 1963. The aim of the study was to identify which combination of watershed variables best explain the variation in the hydrological regime, with special focus to low flow and, what kind of land use low flow might benefit from. Principal Component Analysis (PCA) and Partial Least Square (PLS) were used to analyze the relationship between hydrologic variables (total flow, maximum flow, minimum flow, runoff coefficient, and low flow index) and 30 potential watershed variables. We found that three groups of watershed variables - climate and topography, geology and soil, and land use had almost equal influence on the variation in the hydrologic variables (R2 values ranging from 0.3 to 0.5). The individual variables which were selected based on statistical significance from all groups of explanatory variables were better in explaining the variation. Low flow was positively correlated most strongly to wetland, wood land, rainfall, luvisols, and alluvial soils. Low flow was negatively correlated to grazing land, bush land, tuffs/basalts, eutric-vertisols and riverine forest. We concluded that low flow benefits from the land use types that preserve soil quality and water storage, such as wetland, savannah and woodland, while it was lower in land use resulting in soil degradation. Therefore it provides support to the theory that some land use such as grassland, can promote higher low flow

  9. Climate change enhances interannual variability of the Nile river flow

    NASA Astrophysics Data System (ADS)

    Siam, Mohamed S.; Eltahir, Elfatih A. B.

    2017-04-01

    The human population living in the Nile basin countries is projected to double by 2050, approaching one billion. The increase in water demand associated with this burgeoning population will put significant stress on the available water resources. Potential changes in the flow of the Nile River as a result of climate change may further strain this critical situation. Here, we present empirical evidence from observations and consistent projections from climate model simulations suggesting that the standard deviation describing interannual variability of total Nile flow could increase by 50% (+/-35%) (multi-model ensemble mean +/- 1 standard deviation) in the twenty-first century compared to the twentieth century. We attribute the relatively large change in interannual variability of the Nile flow to projected increases in future occurrences of El Niño and La Niña events and to observed teleconnection between the El Niño-Southern Oscillation and Nile River flow. Adequacy of current water storage capacity and plans for additional storage capacity in the basin will need to be re-evaluated given the projected enhancement of interannual variability in the future flow of the Nile river.

  10. Role of the Indian Ocean sea surface temperature in shaping the natural variability in the flow of Nile River

    NASA Astrophysics Data System (ADS)

    Siam, Mohamed S.; Wang, Guiling; Demory, Marie-Estelle; Eltahir, Elfatih A. B.

    2014-08-01

    A significant fraction of the inter-annual variability in the Nile River flow is shaped by El Niño Southern Oscillation (ENSO). Here, we investigate a similar role for the Indian Ocean (IO) sea surface temperature (SST) in shaping the inter-annual variability of the Nile River flow. Using observations of global SST distribution and river flow in addition to atmospheric general circulation model sensitivity experiments, we show that North and Middle IO SSTs play a significant intermediate role in the teleconnection between ENSO and the Nile flow. Applying partial coherency analyses, we demonstrate that the connection between North and Middle IO SSTs and Nile flow is strongly coupled to ENSO. During El Niño events, SST in the North and Middle IO increases in response to the warming in the Tropical Eastern Pacific Ocean and forces a Gill-type circulation with enhanced westerly low-level flow over East Africa and the Western IO. This anomalous low-level flow enhances the low-level flux of air and moisture away from the Upper Blue Nile (UBN) basin resulting in reduction of rainfall and river flow. SSTs in the South IO also play a significant role in shaping the variability of the Nile flow that is independent from ENSO. A warming over the South IO, generates a cyclonic flow in the boundary layer, which reduces the cross-equatorial meridional transport of air and moisture towards the UBN basin, favoring a reduction in rainfall and river flow. This independence between the roles of ENSO and South IO SSTs allows for development of new combined indices of SSTs to explain the inter-annual variability of the Nile flow. The proposed teleconnections have important implications regarding mechanisms that shape the regional impacts of climate change over the Nile basin.

  11. Scanning Electrochemical Microscopy of DNA Monolayers Modified with Nile Blue

    PubMed Central

    Gorodetsky, Alon A.; Hammond, William J.; Hill, Michael G.; Slowinski, Krzysztof; Barton, Jacqueline K.

    2009-01-01

    Scanning electrochemical microscopy (SECM) is used to probe long-range charge transport (CT) through DNA monolayers containing the redox-active Nile Blue (NB) intercalator covalently affixed at a specific location in the DNA film. At substrate potentials negative of the formal potential of covalently attached NB, the electrocatalytic reduction of Fe(CN)63− generated at the SECM tip is observed only when NB is located at the DNA/solution interface; for DNA films containing NB in close proximity to the DNA/electrode interface, the electrocatalytic effect is absent. This behavior is consistent with both rapid DNA-mediated CT between the NB intercalator and the gold electrode as well as a rate-limiting electron transfer between NB and the solution phase Fe(CN)63−. The DNA-mediated nature of the catalytic cycle is confirmed through sequence-specific and localized detection of attomoles of TATA-binding protein, a transcription factor that severely distorts DNA upon binding. Importantly, the strategy outlined here is general and allows for the local investigation of the surface characteristics of DNA monolayers both in the absence and in the presence of DNA binding proteins. These experiments highlight the utility of DNA-modified electrodes as versatile platforms for SECM detection schemes that take advantage of CT mediated by the DNA base pair stack. PMID:19053641

  12. Nile River, Lake Nasser, Aswan High Dam, Egypt, Africa

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Lake Nasser, (24.0N, 33.0E) at the Aswan High Dam on the Nile River, in Egypt is the world's second largest artificial lake, extending 500 km, in length and about 5000 sq. km. in area. The lake has a storage capacity sufficient to irrigate farms in Egypt and Sudan year round allowing up to three harvests per year. Other benefits include year round river navagation, hydroelectric power, more fish harvests, reduced flooding and more industrial employment. opportunites.

  13. Nile River, Lake Nasser, Aswan High Dam, Egypt, Africa

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Lake Nasser, (24.0N, 33.0E) at the Aswan High Dam on the Nile River, in Egypt is the world's second largest artificial lake, extending 500 km, in length and about 5000 sq. km. in area. The lake has a storage capacity sufficient to irrigate farms in Egypt and Sudan year round allowing up to three harvests per year. Other benefits include year round river navagation, hydroelectric power, more fish harvests, reduced flooding and more industrial employment. opportunites.

  14. Hydro-economic Risk Assessment in the Eastern Nile River Basin

    NASA Astrophysics Data System (ADS)

    Arjoon, D.; Tilmant, A.; Mohamed, Y.

    2013-12-01

    In 2011, the Ethiopian government announced plans for the construction of the Grand Renaissance Dam (GRD) on the Blue Nile, just east of its border with Sudan, at a cost of almost 5 billion dollars. The project is expected to generate over 15 TWh of energy and will include a reservoir of more than 60 km3 capacity, which roughly corresponds to the average annual flow of the Blue Nile. This project is part of a larger scheme, by the government, to expand its hydroelectric power capacity, however, the scheme faces strong opposition from downstream Egypt and Sudan. Egypt and Sudan are highly dependent on flows that originate in Ethiopia (it has been estimated that 86% of Nile flow originates in the Ethiopian highlands). The Ethiopian government argues that the dam would supply electricity for Ethiopians as well as generate surplus energy for export to neighboring countries. The Ethiopians also argue that the huge reservoir would generate positive externalities downstream by reducing floods and providing more constant and predictable lows. This study attempts to provide an independent analysis of the hydrologic and economic risks faced by downstream countries when GRD will be online. To achieve this, an integrated, stochastic hydro-economic model of the entire Eastern Nile basin is used to analyze various development and management scenarios. The results indicate that if countries agree to co- operative management of the Eastern Nile River basin, GRD would indeed significantly increase basin-wide benefits, especially in Ethiopia and in Sudan. An alternative management scenario, whereby GRD would be operated by Sudan and Egypt, does not yield significant economic gains in these countries. However, massive unilateral irrigation developments in Ethiopia will be detrimental for all countries, including Ethiopia itself, due to the huge opportunity costs involved.

  15. Hydrological responses to land use/cover changes in the source region of the Upper Blue Nile Basin, Ethiopia.

    PubMed

    Woldesenbet, Tekalegn Ayele; Elagib, Nadir Ahmed; Ribbe, Lars; Heinrich, Jürgen

    2017-01-01

    Understanding how changes in distinctive land use/land cover (LULC) types influence the basin hydrology would greatly improve the predictability of the hydrological consequences of LULC dynamics for sustainable water resource management. As the main flow contributor to the River Nile, quantifying the effect of LULC change on water resources in the source regions is very important for the assessment of water resources availability and management downstream in the riparian states in general and the study watersheds in particular. In this study, an integrated approach comprising hydrological modeling and partial least squares regression (PLSR) was used to quantify the contributions of changes in individual LULC classes to changes in hydrological components. Two watersheds, namely Lake Tana and Beles in the Upper Blue Nile Basin in Ethiopia, were considered for the conduction of hydrological modeling using LULC maps and the Soil and Water Assessment Tool (SWAT). In the Tana sub-basin, it is found that expansion of cultivation land and decline in woody shrub are the major contributors to the rise in surface run-off and to the decline in the groundwater component. Similarly, decline of woodland and expansion of cultivation land are the major contributors to the increase in surface run-off and water yield in the Beles sub-basin. Increased run-off and reduced baseflow and actual evapotranspiration would have negative impacts on water resources, especially in relation to erosion and sedimentation in the upper Blue Nile River Basin. As a result, expansion of cultivation land and decline in woody shrub/woodland appear to be major environmental stressors affecting local water resources. The wider implications of the hydrological changes on the Easter Nile water resources are briefly discussed. The approach to assessing changes in basin hydrology could generally be applied to a variety of other watersheds for which temporal digital LULC maps are available.

  16. Titan Nile-Like River Valley

    NASA Image and Video Library

    2012-12-12

    This image from NASA Cassini spacecraft shows a vast river system on Saturn moon Titan. It is the first time images from space have revealed a river system so vast and in such high resolution anywhere other than Earth.

  17. Nile tilapia and blue tilapia fry production in a subtropical climate

    USDA-ARS?s Scientific Manuscript database

    The relationship between production in earthen ponds located in a subtropical climate of fry suitable for hormonal sex inversion and degree-days was quantified for Nile tilapia (Oreochromis niloticus; Egypt strain) and blue tilapia (O. aureus). Degree-days were calculated for each trial as the sum o...

  18. Screening reservoir systems by considering the efficient trade-offs—informing infrastructure investment decisions on the Blue Nile

    NASA Astrophysics Data System (ADS)

    Geressu, Robel T.; Harou, Julien J.

    2015-12-01

    Multi-reservoir system planners should consider how new dams impact downstream reservoirs and the potential contribution of each component to coordinated management. We propose an optimized multi-criteria screening approach to identify best performing designs, i.e., the selection, size and operating rules of new reservoirs within multi-reservoir systems. Reservoir release operating rules and storage sizes are optimized concurrently for each separate infrastructure design under consideration. Outputs reveal system trade-offs using multi-dimensional scatter plots where each point represents an approximately Pareto-optimal design. The method is applied to proposed Blue Nile River reservoirs in Ethiopia, where trade-offs between total and firm energy output, aggregate storage and downstream irrigation and energy provision for the best performing designs are evaluated. This proof-of concept study shows that recommended Blue Nile system designs would depend on whether monthly firm energy or annual energy is prioritized. 39 TWh/yr of energy potential is available from the proposed Blue Nile reservoirs. The results show that depending on the amount of energy deemed sufficient, the current maximum capacities of the planned reservoirs could be larger than they need to be. The method can also be used to inform which of the proposed reservoir type and their storage sizes would allow for the highest downstream benefits to Sudan in different objectives of upstream operating objectives (i.e., operated to maximize either average annual energy or firm energy). The proposed approach identifies the most promising system designs, reveals how they imply different trade-offs between metrics of system performance, and helps system planners asses the sensitivity of overall performance to the design parameters of component reservoirs.

  19. Causal links between Nile floods and eastern Mediterranean sapropel formation during the past 125 kyr confirmed by OSL and radiocarbon dating of Blue and White Nile sediments

    NASA Astrophysics Data System (ADS)

    Williams, M. A. J.; Duller, G. A. T.; Williams, F. M.; Woodward, J. C.; Macklin, M. G.; El Tom, O. A. M.; Munro, R. N.; El Hajaz, Y.; Barrows, T. T.

    2015-12-01

    It has long been hypothesised that beds of highly organic mud or sapropels seen in marine sediment cores retrieved from the floor of the eastern Mediterranean accumulated during times of high Nile fluvial discharge. Our recent fieldwork in the valleys of the Blue Nile, the White Nile and the main Nile has for the first time revealed a sequence of extreme flood episodes synchronous with sapropel units S5 (124 kyr), S4 (102 kyr), S3 (81 kyr), S2 (55 kyr) and S1 (13.5-6.5 kyr). There are more weakly defined links with Nile floods and sapropel units S9 (240 kyr), S8 (217 kyr), S7 (195 kyr), S6 (172 kyr), but the dating error terms are too large to allow us to be too definite. During times of extreme floods over the past 125 kyr, wide distributary channels of the Blue Nile flowed across the Gezira alluvial fan in central Sudan and transported a bed load of sand and gravel into the lower White Nile valley. The sands were reworked by wind to form source-bordering dunes, all of which contain heavy minerals of Ethiopian provenance. These source-bordering dunes were active at 115-105 kyr, 60 kyr and 12-7 kyr, all times of extreme Blue Nile floods. The flood and dune sediments were dated using a combination of optically stimulated luminescence (OSL) and radiocarbon analyses. The Quaternary record of Nile floods discussed here shows a precessional signal and reflects episodes of stronger summer monsoon and more northerly seasonal movement of the ITCZ, linked to times of higher insolation in northern tropical latitudes. Progressive aggradation of Holocene Nile channels in northern Sudan has had a profound influence upon human settlement in the last 8 kyr.

  20. Sediment concentration rating curves for a monsoonal climate: upper Blue Nile

    NASA Astrophysics Data System (ADS)

    Moges, Mamaru A.; Zemale, Fasikaw A.; Alemu, Muluken L.; Ayele, Getaneh K.; Dagnew, Dessalegn C.; Tilahun, Seifu A.; Steenhuis, Tammo S.

    2016-07-01

    Information on sediment concentration in rivers is important for design of reservoirs and for environmental applications. Because of the scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile Basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decreases linearly with effective rainfall towards source-limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100 ha watersheds for which historic data were available. The results show that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.

  1. Sediment concentration rating curves for a monsoonal climate: upper Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Moges, M. A.; Zemale, F. A.; Alemu, M. L.; Ayele, G. K.; Dagnew, D. C.; Tilahun, S. A.; Steenhuis, T. S.

    2015-12-01

    Information on sediment content in rivers is important for design of reservoirs and for environmental applications. Because of scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decrease linearly with effective rainfall towards source limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100-ha watersheds for which historic data was available. The results show, that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.

  2. Earth view over Egypt and the Nile River taken during STS-121

    NASA Image and Video Library

    2006-07-04

    STS121-334-026 (4-17 July 2006) --- This photo, featuring an easterly view of the Nile River, the Nile River Delta, Sinai Peninsula, the Suez Canal, Red Sea and part of the Mediterranean Sea, was taken by one of the STS-121 crewmembers aboard the Space Shuttle Discovery. Cairo, Egypt, can be seen at far right.

  3. Sedimentation of the Triassic Jurassic Adigrat Sandstone Formation, Blue Nile (Abay) Basin, Ethiopia

    NASA Astrophysics Data System (ADS)

    Wolela, A.

    2008-09-01

    Exploration of oil and gas deposits in the Blue Nile Basin targeted the Adigrat Sandstone Formation as a reservoir objective. Conglomerates, gravely sandstones, coarse to medium-grained sandstones, very fine-grained cross-bedded sandstones, siltstones and mudstones of the Adigrat Sandstone Formation were deposited in semi-arid to arid climates. The North-western highlands are the main source for the sedimentation. The poorly-sorted, crudely-bedded conglomerates and gravely sandstones are interpreted as alluvial fan deposits. The basal polymictic orthoconglomerate passes up vertically into gravely sandstone, possibly indicating proximal to mid-fan sedimentation. The alluvial fan sedimentation passes up vertically into channel, point bars and flood-plain fines. The meandering river sedimentation is characterized by single and amalgamated multi-storey sandstone bodies. In places, the uppermost part of the Adigrat Sandstone Formation is represented by coal-bearing sediments possibly reflect lacustrine depositional environment. The medium-coarse-grained sandstone is a possible oil and gas reservoir, whilst the fine-grained sediments are a possible gas reservoir.

  4. Nile Delta

    Atmospheric Science Data Center

    2013-04-15

    article title:  The Nile River Delta     View Larger Image ... of eastern Africa. At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids ...

  5. Nile River, Lake Nasser, Aswan High Dam, Egypt

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The Aswan High Dam, 2.5 miles across and 364 feet high, (24.0N, 33.0E) completed in 1971, was constructed to supply cheap hydroelectric power to both Egypt and Sudan by impounding, controling and regulating the flood waters of the Nile River in Lake Nasser, the world's second largest artifical lake. The lake extends over 500 miles in length, covers an area of some 2,000 square miles and is as much as 350 feet deep at the face of the dam.

  6. Lake Nasser on Nile River in Egypt as seen from the Apollo 7 spacecraft

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Lake Nasser on the Nile River in southeastern United Arab Republic (Egypt) as seen from the Apollo 7 spacecraft during its 10th revolution of the earth. Photographed from an altitude of 130 nautical miles, at ground elapsed time of 14 hours and 56 minutes. Lake Nasser was created by the contruction of the Aswan Dam on the Nile.

  7. Lake Nasser on Nile River in Egypt as seen from the Apollo 7 spacecraft

    NASA Image and Video Library

    1968-10-12

    Lake Nasser on the Nile River in southeastern United Arab Republic (Egypt) as seen from the Apollo 7 spacecraft during its 10th revolution of the earth. Photographed from an altitude of 130 nautical miles, at ground elapsed time of 14 hours and 56 minutes. Lake Nasser was created by the contruction of the Aswan Dam on the Nile.

  8. Optimal operation of a multipurpose multireservoir system in the Eastern Nile River Basin

    NASA Astrophysics Data System (ADS)

    Goor, Q.; Halleux, C.; Mohamed, Y.; Tilmant, A.

    2010-07-01

    The upper Blue Nile River Basin in Ethiopia is a largely untapped resource despite its huge potential for hydropower generation and irrigated agriculture. Controversies exist as to whether the numerous infrastructural development projects that are on the drawing board in Ethiopia will generate positive or negative externalities downstream in Sudan and Egypt. This study attempts at 1) examining the (re-)operation of infrastructures, in particular the proposed reservoirs in Ethiopia and the High Aswan Dam and 2) assessing the economic benefits and costs associated with the storage infrastructures in Ethiopia and their spatial and temporal distribution. To achieve this, a basin-wide integrated hydro-economic model has been developed. The model integrates essential hydrologic, economic and institutional components of the river basin in order to explore both the hydrologic and economic consequences of various policy options and planned infrastructural projects. Unlike most of the deterministic economic-hydrologic models reported in the literature, a stochastic programming formulation has been adopted in order to: i) understand the effect of the hydrologic uncertainty on management decisions, ii) determine allocation policies that naturally hedge against the hydrological risk, and iii) assess the relevant risk indicators. The study reveals that the development of four mega dams in the upper part of the Blue Nile Basin would change the drawdown refill cycle of the High Aswan Dam. Should the operation of the reservoirs be coordinated, they would enable an average annual saving of at least 2.5 billion m3 through reduced evaporation losses from the Lake Nasser. Moreover, the new reservoirs (Karadobi, Beko-Abo, Mandaya and Border) in Ethiopia would have significant positive impacts on hydropower generation and irrigation in Ethiopia and Sudan: at the basin scale, the annual energy generation is boosted by 38.5 TWh amongst which 14.2 TWh due to storage. Moreover, the

  9. Optimal operation of a multipurpose multireservoir system in the Eastern Nile River Basin

    NASA Astrophysics Data System (ADS)

    Goor, Q.; Halleux, C.; Mohamed, Y.; Tilmant, A.

    2010-10-01

    The upper Blue Nile River Basin in Ethiopia is a largely untapped resource despite its huge potential for hydropower generation and irrigated agriculture. Controversies exist as to whether the numerous infrastructural development projects that are on the drawing board in Ethiopia will generate positive or negative externalities downstream in Sudan and Egypt. This study attempts at (1) examining the (re-)operation of infrastructures, in particular the proposed reservoirs in Ethiopia and the High Aswan Dam and (2) assessing the economic benefits and costs associated with the storage infrastructures in Ethiopia and their spatial and temporal distribution. To achieve this, a basin-wide integrated hydro-economic model has been developed. The model integrates essential hydrologic, economic and institutional components of the river basin in order to explore both the hydrologic and economic consequences of various policy options and planned infrastructural projects. Unlike most of the deterministic economic-hydrologic models reported in the literature, a stochastic programming formulation has been adopted in order to: (i) understand the effect of the hydrologic uncertainty on management decisions, (ii) determine allocation policies that naturally hedge against the hydrological risk, and (iii) assess the relevant risk indicators. The study reveals that the development of four mega dams in the upper part of the Blue Nile Basin would change the drawdown refill cycle of the High Aswan Dam. Should the operation of the reservoirs be coordinated, they would enable an average annual saving of at least 2.5 billion m3 through reduced evaporation losses from the Lake Nasser. Moreover, the new reservoirs (Karadobi, Beko-Abo, Mandaya and Border) in Ethiopia would have significant positive impacts on hydropower generation and irrigation in Ethiopia and Sudan: at the basin scale, the annual energy generation is boosted by 38.5 TWh amongst which 14.2 TWh due to storage. Moreover, the

  10. Explaining and forecasting interannual variability in the flow of the Nile River

    NASA Astrophysics Data System (ADS)

    Siam, M. S.; Eltahir, E. A. B.

    2015-03-01

    This study analyzes extensive data sets collected during the twentieth century and defines four modes of natural variability in the flow of the Nile River, identifying a new significant potential for improving predictability of floods and droughts. Previous studies have identified a significant teleconnection between the Nile flow and the eastern Pacific Ocean. El Niño-Southern Oscillation (ENSO) explains about 25% of the interannual variability in the Nile flow. Here, this study identifies a region in the southern Indian Ocean, with a similarly strong teleconnection to the Nile flow. Sea surface temperature (SST) in the region (50-80° E and 25-35° S) explains 28% of the interannual variability in the flow of the Nile River and, when combined with the ENSO index, the explained variability of the flow of the Nile River increases to 44%. In addition, during those years with anomalous SST conditions in both oceans, this study estimates that indices of the SSTs in the Pacific and Indian oceans can collectively explain up to 84% of the interannual variability in the flow of the Nile. Building on these findings, this study uses the classical Bayesian theorem to develop a new hybrid forecasting algorithm that predicts the Nile flow based on global model predictions of indices of the SST in the eastern Pacific and southern Indian oceans.

  11. Explaining and Forecasting Interannual Variability in the Flow of the Nile River

    NASA Astrophysics Data System (ADS)

    Eltahir, E. A.; Siam, M.

    2013-12-01

    The natural interannual variability in the flow of Nile River had a significant impact on the ancient civilizations and cultures that flourished on the banks of the river. Here, we analyze extensive data sets collected during the 20th century and define four modes of natural variability in the flow of Nile River, identifying a new significant potential for improving predictability of floods and droughts. Previous studies have identified a significant teleconnection between the Nile flow and the Eastern Pacific Ocean. El Niño-Southern Oscillation (ENSO) explains about 25% of the interannual variability in the Nile flow. Here, we identify, for the first time, a region in the southern Indian Ocean with similarly strong teleconnection to the Nile flow. Sea Surface Temperature (SST) in the region (60oE-90oE and 25oS-35oS) explains 28% of the interannual variability in the Nile flow. During those years with anomalous SST conditions in both Oceans, we estimate that indices of the SSTs in the Pacific and Indian Oceans can collectively explain up to 84% of the interannual variability in the flow of Nile. Building on these findings, we use classical Bayesian theorem to develop a new hybrid forecasting algorithm that predicts the Nile flow based on indices of the SST in the Eastern Pacific and Southern Indian Oceans.

  12. Explaining and forecasting interannual variability in the flow of the Nile River

    NASA Astrophysics Data System (ADS)

    Siam, M. S.; Eltahir, E. A. B.

    2014-05-01

    The natural interannual variability in the flow of Nile River had a significant impact on the ancient civilizations and cultures that flourished on the banks of the river. This is evident from stories in the Bible and Koran, and from the numerous Nilometers discovered near ancient temples. Here, we analyze extensive data sets collected during the 20th century and define four modes of natural variability in the flow of Nile River, identifying a new significant potential for improving predictability of floods and droughts. Previous studies have identified a significant teleconnection between the Nile flow and the Eastern Pacific Ocean. El Niño-Southern Oscillation (ENSO) explains about 25% of the interannual variability in the Nile flow. Here, we identify, for the first time, a region in the southern Indian Ocean with similarly strong teleconnection to the Nile flow. Sea Surface Temperature (SST) in the region (50-80° E and 25-35° S) explains 28% of the interannual variability in the Nile flow. During those years with anomalous SST conditions in both Oceans, we estimate that indices of the SSTs in the Pacific and Indian Oceans can collectively explain up to 84% of the interannual variability in the flow of Nile. Building on these findings, we use classical Bayesian theorem to develop a new hybrid forecasting algorithm that predicts the Nile flow based on global models predictions of indices of the SST in the Eastern Pacific and Southern Indian Oceans.

  13. An Integrated Hydrological and Water Management Study of the Entire Nile River System - Lake Victoria to Nile Delta

    NASA Technical Reports Server (NTRS)

    Habib, Shahid; Zaitchik, Benjamin; Alo, Clement; Ozdogan, Mutlu; Anderson, Martha; Policelli, Fritz

    2011-01-01

    The Nile basin River system spans 3 million km(exp 2) distributed over ten nations. The eight upstream riparian nations, Ethiopia, Eretria, Uganda, Rwanda, Burundi, Congo, Tanzania and Kenya are the source of approximately 86% of the water inputs to the Nile, while the two downstream riparian countries Sudan and Egypt, presently rely on the river's flow for most of the their needs. Both climate and agriculture contribute to the complicated nature of Nile River management: precipitation in the headwaters regions of Ethiopia and Lake Victoria is variable on a seasonal and inter-annual basis, while demand for irrigation water in the arid downstream region is consistently high. The Nile is, perhaps, one of the most difficult trans-boundary water issue in the world, and this study would be the first initiative to combine NASA satellite observations with the hydrologic models study the overall water balance in a to comprehensive manner. The cornerstone application of NASA's Earth Science Research Results under this project are the NASA Land Data Assimilation System (LDAS) and the USDA Atmosphere-land Exchange Inverse (ALEXI) model. These two complementary research results are methodologically independent methods for using NASA observations to support water resource analysis in data poor regions. Where an LDAS uses multiple sources of satellite data to inform prognostic simulations of hydrological process, ALEXI diagnoses evapotranspiration and water stress on the basis of thermal infrared satellite imagery. Specifically, this work integrates NASA Land Data Assimilation systems into the water management decision support systems that member countries of the Nile Basin Initiative (NBI) and Regional Center for Mapping of Resources for Development (RCMRD, located in Nairobi, Kenya) use in water resource analysis, agricultural planning, and acute drought response to support sustainable development of Nile Basin water resources. The project is motivated by the recognition that

  14. Hydrochemical evaluation of groundwater in the Blue Nile Basin, eastern Sudan, using conventional and multivariate techniques

    NASA Astrophysics Data System (ADS)

    Hussein, Mohammed Tahir

    Hydrochemical evaluation of groundwater systems can be carried out using conventional and multivariate techniques, namely cluster, factor analyses and others such as correspondence analysis. The main objective of this study is to investigate the groundwater quality in the Blue Nile basin of eastern Sudan, and to workout a hydrochemical evaluation for the aquifer system. Conventional methods and multivariate techniques were applied to achieve these goals. Two water-bearing layers exist in the study area: the Nubian Sandstone Formation and the Al-Atshan Formation. The Nubian aquifer is recharged mainly from the Blue Nile and Dinder Rivers through lateral subsurface flow and through direct rainfall in outcrop areas. The Al-Atshan aquifer receives water through underground flow from River Rahad and from rainfall infiltration. The prevailing hydrochemical processes are simple dissolution, mixing, partial ion exchange and ion exchange. Limited reverse ion exchange has been witnessed in the Nubian aquifer. Three factors control the overall mineralization and water quality of the Blue Nile Basin. The first factor includes high values of total dissolved solids, electrical conductivity, sodium, potassium, chloride, bicarbonate, sulphate and magnesium. The second factor includes calcium and pH. The third factor is due to fluoride concentration in the groundwater. The study highlights the descriptive capabilities of conventional and multivariate techniques as effective tools in groundwater quality evaluation. Une étude hydrochimique de systèmes aquifères a pu être réalisée au moyen des techniques conventionnelles et multidimensionnelles, telles que les analyses de cluster et factorielles, ainsi que d'autres comme l'analyse des correspondances. Le principal objectif de ce travail est d'étudier la qualité des eaux souterraines du bassin du Nil bleu au Soudan oriental, et de réaliser une évaluation hydrochimique du système aquifère. Des méthodes conventionnelles et

  15. Using a Water Balance Model to Bound Potential Irrigation Development in the Upper Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Jain Figueroa, A.; McLaughlin, D.

    2016-12-01

    The Grand Ethiopian Renaissance Dam (GERD), on the Blue Nile is an example of water resource management underpinning food, water and energy security. Downstream countries have long expressed concern about water projects in Ethiopia because of possible diversions to agricultural uses that could reduce flow in the Nile. Such diversions are attractive to Ethiopia as a partial solution to its food security problems but they could also conflict with hydropower revenue from GERD. This research estimates an upper bound on diversions above the GERD project by considering the potential for irrigated agriculture expansion and, in particular, the availability of water and land resources for crop production. Although many studies have aimed to simulate downstream flows for various Nile basin management plans, few have taken the perspective of bounding the likely impacts of upstream agricultural development. The approach is to construct an optimization model to establish a bound on Upper Blue Nile (UBN) agricultural development, paying particular attention to soil suitability and seasonal variability in climate. The results show that land and climate constraints impose significant limitations on crop production. Only 25% of the land area is suitable for irrigation due to the soil, slope and temperature constraints. When precipitation is also considered only 11% of current land area could be used in a way that increases water consumption. The results suggest that Ethiopia could consume an additional 3.75 billion cubic meters (bcm) of water per year, through changes in land use and storage capacity. By exploiting this irrigation potential, Ethiopia could potentially decrease the annual flow downstream of the UBN by 8 percent from the current 46 bcm/y to the modeled 42 bcm/y.

  16. A Journey on Three Rivers: The Nile, The Rhine, The Mississippi.

    ERIC Educational Resources Information Center

    Allen, Anita

    1996-01-01

    Focuses on the Nile, the Rhine, and the Mississippi, the greatest rivers of Africa, Europe, and North America, respectively. Highlights the rich diversity of subjects associated with rivers including geography, history, literature, and art. Includes 12 learning activities for each river. (MJP)

  17. A Journey on Three Rivers: The Nile, The Rhine, The Mississippi.

    ERIC Educational Resources Information Center

    Allen, Anita

    1996-01-01

    Focuses on the Nile, the Rhine, and the Mississippi, the greatest rivers of Africa, Europe, and North America, respectively. Highlights the rich diversity of subjects associated with rivers including geography, history, literature, and art. Includes 12 learning activities for each river. (MJP)

  18. Apollo 9 Mission image - United Arab Republic,Nile River,Red Sea and Aswan Dam

    NASA Image and Video Library

    1969-03-03

    Oblique Earth Observation taken by the Apollo 9 crew. View is the United Arab Republic,the Nile River,The Red Sea and the Aswan Dam. Film magazine was E,film type was SO-368 Ektachrome with 0.460 - 0.710 micrometers film / filter transmittance response and haze filter,80mm lens. Latitude was 19.38 N by Longitude 30.24 E, Overlap was 50%, Altitude was 97 nautical miles and cloud cover was 5%.

  19. A new model of river dynamics, hydroclimatic change and human settlement in the Nile Valley derived from meta-analysis of the Holocene fluvial archive

    NASA Astrophysics Data System (ADS)

    Macklin, Mark G.; Toonen, Willem H. J.; Woodward, Jamie C.; Williams, Martin A. J.; Flaux, Clément; Marriner, Nick; Nicoll, Kathleen; Verstraeten, Gert; Spencer, Neal; Welsby, Derek

    2015-12-01

    In the Nile catchment, a growing number of site- and reach-based studies employ radiocarbon and, more recently, OSL dating to reconstruct Holocene river histories, but there has been no attempt to critically evaluate and synthesise these data at the catchment scale. We present the first meta-analysis of published and publically available radiocarbon and OSL dated Holocene fluvial units in the Nile catchment, including the delta region, and relate this to changing climate and river dynamics. Dated fluvial units are separated both geographically (into the Nile Delta and White, Blue, and Desert Nile sub-regions) and into depositional environment (floodplain and palaeochannel fills). Cumulative probability density frequency (CPDF) plots of floodplain and palaeochannel units show a striking inverse relationship during the Holocene, reflecting abrupt (<100 years) climate-related changes in flooding regime. The CPDF plot of dated floodplain units is interpreted as a record of over-bank river flows, whilst the CPDF plot of palaeochannel units reflect periods of major flooding associated with channel abandonment and contraction, as well as transitions to multi-centennial length episodes of greater aridity and low river flow. This analysis has identified major changes in river flow and dynamics in the Nile catchment with phases of channel and floodplain contraction at c. 6150-5750, 4400-4150, 3700-3450, 2700-2250, 1350-900, 800-550 cal. BC and cal. AD 1600, timeframes that mark shifts to new hydrological and geomorphological regimes. We discuss the impacts of these changing hydromorphological regimes upon riverine civilizations in the Nile Valley.

  20. Trend analysis of runoff and sediment fluxes in the Upper Blue Nile basin: A combined analysis of statistical tests, physically-based models and landuse maps

    NASA Astrophysics Data System (ADS)

    Gebremicael, T. G.; Mohamed, Y. A.; Betrie, G. D.; van der Zaag, P.; Teferi, E.

    2013-03-01

    SummaryThe landuse/cover changes in the Ethiopian highlands have significantly increased the variability of runoff and sediment fluxes of the Blue Nile River during the last few decades. The objectives of this study were (i) to understand the long-term variations of runoff and sediment fluxes using statistical models, (ii) to interpret and corroborate the statistical results using a physically-based hydrological model, Soil and Water Assessment Tool (SWAT), and (iii) to validate the interpretation of SWAT results by assessing changes of landuse maps. Firstly, Mann-Kendall and Pettitt tests were used to test the trends of Blue Nile flow (1970-2009) and sediment load (1980-2009) at the outlet of the Upper Blue Nile basin at El Diem station. These tests showed statistically significant increasing trends of annual stream flow, wet season stream flow and sediment load at 5% confidence level. The dry season flow showed a significant decrease in the trend. However, during the same period the annual rainfall over the basin showed no significant trends. The results of the statistical tests were sensitive to the time domain. Secondly, the SWAT model was used to simulate the runoff and sediment fluxes in the early 1970s and at the end of the time series in 2000s in order to interpret the physical causes of the trends and corroborate the statistical results. A comparison of model parameter values between the 1970s and 2000s shows significant change, which could explain catchment response changes over the 28 years of record. Thirdly, a comparison of landuse maps of 1970s against 2000s shows conversion of vegetation cover into agriculture and grass lands over wide areas of the Upper Blue Nile basin. The combined results of the statistical tests, the SWAT model, and landuse change detection are consistent with the hypothesis that landuse change has caused a significant change of runoff and sediment load from the Upper Blue Nile during the last four decades. This is an important

  1. Interaction of surface water and groundwater in the Nile River basin: isotopic and piezometric evidence

    NASA Astrophysics Data System (ADS)

    Kebede, Seifu; Abdalla, Osman; Sefelnasr, Ahmed; Tindimugaya, Callist; Mustafa, Osman

    2017-05-01

    Past discussions around water-resources management and development in the River Nile basin disregard groundwater resources from the equation. There is an increasing interest around factoring the groundwater resources as an integral part of the Nile Basin water resources. This is hampered by knowledge gap regarding the groundwater resources dynamics (recharge, storage, flow, quality, surface-water/groundwater interaction) at basin scale. This report provides a comprehensive analysis of the state of surface-water/groundwater interaction from the headwater to the Nile Delta region. Piezometric and isotopic (δ18O, δ2H) evidence reveal that the Nile changes from a gaining stream in the headwater regions to mostly a loosing stream in the arid lowlands of Sudan and Egypt. Specific zones of Nile water leakage to the adjacent aquifers is mapped using the two sources of evidence. Up to 50% of the surface-water flow in the equatorial region of the Nile comes from groundwater as base flow. The evidence also shows that the natural direction and rate of surface-water/groundwater interaction is largely perturbed by human activities (diversion, dam construction) particularly downstream of the Aswan High Dam in Egypt. The decrease in discharge of the Nile River along its course is attributed to leakage to the aquifers as well as to evaporative water loss from the river channel. The surface-water/groundwater interaction occurring along the Nile River and its sensitivity to infrastructure development calls for management strategies that account groundwater as an integral part of the Nile Basin resources.

  2. Interaction of surface water and groundwater in the Nile River basin: isotopic and piezometric evidence

    NASA Astrophysics Data System (ADS)

    Kebede, Seifu; Abdalla, Osman; Sefelnasr, Ahmed; Tindimugaya, Callist; Mustafa, Osman

    2016-12-01

    Past discussions around water-resources management and development in the River Nile basin disregard groundwater resources from the equation. There is an increasing interest around factoring the groundwater resources as an integral part of the Nile Basin water resources. This is hampered by knowledge gap regarding the groundwater resources dynamics (recharge, storage, flow, quality, surface-water/groundwater interaction) at basin scale. This report provides a comprehensive analysis of the state of surface-water/groundwater interaction from the headwater to the Nile Delta region. Piezometric and isotopic (δ18O, δ2H) evidence reveal that the Nile changes from a gaining stream in the headwater regions to mostly a loosing stream in the arid lowlands of Sudan and Egypt. Specific zones of Nile water leakage to the adjacent aquifers is mapped using the two sources of evidence. Up to 50% of the surface-water flow in the equatorial region of the Nile comes from groundwater as base flow. The evidence also shows that the natural direction and rate of surface-water/groundwater interaction is largely perturbed by human activities (diversion, dam construction) particularly downstream of the Aswan High Dam in Egypt. The decrease in discharge of the Nile River along its course is attributed to leakage to the aquifers as well as to evaporative water loss from the river channel. The surface-water/groundwater interaction occurring along the Nile River and its sensitivity to infrastructure development calls for management strategies that account groundwater as an integral part of the Nile Basin resources.

  3. STS-57 Earth observation of the Eastern Mediterranean, Nile River, Asia Minor

    NASA Image and Video Library

    1993-07-01

    STS057-73-075 (21 June-1 July 1993) --- Eastern Mediterranean from an unusually high vantage point over the Nile River, this north-looking view shows not only the eastern Mediterranean but also the entire landmass of Asia Minor, with the Black Sea dimly visible at the horizon. Many of the Greek islands can be seen in the Aegean Sea (top left), off the coast of Asia Minor. Cyprus is visible under atmospheric dust in the northeast corner of the Mediterranean. The dust cloud covers the east end of the Mediterranean, its western edge demarcated by a line that cuts the center of the Nile Delta. This dust cloud originated far to the west, in Algeria, and moved northeast over Sicily, southern Italy, and Greece. Part of the cloud then moved on over the Black Sea, but another part swerved southward back towards Egypt. A gyre of clouds in the southeast corner of the Mediterranean indicates a complementary counterclockwise (cyclonic) circulation of air. The Euphrates River appears as a thin green line (upper right) in the yellow Syrian Desert just south of the blue-green mountains of Turkey. The Dead Sea (lower right) lies in a rift valley which extends north into Turkey and south thousands of miles down the Gulf of Aqaba, the Red Sea, and on through East Africa. The straight international boundary between Israel and Egypt (where the coastline angles) is particularly clear in this view, marked by the thicker vegetation on the Israeli side of the border. The green delta of the Nile River appears in the foreground, with the great conurbation of Cairo seen as a gray area at the apex of the triangle. Most of Egypt's 52 million inhabitants live in the delta. On the east side of the delta, the Suez Canal is visible. On the western corner of the delta lies the ancient city of Alexandria, beside the orange and white salt pans. The World War II battlesite El Alamein lies on the coast.

  4. An electropolymerized Nile Blue sensing film-based nitrite sensor and application in food analysis.

    PubMed

    Chen, Xiaowei; Wang, Fang; Chen, Zilin

    2008-08-15

    This paper reports a poly-Nile Blue (PNB) sensing film based electrochemical sensor and the application in food analysis as a possible alternative for electrochemical detection of nitrite. The PNB-modified electrode in the sensor was prepared by in situ electropolymerization of Nile Blue at a prepolarized glassy carbon (GC) electrode and then characterized by cyclic voltammetry (CV) and pulse voltammetry in phosphate buffer (pH 7.1). Several key operational parameters affecting the electrochemical response of PNB sensing film were examined and optimized, such as polarization time, PNB film thickness and electrolyte pH values. As the electroactive PNB sensing film provides plenty of active sites for anodic oxidation of nitrite, the nitrite sensor exhibited high performance including high sensitivity, low detection limit, simple operation and good stability at the optimized conditions. The nitrite sensor revealed good linear behavior in the concentration range from 5.0x10(-7) mol L(-1) to 1.0x10(-4) mol L(-1) for the quantitative analysis of nitrite anion with a limit of detection of 1.0x10(-7) mol L(-1). Finally, the application in food analysis using sausage as testing samples was investigated and the results were consistent with those obtained by standard spectrophotometric method.

  5. The question of Sudan: a hydro-economic optimization model for the Sudanese Blue Nile

    NASA Astrophysics Data System (ADS)

    Satti, S.; Zaitchik, B.; Siddiqui, S.

    2015-05-01

    The effects of development and the uncertainty of a changing climate in eastern Africa pose myriad challenges for water managers along the Blue Nile. Sudan's large irrigation potential, hydroelectric dams, and prime location within the basin mean that Sudan's water management decisions will have great social, economic and political implications for the region. At the same time, Sudan's water use options are constrained by tradeoffs between upstream irrigation developments and downstream hydropower facilities as well as by the country's commitments under existing or future transboundary water sharing agreements. Here, we present a model that can be applied to evaluate optimal allocation of surface water resources to irrigation and hydropower in the Sudanese portion of the Blue Nile. Hydrologic inputs are combined with agronomic and economic inputs to formulate an optimization model within the General Algebraic Modeling System (GAMS). A sensitivity analysis is performed by testing model response to a range of economic conditions and to changes in the volume and timing of hydrologic flows. Results indicate that changing hydroclimate inputs have the capacity to greatly influence the productivity of Sudan's water resource infrastructure. Results also show that the economically optimal volume of water consumption, and thus the importance of existing treaty constraints, is sensitive to the perceived value of agriculture relative to electricity as well as to changing hydrological conditions.

  6. Shifting sediment sources in the world's longest river: A strontium isotope record for the Holocene Nile

    NASA Astrophysics Data System (ADS)

    Woodward, Jamie; Macklin, Mark; Fielding, Laura; Millar, Ian; Spencer, Neal; Welsby, Derek; Williams, Martin

    2015-12-01

    We have reconstructed long-term shifts in catchment sediment sources by analysing, for the first time, the strontium (Sr) and neodymium (Nd) isotope composition of dated floodplain deposits in the Desert Nile. The sediment load of the Nile has been dominated by material from the Ethiopian Highlands for much of the Holocene, but tributary wadis and aeolian sediments in Sudan and Egypt have also made major contributions to valley floor sedimentation. The importance of these sources has shifted dramatically in response to global climate changes. During the African Humid Period, before c. 4.5 ka, when stronger boreal summer insolation produced much higher rainfall across North Africa, the Nile floodplain in northern Sudan shows a tributary wadi input of 40-50%. Thousands of tributary wadis were active at this time along the full length of the Saharan Nile in Egypt and Sudan. As the climate became drier after 4.5 ka, the valley floor shows an abrupt fall in wadi inputs and a stronger Blue Nile/Atbara contribution. In the arid New Kingdom and later periods, in palaeochannel fills on the margins of the valley floor, aeolian sediments replace wadi inputs as the most important secondary contributor to floodplain sedimentation. Our sediment source data do not show a measurable contribution from the White Nile to the floodplain deposits of northern Sudan over the last 8500 years. This can be explained by the distinctive hydrology and sediment delivery dynamics of the upper Nile basin. High strontium isotope ratios observed in delta and offshore records - that were previously ascribed to a stronger White Nile input during the African Humid Period - may have to be at least partly reassessed. Our floodplain Sr records also have major implications for bioarchaeologists who carry out Sr isotope-based investigations of ancient human remains in the Nile Valley because the isotopic signature of Nile floodplain deposits has shifted significantly over time.

  7. Methods for interfacing IPCC climate change scenarios with higher resolution watershed management models in the Ethiopian Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Easton, Z. M.; MacAlister, C.; Fuka, D. R.

    2013-12-01

    As much as 90% of the Nile River flow that reaches Egypt originates in the Highlands of the Ethiopian Blue Nile Basin. This imbalance in water availability poses a threat to water security in the region, and could be severely impacted by projected climate change. This analysis coupled hydrodynamic/watershed models with the Intergovernmental Panel on Climate Change (IPCC) AR4 climate change scenarios to assess the potential impact on water resources and sediment dynamics. Specific AR4 scenarios include the A1B, B1, B2 and COMMIT, which were used to force the baseline hydrodynamic models calibrated against 1979-2011 streamflow for 20 sub-watersheds in the Tana and Beles basins. Transfer functions were developed to distribute the model parameters from the calibrated sub-watersheds to un-gauged portions of the basins based on a similarity index of hydrologic response units. We analyzed the scenario in two manners: first we ran all of the seven individual Global Circulation Model results in the IPCC AR4 report though our watershed models to asses the potential spread of climate change predictions; then we assessed the mean value produced for each IPCC AR4 scenario to better estimate convergence. Results indicate that the Tana basin is expected to experience an increase in mean annual flow. The Beles basin is predicted to experience a small decrease in mean annual flow. Sediment concentrations in the Tana basin increase proportionally more than the flow increase. Interestingly, and perhaps counter to what might be expected for a decrease in flow in the Beles basin, sediment concentrations increase.

  8. Building climate resilience in the Blue Nile/Abay Highlands: Part II-arole for earth system sciences

    USDA-ARS?s Scientific Manuscript database

    The Blue Nile (Abay) Highlands of Ethiopia are characterized by significant interannual climate variability, dissected topography and associated local climate contrasts, erosive rains and erodible soils, and intense land pressure due to an increasing population and an economy that is almost entirely...

  9. Modification of Blue LED using Organic-Inorganic Hybrid Polymer Doped with Nile Red for Artificial Lighting of Photosynthesis

    NASA Astrophysics Data System (ADS)

    Syakir, Norman; Syarifudin, Fahmi; Hidayat, Sahrul; Fitrilawati

    2017-07-01

    The photosynthesis process of chlorophyll absorbs only the light with wavelength in the blue and red ranges. The absorption peak of the chlorophyll-A is at 428 nm and 660 nm, while absorption peak of chlorophyll-B is at 453 nm and 643 nm. We report the modification of blue LED using hybrid polymer doped with Nile Red. In order to match the total absorption spectra of chlorophyll-A and chlorophyll-B, the emission spectrum of the modified blue LED was taken out by using the wavelength conversion material. We modified the blue LED by covering the blue LED of 450 nm as excitation source with precursor of red wavelength conversion material. The red wavelength conversion material was prepared by doped precursor of TMSPMA hybrid polymer with organic phosphor of Nile Red. The precursor of hybrid polymer was synthesized using sol-gel process and then it was doped with 0.1% Nile Red. In order to freeze the precursor of these conversion material, we employed UV photopolymerization process. The modified blue LED has two emission peaks, which are at 448 nm (blue emission) and at 651 nm (red emission). The optimum spectrum profile of the modified blue LED has similar range as the total absorption spectra of chlorophyll-A and chlorophyll-B that obtain using Nile Red with the mass of 2.9 μg and the driven current of 60 mA. This result has a potential application for the artificial lighting in the photosynthesis process of horticultures at indoor plantation.

  10. An outbreak of bovine trypanosomiasis in the Blue Nile State, Sudan

    PubMed Central

    2011-01-01

    Background In this paper, we report an outbreak of bovine trypanosomiasis in Kurmuk District, Blue Nile State, Sudan that involved an infection with four Trypanosoma species in cattle. The outbreak occurred in June 2010 when indigenous cattle, mainly Kenana and Fulani breed types, crossed the national Sudanese border to Ethiopia and returned. A veterinarian was notified of massive deaths in the cattle populations that recently came from Ethiopia. All animals involved in the outbreak were from the nomadic Fulani group and resident local cattle were not infected and no death has been reported among them. A total of 210 blood samples were collected from the ear vein of cattle. A few samples were also collected from other domestic animals species. Parasitological examinations including hematocrit centrifugation techniques (HCT) and Giemsa-stained thin blood films were carried out. ITS1-PCR, which provides a multi-species-specific diagnosis in a single PCR, was performed. Findings Parasitological examinations revealed that 43% (91/210) of the affected cattle population was infected with two morphologically distinct trypanosomes. Seventy animals (33.3%) were infected with T. vivax and twenty one (10%) with T. congolense. In contrast, ITS1-PCR was able to identify four Trypanosoma species namely T. vivax, T. congolense, T. simiae and T. brucei in 56.7% (80/141). T. brucei showed the highest prevalence of 36.9% (52/141) and the lowest 19% (27/141) was displayed by T. congolense. Furthermore, and because ITS1-PCR could not differentiate between T. brucei subspecies, serum resistance-associated (SRA) gene based PCR was used to detect the human T. brucei rhodesiense in T. brucei positive samples. None of the samples was shown positive for T. b. rhodesiense. The identity of the 400 bp PCR product originating from T. simiae, was further confirmed by sequencing and subsequent phylogenetic analysis. Conclusions The outbreak of bovine trypanosomiasis occurred in the Blue Nile

  11. Placental malaria and its effect on pregnancy outcomes in Sudanese women from Blue Nile State.

    PubMed

    Omer, Samia A; Idress, Hagir E; Adam, Ishag; Abdelrahim, Mutasim; Noureldein, Ali N; Abdelrazig, Abdelrahim M; Elhassan, Mohammed O; Sulaiman, Suad M

    2017-09-16

    Malaria infection during pregnancy can result in placental malaria and is associated with adverse pregnancy outcomes particularly among primigravidae. The aim of this study was to assess the prevalence and risk factors for placental malaria and its effect on pregnancy outcomes in Blue Nile state, Sudan. A cross-sectional hospital-based study was conducted consecutively during January 2012-December 2015 in three main hospitals in Blue Nile State, Sudan. At delivery, peripheral and placental blood samples were collected from consenting women. Finger prick blood was used for preparation of peripheral smears and for haemoglobin measurement. Smears were stained with Giemsa and examined microscopically for malaria parasites. Pregnancy outcomes in association to placental malaria were investigated. A total of 1149 mothers and their newborns were recruited. The mean (SD) of the age was 23.3 (5.2) years. Detection of malaria parasites was confirmed in 37.8% of the peripheral blood films and 59.3% of the placental films with Plasmodium falciparum as the only species detected. In multivariate analysis, younger age ≤23.2 years old (AOR = 3.2, 95% CI 1.9-5.5; P < 0.001), primiparae (AOR = 3.9, CI 2.1-7.6; P < 0.001), secundiparae (AOR = 2.8, 95% CI 1.5-5.1; P < 0.001, no antenatal care (ANC) visits (AOR = 11.9, 95% CI 7.8-18.1; P < 0.001) and not using bed nets (AOR = 3.5, 95% CI 1.7-6.8; P < 0.001) were risk factors for placental malaria. Education and residence were not associated with placental malaria infection. Placental malaria was significantly associated with maternal anaemia (AOR = 41.6, 95% CI 23.3-74.4; P < 0.001) and low birth weight (LBW) (AOR = 25.2, 95% CI 15.1-41.3; P < 0.001). During the study, there was a high prevalence of placental malaria in Blue Nile State-Sudan, as the enhanced control activities were not practiced, leading to adverse pregnancy outcomes, such as maternal anaemia and LBW.

  12. Conflicts of Shared Resources: A Case Study of River Nile

    DTIC Science & Technology

    2012-03-22

    as Lake Kivu. Rwanda joined the earlier Nile basin project, Hydromet , in 1967, with the support on the UNDP. 18 Although the country does not...operation Hydromet . In 1967, with the assistance of the United Nations Development Program (UNDP) and the World Meteorological Organization (WMO), Egypt...Kenya, Sudan, Tanzania and Uganda launched the Hydromet Survey project to regulate the water level of the Nile.”30 Rwanda joined later while Ethiopia

  13. Nile blue fluorescence signals from cut single muscle fibers under voltage or current clamp conditions

    PubMed Central

    1978-01-01

    A method is presented for recording extrinsic optical signals from segments of single skeletal muscle fibers under current or voltage clamp conditions. Such segments, which are cut from intact fibers, are maintained in a relaxed state, while exhbiting otherwise normal physiological properties, including healthy delayed rectifier currents. Extrinsic fluorescence changes are demonstrated, using the permeant potentiometric probe, Nile Blue A. These changes vary nonlinearly with the controlled surface membrane potential, in a manner which suggests that they arise from potential changes in the sarcoplasmic reticulum. According to this interpretation, a simple model based on the gating charge movement implicated in excitation-contraction coupling, provides a self-consistent description of the voltage dependence of the signal that requires no additional parameters. PMID:310445

  14. Evaluation of regional climate model simulations of rainfall over the Upper Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Alemseged, Tamiru Haile; Tom, Rientjes

    2015-07-01

    Climate change impact and adaptation studies can benefit from an enhanced understanding about the performance of individual as well as ensemble simulations of climate models. Studies that evaluate downscaled simulations of General Circulation Models (GCMs) by Regional Climate Models (RCMs) for African basins are noticeably missing. Recently, the Coordinated Regional Climate Downscaling Experiment (CORDEX) initiative has made multiple RCMs' outputs available for end users across the African continent. Before climate simulations receive applications in impact and adaptation studies, accuracy of the simulation results has to be evaluated. In this study, the rainfall accuracy of eight independent GCMs at a wide range of time scales over the Upper Blue Nile Basin (UBN) in Ethiopia is evaluated. The reference data for performance assessment was obtained from the rain gauge network of the National Meteorological Agency of Ethiopia (http://www.ethiomet.gov.et/)

  15. Personnel scheduling using an integer programming model- an application at Avanti Blue-Nile Hotels.

    PubMed

    Kassa, Biniyam Asmare; Tizazu, Anteneh Eshetu

    2013-01-01

    In this paper, we report perhaps a first of its kind application of management science in the Ethiopian hotel industry. Avanti Blue Nile Hotels, a newly established five star hotel in Bahir Dar, is the company for which we developed an integer programming model that determines an optimal weekly shift schedule for the Hotel's engineering department personnel while satisfying several constraints including weekly rest requirements per employee, rest requirements between working shifts per employee, required number of personnel per shift, and other constraints. The model is implemented on an excel solver routine. The model enables the company's personnel department management to develop a fair personnel schedule as needed and to effectively utilize personnel resources while satisfying several technical, legal and economic requirements. These encouraging achievements make us optimistic about the gains other Ethiopian organizations can amass by introducing management science approaches in their management planning and decision making systems.

  16. Climate Change Impact on Variability of Rainfall Intensity in Upper Blue Nile Basin, Ethiopia

    NASA Astrophysics Data System (ADS)

    Worku, L. Y.

    2015-12-01

    Extreme rainfall events are major problems in Ethiopia with the resulting floods that usually could cause significant damage to agriculture, ecology, infrastructure, disruption to human activities, loss of property, loss of lives and disease outbreak. The aim of this study was to explore the likely changes of precipitation extreme changes due to future climate change. The study specifically focuses to understand the future climate change impact on variability of rainfall intensity-duration-frequency in Upper Blue Nile basin. Precipitations data from two Global Climate Models (GCMs) have been used in the study are HadCM3 and CGCM3. Rainfall frequency analysis was carried out to estimate quantile with different return periods. Probability Weighted Method (PWM) selected estimation of parameter distribution and L-Moment Ratio Diagrams (LMRDs) used to find the best parent distribution for each station. Therefore, parent distributions for derived from frequency analysis are Generalized Logistic (GLOG), Generalized Extreme Value (GEV), and Gamma & Pearson III (P3) parent distribution. After analyzing estimated quantile simple disaggregation model was applied in order to find sub daily rainfall data. Finally the disaggregated rainfall is fitted to find IDF curve and the result shows in most parts of the basin rainfall intensity expected to increase in the future. As a result of the two GCM outputs, the study indicates there will be likely increase of precipitation extremes over the Blue Nile basin due to the changing climate. This study should be interpreted with caution as the GCM model outputs in this part of the world have huge uncertainty.

  17. Reservoir system expansion scheduling under conflicting interests - A Blue Nile application

    NASA Astrophysics Data System (ADS)

    Geressu, Robel; Harou, Julien

    2017-04-01

    New water resource developments are facing increasing resistance due to their real and perceived potential to affect existing systems' performance negatively. Hence, scheduling new dams in multi-reservoir systems requires considering conflicting performance objectives to minimize impacts, create consensus among wider stakeholder groups and avoid conflict. However, because of the large number of alternative expansion schedules, planning approaches often rely on simplifying assumptions such as the appropriate gap between expansion stages or less flexibility in reservoir release rules than what is possible. In this study, we investigate the extent to which these assumptions could limit our ability to find better performing alternatives. We apply a many-objective sequencing approach to the proposed Blue Nile hydropower reservoir system in Ethiopia to find best investment schedules and operating rules that maximize long-term discounted net benefits, downstream releases and energy generation during reservoir filling periods. The system is optimized using 30 realizations of stochastically generated streamflow data, statistically resembling the historical flow. Results take the form of Pareto-optimal trade-offs where each point on the curve or surface represents a combination of new reservoirs, their implementation dates and operating rules. Results show a significant relationship between detail in operating rule design (i.e., changing operating rules as the multi-reservoir expansion progresses) and the system performance. For the Blue Nile, failure to optimize operating rules in sufficient detail could result in underestimation of the net worth of the proposed investments by up to 6 billion USD if a development option with low downstream impact (slow filling of the reservoirs) is to be implemented.

  18. Quantifying Knick Point Migration Rates Related to the Messinian Crisis. The Case of the Nile River

    NASA Astrophysics Data System (ADS)

    Stüwe, Kurt; Pucher, Christoph; Robl, Jörg; Hergarten, Stefan

    2016-04-01

    The Messinian crisis is a temporally well-constrained period between 5.3 my and 5.9 my, when the strait of Gibraltar was tectonically closed and the Mediterranean Sea had consequently desiccated. This dramatic base level drop by about 1500 vertical meters had a profound influence on the geomorphic evolution of the major drainages surrounding the Mediterranean basin. In particular, it caused substantial knickpoints in the major rivers including the Rhone, the Ebro, the Po and the Nile. While the knickpoints of the Rhone and Ebro have been studied previously and the knickpoints created by the Po may lie today underneath the Po plains, the knickpoint and its migration along the Nile has not been studied and would have migrated along its current river channel. In this contribution we focus on numerical modelling of the knickpoint migration in the Nile and use our modelling results in comparison with the present day morphological analyses of the river to constrain absolute migration rates. We suspect that the first Nile cataract near Assuan, some 1000 km upstream of today's river mouth may be the relict of the Messinian salinity crisis making it to one of the fastest migrating knickpoints in the world.

  19. Discharge of the nile river: a barometer of short-period climate variation.

    PubMed

    Riehl, H; Meitín, J

    1979-12-07

    Eight events of climate variation with durations of the order of 100 years have been found in the history of annual Nile River discharge dating from the year 622. They cease during the "little climatic optimum" in the North Atlantic and then reappear and intensify; this behavior suggests that control is from the belt of the polar westerlies.

  20. Tradeoff Analysis Between Economic Development and Climate Change Adaptation Strategies for River Nile Basin Water Resources

    USDA-ARS?s Scientific Manuscript database

    Recent Intergovernmental Panel on Climate Change (IPCC) briefings have declared that the growing population in the Nile river basin region (about 160 million, or 57% of the entire population of the basin’s ten riparian countries) is at risk of water scarcity. Adjustment strategies in response to cl...

  1. Occurrence of pesticides in fish tissues, water and soil sediment from Manzala Lake and River Nile.

    PubMed

    Osfor, M M; Abd el Wahab, A M; el Dessouki, S A

    1998-02-01

    Pesticides constitute the major source of potential environmental hazard to man and animal as they are present and concentrated in the food chain. This study was conducted on 136 samples of water, sediment and fish for detection and determination of pesticide residues in this ecosystem. Highly significant differences were found in levels of Indian, heptachlor, endrin, dieldrin, P,P'-DDE and propoxur in River Nile water when compared with that of Manzala Lake. Levels of Indian, endrin, malathion and diazinon were significantly higher in soil sediment of Manzala Lake, while the levels of heptachlor, aldrine, P,P'-DDE, DDT, parathion, propoxur and zectran were significantly higher in soil sediment of River Nile. Boury fish of Manzala Lake contained higher levels of heptachlor, aldrin, P,P'-DDE and malathion, while boury fish of River Nile contained a higher level of zectran only. This survey, thus indicated that Manzala Lake and even the River Nile which was used as control are heavily contaminated with chlorinated hydrocarbons (Indian, heptachlor, aldrin, endrin, dieldrin, P,P'-DDE and DDT), organic phosphorus compounds (malathion, dimethoat, diazinon and parathion) and carbamate pesticides (propoxur and zectran).

  2. Is Solar Variability Reflected in the Nile River?

    NASA Technical Reports Server (NTRS)

    Ruzmaikin, Alexander; Feynman, Joan; Yung, Yuk L.

    2006-01-01

    We investigate the possibility that solar variability influences North African climate by using annual records of the water level of the Nile collected in 622-1470 A.D. The time series of these records are nonstationary, in that the amplitudes and frequencies of the quasi-periodic variations are time-dependent. We apply the Empirical Mode Decomposition technique especially designed to deal with such time series. We identify two characteristic timescales in the records that may be linked to solar variability: a period of about 88 years and one exceeding 200 years. We show that these timescales are present in the number of auroras reported per decade in the Northern Hemisphere at the same time. The 11-year cycle is seen in the Nile's high-water level variations, but it is damped in the low-water anomalies. We suggest a possible physical link between solar variability and the low-frequency variations of the Nile water level. This link involves the influence of solar variability on the atmospheric Northern Annual Mode and on its North Atlantic Ocean and Indian Ocean patterns that affect the rainfall over the sources of the Nile in eastern equatorial Africa.

  3. Is Solar Variability Reflected in the Nile River?

    NASA Technical Reports Server (NTRS)

    Ruzmaikin, Alexander; Feynman, Joan; Yung, Yuk L.

    2006-01-01

    We investigate the possibility that solar variability influences North African climate by using annual records of the water level of the Nile collected in 622-1470 A.D. The time series of these records are nonstationary, in that the amplitudes and frequencies of the quasi-periodic variations are time-dependent. We apply the Empirical Mode Decomposition technique especially designed to deal with such time series. We identify two characteristic timescales in the records that may be linked to solar variability: a period of about 88 years and one exceeding 200 years. We show that these timescales are present in the number of auroras reported per decade in the Northern Hemisphere at the same time. The 11-year cycle is seen in the Nile's high-water level variations, but it is damped in the low-water anomalies. We suggest a possible physical link between solar variability and the low-frequency variations of the Nile water level. This link involves the influence of solar variability on the atmospheric Northern Annual Mode and on its North Atlantic Ocean and Indian Ocean patterns that affect the rainfall over the sources of the Nile in eastern equatorial Africa.

  4. Permian and Triassic microfloral assemblages from the Blue Nile Basin, central Ethiopia

    NASA Astrophysics Data System (ADS)

    Dawit, Enkurie L.

    2014-11-01

    Palynological investigation was carried out on surface samples from up to 400 m thick continental siliciclastic sediments, here referred to as “Fincha Sandstone”, in the Blue Nile Basin, central Ethiopia. One hundred sixty species were identified from 15 productive samples collected along a continuous road-cut exposure. Six informal palynological assemblage zones have been identified. These assemblage zones, in ascending order, are: “Central Ethiopian Permian Assemblage Zone - CEPAZ I”, earliest Permian (Asselian-Sakmarian); “CEPAZ II”, late Early Permian (Artinskian-Kungurian); CEPAZ III - Late Permian (Kazanian-Tatarian); “CETAZ IV”, Lower Triassic (Olenekian Induan); “CETAZ V”, Middle Triassic (Anisian Ladinian); “CETAZ VI”, Late Triassic (Carnian Norian). Tentative age ranges proposed herein are compared with faunally calibrated palynological zones in Gondwana. The overall composition and vertical distribution of miospores throughout the studied section reveals a wide variation both qualitatively and quantitatively. The high frequency of monosaccate pollen in CEPAZ I may reflect a Glossopterid-dominated upland flora in the earliest Permian. The succeeding zone is dominated by straite/taeniate disaccate pollen and polyplicates, suggesting a notable increase in diversity of glossopterids. The decline in the diversity of taeniate disaccate pollen and the concomitant rise in abundance of non-taeniate disaccates in CEPAZ III may suggest the decline in Glossopteris diversity, though no additional evidence is available to equate this change with End-Permian extinction. More diverse and dominant non-taeniate, disaccate, seed fern pollen assignable to FalcisporitesAlisporites in CETAZ IV may represent an earliest Triassic recovery flora. The introduction of new disaccate forms with thick, rigid sacci, such as Staurosaccites and Cuneatisporites, in CETAZ V and VI may indicate the emergence of new gymnospermous plants that might have favourably

  5. Development of a Nile-blue based chemodosimeter for Hg2+ in aqueous solution and its application in biological imaging.

    PubMed

    Hu, Mingming; Yin, Jianhua; Li, Yahong; Zhao, Xiaofang

    2015-03-01

    A Nile blue-based chemodosimeter was newly synthesized. It can detect Hg(2+) in aqueous solution based on desulfurization reaction. Upon its addition into aqueous Hg(2+) ion solution, it exhibited a considerable blue-shift in its absorption and obvious fluorescence quenching. The detection mechanism was proved by mass spectrometry analysis and Gaussian calculations. Detection at an emission of 685 nm was extremely sensitive, with a detection limit of 2.5 × 10(-9) mol/L. The fluorescent images in living cells and zebrafish demonstrate its potential for studying the accumulation of mercury species in organism.

  6. Building Climate Resilience in the Blue Nile/Abay Highlands: A Role for Earth System Sciences

    PubMed Central

    Zaitchik, Benjamin F.; Simane, Belay; Habib, Shahid; Anderson, Martha C.; Ozdogan, Mutlu; Foltz, Jeremy D.

    2012-01-01

    The Blue Nile (Abay) Highlands of Ethiopia are characterized by significant interannual climate variability, complex topography and associated local climate contrasts, erosive rains and erodible soils, and intense land pressure due to an increasing population and an economy that is almost entirely dependent on smallholder, low-input agriculture. As a result, these highland zones are highly vulnerable to negative impacts of climate variability. As patterns of variability and precipitation intensity alter under anthropogenic climate change, there is concern that this vulnerability will increase, threatening economic development and food security in the region. In order to overcome these challenges and to enhance sustainable development in the context of climate change, it is necessary to establish climate resilient development strategies that are informed by best-available Earth System Science (ESS) information. This requirement is complicated by the fact that climate projections for the Abay Highlands contain significant and perhaps irreducible uncertainties. A critical challenge for ESS, then, is to generate and to communicate meaningful information for climate resilient development in the context of a highly uncertain climate forecast. Here we report on a framework for applying ESS to climate resilient development in the Abay Highlands, with a focus on the challenge of reducing land degradation. PMID:22470302

  7. Linking soil erosion to onsite financial cost: lessons from watersheds in the Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Erkossa, T.; Wudneh, A.; Desalegn, B.; Taye, G.

    2015-02-01

    The study was conducted in three watersheds (Dapo, Meja and Mizewa) in the Ethiopian part of the Blue Nile Basin to estimate the onsite cost of soil erosion using the productivity change approach, in which crop yield reduction due to plant nutrients lost with the sediment and runoff has been analyzed. For this purpose, runoff measurement and sampling was conducted during the main rainy season of 2011 at the outlet of two to three sub watersheds in each watershed. The sediment concentration of the runoff, and nitrogen and phosphorus content of the runoff and sediment were determined. Crop response functions were developed for the two plant nutrients based on data obtained from the nearest Agricultural Research Centers. The response functions were used to estimate crop yield reduction as a result of the lost N and P assuming there is no compensation through fertilization. The results show a significant yield reduction and resultant financial loss to the farmers. Considering only grain yield of maize (Zea mays), farmers at Dapo annually lose about 220 and USD 150 ha-1 due to the loss of nitrogen and phosphorus, respectively. In view of the importance of the crop residues including as feed, the loss can be even greater. The study demonstrated that in addition to the long-term deterioration of land quality, the annual financial loss suffered by farmers is substantial. Therefore, on farm soil and water conservation measures that are suitable in biophysical and socio-economic terms in the landscapes and beyond need to be encouraged.

  8. Heterogeneous photocatalytic degradation of nile blue dye in aqueous BiOCl suspensions

    NASA Astrophysics Data System (ADS)

    Sarwan, Bhawna; Pare, B.; Acharya, A. D.

    2014-05-01

    Bismuth oxychloride (BiOCl) was synthesized by hydrolysis method. Several analytical tools such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller (BET) surface area, X-ray photoelectron spectroscopic, and energy-dispersive spectroscopic techniques were used to characterize the sample. The prepared material had average pore diameter of about 7-10 nm and the BET surface area of BiOCl was 40 m2 g-1. The analysis of hydroxyl radicals (•OH) formation was performed by fluorescence technique. The intermediates and the final products of degradation were detected by high-performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry (HPLC-ESI-DAD-MS) technology. The degradation of nile blue (NB) dye was mainly attributed to the destruction of the conjugated structure, and after that the intermediates were transformed into small molecules mainly phenol, aniline, etc., which were mineralized to water and carbon dioxide. During three recycles, the catalyst did not exhibit any significant loss of photocatalytic activity, confirming that the photocatalyst is essentially stable. The NB oxidation was evaluated by the decrease in total organic carbon (TOC) content. The formation of NO3- and the evolution of CO2 revealed complete mineralization of aqueous NB during the photocatalytic process by this photocatalyst.

  9. Water resources planning under climate change: Assessing the robustness of real options for the Blue Nile

    NASA Astrophysics Data System (ADS)

    Jeuland, Marc; Whittington, Dale

    2014-03-01

    This article presents a methodology for planning new water resources infrastructure investments and operating strategies in a world of climate change uncertainty. It combines a real options (e.g., options to defer, expand, contract, abandon, switch use, or otherwise alter a capital investment) approach with principles drawn from robust decision-making (RDM). RDM comprises a class of methods that are used to identify investment strategies that perform relatively well, compared to the alternatives, across a wide range of plausible future scenarios. Our proposed framework relies on a simulation model that includes linkages between climate change and system hydrology, combined with sensitivity analyses that explore how economic outcomes of investments in new dams vary with forecasts of changing runoff and other uncertainties. To demonstrate the framework, we consider the case of new multipurpose dams along the Blue Nile in Ethiopia. We model flexibility in design and operating decisions—the selection, sizing, and sequencing of new dams, and reservoir operating rules. Results show that there is no single investment plan that performs best across a range of plausible future runoff conditions. The decision-analytic framework is then used to identify dam configurations that are both robust to poor outcomes and sufficiently flexible to capture high upside benefits if favorable future climate and hydrological conditions should arise. The approach could be extended to explore design and operating features of development and adaptation projects other than dams.

  10. Building climate resilience in the Blue Nile/Abay Highlands: a role for Earth system sciences.

    PubMed

    Zaitchik, Benjamin F; Simane, Belay; Habib, Shahid; Anderson, Martha C; Ozdogan, Mutlu; Foltz, Jeremy D

    2012-02-01

    The Blue Nile (Abay) Highlands of Ethiopia are characterized by significant interannual climate variability, complex topography and associated local climate contrasts, erosive rains and erodible soils, and intense land pressure due to an increasing population and an economy that is almost entirely dependent on smallholder, low-input agriculture. As a result, these highland zones are highly vulnerable to negative impacts of climate variability. As patterns of variability and precipitation intensity alter under anthropogenic climate change, there is concern that this vulnerability will increase, threatening economic development and food security in the region. In order to overcome these challenges and to enhance sustainable development in the context of climate change, it is necessary to establish climate resilient development strategies that are informed by best-available Earth System Science (ESS) information. This requirement is complicated by the fact that climate projections for the Abay Highlands contain significant and perhaps irreducible uncertainties. A critical challenge for ESS, then, is to generate and to communicate meaningful information for climate resilient development in the context of a highly uncertain climate forecast. Here we report on a framework for applying ESS to climate resilient development in the Abay Highlands, with a focus on the challenge of reducing land degradation.

  11. Nile blue shows its true colors in gas-phase absorption and luminescence ion spectroscopy

    NASA Astrophysics Data System (ADS)

    Stockett, M. H.; Houmøller, J.; Brøndsted Nielsen, S.

    2016-09-01

    Nile blue is used extensively in biology as a histological stain and fluorescent probe. Its absorption and emission spectra are strongly solvent dependent, with variations larger than 100 nm. The molecule is charged due to an iminium group, and it is therefore an obvious target for gas-phase ion spectroscopy. Here we report the absorption and emission spectra of the mass-selected bare ions isolated in vacuo, and based on our results we revisit the interpretation of solution-phase spectra. An accelerator mass spectrometer was used for absorption spectroscopy where the absorption is represented by the yield of photofragment ions versus excitation wavelength (action spectroscopy). The luminescence experiments were done with a newly built ion trap setup equipped with an electrospray ion source, and some details on the mass selection technique will be given which have not been described before. In vacuo, the absorption and emission maxima are at 580 ± 10 nm and 628 ± 1 nm. These values are somewhat blue-shifted relative to those obtained in most solvents; however, they are much further to the red than those in some of the most non-polar solvents. Furthermore, the Stokes shift in the gas phase (1300 cm-1) is much smaller than that in these non-polar solvents but similar to that in polar ones. An explanation based on charge localization by solvent dipoles, or by counterions in some non-polar solvents, can fully account for these findings. Hence in the case of ions, it is nontrivial to establish intrinsic electronic transition energies from solvatochromic shifts alone.

  12. SAR Interferometry as a Tool for Monitoring Coastal Changes in the Nile River Delta of Egypt

    NASA Technical Reports Server (NTRS)

    Aly, Mohamed H.; Klein, Andrew G.; Giardino, John R.

    2005-01-01

    The Nile River Delta is experiencing rapid rates of coastal change. The rate of both coastal retreat and accretion in the Eastern Nile Delta requires regular, accurate detection and measurement. Current techniques used to monitor coastal changes in the delta are point measurements and, thus, they provide a spatially limited view of the ongoing coastal changes. SAR interferometry can provide measurements of subtle coastal change at a significantly improved spatial resolution and over large areas (100 sq km). Using data provided by the ERS-1&2 satellites, monitoring can be accomplished as frequently as every 35 days when needed. Radar interferometry is employed in this study to detect segments of erosion and accretion during the 1993-2000 period. The average rates of erosion and accretion in the Eastern Nile Delta are measured to be -11.64 m/yr and +5.12 m/yr, respectively. The results of this interferometric study can be used effectively for coastal zone management and integrated sustainable development for the Nile River Delta.

  13. SAR Interferometry as a Tool for Monitoring Coastal Changes in the Nile River Delta of Egypt

    NASA Technical Reports Server (NTRS)

    Aly, Mohamed H.; Klein, Andrew G.; Giardino, John R.

    2005-01-01

    The Nile River Delta is experiencing rapid rates of coastal change. The rate of both coastal retreat and accretion in the Eastern Nile Delta requires regular, accurate detection and measurement. Current techniques used to monitor coastal changes in the delta are point measurements and, thus, they provide a spatially limited view of the ongoing coastal changes. SAR interferometry can provide measurements of subtle coastal change at a significantly improved spatial resolution and over large areas (100 sq km). Using data provided by the ERS-1&2 satellites, monitoring can be accomplished as frequently as every 35 days when needed. Radar interferometry is employed in this study to detect segments of erosion and accretion during the 1993-2000 period. The average rates of erosion and accretion in the Eastern Nile Delta are measured to be -11.64 m/yr and +5.12 m/yr, respectively. The results of this interferometric study can be used effectively for coastal zone management and integrated sustainable development for the Nile River Delta.

  14. STS-56 view of freeflying SPARTAN-201 and Earth observation of Nile River,Egypt

    NASA Technical Reports Server (NTRS)

    1993-01-01

    During STS-56, the Shuttle Pointed Autonomous Research Tool for Astronomy 201 (SPARTAN-201), a freeflying payload, is captured as it orbits the Earth above the Nile River Valley in Egypt. This synoptic view taken aboard Discovery, Orbiter Vehicle (OV) 103, reveals the landscapes of the Sinai and the Gulf of Suez on the left and the Qatara Depression on the right. The Nile River Valley and the base of the delta feature are in the center. The leaf-like appearance of El Fayum is clearly seen. The city of Cairo is also easily recognized at the base of the delta. SPARTAN-201 was later captured by OV-103's remote manipulator system (RMS) and returned to Earth with the astronaut crew.

  15. Effect of regulation of the Nile River on the bioproductivity of Southeastern Mediterranean Sea

    SciTech Connect

    Wadia, W.

    1982-01-01

    The Nile River previously brought a large quantity of dissolved nutrients and organic matter into the Southeastern Mediterranean Sea. Since completion of the Aswan hydrocomplex, reduction in the river flow has caused significant change in the distribution of the physico-chemical indices of the sea water as well as in the formation and distribution of the water masses in the region located north of the Nile delta. In recent years changes have been recorded in the dynamics and distribution of water temperature. From 1966 the sediment runoff of the Nile began dropping sharply due not only to reduction in the volume of river water reaching the sea, but also due to a significant reduction in the suspended particles in the flow. This has had a harmful effect on the formation and dynamics of grounds and banks near the delta and north of it. The reproduction of the shrimp in the area has changed significantly in timing and the food supplies for the young shrimp have deteriorated. Shrimp catches in 1966 were half what they had been in 1963. Commercial fishes have also decreased in numbers. Thus all links of the trophic chain have been affected from the phytoplankton to the pelagic and benthic fishes. 11 references, 3 tables.

  16. Two Myxobolus spp. infecting the kidney of Nile tilapia (Oreochromis niloticus) in the River Nile at Beni-Suef governorate, Egypt, and the associated renal changes.

    PubMed

    Abdel-Baki, Abdel-Azeem S; Abdel-Haleem, Heba M; Sakran, Thabet; Zayed, Eman; Ibrahim, Khalid E; Al-Quraishy, Saleh

    2015-03-01

    Two Myxobolus spp. are described from the kidney of the Nile tilapia (Oreochromis niloticus) collected from the River Nile, Egypt. The prevalence of infection was 61 % (47/77), with the infected fish in each case parasitized by the two Myxobolus species simultaneously. The infection was exhibited as free spores in Bowman capsules and renal glomeruli, which makes their original structures difficult to discern. In some cases, the infection appeared as a fibrous plasmodia-like structure containing degenerated developmental stages and spores in the interstitium. The paper identifies each species based on the morphological characteristics of its spores and identifies the histological impacts of Myxobolus infection in this species of fish.

  17. Assessing and managing water scarcity within the Nile River Transboundary Basin

    NASA Astrophysics Data System (ADS)

    Butts, M. B.; Wendi, D.; Jessen, O. Z.; Riegels, N. D.

    2012-04-01

    The Nile Basin is the main source of water in the North Eastern Region of Africa and is perhaps one of the most critical river basins in Africa as the riparian countries constitute 40% of the population on the continent but only 10% of the area. This resource is under considerable stress with rising levels of water scarcity, high population growth, watershed degradation, and loss of environmental services. The potential impacts of climate change may significantly exacerbate this situation as the water resources in the Nile Basin are critically sensitive to climate change (Conway, Hanson, Doherty, & Persechino, 2007). The motivation for this study is an assessment of climate change impacts and adaptation potential for floods and droughts within the UNEP project "Adapting to climate change induced water stress in the Nile River Basin", supported by SIDA. This project is being carried out as collaboration between DHI, the UK Met Office, and the Nile Basin Initiative (NBI). The Nile Basin exhibits highly diverse climatological and hydrological characteristics. Thus climate change impacts and adaptive capacity must be addressed at both regional and sub-basin scales. While the main focus of the project is the regional scale, sub-basin scale modelling is required to reflect variability within the basin. One of the major challenges in addressing this variability is the scarcity of data. This paper presents an initial screening modelling study of the water balance of the Nile Basin along with estimates of expected future impacts of climate change on the water balance. This initial study is focussed on the Ethiopian Highlands and the Lake Victoria regions, where the impact of climate change on rainfall is important. A robust sub-basin based monthly water balance model is developed and applied to selected sub-basins. The models were developed and calibrated using publicly available data. One of the major challenges in addressing this variability within the basin is the

  18. Anatomy of a river drainage reversal in the Neogene Kivu Nile Rift

    NASA Astrophysics Data System (ADS)

    Holzförster, F.; Schmidt, U.

    2007-07-01

    The Neogene geological history of East Africa is characterised by the doming and extension in the course of development of the East African Rift System with its eastern and western branches. In the centre of the Western Rift Rise Rwanda is situated on Proterozoic basement rocks exposed in the strongly uplifted eastern rift shoulder of the Kivu-Nile Rift segment, where clastic sedimentation is largely restricted to the rift axis itself. A small, volcanically and tectonically controlled depository in northwestern Rwanda preserved the only Neogene sediments known from the extremely uplifted rift shoulder. Those (?)Pliocene to Pleistocene/Holocene fluvio-lacustrine muds and sands of the Palaeo-Nyabarongo River record the influence of Virunga volcanism on the major drainage reversal that affected East Africa in the Plio-/Pleistocene, when the originally rift-parallel upper Nile drainage system became diverted to the East in order to enter the Nile system via Lake Victoria. Sedimentary facies development, heavy mineral distributions and palaeobiological controls, including hominid artefacts, signal a short time interval of <300-350 ka to complete this major event for the sediment supply system of the Kivu-Nile Rift segment.

  19. Building climate resilience in the Blue Nile/Abay Highlands: a framework for action.

    PubMed

    Simane, Belay; Zaitchik, Benjamin F; Mesfin, Desalegn

    2012-02-01

    Ethiopia has become warmer over the past century and human induced climate change will bring further warming over the next century at unprecedented rates. On the average, climate models show a tendency for higher mean annual rainfall and for wetter conditions, in particular during October, November and December, but there is much uncertainty about the future amount, distribution, timing and intensity of rainfall. Ethiopia's low level of economic development, combined with its heavy dependence on agriculture and high population growth rate make the country particularly susceptible to the adverse effects of climate change. Nearly 90% of Ethiopia's population lives in the Highlands, which include the critical Blue Nile (Abay) Highlands--a region that holds special importance due to its role in domestic agricultural production and international water resources. A five year study of climate vulnerability and adaptation strategies in communities of Choke Mountain, located in the center of the Abay Highlands, has informed a proposed framework for enhancing climate resilience in communities across the region. The framework is motivated by the critical need to enhance capacity to cope with climate change and, subsequently, to advance a carbon neutral and climate resilient economy in Ethiopia. The implicit hypothesis in applying a research framework for this effort is that science-based information, generated through improved understanding of impacts and vulnerabilities of local communities, can contribute to enhanced resilience strategies. We view adaptation to climate change in a wider context of changes, including, among others, market conditions, the political-institutional framework, and population dynamics. From a livelihood perspective, culture, historical settings, the diversity of income generation strategies, knowledge, and education are important factors that contribute to adaptive capacities. This paper reviews key findings of the Choke Mountain study, describes

  20. Building Climate Resilience in the Blue Nile/Abay Highlands: A Framework for Action

    PubMed Central

    Simane, Belay; Zaitchik, Benjamin F.; Mesfin, Desalegn

    2012-01-01

    Ethiopia has become warmer over the past century and human induced climate change will bring further warming over the next century at unprecedented rates. On the average, climate models show a tendency for higher mean annual rainfall and for wetter conditions, in particular during October, November and December, but there is much uncertainty about the future amount, distribution, timing and intensity of rainfall. Ethiopia’s low level of economic development, combined with its heavy dependence on agriculture and high population growth rate make the country particularly susceptible to the adverse effects of climate change. Nearly 90% of Ethiopia’s population lives in the Highlands, which include the critical Blue Nile (Abay) Highlands—a region that holds special importance due to its role in domestic agricultural production and international water resources. A five year study of climate vulnerability and adaptation strategies in communities of Choke Mountain, located in the center of the Abay Highlands, has informed a proposed framework for enhancing climate resilience in communities across the region. The framework is motivated by the critical need to enhance capacity to cope with climate change and, subsequently, to advance a carbon neutral and climate resilient economy in Ethiopia. The implicit hypothesis in applying a research framework for this effort is that science-based information, generated through improved understanding of impacts and vulnerabilities of local communities, can contribute to enhanced resilience strategies. We view adaptation to climate change in a wider context of changes, including, among others, market conditions, the political-institutional framework, and population dynamics. From a livelihood perspective, culture, historical settings, the diversity of income generation strategies, knowledge, and education are important factors that contribute to adaptive capacities. This paper reviews key findings of the Choke Mountain study

  1. Impact of rehabilitation of Assiut barrage, Nile River, on groundwater rise in urban areas

    NASA Astrophysics Data System (ADS)

    Dawoud, Mohamed A.; El Arabi, Nahed E.; Khater, Ahmed R.; van Wonderen, Jan

    2006-08-01

    To make optimum use of the most vital natural resource of Egypt, the River Nile water, a number of regulating structures (in the form of dams and barrages) for control and diversion of the river flow have been constructed in this river since the start of the 20th century. One of these barrages is the Assiut barrage which will require considerable repairs in the near future. The design of the rehabilitation of the barrage includes a headpond with water levels maintained at a level approximately 0.60 m higher than the highest water level in the headpond of the present barrage. This development will cause an increase of the seepage flow from the river towards the adjacent agricultural lands, Assiut Town and villages. The increased head pond level might cause a rise of the groundwater levels and impedance of drainage outflows. The drainage conditions may therefore be adversely affected in the so-called impacted areas which comprise floodplains on both sides of the Nile for about 70 km upstream of the future barrage. A rise in the groundwater table, particularly when high river levels impede drainage, may result in waterlogging and secondary salinization of the soil profile in agricultural areas and increase of groundwater into cellars beneath buildings in the urban areas. In addition, a rise in the groundwater table could have negative impact on existing sanitation facilities, in particular in the areas which are served with septic tanks. The impacts of increasing the headpond level were assessed using a three-dimensional groundwater model. The mechanisms of interactions between the Nile River and the underlying Quaternary aquifer system as they affect the recharge/discharge processes are comprehensively outlined. The model has been calibrated for steady state and transient conditions against historical data from observation wells. The mitigation measures for the groundwater rise in the urban areas have been tested using the calibrated mode.

  2. Another unique river: a consideration of some of the characteristics of the trunk tributaries of the Nile River in northwestern Ethiopia in relationship to their aquatic food resources.

    PubMed

    Kappelman, John; Tewabe, Dereje; Todd, Lawrence; Feseha, Mulugeta; Kay, Marvin; Kocurek, Gary; Nachman, Brett; Tabor, Neil; Yadeta, Meklit

    2014-12-01

    Aquatic food resources are important components of many modern human hunter-gatherer diets and yet evidence attesting to the widespread exploitation of this food type appears rather late in the archaeological record. While there are times when, for example, the capture of fish and shellfish requires sophisticated technology, there are other cases when the exact ecological attributes of an individual species and the particulars of its environment make it possible for these foods to be incorporated into the human diet with little or no tool use and only a minimal time investment. In order to better understand the full set of variables that are considered in these sorts of foraging decisions, it is necessary to detail the attributes of each particular aquatic environment. We discuss here some of the characteristics of the trunk tributaries of the Nile and Blue Rivers in the Horn of Africa. Unlike typical perennial rivers, these 'temporary' rivers flow only during a brief but intense wet season; during the much longer dry season, the rivers are reduced to a series of increasingly disconnected waterholes, and the abundant and diverse fish and mollusk populations are trapped in ever smaller evaporating pools. The local human population today utilizes a number of diverse capture methods that range from simple to complex, and vary according to the size and depth of the waterhole and the time of the year. When we view the particular characteristics of an individual river system, we find that each river is 'unique' in its individual attributes. The Horn of Africa is believed to be along the route that modern humans followed on their migration out of Africa, and it is likely that the riverine-based foraging behaviors of these populations accompanied our species on its movement into the rest of the Old World. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Seasonal fluctuation and histopathology of Henneguya ghaffari (Myxozoa: Myxosporea) infection in the gills of the Nile perch, Lates niloticus, in the River Nile: a new locality record.

    PubMed

    Abdel-Baki, Abdel-Azeem S; Sakran, Thabet; Zayed, Eman; Al-Quraishy, Saleh

    2014-04-01

    Henneguya ghaffari Ali (Dis Aquat Org 38:225-230, 1999), which was originally described in Lake Wadi El-Rayan in the western desert of Egypt, has been discovered in the gills of the Nile perch, Lates niloticus, sourced from the River Nile at Beni-Suef governorate. The species identification was based on the spore morphometry. Of 180 Nile perch, 68 were found to be naturally infected with H. ghaffari (37.7%). A significant seasonal fluctuation in the prevalence was discerned, with the maximum rate occurring in the winter (68.8%) and the minimum rate in the summer (8.8%). The plasmodia of the parasite were evident as white rods, occupying almost a third of the gill filament and with mean dimensions of 0.7 × 0.2 mm. Histological investigations revealed that the present plasmodia were potentially compatible with the intrafilamental type. Infection with H. ghaffari initiated epithelial hyperplasia and curling and atrophy of the respiratory lamellae, which underpin its deleterious effect on the host by decreasing the functional respiratory surface of the gills. The present study concluded that infection with H. ghaffari originated in the River Nile before moving to the new ecosystem of Lake Wadi El-Rayan through drainage water.

  4. Geochemistry of sediments and surface soils from the Nile Delta and lower Nile valley studied by epithermal neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Arafa, Wafaa M.; Badawy, Wael M.; Fahmi, Naglaa M.; Ali, Khaled; Gad, Mohamed S.; Duliu, Octavian G.; Frontasyeva, Marina V.; Steinnes, Eiliv

    2015-07-01

    The distributions of 36 major and trace elements in 40 surface soil and sediment samples collected from the Egyptian section of the river Nile were determined by epithermal neutron activation analysis and compared with corresponding data for the Upper Continental Crust and North American Shale Composite. Their relative distributions indicate the presence of detrital material of igneous origin, most probably resulting from weathering on Ethiopian highlands and transported by the Blue Nile, the Nile main tributary. The distributions of the nickel, zinc, and arsenic contents suggest that the lower part of the Nile and its surroundings including the Nile Delta is not seriously polluted with metals from local human activity. The geographical distributions of Na, Cl, and I as well as results of principal component analysis suggest atmospheric supply of these elements from the ocean. In general the present data may contribute to a better understanding of the geochemistry of the Nile sediments.

  5. Nile Blue-based nanosized pH sensors for simultaneous far-red and near-infrared live bioimaging.

    PubMed

    Madsen, Jeppe; Canton, Irene; Warren, Nicholas J; Themistou, Efrosyni; Blanazs, Adam; Ustbas, Burcin; Tian, Xiaohe; Pearson, Russell; Battaglia, Giuseppe; Lewis, Andrew L; Armes, Steven P

    2013-10-02

    Diblock copolymer vesicles are tagged with pH-responsive Nile Blue-based labels and used as a new type of pH-responsive colorimetric/fluorescent biosensor for far-red and near-infrared imaging of live cells. The diblock copolymer vesicles described herein are based on poly(2-(methacryloyloxy)ethyl phosphorylcholine-block-2-(diisopropylamino)ethyl methacrylate) [PMPC-PDPA]: the biomimetic PMPC block is known to facilitate rapid cell uptake for a wide range of cell lines, while the PDPA block constitutes the pH-responsive component that enables facile vesicle self-assembly in aqueous solution. These biocompatible vesicles can be utilized to detect interstitial hypoxic/acidic regions in a tumor model via a pH-dependent colorimetric shift. In addition, they are also useful for selective intracellular staining of lysosomes and early endosomes via subtle changes in fluorescence emission. Such nanoparticles combine efficient cellular uptake with a pH-responsive Nile Blue dye label to produce a highly versatile dual capability probe. This is in marked contrast to small molecule dyes, which are usually poorly uptaken by cells, frequently exhibit cytotoxicity, and are characterized by intracellular distributions invariably dictated by their hydrophilic/hydrophobic balance.

  6. Nile Blue-Based Nanosized pH Sensors for Simultaneous Far-Red and Near-Infrared Live Bioimaging

    PubMed Central

    2013-01-01

    Diblock copolymer vesicles are tagged with pH-responsive Nile Blue-based labels and used as a new type of pH-responsive colorimetric/fluorescent biosensor for far-red and near-infrared imaging of live cells. The diblock copolymer vesicles described herein are based on poly(2-(methacryloyloxy)ethyl phosphorylcholine-block-2-(diisopropylamino)ethyl methacrylate) [PMPC-PDPA]: the biomimetic PMPC block is known to facilitate rapid cell uptake for a wide range of cell lines, while the PDPA block constitutes the pH-responsive component that enables facile vesicle self-assembly in aqueous solution. These biocompatible vesicles can be utilized to detect interstitial hypoxic/acidic regions in a tumor model via a pH-dependent colorimetric shift. In addition, they are also useful for selective intracellular staining of lysosomes and early endosomes via subtle changes in fluorescence emission. Such nanoparticles combine efficient cellular uptake with a pH-responsive Nile Blue dye label to produce a highly versatile dual capability probe. This is in marked contrast to small molecule dyes, which are usually poorly uptaken by cells, frequently exhibit cytotoxicity, and are characterized by intracellular distributions invariably dictated by their hydrophilic/hydrophobic balance. PMID:24001153

  7. Hydro-environmental status and soil management of the River Nile Delta, Egypt

    NASA Astrophysics Data System (ADS)

    Elewa, H. H.; El Nahry, A. H.

    2009-04-01

    The sea level rise has its own-bearing on the coastal recession and hydro-environmental degradation of the River Nile Delta. Attempts are made here to use remote sensing to detect the coastal recession in some selected parts and delineating the chemistry of groundwater aquifers and surface water, which lie along south-mid-northern and coastal zone of the Nile Delta. Eight water samples from groundwater monitoring wells and 13 water samples from surface water were collected and analyzed for various hydrochemical parameters. The groundwater samples are classified into five hydrochemical facies on Hill-Piper trilinear diagram based on the dominance of different cations and anions: facies 1: Ca-Mg-Na-HCO3-Cl-SO4 type I; facies 2: Na-Cl-HCO3 type II; facies 3: Na-Ca-Mg-Cl type III, facies 4: Ca-Na-Mg-Cl-HCO3 type IV and facies 5: Na-Mg-Cl type V. The hydrochemical facies showed that the majority of samples were enriched in sodium, bicarbonate and chloride types and, which reflected that the sea water and tidal channel play a major role in controlling the groundwater chemical composition in the Quaternary shallow aquifers, with a severe degradation going north of Nile Delta. Also, the relationship between the dissolved chloride (Cl, mmol/l), as a variable, and other major ion combinations (in mmol/l) were considered as another criterion for chemical classification system. The low and medium chloride groundwater occurs in southern and mid Nile Delta (Classes A and B), whereas the high and very high chloride (classes D and C) almost covers the northern parts of the Nile Delta indicating the severe effect of sea water intrusion. Other facets of hydro-environmental degradation are reflected through monitoring the soil degradation process within the last two decades in the northern part of Nile Delta. Land degradation was assessed by adopting new approach through the integration of GLASOD/FAO approach and Remote Sensing/GIS techniques. The main types of human induced soil

  8. Trace metal levels in water, fish, and sediment from River Nile, Egypt: potential health risks assessment.

    PubMed

    Dahshan, Hesham; Abd-Elall, Amr Mohamed Mohamed; Megahed, Ayman Mohamed

    2013-01-01

    The purposes of this study were to describe the impact of metal pollution on the main economic fish species Tilapia nilotica and to assess the potential health risk from consuming this contaminated fish in Egypt. Trace metals, including Ag, Al, Cd, Bo, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, St, V, Zn, and As, were determined in water, Tilapia nilotica, and sediments from the River Nile, Domiate branch, Egypt. Metal concentrations in fish of Al, Cd, Co, Fe, Mn, Pb, V, and Zn (mg/kg dry weight [dw]) and concentrations in sediment of Cd, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn (mg/kg dw) were above the International Atomic Energy Agency (IAEA-407) levels. However, trace metals in river water were still at permissible levels for Egyptian standards. The hazard index (HI) of estimated metal mixtures for intake of Tilapia nilotica (23.37) demonstrated that intake resulted in higher noncarcinogenic risk. In conclusion, the overall problem of metal contamination in fish collected from the River Nile was more serious than postulated to occur in an industrialized and densely populated area. In the light of known risks to public health, environmental protection laws are needed in Egypt.

  9. A Comparative Study Environmental and Radiological Causes Of Cancer In River Nile State, Sudan

    NASA Astrophysics Data System (ADS)

    Hamid, Eyad; Khair, Hatim

    The causes of cancer in River Nile state are differ between environmental and radiological, this paper tried to make comparison between the two causes, to determine the real cause behind the large rising of cancer cases in this state, considering the daily habits for the patients and the possible contamination in the natural resources around them. The noticeable thing that most of cancer cases are might be due to the high concentration of nitrate pollutant detected in natural resources such as drinking water; also by looking to the radioactive elements we see there's high concentration of some radioactive elements specially the K-40 which found in Portulaca Oleracea.

  10. Screening of multiple hormonal activities in water and sediment from the river Nile, Egypt, using in vitro bioassay and gonadal histology.

    PubMed

    Osman, Alaa G M; AbouelFadl, Khaled Y; Krüger, Angela; Kloas, Werner

    2015-06-01

    In Egypt, until yet no records are available regarding possible multiple hormonal activities in the aquatic systems and especially in the river Nile. In this paper, in vitro yeast estrogen screen (YES) and yeast androgen screen (YAS) were used to assess (for the first time) the multiple hormonal activities in surface waters and sediments of the river Nile. This study aimed to determine whether river Nile water can cause changes in gonadal histology of Nile tilapia (Oreochromis niloticus niloticus). All water samples exhibited extremely low levels of estrogenicity. Estrogenicity was nearly not detected in any of the sediment samples. Unlike the estrogenicity, significant androgenic activities were recorded in the water and sediment samples along the course of the river Nile. The present study reports for the first time quantification anti-estrogenic and anti-androgenic activities with high levels in both water and sediment of the river Nile. The greatest anti-estrogenic and anti-androgenic activities were observed in samples from downstream river Nile. These results indicated that the anti-estrogenic and anti-androgenic activities along the Nile course were great and the pollution of the sites at downstream was more serious than the upstream sites due to industrial and anthropogenic activities at these sites. Good correlations were observed among some hormonal activities, suggesting coexistence of these contaminants in the environmental matrices. There were no signs of sexual disruption in any of the gonads analyzed from either male or female Nile tilapia, demonstrating that no hormonal activity present along the Nile course was sufficient to induce adverse effects on reproductive development. Further investigation is necessary to identify the compounds responsible for the hormonal activities in the river Nile and to examine effects of very low levels of hormonally active compounds on gonadal histology, as well as in the development of more sensitive biomarkers.

  11. Thelohanellus niloticus sp. nov. (Myxozoa: Myxosporea), a parasite of the Nile carp Labeo niloticus from the River Nile, Egypt.

    PubMed

    Abdel-Ghaffar, Fathy; Morsy, Kareem; Bashtar, Abdel-Rahman; El-Ganainy, Sahar; Gamal, Shams

    2013-01-01

    In the present study, the morphology and morphometric characterization of Thelohanellus niloticus sp. nov., a new myxozoan belonging to genus Thelohanellus Kudo, 1933 (Myxosporea, Bivalvulida) infecting the gills of Labeo niloticus (Osteichthyes, Cyprinidae), were described for the first time from the River Nile at El-Minia Governorate, Egypt. Forty-one out of 78 (52.6 %) of the examined fish were infected. The infection was observed as irregular, milky whitish, cyst-like plasmodia (up to 0.8 mm in diameter) attached to the gill filaments of the host fish. These plasmodia contained tear-shaped myxospores with slightly tapering anterior and rounded posterior ends. Each spore has a single pyriform polar capsule. Spores measured about 23.3 ± 0.3 (20.4-27.1) μm long and 13.4 ± 0.4 (11.5-14.2) μm wide. The polar capsule was 11.7 ± 0.3 (9.2-12.5) μm long and 4.7 ± 0.3 (3.5-6.2) μm wide, containing a polar filament coiled perpendicular to the longitudinal axis of the spore body making eight turns. Occasionally, an oblong, irregular-shaped mass of protoplasm with a slightly oval nucleus (1.4 μm in diameter) and a small iodinophilous vacuole measured 0.85 ± 0.2 μm (0.73-1.2 μm) were observed in the spore. Due to the lack of the second polar capsule characterizing Myxobolus sp., the present parasite is placed within the genus Thelohanellus. Based on morphological differences (compared with other members of Thelohanellus Kudo, 1933) and the host specificity, this species is described as a new one of the genus Thelohanellus recorded for the first time in Egypt.

  12. Assessment of Active Landslides in Sanbaro Sago Valley, Blue-Nile Catchment, Ethiopia

    NASA Astrophysics Data System (ADS)

    Hailemariam Gugsa, Trufat

    2010-05-01

    In fall of 2009, a detail field mapping was carried out in the Sanbaro Sago Valley, south-eastern of Blue-Nile catchment, to inspect the landslide processes that affected the livelihood of more than 6,000 peoples. The valley is a part of Ethiopian highlands where long histories of rainfall triggered landslides are prominent. The villagers suffered the recurring landslides for the last five years, even at present; there are numerous evidences of active landslides, with some actual slides currently taking place. The nature their activity indicate high probability of destructive phenomena within the foreseeable future. The landslides already damaged houses, farm plots and drainage ditch, as well; more than 40 causalities are recorded. Most of the dwellers have been permanently displaced from their residences, as they lost their houses and farm plots. A preliminary zoning was made through the interpretation of satellite images (+ETM Land sat) that drape over the digital elevation model of the area, which followed by detail field investigation to map the geological, geomorphological, and anthropogenic factors that contribute to the landslide activity. The valley consists of low lying graben bounded by steep scarps that characterized by highly weathered Tertiary basaltic rocks covered with Quaternary deposits. Structurally controlled, alluvial and denudational landforms are present. There are distinct geomorphic units formed by differences in the lithology of the various basalt types. The Quaternary deposits along the ridge that has many rills and incised gullies are characterized by weathered basalts and alluvial-colluvial deposits. The elevation of the valley ranges from 1290m to 3200m m.a.s.l. The steep slopes, volcanic hills, exposed on the downthrown side of the major scarps have been modified by erosion, resulting in a highly dissected topography with steep gullies. This makes the steep slopes of the ridge to be one of landslide prone areas. Many of the active

  13. Ecological Risk Assessment of Metal Pollution along Greater Cairo Sector of the River Nile, Egypt, Using Nile Tilapia, Oreochromis niloticus, as Bioindicator

    PubMed Central

    Omar, Wael A.; Mikhail, Wafai Z. A.; Abdo, Hanaa M.; Abou El Defan, Tarek A.; Poraas, Mamdouh M.

    2015-01-01

    The present work aims to evaluate seasonal metal pollution along Greater Cairo sector of the River Nile, Egypt, using wild Nile tilapia, Oreochromis niloticus, as bioindicator and to conduct a risk assessment for human consumers. Greater Cairo is the largest populated area along the whole course of River Nile with a wide range of anthropogenic activities. Effects of metal pollution on fish body indices were studied using condition factor (CF) and scaled mass index (SMI). Metal pollution index (MPI) showed that the total metal load in fish organs followed the follwoing order: kidney > liver > gill > muscle which gives a better idea about the target organs for metal accumulation. Metal concentrations in fish muscle (edible tissue) showed the following arrangement: Fe > Zn > Cu > Mn > Pb > Cd. Metal's bioaccumulation factor (BAF) in fish muscle showed the following arrangement: Zn > Cu > Fe > Mn > Cd and Pb. The hazard index (HI) as an indicator of human health risks associated with fish consumption showed that adverse health effects are not expected to occur in most cases. However, the metals' cumulative risk effects gave an alarming sign specifically at high fish consumption rates. PMID:26617637

  14. Palaeo-geomorphology of The Nile River in Upper Egypt by using geomorphological and geoarchaeological indicators

    NASA Astrophysics Data System (ADS)

    Magdy, Torab

    2017-04-01

    Ancient Egyptians built their temples purposefully close to the River Nile in order to use it for transporting construction stones from faraway quarries to building sites in river-boats. Most temples, therefore, have river-horbours associated with their geometric designs. The paleo-river channel can be remapped based on this idea, beside other geomorphological and geoarchaeological indicators / evidence located between Aswan and Luxor cites. In this sense, this paper will define the characteristics of this ancient course and its associated landforms using paleochannel morphology, paleo-meandering and ancient river dynamics during historic and prehistoric times. It will adopt a geo-archaeological approach including field surveying and mapping, manual auger drilling, grain-size distribution of sample sediments and dating. In addition, multi-date satellite-image interpretations and historic topographic maps will also be used to reconstruct the paleo-geomorphological map of the river course and to investigate its ancient morphology south of Luxor, starting with observations from the present to prehistoric times.

  15. Assessing the Effects of Climate Change on Drought Risk for the Nile River Basin

    NASA Astrophysics Data System (ADS)

    Strzepek, K. M.; Boehlert, B. B.; Vogel, R. M.

    2012-12-01

    Approximately 90 percent of the Nile River runoff is generated within two regions—the Ethiopian highlands and the Lake Victoria and Equatorial Lakes—that have historically contrasting precipitation regimes. As a result of uncorrelated interannual rainfall variability, meteorological droughts in one region are typically offset by wetter periods in the other, thus having a moderating effect on downstream Nile river flow to Sudan and Egypt. Under climate change, the drivers of these contrasting rainfall regimes (including the annual migration of the Inter Tropical Convergence Zone) may be fundamentally altered such that droughts become correlated between these regions, leading to unprecedented low flows in the downstream Nile. The water management challenges that would result are likely to be exacerbated if climate change increases drought occurrence and intensity across the basin. In this research, we first assess the effect of climate change on drought frequency and intensity across eight Nile subbasins by applying the Standardized Precipitation Index (SPI) and the Palmer Drought Severity Index (PDSI) to the full suite of 22 Intergovernmental Panel on Climate Change General Circulation Models for three IPCC-SRES emissions scenarios (B1, A1B, and A2 from the Special Report on Emissions Scenarios (SRES)). We then use these outputs to evaluate how climate change affects the correlation of drought occurrence and intensity between the Ethiopian highlands and the Lake Victoria and Equatorial Lakes regions. In the first inquiry, we find that the frequency of drought over the next century based on precipitation alone (SPI) is projected to increase in the northern Nile basin, and decrease in the southern regions. Drought frequencies based on both precipitation and temperature (PDSI) are projected to increase across most of the Nile basin, however, with almost universally experienced increases in drought risk by the late 21st century. For both measures, the Ethiopia

  16. Designing multi-reservoir system designs via efficient water-energy-food nexus trade-offs - Selecting new hydropower dams for the Blue Nile and Nepal's Koshi Basin

    NASA Astrophysics Data System (ADS)

    Harou, J. J.; Hurford, A.; Geressu, R. T.

    2015-12-01

    Many of the world's multi-reservoir water resource systems are being considered for further development of hydropower and irrigation aiming to meet economic, political and ecological goals. Complex river basins serve many needs so how should the different proposed groupings of reservoirs and their operations be evaluated? How should uncertainty about future supply and demand conditions be factored in? What reservoir designs can meet multiple goals and perform robustly in a context of global change? We propose an optimized multi-criteria screening approach to identify best performing designs, i.e., the selection, size and operating rules of new reservoirs within multi-reservoir systems in a context of deeply uncertain change. Reservoir release operating rules and storage sizes are optimized concurrently for each separate infrastructure design under consideration across many scenarios representing plausible future conditions. Outputs reveal system trade-offs using multi-dimensional scatter plots where each point represents an approximately Pareto-optimal design. The method is applied to proposed Blue Nile River reservoirs in Ethiopia, where trade-offs between capital costs, total and firm energy output, aggregate storage and downstream irrigation and energy provision for the best performing designs are evaluated. The impact of filling period for large reservoirs is considered in a context of hydrological uncertainty. The approach is also applied to the Koshi basin in Nepal where combinations of hydropower storage and run-of-river dams are being considered for investment. We show searching for investment portfolios that meet multiple objectives provides stakeholders with a rich view on the trade-offs inherent in the nexus and how different investment bundles perform differently under plausible futures. Both case-studies show how the proposed approach helps explore and understand the implications of investing in new dams in a global change context.

  17. Nile River discharge and Eastern Mediterranean Sea surface freshening during sapropel S1 formation

    NASA Astrophysics Data System (ADS)

    Menke, Valerie; Weldeab, Syee; Schmiedl, Gerhard

    2016-04-01

    Cyclically reoccurring sapropels, layers of organic rich deposits, found in the Eastern Mediterranean sediment record during the Holocene to Pliocene are manifestations of extreme oceanographic events. However, the driving forces that lead to severely reduced deep- water ventilation and the collapse of benthic ecosystems have not been sufficiently identified. The cease in circulation has long been considered a response to major surface water freshening episodes caused by enhanced riverine input from the surrounding continents, with the main source being the Nile River, the Black Sea outflow or a combination thereof. Here we generate a dataset of trace element and stable isotope measurements that record runoff and sea surface temperature (SST) and focus on the most recent Eastern Mediterranean Sea (EMS) sapropel to determine the main freshwater sources driving sapropel formation. Based on the sequence of events, we rule out a role of Black Sea outflow in triggering and sustaining the EMS Holocene surface freshening. Our results indicate that the timing and duration of the extreme events reflect a combined effect of significantly enhanced Nile River runoff and EMS surface warming during winter. We suggest that the coincidence of these factors arose due to concomitant strengthening of the East African summer monsoon and most likely persistently negative mode of the North Atlantic Oscillation, a meteorological phenomenon that has a strong impact on Eastern Mediterranean winter hydroclimate.

  18. Relationship between heavy metals in mud sediments and beach soil of the River Nile

    SciTech Connect

    Awadallah, R.M.; Soltan, M.E.; Rashed, M.N.

    1996-08-01

    the chemical partitioning of selected inorganic ions was investigated in mud sediments taken from the bottom of the main stream of the River Nile by means of sediment sampler and beach soil samples collected from seven sectors (three subsamples from each location) between Aswan and Giza (Aswan, Qena, Sohag, Assiut, El Menya, Beni Suef, and Giza). These samples were analyzed by an atomic absorption spectrophotometer. The results showed that iron and lead were found at higher levels in beach soil than in the river sediments at all sites except for iron sediments of Aswan where the region was subjected to volcanic activities in the ancient geological eras (granites,.....etc.). At some sites, some heavy-metal concentrations seemed to be higher in sediment than in beach soil as a result of weathering of beach soil by the effect of wind and currents of water. In other sites, sediment pollution by these metals might be attributed to inputs from industrial effluents and domestic wastewater drained directly into the Nile. Statistical analysis of data shows significant correlation coefficient values (r= up to 0.915) 30 refs., 1 fig., 2 tabs.

  19. An elusive search for regional flood frequency estimates in the River Nile basin

    NASA Astrophysics Data System (ADS)

    Nyeko-Ogiramoi, P.; Willems, P.; Mutua, F. M.; Moges, S. A.

    2012-03-01

    Estimation of peak flow quantiles in ungauged catchments is a challenge often faced by water professionals in many parts of the world. Approaches to address such problem exist but widely used technique such as flood frequency regionalization is often not subjected to performance evaluation. In this study we used the jack-knifing principle to assess the performance of the flood frequency regionalization in the complex and data scarce River Nile basin by examining the error (regionalization error) between locally and regionally estimated peak flow quantiles for different return periods (QT). Agglomerative hierarchical clustering based algorithms were used to search for regions with similar hydrological characteristics taking into account the huge catchment area and strong climatic differences across the area. Hydrological data sets employed were from 180 gauged catchments and several physical characteristics in order to regionalize 365 identified catchments. The GEV distribution, selected using L-moment based approach, was used to construct regional growth curves from which peak flow growth factors (QT/MAF) could be derived and mapped through interpolation. Inside each region, variations in at-site flood frequency distribution were modeled by regression of the mean annual maximum peak flow (MAF) versus catchment area. The results show that the performance of the regionalization is heavily dependent on the historical flow record length and the similarity of the hydrological characteristics inside the regions. The flood frequency regionalization of the River Nile basin can be improved if sufficient flow data of longer record length × 40 become available.

  20. An elusive search for regional flood frequency estimates in the River Nile basin

    NASA Astrophysics Data System (ADS)

    Nyeko-Ogiramoi, P.; Willems, P.; Mutua, F. M.; Moges, S. A.

    2012-09-01

    Estimation of peak flow quantiles in ungauged catchments is a challenge often faced by water professionals in many parts of the world. Approaches to address such problem exist, but widely used techniques such as flood frequency regionalisation is often not subjected to performance evaluation. In this study, the jack-knifing principle is used to assess the performance of the flood frequency regionalisation in the complex and data-scarce River Nile basin by examining the error (regionalisation error) between locally and regionally estimated peak flow quantiles for different return periods (QT). Agglomerative hierarchical clustering based algorithms were used to search for regions with similar hydrological characteristics. Hydrological data employed were from 180 gauged catchments and several physical characteristics in order to regionalise 365 identified catchments. The Generalised Extreme Value (GEV) distribution, selected using L-moment based approach, was used to construct regional growth curves from which peak flow growth factors could be derived and mapped through interpolation. Inside each region, variations in at-site flood frequency distribution were modelled by regression of the mean annual maximum peak flow (MAF) versus catchment area. The results showed that the performance of the regionalisation is heavily dependent on the historical flow record length and the similarity of the hydrological characteristics inside the regions. The flood frequency regionalisation of the River Nile basin can be improved if sufficient flow data of longer record length of at least 40 yr become available.

  1. STS-57 Earth observation of the Eastern Mediterranean, Nile River, Asia Minor

    NASA Technical Reports Server (NTRS)

    1993-01-01

    STS-57 Earth observation of the Eastern Mediterranean. From a high vantage point over the Nile River, this north-looking view shows the eastern Mediterranean and the entire landmass of Asia Minor, with the Black Sea dimly visible at the horizon. Many of the Greek islands can be seen in the Aegean Sea (top left), off the coast of Asia Minor. Cyprus is visible under atmospheric dust in the northeastern corner of the Mediterranean. The dust cloud covers the east end of the Mediterranean, its western edge demarcated by a line that cuts the center of the Nile Delta. This dust cloud originated far to the west, in Algeria, and moved northeast. A gyre of clouds in the southeast corner of the Mediterranean indicates a complementary counterclockwise (cyclonic) circulation of air. The Euphrates River appears as a thin green line (upper right) in the yellow Syrian desert just south of the mountains of Turkey. The Dead Sea (lower right) lies in a rift valley which extends north into Turkey and sout

  2. Testing for homogeneity of variance in time series: Long memory, wavelets, and the Nile River

    NASA Astrophysics Data System (ADS)

    Whitcher, B.; Byers, S. D.; Guttorp, P.; Percival, D. B.

    2002-05-01

    We consider the problem of testing for homogeneity of variance in a time series with long memory structure. We demonstrate that a test whose null hypothesis is designed to be white noise can, in fact, be applied, on a scale by scale basis, to the discrete wavelet transform of long memory processes. In particular, we show that evaluating a normalized cumulative sum of squares test statistic using critical levels for the null hypothesis of white noise yields approximately the same null hypothesis rejection rates when applied to the discrete wavelet transform of samples from a fractionally differenced process. The point at which the test statistic, using a nondecimated version of the discrete wavelet transform, achieves its maximum value can be used to estimate the time of the unknown variance change. We apply our proposed test statistic on five time series derived from the historical record of Nile River yearly minimum water levels covering 622-1922 A.D., each series exhibiting various degrees of serial correlation including long memory. In the longest subseries, spanning 622-1284 A.D., the test confirms an inhomogeneity of variance at short time scales and identifies the change point around 720 A.D., which coincides closely with the construction of a new device around 715 A.D. for measuring the Nile River. The test also detects a change in variance for a record of only 36 years.

  3. Comparison of Prognostic and Diagnostic Approaches to Modeling Evapotranspiration in the Nile River Basin

    NASA Astrophysics Data System (ADS)

    Yilmaz, M.; Anderson, M. C.; Zaitchik, B. F.; Crow, W. T.; Hain, C.; Ozdogan, M.; Chun, J. A.

    2012-12-01

    Actual evapotranspiration (ET) can be estimated using both prognostic and diagnostic modeling approaches, providing independent yet complementary information for hydrologic applications. Both approaches have advantages and disadvantages. When provided with temporally continuous atmospheric forcing data, prognostic models offer continuous sub-daily ET information together with the full set of water and energy balance fluxes and states (i.e. soil moisture, runoff, sensible and latent heat). On the other hand, the diagnostic modeling approach provides ET estimates over regions where reliable information about available soil water is not known (e.g., due to irrigation practices or shallow ground water levels not included in the prognostic model structure, unknown soil texture or plant rooting depth, etc). Prognostic model-based ET estimates are of great interest whenever consistent and complete water budget information is required or when there is a need to project ET for climate or land use change scenarios. Diagnostic models establish a stronger link to remote sensing observations, can be applied in regions with limited or questionable atmospheric forcing data, and provide valuable observation-derived information about the current land-surface state. Analysis of independently obtained ET estimates is particularly important in data poor regions. Such comparisons can help to reduce the uncertainty in the modeled ET estimates and to exclude outliers based on physical considerations. The Nile river basin is home to tens of millions of people whose daily life depends on water extracted from the river Nile. Yet the complete basin scale water balance of the Nile has been studied only a few times, and the temporal and the spatial distribution of hydrological fluxes (particularly ET) are still a subject of active research. This is due in part to a scarcity of ground-based station data for validation. In such regions, comparison between prognostic and diagnostic model output

  4. Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene

    PubMed Central

    Blanchet, Cécile L.; Frank, Martin; Schouten, Stefan

    2014-01-01

    The termination of the African Humid Period in northeastern Africa during the early Holocene was marked by the southward migration of the rain belt and the disappearance of the Green Sahara. This interval of drastic environmental changes was also marked by the initiation of food production by North African hunter-gatherer populations and thus provides critical information on human-environment relationships. However, existing records of regional climatic and environmental changes exhibit large differences in timing and modes of the wet/dry transition at the end of the African Humid Period. Here we present independent records of changes in river runoff, vegetation and erosion in the Nile River watershed during the Holocene obtained from a unique sedimentary sequence on the Nile River fan using organic and inorganic proxy data. This high-resolution reconstruction allows to examine the phase relationship between the changes of these three parameters and provides a detailed picture of the environmental conditions during the Paleolithic/Neolithic transition. The data show that river runoff decreased gradually during the wet/arid transition at the end of the AHP whereas rapid shifts of vegetation and erosion occurred earlier between 8.7 and ∼6 ka BP. These asynchronous changes are compared to other regional records and provide new insights into the threshold responses of the environment to climatic changes. Our record demonstrates that the degradation of the environment in northeastern Africa was more abrupt and occurred earlier than previously thought and may have accelerated the process of domestication in order to secure sustainable food resources for the Neolithic African populations. PMID:25551633

  5. Asynchronous changes in vegetation, runoff and erosion in the nile river watershed during the holocene.

    PubMed

    Blanchet, Cécile L; Frank, Martin; Schouten, Stefan

    2014-01-01

    The termination of the African Humid Period in northeastern Africa during the early Holocene was marked by the southward migration of the rain belt and the disappearance of the Green Sahara. This interval of drastic environmental changes was also marked by the initiation of food production by North African hunter-gatherer populations and thus provides critical information on human-environment relationships. However, existing records of regional climatic and environmental changes exhibit large differences in timing and modes of the wet/dry transition at the end of the African Humid Period. Here we present independent records of changes in river runoff, vegetation and erosion in the Nile River watershed during the Holocene obtained from a unique sedimentary sequence on the Nile River fan using organic and inorganic proxy data. This high-resolution reconstruction allows to examine the phase relationship between the changes of these three parameters and provides a detailed picture of the environmental conditions during the Paleolithic/Neolithic transition. The data show that river runoff decreased gradually during the wet/arid transition at the end of the AHP whereas rapid shifts of vegetation and erosion occurred earlier between 8.7 and ∼6 ka BP. These asynchronous changes are compared to other regional records and provide new insights into the threshold responses of the environment to climatic changes. Our record demonstrates that the degradation of the environment in northeastern Africa was more abrupt and occurred earlier than previously thought and may have accelerated the process of domestication in order to secure sustainable food resources for the Neolithic African populations.

  6. Water Security and Hydropolitics of the Nile River: South Sudan’s National Security in the 21st Century

    DTIC Science & Technology

    2011-12-16

    OdwNU8cs NKAC&oi=fnd&pg=PA20&dq=Facing+Global+Environmental+Change:+ Enviro nmental,+ Human ,+Energy,+Food,+Health,+and+Water+Security+Concepts&ots......Egyptians, has often centered around protecting livelihood in the event the Nile River stops flowing, or its direction of flow is diverted. 6 This fear

  7. Detection of West Nile virus in wild birds in Tana River and Garissa Counties, Kenya.

    PubMed

    Nyamwaya, Doris; Wang'ondu, Virginia; Amimo, Joshua; Michuki, George; Ogugo, Moses; Ontiri, Enoch; Sang, Rosemary; Lindahl, Johanna; Grace, Delia; Bett, Bernard

    2016-11-23

    West Nile fever virus is a zoonotic arboviral infection maintained in a sylvatic cycle involving mosquito vectors and birds. It is one the arboviruses whose geographical range is expanding because of climate and land use changes that enhance the densities of mosquitoes and promote mosquito-bird-human interactions. We carried out a survey to determine the reservoirs of WNV among wild birds in Tana River and Garissa counties, Kenya. Blood samples were obtained from 361 randomly trapped wild birds. Using real-time polymerase chain reaction (PCR), all samples were screened for WNV using gene specific primer sets amplifying a portion of the E region of the genome encoding the envelope protein. Sixty five (65) out of 361 birds screened tested positive for WNV on real-time PCR assay. Sequencing of the selected positive samples reveals that the isolated WNV were most closely related to strains isolated from China (2011). A regression analysis indicated that sampling location influenced the occurrence of WNV while species, age, weight and sex of the birds did not have any effect. This study provides baseline information on the existing circulation of WNV in this region among wild bird reservoirs that could spill over to the human population and points to the need for implementation of surveillance programs to map the distribution of the virus among reservoirs. Awareness creation about West Nile fever in this region is important to improve its detection and management.

  8. Modeling the Impact of controlled flow and sediment releases for the restoration of the Nile River-Delta system, Egypt

    NASA Astrophysics Data System (ADS)

    Al-Zaidi, B.; Moussa, A.; Viparelli, E.

    2016-12-01

    The construction of the High Aswan Dam (HAD) and river barrages significantly modified the flow and the sediment transport regimes in the Egyptian portion of the Nile River. Field data of the Nile Research Institute reveal that flood flows are reduced more than 70% compared to pre-HAD conditions and more than 98% of the sediment load is trapped in Lake Nasser upstream of the HAD. Water diversions at the barrages further reduce the flow rate reaching the Nile delta. Consequences of the flow regulation are erosion of the channel bed and changes in channel morphology in the upstream part of the study reach, and in-channel sedimentation in the downstream part of the system. However, due to the flow reduction, the sediment load delivered to the Mediterranean Sea is negligible compared to pre-dam conditions with consequent delta wide wetland loss and shoreline retreat. Here we present the first part of a feasibility study for the restoration of the Nile River-delta system characterized by controlled flow releases and sediment augmentations downstream of the HAD. The controlled flow releases are obtained by combining the current releases form the High Aswan Dam with a 10 billion m3 annual hydrograph. Previous studies showed that this volume of water will be available if the irrigation canals are replaced by more water efficient irrigation methods. The objectives of this work are to quantify the effects of the restoration project in terms of 1) erosion in the upstream part of the study reach, 2) sedimentation in the downstream part of the study reach, and 3) flow rate and sediment load delivered to the delta apex during the restoration project. The impacts of the controlled flow and sediment releases on the Nile River delta will be quantified in the near future.

  9. "Nile River Delta, Cairo and the Pyramids taken from Atlantis during STS-106"

    NASA Image and Video Library

    2000-09-09

    STS106-701-025 (8-20 September 2000) --- One of the STS-106 crew members on board the Space Shuttle Atlantis used a handheld 70mm camera to photograph this image of Cairo, Egypt, the largest city in Africa. Its population is nearly 16 million, a figure which translates to approximately 130,000 people per square mile. Metropolitan Cairo shows as a gray area in the green of the Nile River valley at the apex of the Delta. The shadows of the three major pyramids at Giza on the Western edge of the city are visible. They are right below the bright new road construction. This side of the metropolitan area is experiencing rapid growth. According to geologists who have been studying shuttle-to-Earth imagery for many years, this photograph documents some of the many changes in land use in the Western Desert.

  10. Risk assessment of polychlorinated biphenyls (PCBs) and trace metals in River Nile up- and downstream of a densely populated area.

    PubMed

    Omar, Wael A; Mahmoud, Hamada M

    2017-02-01

    Cairo city is the largest populated area along the whole course of River Nile with a wide range of anthropogenic activities. Efforts to restore fish habitat and recreational use of the river have raised concerns about its water, sediment and biota quality. This study provides a baseline data on the levels of PCBs and trace metals in River Nile along Cairo sector and implements the formulation of monitoring activities of the river's pollution status. Water, sediment and Nile tilapia (Oreochromis niloticus) samples were collected during summer season, 2013 from two sites, up- and downstream, for detection and determination of 11 PCB congeners (PCBs 28, 44, 52, 70, 101, 105, 118, 138, 152, 180 and 192) as well as six trace metals (Cu, Zn, Mn, Cd, Pb and Fe). Evidences of long- or short-term exposures to these contaminants as well as its accumulation tendency were assessed by integrating the obtained analytical results of biotic and abiotic components of this aquatic ecosystem. All calculated lifetime cancer risk values for PCBs showed unacceptable risk of cancer for human consumers at both normal and subsistence fish consumption rates. The calculated hazard index for total PCBs indicates that fish are not safe for human consumption except in site 1 at normal consumption rate. Meanwhile, trace metals do not pose unacceptable risks at both consumption rates except for Pb in site 1 at subsistence consumption rate.

  11. Integral view of Holocene precipitation and vegetation changes in the Nile catchment area as inferred from its delta sediments

    NASA Astrophysics Data System (ADS)

    Hennekam, Rick; Donders, Timme H.; Zwiep, Karin; de Lange, Gert J.

    2015-12-01

    We compare geochemical and pollen data of several well-dated, high-resolution cores to provide an integral Holocene overview of Nile outflow, sedimentation, and vegetation in and around the Nile delta. We show that the focus point of the Nile plume varied considerably, as indicated by planktonic foraminifer Globigerinoides ruber oxygen isotopes tracing Nile discharge differences in an east-west delta transect. At 13-11.5 cal kyr BP, Nile discharge was low and runoff was predominantly directed to the western part of the delta. Sediment arriving in the delta during that period was dominated by Ethiopian Highland (∼Blue Nile) material, shown by high Ti/Al values of the bulk sediment, indicating dry conditions in the source area of the Blue Nile. Nile discharge increased from ∼11.5 cal kyr BP, and was high across the whole delta from ∼10-6.5 cal kyr BP. During this time, the Ti/Al values decreased within most Nile-delta sediments, suggesting that the relative contribution of Blue-Nile sediment decreased. This was likely due to an increased vegetation cover causing diminished erosion in the Ethiopian Highlands. Nile discharge gradually decreased from ∼6.5 cal kyr BP to present. This decrease was more abrupt in the Western Province of the delta and became more gradual towards the east as the shrinking Nile runoff was directed there. The gradual decrease in precipitation in the Nile catchment area seems not to be matched by a gradual response in vegetation growing around the river plain in the lower Nile catchment. Our findings suggest a nonlinear response of northeast African vegetation to precipitation from the middle to late Holocene.

  12. Shifting Sediment Sources in the Quaternary Nile

    NASA Astrophysics Data System (ADS)

    Woodward, Jamie; Macklin, Mark; Fielding, Laura; Millar, Ian; Williams, Martin

    2016-04-01

    Invited Paper The Nile basin contains the longest river channel system in the world and drains about one tenth of the African continent. A dominant characteristic of the modern Nile is the marked spatial and temporal variability in the flux of water and sediment. Because the major headwater basins of the Nile are linked to key elements of the global climate system, the sedimentary records in the basin have attracted good deal of attention from the Quaternary palaeoclimate and palaeohydrology communities. Various approaches (from heavy minerals to strontium isotopes) have been employed to examine present and past patterns of sediment yield in the basin. A good deal of work has been carried out on the long sediment records in the delta and offshore which provide high resolution archives of hydrological changes in the upstream basin as well fluctuations in the input of dust from the desert. The sediment load of the modern desert Nile (downstream of Khartoum) is dominated by sediment inputs from the Blue Nile (61 +/- 5%) and Atbara (35 +/- 4%), whilst the White Nile contribution is meagre (3 +/- 2%) (Padoan et al. 2011). Recent work has shown that these values were very different during humid phases of the Quaternary when stronger Northern Hemisphere summer insolation produced wetter conditions across North Africa. In the early Holocene, for example, the Nile floodplain in Northern Sudan shows a tributary wadi input of 40-50%. This paper will review three decades of work on the sediment delivery dynamics of the Quaternary Nile and explore their palaeoclimatic implications. Padoan, M., Garzanti, E., Harlavan, Y., Villa, I.M. (2011) Tracing Nile sediment sources by Sr and Nd isotope signatures (Uganda, Ethiopia, Sudan). Geochim. Cosmochim. Acta 75 (12), 3627-3644.

  13. Comparison of prognostic and diagnostic surface flux modeling approaches over the Nile River basin

    NASA Astrophysics Data System (ADS)

    Yilmaz, M. Tugrul; Anderson, Martha C.; Zaitchik, Ben; Hain, Chris R.; Crow, Wade T.; Ozdogan, Mutlu; Chun, Jong Ahn; Evans, Jason

    2014-01-01

    Regional evapotranspiration (ET) can be estimated using diagnostic remote sensing models, generally based on principles of energy balance closure, or with spatially distributed prognostic models that simultaneously balance both energy and water budgets over landscapes using predictive equations for land surface temperature and moisture states. Each modeling approach has complementary advantages and disadvantages, and in combination they can be used to obtain more accurate ET estimates over a variety of land and climate conditions, particularly for areas with limited ground truth data. In this study, energy and water flux estimates from diagnostic Atmosphere-Land Exchange (ALEXI) and prognostic Noah land surface models are compared over the Nile River basin between 2007 and 2011. A second remote sensing data set, generated with Penman-Monteith approach as implemented in the Moderate Resolution Imaging Spectroradiometer (MODIS) MOD16 ET product, is also included as a comparative technique. In general, spatial and temporal distributions of flux estimates from ALEXI and Noah are similar in regions where the climate is temperate and local rainfall is the primary source of water available for ET. However, the diagnostic ALEXI model is better able to retrieve ET signals not directly coupled with the local precipitation rates, for example, over irrigated agricultural areas or regions influenced by shallow water tables. These hydrologic features are not well represented by either Noah or MOD16. Evaluation of consistency between diagnostic and prognostic model estimates can provide useful information about relative product skill, particularly over regions where ground data are limited or nonexistent as in the Nile basin.

  14. Value versus Accuracy: application of seasonal forecasts to a hydro-economic optimization model for the Sudanese Blue Nile

    NASA Astrophysics Data System (ADS)

    Satti, S.; Zaitchik, B. F.; Siddiqui, S.; Badr, H. S.; Shukla, S.; Peters-Lidard, C. D.

    2015-12-01

    The unpredictable nature of precipitation within the East African (EA) region makes it one of the most vulnerable, food insecure regions in the world. There is a vital need for forecasts to inform decision makers, both local and regional, and to help formulate the region's climate change adaptation strategies. Here, we present a suite of different seasonal forecast models, both statistical and dynamical, for the EA region. Objective regionalization is performed for EA on the basis of interannual variability in precipitation in both observations and models. This regionalization is applied as the basis for calculating a number of standard skill scores to evaluate each model's forecast accuracy. A dynamically linked Land Surface Model (LSM) is then applied to determine forecasted flows, which drive the Sudanese Hydroeconomic Optimization Model (SHOM). SHOM combines hydrologic, agronomic and economic inputs to determine the optimal decisions that maximize economic benefits along the Sudanese Blue Nile. This modeling sequence is designed to derive the potential added value of information of each forecasting model to agriculture and hydropower management. A rank of each model's forecasting skill score along with its added value of information is analyzed in order compare the performance of each forecast. This research aims to improve understanding of how characteristics of accuracy, lead time, and uncertainty of seasonal forecasts influence their utility to water resources decision makers who utilize them.

  15. Comparative evaluation of different satellite rainfall estimation products and bias correction in the Upper Blue Nile (UBN) basin

    NASA Astrophysics Data System (ADS)

    Abera, Wuletawu; Brocca, Luca; Rigon, Riccardo

    2016-09-01

    In a region where ground-based gauge data are scarce, satellite rainfall estimates (SREs) are a viable option for proper space-time rainfall characterization. However, their accuracy and performances vary from region to region, and must be assessed. In this study, five high resolution satellite products (3B42V7, CMORPH, TAMSAT, SM2R-CCI, and CFSR) are compared and analyzed using the available rain gauge data in one of the most topographically and climatologically complex basin of Africa, the Upper Blue Nile basin (UBN). The basin rainfall is investigated systematically, and it is found that, at some locations, the difference in mean annual rainfall estimates between these SREs could be as much as about 2700 mm. Considering three goodness-of-fit indexes, correlation, bias and root mean square error (RMSE) between the SREs and ground-based gauge rainfall, CMORPH, TAMSAT and SM2R-CCI outperform the other two. Furthermore, a confusion matrix is used to investigate the detection ability of satellite rainfall products for different rainfall intensities. TAMSAT has the highest (91%) detection skill for dry days, followed by CFSR (77%). On the contrary, SM2R-CCI has the highest accuracy index for medium rainfall ranges (10-20 mm). The empirical cumulative distribution (ecdf) mapping technique is used to correct the intensities distribution givenby the SREs. This method provides a means to improve the rainfall estimation of all SREs, and the highest improvement is obtained for CMORPH (bias reduction from - 72% to - 1%).

  16. Complete mitochondrial DNA sequences of the Nile tilapia (Oreochromis niloticus) and Blue tilapia (Oreochromis aureus): genome characterization and phylogeny applications.

    PubMed

    He, Anyuan; Luo, Yongju; Yang, Hong; Liu, Liping; Li, Sifa; Wang, Chenghui

    2011-03-01

    Cichlid fishes have played an important role in evolutionary biology and aquaculture industry. Nile tilapia (Oreochromis niloticus), blue tilapia (Oreochromis aureus) and Mozambique tilapia (Oreochromis mossambicus), the useful models in studying evolutionary biology within Cichlid fishes, are also mainly cultured species in aquaculture with great economic importance. In this paper, the complete nucleotide sequence of the mitochondrial genome for O. niloticus and O. aureus were determined and phylogenetic analyses from mitochondrial protein-coding genes were conducted to explore their phylogenetic relationship within Cichlids. The mitogenome is 16,625 bp for O. niloticus and 16,628 bp for O. aureus, containing the same gene order and an identical number of genes or regions with the other Cichlid fishes, including 13 protein-coding genes, two rRNA genes, 22 tRNA genes and one putative control region. Phylogenetic analyses using three different computational algorithms (maximum parsimony, maximum likelihood and Bayesian method) show O. niloticus and O. mossambicus are closely related, and O. aureus has remotely phylogenetic relationship from above two fishes.

  17. Label-free electrochemical immunosensor based on Nile blue A-reduced graphene oxide nanocomposites for carcinoembryonic antigen detection.

    PubMed

    Gao, Yan-Sha; Zhu, Xiao-Fei; Xu, Jing-Kun; Lu, Li-Min; Wang, Wen-Min; Yang, Tao-Tao; Xing, Hua-Kun; Yu, Yong-Fang

    2016-05-01

    In this article, a novel, label-free, and inherent electroactive redox immunosensor for carcinoembryonic antigen (CEA) based on gold nanoparticles (AuNPs) and Nile blue A (NB) hybridized electrochemically reduced graphene oxide (NB-ERGO) is proposed. The composite of NB-graphene oxide (NB-GO) was prepared by π-π stacking interaction. Then, chronoamperometry was adopted to simultaneously reduce HAuCl4 and nanocomposites of NB-GO for synthesizing AuNPs/NB-ERGO. The immunosensor was fabricated by capturing CEA antibody (anti-CEA) at this nanocomposite modified electrode. The immunosensor determination was based on the fact that, due to the formation of antigen-antibody immunocomplex, the decreased response currents of NB were directly proportional to the concentrations of CEA. Under optimal conditions, the linear range of the proposed immunosensor was estimated to be from 0.001 to 40 ng ml(-1) and the detection limit was estimated to be 0.00045 ng ml(-1). The proposed immunosensor was used to determine CEA in clinical serum samples with satisfactory results. The proposed method may provide promising potential application in clinical immunoassays with the properties of facile procedure, stability, high sensitivity, and selectivity.

  18. Thermal cycling and the optical and electrical characterization of self-assembled multilayer Nile Blue A-gold thin films

    SciTech Connect

    Geist, Brian; Spillman, William B.; Claus, Richard O

    2005-10-20

    Some laser applications produce high power densities that can be dangerous to equipment and operators. We have fabricated thin-film coatings by using molecular electrostatic self-assembly to create a spectrally selective absorbing coating that is able to withstand thermal fluctuations from -20 deg. C to 120 deg. C. We made the thin-film coatings by alternating deposition of an organic dye and gold colloidal nanoparticles onto glass substrates. Nile Blue A perchlorate, with a maximum absorbance slightly above 632 nm, was chosen as the organic dye. Strong coupling between the dye molecules and the gold nanoparticles provides a redshift that increases as the film's thickness is increased. The incorporation of the gold colloidal nanoparticles also decreases the resistivity of the film. The resistivity of the film was measured with a four-point probe and found to be {approx}10 {omega}/cm for the two samples measured. Atomic-force microscopy was used to show that film thickness increased 2.4nm per bilayer. The optical properties of the film were measured at the end of every 5 thermal cycles from -20 deg. C to 120 deg. C, and negligible degradation was observed after 30 cycles.

  19. Thermal cycling and the optical and electrical characterization of self-assembled multilayer nile blue A-gold thin films.

    PubMed

    Geist, Brian; Spillman, William B; Claus, Richard O

    2005-10-20

    Some laser applications produce high power densities that can be dangerous to equipment and operators. We have fabricated thin-film coatings by using molecular electrostatic self-assembly to create a spectrally selective absorbing coating that is able to withstand thermal fluctuations from -20 degrees C to 120 degrees C. We made the thin-film coatings by alternating deposition of an organic dye and gold colloidal nanoparticles onto glass substrates. Nile Blue A perchlorate, with a maximum absorbance slightly above 632 nm, was chosen as the organic dye. Strong coupling between the dye molecules and the gold nanoparticles provides a redshift that increases as the film's thickness is increased. The incorporation of the gold colloidal nanoparticles also decreases the resistivity of the film. The resistivity of the film was measured with a four-point probe and found to be approximately 10 omega/cm for the two samples measured. Atomic-force microscopy was used to show that film thickness increased 2.4 nm per bilayer. The optical properties of the film were measured at the end of every 5 thermal cycles from -20 degrees C to 120 degrees C, and negligible degradation was observed after 30 cycles.

  20. Thermal cycling and the optical and electrical characterization of self-assembled multilayer Nile Blue A gold thin films

    NASA Astrophysics Data System (ADS)

    Geist, Brian; Spillman, William B.; Claus, Richard O.

    2005-10-01

    Some laser applications produce high power densities that can be dangerous to equipment and operators. We have fabricated thin-film coatings by using molecular electrostatic self-assembly to create a spectrally selective absorbing coating that is able to withstand thermal fluctuations from -20 °C to 120 °C. We made the thin-film coatings by alternating deposition of an organic dye and gold colloidal nanoparticles onto glass substrates. Nile Blue A perchlorate, with a maximum absorbance slightly above 632 nm, was chosen as the organic dye. Strong coupling between the dye molecules and the gold nanoparticles provides a redshift that increases as the film's thickness is increased. The incorporation of the gold colloidal nanoparticles also decreases the resistivity of the film. The resistivity of the film was measured with a four-point probe and found to be ˜10 Ω/cm for the two samples measured. Atomic-force microscopy was used to show that film thickness increased 2.4nm per bilayer. The optical properties of the film were measured at the end of every 5 thermal cycles from -20 °C to 120 °C, and negligible degradation was observed after 30 cycles.

  1. The Nile

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of the northern portion of the Nile River was captured by MISR's nadir camera on January 30, 2001 (Terra orbit 5956). The Nile is the longest river in the world, extending for about 6700 kilometers from its headwaters in the highlands of eastern Africa.

    At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to the east.

    Also visible in this image is the Suez Canal, a shipping waterway connecting Port Said on the Mediterranean Sea with the Gulf of Suez. The Gulf is an arm of the Red Sea, and is located on the righthand side of the picture.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  2. The Nile

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of the northern portion of the Nile River was captured by MISR's nadir camera on January 30, 2001 (Terra orbit 5956). The Nile is the longest river in the world, extending for about 6700 kilometers from its headwaters in the highlands of eastern Africa.

    At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to the east.

    Also visible in this image is the Suez Canal, a shipping waterway connecting Port Said on the Mediterranean Sea with the Gulf of Suez. The Gulf is an arm of the Red Sea, and is located on the righthand side of the picture.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  3. Water Dynamics in Fogera and the Upper Blue Nile - Farmers perspectives and remote sensing

    NASA Astrophysics Data System (ADS)

    Chemin, Yann; Desalegn, Mengistu; Curnow, Jayne; Johnston, Robyn

    2015-04-01

    This research work is about finding the connection between farmers perspectives on changes of water conditions in their socio-agricultural environment and satellite remote sensing analysis. Key informant surveys were conducted to investigate localised views on water scarcity as a counterpoint to the physical measurement of water availability. Does a numerical or mapped image identifying water scarcity always equate to a dearth of water for agriculture? To push the limits of the relationship between human and physical data we sought to ground-truth GIS results with the practical experience and knowledge of people living in the area. We data-mined public domain satellite data with FOSS (GDAL, GRASS GIS) and produced water-related spatio-temporal domains for our study area and the larger Upper Nile Basin. Accumulated remote sensing information was then cross-referenced with informant's accounts of water availability for the same space and time. During the survey fieldwork the team also took photographs electronically stamped with GPS coordinates to compare and contrast the views of informants and the remote sensing information with high resolution images of the landscape. We found that farmers perspective on the Spring maize crop sensibility to variability of rainfall can be quantified in space and time by remote sensing cumulative transpiration. A crop transpiration gap of 1-2.5 mm/day for about 20 days is to be overcome, a full amount of 20 to 50 mm, depending on the type of year deficit. Such gap can be overcome, even by temporary supplemental irrigation practices, however, the economical and cultural set up is already developed in another way, as per sesonal renting of higher soil profile water retention capacity fields.

  4. Evaluation of high resolution global satellite precipitation products using daily raingauge data over the Upper Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Sahlu, Dejene; Moges, Semu; Anagnostou, Emmanouil; Nikolopoulos, Efthymios; Hailu, Dereje; Mei, Yiwen

    2017-04-01

    Water resources assessment, planning and management in Africa is often constrained by the lack of reliable spatio-temporal rainfall data. Satellite products are steadily growing and offering useful alternative datasets of rainfall globally. The aim of this paper is to examine the error characteristics of the main available global satellite precipitation products with the view of improving the reliability of wet season (June to September) and small rainy season rainfall datasets over the Upper Blue Nile Basin. The study utilized six satellite derived precipitation datasets at 0.25-deg spatial grid size and daily temporal resolution:1) the near real-time (3B42_RT) and gauge adjusted (3B42_V7) products of Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), 2) gauge adjusted and unadjusted Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) products and 3) the gauge adjusted and un-adjusted product of the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center Morphing technique (CMORPH) over the period of 2000 to 2013.The error analysis utilized statistical techniques using bias ratio (Bias), correlation coefficient (CC) and root-mean-square-error (RMSE). Mean relative error (MRE), CC and RMSE metrics are further examined for six categories of 10th, 25th, 50th, 75th, 90thand 95th percentile rainfall thresholds. The skill of the satellite estimates is evaluated using categorical error metrics of missed rainfall volume fraction (MRV), falsely detected rainfall volume fraction (FRV), probability of detection (POD) and False Alarm Ratio (FAR). Results showed that six satellite based rainfall products underestimated wet season (June to September) gauge precipitation, with the exception of non-adjusted PERSIANN that overestimated the initial part of the rainy season (March to May). During the wet season, adjusted CMORPH has relatively better bias ratio (89

  5. A dual-wavelength overlapping resonance Rayleigh scattering method for the determination of chondroitin sulfate with nile blue sulfate

    NASA Astrophysics Data System (ADS)

    Cui, Zhiping; Hu, Xiaoli; Liu, Shaopu; Liu, Zhongfang

    2011-12-01

    A dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) method was developed to detect chondroitin sulfate (CS) with nile blue sulfate (NBS). At pH 3.0-4.0 Britton-Robinson (BR) buffer medium, CS interacted with NBS to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS), second order scattering (SOS) and frequence doubling scattering (FDS) appeared and their intensities were enhanced greatly. Their maximum wavelengths were located at 303 nm (RRS), 362 nm (RRS), 588 nm (SOS) and 350 nm (FDS), respectively. The scattering intensities of the three methods were proportional to the concentration of CS in certain ranges. The methods had high sensitivity and the detection limits were between 1.5 and 7.1 ng mL -1. The DWO-RRS method had the highest sensitivity with the detection limit being 1.5 ng mL -1. The characteristics of the spectra and optimal reaction conditions of RRS method were investigated. The effects of coexistent substances on the determination of CS were evaluated. Owing to the high sensitivity, RRS method had been applied to the determination of CS in eye drops with satisfactory results. The recovery range was between 99.4% and 104.6% and the relative standard deviation (RSD) was between 0.4% and 0.8%. In addition, the reasons for RRS enhancement were discussed and the shape of ion-association complex was characterized by atomic force microscopy (AFM).

  6. Linking soil erosion to on-site financial cost: lessons from watersheds in the Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Erkossa, T.; Wudneh, A.; Desalegn, B.; Taye, G.

    2015-06-01

    The study was conducted in three watersheds (Dapo, Meja and Mizewa) in the Ethiopian part of the Blue Nile Basin to estimate the on-site cost of soil erosion using the productivity change approach, in which crop yield reduction due to plant nutrients lost with the sediment and runoff has been analysed. For this purpose, runoff measurement and sampling was conducted during the main rainy season of 2011 at the outlet of two to three sub-watersheds in each watershed. The sediment concentration of the runoff, and N and P contents in runoff and sediment were determined. Crop response functions were developed for the two plant nutrients based on data obtained from the nearest Agricultural Research Centres. The response functions were used to estimate crop yield reduction as a result of the lost N and P assuming there is no compensation through fertilization. The results show a significant yield reduction and resultant financial loss to the farmers. Considering only grain yield of maize (Zea mays), farmers at Dapo annually lose about USD 220 ha-1 and 150 ha-1 due to the loss of N and P, respectively. In view of the importance of the crop residues, including as feed, the loss can be even greater. The study demonstrated that in addition to the long-term deterioration of land quality, the annual financial loss suffered by farmers is substantial. Therefore, on farm soil and water conservation measures that are suitable in biophysical and socio-economic terms in the landscapes and beyond need to be encouraged.

  7. Assessing Impact of Climate Change on the Runoffs of Gilgel Abbay Watershed, the upper Blue Nile Basin, Ethiopia

    NASA Astrophysics Data System (ADS)

    Ayele, H. S.; Li, M. H.; Tung, C. P.; Liu, T. M.

    2015-12-01

    Water is the most climate sensitive sector in changing climate. Hydrological vulnerability assessment is critical to the implementation of adaption measures. In this study, projections of 7 GCMs in association with high (RCP8.5) and medium low (RCP4.5) representative concentration path way from the CMPI5 (fifth phase of the Coupled Model Intercomparison Project) for the period 2021-2040 and 2081-2100 were adopted to assess the impacts of climate change on the runoffs of Gilgel Abbay watershed, the upper Blue Nile basin, in Ethiopia. The GCMs selected were first screened in harmony with baseline climate statistics of study areas. Based on climate projections and statistical characteristics of historical weather data, a weather generator was employed to generate daily temperature and precipitation as inputs for the GWLF hydrological model to simulate runoffs. Changes of projected temperature and precipitation were analyzed to explain variations of evapotranspiration and influences on future runoffs. We found that, despite the fact that the projected magnitude varies among different GCMs, increasing in the wet and a decreasing in dry seasons runoffs were observed in both time windows, which mainly attributes to the increase of precipitations projected by most of GCMs. In contrast to great increases in runoffs, the increase of evapotranspiration by elevating temperature is less significant. The increasing runoffs in both time windows will provide more water inflow to the Lake Tana. On the other hand, the increase of precipitation in wet season makes the wet season wetter and implies higher possibility of flash floods. This will have deleterious consequences in the local community. Therefore, concerned water organizations in local, state, and federal levels shall be prepared to harness the opportunities with more water resources for utilization and management, as well as flood preventive measures.

  8. Effect of water vapors on the luminescence of cation-exchange membranes modified by Pt(II) and Ru(II) complexes and Nile blue

    NASA Astrophysics Data System (ADS)

    Khakhalina, M. S.; Musaeva, D. N.; Tikhomirova, I. Yu.; Puzyk, M. V.

    2010-04-01

    The surface of a cation-exchange membrane was modified by the [PtEnPpy]+, [PtEnBt]+, [PtEnTpy]+, [RuBpy3]+2, and NB+, (En is ethylenediamine; Ppy, Bt, Tpy are α-deprotonated forms of 2-phenylpyridine, 2-phenylbenzothiazole, and 2-(2'-thienyl)pyridine, respectively; Bpy is 2,2'-bipyridyl, and NB+ is Nile blue) ions, which exhibit intense luminescence. It is found that the quenching of the luminescence of the modified cation-exchange membrane by water vapors depends on the nature of the excited electronic state of the immobilized cation.

  9. Paleoclimate of the Eastern Mediterranean/North Africa during the past 26 cal ka based on organic geochemical investigations of a Nile River Delta sediment core

    NASA Astrophysics Data System (ADS)

    Castaneda, I. S.; Schefuss, E.; Patzold, J.; Sinninghe Damste, J. S.; Schouten, S.

    2007-12-01

    The Mediterranean Sea is situated within a highly sensitive climatic region, which is influenced by both tropical and mid-latitude climate dynamics, and the paleoenvironmental history of this region is of interest because large human populations occupy the surrounding landmasses. In this study, multiple organic geochemical proxies are examined from a Nile River Delta sediment core (GeoB 7702-3) to investigate the paleoclimatic history of the North Africa/Eastern Mediterranean region during the past ~26 cal ka. Sea surface temperatures were reconstructed using both the TEX86 and alkenone paleothermometers. The TEX86 record exhibits centennial to millennial scale variability and captures global climate events including the Last Glacial Maximum (LGM), Heinrich Event 1 (H1), the Bolling/Allerod and the Younger Dryas (YD). The recently developed Branched and Isoprenoid Tetraether (BIT) index, used to differentiate between marine and terrestrial inputs, closely tracks changes noted in bulk C/N ratios. Overall, these records indicate greater variability during the Late Pleistocene than during the Holocene, with the highest terrestrial inputs noted at approximately the time of the YD and prior to H1. Although it might be expected that fluvial organic matter inputs should be the lowest during the LGM, when the sources of both the Blue and White Nile were severely reduced or desiccated, higher (more terrestrial) BIT values noted at these times may be related to changes in vegetation cover in North Africa. During the Holocene, a major shift in the BIT index to lower (more marine) values marks the onset of deposition of the S1 sapropel layer. The lower BIT values noted during this interval are caused by a dramatic (order of magnitude) increase in the absolute abundance of crenarchaeol, attesting to enhanced marine productivity at this time. Following deposition of the S1 sapropel, absolute abundances of crenarchaeol are generally higher than during the Late Pleistocene

  10. N Isotopes in Nile Sediments (ethiopia, Sudan)

    NASA Astrophysics Data System (ADS)

    Padoan, M.; Villa, I. M.; Garzanti, E.; Galbusera, M.; Quistini, S.; Peruta, L.; El Kammar, A.

    2009-04-01

    The Nile is the most important river of the Eastern Mediterranean. Its water and sediment fluxes have greatly influenced marine circulation throughout the Quaternary, and are widely considered as possible causes for stagnation and formation of sapropel (Krom et al., 1999a; 2002; Talbot et al., 2000; Freydier et al., 2001; Weldeab et al., 2002; Scrivner et al., 2004). Variations in annual flooding and baseflow of the river Nile, controlled by climate changes, had major impact on the rise and demise of Egyptian dynasties (Stanley et al., 2003). In order to better define sedimentary sources of the Nile system and to obtain more robust results, we have analyzed Nd isotopes in sediments of all its major Sudanese and Ethiopian tributaries (Atbara, Gash, Abay, Didesa, Dabus, White Nile, Bahr Ez Zeraf) in several replicate samples. Analyses were carried out on distinct mud and sand fractions (<40 microns and 125-180 microns) of 30 samples, and systematic changes related to grain size and hydraulic-sorting processes could thus be investigated. On the same samples, companion studies are being carried out on Sr isotopes (Padoan et al., 2007) and on Pb isotopes at the Geological Survey of Israel (Harlavan et al., in preparation). Overall, isotopic signals are markedly different between the White Nile system, derived from largely Archean to Paleoproterozoic basement rocks, and Ethiopian tributaries, derived in diverse proportions from largely Neoproterozoic rift-shoulder basements and overlying Oligocene flood basalts. Isotopic signals of Main Nile sediments downstream of the Atbara confluence are close to those of Blue Nile sediments, indicating that detritus is mainly provided by the latter (Garzanti et al., 2006). In the White Nile branch, the 143Nd/144Nd ratio of the mud fraction is lower in the Bahr Ez Zeraf (0.51167) than in the White Nile downstrean of the Sobat confluence (0.51219), revealing significant sediment influx from the latter. In Blue Nile and Atbara branches

  11. Water balance dynamics in the Nile Basin

    USGS Publications Warehouse

    Senay, Gabriel B.; Asante, Kwabena; Artan, Guleid A.

    2009-01-01

    Understanding the temporal and spatial dynamics of key water balance components of the Nile River will provide important information for the management of its water resources. This study used satellite-derived rainfall and other key weather variables derived from the Global Data Assimilation System to estimate and map the distribution of rainfall, actual evapotranspiration (ETa), and runoff. Daily water balance components were modelled in a grid-cell environment at 0·1 degree (∼10 km) spatial resolution for 7 years from 2001 through 2007. Annual maps of the key water balance components and derived variables such as runoff and ETa as a percent of rainfall were produced. Generally, the spatial patterns of rainfall and ETa indicate high values in the upstream watersheds (Uganda, southern Sudan, and southwestern Ethiopia) and low values in the downstream watersheds. However, runoff as a percent of rainfall is much higher in the Ethiopian highlands around the Blue Nile subwatershed. The analysis also showed the possible impact of land degradation in the Ethiopian highlands in reducing ETa magnitudes despite the availability of sufficient rainfall. Although the model estimates require field validation for the different subwatersheds, the runoff volume estimate for the Blue Nile subwatershed is within 7·0% of a figure reported from an earlier study. Further research is required for a thorough validation of the results and their integration with ecohydrologic models for better management of water and land resources in the various Nile Basin ecosystems.

  12. Seasonal variation and enrichment of metals in sediments of Rosetta branch, Nile River, Egypt.

    PubMed

    Redwan, Mostafa; Elhaddad, Engy

    2016-06-01

    This study investigated heavy metal pollution in sediments of the Rosetta branch of the River Nile of Egypt to quantify the toxic distribution potential of metals into the surrounding environment. Sediment samples were collected at 9 sites during in four seasons. Organic matter and total metal concentrations were determined using loss on ignition and inductively coupled plasma spectrometry, respectively. Principal component analysis has been applied to evaluate the metal sources and the relationships between metals in sediments. Metal concentrations showed the following order: winter > autumn > spring > summer. Mean concentrations of Cu, Zn, Cd, and Pb in sediments were above the average background value of metals in shale. Pb and Cd showed higher enrichment during all seasons at stations N3/N4, Zn at stations N1 to N4, and Cu at stations N6/N8. The variations in heavy metal total concentration and organic matter are due to different input sources, physico-chemical conditions, and adsorption/precipitation/redox conditions in sediments. Mean values of Geo-accumulation index (Igeo) for Fe, Mn, and Cu were below 0 which were classified as unpolluted during spring, summer, and autumn, except Cu increased from unpolluted to moderately polluted during winter. Igeo values for Cd, Pb, and Zn increased from unpolluted-moderately polluted to highly-very highly polluted during autumn and winter. Pollution Load Index was recorded in highest values during winter, especially at Fuwwah/Basioun and in lowest values during summer at after the Edfina Barrage/before Kafer El-Zayat due to industrial/human activities. Both natural and anthropogenic sources contributed to the metal accumulations in sediments, and industrial, agricultural, and municipal sewage effluents discharged from non-point sources may be the main anthropogenic sources for metals in the Rosetta branch.

  13. Spatio-temporal variability of dissolved organic nitrogen (DON), carbon (DOC), and nutrients in the Nile River, Egypt.

    PubMed

    Badr, El-Sayed A

    2016-10-01

    Increases in human activity have resulted in enhanced anthropogenic inputs of nitrogen (N) and carbon (C) into the Nile River. The Damietta Branch of the Nile is subject to inputs from industrial, agricultural, and domestic wastewater. This study investigated the distribution and seasonality of dissolved organic nitrogen (DON), dissolved organic carbon (DOC), and nutrients in the Nile Damietta Branch. Water samples were collected from 24 sites between May 2009 and February 2010. Dissolved organic nitrogen concentrations averaged 251 ± 115 μg/l, with a range of 90.2-671 μg/l, and contributed 40.8 ± 17.7 % to the total dissolved nitrogen (TDN) pool. Relative to autumn and winter, DON was a larger fraction of the TDN pool during spring and summer indicating the influence of bacterioplankton on the nitrogen cycle. Concentrations of DOC ranged from 2.23 to 11.3 mg/l with an average of 5.15 ± 2.36 mg/l, reflecting a high organic matter load from anthropogenic sources within the study area, and were highest during autumn. Higher values of biochemical oxygen demand (BOD), chemical oxygen demand (COD), DON, nitrate, and phosphate occurred downstream of the Damietta Branch and were probably due to anthropogenic inputs to the Nile from the Damietta district. A bacterial incubation experiment indicated that 52.1-95.0 % of DON was utilized by bacteria within 21 days. The decrease in DON concentration was accompanied by an increase in nitrate concentration of 54.8-87.3 %, presumably through DON mineralization. Based on these results, we recommend that water quality assessments consider DON and DOC, as their omission may result in an underestimation of the total organic matter load and impact.

  14. How water reservoirs lift the blue water footprint cap for a river basin and reduce blue water scarcity: a case study for the Yellow River Basin

    NASA Astrophysics Data System (ADS)

    Zhuo, La; Hoekstra, Arjen Y.; Wu, Pute; Zhao, Xining

    2017-04-01

    The maximum sustainable blue water footprint in a river basin is limited by the part of precipitation that becomes runoff and by the need to maintain a minimum flow for sustaining ecosystems and livelihoods. A "blue water footprint cap" to be specified over time has been proposed as a policy instrument to set a maximum to the blue water footprint in a river basin. Reservoirs along the river help smoothing runoff variability and thus may reduce blue water scarcity during the dry season and increase the water footprint cap to be set for that period. Previous water scarcity studies, considering the ratio of actual to maximum sustainable blue water footprints have not included reservoir storages. In a case study for the Yellow River Basin (YRB), the current study estimates how water reservoirs lift the blue water footprint cap during the dry season and reduce blue water scarcity in this season. We schematize the YRB into three reaches (sub-basins), include five reservoirs along the main stream, and consider the period January 2002-August 2006. Results show that blue WF caps in all three reaches in the dry seasons with net water release from the reservoirs can be lifted substantially. In years with a net decrease in water storage over the year as a whole, the blue WF cap over the year can be lifted as well. The caps in the wet seasons with net water storage in the reservoirs get lower, but this is acceptable given the lower water demands in the wetter seasons. It is shown to which extent reservoir storage reduces blue water scarcity in every month and every reach of the YRB.

  15. Biological characteristics of the blue sucker in the James River and the Big Sioux River, South Dakota

    USGS Publications Warehouse

    Morey, N.M.; Berry, C.R.

    2003-01-01

    Little is known about the relative abundance and biology of the blue sucker (Cycleptus elongatus), a species that may be declining in some parts of its range. We described the age, growth, condition, length distribution, and habitat preference of the blue sucker in two South Dakota rivers. Specimens were collected from the James River (n=74) and Big Sioux River (n=28) during the summer of 2000. Although five macrohabitats were sampled with electrofishing and hoopnets, most individuals were collected from riffle habitats and downstream of rock dams. Total length-weight relationships were log10W=-6.14+3.37(log10L) (r2 = 0.92) for blue suckers from the James River and log10W = -6.52+3.50(log10L) (r2 = 0.97) for fish from the Big Sioux River. Mean condition factors (K = W(105)/L3) of blue suckers were 0.79 (SE = 0.07) for the James River and 0.73 (SE = 0.07) for the Big Sioux River. Blue suckers between 500 and 700 mm dominated length distributions (range = 374-717 mm) of both samples. Ages ranged from two to nine years, but six-year-old fish were captured most frequently. Blue suckers grew rapidly during juvenile stages (< age 5); however, growth slowed afterward.

  16. Major and trace element distribution in soil and sediments from the Egyptian central Nile Valley

    NASA Astrophysics Data System (ADS)

    Badawy, W. M.; Ghanim, E. H.; Duliu, O. G.; El Samman, H.; Frontasyeva, M. V.

    2017-07-01

    The distributions of 32 major and trace elements in 72 surface soil and sediment samples collected from the Asyut to Cairo Nile river section were determined by epithermal neutron activation analysis and compared with corresponding data for the Upper Continental Crust, North American Shale Composite, Average Soil and Average Sediment as well as suspended sediments from Congo and Upper Niger Rivers, in order to establish to which extent the Nile sedimentary material can be related to similar material all over the world as well as to local geology. Their relative distributions indicate the presence of detrital material of igneous origin, most probably resulting from weathering of the Ethiopian Highlands and transported by the Blue Nile, the Nile main tributary. The distributions of nickel, zinc, and arsenic contents suggest that the lower part of the Nile and its surroundings including the Nile Delta is not seriously polluted with heavy metals, so that, in spite of a human activity, which lasted four millennia, the Nile River continues to be less affected by any anthropogenic contamination.

  17. The Challenges and Opportunities of Hydrologic Remote Sensing in Data-Poor Regions: Case Study of Nile River Basin

    NASA Astrophysics Data System (ADS)

    Hasan, E.; Kirstetter, P.; Zhang, K.; Hong, Y.

    2015-12-01

    The Nile River Basin (NRB) is one of the largest trans-boundary watercourses; it is the lifeline for more than 300 million people belonging to 11 African nations sharing the NRB. The riparian countries are challenged by their infirm relationships, lack of information sharing and insufficient monitoring stations. Thus, to understand the water future along the NRB under the changing climate, reliable, and sufficient information are needed. This to assess and understand: whether will be more rainfall and induced flooding events, or the drought conditions with less surface runoff will be dominant over the Nile Basin? In addition, to what extent the available remote sensing and model reanalysis data can substitute the lack of detailed ground information, and help to determine the size and risk associated to the climatic impact on the Nile Basin? In the current study, we utilizing multi-scale remote sensing, and model reanalysis datasets for hydrologic monitoring along the NRB in Africa. The list of remote sensing, and model reanalysis datasets that implemented: several MODIS satellite products such as the NDVI, LAI, LST, and LULC datasets. Three GRACE satellite derivative products: TWS, EWT, and DTWS, and TRMM satellite precipitation product. In addition to number of model reanalysis datasets including Global Precipitation Climatological Center (GPCC) datasets, Global Land Data Assimilation System (GLDAS) products, Climate Research Unit (CRU) datasets, Physical Science Division (PSD) gridded climate dataset, and in situ Global Runoff Data Centre (GRDC) datasets. The main objective of our research is to monitor the hydrological changes and the variation in water balance along the NRB. The study approach accomplished through: (1) developing a distributed storage changes based grid, (2) trend analysis and inter-annual variability shift detections using regime shift analysis, (3) define the water stress and water deficit periods along the Nile Basins, (4) applying multi

  18. Prevalence and characterization of Cryptosporidium spp. in dairy cattle in Nile River delta provinces, Egypt.

    PubMed

    Amer, Said; Zidan, Shereif; Adamu, Haileeyesus; Ye, Jianbin; Roellig, Dawn; Xiao, Lihua; Feng, Yaoyu

    2013-11-01

    Molecular characterizations of Cryptosporidium spp. in dairy cattle in industrialized nations have mostly shown a dominance of Cryptosporidium parvum, especially its IIa subtypes in pre-weaned calves. Few studies, however, have been conducted on the distribution of Cryptosporidium species and C. parvum subtypes in various age groups of dairy cattle in developing countries. In this study, we examined the prevalence and molecular characteristics of Cryptosporidium in dairy cattle in four Nile River delta provinces in Egypt. Modified Ziehl-Neelsen acid-fast microscopy was used to screen for Cryptosporidium oocysts in 1974 fecal specimens from animals of different ages on 12 farms. Positive fecal specimens were identified from all studied farms with an overall prevalence of 13.6%. By age group, the infection rates were 12.5% in pre-weaned calves, 10.4% in post-weaned calves, 22.1% in heifers, and 10.7% in adults. PCR-RFLP and DNA sequence analyses of microscopy-positive fecal specimens revealed the presence of four major Cryptosporidium species. In pre-weaned calves, C. parvum was most common (30/69 or 43.5%), but Cryptosporidium ryanae (13/69 or 18.8%), Cryptosporidium bovis (7/69 or 10.2%), and Cryptosporidium andersoni (7/69 or 10.2%) were also present at much higher frequencies seen in most industrialized nations. Mixed infections were seen in 12/69 (17.4%) of genotyped specimens. In contrast, C. andersoni was the dominant species (193/195 or 99.0%) in post-weaned calves and older animals. Subtyping of C. parvum based on sequence analysis of the 60kDa glycoprotein gene showed the presence of subtypes IIdA20G1 in nine specimens, IIaA15G1R1 in 27 specimens, and a rare subtype IIaA14G1R1r1b in one specimen. The common occurrence of non-C. parvum species and IId subtypes in pre-weaned calves is a distinct feature of cryptosporidiosis transmission in dairy cattle in Egypt. The finding of the same two dominant IIa and IId C. parvum subtypes recently found in humans in

  19. Error analysis of global satellite precipitation products using daily gauged observations over the upper central Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Sahlu, Dejene; Moges, Semu; Anagnostou, Emmanouil N.; Hailu, Dereje

    2015-04-01

    Water resource assessment, planning and management in Africa are often constrained due to lack of reliable spatio-temporal rainfall data. Satellite and global reanalysis products are steadily growing and offering useful alternative datasets of rainfall globally. Aim of this paper is to examine the error characteristics of the main available global satellite precipitation products with the view to improve the reliability of wet season (June to September) rainfall datasets over the upper Blue Nile Basin in Ethiopia. The study utilized six satellite derived precipitation datasets at 0.25-deg spatial grid size and daily temporal resolution:1) the near real-time (3B42_RT) and gauge adjusted (3B42_V7) products of Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), 2) gauge adjusted and unadjusted Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) products and 3) the gauge adjusted and un-adjusted product of the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center Morphing technique (CMORPH) over the period of 2000 to 2013. The historical daily rainfall data sets are chosen for the same period from 64 gauging stations which are within a mountainous area of about 45,000 km2. The elevation of gauges used in this error study ranged from 1800 to 3000 meters above sea level. The error analysis utilized statistical techniques of missed rainfall volume fraction (MRV), falsely detected rainfall volume fraction (FRV), mean relative error (MRE), bias ratio (Bias), coefficient of variation of error (CVE) and the trends of the error metrics with respect to elevation. The three error metrics, MRE, Bias and CVE are further examined for five rainfall thresholds associated with different percentile categories (2nd, 20th, 50th, 80th and 98th) . Results show that CMORPH has relatively lower MRV (~1.5 %) than the TRMM and PERSIANN products (10 -13 %.). Non-gauge adjusted

  20. A White Nile megalake during the last interglacial period

    NASA Astrophysics Data System (ADS)

    Barrows, Timothy T.; Williams, Martin A. J.; Mills, Stephanie C.; Duller, Geoff A. T.; Fifield, L. Keith; Haberlah, David; Tims, Stephen G.; Williams, Frances M.

    2014-05-01

    The eastern Sahara Desert of Africa is one of the most climatically sensitive areas on Earth, varying from lake-studded savannah woodland to hyperarid desert over the course of a glacial-interglacial cycle. In currently semiarid Sudan there is widespread evidence that a very large freshwater lake once filled the White Nile River valley (Barrows et al., 2014). Here we present the first quantitative estimate for the dimensions of the lake and a direct age for the emplacement of its shoreline. Using a profile dating approach with the cosmogenic nuclide 10Be, we estimate an exposure age of 109 ± 8 ka for this megalake, indicating that it probably formed during the last interglacial period. This age is supported by optically stimulated luminescence dating of Blue Nile paleochannels associated with the lake. Using a high-resolution digital elevation model, we estimate that the lake was more than 45,000 km2 in area, making it comparable to the largest freshwater lakes on Earth today. We attribute the lake's existence to seasonal flood pulses as a result of local damming of the White Nile by a more southern position of the Blue Nile and greatly increased precipitation associated with an enhanced monsoon. References Barrows, T.T., Williams, M.A.J., Mills, S.C., Duller, G.A.T., Fifield, L.K., Haberlah, D., Tims, S.G., Williams, F.M., 2014. A White Nile megalake during the last interglacial period. Geology. 10.1130/g35238.1

  1. Analysis of stream-aquifer system interrelationships in the Big Blue and Little Blue River basins in Gage and Jefferson Counties, Nebraska

    USGS Publications Warehouse

    Ellis, M.J.

    1981-01-01

    Seepage measurements made during the fall of 1978 at 21 sites in the Big Blue River basin and at 35 sites in the Little Blue River basin were used to determine stream gains or losses in 20 drainage areas in the Big Blue River basin and 31 drainage areas in the Little Blue River basin. Analyses of data from these seepage measurements and of available hydrogeologic data indicate that the most significant ground-water contributions to streamflow in the Big Blue and Little Blue River drainage basins in Gage and Jefferson Counties, Nebr., occur where a direct hydraulic connection exists between a stream and buried coarse-grained deposits of Quaternary age. These deposits occur in two buried bedrock valleys that trend east-northeasterly across the area. The largest ground-water contributions to streamflow in the Big Blue River occur in the reaches of the river between the mouth of Mud Creek and the dam at Blue Springs (about 13 cubic feet per second) and between the mouth of Turkey Creek and the Beatrice gaging station (about 22 cubic feet per second). Ground-water contributions to streamflow also occur in two tributaries of the Big Blue River; Bear Creek (4.39 cubic feet per second) and Big Indian Creek (6.23 cubic feet per second). In the Little Blue River basin the largest contributions to streamflow occur between the mouths of Big Sandy Creeks (about 6.5 cubic feet per second) and in the vicinity of Fairbury (about 16 cubic feet per second). A ground-water contribution to streamflow of about 6.5 cubic feet per second also occurs in Rose Creek, a tributary of the Little Blue River. (USGS)

  2. West Nile virus epizootiology, central Red River Valley, North Dakota and Minnesota, 2002-2005.

    PubMed

    Bell, Jeffrey A; Brewer, Christina M; Mickelson, Nathan J; Garman, Gabriel W; Vaughan, Jefferson A

    2006-08-01

    West Nile virus (WNV) epizootiology was monitored from 2002 through 2005 in the area surrounding Grand Forks, North Dakota. Mosquitoes were tested for infection, and birds were surveyed for antibodies. In 2003, WNV was epidemic; in 2004, cool temperatures precluded WNV amplification; and in 2005, immunity in passerines decreased, but did not preclude, WNV amplification.

  3. West Nile Virus Epizootiology, Central Red River Valley, North Dakota and Minnesota, 2002–2005

    PubMed Central

    Bell, Jeffrey A.; Brewer, Christina M.; Mickelson, Nathan J.; Garman, Gabriel W.

    2006-01-01

    West Nile virus (WNV) epizootiology was monitored from 2002 through 2005 in the area surrounding Grand Forks, North Dakota. Mosquitoes were tested for infection, and birds were surveyed for antibodies. In 2003, WNV was epidemic; in 2004, cool temperatures precluded WNV amplification; and in 2005, immunity in passerines decreased, but did not preclude, WNV amplification. PMID:16965705

  4. Holocene evolution of the River Nile drainage system as revealed from the Lake Dendi sediment record, central Ethiopian highlands

    NASA Astrophysics Data System (ADS)

    Wagner, B.; Viehberg, F. A.; Wennrich, V.; Junginger, A.; Kolvenbach, A.; Rethemeyer, J.; Schaebitz, F.; Schmiedl, G. H.

    2015-12-01

    A 12 m long sediment sequence from Dendi Crater lakes, located on the central Ethiopian Plateau, was analysed with sedimentological and geochemical methods to reconstruct the regional environmental history. Bulk organic carbon samples from 23 horizons throughout the sequence were used for AMS radiocarbon dating and indicate that the sediment sequence spans the last ca. 12 cal kyr BP. Microscope analyses and sedimentological data reveal three tephra layers, of which the most prominent layer with a thickness of ~2 m was deposited at 10.2 cal kyr BP and probably originates from an eruption of the Wenchi crater 12 km to the west of the Dendi lakes. Sedimentological data of the pelagic deposits indicate shifts in erosion and rainfall throughout the record. A decrease in Ca and Sr at 11.6 cal kyr BP is related to the shift of less humid condition during the Younger Dryas (YD) to the return to full humid conditions of the African Humid Period (AHP). Single thin horizons with high carbonate content or high Ti and K imply that short spells of dry conditions and significantly increased rainfall superimpose the generally more humid conditions during the AHP. The end of the AHP is gradual. Relatively stable and less humid conditions characterised the Dendi Crater lakes until around 3.9 cal kyr BP. A highly variable increase in clastic matter over the last 1500 years indicates higher erosion due to short-term variations in precipitation within the Dendi catchment. Overall, the sediment record suggests moderate change of precipitation during the Holocene, which is probably due to their exposed location in the Ethiopian highlands. The data from the Dendi Crater lakes show, in concert with other records from the Nile catchment and the Eastern Mediterranean Sea (EMS), that the Blue Nile provided the main freshwater source for maintaining EMS stratification and sapropel S1 formation between ca. 10.0 and 8.7 cal kyr BP. Subsequent aridification is recorded from equatorial East Africa

  5. Spectrophotometric reaction rate method for the determination of trace amounts of vanadium(V) by its catalytic effect on the oxidation of Nile blue with bromate

    SciTech Connect

    Ensafi, A.A.; Amini, M.K.; Mazloum, M.

    1999-07-01

    A kinetic spectrophotometric method for the determination of trace amounts of vanadium(V) is described. It is based on the catalytic action of this ion on the oxidation of Nile blue by bromate, which yields a colorless product in acidic media. The reaction is followed spectrophotometrically by measuring the rate of decrease in absorbance at 585 nm and 30 C. A fixed time method of 4.0 min from initiation of the reaction was used. Vanadium(V) in the range of 0.004--0.520 {micro}g/ml can be determined. The proposed method is hardly subject to interference. The parameters affecting the sensitivity were optimized. The proposed method was used for the determination of vanadium in water and in milk samples.

  6. Evaluation of ozone for preventing fungal influenced corrosion of reinforced concrete bridges over the River Nile, Egypt.

    PubMed

    Geweely, Neveen S I

    2011-04-01

    Fungal influenced corrosion (FIC) of some corroded sites in three selected bridges [Embaba bridge (E-bridge), Kasr al-Nile-bridge (K-bridge) and University bridge (U-bridge)] located over the River Nile in Egypt were investigated. Six fungal species, belong to 12 fungal genera, were isolated from the corroded reinforced concrete of the three tested bridges. Fourier transform infrared spectroscopy (FTIR) was screened for the most dominant fungal species (Fusarium oxysporium) which showed in all tested bridges that indicated the presence of amine group accompanied with polysaccharides contents. FIC of the most deteriorated bridge (K-bridge) was documented with FTIR. The association of fungal spores with corrosion products was recorded with scanning electron microscope (SEM). Evaluation of ozone for preventing FIC of the K-bridge was carried out by recording the corrosion rate and the corresponding inhibition efficiency (IE%). No mycelial growth with 100% IE was observed at 3 ppm ozone concentration after 120 min exposure time. With longer duration of ozone exposure, the membrane permeability of F. oxysporium was compromised as indicated by protein and nucleic acid leakages accompanied with lipid and tryptophan oxidation. The total intracellular and extracellular proteins of F. oxysporium were run on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) indicated the increasing of the supernatant protein on the expense of the cellular protein bands with extending ozone exposure time (0-80 min).

  7. Characterisation of stable isotopes to identify residence times and runoff components in two meso-scale catchments in the Abay/Upper Blue Nile basin, Ethiopia

    NASA Astrophysics Data System (ADS)

    Tekleab, S.; Wenninger, J.; Uhlenbrook, S.

    2014-06-01

    Measurements of the stable isotopes oxygen-18 (18O) and deuterium (2H) were carried out in two meso-scale catchments, Chemoga (358 km2) and Jedeb (296 km2) south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin, as more than 70% of total Nile water flow originates from the Ethiopian highlands. Stable isotope compositions in precipitation, spring water and streamflow were analysed (i) to characterise the spatial and temporal variations of water fluxes; (ii) to estimate the mean residence time of water using a sine wave regression approach; and (iii) to identify runoff components using classical two-component hydrograph separations on a seasonal timescale. The results show that the isotopic composition of precipitation exhibits marked seasonal variations, which suggests different sources of moisture generation for the rainfall in the study area. The Atlantic-Indian Ocean, Congo basin, Upper White Nile and the Sudd swamps are the potential moisture source areas during the main rainy (summer) season, while the Indian-Arabian and Mediterranean Sea moisture source areas during little rain (spring) and dry (winter) seasons. The spatial variation in the isotopic composition is influenced by the amount effect as depicted by moderate coefficients of determination on a monthly timescale (R2 varies from 0.38 to 0.68) and weak regression coefficients (R2 varies from 0.18 to 0.58) for the altitude and temperature effects. A mean altitude effect accounting for -0.12‰/100 m for 18O and -0.58‰/100 m for 2H was discernible in precipitation isotope composition. Results from the hydrograph separation on a seasonal timescale indicate the dominance of event water, with an average of 71 and 64% of the total runoff during the wet season in the Chemoga and Jedeb catchments, respectively. Moreover, the stable isotope compositions of streamflow samples were damped compared to the input function of

  8. Nesting ecology and nest success of the Blue Grosbeak along two rivers in New Mexico

    Treesearch

    Jean-Luc E. Cartron; Deborah M. Finch; David L. Hawksworth; Scott H. Stoleson

    2013-01-01

    From 1997 through 2008, we studied the nesting habits and nest success of the Blue Grosbeak (Passerina cerulean) along the middle Gila River (1997-2001) and the middle Rio Grande (2000-2008) in New Mexico. A riparian forest of cottonwoods grows along both rivers. but the forest along the Rio Grande is a much more intensively managed ecosystem, with an understory...

  9. Analysis of water quality in the Blue River watershed, Colorado, 1984 through 2007

    USGS Publications Warehouse

    Bauch, Nancy J.; Miller, Lisa D.; Yacob, Sharon

    2014-01-01

    Water quality of streams, reservoirs, and groundwater in the Blue River watershed in the central Rocky Mountains of Colorado has been affected by local geologic conditions, historical hard-rock metal mining, and recent urban development. With these considerations, the U.S. Geological Survey, in cooperation with the Summit Water Quality Committee, conducted a study to compile historical water-quality data and assess water-quality conditions in the watershed. To assess water-quality conditions, stream data were primarily analyzed from October 1995 through December 2006, groundwater data from May 1996 through September 2004, and reservoir data from May 1984 through November 2007. Stream data for the Snake River, upper Blue River, and Tenmile Creek subwatersheds upstream from Dillon Reservoir and the lower Blue River watershed downstream from Dillon Reservoir were analyzed separately. (The complete abstract is provided in the report)

  10. LIS-HYMAP coupled Hydrological Modeling in the Nile River Basin and the Greater Horn of Africa

    NASA Astrophysics Data System (ADS)

    Jung, H. C.; Getirana, A.; Policelli, F. S.

    2015-12-01

    Water scarcity and resources in Africa have been exacerbated by periodic droughts and floods. However, few studies show the quantitative analysis of water balance or basin-scale hydrological modeling in Northeast Africa. The NASA Land Information System (LIS) is implemented to simulate land surface processes in the Nile River Basin and the Greater Horn of Africa. In this context, the Noah land surface model (LSM) and the Hydrological Modeling and Analysis Platform (HYMAP) are used to reproduce the water budget and surface water (rivers and floodplains) dynamics in that region. The Global Data Assimilation System (GDAS) meteorological dataset is used to force the system . Due to the unavailability of recent ground-based observations, satellite data are considered to evaluate first model outputs. Water levels at 10 Envisat virtual stations and water discharges at a gauging station are used to provide model performance coefficients (e.g. Nash-Sutcliffe, delay index, relative error). We also compare the spatial and temporal variations of flooded areas from the model with the Global Inundation Extent from Multi-Satellites (GIEMS) and the Alaska Satellite Facility (ASF)'s MEaSUREs Wetland data. Finally, we estimate surface water storage variations using a hypsographic curve approach with Shuttle Radar Topography Mission (SRTM) topographic data and evaluate the model-derived water storage changes in both river and floodplain. This study demonstrates the feasibility of using LIS-HYMAP coupled modeling to support seasonal forecast methods for prediction of decision-relevant metrics of hydrologic extremes.

  11. Coupled hydrologic and land use change models for decision making on land and water resources in the Upper Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Yalew, Seleshi; van der Zaag, Pieter; Mul, Marloes; Uhlenbrook, Stefan; Teferi, Ermias; van Griensven, Ann; van der Kwast, Johannes

    2013-04-01

    Hydrology of a basin, alongside climate change, is well documented to impact and to be impacted by land use/land cover change processes. The need to understand the impacts of hydrology on land use change and vice- versa cannot be overstated especially in basins such as the Upper Blue Nile in Ethiopia, where the vast majority of farmers depend on rain-fed agriculture. A slight fluctuation in rainy seasons or an increase or decrease in magnitude of precipitation can easily trigger drought or flooding. On the other hand, ever growing population and emerging economic development, among others, is likely to continually alter land use/land cover change, thereby affecting hydrological processes. With the intention of identifying and analyzing interactions and future scenarios of the hydrology and land use/land cover, we carried out a case study on a meso-scale catchment, in the Upper Blue Nile basin. A land use model using SITE (SImulation of Terrestrial Environments) was built for analyzing land use trends from aerial land cover photographs of 1957 and simulate until 2009 based on socio-economic as well as biophysical factors. Major land use drivers in the catchment were identified and used as input to the land use model. Separate land use maps were produced using Landsat images of 1972, 1986, 1994 and 2009 for historical calibration of the land use model. By the same token, a hydrological model for the same catchment was built using the SWAT (Soil and Water Assessment Tool) model. After calibration of the two independent models, they were loosely coupled for analyzing the changes in either of the models and impacts on the other. Among other details, the coupled model performed better in identifying limiting factors from both the hydrology as well as from the land use perspectives. For instance, the simulation of the uncoupled land use model alone (without inputs from SWAT on the water budget of each land use parcel) continually considered a land use type such as a wet

  12. Summer Rains and Dry Seasons in the Upper Blue Nile Basin: The Predictability of Half a Century of Past and Future Spatiotemporal Patterns

    PubMed Central

    Mellander, Per-Erik; Gebrehiwot, Solomon G.; Gärdenäs, Annemieke I.; Bewket, Woldeamlak; Bishop, Kevin

    2013-01-01

    During the last 100 years the Ethiopian upper Blue Nile Basin (BNB) has undergone major changes in land use, and is now potentially facing changes in climate. Rainfall over BNB supplies over two-thirds of the water to the Nile and supports a large local population living mainly on subsistence agriculture. Regional food security is sensitive to both the amount and timing of rain and is already an important political challenge that will be further complicated if scenarios of climate change are realized. In this study a simple spatial model of the timing and duration of summer rains (Kiremt) and dry season (Bega), and annual rain over the upper BNB was established from observed data between 1952 and 2004. The model was used to explore potential impacts of climate change on these rains, using a down-scaled ECHAM5/MP1-OM scenario between 2050 and 2100. Over the observed period the amount, onset and duration of Kiremt rains and rain-free Bega days have exhibited a consistent spatial pattern. The spatially averaged annual rainfall was 1490 mm of which 93% was Kiremt rain. The average Kiremt rain and number of rainy days was higher in the southwest (322 days) and decreased towards the north (136 days). Under the 2050–2100 scenario, the annual mean rainfall is predicted to increase by 6% and maintain the same spatial pattern as in the past. A larger change in annual rainfall is expected in the southwest (ca. +130 mm) with a gradually smaller change towards the north (ca. +70 mm). Results highlight the need to account for the characteristic spatiotemporal zonation when planning water management and climate adaptation within the upper BNB. The presented simple spatial resolved models of the presence of Kiremt and annual total rainfall could be used as a baseline for such long-term planning. PMID:23869219

  13. Nile behaviour and Late Palaeolithic humans in Upper Egypt during the Late Pleistocene

    NASA Astrophysics Data System (ADS)

    Vermeersch, Pierre M.; Van Neer, Wim

    2015-12-01

    The reconstruction of the environment and the human population history of the Nile Valley during the Late Pleistocene have received a lot of attention in the literature thus far. There seems to be a consensus that during MIS2 extreme dry conditions prevailed over north-eastern Africa, which was apparently not occupied by humans. The Nile Valley seems to be an exception; numerous field data have been collected suggesting an important population density in Upper Egypt during MIS2. The occupation remains are often stratified in, or at least related to, aeolian and Nile deposits at some elevation above the present-day floodplain. They are rich in lithics and animal bones, mainly fish, illustrating the exploitation of the Nile Valley by the Late Palaeolithic inhabitants. The fluvial processes active during that period have traditionally been interpreted as a continuously rising highly braided river. In this paper we summarize the evidence thus far available for the Late Pleistocene on the population densities in the Nile Valley, and on the models of Nilotic behaviour. In the discussion we include data on the environmental conditions in Eastern Africa, on the aeolian processes in the Western Desert of Egypt derived from satellite images, 14C and OSL dates, in order to formulate a new model that explains the observed high remnants of aeolian and Nilotic deposits and the related Late Palaeolithic sites. This model hypothesizes that, during the Late Pleistocene, and especially the LGM, dunes from the Western Desert invaded the Nile Valley at several places in Upper Egypt. The much reduced activity of the White Nile and the Blue Nile was unable to evacuate incoming aeolian sand and, as a consequence, several dams were created in the Upper Egyptian Nile Valley. Behind such dams the created lakes offered ideal conditions for human subsistence. This model explains the occurrence of Late Palaeolithic hunter-fisher-gatherers in a very arid environment with very low Nile flows

  14. Identification of the main attribute of river flow temporal variations in the Nile Basin

    NASA Astrophysics Data System (ADS)

    Onyutha, C.; Willems, P.

    2015-11-01

    Temporal variation of monthly flows was investigated at 18 Discharge Measurement Stations (DMS) within the Nile Basin in Africa. The DMS were grouped using a clustering procedure based on the similarity in the flow variation patterns. The co-variation of the rainfall and flow was assessed in each group. To investigate the possible change in catchment behavior, which may interfere with the flow-rainfall relationship, three rainfall-runoff models were applied to the major catchment in each group based on the data time period falling within 1940-2003. The co-occurrence of the changes in the observed and simulated overland flow was examined using the cumulative rank difference (CRD) technique and the quantile perturbation method (QPM). Two groups of the DMS were obtained. Group 1 comprises the DMS from the equatorial region and/or South Sudan, while those in Sudan, Ethiopia and Egypt form group 2. In the selected catchment of each group, the patterns of changes in terms of the CRD sub-trends and QPM anomalies for both the observed and simulated flows were in a close agreement. These results indicate that change in catchment behavior due to anthropogenic influence in the Nile basin over the selected time period was minimal. Thus, the overall rainfall-runoff generation processes of the catchments were not impacted upon in a significant way. The temporal flow variations could be attributed mainly to the rainfall variations.

  15. Nile Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Nile Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population of 57 million. The capital city of Cairo is at the apex of the delta in the middle of the scene. Across the river from Cairo can be seen the three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  16. Water resources of the Blue Earth River watershed, south-central Minnesota

    USGS Publications Warehouse

    Anderson, H.W.; Farrell, D.F.; Broussard, W.L.

    1974-01-01

    The Blue Earth River Watershed in Minnesota includes 3,106 square miles of land surface, which varies from fairly flat to gently rolling. The drainage extends south to include an additional 450 square miles in Iowa. The western, southern, and eastern boundaries are end moraines formed by Pleistocene glaciers. Major streams have eroded channels 40 to 75 feet deep in headwater regions and 150 to 200 feet deep near the mouth of the Blue Earth River at Mankato. In their lower reaches major streams have cut through glacial deposits and into underlying bedrock (described on ground-water sheet).

  17. The Carbon Cycle at the Nile Headwaters

    NASA Astrophysics Data System (ADS)

    Jones, Michael; Saunders, Matthew

    2014-05-01

    The carbon cycle at the Nile headwaters M B Jones, School of Natural Sciences, Trinity College, University of Dublin, Dublin 2, Ireland M Saunders, Environmental and Biochemical Sciences Group, The James Hutton Institute, Aberdeen, Scotland River systems play an integral role in the global carbon cycle by connecting the terrestrial biosphere, the atmosphere and the oceans. Extensive wetland systems, such as those found in the Amazon region, have been shown to export significant amounts of carbon to river waters as dissolved carbon dioxide (CO2) that can be transported and emitted hundreds of km downstream. The assessment of both regional and global carbon budgets could therefore be improved by quantifying these lateral carbon fluxes, especially from highly productive temporarily or permanently flooded areas where substantial CO2 evasion from inland waters can occur. The Nile is the longest river in the world and the headwaters are located in the extensive Papyrus dominated wetlands in central Africa that are associated with Lake Victoria. From its source the White Nile flows northwards through wetlands in Uganda and Sudan before it joins the Blue Nile. Papyrus wetlands have been shown to be some of the most productive global ecosystems, with recorded rates of aerial net primary productivity of up to 3.09 kg C m-2 yr-1. In addition, where anaerobic conditions occur they also accumulate large amounts of carbon in the form of peat, and under these circumstances they represent a significant carbon sink. However, as water moves through these wetlands and is exchanged with surrounding rivers and lakes significant quantities of dissolved organic and inorganic carbon as well as suspended particulate organic matter are exported, which are either released further downstream by degassing, decomposition or deposition. Information on such losses from these wetland ecosystems is extremely sparse but in order to better constrain ecosystem scale carbon dynamics more accurate

  18. The Nile Delta, Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This pair of true- and false-color images from the Moderate Resolution Imaging Spectroradiometer was acquired on June 3, 2002. The fertile land along the Nile River supports lush green vegetation, amid the desert landscape. At its delta at the Mediterranean Sea, the Nile broadens into a large fan-shaped delta. All of Egypt's large cities fall along the Nile, which sustains life in a region of scant rainfall. At the point where the river widens into the delta, a grayish cluster of pixels marks the location of Cairo. To the east is the Sinai Peninsula, whose impermanent water courses create silvery streaks on the pale brown, arid landscape. At lower right is the Red Sea. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  19. Diet and population metrics of the introduced blue catfish population in the Altamaha, River, GA

    USGS Publications Warehouse

    Bonvechio, Timothy F.; Jennings, Cecil A.

    2011-01-01

    Blue catfish (Ictalurus furcatus) were first detected in the Altamaha River, Georgia, during an access creel survey in 2005 and subsequently in 2006 during annual ictalurid sampling. Introduction of this species in the Altamaha River is believed to have occurred via escape from normal upstream reservoir releases from Lake Sinclair and Lake Oconee. Relative abundance, as indexed by electrofishing catch rate (fish per hour), has increased from 2.9±1.0 SE in 2006 to 38.8±8.2 SE in 2011. The size of blue catfish captured ranged from 56 to 820 mm total length and 0.001 to 7.7 kg. Using otoliths obtained in 2010 (n=214), age of fish ranged from 0 to 6 yrs, which indicated a relatively young population. The catch-curve analysis resulted in an instantaneous mortality rate (Z) of 0.75. Despite concerns of blue catfish predation on native fishes and mussels, a diet analysis of blue catfish (n=257) obtained in 2010 revealed that diets of fish in all size groups were dominated by the introduced Asiatic clam (Corbicula fluminea). This study describes a recently introduced blue catfish population in an Atlantic coastal plain river and provides insight on possible ecological effects during the early phases of establishment. These results offer an early status assessment of the invasion dynamics before the system has had time to reach a new equilibrium state.

  20. Simple and Rapid Differentiation of Mycobacterium tuberculosis H37Ra from M. tuberculosis Clinical Isolates through Two Cytochemical Tests Using Neutral Red and Nile Blue Stains

    PubMed Central

    Soto, Carlos Y.; Andreu, Núria; Gibert, Isidre; Luquin, Marina

    2002-01-01

    The attenuated Mycobacterium tuberculosis strain H37Ra is one of the most commonly used controls for M. tuberculosis identification in the clinical laboratory and is a source of false-positive results for M. tuberculosis as a consequence of cross-contamination. Therefore, the ability to discriminate between H37Ra and real clinical isolates has important public health implications. To date, differentiation of H37Ra from M. tuberculosis clinical isolates is possible only by IS6110 genotyping and spoligotyping. In the 1950s, some authors reported that the virulent strain H37Rv and M. tuberculosis clinical isolates were able to fix basic dyes in their anionic forms, while H37Ra was not. We have studied the different techniques described for M. tuberculosis cytochemical staining and have chosen the best of these, introducing certain modifications in order to increase their discriminative power and reproducibility. We describe cytochemical staining of M. tuberculosis cells with neutral red and Nile blue, which differentiates H37Ra from virulent strains. This method could be used as an easy laboratory tool for distinguishing between H37Ra and real M. tuberculosis clinical isolates. PMID:12149369

  1. Simple and rapid differentiation of Mycobacterium tuberculosis H37Ra from M. tuberculosis clinical isolates through two cytochemical tests using neutral red and nile blue stains.

    PubMed

    Soto, Carlos Y; Andreu, Núria; Gibert, Isidre; Luquin, Marina

    2002-08-01

    The attenuated Mycobacterium tuberculosis strain H37Ra is one of the most commonly used controls for M. tuberculosis identification in the clinical laboratory and is a source of false-positive results for M. tuberculosis as a consequence of cross-contamination. Therefore, the ability to discriminate between H37Ra and real clinical isolates has important public health implications. To date, differentiation of H37Ra from M. tuberculosis clinical isolates is possible only by IS6110 genotyping and spoligotyping. In the 1950s, some authors reported that the virulent strain H37Rv and M. tuberculosis clinical isolates were able to fix basic dyes in their anionic forms, while H37Ra was not. We have studied the different techniques described for M. tuberculosis cytochemical staining and have chosen the best of these, introducing certain modifications in order to increase their discriminative power and reproducibility. We describe cytochemical staining of M. tuberculosis cells with neutral red and Nile blue, which differentiates H37Ra from virulent strains. This method could be used as an easy laboratory tool for distinguishing between H37Ra and real M. tuberculosis clinical isolates.

  2. Water and Regional Stability: The Nile a Case Study

    DTIC Science & Technology

    2011-03-24

    of the Nile River basin include the Hydromet Survey (1967-1992) and Technical Cooperation Committee for the Promotion of the Development and...Environmental Protection of the Nile Basin (TECCONILE) (1992-1998) The Hydromet Survey was a mechanism for Riparians along the Nile River to receive

  3. 76 FR 25545 - Safety Zone; Blue Crab Festival Fireworks Display, Little River, Little River, SC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-05

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Blue Crab Festival Fireworks Display... Carolina during the Blue Crab Festival Fireworks Display on Friday, ] May 13, 2011. The safety zone is... this rule because the Coast Guard did not receive notice of the Blue Crab Festival Fireworks...

  4. Ocean-color remote sensing of the Nile delta shelf and SE Levantine basin and possible linkage to some mesoscale circulation features and Nile river run-off

    NASA Astrophysics Data System (ADS)

    Moufaddal, Wahid; Lavender, Samantha

    To date, and despite the passage of more than 30 years since the launch of the first satellite based ocean-color sensor, no systematic study of the variability of chlorophyll in the Egyptian Mediterranean coast off the Nile delta has been undertaken using this kind of data. Meantime, available in-situ measurements on chlorophyll and other nutrient parameters along this coast are indeed very modest and scarce. The lack of data has in turn created a large gap in our knowledge on the biogeochemical characteristics of the coastal water and impacts of the Aswan High Dam and other land-use changes on the marine ecosystems and nutrient budget in the Nile delta shelf and the SE Mediterranean. The present study aims to fill part of this gap through application of ocean-color remote sensing and satellite retrieval of phytoplankton chlorophyll. For this purpose a 10-year (1997-2006) monthly satellite dataset from ESA Globcolour project (an ESA Data User Element project: http://www.globcolour.info) was retrieved and subjected to time-series analysis. Results of this analysis revealed that the oceanic and coastal parts off the Nile delta coast and SE Mediterranean manifest from time to time some of the most interesting and dynamical marine features including meso-scale gyres, coastal filaments, localized algal blooms and higher concentration of phytoplankton chlorophyll. These features together with certain physical pro-cesses and surface run-off from Nile mouthes and other land-based sources were found to exert pronounced effects on the nutrient supply and quality of the coastal and oceanic surface waters in this region. Results reveled also that there has been a general upward trend in concentration of surface chlorophyll during the 10-year period from 1997 to 2006 with a coincident rise of the coastal fisheries implying that improvement of nutrient supply is most likely responsible for this rise. Results confirmed also shift of the Nile phytoplankton bloom in space and time

  5. Natural radioactivity levels and associated health hazards from the terrestrial ecosystem in Rosetta branch of the River Nile, Egypt.

    PubMed

    Abdellah, W M; Diab, H M; El-Kameesy, S U; Salama, E; El-Framawy, S

    2017-08-01

    Twenty soil and 25 sediment samples were collected from the banks and bottom of the River Nile in the surroundings of biggest cities located close to it. Natural radioactivity concentrations of (226)Ra, (232)Th and (40)K have been evaluated for all samples by means of γ spectrometric analysis. The radioactivity levels of soil and sediment samples fall within the internationally recommended values. Nevertheless, high natural background radiation zones are detected in the Kafr El-Zayat region due to the presence of a fertilizer factory, and in the Rosetta region due to the presence of black sand deposits. The absorbed dose rate, the γ index and excess life time cancer risk are calculated. High values for some of the radiation health parameters are detected in the Kafr El-Zayat and Rosetta regions representing a serious problem to public health because the soil and sediment are used as constructing material for buildings. Furthermore, the isotope analysis of uranium for representative collected sediment samples via α spectrometry showed average specific activities of 18.7 ± 3.6, 0.087 ± 0.0038 and 18.6 ± 3.8 Bq kg(-1) for (234)U, (235)U and (238)U, respectively. In general, these values confirm the balance in the isotopic abundance of U isotopes.

  6. Clinical Report: Schistosomiasis Exposure in U.S. Service Personnel During Whitewater Rafting on the Nile River in Jinja, Uganda.

    PubMed

    Maluil, Samuel; Stevens, Rom A

    2016-11-01

    Schistosomiasis is a known risk after exposure to freshwater in tropical parts of the world. In March 2014, 28 off-duty U.S. service members went on a water adventure in the Nile River in Jinja, Uganda. In April 2014, 10 of the 28 service members returned for a second water adventure. Twelve weeks after freshwater exposure, schistosomiasis enzyme-linked immunosorbent assay testing was performed. Twenty-five percent had elevated Schistosomiasis mansoni immunoglobulin G (7 positive of 28 exposed); all had negative pre-exposure serology. The serology-positive service members were treated with oral praziquantel 60 mg/kg in divided doses. Our report is the first schistosomiasis report among U.S. service members deployed to Africa since World War II. The absence of reports among U.S. service members and several reports among deployed foreign military units and tourists in sub-Saharan Africa suggest a lack of postexposure testing. We recommend schistosomiasis testing of prior and future U.S. military units deployed to sub-Saharan Africa with fresh water exposure. Unit commanders and medical personnel should discourage unnecessary fresh water contact in sub-Saharan Africa.

  7. Quantification of River Nile/Quaternary aquifer exchanges via riverbank filtration by hydrochemical and biological indicators, Assiut, Egypt

    NASA Astrophysics Data System (ADS)

    Abdalla, Fathy; Shamrukh, Mohamed

    2016-12-01

    This study approach seeks to characterize the hydraulic interactions between the Nile and the Quaternary aquifer via riverbank filtration (RBF) in Abu Tieg area, Assuit Governorate. The substantial removal/reduction of the most problematic substances during percolation of Nile water into abstraction wells was investigated using physico-chemical and biological indicators. Four sites with 11 municipal wells (20-750 m from the Nile) tapping the alluvial aquifer that is fed by the riverbank infiltrate were monitored. Bank-filtrated water was compared with those of the Nile and groundwater. Results showed that infiltrated Nile water ratio into the wells ranged from 39 to 80% reflecting the effect of distance from the Nile. Removal efficiency of total algal, total and faecal coliforms in bank-filtered water was 99.9%, while turbidity removal ranged from 93 to 98%. Fe, Mn and Zn in the bank-filtered water were relatively higher than those in the Nile, but were still under the allowable standards except those of Mn. LSI and WQI for the bank-filtered water indicated that the water was ranked as non-corrosive and of excellent quality. Comparison of physico-chemical and microbiological characteristics of the bank-filtered water with those of the Nile and groundwater showed the high efficiency of RBF as a treatment technology with minimal cost compared to conventional methods.

  8. Mosquitoes and West Nile virus along a river corridor from prairie to montane habitats in eastern Colorado.

    PubMed

    Barker, Christopher M; Bolling, Bethany G; Black, William C; Moore, Chester G; Eisen, Lars

    2009-12-01

    We conducted studies on mosquitoes and West Nile virus (WNV) along a riparian corridor following the South Platte River and Big Thompson River in northeastern Colorado and extending from an elevation of 1,215 m in the prairie landscape of the eastern Colorado plains to 1,840 m in low montane areas at the eastern edge of the Rocky Mountains in the central part of the state. Mosquito collection during June-September 2007 in 20 sites along this riparian corridor yielded a total of 199,833 identifiable mosquitoes of 17 species. The most commonly collected mosquitoes were, in descending order: Aedes vexans, Culex tarsalis, Ae. dorsalis, Ae. trivittatus, Ae. melanimon, Cx. pipiens, and Culiseta inornata. Species richness was higher in the plains than in foothills-montane areas, and abundances of several individual species, including the WNV vectors Cx. tarsalis and Cx. pipiens and the nuisance-biter and potential secondary WNV vector Ae. vexans, decreased dramatically from the plains (1,215-1,487 m) to foothills-montane areas (1,524-1,840 m). Ae. vexans and Cx. tarsalis had a striking pattern of uniformly high abundances between 1,200-1,450 m followed by a gradual decrease in abundance above 1,450 m to reach very low numbers above 1,550 m. Culex species were commonly infected with WNV in the plains portion of the riparian corridor in 2007, with 14 of 16 sites yielding WNV-infected Cx. tarsalis and infection rates for Cx. tarsalis females exceeding 2.0 per 1,000 individuals in ten of the sites. The Vector Index for abundance of WNV-infected Cx. tarsalis females during June-September exceeded 0.5 in six plains sites along the South Platte River but was uniformly low (0-0.1) in plains, foothills and montane sites above 1,500 m along the Big Thompson River. A population genetic analysis of Cx. tarsalis revealed that all collections from the ≈190 km riparian transect in northeastern Colorado were genetically uniform but that these collections were genetically distinct from

  9. Biophysical and financial impacts of community-based gully rehabilitation in the Birr Watershed, Upper Blue Nile Basin, Ethiopia

    USDA-ARS?s Scientific Manuscript database

    Although erosion in the Ethiopian highlands has been occurring for thousands of years, rivers sediment concentration has increased two to three fold during the last fifty years, reducing crop and livestock production and the volume of irrigation water stored in reservoirs. Gully erosion in particula...

  10. Understanding the Ecology of Blue Elderberry to Inform Landscape Restoration in Semiarid River Corridors

    NASA Astrophysics Data System (ADS)

    Vaghti, Mehrey G.; Holyoak, Marcel; Williams, Amy; Talley, Theresa S.; Fremier, Alexander K.; Greco, Steven E.

    2009-01-01

    Societal constraints often limit full process restoration in large river systems, making local rehabilitation activities valuable for regeneration of riparian vegetation. A target of much mitigation and restoration is the federally threatened Valley elderberry longhorn beetle and its sole host plant, blue elderberry, in upper riparian floodplain environments. However, blue elderberry ecology is not well understood and restoration attempts typically have low success rates. We determined broad-scale habitat characteristics of elderberry in altered systems and examined associated plant species composition in remnant habitat. We quantified vegetation community composition in 139 remnant riparian forest patches along the Sacramento River and elderberry stem diameters along this and four adjacent rivers. The greatest proportion of plots containing elderberry was located on higher and older floodplain surfaces and in riparian woodlands dominated by black walnut. Blue elderberry saplings and shrubs with stems <5.0 cm in diameter were rare, suggesting a lack of recruitment. A complex suite of vegetation was associated with blue elderberry, including several invasive species which are potentially outcompeting seedlings for light, water, or other resources. Such lack of recruitment places increased importance on horticultural restoration for the survival of an imperiled species. These findings further indicate a need to ascertain whether intervention is necessary to maintain functional and diverse riparian woodlands, and a need to monitor vegetative species composition over time, especially in relation to flow regulation.

  11. Understanding the ecology of blue elderberry to inform landscape restoration in semiarid river corridors.

    PubMed

    Vaghti, Mehrey G; Holyoak, Marcel; Williams, Amy; Talley, Theresa S; Fremier, Alexander K; Greco, Steven E

    2009-01-01

    Societal constraints often limit full process restoration in large river systems, making local rehabilitation activities valuable for regeneration of riparian vegetation. A target of much mitigation and restoration is the federally threatened Valley elderberry longhorn beetle and its sole host plant, blue elderberry, in upper riparian floodplain environments. However, blue elderberry ecology is not well understood and restoration attempts typically have low success rates. We determined broad-scale habitat characteristics of elderberry in altered systems and examined associated plant species composition in remnant habitat. We quantified vegetation community composition in 139 remnant riparian forest patches along the Sacramento River and elderberry stem diameters along this and four adjacent rivers. The greatest proportion of plots containing elderberry was located on higher and older floodplain surfaces and in riparian woodlands dominated by black walnut. Blue elderberry saplings and shrubs with stems <5.0 cm in diameter were rare, suggesting a lack of recruitment. A complex suite of vegetation was associated with blue elderberry, including several invasive species which are potentially outcompeting seedlings for light, water, or other resources. Such lack of recruitment places increased importance on horticultural restoration for the survival of an imperiled species. These findings further indicate a need to ascertain whether intervention is necessary to maintain functional and diverse riparian woodlands, and a need to monitor vegetative species composition over time, especially in relation to flow regulation.

  12. Simulation of blue and green water resources in the Wei River basin, China

    NASA Astrophysics Data System (ADS)

    Xu, Z.; Zuo, D.

    2014-09-01

    The Wei River is the largest tributary of the Yellow River in China and it is suffering from water scarcity and water pollution. In order to quantify the amount of water resources in the study area, a hydrological modelling approach was applied by using SWAT (Soil and Water Assessment Tool), calibrated and validated with SUFI-2 (Sequential Uncertainty Fitting program) based on river discharge in the Wei River basin (WRB). Sensitivity and uncertainty analyses were also performed to improve the model performance. Water resources components of blue water flow, green water flow and green water storage were estimated at the HRU (Hydrological Response Unit) scales. Water resources in HRUs were also aggregated to sub-basins, river catchments, and then city/region scales for further analysis. The results showed that most parts of the WRB experienced a decrease in blue water resources between the 1960s and 2000s, with a minimum value in the 1990s. The decrease is particularly significant in the most southern part of the WRB (Guanzhong Plain), one of the most important grain production basements in China. Variations of green water flow and green water storage were relatively small on the spatial and temporal dimensions. This study provides strategic information for optimal utilization of water resources and planning of cultivating seasons in the Wei River basin.

  13. From the Mountains of the Moon to the Grand Renaissance: misinformation, disinformation and, finally, information for cooperation in the Nile River basin

    NASA Astrophysics Data System (ADS)

    Zaitchik, B. F.; Habib, S.; Anderson, M. C.; Ozdogan, M.

    2012-12-01

    The Nile River basin is shared by 11 nations and approximately 200 million people. Eight of the riparian States are defined as Least Developed Countries by the United Nations, and about 50% of the total basin population lives below the international poverty line. In addition, eight of the eleven countries have experienced internal or external wars in the past 20 years, six are predicted to be water scarce by 2025, and, at present, major water resource development projects are moving forward in the absence of a fully recognized basin-wide water sharing agreement. Nevertheless, the Nile basin presents remarkable opportunities for transboundary water cooperation, and today—notwithstanding significant substantive and perceived disagreements between stakeholders in the basin—this cooperation is beginning to be realized in topics ranging from flood early warning to hydropower optimization to regional food security. This presentation will provide an overview of historic and present challenges and opportunities for transboundary water management in the Nile basin and will present several case studies in which improved hydroclimatic information and communication systems are currently laying the groundwork for advanced cooperation. In this context climate change acts as both stress and motivator. On one hand, non-stationary hydrology is expected to tax water resources in the basin, and it undermines confidence in conventionally formulated water sharing agreements. On the other, non-stationarity is increasingly understood to be an exogenous threat to regional food and water security that will require informed, flexible cooperation between riparian states.

  14. Effects of land use and land cover on selected soil quality indicators in the headwater area of the Blue Nile basin of Ethiopia.

    PubMed

    Teferi, Ermias; Bewket, Woldeamlak; Simane, Belay

    2016-02-01

    Understanding changes in soil quality resulting from land use and land management changes is important to design sustainable land management plans or interventions. This study evaluated the influence of land use and land cover (LULC) on key soil quality indicators (SQIs) within a small watershed (Jedeb) in the Blue Nile Basin of Ethiopia. Factor analysis based on principal component analysis (PCA) was used to determine different SQIs. Surface (0-15 cm) soil samples with four replications were collected from five main LULC types in the watershed (i.e., natural woody vegetation, plantation forest, grassland, cultivated land, and barren land) and at two elevation classes (upland and midland), and 13 soil properties were measured for each replicate. A factorial (2 × 5) multivariate analysis of variance (MANOVA) showed that LULC and altitude together significantly affected organic matter (OM) levels. However, LULC alone significantly affected bulk density and altitude alone significantly affected bulk density, soil acidity, and silt content. Afforestation of barren land with eucalypt trees can significantly increase the soil OM in the midland part but not in the upland part. Soils under grassland had a significantly higher bulk density than did soils under natural woody vegetation indicating that de-vegetation and conversion to grassland could lead to soil compaction. Thus, the historical LULC change in the Jedeb watershed has resulted in the loss of soil OM and increased soil compaction. The study shows that a land use and management system can be monitored if it degrades or maintains or improves the soil using key soil quality indicators.

  15. Modeling the water budget of the Upper Blue Nile basin using the JGrass-NewAge model system and satellite data

    NASA Astrophysics Data System (ADS)

    Abera, Wuletawu; Formetta, Giuseppe; Brocca, Luca; Rigon, Riccardo

    2017-06-01

    The Upper Blue Nile basin is one of the most data-scarce regions in developing countries, and hence the hydrological information required for informed decision making in water resource management is limited. The hydrological complexity of the basin, tied with the lack of hydrometeorological data, means that most hydrological studies in the region are either restricted to small subbasins where there are relatively better hydrometeorological data available, or on the whole-basin scale but at very coarse timescales and spatial resolutions. In this study we develop a methodology that can improve the state of the art by using available, but sparse, hydrometeorological data and satellite products to obtain the estimates of all the components of the hydrological cycle (precipitation, evapotranspiration, discharge, and storage). To obtain the water-budget closure, we use the JGrass-NewAge system and various remote sensing products. The satellite product SM2R-CCI is used for obtaining the rainfall inputs, SAF EUMETSAT for cloud cover fraction for proper net radiation estimation, GLEAM for comparison with NewAge-estimated evapotranspiration, and GRACE gravimetry data for comparison of the total water storage amounts available in the whole basin. Results are obtained at daily time steps for the period 1994-2009 (16 years), and they can be used as a reference for any water resource development activities in the region. The overall water-budget analysis shows that precipitation of the basin is 1360 ± 230 mm per year. Evapotranspiration accounts for 56 % of the annual water budget, runoff is 33 %, storage varies from -10 to +17 % of the water budget.

  16. Improving satellite quantitative precipitation estimates through the use of high-resolution numerical weather predictions: Similarities and contrasts between the Alps and Blue Nile region

    NASA Astrophysics Data System (ADS)

    Bartsotas, Nikolaos; Nikolopoulos, Efthymios; Anagnostou, Emmanouil; Kallos, George

    2017-04-01

    Estimation of heavy precipitation events (HPEs) over high mountainous terrain is a particularly challenging task due to the limited availability of in-situ observations. Proper analysis and thorough understanding of the charac-teristics of HPE over complex terrain is thus hampered by insufficient precipitation information. Rain gauge networks usually present insufficient density and quality control issues in such areas. Radar rainfall estimates, wherever available, are heavily affected from terrain blockage. In this context, remote sensing has been attributed with a major role. However, this does not come without blemishes, as strong underestimation of precipitation associated with low-level orographic enhancement, introduces significant error in satellite estimates. In this study, we evaluate a satellite precipitation error-correction approach that can be implemented in the ab-sence of ground observations and it is based on utilization of precipitation information from high-resolution (1-2km) NWP simulations. Two quasi-global satellite precipitation products (CMORPH-8km and PERSIANN-4km) are used in more than 20 identified HPEs over two mountainous areas, the Alps and Ethiopia's Blue Nile. High-resolution atmospheric simulations from RAMS/ICLAMS are evaluated against rain gauge networks and radar estimates, then utilized to derive error correction functions for corresponding satellite precipitation data. Consequently, a PDF matching is applied and conclusions on the dependence of the method from synoptic at-mospheric conditions, which reveal to a certain degree the predictability of error properties, as well as the possi-bility of a global approach, are thoroughly discussed.

  17. Heavy metal biomonitoring and phytoremediation potentialities of aquatic macrophytes in River Nile.

    PubMed

    Fawzy, Manal Ahmed; Badr, Nadia El-sayed; El-Khatib, Ahmed; Abo-El-Kassem, Amany

    2012-03-01

    The concentrations of Cd, Cu, Pb, and Zn in sediments, water, and different plant organs of six aquatic vascular plant species, Ceratophyllum demersum L. Echinochloa pyramidalis (Lam.) Hitchc. & Chase; Eichhornia crassipes (Mart.) Solms-Laub; Myriophyllum spicatum L.; Phragmites australis (Cav.) Trin. ex Steud; and Typha domingensis (Pers.) Poir. ex Steud, growing naturally in the Nile system (Sohag Governorate), were investigated. The aim was to define which species and which plant organs exhibit the greatest accumulation and evaluate whether these species could be usefully employed in biomonitoring and phytoremediation programs. The recorded metals in water samples were above the standard levels of both US Environmental Protection Agency and Egyptian Environmental Affairs Agency except for Pb. The concentrations of heavy metals in water, sediments, and plants possess the same trend: Zn > Cu > Pb > Cd which reflects the biomonitoring potentialities of the investigated plant species. Generally, the variation of heavy element concentrations in water and sediments in relation to site and season, as assessed by two-way repeated measured ANOVA, was significant (p < 0.05). However, insignificant variations were observed in the concentrations of Pb and Cd in sediments in relation to season and of Cu and Zn in relation to site. Results also showed that the selectivity of the heavy elements for the investigated plants varied significantly (p < 0.05) with species variation. The accumulation capability of the investigated species could be arranged according to this pattern: C. demersum > E. crassipes > M. spicatum > E. pyramidalis > T. domingensis > P. australis. On the basis of the element concentrations, roots of all the studied species contain higher concentrations of Cu and Zn than shoots while leaves usually acquire the highest concentrations of Pb. Cd concentrations among different plant organs are comparable except in M. spicatum where the highest Cd concentrations

  18. Estimated flood-inundation mapping for the Lower Blue River in Kansas City, Missouri, 2003-2005

    USGS Publications Warehouse

    Kelly, Brian P.; Rydlund, Jr., Paul H.

    2006-01-01

    The U.S. Geological Survey, in cooperation with the city of Kansas City, Missouri, began a study in 2003 of the lower Blue River in Kansas City, Missouri, from Gregory Boulevard to the mouth at the Missouri River to determine the estimated extent of flood inundation in the Blue River valley from flooding on the lower Blue River and from Missouri River backwater. Much of the lower Blue River flood plain is covered by industrial development. Rapid development in the upper end of the watershed has increased the volume of runoff, and thus the discharge of flood events for the Blue River. Modifications to the channel of the Blue River began in late 1983 in response to the need for flood control. By 2004, the channel had been widened and straightened from the mouth to immediately downstream from Blue Parkway to convey a 30-year flood. A two-dimensional depth-averaged flow model was used to simulate flooding within a 2-mile study reach of the Blue River between 63rd Street and Blue Parkway. Hydraulic simulation of the study reach provided information for the design and performance of proposed hydraulic structures and channel improvements and for the production of estimated flood-inundation maps and maps representing an areal distribution of water velocity, both magnitude and direction. Flood profiles of the Blue River were developed between Gregory Boulevard and 63rd Street from stage elevations calculated from high water marks from the flood of May 19, 2004; between 63rd Street and Blue Parkway from two-dimensional hydraulic modeling conducted for this study; and between Blue Parkway and the mouth from an existing one-dimensional hydraulic model by the U.S. Army Corps of Engineers. Twelve inundation maps were produced at 2-foot intervals for Blue Parkway stage elevations from 750 to 772 feet. Each map is associated with National Weather Service flood-peak forecast locations at 63rd Street, Blue Parkway, Stadium Drive, U.S. Highway 40, 12th Street, and the Missouri River

  19. Groundwater model of the Blue River basin, Nebraska-Twenty years later

    USGS Publications Warehouse

    Alley, W.M.; Emery, P.A.

    1986-01-01

    Groundwater flow models have become almost a routine tool of the practicing hydrologist. Yet, surprisingly little attention has been given to true verification analysis of studies using these models. This paper examines predictions for 1982 of water-level declines and streamflow depletions that were made in 1965 using an electric analog groundwater model of the Blue River basin in southeastern Nebraska. Analysis of the model's predictions suggests that the analog model used too low an estimate of net groundwater withdrawals, yet overestimated water-level declines. The model predicted that almost all of the net groundwater pumpage would come from storage in the Pleistocene aquifer within the Blue River basin. It appears likely that the model underestimated the contributions of other sources of water to the pumpage, and that the aquifer storage coefficients used in the model were too low. There is some evidence that groundwater pumpage has had a greater than predicted effect on streamflow. Considerable uncertainty about the basic conceptualization of the hydrology of the Blue River basin greatly limits the reliability of groundwater models developed for the basin. The paper concludes with general perspectives on groundwater modeling gained from this post-audit analysis. ?? 1986.

  20. Occurrence, transport, and fate of trace elements, Blue River Basin, Summit County, Colorado: an integrated approach

    USGS Publications Warehouse

    Apodaca, L.E.; Driver, N.E.; Bails, J.B.

    2000-01-01

    Mining activities in the Blue River Basin, Summit County, Colorado, have affected the trace-element chemistry and biota along French Gulch and the Blue River. Elevated concentrations of As, Cd, Cu, Pb, and Zn were present in the bed and suspended sediments. Bed sediment trace-element concentrations were high in the streams in and near mining activities in the basin and remained high as water flowed into Dillon Reservoir about 3.5 km downstream. Bed-sediment (< 63 μm) data were useful in assessing the distribution of trace elements in the basin. Suspended-sediment measurements provided information as to the transport of the trace elements. Filtered (< 0.45 μm) water-column trace-element concentrations were orders of magnitude less than the sediment concentrations. Concentrations of Cd and Zn in the water column at some sites exceeded stream water-quality standards. Elevated trace-element concentrations in the sediment and water column are a source of contamination and must be considered in water-quality management of the Blue River Basin.

  1. Gastric nematodes of nile crocodiles, Crocodylus niloticus Laurenti, 1768, in the Okavango River, Botswana.

    PubMed

    Junker, K; Wallace, K; Leslie, A J; Boomker, J

    2006-06-01

    The ascaridoid nematodes Dujardinascaris madagascariensis Chabaud & Caballero, 1966, Dujardinascaris dujardini (Travassos, 1920), Gedoelstascaris vandenbrandeni (Baylis, 1929) Sprent, 1978 and Multicaecum agile (Wedl, 1861) Baylis, 1923 were recovered from the stomach contents of Crocodylus niloticus Laurenti, 1768 from the Okavango River, Botswana, together with Eustrongylides sp., a dioctophymatoid nematode usually parasitizing piscivorous birds. Dujardinascaris madagascariensis was present in most of the infected hosts, while the remaining species were mostly represented in single collections in one to three hosts. All four ascaridoid nematodes represent new geographic records.

  2. Glacially influenced sedimentation in the late Neoproterozoic Mechum River Formation, Blue Ridge province, Virginia

    NASA Astrophysics Data System (ADS)

    Bailey, Christopher M.; Peters, Shanan E.

    1998-07-01

    The late Neoproterozoic (ca. 700 730 Ma) Mechum River Formation is exposed as a structural inlier within Grenvillian basement in the Blue Ridge province of central Virginia, United States. The southern portion of the Mechum River belt preserves evidence of glaciomarine sedimentation at the margin and basinward of grounding-line fans. Subaqueous glacial till, coarse-grained rhythmites, and dropstones record the incursion of ice into the basin. Marine deposition is evidenced by persistent laminations (cyclopsams) in rhythmically bedded diamictite and possibly by tidally pumped, distal turbidites in laminated mudstones. Glaciomarine sedimentation in the Mechum River Formation may have been coeval with Sturtian-Rapitan glaciations in northwestern Laurentia and Australia, and provides further evidence for a globally cold climate during the late Neoproterozoic.

  3. Evaluation of climate anomalies impacts on the Upper Blue Nile Basin in Ethiopia using a distributed and a lumped hydrologic model

    NASA Astrophysics Data System (ADS)

    Elsanabary, Mohamed Helmy; Gan, Thian Yew

    2015-11-01

    Evaluating the climate anomalies impacts on the Upper Blue Nile Basin (UBNB), Ethiopia, a large basin with scarce hydroclimatic data, through hydrologic modeling is a challenge. A fully distributed, physically-based model, a modified version of the Interactions Soil-Biosphere Atmosphere model of Météo France (MISBA), and a lumped, conceptual rainfall-runoff Sacramento model, SAC-SMA of the US National Weather Service, were used to simulate the streamflow of UBNB. To study the potential hydrologic effect of climate anomalies on the UBNB, rainfall and temperature data observed when climate anomalies were active, were resampled and used to drive MISBA and SAC-SMA. To obtain representative, distributed precipitation data in mountainous basins, it was found that a 3% adjustment factor for every 25 m rise in elevation was needed to orographically correct the rainfall over UBNB. The performance of MISBA applied to UBNB improved after MISBA was modified so that it could simulate evaporation loss from the canopy, providing coefficient of determination (R2) = 0.58, and root mean square error (RMSE) = 0.34 m3/s in comparison with the observed streamflow. In contrast, the performance of SAC-SMA at the calibration run and the validation run is better than that of MISBA, such that R2 is 0.79 for calibration and 0.82 for validation even though it models the hydrology of UBNB in a lumped, conceptual framework as against the physically-based, fully distributed framework of MISBA. El Niño tends to decrease the June-September rainfall but increase the February-May rainfall, while La Niña has opposite effect on the rainfall of UBNB. Based on the simulations of MISBA and SAC-SMA for UBNB, La Niña and Indian Ocean Dipole (IOD) tend to have a wetting effect while El Niño has a drying effect on the streamflow of the UBNB. In addition, El Niño Southern Oscillation (ENSO) and IOD increase the streamflow variability more than changing the magnitude of streamflow. The results provide

  4. Sensitivity of the weather research and forecasting model to parameterization schemes for regional climate of Nile River Basin

    NASA Astrophysics Data System (ADS)

    Tariku, Tebikachew Betru; Gan, Thian Yew

    2017-08-01

    Regional climate models (RCMs) have been used to simulate rainfall at relatively high spatial and temporal resolutions useful for sustainable water resources planning, design and management. In this study, the sensitivity of the RCM, weather research and forecasting (WRF), in modeling the regional climate of the Nile River Basin (NRB) was investigated using 31 combinations of different physical parameterization schemes which include cumulus (Cu), microphysics (MP), planetary boundary layer (PBL), land-surface model (LSM) and radiation (Ra) schemes. Using the European Centre for Medium-Range Weather Forecast (ECMWF) ERA-Interim reanalysis data as initial and lateral boundary conditions, WRF was configured to model the climate of NRB at a resolution of 36 km with 30 vertical levels. The 1999-2001 simulations using WRF were compared with satellite data combined with ground observation and the NCEP reanalysis data for 2 m surface air temperature (T2), rainfall, short- and longwave downward radiation at the surface (SWRAD, LWRAD). Overall, WRF simulated more accurate T2 and LWRAD (with correlation coefficients >0.8 and low root-mean-square error) than SWRAD and rainfall for the NRB. Further, the simulation of rainfall is more sensitive to PBL, Cu and MP schemes than other schemes of WRF. For example, WRF simulated less biased rainfall with Kain-Fritsch combined with MYJ than with YSU as the PBL scheme. The simulation of T2 is more sensitive to LSM and Ra than to Cu, PBL and MP schemes selected, SWRAD is more sensitive to MP and Ra than to Cu, LSM and PBL schemes, and LWRAD is more sensitive to LSM, Ra and PBL than Cu, and MP schemes. In summary, the following combination of schemes simulated the most representative regional climate of NRB: WSM3 microphysics, KF cumulus, MYJ PBL, RRTM longwave radiation and Dudhia shortwave radiation schemes, and Noah LSM. The above configuration of WRF coupled to the Noah LSM has also been shown to simulate representative regional

  5. Hayden-Blue River 345-kV transmission line project, Colorado

    SciTech Connect

    Not Available

    1982-09-01

    Tri-State Generation and Transmission Association, Inc., Colorado-Ute Electric Association, Inc., Platte River Power Authority, and Western Area Power Administration propose to construct and operate approximately 90 miles of 345-kilovolt (kV) transmission line between Hayden and the Blue River Valley in Colorado. The project would involve expansion of existing substation facilities at Hayden and construction of two new substations. The line would be operated at 230 kV initially. Estimated cost of the project is $37.8 million. The new line and substation facilities would provide a backup transmission path, satisfy the long-term needs in meeting the energy requirements, improve system reliability, improve system stability for the Craig and Hayden generating stations, and leave the existing 115-kV and 138-kV lines in operation to provide additional transmission capacity that would function as backup transmission during an outage on another line. Minute amounts of lands would be displaced. Construction activities would disturb critical ranges for elk and mule deer, elk calving areas, and the mating and nesting areas of greater sandhill cranes, great blue herons, sage grouse, golden eagles, and prairie falcons. Management of timberland would damage natural vegetation. The line would traverse 3.1 miles of flood-prone area, and as many as three transmission towers would lie within the floodplain of the Colorado River. The visual quality of land crossed by the line would be degraded somewhat.

  6. The Impact of Water Scarcity on Egyptian National Security and on Regional Security in the Nile River Basin

    DTIC Science & Technology

    2012-06-08

    powers. Sudan, the CDR, Rwanda, Burundi , Ethiopia and Eritrea are the most vulnerable to regional interventions. The governments which intervene most...include Uganda, Rwanda, Burundi , Kenya (from inside the Nile Basin), South Africa, Nigeria, Israel, Iran, Zimbabwe and Angola (from outside the

  7. Flood-inundation maps for the Big Blue River at Shelbyville, Indiana

    USGS Publications Warehouse

    Fowler, Kathleen K.

    2017-02-13

    Digital flood-inundation maps for a 4.1-mile reach of the Big Blue River at Shelbyville, Indiana, were created by the U.S. Geological Survey (USGS) in cooperation with the Indiana Office of Community and Rural Affairs. The floodinundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at https://water. usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the Big Blue River at Shelbyville, Ind. (station number 03361500). Near-real-time stages at this streamgage may be obtained from the USGS National Water Information System at https://waterdata. usgs.gov/ or the National Weather Service (NWS) Advanced Hydrologic Prediction Service at https://water.weather.gov/ ahps/, which also forecasts flood hydrographs at this site (SBVI3). Flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The hydraulic model was calibrated by using the most current stage-discharge relation at the Big Blue River at Shelbyville, Ind., streamgage. The calibrated hydraulic model was then used to compute 12 water-surface profiles for flood stages referenced to the streamgage datum and ranging from 9.0 feet, or near bankfull, to 19.4 feet, the highest stage of the current stage-discharge rating curve. The simulated water-surface profiles were then combined with a Geographic Information System digital elevation model (derived from light detection and ranging [lidar] data having a 0.98-foot vertical accuracy and 4.9-foot horizontal resolution) to delineate the area flooded at each water level. The availability of these maps, along with Internet information regarding current stage from the USGS streamgage at the Big Blue River at Shelbyville, Ind., and forecasted stream stages from the NWS, will provide emergency management personnel and residents with information that is critical for flood response

  8. Fluvial sediment and chemical quality of water in the Little Blue River basin, Nebraska and Kansas

    USGS Publications Warehouse

    Mundorff, J.C.; Waddell, K.M.

    1966-01-01

    The Little Blue River drains about 3,37)0 square miles in south-central Nebraska and north-central Kansas. The uppermost bedrock in the basin is limestone and shale of Permian age and sandstone, shale, and limestone of Cretaceous age. Bedrock is exposed in many places in the lower one-third of the basin but elsewhere is buried beneath a thin to thick mantle of younger sediments, mostly of Quaternary age. These younger sediments are largely fluvial and eolian deposits but also include some glacial till. Consisting in large part of sand and gravel, the fluvial deposits are an important source of ground-water supplies throughout much of the upper two-thirds of the basin. Loess, an eolian deposit of clayey silt, is by far the most widespread surficial deposit. The climate is continental. Temperatures ranging from -38 ? F to 118 ? F have been recorded in the basin. Average annual precipitation as low as 10.31 and as high as 49.32 inches has been recorded. During most years in the period 1956-62, when nearly all the water-quality data were obtained, annual precipitation and annual runoff were greater than normal. Flow-duration data indicate, however, that the flow distribution for the period was near normal. The Little Blue River has the same suspended-sediment characteristics as nearly all unregulated streams in the Great Plains--a wide range in concentrations, low concentrations during low-flow periods, and high concentrations during almost all periods of significant overland runoff. The maximum instantaneous concentration normally occurs many hours before maximum water discharge during any given rise in stage; the maximum daily mean concentration during any given year normally occurs at a moderate stream stage, not during a major flood. Suspended-sediment data for Little Blue River near Deweese, Nebr., which receives drainage from the upstream third of the basin, approximately, show that during the 1!}57-61 water years concentrations of 100 ppm (parts per million) or

  9. Heterobothrium lineatus (Monogenea: Diclidophoridae) infecting the gills of the Nile puffer Tetraodon lineatus (Pisces: Tetraodontidae) from the River Nile, Egypt with a new localit record: a light and scanning electron microscopic study.

    PubMed

    Morsy, Kareem S; Khalil, Mona Fathi; Gamil, Irene Sameh; Elebiarie, Ahmed Salem; Ibrahim, Rokia Mahmoud

    2013-12-01

    Heterobothrium lineatus (Monogenea: Diclidophoridae) is described from the gills of Tetraodon lineatus collected from the River Nile at Helwan governorate, Egypt as a new locality record. The morphology and morphometric characterization of the recovered worms were described by means of light and scanning electron microscopy. Twenty two out 35 with a percentage of 62.9% of the examined fish were infected with Heterobothrium sp. (the intensity of infection was about ten worms per fish in general). Most of the infected fish had very pale gills and showed symptoms of anemia. Morphologically, the adult worms were elongated with anterior pointed and posterior broad ends, it measured 1.15-1.76 (1.52 +/- 0.02) mm in length x 0.28-0.39 (0.29 +/- 0.02) mm in width. Two buccal organs situated anteriorly around mouth opening were shown by light and scanning electron microscopy. Haptor subdivided into four pairs of clamps without isthmus separating it from body. The recovered worm differed from the previously species in the same genus by small dimensions of the measurements and presence of a copulatory organ armed with 7-11 genital hooks. Also, it is distinguished from H. tetrodonis and H. okamotoi by absence of a distinct isthmus, and resembled H. lamothei from gills of Sphoeroides testodineus in Mexico and H. lineatus from T. lineatus in Egypt in general appearance and presence of rectangular haptor with the fourth pair of clamps smaller than the previous ones.

  10. Millennial-scale sea surface temperature changes in the eastern Mediterranean (Nile River Delta region) over the last 27,000 years

    NASA Astrophysics Data System (ADS)

    Castañeda, Isla S.; Schefuß, Enno; Pätzold, Jürgen; Sinninghe Damsté, Jaap S.; Weldeab, Syee; Schouten, Stefan

    2010-03-01

    In this study we utilize two organic geochemical proxies, the U37k‧ index and TEX86, to examine past sea surface temperatures (SST) from a site located near the Nile River Delta in the eastern Mediterranean (EM) Sea. The U37k‧ and TEX86 records generally are in agreement and indicate SST ranges of 14°C-26°C and 14°C-28°C, respectively, during the last 27 cal ka. During the Holocene, TEX86-based SST estimates are usually higher than U37k‧-based SST estimates, which is likely due to seasonal differences between the timing of the haptophyte and crenarchaeota blooms in the EM and is related to the onset of the modern flow regime of the Nile River. Both records show that SST varied on centennial to millennial timescales in response to global climate events, i.e., cooling during the Last Glacial Maximum (LGM), Heinrich event 1 (H1), and the Younger Dryas (YD) and warming during the Bølling-Allerød and in the early Holocene during deposition of sapropel S1. The H1 cooling was particularly severe and is marked by a drop in SST of ˜4.5°C in comparison to pre-H1 SST, with temperatures >1°C cooler than during the LGM. In contrast to high-latitude and western Mediterranean records, which indicate both an abrupt onset and termination of the YD event, the transition from the YD to the Holocene was much more gradual in the EM.

  11. Neodymium Isotope data for Foraminifera Indicates Increased Nile Outflow During Mediterranean Anoxic Events

    NASA Astrophysics Data System (ADS)

    Scrivner, A. E.; Vance, D.; Rohling, E. J.

    2001-12-01

    The environmental conditions leading to deep water anoxia in the Eastern Mediterranean during sapropel formation remain controversial. It is broadly accepted that sapropels are the result of either water column stagnation or increased export production, or both. Oxygen isotopes indicate reduced surface-water salinities during sapropel formation, which would have facilitated deep-water stagnation via convective stabilisation of the water column. A number of sources for the additional freshwater have been proposed, including glacial meltwater influx, increased outflow from European rivers, increased precipitation over the Mediterranean region as a whole, and increased Nile outflow due to intensification of the African monsoon. Oxygen isotopes by themselves cannot fully distinguish between these various possibilities. Though the exact mode of incorporation of neodymium (Nd) into foraminiferal tests remains a matter of debate, Nd isotopes in sedimentary planktonic foraminifera clearly record those in surface seawater and not any other part of the water column or the sediment1,2. Here we present Nd isotopic data for both the present-day Nile and for sedimentary foraminifera from ODP core 967, which demonstrate a significant increase in Nile outflow during the formation of sapropel S5. Samples of Nile river water were collected from the Sudan in the dry season and analysed for neodymium isotope compositions. These analyses clearly show that the River Nile has both a very high neodymium concentration compared to the Mediterranean and a distinct 143Nd/144Nd ratio. \\epsilonNd (defined as ((143Nd/144Ndsample)/(143Nd/ 144NdCHUR)-1)\\times104) for the main Nile around and below Khartoum is -3. In the wet season (sampling in progress), the Blue Nile (\\epsilonNd = +1) dominates over the White Nile (\\epsilonNd = -16) and the total Nile discharge is vastly greater, so that the annually-integrated \\epsilonNd of the main Nile should be even higher than -3. In contrast, the

  12. Institutional and legal arrangements in the Nile river basin: suggestions to improve the current situation toward adaptive integrated water resources management.

    PubMed

    Abdalla, Khalid Mohamed El Hassan

    2008-01-01

    A comparative study was conducted in this work in order to investigate the current situation in the Nile river basin (NRB) regarding the institutional and legal arrangements needed to support the adaptive integrated water resources management (AIWRM) strategy. Two similar river basins were selected to achieve this comparison and to introduce suggestions to reform the current situation in the basin. Before that, the ideal situation is investigated to be as a yardstick for the desired situation. The study indicated that the necessary AIWRM criteria may include regulatory as well as implementation organizations that support shared-vision reaching with its all necessary features (cooperation, stakeholders' participation, subsidiarity, and information and knowledge exchange). Thus the main features of the desired situations regarding AIWRM in river basins are stakeholders' participation, learning-driven ability, quick response to risks and uncertainties, and finally a legal framework that could support these criteria. Although the AIWRM criteria seem to be satisfied in NRB, the basin lacks the necessary regulatory institutions as well as the legal framework. According to this, this study recommends to reform the current situation in NRB by creating regulator institutions (policy and decision making level) as well a legal framework to legitimate them.

  13. The modern Nile sediment system: Processes and products

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Vezzoli, Giovanni; El Kammar, Ahmed

    2015-12-01

    We trace compositional changes of Nile sediments for 7400 km, from their sources in equatorial rift highlands of Burundi and Rwanda to their sink in the Mediterranean Sea. All chemical and physical controls on sediment petrography, mineralogy and geochemistry, including weathering, grain-size, hydraulic sorting, mechanical breakdown, anthropic impact, mixing and recycling are investigated in detail. The Nile course is controlled along its entire length by the East African-Red Sea Rift. In this anorogenic setting, detritus is derived in various proportions from volcanic fields associated with tectonic extension (Anorogenic Volcanic provenance) and from igneous, metamorphic and sedimentary rocks uplifted on the rift shoulders or exposed on the craton (Continental Block provenance). The entire spectrum of such detrital signatures is displayed in the Nile catchment. Volcaniclastic Atbara sand is generated by focused erosion of the Ethiopian basaltic plateau in semiarid climate, whereas quartzose White Nile sand reflects low erosion rates, extensive weathering and sediment trapping in lakes and swamps at equatorial to subequatorial latitudes. In the main Nile, as in its main tributary the Blue Nile, suspended load is volcaniclastic, whereas feldspatho-quartzose bedload is derived largely from basement sources, with fine to medium-grained eolian sand added along the lower course. Mixing of detrital populations with different provenance and grain size is reflected in diverse violations of settling-equivalence relationships in fluvial and deltaic sediments. Sediment delivery from Sudan has been cut off after closure of the Aswan High Dam and accelerated erosion of deltaic cusps is leading to local formation of placer lags dominated by ultradense Fe-Ti-Cr oxides, but mineralogical changes caused by man's radical modification of fluvial regimes have been minor so far. In beaches of Sinai, Gaza and Israel, the Nile volcaniclastic trace gets progressively diluted by quartzose

  14. Big Blue River at Shelbyville, Indiana flood-inundation geospatial datasets​

    USGS Publications Warehouse

    Fowler, Kathleen K.

    2017-01-01

    Digital flood-inundation maps for a 4.1-mile reach of the Big Blue River at Shelbyville, Indiana, were created by the U.S. Geological Survey (USGS) in cooperation with the Indiana Office of Community and Rural Affairs. The flood-inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the Big Blue River at Shelbyville, Indiana (station number 03361500). Near-real-time stages at this streamgage may be obtained from the USGS National Water Information System at http://waterdata.usgs.gov/ or the National Weather Service (NWS) Advanced Hydrologic Prediction Service at http://water.weather.gov/ahps/, which also forecasts flood hydrographs at this site (SBVI3).Flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The hydraulic model was calibrated by using the most current stage-discharge relation at the Big Blue River at Shelbyville, Ind., streamgage. The calibrated hydraulic model was then used to compute 12 water-surface profiles for flood stages referenced to the streamgage datum and ranging from 9.0 feet, or near bankfull, to 19.4 feet, the highest stage of the current stage-discharge rating curve. The simulated water-surface profiles were then combined with a Geographic Information System digital elevation model (derived from light detection and ranging [lidar] data having a 0.98-foot vertical accuracy and 4.9-foot horizontal resolution) to delineate the area flooded at each water level.The attached files on this landing page are the inputs and outputs for the U.S. Army Corps of Engineers HEC-RAS model used to create flood-inundation maps for the referenced report, https://doi.org/10.3133/sir20165166. There are two child items that contain final geospatial datasets for the flood-inundation maps

  15. Measuring and Developing Methods of Attitude and Motivational Change in Implementing the Big Blue River Basin Water Plan.

    ERIC Educational Resources Information Center

    McPartland, Edward J.

    The northern portion of the Big Blue River Basin is located in southeastern Nebraska, ranking among the best farm land in the state. Despite its excellent resources for agriculture, the basin suffers from a number of problems related to water and agriculture, such as: (1) precipitation varies during the growing season, stimulating the demand to…

  16. Economic implications for management of structural retention on harvest units at the Blue River Ranger District, Willamette National Forest, Oregon.

    Treesearch

    James F. Weigand; A. Lynn Burditt

    1992-01-01

    Timber sales offered at the Blue River Ranger District since the 1988 introduction of management for stand structural retention were studied to describe and quantify, where possible, economic implications of that management. Values for the potential lumber from merchantable green trees ranged from $102 to $1114 per acre among the harvest units surveyed thus far....

  17. Microbial Source Tracking as a Tool for TMDL Development, Little Blue River in Independence, Missouri

    USGS Publications Warehouse

    Christensen, Eric D.; Bushon, Rebecca N.; Brady, Amie M.G.

    2013-01-01

    The Little Blue River in Jackson County, Missouri has been listed by the Missouri Department of Natural Resources as impaired by bacteria for the protection of aquatic life and contact recreation from urban point and nonpoint sources. The Clean Water Act requires that a total maximum daily load (TMDL) for Escherichia coli (E. coli) be developed. Over a 5-year period, 108 base-flow, 87 stormflow, 48 fecal source, and 12 sewage influent samples were collected and analyzed for E. coli and Bacteroides general and host-associated microbial source tracking (MST) genetic markers. Less than half of the main-stem base-flow samples exceeded the E. coli state standard, whereas, all of the stormflow samples exceeded the standard during the recreation season (April through October). Both E. coli and MST markers were detected more frequently and at higher concentrations in stormflow samples. Only 14 percent of samples with E. coli detections greater than the Missouri state standard of 206 colonies per 100 milliliters had the human-associated Bacteroides marker as the only identified marker; therefore, Little Blue River TMDL development may require a broader scope beyond the municipal separate storm sewer system if bacteria sources are to be identified and addressed. Fecal samples showed a greater specificity with the human-associated marker than the dog- or ruminant-associated Bacteroides markers; however, false positives were at least one order of magnitude lower than true positives. MST data may be a useful tool for identifying probable sources of contamination and directing TMDL strategies.

  18. Socioeconomic dynamics of water quality in the Egyptian Nile

    NASA Astrophysics Data System (ADS)

    Malik, Maheen; Nisar, Zainab; Karakatsanis, Georgios

    2016-04-01

    The Nile River remains the most important source of freshwater for Egypt as it accounts for nearly all of the country's drinking and irrigation water. About 95% of the total population is accounted to live along the Banks of the Nile(1). Therefore, water quality deterioration in addition to general natural scarcity of water in the region(2) is the main driver for carrying out this study. What further aggravates this issue is the water conflict in the Blue Nile region. The study evaluates different water quality parameters and their concentrations in the Egyptian Nile; further assessing the temporal dynamics of water quality in the area with (a) the Environmental Kuznets Curve (EKC)(3) and (b) the Jevons Paradox (JP)(4) in order to identify water quality improvements or degradations using selected socioeconomic variables(5). For this purpose various environmental indicators including BOD, COD, DO, Phosphorus and TDS were plotted against different economic variables including Population, Gross Domestic Product (GDP), Annual Fresh Water Withdrawal and Improved Water Source. Mathematically, this was expressed by 2nd and 3rd degree polynomial regressions generating the EKC and JP respectively. The basic goal of the regression analysis is to model and highlight the dynamic trend of water quality indicators in relation to their established permissible limits, which will allow the identification of optimal future water quality policies. The results clearly indicate that the dependency of water quality indicators on socioeconomic variables differs for every indicator; while COD was above the permissible limits in all the cases despite of its decreasing trend in each case, BOD and phosphate signified increasing concentrations for the future, if they continue to follow the present trend. This could be an indication of rebound effect explained by the Jevons Paradox i.e. water quality deterioration after its improvement, either due to increase of population or intensification

  19. Detection of mutagens and BaPMO inducers in river water using the Blue Cotton adsorption technique.

    PubMed

    Britvić, Smiljana; Hackenberger, Branimir K; Jarić, Davorka; Stepić, Sandra

    2012-03-01

    Induction of Mixed Function Oxidase (MFO) activity and bioactivation potential were measured in experimental carp and in native fish species from two rivers with different pollution level (Sava and Mrežnica). The experimental carp were intraperitoneally exposed to various water volume equivalents of Blue Cotton extracts from both rivers. The induction of MFO measured as a Benzo(a)pyrene monooxygenase (BaPMO) activity was increased up to 9.3-fold in experimental carp and up to 11.3-fold in native fish from Sava River, whereas the values from Mrežnica River showed only a slight increase when compared with the control (highest increase of 1.8-fold in nose carp). Accordingly, bioactivation potential using modified Ames test was higher in both experiments with Sava River. Both measured parameters in experimental carp increased in a dose-dependent manner in accordance to river volume equivalents. Different induction potential of native fish species comparable between two rivers confirmed the known possibility of their usage in biomonitoring studies. These results give qualitatively a new support to the idea of using Blue Cotton extraction technique combined with induction of MFO activity and Ames test in fish as a good biomarker for assessing risk of exposure to mutagens/carcinogens such as Polycyclic Aromatic Hydrocarbons (PAHs), especially due to the simplicity and cost-effectiveness of these methods.

  20. Water quality in the Blue River basin, Kansas City metropolitan area, Missouri and Kansas, July 1998 to October 2004

    USGS Publications Warehouse

    Wilkison, Donald H.; Armstrong, Daniel J.; Norman, Richard D.; Poulton, Barry C.; Furlong, Edward T.; Zaugg, Steven D.

    2006-01-01

    Water-quality data were collected from sites in the Blue River Basin from July 1998 to October. Sites upstream from wastewater-treatment plants or the combined sewer system area had lower concentrations of total nitrogen, phosphorus, organic wastewater compounds, and pharmaceuticals, and more diverse aquatic communities. Sites downstream from wastewater-treatment plants had the largest concentrations and loads of nutrients, organic wastewater compounds, and pharmaceuticals. Approximately 60 percent of the total nitrogen and phosphorus in Blue River originated from the Indian Creek, smaller amounts from the upper Blue River (from 28 to 16 percent), and less than 5 percent from Brush Creek. Nutrient yields from the Indian Creek and the middle Blue River were significantly greater than yields from the upper Blue River, lower Brush Creek, the outside control site, and other U.S. urban sites. Large concentrations of nutrients led to eutrophication of impounded Brush Creek reaches. Bottom sediment samples collected from impoundments generally had concentrations of organic wastewater and pharmaceutical compounds equivalent to or greater than, concentrations observed in streambed sediments downstream from wastewater-treatment plants. Bacteria in streams largely was the result of nonpoint-source contributions during storms. Based on genetic source-tracking, average contributions of in-stream Esherichia coli bacteria in the basin from dogs ranged from 26-32 percent of the total concentration, and human sources ranged from 28-42 percent. Macro invertebrate diversity was highest at sites with the largest percentage of upstream land use devoted to forests and grasslands. Declines in macro invertebrate community metrics were correlated strongly with increases in several, inter-related urbanization factors.

  1. Water Quality in the Blue River Basin, Kansas City Metropolitan Area, Missouri and Kansas, July 1998 to October 2004

    USGS Publications Warehouse

    Wilkison, Donald H.; Armstrong, Daniel J.; Norman, Richard D.; Polton, Barry C.; Furlong, Edward T.; Zaugg, Steven D.

    2006-01-01

    Water-quality data were collected from sites in the Blue River Basin from July 1998 to October. Sites upstream from wastewater-treatment plants or the combined sewer system area had lower concentrations of total nitrogen, phosphorus, organic wastewater compounds, and pharmaceuticals, and more diverse aquatic communities. Sites downstream from wastewater-treatment plants had the largest concentrations and loads of nutrients, organic wastewater compounds, and pharmaceuticals. Approximately 60 percent of the total nitrogen and phosphorus in Blue River originated from the Indian Creek, smaller amounts from the upper Blue River (from 28 to 16 percent), and less than 5 percent from Brush Creek. Nutrient yields from the Indian Creek and the middle Blue River were significantly greater than yields from the upper Blue River, lower Brush Creek, the outside control site, and other U.S. urban sites. Large concentrations of nutrients led to eutrophication of impounded Brush Creek reaches. Bottom sediment samples collected from impoundments generally had concentrations of organic wastewater and pharmaceutical compounds equivalent to or greater than, concentrations observed in streambed sediments downstream from wastewater-treatment plants. Bacteria in streams largely was the result of nonpoint-source contributions during storms. Based on genetic source-tracking, average contributions of in-stream Esherichia coli bacteria in the basin from dogs ranged from 26-32 percent of the total concentration, and human sources ranged from 28-42 percent. Macro invertebrate diversity was highest at sites with the largest percentage of upstream land use devoted to forests and grasslands. Declines in macro invertebrate community metrics were correlated strongly with increases in several, inter-related urbanization factors.

  2. A distal 140 kyr sediment record of Nile discharge and East African monsoon variability

    NASA Astrophysics Data System (ADS)

    Ehrmann, Werner; Schmiedl, Gerhard; Seidel, Martin; Krüger, Stefan; Schulz, Hartmut

    2016-03-01

    Clay mineral assemblages in a sediment core from the distal Nile discharge plume off Israel have been used to reconstruct the late Quaternary Nile sediment discharge into the eastern Mediterranean Sea (EMS). The record spans the last ca. 140 kyr. Smectite abundances indicate the influence of the Blue Nile and the Atbara River that have their headwaters in the volcanic rocks of the Ethiopian Highlands. Kaolinite abundances indicate the influence of wadis, which contribute periodically to the suspension load of the Nile. Due to the geographical position, the climate and the sedimentary framework of the EMS is controlled by two climate systems. The long-term climate regime was governed by the African monsoon that caused major African humid periods (AHPs) with enhanced sediment discharge at 132 to < 126 (AHP 5), 116 to 99 (AHP4), and 89 to 77 ka (AHP3). They lasted much longer than the formation of the related sapropel layers S5 (> 2 kyr), S4 (3.5 kyr), and S3 (5 kyr). During the last glacial period (Marine Isotope Stages (MISs) 4-2), the long-term changes in the monsoonal system were superimposed by millennial-scale changes in an intensified midlatitude glacial system. This climate regime caused short but pronounced drought periods in the Nile catchment, which are linked to Heinrich events and alternate with more humid interstadials. The clay mineral record further implies that feedback mechanisms between vegetation cover and sediment discharge of the Nile are detectable but of minor importance for the sedimentary record in the southeastern Mediterranean Sea during the investigated African humid periods.

  3. Controls on phosphorous mobility in the Potomac River near the Blue Plains wastewater treatment plant

    USGS Publications Warehouse

    Hearn,, Paul P.

    1985-01-01

    The Blue Plains wastewater treatment plant is the largest point source of phosphorus in the Potomac River basin, discharging an average of 2 metric tons of phosphorus into the river each day in 1980. An intensive study of the water and sediments in the vicinity of the treatment plant was conducted in 1979-80 in order to characterize the major factors controlling the mobility of effluent-derived phosphorus in the area. The transport of phosphorus near the treatment plant was found to be affected by the circulation regime, by inorganic adsorption reactions with sediments, and by metabolic uptake and release by phytoplankton. The effect of river discharge on the convective transport of phosphorus near the outfall is significantly reduced by a mid-river shoal area, which confines the flow path of the effluent to an embayment on the eastern side of the river for a distance of 4 kilometers below the outfall. This embayment appears to serve as a sediment trap, where protection from bottom scour during high-flow events has permitted fine-grained sediments to accumulate. Measurements of mean residence time indicate that the effluent leaves the embayment area 21? days after being discharged from the outfall. Measurements of the linear decay constant for the removal of dissolved phosphorus from the water column reveal a diurnal cycle corresponding to the metabolic utilization of phosphorus by phytoplankton. This cyclic removal is superimposed on a constant and noncyclic adsorption of phosphorus by inorganic phases. Forty-eight hour average values of the linear decay constant for dissolved phosphorus in the area range from 0.4 to 1.1 per day. Analyses of bottom sediments indicate that approximately 13 percent of the phosphorus discharged between September 1977 and August 1980 has been retained in the embayment. The primary inorganic phase responsible for phosphorus adsorption is amorphous iron (ferric oxy-hydroxides); amorphous aluminum and clay minerals appear to play

  4. Temperature, vegetation and precipitation variability in the Nile River drainage during the past 27,000 years: Insights from molecular and isotopic proxies

    NASA Astrophysics Data System (ADS)

    Castañeda, Isla; Schouten, Stefan; Pätzold, Jürgen; Schefuß, Enno

    2013-04-01

    The paleoclimate history of the Eastern Mediterranean (EM) region is of much interest due to its long history of human occupation. To date, much of our knowledge of past climate in the EM region comes from marine sedimentary records. These indicate that since the Last Glacial Maximum, major and sometimes abrupt sea surface temperature (SST) fluctuations occurred in response to global climate events including the Younger Dryas (YD), the Bølling-Allerød, and Heinrich Event 1 (H1). In comparison, less is known regarding continental paleoclimate conditions in this region due to a scarcity of well-dated continuous climate archives, particularly from Saharan North Africa. Here, we present new reconstructions of continental precipitation (plant leaf wax δD), C3 vs. C4 vegetation (plant leaf wax δ13C) and soil temperature (MBT/CBT paleothermometer) in the Nile River catchment in conjunction with previously published U37k' and TEX86SST reconstructions from the EM Sea. Our multiproxy records indicate that relative to the present, the LGM was characterized by arid conditions with cooler SST and soil temperatures in the catchment. The H1 event stands out as a major excursion in nearly all proxies and is characterized by an abrupt decrease in SST and the most arid conditions of the past 27,000 years. The African Humid Period (AHP) of the early Holocene is the wettest interval of the entire record and is observed from ~10,000 to 5,500 cal BP, with maximum wet conditions noted at ~8,000 cal BP. Interestingly, a rather abrupt cooling is noted in the MBT/CBT record at ~5.5 cal kyr, coinciding with the end of the AHP off west Africa; however, the transition out of the AHP is more gradual in the δD record. Overall both the continental and marine climate records indicate millennial scale climate variability. Our records also shed light on shifting sources of organic matter in response to the sequential cessation and re-initiation of different tributaries to the main flow of the

  5. Assessing habitat use by breeding great blue herons (Ardea herodias) on the upper Mississippi River, USA

    USGS Publications Warehouse

    Kirsch, E.M.; Ickes, B.; Olsen, D.A.

    2008-01-01

    Approximately 7,610 to 3,175 pairs of Great Blue Herons (Ardea herodias) nested along 420 river km of the Uppert Mississippi River (UMR) from 1993 to 2003. Numbers declined precipitously in the mid-1990s stabilizing somewhat in the early 2000s. The average number of nests in colonies was 349 (SD = 283). Annual colony turn over rate for the eleven year period was 0.15 and ranged from 0.06 to 0.29 each year. The number of years that a colony was active was positively correlated with the average number of nests present while the colony was active. Of the eight colonies active in 1993 that averaged more than 349 nests, four were abandoned by 2003. Only one colony grew to greater than 349 nests during the study period. Custer et al. (2004) suggested that herons on the UMR may be limited by forage resources or foraging habitat and social factors, as evidenced by the even spacing of colonies that reflects the maximum feeding range of herons on the river. To rule out nesting and foraging habitat limitation, landscape habitat features of terrestrial and aquatic areas were examined for colony areas and areas without colonies. Available fish monitoring data were used to examine potential interactions between herons and forage resources. Colony areas did not differ from areas without colonies in any habitat feature. Indices of potential heron forage fish increased from 1993 to 2002, although low indices of fish abundance in 1993 were likely influenced by flood conditions that year. Although fish availability to herons is related to flows and water levels, available data suggested that herons did not negatively impact their potential forage base. Numbers of herons were not correlated with indices of fish abundance from the preceding year on a pool-wide scale. Indices of fish abundance were higher within 5 km of colonies than farther than 5 km from colonies, and indices of fish abundance increased from June through August both near and far from colonies. Numbers of herons and

  6. The White Nile sedimentary system

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Resentini, Alberto; Vezzoli, Giovanni; Villa, Igor

    2014-05-01

    The Nile River flows for ~6700 km from south of the Equator to finally reach the Mediterranean Sea at northern subtropical latitudes (Woodward et al. 2007). This is the longest sedimentological laboratory on Earth, a unique setting in which we are investigating changes in sediment composition associated with diverse chemical and physical processes, including weathering and hydraulic sorting. The present study focuses on the southern branch of the Nile across 20° of latitude, from hyperhumid Burundi and Rwanda highlands in central Africa to Khartoum, the capital city of Sudan at the southern edge of the Sahara. Our study of the Kagera basin emphasizes the importance of weathering in soils at the source rather than during stepwise transport, and shows that the transformation of parent rocks into quartzose sand may be completed in one sedimentary cycle (Garzanti et al. 2013a). Micas and heavy minerals, less effectively diluted by recycling than main framework components, offer the best key to identify the original source-rock imprint. The different behaviour of chemical indices such as the CIA (a truer indicator of weathering) and the WIP (markedly affected by quartz dilution) helps us to distinguish strongly weathered first-cycle versus polycyclic quartz sands (Garzanti et al. 2013b). Because sediment is efficiently trapped in East African Rift lakes, the composition of Nile sediments changes repeatedly northwards across Uganda. Downstream of both Lake Kyoga and Lake Albert, quartzose sands are progressively enriched in metamorphiclastic detritus supplied from tributaries draining amphibolite-facies basements. The evolution of White Nile sediments across South Sudan, a scarcely accessible region that suffered decades of civil war, was inferred from the available information (Shukri 1950), integrated by original petrographic, heavy-mineral and geochemical data (Padoan et al. 2011). Mineralogical and isotopic signatures of Bahr-el-Jebel and Sobat sediments, derived

  7. Reproduction and early-age survival of manatees at Blue Spring, Upper St. Johns River, Florida

    USGS Publications Warehouse

    O'Shea, Thomas J.; Hartley, W.C.; O'Shea, Thomas J.; Ackerman, B.B.; Percival, H. Franklin

    1995-01-01

    We summarize reproduction of adults and survival of calves and subadult Florida manatees (Trichechus manatus latirostris) that were identified in winter at Blue Spring on the upper St. Johns River in Florida. Some records span more than 20 years, but most are from 15-year continuous annual observations during winter 1978-79 through winter 1992-93. Fifty-seven, first-year calves were identified; 55 litter sizes were one, and one consisted oftwins (1.79% of all births). Sex ratios of first-year calves did notsignificantly differfrom 1:1. Based on 21 of35 sighted females (15 individuals) that appeared pregnant and returned with calves during the subsequent winter, we estimated an early (neonatal to about 6 months) calf survival of 0.600. Based on estimations with a minimum-number-known-alive method, calf survival from the first to the second winter was at least 0.822, and subadult survival was 0.903 to the third, 0.958 to the fourth, 1.00 to the fifth, and 1.00 to the sixth winters. Seven females were observed from year of birth to their first winter with a nursing calf; the mean age at parturition to the first calf that survived to the next winter was 5.4 + 0.98 (SD) years. The estimated ages at first conception ranged from 3 to 6 years. The proportion of adult pregnant females was 0.410/year. Weaning was not observed in winter. Intervals between births averaged 2.60 + 0.81 years. The pooled proportion of adult females nursing first-winter calves was 0.303; the proportion of adult females nursing calves of any age was 0.407. These values do not significantly differ from those ofmanatees from the Crystal River or Atlantic Coast study areas. Anecdotal accounts are provided that suggested the existence of a pseudo estrus, an 11 to 13-month gestation, suppression of parturition in winter, and giving birth in quiet backwaters and canals. A female from Blue Spring produced at least seven calves during the 22 years since first observed and died giving birth at an estimated

  8. 21,000 years of Ethiopian African monsoon variability recorded in sediments of the western Nile deep-sea fan: impact of the Nile freshwater inflow for the Mediterranean thermo-haline circulation

    NASA Astrophysics Data System (ADS)

    Revel, Marie; Colin, Christophe; Bernasconi, Stephano; Combourieu-Nebout, Nathalie; Ducassou, Emmanuelle; Rolland, Yann; Bosch, Delphine

    2014-05-01

    The Nile delta sedimentation constitutes a continuous high resolution (1.6 mm/year) record of Ethiopian African monsoon regime intensity. Multiproxy analyses performed on core MS27PT recovered in hemipelagic Nile sediment margin (<90 km outward of the Rosetta mouth of the Nile) allow the quantification of the Saharan aeolian dust and the Blue/White Nile River suspended matter frequency fluctuations during the last 21 cal. ka BP. The radiogenic Sr and Nd isotopes, clay mineralogy, bulk elemental composition and palynological analyses reveal large changes in source components, oscillating between a dominant aeolian Saharan contribution during the LGM and the Late Holocene (~4 to 2 cal. ka BP), a dominant Blue/Atbara Nile River contribution during the early Holocene (15 to 8.4 cal. ka BP) and a probable White Nile River contribution during the Middle Holocene (8.4 to 4 cal. ka BP). The following main features are highlighted: 1. The rapid shift from the LGM arid conditions to the African Humid Period (AHP) started at about 15 cal. ka BP. AHP extends until 8.4 cal. ka BP, and we suggest that the Ethiopian African Monsoon maximum between 12 and 8 cal. ka BP is responsible for a larger Blue/Atbara Nile sediment load and freshwater input into the Eastern Mediterranean Sea. 2. The transition between the AHP and the arid Late Holocene is gradual and occurs in two main phases between 8.4 and 6.5 cal. ka BP and 6.5 to 3.2 cal. ka BP. We suggest that the main rain belt shifted southward from 8.4 to ~4 cal. ka BP and was responsible for progressively reduced sediment load and freshwater input into the eastern Mediterranean Sea. 3. The aridification along the Nile catchments occurred from ~4 to 2 cal. ka BP. A dry period, which culminates at 3.2 cal. ka BP, and seems to coincide with a re-establishment of increased oceanic primary productivity in the western Mediterranean Sea. We postulate that the decrease in thermo-haline water Mediterranean circulation could be part of a

  9. Flood-inundation mapping for the Blue River and selected tributaries in Kansas City, Missouri, and vicinity, 2012

    USGS Publications Warehouse

    Heimann, David C.; Weilert, Trina E.; Kelly, Brian P.; Studley, Seth E.

    2015-01-01

    The U.S. Geological Survey (USGS) and City of Kansas City, Missouri, operate multiple streamgages along the Blue River and tributaries in and near the city. Knowledge of water level at a streamgage is difficult to translate into depth and areal extent of flooding at points distant from the streamgage. One way to address these informational gaps is to produce a library of flood-inundation maps that are referenced to the stages recorded at a streamgage. By referring to the appropriate map, emergency responders can discern the severity of flooding (depth of water and areal extent), identify roads that are or may be flooded, and make plans for notification or evacuation of residents in harm’s way for some distance upstream and downstream from the streamgage. The USGS, in cooperation with the city of Kansas City, Missouri, developed a library of flood-inundation maps for the Blue River and selected tributaries.

  10. Nest initiation and clutch size of great blue herons on the Mississippi River in relation to the 1993 flood

    USGS Publications Warehouse

    Custer, T.W.; Hines, R.K.; Custer, Christine M.

    1996-01-01

    Great Blue Heron (Ardea herodias) eggs were collected from ten colonies between Clinton, Iowa and Royalton, Minnesota on the Mississippi River in 1993, a year of record floods in the midwestern United States. In the live southernmost colonies where record flooding occurred, Great Blue Herons initiated nesting two weeks later than herons nesting in the five northernmost colonies that were less affected by flooding. The southern nests had a-smaller average clutch size than the northern nests, but egg size was similar between south and north. Weather patterns in 1993 were similar between northern and southern colonies. We suspect that flooding of the available feeding habitat influenced nest initiation and clutch size. Data from 1995, a year without record flooding on the Mississippi River, support this hypothesis. In 1995, timing of nesting and number of eggs per clutch were similar between sites that had record flooding and sites that were less affected by flooding in 1993.

  11. Influence of spatial and temporal scales on statistical analyses of rainfall variability in the River Nile basin

    NASA Astrophysics Data System (ADS)

    Onyutha, Charles; Willems, Patrick

    2017-03-01

    In this study, empirical orthogonal function was applied to analyze rainfall variability in the Nile basin based on various spatio-temporal scales. The co-occurrence of rainfall variability and the variation in selected climate indices was analyzed based on various spatio-temporal scales. From the highest to the lowest, the cumulative amount of variance explained by the first two principal components (PCs) for any selected size of the spatial domain was obtained for the annual, seasonal, and monthly rainfall series respectively. The variability in the annual rainfall of 1° × 1° spatial coverage explained by only the first PC was about 55% on average. However, this percentage reduced to about 40% on average across the study area when the size of the spatial domain was increased from 1° × 1° to 10° × 10°. The variation in climate indices was shown to explain rainfall variability more suitably at a regional than location-specific spatial scale. The magnitudes and sometimes signs of the correlation between rainfall variability and the variation in climate indices tended to vary from one time scale to another. These findings are vital in the selection of spatial and temporal scales for more considered attribution of rainfall variability across the study area.

  12. Demographics and chronology of a spawning aggregation of blue sucker (Cycleptus elongatus) in the Grand River, Missouri, USA

    USGS Publications Warehouse

    Vokoun, Jason C.; Guerrant, Travis L.; Rabeni, Charles F.

    2003-01-01

    The blue sucker (Cycleptus elongatus) was sampled as individuals arrived, spawned, and departed from a spawning rime in the Grand River of northcentral Missouri, USA. The Grand River basin was not known to support blue sucker reproduction with few individuals ever recorded. The spawning site is unique in character for the lower river. Individuals began arriving in early April when water temperatures reached 10–12°C. Females with freely-flowing roe were sampled in late April after a large rise in river stage and concurrent lowering of the water temperature 4–5 degrees to 16.5°C. The spawning aggregation had a mean age of 15 y and ranged from 9 to 22 y based on scales that probably underestimated true ages. Males outnumbered females 5.5:1. Mean length was 659 mm for males and 721 mm for females. Females were longer at age than males and no significant age-length relationship was evident.

  13. Evaluation of High-Resolution Satellite Rainfall Products over the Nile Basin for Climatologic and Hydrologic Applications

    NASA Astrophysics Data System (ADS)

    Habib, E. H.; Haile, A.; Elsaadani, M.; Elshamy, M. E.; Amin, D.; Kuligowski, R. J.

    2010-12-01

    This study presents an evaluation of high-resolution rainfall estimates over the Nile Basin in Africa. The focus of the evaluation is two-fold: (1) can the satellite-rainfall products capture the overall climatological patterns and trends over the basin?, and (2) how and under what circumstances do these products support hydrologic predictions when being used as to drive a basin-wide hydrologic forecasting model? The products under examination are: the ‘Tropical Rainfall Measuring Mission (TRMM) and other sources’ (TRMM-3B42) product, and the National Oceanographic and Atmospheric Administration Climate Prediction Center (NOAA-CPC) product which is based on the CPC morphing technique (CMORPH). Over most parts of the Nile basin that are situated north of the equator, the CMORPH product shows a wet bias while the TRMM-3B42 product shows a dry bias. The estimates from both products were within the range of the climatologic records over parts of the basin around the equator. Both products reproduced the diurnal cycle of rain occurrence over the Lake Tana basin (the source of the Blue Nile) except over the mountains and the Lake shore. However, the TRMM-3B42 product underestimated the rainfall amounts in this basin. The satellite products captured the contrasting patterns of the diurnal cycles of rain occurrence and amount over the surroundings of Lake Victoria (the source of the White Nile). The second part of the evaluation focused on evaluating the possible improvements in streamflow predictions that are produced by the Nile Forecasting System (NFS) operated by the Nile Forecasting Center in Cairo, Egypt. The results suggest that that the performance of a basin-wide hydrologic model of the Nile river significantly improves when the CMORPH estimates serve as the main rainfall input compared to IR-based estimates traditionally used in the NFS model. In the Blue Nile basin, the relative volume error of the simulated flow decreased from -40 % when IR-based estimates

  14. Feeding ecology and energetic relationships with habitat of blue catfish, Ictalurus furcatus, and flathead catfish, Pylodictis olivaris, in the lower Mississippi River, U.S.A.

    USGS Publications Warehouse

    Eggleton, M.A.; Schramm, H.L.

    2004-01-01

    We examined feeding of blue catfish, Ictalurus furcatus, and flathead catfish, Pylodictis olivaris, collected from floodplain lake, secondary (side) river channel, and main river channel habitats in the lower Mississippi River (LMR), U.S.A. We described the feeding ecology of two large river catfish species within the context of whether off-channel habitats in the LMR (i.e., floodplain lakes and secondary channels) potentially provided energetic benefits to these fishes as purported in contemporary theory on the ecology of large rivers. We used diet composition and associated caloric densities of prey consumed as indicators of energetic benefit to catfishes. Differences in diet among habitats were strong for blue catfish, but weak for flathead catfish; consumed foods generally differed among habitats in caloric (energy) content. Caloric densities of consumed foods were generally greatest in floodplain lakes, least in the main river channel, and intermediate in secondary river channels. Strong between-year variation in diet was observed, but only for blue catfish. Blue catfish fed disproportionately on lower-energy zebra mussels in the main river channel during 1997, and higher-energy chironomids and oligochaetes in floodplain lakes during 1998. Results suggested that although off-channel habitats potentially provided greater energetic return to catfishes in terms of foods consumed, patterns of feeding and subsequent energy intake may vary annually. Energetic benefits associated with off-channel habitats as purported under contemporary theory (e.g., the 'flood-pulse concept') may not be accrued by catfishes every year in the LMR.

  15. Occurrence of cyanobacteria and microcystin toxins in raw and treated waters of the Nile River, Egypt: implication for water treatment and human health.

    PubMed

    Mohamed, Zakaria A; Deyab, Mohamed Ali; Abou-Dobara, Mohamed I; El-Sayed, Ahmad K; El-Raghi, Wesam M

    2015-08-01

    Monitoring of cyanobacteria and their associated toxins has intensified in raw water sources of drinking water treatment plants (WTPs) in most countries of the world. However, it is not explored yet for Egyptian WTPs. Therefore, this study was undertaken to investigate the occurrence of cyanobacteria and their microcystin (MC) toxins in the Nile River source water of Damietta WTP during warm months (April-September 2013) and to evaluate the removal efficiency of both cyanobacterial cells and MCs by conventional methods used in this plant as a representative of Egyptian drinking WTPs. The results showed that the source water at the intake of Damietta WTP contained dense cyanobacterial population (1.1-6.6 × 107 cells L(-1)) dominated by Microcystis aeruginosa. This bloom was found to produce MC-RR and MC-LR. Both cyanobacterial cell density and intracellular MCs in the intake source water increased with the increase in temperature and nutrients during the study period, with maximum values obtained in August. During treatment processes, cyanobacterial cells were incompletely removed by coagulation/flocculation/sedimentation (C/F/S; 91-96.8%) or sand filtration (93.3-98.9%). Coagulation/flocculation induced the release of MCs into the ambient water, and the toxins were not completely removed or degraded during further treatment stages (filtration and chlorination). MCs in outflow tank water were detected in high concentrations (1.1-3.6 μg L - 1), exceeding WHO provisional guideline value of 1 μg L - 1 for MC-LR in drinking water. Based on this study, regular monitoring of cyanobacteria and their cyanotoxins in the intake source water and at different stages at all WTPs is necessary to provide safe drinking water to consumers or to prevent exposure of consumers to hazardous cyanobacterial metabolites.

  16. West Nile virus

    MedlinePlus

    ... believe West Nile virus is spread when a mosquito bites an infected bird and then bites a ... avoid getting West Nile virus infection after a mosquito bite. People in good health generally do not ...

  17. Metal concentrations, foraging distances, and fledging success of great blue herons nesting along the Hanford Reach of the Columbia River.

    PubMed

    Tiller, Brett L; Marco, J D; Rickard, W H

    2005-05-01

    An ecological risk assessment of the spatial distribution of metal concentrations along the Hanford Reach of the free-flowing Columbia River in southcentral Washington, identified great blue herons, Ardea herodias, at potential risk through the ingestion of contaminated riverine biota, especially fish. We measured metal concentrations in livers of pre-flight herons from the Hanford Reach and excrement samples taken from the same nests. Nests were distributed among three colonies situated upstream and downstream from nine retired plutonium production reactors along the river where metals in reactor coolant waters had been released directly into the river or disposed to shoreline retention basins and ditches. Distances traveled by parent herons to foraging areas along the river shore were determined by visually tracking parent birds as they flew from nests to upriver and downriver foraging sites. Foraging flight distances varied between colonies with mean distances ranging between 0.7 and 3.1 km. Cadmium, Cr, and Pb concentrations were higher in excrement than in the livers of pre-flight herons but the opposite was noted for Cu, Hg, and Zn. Highest metal concentrations of Cr, Cu, Zn, Cd, and Pb, were measured in excrement taken from heron nests at the colony located upstream from all reactors. These results were consistent with metal concentrations reported in river sediment from the same regions, indicating excrement from the heron nests may be a useful indicator of dietary uptake of metals by herons. Fledging success and eggshell thickness measurements were used as an index of health of the local heron population. The results indicate that the reproductive health of great blue herons nesting along the Hanford Reach is among the highest reported in the continental United States.

  18. Estimation of survival of adult Florida manatees in the Crystal River, at Blue Spring, and on the Atlantic Coast

    USGS Publications Warehouse

    O'Shea, Thomas J.; Langtimm, Catherine A.; O'Shea, Thomas J.; Ackerman, B.B.; Percival, H. Franklin

    1995-01-01

    We applied Cormack-Jolly-Seber open population models to manatee (Trichechus manatus latirostris) photo-identification databases to estimate adult survival probabilities. The computer programs JOLLY and RECAPCO were used to estimate survival of 677 individuals in three study areas: Crystal River (winters 1977-78 to 1990-91), Blue Spring (winters 1977-78 to 1990-91), and the Atlantic Coast (winters 1984-85 to 1990-91). We also estimated annual survival from observations of 111 manatees tagged for studies with radiotelemetry. Survival estimated from observations with telemetry had broader confidence intervals than survival estimated with the Cormack-Jolly-Seber models. Annual probabilities of capture based on photo-identification records were generally high. The mean annual adult survival estimated from sighting-resighting records was 0.959-0.962 in the Crystal River and 0.936-0.948 at Blue Spring and may be high enough to permit population growth, given the values of other life-history parameters. On the Atlantic Coast, the estimated annual adult survival (range of means = 0.877-0.885) may signify a declining population. However, for several reasons, interpretation of data from the latter study group should be tempered with caution. Adult survivorship seems to be constant with age in all three study groups. No strong differences were apparent between adult survival ofmales and females in the Crystal River or at Blue Spring; the basis of significant differences between sexes on the Atlantic Coast is unclear. Future research into estimating survival with photo-identification and the Cormack-Jolly-Seber models should be vigorously pursued. Estimates of annual survival can provide an additional indication of Florida manatee population status with a stronger statistical basis than aerial counts and carcass totals.

  19. Physical characteristics of stream subbasins in the Blue Earth River Basin, south-central Minnesota and north-central Iowa

    USGS Publications Warehouse

    Lorenz, D.L.; Payne, G.A.

    1992-01-01

    This report presents data describing the physical characteristics of stream basins upstream from selected points on streams in the Blue Earth River basin, located in south-central Minnesota and north-central Iowa. The physical characteristics are the drainage area of the basin, the percentage area of the basin covered only by lakes, the percentage area of the basin covered by both lakes and wetlands, the main-channel length, and the mainchannel slope. The points on the stream include outlets of subbasins of at least five square miles, outfalls of sewage treatment plants, and locations of U.S. Geological Survey gaging stations.

  20. Responses of macroinvertebrate community metrics to a wastewater discharge in the Upper Blue River of Kansas and Missouri, USA

    USGS Publications Warehouse

    Poulton, Barry C.; Graham, Jennifer; Rasmussen, Teresa J.; Stone, Mandy L.

    2015-01-01

    The Blue River Main wastewater treatment facility (WWTF) discharges into the upper Blue River (725 km2), and is recently upgraded to implement biological nutrient removal. We measured biotic condition upstream and downstream of the discharge utilizing the macroinvertebrate protocol developed for Kansas streams. We examined responses of 34 metrics to determine the best indicators for discriminating site differences and for predicting biological condition. Significant differences between sites upstream and downstream of the discharge were identified for 15 metrics in April and 12 metrics in August. Upstream biotic condition scores were significantly greater than scores at both downstream sites in April (p = 0.02), and in August the most downstream site was classified as non-biologically supporting. Thirteen EPT taxa (Ephemeroptera, Plecoptera, Trichoptera) considered intolerant of degraded stream quality were absent at one or both downstream sites. Increases in tolerance metrics and filtering macroinvertebrates, and a decline in ratio of scrapers to filterers all indicated effects of increased nutrient enrichment. Stepwise regressions identified several significant models containing a suite of metrics with low redundancy (R2 = 0.90 - 0.99). Based on the rapid decline in biological condition downstream of the discharge, the level of nutrient removal resulting from the facility upgrade (10% - 20%) was not enough to mitigate negative effects on macroinvertebrate communities.

  1. Responses of macroinvertebrate community metrics to a wastewater discharge in the Upper Blue River of Kansas and Missouri, USA

    USGS Publications Warehouse

    Poulton, Barry C.; Graham, Jennifer; Rasmussen, Teresa J.; Stone, Mandy L.

    2015-01-01

    The Blue River Main wastewater treatment facility (WWTF) discharges into the upper Blue River (725 km2), and is recently upgraded to implement biological nutrient removal. We measured biotic condition upstream and downstream of the discharge utilizing the macroinvertebrate protocol developed for Kansas streams. We examined responses of 34 metrics to determine the best indicators for discriminating site differences and for predicting biological condition. Significant differences between sites upstream and downstream of the discharge were identified for 15 metrics in April and 12 metrics in August. Upstream biotic condition scores were significantly greater than scores at both downstream sites in April (p = 0.02), and in August the most downstream site was classified as non-biologically supporting. Thirteen EPT taxa (Ephemeroptera, Plecoptera, Trichoptera) considered intolerant of degraded stream quality were absent at one or both downstream sites. Increases in tolerance metrics and filtering macroinvertebrates, and a decline in ratio of scrapers to filterers all indicated effects of increased nutrient enrichment. Stepwise regressions identified several significant models containing a suite of metrics with low redundancy (R2 = 0.90 - 0.99). Based on the rapid decline in biological condition downstream of the discharge, the level of nutrient removal resulting from the facility upgrade (10% - 20%) was not enough to mitigate negative effects on macroinvertebrate communities.

  2. Twelve myxosporean species of the family Myxobolidae infecting freshwater fishes of the River Nile, Egypt, with the description of four novel species.

    PubMed

    Abdel-Ghaffar, Fathy; Morsy, Kareem; El-Ganainy, Sahar; Ahmed, Manal; Gamal, Shams; Bashtar, Abdel-Rahman; Al Quraishy, Saleh; Mehlhorn, Heinz

    2015-08-01

    Myxosporidian parasites infecting fish are very dangerous parasites causing severe damage to a large number of economically important fishes especially in aquaculture. A survey of myxosporean parasites infecting four species of fishes from the River Nile in Egypt is conducted. One hundred and ninety-five out of 316 fish specimens with a percentage of 61.7% were found to be naturally infected with these parasites. Light microscopic examination of different tissues revealed the presence of 12 myxosporean species belonging to the family Myxobolidae. Four of the identified species are novel and the other eight species are redescribed. Myxidium sp.nov. a coelozoic species inhabiting the gallbladder of Labeo niloticus with its mature spores float free in bile was detected. These spores possess a fusiform, straight, or slightly crescentic shape with less pointed ends and two equal polar capsules. Three novel histozoic Myxobolus species infecting Oreochromis niloticus were identified. Myxobolus sp(1).nov. is a species inhabiting kidney tissue with ovoid spores exhibiting a small intercapsular appendix. Myxobolus sp(2).nov. and Myxobolus sp(3).nov. recovered from kidney and intestinal tissues. Spores of Myxobolus sp(2).nov. are elliptical in shape with an anterior end wider than posterior one. Their two polar capsules are ovoid to pyriform occupied nearly the first third of the spore body. Spores of Myxobolus sp(3).nov. are broader than long with nearly rounded or ovoid two polar capsules. Eight species of the recovered myxosporean parasites are redescribed, Myxobolus niloticus Fahmy et al., 1971 from pectoral, dorsal, and tail fins of L. niloticus, Henneguya suprabranchiae Landsberg, 1987, and Henneguya branchialis Ashmawy et al., 1989 are recovered from the gills and suprabranchial organ of the catfish Clarias gariepinus, respectively, Myxobolus naffari Abdel-Ghaffar et al., 1998 and Myxobolus imami Ali et al., 2002 are found in the kidney of Barbus bynni and L. niloticus

  3. Geological evolution and incision history of the Gorge of the Nile on Ethiopian Plateau from remote sensing and geographic information system analysis, and field studies

    NASA Astrophysics Data System (ADS)

    Gani, Nahid Ds

    Integrated remote sensing and Geographic System Analysis (GIS) analysis has proven to be an effective approach in geological studies of vast, inaccessible areas with dispersed field information. Such an approach has been undertaken to study the 1.6 km deep Gorge of the Nile formed by the Blue Nile, situated on the Northwestern Ethiopian Plateau. The analysis of Digital Elevation Models (DEMs) extracted from the Shuttle Radar Topography Mission (SRTM) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) for river geomorphic information shows a dramatic decrease in average gradient and an increase in valley width, depth and asymmetry from headwater to downstream along the Gorge of the Nile. The integration of orbital-optical and radar remote sensing data including ASTER, Landsat Thematic Mapper (TM), RADARSAT, and DEMs with field data to trace lithological units and structural features of the study area has helped in delineating geologic history of the area as well as the geologic controls on the formation of the Gorge of the Nile. This study has revealed that the Blue Nile Basin evolved in three main phases: (1) Pre-sedimentation phase involving pre-rift peneplanation of the Neoproterozoic basement rocks; (2) Post-rift, Mesozoic sedimentation with repeated marine transgressions and regressions, including fluvial sandstones, and marine limestone and glauconitic mudstones; (3) Post-sedimentation phase which involve extensive volcanism from Middle Oligocene to Quaternary related to the Afar mantle plume. These stratigraphic units are deformed by normal faults of NW and NE-trends with a series of horsts and grabens that are thought to be formed by polyphase deformation and/or stress compartmentalization, indicating that the Blue Nile Basin is located within an extensional regime. Analysis of DEMs with GIS has been used to study the timing, pattern, depth and rate of incision in the evolution of the Gorge of the Nile as well as the Blue Nile

  4. Feeding habitat characteristics of the great blue heron and great egret nesting along the Upper Mississippi River, 1995-1998

    USGS Publications Warehouse

    Custer, Christine M.; Suarez, S.A.; Olsen, D.A.

    2004-01-01

    The Great Blue Heron (Ardea herodias) and Great Egret (Ardea alba) nested in eight colonies along the Upper Mississippi River, USA, and individual birds were followed by airplane to feeding sites during the nesting seasons in 1995-1998. Both species used braided channel/backwater habitats for feeding more than expected, based on availability, and open pool and main navigation channel less than expected. Most individuals of both species fed 10 km away. Habitat and distance need to be considered simultaneously when assessing habitat quality for herons and egrets. The Great Blue Heron flew farther to feeding sites during the care-of-young period than during incubation and the Great Egret showed the opposite pattern. The Great Blue Heron tended to feed solitarily; only 10% of the feeding flights ended at a location where another heron was already present. About one-third of Great Egret feeding flights ended at a location with another egret already present. Colony placement on the landscape seemed to be a function of the feeding radius of each colony.

  5. β-carotene and retinoids in eggs of Great Blue Herons (Ardea herodias) in relation to St Lawrence River contamination.

    PubMed

    Boily, M H; Champoux, L; Bourbonnais, D H; Des Granges, J L; Rodrigue, J; Spear, P A

    1994-12-01

    : The potential use of retinoids and β-carotene as biomarkers in the eggs of the Great Blue Heron was investigated. In the spring of 1991, 65 eggs were collected from nine heronries (seven along the St Lawrence River and two reference sites). A method was specifically developed for the extraction and analysis of β-carotene and the retinoids in heron egg yolks by reversed-phase HPLC. When results were expressed either as the molar ratio of retinol: retinyl palmitate or as retinyl palmitate concentration, significant differences were found between colonies; however, retinyl palmitate concentration was deemed the better biomarker because it was not significantly influenced by embryonic stage of development. Retinyl palmitate concentrations in freshwater colonies were negatively related to PCB congeners Nos 105 and 118 as well as their TCDD-EQ values (p < 0.02, r (2)=0.78). Egg tetrachloro-mono-ortho biphenyl concentrations were also negatively related to retinyl palmitate (p < 0.005, r (2)=0.90). With the exception of the two mono-ortho co-planar congeners detected in the present study, the contamination levels found in heron eggs were well below those found for other bird species in the Great Lakes area and, so far, no detrimental effects have been reported in Great Blue Heron populations in Quebec. These results suggest that retinyl palmitate may be useful as a sensitive and non-invasive biomarker for monitoring organochlorine contaminant effects in the Great Blue Heron in freshwater sites.

  6. Separation and Preconcentration of Sudan Blue II Using Membrane Filtration and UV-Visible Spectrophotometric Determination in River Water and Industrial Wastewater Samples.

    PubMed

    Unsal, Yunus Emre; Tuzen, Mustafa; Soylak, Mustafa

    2015-01-01

    A new separation and preconcentration method based on adsorption on a cellulose acetate membrane filter and elution with ethanol was established for the UV-Vis spectrophotometric determination of Sudan blue II. Various analytical parameters such as pH of working media, flow rates of solutions, and sample volumes were optimized. Matrix effects of concomitants were investigated for the quantitative recovery values of Sudan blue II. The preconcentration factor was 200. LOD was calculated as 0.96 μg/L. RSD was 5.1%. The optimized procedure was applied to the spectrophotometric determination of Sudan blue II in river and industrial wastewater samples from oil and dye products.

  7. Blue tilapia (Oreochromis aureus) predation on fishes in the Muddy River system, Clark County, Nevada

    USGS Publications Warehouse

    Scoppettone, G.G.; Salgado, J.A.; Nielsen, M.B.

    2005-01-01

    Blue tilapia (Oreochromis aureus), native to North Africa and the Middle East (Courtenay and Robins 1973, Fuller et al. 1999), has been introduced around the world as a human food source, for vegetation control, and as a game fish (Costa-Pierce and Riedel 2000). Blue tilapia has been particularly successful in establishing and spreading in North American waters where it has been reported to change fish community structure and cause native fish decline (Courtenay and Robins 1973, Fuller et al. 1999). Because of these detrimental effects, it is now generally considered an unwelcome introduction into North American waters (Dill and Cordone 1997, Fuller et al. 1999).

  8. Liquefaction potential of Nile delta, Egypt

    NASA Astrophysics Data System (ADS)

    Fergany, Elsayed; Omar, Khaled

    2017-06-01

    Understanding how sedimentary basins respond to seismic-wave energy generated by earthquake events is a significant concern for seismic-hazard estimation and risk analysis. The main goal of this study is assessing the vulnerability index, Kg, as an indicator for liquefaction potential sites in the Nile delta basin based on the microtremor measurements. Horizontal to Vertical spectral ratio analyses (HVSR) of ambient noise data, which was conducted in 2006 at 120 sites covering the Nile delta from south to north were reprocessed using Geopsy software. HVSR factors of amplification, A, and fundamental frequency, F, were calculated and Kg was estimated for each measurement. The Kg value varies widely from south toward north delta and the potential liquefaction places were estimated. The higher vulnerability indices are associated with sites located in southern part of the Nile delta and close to the branches of Nile River. The HVSR factors were correlated with geologic setting of the Nile delta and show good correlations with the sediment thickness and subsurface stratigraphic boundaries. However, we note that sites located in areas that have greatest percentage of sand also yielded relatively high Kg values with respect to sites in areas where clay is abundant. We concluded that any earthquake with ground acceleration more than 50 gal at hard rock can cause a perceived deformation of sandy sediments and liquefaction can take place in the weak zones of Kg ≥ 20. The worst potential liquefaction zones (Kg > 30) are frequently joined to the Damietta and Rosetta Nile River branches and south Delta where relatively coarser sand exists. The HVSR technique is a very sensitive tool for lithological stratigraphy variations in two dimensions and varying liquefaction susceptibility.

  9. Inter- and intra-annual variation of water footprint of crops and blue water scarcity in the Yellow River basin (1961-2009)

    NASA Astrophysics Data System (ADS)

    Zhuo, La; Mekonnen, Mesfin M.; Hoekstra, Arjen Y.; Wada, Yoshihide

    2016-01-01

    The Yellow River Basin (YRB), the second largest river basin of China, has experienced a booming agriculture over the past decades. But data on variability of and trends in water consumption, pollution and scarcity in the YRB are lacking. We estimate, for the first time, the inter- and intra-annual water footprint (WF) of crop production in the YRB for the period 1961-2009 and the variation of monthly scarcity of blue water (ground and surface water) for 1978-2009, by comparing the blue WF of agriculture, industry and households in the basin to the maximum sustainable level. Results show that the average overall green (from rainfall) and blue (from irrigation) WFs of crops in the period 2001-2009 were 14% and 37% larger, respectively, than in the period 1961-1970. The annual nitrogen- and phosphorus-related grey WFs (water required to assimilate pollutants) of crop production grew by factors of 24 and 36, respectively. The green-blue WF per ton of crop reduced significantly due to improved crop yields, while the grey WF increased because of the growing application of fertilizers. The ratio of blue to green WF increased during the study period resulting from the expansion of irrigated agriculture. In the period 1978-2009, the annual total blue WFs related to agriculture, industry and households varied between 19% and 52% of the basin's natural runoff. The blue WF in the YRB generally peaks around May-July, two months earlier than natural peak runoff. On average, the YRB faced moderate to severe blue water scarcity during seven months (January-July) per year. Even in the wettest month in a wet year, about half of the area of the YRB still suffered severe blue water scarcity, especially in the basin's northern part.

  10. Water-quality assessment of the largely urban blue river basin, Metropolitan Kansas City, USA, 1998 to 2007

    USGS Publications Warehouse

    Wilkison, D.H.; Armstrong, D.J.; Hampton, S.A.

    2009-01-01

    From 1998 through 2007, over 750 surface-water or bed-sediment samples in the Blue River Basin - a largely urban basin in metropolitan Kansas City - were analyzed for more than 100 anthropogenic compounds. Compounds analyzed included nutrients, fecal-indicator bacteria, suspended sediment, pharmaceuticals and personal care products. Non-point source runoff, hydrologic alterations, and numerous waste-water discharge points resulted in the routine detection of complex mixtures of anthropogenic compounds in samples from basin stream sites. Temporal and spatial variations in concentrations and loads of nutrients, pharmaceuticals, and organic wastewater compounds were observed, primarily related to a site's proximity to point-source discharges and stream-flow dynamics. ?? 2009 ASCE.

  11. Observations on the Nesting Distribution of Great Blue Herons on the Hanford Reach of the Columbia River

    SciTech Connect

    Rickard, William H.; Tiller, Brett L.

    2003-10-01

    Great blue herons probably did not nest along the Hanford Reach of the Columbia River in the 1800s because of the scarcity of trees. Trees were first introduced to land along the Reach with the advent of irrigation farming in the early 1900s. Since 1950 most of the heron colonies distributed along the Hanford Reach have elected to nest in clusters of non-native trees planted 80 to 100 years ago at scattered farmhouse locations. These sites have been protected from most human intrusions by the safety and security provisions enforced by the U.S. Department of Energy's Hanford Site since 1943. Reproductive success of Hanford Reach colonies is equal to or better than that of heron colonies elsewhere in the Pacific Northwest. In recent years the number of active heron colonies along the reach has declined. The causes of the observed decline are unknown to us.

  12. Public acceptance of disturbance-based forest management: a study of the Blue River Landscape Strategy in the Central Cascades Adaptive Management Area.

    Treesearch

    Bruce Shindler; Angela L. Mallon

    2009-01-01

    This report examines public perspectives on disturbance-based management conducted in the central Cascade Range in Oregon as part of the Blue River Landscape Strategy. A mail survey to local residents was used to describe the public’s understanding of this form of management, identify perceived associated risks and potential barriers to implementation, and the overall...

  13. Perfluorinated Compounds and Polybrominated Diphenyl Ethers in Great Blue Heron Eggs from Three Colonies on the Mississippi River, Minnesota

    USGS Publications Warehouse

    Custer, T.W.; Kannan, K.; Tao, L.; Yun, S.-H.; Trowbridge, A.

    2010-01-01

    Archived Great Blue Heron (Ardea herodias) eggs (N = 16) collected in 1993 from three colonies on the Mississippi River in Minnesota were analyzed in 2007 for perfluorinated compounds (PFCs) and polybrominated diphenyl ethers (PBDEs). One of the three colonies, Pig's Eye, was located near a presumed source of PFCs. Based on a multivariate analysis, the pattern of nine PFC concentrations differed significantly between Pig's Eye and the upriver (P = 0.002) and downriver (P = 0.02) colonies; but not between the upriver and downriver colonies (P = 0.25). Mean concentrations of perfluorooctane sulfonate (PFOS), a major PFC compound, were significantly higher at the Pig's Eye colony (geometric mean = 940 ng/g wet weight) than at upriver (60 ng/g wet weight) and downriver (131 ng/g wet weight) colonies. Perfluorooctane sulfonate concentrations from the Pig's Eye colony are among the highest reported in bird eggs. Concentrations of PFOS in Great Blue Heron eggs from Pig's Eye were well below the toxicity thresholds estimated for Bobwhite Quail (Colinus virginianus) and Mallards (Anas platyrhynchos), but within the toxicity threshold estimated for White Leghorn Chickens (Gallus domesticus). The pattern of six PBDE congener concentrations did not differ among the three colonies (P = 0.08). Total PBDE concentrations, however, were significantly greater (P = 0.03) at Pig's Eye (geometric mean = 142 ng/g wet weight) than the upriver colony (13 ng/g wet weight). Polybrominated diphenyl ether concentrations in two of six Great Blue Heron eggs from the Pig's Eye colony were within levels associated with altered reproductive behavior in American Kestrels (Falco sparverius).

  14. Ecological risk assessment in a large river-reservoir. 7: Environmental contaminant accumulation and effects in great blue heron

    SciTech Connect

    Halbrook, R.S.; Brewer, R.L. Jr.; Buehler, D.A.

    1999-04-01

    Past plant operations and waste disposal on the Oak Ridge Reservation (ORR) have introduced an assortment of potentially harmful contaminants into the surrounding environment. Elevated concentrations of mercury (Hg) and PCBs have been found in fish collected from aquatic systems on the ORR, and a screening level risk assessment has identified piscivorous wildlife downstream from the ORR as being at risk. As a component of an ecological risk assessment of a large river-reservoir system, the great blue heron (Ardea herodias) was chosen as an endpoint species to evaluate potential adverse effects of contaminants on piscivorous wildlife using aquatic systems on or downstream of the ORR. Eggs and chick liver, muscle, and fat samples were collected from two heron colonies located on and two colonies located off the ORR. Samples were analyzed for PCBs, mercury, chromium, and arsenic to determine if differences existed among colonies. Mean mercury and PCB concentrations were greater in eggs and chick tissues collected from colonies located on the ORR. However, no biologically significant differences were observed in fecundity or in egg physical measurements or chick physiological measurements between study locations. The results of this study do not indicate that the contaminant burdens in great blue heron chicks and eggs have a detrimental effect on heron populations utilizing aquatic habitats on the ORR.

  15. Environmental contaminants in great blue herons (Ardea herodias) from the lower Columbia and Willamette Rivers, Oregon and Washington, USA

    SciTech Connect

    Thomas, C.M.; Anthony, R.G.

    1999-12-01

    Great blue heron (Ardea herodias) eggs and prey items were collected from six colonies in Oregon and Washington, USA, during 1994 to 1995. Contaminant concentrations, reproductive success, and biomagnification factors were determined and effects of residue levels were measured by H4IIE rat hepatoma bioassays. Mean residue concentrations in heron eggs and prey items were generally low. However, elevated concentrations of polychlorinated biphenyls (PCBs) were detected in eggs and prey from Ross Island on the Willamette River. Biomagnification factors varied among sites. Sites were not significantly different in H4IIE tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQs), although the TCDD-EQ for Karlson Island was 9 to 20 times greater than that of any other site. Large differences existed between toxic equivalents calculated from egg residue concentrations and TCDD-EQs, which indicated nonadditive interactions among the compounds. Tetrachlorodibenzo-p-dioxin equivalents and nest failure were positively correlated with TCDD concentration. Fledging and reproductive rates were similar to those determined for healthy heron populations, however, indicating that any adverse effects were occurring at the individual level and not at the colony level. Their results support the use of great blue herons as a biomonitor for contamination in aquatic ecosystems. Their relatively low sensitivity to organochlorine contaminants and high trophic position allows contaminant accumulation and biomagnification without immediate adverse effects that are often seen in other, more sensitive species.

  16. Character and Trends of Water Quality in the Blue River Basin, Kansas City Metropolitan Area, Missouri and Kansas, 1998 through 2007

    USGS Publications Warehouse

    Wilkison, Donald H.; Armstrong, Daniel J.; Hampton, Sarah A.

    2009-01-01

    Water-quality and ecological character and trends in the metropolitan Blue River Basin were evaluated from 1998 through 2007 to provide spatial and temporal resolution to factors that affect the quality of water and biota in the basin and provide a basis for assessing the efficacy of long-term combined sewer control and basin management plans. Assessments included measurements of stream discharge, pH, dissolved oxygen, specific conductance, turbidity, nutrients (dissolved and total nitrogen and phosphorus species), fecal-indicator bacteria (Escherichia coli and fecal coliform), suspended sediment, organic wastewater and pharmaceutical compounds, and sources of these compounds as well as the quality of stream biota in the basin. Because of the nature and myriad of factors that affect basin water quality, multiple strategies are needed to decrease constituent loads in streams. Strategies designed to decrease or eliminate combined sewer overflows (CSOs) would substantially reduce the annual loads of nutrients and fecal-indicator bacteria in Brush Creek, but have little effect on Blue River loadings. Nonpoint source reductions to Brush Creek could potentially have an equivalent, if not greater, effect on water quality than would CSO reductions. Nonpoint source reductions could also substantially decrease annual nutrient and bacteria loadings to the Blue River and Indian Creek. Methods designed to decrease nutrient loads originating from Blue River and Indian Creek wastewater treatment plants (WWTPs) could substantially reduce the overall nutrient load in these streams. For the main stem of the Blue River and Indian Creek, primary sources of nutrients were nonpoint source runoff and WWTPs discharges; however, the relative contribution of each source varied depending on how wet or dry the year was and the number of upstream WWTPs. On Brush Creek, approximately two-thirds of the nutrients originated from nonpoint sources and the remainder from CSOs. Nutrient assimilation

  17. Anthropic signatures in alluvium of the Upper Little Tennessee River valley, Southern Blue Ridge Mountains, USA

    Treesearch

    Lixin Wang; David S. Leigh

    2015-01-01

    Human activities have become important influences on the fluvial systems of eastern North America since post-colonial settlement. This research identifies post-settlement anthropic signatures in alluvial sediments in the Upper Little Tennessee River, USA. Agricultural and mining activities were scattered and discontinuous in this relatively remote region of...

  18. [West Nile fever].

    PubMed

    Takasaki, Tomohiko

    2005-12-01

    West Nile virus was first detected in North America in 1999 and has spread throughout the United States and Canada and into Mexico and the Caribbean. The cases of encephalitis in New York were diagnosed as Saint Louis encephalitis which was endemic in the North America. However, dead crows and dead flamingo were found around the same time in New York. American birds seldom die by Saint Louis encephalitis virus infection. According to viral isolation and sequencing of the genome, the causative agent of unknown encephalitis was West Nile virus which was a member of Flaviviridae which cause fever, meningitis and encephalitis. West Nile virus is still active in North America in summer season, 1999 -2005. CDC enlightens people how to protect themselves and their community from West Nile virus. There are some reports that West Nile viral infections were occurred by blood transfusion, biologic products from blood and organ transfusion.

  19. Late Quaternary environments and prehistoric occupation in the lower White Nile valley, central Sudan

    NASA Astrophysics Data System (ADS)

    Williams, Martin A. J.; Usai, Donatella; Salvatori, Sandro; Williams, Frances M.; Zerboni, Andrea; Maritan, Lara; Linseele, Veerle

    2015-12-01

    Despite the major contributions provided over fifty years ago by A.J. Arkell and J.D. Tothill to our understanding of late Quaternary environments and prehistoric occupation near the confluence of the Blue and White Nile in central Sudan, three key questions have remained unresolved since then. (a) Was the decline in Nile flood levels from early Holocene times onwards caused by a reduction in Nile discharge, or by channel incision, or both? (b) Was the regional climate wetter during times of high Nile floods and drier during times of low Nile floods? (c) Given the high degree of disturbance of Mesolithic and later prehistoric sites, is it possible to identify primary-context, stratified and undisturbed occupation? Drawing upon dated evidence from three sites to the east of and three to the west of the lower White Nile, we provide a qualified answer to the first question and documented affirmative answers to the second and third questions.

  20. Nile behaviour and Upper Palaeolithic humans in Upper Egypt

    NASA Astrophysics Data System (ADS)

    Vermeersch, Pierre M.

    2014-05-01

    There is evidence of a decreasing human occupation of the Upper Egyptian Nile valley during the MIS 5 to MIS 3 period. Whereas very large extraction sites of the Middle Stone Age have been recorded, only very few sites of the Upper Palaeolithic have been found. The best explanation of this fact is that during the Late Middle Stone Age and the Upper Palaeolithc there was nearly no need for raw materials because there was only a very restricted population present in Upper Egypt. From about 22 ka BP an important population increase is registered by the presence of numerous Late Palaeolithic sites. During the whole LGM there is abundant presence of humans along the Nile Valley in Upper Egypt. This population was mainly living from fishing. There seems to be an abrupt end of the Palaeolithic occupation after 12.8 ka BP. Until now, no sites were found in the Valley until some rare Epipaleolithic sites occur about 8.0 ka BP. It will be suggested that these population changes are influenced by the river Nile behaviour. The best interpretation of the observations in the Upper Egyptian Nile Valley is the hypothesis that at the same time that Nile flow was reduced because of the dryness in its source area, the impact of aeolian activity was increased over Northeast Africa. The increased aeolian activity by northern winds in the Fayum and Wadi Ryan during the LGM resulted in the accumulation of aeolian sand in the valley. That aeolian sand was transported along the western Nile valley cliffs until it was accumulated when the Nile Valley change it S-N direction, such as at Nag'Hammadi. At other places sand was invading the Nile valley, directly from the Western Desert, creating a damming of the Nile at several places such as Armant and Aswan. As Nile flow was quite reduced, the Nile was unable to erode all the incoming sand and the Nile water with its important clay content was dammed. At several places large lakes were created in the Nile Valley. Those lakes were an ideal

  1. Estimated Flood-Inundation Mapping for the Upper Blue River, Indian Creek, and Dyke Branch in Kansas City, Missouri, 2006-08

    USGS Publications Warehouse

    Kelly, Brian P.; Huizinga, Richard J.

    2008-01-01

    In the interest of improved public safety during flooding, the U.S. Geological Survey, in cooperation with the city of Kansas City, Missouri, completed a flood-inundation study of the Blue River in Kansas City, Missouri, from the U.S. Geological Survey streamflow gage at Kenneth Road to 63rd Street, of Indian Creek from the Kansas-Missouri border to its mouth, and of Dyke Branch from the Kansas-Missouri border to its mouth, to determine the estimated extent of flood inundation at selected flood stages on the Blue River, Indian Creek, and Dyke Branch. The results of this study spatially interpolate information provided by U.S. Geological Survey gages, Kansas City Automated Local Evaluation in Real Time gages, and the National Weather Service flood-peak prediction service that comprise the Blue River flood-alert system and are a valuable tool for public officials and residents to minimize flood deaths and damage in Kansas City. To provide public access to the information presented in this report, a World Wide Web site (http://mo.water.usgs.gov/indep/kelly/blueriver) was created that displays the results of two-dimensional modeling between Hickman Mills Drive and 63rd Street, estimated flood-inundation maps for 13 flood stages, the latest gage heights, and National Weather Service stage forecasts for each forecast location within the study area. The results of a previous study of flood inundation on the Blue River from 63rd Street to the mouth also are available. In addition the full text of this report, all tables and maps are available for download (http://pubs.usgs.gov/sir/2008/5068). Thirteen flood-inundation maps were produced at 2-foot intervals for water-surface elevations from 763.8 to 787.8 feet referenced to the Blue River at the 63rd Street Automated Local Evaluation in Real Time stream gage operated by the city of Kansas City, Missouri. Each map is associated with gages at Kenneth Road, Blue Ridge Boulevard, Kansas City (at Bannister Road), U.S. Highway 71

  2. Time Series Models Adoptable for Forecasting Nile Floods and Ethiopian Rainfalls.

    NASA Astrophysics Data System (ADS)

    El-Fandy, M. G.; Taiel, S. M. M.; Ashour, Z. H.

    1994-01-01

    Long-term rainfall forecasting is used in making economic and agricultural decisions in many countries. It may also be a tool in minimizing the devastation resulting from recurrent droughts. To be able to forecast the total annual rainfall or the levels of seasonal floods, a class of models has first been chosen. The model parameters have then been estimated with an appropriate parameter estimation algorithm. Finally, diagnostic tests have been performed to verify the adequacy of the model. These are the general principles of system identification, which is the most crucial part of the forecasting procedure. In this paper several sets of data have been studied using different statistical procedures. The examined data include a historical 835-year record representing the levels of the seasonal Nile floods in Cairo, Egypt, during the period A.D. 622-1457. These readings were originally carried out by the Arabsto a great degree of accuracy in order to be used in estimating yearly taxes or Zacat (islamic duties). The observations also comprise recent total annual rainfall data over Addis Ababa (Ethiopia) (1907-1984), the total annual discharges of Ethiopian rivers (including the river Sobat discharges at Hillet Doleib, Blue Nile discharge at Roseris, river Dinder, river Rahar, and river Atbara), equatorial lake plateau supply as contributed at Aswan during the period 1912-1982, and the total annual discharges at Aswan during the period 1871-1982. Periodograms have been used to uncover possible peridodicities. Trends of rainfall and discharges of some rivers of east and central Africa have been also estimated.Using the first half of the available record, two autoregressive integrated moving average (ARIMA) time series models have been identified, one for the levels of the seasonal Nile floods in Cairo, the second to model the annual rainfall over Ethiopia. The time series models have been applied in 1-year-ahead forecasting to the other hall of the available record and

  3. Green-blue water in the city: quantification of impact of source control versus end-of-pipe solutions on sewer and river floods.

    PubMed

    De Vleeschauwer, K; Weustenraad, J; Nolf, C; Wolfs, V; De Meulder, B; Shannon, K; Willems, P

    2014-01-01

    Urbanization and climate change trends put strong pressures on urban water systems. Temporal variations in rainfall, runoff and water availability increase, and need to be compensated for by innovative adaptation strategies. One of these is stormwater retention and infiltration in open and/or green spaces in the city (blue-green water integration). This study evaluated the efficiency of three adaptation strategies for the city of Turnhout in Belgium, namely source control as a result of blue-green water integration, retention basins located downstream of the stormwater sewers, and end-of-pipe solutions based on river flood control reservoirs. The efficiency of these options is quantified by the reduction in sewer and river flood frequencies and volumes, and sewer overflow volumes. This is done by means of long-term simulations (100-year rainfall simulations) using an integrated conceptual sewer-river model calibrated to full hydrodynamic sewer and river models. Results show that combining open, green zones in the city with stormwater retention and infiltration for only 1% of the total city runoff area would lead to a 30 to 50% reduction in sewer flood volumes for return periods in the range 10-100 years. This is due to the additional surface storage and infiltration and consequent reduction in urban runoff. However, the impact of this source control option on downstream river floods is limited. Stormwater retention downstream of the sewer system gives a strong reduction in peak discharges to the receiving river. However due to the difference in response time between the sewer and river systems, this does not lead to a strong reduction in river flood frequency. The paper shows the importance of improving the interface between urban design and water management, and between sewer and river flood management.

  4. FAQ: General Questions about West Nile Virus

    MedlinePlus

    ... Related Links Mosquito Surveillance Software General Questions About West Nile Virus Recommend on Facebook Tweet Share Compartir ... numbers of West Nile virus cases? What is West Nile virus? West Nile virus is an arthropod- ...

  5. Integrating river basin management and the coastal zone: the (blue) Danube and the (black) sea.

    PubMed

    Maksimović, C; Makropoulos, C K

    2002-01-01

    In order to effectively manage the wide variety of physical, chemical biological and ecological processes in a sensitive coastal environment such as the Black Sea, current environmental management objectives are no longer sufficient: a new management approach has to address the intimate functional linkage between the river basin and the costal environment. Current water quality legislation requires compliance to emission levels based on the chemical analysis of water samples taken at discharge points, such as treatment plants discharging into rivers. While such measures provide a relative indication of the water quality at the point of discharge, they fail to describe accurately and sufficiently the quality of the water received from the watershed or basin. As water flows through the catchment, rainfall run-off from urban and agricultural areas carries sediments, pesticides, and other chemicals into river systems, which lead to coastal waters. The impact of the Kosovo crisis on the Danube ecosystems provides a poignant example of the effects of such diffused pollution mechanisms and reveals a number of interesting pollution mechanisms. This paper discusses both the effects of diffused pollution on the Black Sea, drawing from state-of-the-art reports on the Danube, and proposes a framework for a decision support system based on distributed hydrological and pollution transport simulation models and GIS. The use of ecological health indicators and fuzzy inference supporting decisions on regional planning within this framework is also advocated. It is also argued that even the recently produced GEF document on Black Sea protection scenarios should benefit significantly if the concept of pollution reduction from both urban, industrial and rural areas should undergo a systematic conceptual update in the view of the recent recommendations of the UNEP IETC (2000) document.

  6. Dietary exposure of great blue heron (Ardea herodias) to PCDD/DFs in the Tittabawassee River floodplain, MI, USA.

    PubMed

    Seston, Rita M; Fredricks, Timothy B; Tazelaar, Dustin L; Coefield, Sarah J; Bradley, Patrick W; Roark, Shaun A; Newsted, John L; Kay, Denise P; Zwiernik, Matthew J; Giesy, John P

    2011-03-01

    Concentrations of dioxin-like compounds, primarily polychlorinated dibenzofurans (PCDFs), in soils and sediments of the Tittabawassee River (TR) and associated floodplains downstream of Midland, Michigan (USA) were greater than upstream sites and prompted a site-specific risk assessment of great blue herons (GBH). Dietary exposure of GBH to PCDFs and polychlorinated dibenzo-p-dioxins (PCDDs) was evaluated based on site-specific concentrations of residues in prey items. Concentrations of ∑PCDD/DFs and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQ(WHO-Avian)) in prey items collected from the TR were consistently greater than those collected from associated reference areas (RAs) and further downstream in the Saginaw River (SR). The average daily dose (ADD(pot)) of ∑PCDD/DFs to GBH was 45- to 54-fold greater along the TR and 12-fold greater along the SR when compared to the RA. ∑PCDD/DFs were normalized to TEQ(WHO-Avian), and fold differences in the ADD(pot) increased, being 150- to 190-fold greater along the TR and 36-fold greater along the SR than they were in the RA. Greater fold changes in the ADD(pot) based on TEQ(WHO-Avian) between the RA and the TR and SR was due to prey items from the latter reaches having a greater relative toxic potency of ∑PCDD/DFs, primarily from greater amounts of 2,3,7,8-tetrachlorodibenzofuran but also 2,3,4,7,8-pentachlorodibenzofuran. Potential for adverse population-level effects from site-specific contaminant exposures were evaluated via comparison to selected toxicity reference values. The prediction of minimal to no risk of adverse population-level effects resultant from the assessment of site-specific dietary exposure of GBH to ∑PCDD/DFs along the TR and SR is consistent with site-specific assessments of tissue-based exposures as well as population condition.

  7. West Nile Virus

    MedlinePlus

    ... strategies visit the MedlinePlus West Nile virus site . Credit: Credit: CDC This is an enlarged view of a ... The End of an Era Acknowledgments References Photo Credits Dr. Joseph Kinyoun: Selected Bibliography NIAID 60th Anniversary ...

  8. West Nile Virus

    MedlinePlus

    ... you'll be infected with West Nile virus, mosquito bites can still be an itchy nuisance. The CDC advises people to protect themselves from mosquito bites by using mosquito repellent, especially at times ...

  9. Tracking Nile Delta vulnerability to Holocene change.

    PubMed

    Marriner, Nick; Flaux, Clément; Morhange, Christophe; Stanley, Jean-Daniel

    2013-01-01

    Understanding deltaic resilience in the face of Holocene climate change and human impacts is an important challenge for the earth sciences in characterizing the full range of present and future wetland responses to global warming. Here, we report an 8000-year mass balance record from the Nile Delta to reconstruct when and how this sedimentary basin has responded to past hydrological shifts. In a global Holocene context, the long-term decrease in Nile Delta accretion rates is consistent with insolation-driven changes in the 'monsoon pacemaker', attested throughout the mid-latitude tropics. Following the early to mid-Holocene growth of the Nile's deltaic plain, sediment losses and pronounced erosion are first recorded after ~4000 years ago, the corollaries of falling sediment supply and an intensification of anthropogenic impacts from the Pharaonic period onwards. Against the backcloth of the Saharan 'depeopling', reduced river flow underpinned by a weakening of monsoonal precipitation appears to have been particularly conducive to the expansion of human activities on the delta by exposing productive floodplain lands for occupation and irrigation agriculture. The reconstruction suggests that the Nile Delta has a particularly long history of vulnerability to extreme events (e.g. floods and storms) and sea-level rise, although the present sediment-starved system does not have a direct Holocene analogue. This study highlights the importance of the world's deltas as sensitive archives to investigate Holocene geosystem responses to climate change, risks and hazards, and societal interaction.

  10. Flood-inundation maps and wetland restoration suitability index for the Blue River and selected tributaries, Kansas City, Missouri, and vicinity, 2012

    USGS Publications Warehouse

    Heimann, David C.; Kelly, Brian P.; Studley, Seth E.

    2015-01-01

    Additional information in this report includes maps of simulated stream velocity for an 8.2-mile, two-dimensional modeled reach of the Blue River and a Wetland Restoration Suitability Index (WRSI) generated for the study area that was based on hydrologic, topographic, and land-use digital feature layers. The calculated WRSI for the selected flood-plain area ranged from 1 (least suitable for possible wetland mitigation efforts) to 10 (most suitable for possible wetland mitigation efforts). A WRSI of 5 to 10 is most closely associated with existing riparian wetlands in the study area. The WRSI allows for the identification of lands along the Blue River and selected tributaries that are most suitable for restoration or creation of wetlands. Alternatively, the index can be used to identify and avoid disturbances to areas with the highest potential to support healthy sustainable riparian wetlands.

  11. Contaminant concentrations and biomarker response in great blue heron eggs from 10 colonies on the upper Mississippi River, USA

    SciTech Connect

    Custer, T.W.; Hines, R.K.; Melancon, M.J.; Hoffman, D.J.; Wickliffe, J.K.; Bickham, J.W.; Martin, J.W.; Henshel, D.S.

    1997-02-01

    In 1993, great blue heron (Ardea herodias; GBH) eggs were collected from 10 colonies on the upper Mississippi River (UMR). They were then artificially incubated until pipping and analyzed for mercury, selenium, and organochlorines. Livers of embryos were analyzed for hepatic microsomal ethoxyresorufin-O-dealkylase (EROS) activity and four measures of oxidative stress. Brains were measured for asymmetry and blood was measured for the coefficient of variation of DNA (DNA CV). Organochlorine concentrations were generally low (geometric mean DDE = 1.3 {micro}g/g wet weight; polychlorinated biphenyl [PCB] = 3.0 {micro}g/g; 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] = 11.5 pg/g). Eggshell thickness was negatively correlated with DDE concentrations. Mercury (geometric mean = 0.8 {micro}g/g dry weight) and selenium (3.1 {micro}g/g dry weight) concentrations in GBH eggs were within background levels. EROD activity was not correlated with total PCBs, TCDD, or toxic equivalents (TEQs), based on the relative contribution of individual PCB congeners, dibenzodioxins (PCDDs), and dibenzofurans (PCDFs) to total calculated TEQs. Three of the four measures of oxidative stress were correlated with mercury concentrations. Twenty of 43 (47%) embryo brains were asymmetrical and the embryos with asymmetrical brains had higher EROD concentrations in the liver and higher DNA CV in the blood than embryos with symmetrical brains.

  12. Prehistoric Versus Historic Floodplain Sedimentation Rates in the Upper Little Tennessee River Valley, Blue Ridge Mountains, North Carolina, USA

    NASA Astrophysics Data System (ADS)

    Leigh, D. S.

    2008-12-01

    Late prehistoric and historic floodplain sedimentation rates were examined along the Upper Little Tennessee River within a 363 km2 catchment of the Southern Blue Ridge Mountains in western North Carolina. Sedimentation rates were derived from stratigraphy, sedimentology, radiocarbon and cesium-137 dates at three mainstem floodplain sample sites using cores and outcrops. Particle size was measured in continuous down-column overbank sediment samples (1-3 cm increments) to document individual floods as time markers. Results indicate that late prehistoric sedimentation rates were less than 1 mm/yr, whereas historical sedimentation rates are about an order of magnitude higher (5 to 17 mm/yr). The historical floodplain has accreted up to two meters higher than prehistoric levels, while the channel bed remains approximately at prehistoric levels. The most rapid historical sedimentation rates of 13-17 mm/yr occurred between 1963 and 2004, corresponding to a time period of second home construction, road construction, and other erosive land uses related to population and infrastructure growth; whereas pre-1963 historical sedimentation rates correspond to former timber harvest and agricultural activities. The most recent phase from1963 to present also corresponds to a time of relatively rapid lateral migration, incipient floodplain formation, and natural levee progradation on historically terraced cutbanks. Ongoing research relates channel morphogenesis, bank erosion, and remobilization of historical sediment to the overall sediment budget.

  13. Metal Concentrations, Foraging Distances, and Fledging Success of Great Blue Herons Nesting Along the Hanford Reach of the Columbia River

    SciTech Connect

    Tiller, Brett L.; Marco, Jeffrey D.; Rickard, William H.

    2005-05-01

    Excrement sample and livers of juvenile great blue herons were collected at nests at three widely separated colonies along the Hanford Reach of the Columbia River to test the validity of using excrement samples as indicators of metal concentrations in tissues of juvenile herons fed food collected by parent birds within a few kilometers of nests. There was no positive relation noted between metal concentrations in excrement and liver samples taken from the same nests. Statistically significant differences in metal concentrations were noted in excrement samples collected among the different heron colonies. Arsenic, Cd, Cr, and Pb concentrations (dry wt.) were higher in excrement than in liver samples but the opposite was noted for Cu, Hg, and Zn. Mercury concentrations in heron liver samples were biomagnified to a greater extent than Cd and Cr. Fledging success and eggshell thickness measurements were used as indicators of population health. These values were equivalent to or better than those noted for heron colonies elsewhere in the United States.

  14. Contaminant concentrations and biomarker response in great blue heron eggs from 10 colonies on the upper Mississippi River, USA

    USGS Publications Warehouse

    Custer, T.W.; Hines, R.K.; Melancon, M.J.; Hoffman, D.J.; Wickliffe, J.K.; Bickham, J.W.; Martin, J.W.; Henshel, D.S.

    1997-01-01

    In 1993, great blue heron (Ardea herodias; GBH) eggs were collected from 10 colonies on the upper Mississippi River (UMR). They were then artificially incubated until pipping and analyzed for mercury, selenium, and organochlorines. Livers of embryos were analyzed for hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) and four measures of oxidative stress. Brains were measured for asymmetry and blood was measured for the coefficient of variation of DNA (DNA VC). Organochlorine concentrations were generally low (geometric mean DDE = 1.3 ug/g wet weight; polychlorinated biphenyl [PCB] = 3.0 ug/g; 2,3,7,8-tetrachloro- -dioxin [TCDD] = 11.5 pg/g). Eggshell thickness was negatively correlated with DDE concentrations. Mercury (geometric mean = 0.8 ug/g dry weight) and selenium (3.1 ug/g dry weight) concentrations in GBH eggs were within background levels. EROD activity was not correlated with total PCBs, TCDD or toxic equivalents (TEQs) based on the relative contribution of individual PCB congeners, dibenzodioxins (PCDDs), and dibenzofurans (PCDFs) to calculated TEQs. Three of the four measures of oxidative stress were correlated with mercury concentrations. Twenty of 43 (47%) embryo brains were asymmetrical and the embryos with asymmetrical brains had higher EROD concentrations in the liver and higher DNA CV in the blood than embryos with symmetrical brains.

  15. Contaminant concentrations and biomarker response in great blue heron eggs from 10 colonies on the upper Mississippi River, USA

    USGS Publications Warehouse

    Custer, T.W.; Hines, R.K.; Melancon, M.J.; Hoffman, D.J.; Wickliffe, J.K.; Bickham, J.W.; Martin, J.W.; Henshel, D.S.

    1997-01-01

    In 1993, great blue heron (Ardea herodias; GBH) eggs were collected from 10 colonies on the upper Mississippi River (UMR). They were then artificially incubated until pipping and analyzed for mercury, selenium, and organochlorines. Livers of embryos were analyzed for hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity and four measures of oxidative stress. Brains were measured for asymmetry and blood was measured for the coefficient of variation of DNA (DNA CV). Organochlorine concentrations were generally low (geometric mean DDE = 1.3 I?g/g wet weight; polychlorinated biphenyl [PCB] = 3.0 I?g/g; 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] = 11.5 pg/g). Eggshell thickness was negatively correlated with DDE concentrations. Mercury (geometric mean = 0.8 I?g/g dry weight) and selenium (3.1 I?g/g dry weight) concentrations in GBH eggs were within background levels. EROD activity was not correlated with total PCBs, TCDD, or toxic equivalents (TEQs), based on the relative contribution of individual PCB congeners, dibenzodioxins (PCDDs), and dibenzofurans (PCDFs) to total calculated TEQs. Three of the four measures of oxidative stress were correlated with mercury concentrations. Twenty of 43 (47%) embryo brains were asymmetrical and the embryos with asymmetrical brains had higher EROD concentrations in the liver and higher DNA CV in the blood than embryos with symmetrical brains.

  16. Effects of pumping municipal wells at Manhattan, Kansas, on streamflow in the Big Blue and Kansas Rivers, Northeast Kansas, 1992-94

    USGS Publications Warehouse

    Jian, Xiaodong; Myers, N.C.; Hargadine, G.D.

    1997-01-01

    A ground-water flow model was developed to simulate the effects of municipal well pumping on streamflow in the Big Blue and Kansas Rivers near Manhattan, Kansas, from 1992 through 1994.Model simulations of the effects of municipal well pumping on streamflow in the Big Blue and Kansas Rivers indicate that well pumping decreases streamflow. Simulations of May 1993 conditions indicate that well pumping decreased simulated streamflow in the Big Blue and Kansas Rivers by 5.28 ft3/s (cubic feet per second) for the month, of which 3.22 ft3/s were contributed from the streams (induced infiltration) and 2.06 ft3/s werecontributed from ground water that would have seeped to the streams if the wells had not been pumping (intercepted base flow). Of the total 414acre-feet pumped by municipal wells during May 1993, about 48 percent was from induced infiltration, and about 31 percent was from intercepted base flow. Simulations of October 16 through November 14, 1994, conditions indicate that well pumping decreased simulated streamflow in the Big Blue and Kansas Rivers by 6.67 ft3/s for the period, of which 6.51 ft3/s was from induced infiltration and 0.61 ft3/s was from intercepted base flow. Of the 506 acre-feet pumped by municipal wells during October 16 through November 14, 1994, about 76 percent was induced from infiltration, and about 2 percent was from intercepted base flow. Steady-state simulations of hypothetical conditions were conducted to develop relations among average and minimum ground- water altitudes in the Manhattan municipal well field and precipitation, pumping, and streamflow rates.

  17. 10. GENERAL VIEW OF NILES TREAD LATHE, Niles Tool Company, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. GENERAL VIEW OF NILES TREAD LATHE, Niles Tool Company, Hamilton, Ohio. - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  18. 'Blue energy' from ion adsorption and electrode charging in sea and river water

    NASA Astrophysics Data System (ADS)

    Boon, Niels; van Roij, René

    2011-03-01

    A huge amount of entropy is produced at places where fresh water and seawater mix, for example at river mouths. This mixing process is a potentially enormous source of sustainable energy, provided it is harnessed properly, for instance by a cyclic charging and discharging process of porous electrodes immersed in salt and fresh water, respectively [D. Brogioli, Phys. Rev. Lett. 103, 058501 (2009)]. Here we employ a modified Poisson-Boltzmann free-energy density functional to calculate the ionic adsorption and desorption onto and from the charged electrodes, from which the electric work of a cycle is deduced. We propose optimal (most efficient) cycles for two given salt baths involving two canonical and two grand-canonical (dis)charging paths, in analogy to the well-known Carnot cycle for heat-to-work conversion from two heat baths involving two isothermal and two adiabatic paths. We also suggest a slightly modified cycle which can be applied in cases that the stream of fresh water is limited.

  19. Evapotranspiration (ET) at Blue Cypress marsh site, daily data, Indian River County, Florida, June 1, 1995 – October 20, 2014

    USGS Publications Warehouse

    Sumner, David M.

    2017-01-01

    This U.S. Geological Survey (USGS) data release consists of daily evapotranspiration (ET) measurements/estimates for the time period June 1, 1995 to October 2014. These data are derived from (1) measurements of actual ET conducted at the USGS Blue Cypress marsh station (USGS station number 274143080424100) and (2) estimates of actual ET inferred from statistical regressions between the measurements of actual ET and potential ET. The station is located at a nearly flat wetlands site (27 degrees 41 minutes 43 seconds North / 080 degrees 42 minutes 41 seconds West) within the Blue Cypress Marsh Conservation Area, Indian River County, Florida. The dominant plant cover at the study site is sawgrass (Cladium jamaicense), with secondary amounts of other wetland plant species. Sawgrass height generally varies from 1.8 to 2.4 meters. The canopy can be temporarily removed through fire, followed by rapid re-growth. The soils at the site are peats. The water-table generally is above land surface but can be greater than a meter below land surface during droughts. Actual ET measurements derived using the eddy-covariance method are available for January 1, 2000 to September 1, 2005; and December 11, 2009 to October 20, 2014. The contribution of the present Data Release is dissemination of a dataset of actual ET estimates for a period prior to the first period of actual ET measurements (June 1, 1995 to December 31, 1999) and for the time interval between the two periods of actual ET measurement (September 2, 2005 to December 10, 2009). Estimates of actual ET during periods of missing actual ET measurements were obtained using regression-determined, monthly vegetation coefficient multipliers applied to potential ET data. The source of potential ET data was an existing Statewide database developed through an assimilation of satellite- and field-based meterological data. A seamless time series of measured and estimated actual ET for the period June 1, 1999 to December 10, 2014 is

  20. Effects of wastewater and combined sewer overflows on water quality in the Blue River basin, Kansas City, Missouri and Kansas, July 1998-October 2000

    USGS Publications Warehouse

    Wilkison, Donald H.; Armstrong, Daniel J.; Blevins, Dale W.

    2002-01-01

    Samples were collected from 16 base-flow events and a minimum of 10 stormflow events between July 1998 and October 2000 to characterize the effects of wastewater and combined sewer overflows on water quality in the Blue River Basin, Kansas City, Missouri and Kansas. Waterquality effects were determined by analysis of nutrients, chloride, chemical and biochemical oxygen demand, and suspended sediment samples from three streams (Blue River, Brush Creek, and Indian Creek) in the basin as well as the determination of a suite of compounds known to be indicative of wastewater including antioxidants, caffeine, detergent metabolites, antimicrobials, and selected over-the-counter and prescription pharmaceuticals. Constituent loads were determined for both hydrologic regimes and a measure of the relative water-quality impact of selected stream reaches on the Blue River and Brush Creek was developed. Genetic fingerprint patterns of Escherichia coli bacteria from selected stream samples were compared to a data base of knownsource patterns to determine possible sources of bacteria. Water quality in the basin was affected by wastewater during both base flows and stormflows; however, there were two distinct sources that contributed to these effects. In the Blue River and Indian Creek, the nearly continuous discharge of treated wastewater effluent was the primary source of nutrients, wastewater indicator compounds, and pharmaceutical compounds detected in stream samples. Wastewater inputs into Brush Creek were largely the result of intermittent stormflow events that triggered the overflow of combined storm and sanitary sewers, and the subsequent discharge of untreated wastewater into the creek. A portion of the sediment, organic matter, and associated constituents from these events were trapped by a series of impoundments constructed along Brush Creek where they likely continued to affect water quality during base flow. Concentrations and loads of most wastewater constituents in

  1. Multi-century tree-ring precipitation record reveals increasing frequency of extreme dry events in the upper Blue Nile River catchment.

    PubMed

    Mokria, Mulugeta; Gebrekirstos, Aster; Abiyu, Abrham; Van Noordwijk, Meine; Bräuning, Achim

    2017-07-16

    Climate-related environmental and humanitarian crisis are important challenges in the Great Horn of Africa (GHA). In the absence of long-term past climate records in the region, tree-rings are valuable climate proxies, reflecting past climate variations and complementing climate records prior to the instrumental era. We established annually resolved multi-century tree-ring chronology from Juniperus procera trees in northern Ethiopia, the longest series yet for the GHA. The chronology correlates significantly with wet-season (r = .64, p < .01) and annual (r = .68, p < .01) regional rainfall. Reconstructed rainfall since A.D. 1811 revealed significant interannual variations between 2.2 and 3.8 year periodicity, with significant decadal and multidecadal variations during 1855-1900 and 1960-1990. The duration of negative and positive rainfall anomalies varied between 1-7 years and 1-8 years. Approximately 78.4% (95%) of reconstructed dry (extreme dry) and 85.4% (95%) of wet (extreme wet) events lasted for 1 year only and corresponded to historical records of famine and flooding, suggesting that future climate change studies should be both trend and extreme event focused. The average return periods for dry (extreme dry) and wet (extreme wet) events were 4.1 (8.8) years and 4.1 (9.5) years. Extreme-dry conditions during the 19th century were concurrent with drought episodes in equatorial eastern Africa that occurred at the end of the Little Ice Age. El Niño and La Niña events matched with 38.5% and 50% of extreme-dry and extreme-wet events. Equivalent matches for positive and negative Indian Ocean Dipole events were weaker, reaching 23.1 and 25%, respectively. Spatial correlations revealed that reconstructed rainfall represents wet-season rainfall variations over northern Ethiopia and large parts of the Sahel belt. The data presented are useful for backcasting climate and hydrological models and for developing regional strategic plans to manage scarce and contested water resources. Historical perspectives on long-term regional rainfall variability improve the interpretation of recent climate trends. © 2017 John Wiley & Sons Ltd.

  2. The impact of river water intrusion on trace metal cycling in karst aquifers: an example from the Floridan aquifer system at Madison Blue Spring, Florida

    NASA Astrophysics Data System (ADS)

    Brown, A. L.; Martin, J. B.; Screaton, E.; Spellman, P.; Gulley, J.

    2011-12-01

    Springs located adjacent to rivers can serve as recharge points for aquifers when allogenic runoff increases river stage above the hydraulic head of the spring, forcing river water into the spring vent. Depending on relative compositions of the recharged water and groundwater, the recharged river water could be a source of dissolved trace metals to the aquifer, could mobilize solid phases such as metal oxide coatings, or both. Whether metals are mobilized or precipitated should depend on changes in redox and pH conditions as dissolved oxygen and organic carbon react following intrusion of the river water. To assess how river intrusion events affect metal cycling in springs, we monitored a small recharge event in April 2011 into Madison Blue Spring, which discharges to the Withlacoochee River in north-central Florida. Madison Blue Spring is the entrance to a phreatic cave system that includes over 7.8 km of surveyed conduits. During the event, river stage increased over base flow conditions for approximately 25 days by a maximum of 8%. Intrusion of the river water was monitored with conductivity, temperature and depth sensors that were installed within the cave system and adjacent wells. Decreased specific conductivity within the cave system occurred for approximately 20 days, reflecting the length of time that river water was present in the cave system. During this time, grab samples were collected seven times over a period of 34 days for measurements of major ion and trace metal concentrations at the spring vent and at Martz sink, a karst window connected to the conduit system approximately 150 meters from the spring vent. Relative fractions of surface water and groundwater were estimated based on Cl concentrations of the samples, assuming conservative two end-member mixing during the event. This mixing model indicates that maximum river water contribution to the groundwater system was approximately 20%. River water had concentrations of iron, manganese, and other

  3. Export and losses of blue carbon-derived particulate and dissolved organic carbon (POC and DOC) in blackwater river-dominated and particle-dominated estuaries

    NASA Astrophysics Data System (ADS)

    Arellano, A. R.; Bianchi, T. S.; Osburn, C. L.; D'Sa, E. J.; Oviedo Vargas, D.; Ward, N. D.; Joshi, I.; Ko, D. S.

    2016-12-01

    Globally, coastal blue carbon environments (wetlands, seagrass beds and mangroves) sequester an estimated 67-215 Tg C yr-1. While most blue carbon research has focused on carbon burial/stocks and habitat fragmentation of these communities, few studies have examined the export and loss of blue carbon sources of particulate organic matter (POM) and dissolved organic matter (DOM) to adjacent coastal waters. These shifts in losses of DOM and POM are also partly due to large-scale changes in land-use and climate change. Due to the complexity of vascular plant inputs to estuarine systems (e.g. terrestrial vs. blue carbon), being able to separate blue carbon sources of POM and DOM are critical. Here, we investigate the temporal variability of the abundance, sources and breakdown of particulate and dissolved organic carbon (POC and DOC) in particle-dominated (Barataria Bay) and blackwater river-dominated (Apalachicola Bay) estuaries in the northern Gulf of Mexico, using bulk carbon, dissolved lignin phenols, δ13C and dissolved CO2. The range of DOC:POC ratios for Barataria and Apalachicola bays were 0.5-3.1 and 2.3-57.0, respectively. δ13C-POC values were more depleted in Apalachicola (x̅=-27.3‰) compared to those in Barataria (x̅=-24.8‰), and C:N ratios were higher in Apalachicola (x̅=10.8) than in Barataria (x̅=9.3). Although there was no significant temporal variability with δ13C-POC in both systems, Barataria Bay had the highest POC (0.08-0.23 mM) and C:N (7.0-13.4) values during spring, when enhanced southerly winds likely resulted in higher resuspension and marsh erosion rates. Additionally, in Apalachicola, the lowest C:N values (6.2-16.1) were observed during the dry season when fluvial DOM inputs were minimal. The highest dissolved lignin phenol and DOC (0.10-2.98 mM) concentrations in Apalachicola occurred during the wet season, reflecting the importance of riverine inputs to this system. In particular, the Carabelle River plume region had C:V and S

  4. Redox-induced mobilization of copper, selenium, and zinc in deltaic soils originating from Mississippi (U.S.A.) and Nile (Egypt) River Deltas: A better understanding of biogeochemical processes for safe environmental management.

    PubMed

    Shaheen, Sabry M; Frohne, Tina; White, John R; DeLaune, Ron D; Rinklebe, Jörg

    2017-01-15

    Studies about the mobilization of potentially toxic elements (PTEs) in deltaic soils can be challenging, provide critical information on assessing the potential risk and fate of these elements and for sustainable management of these soils. The impact of redox potential (EH), pH, iron (Fe), manganese (Mn), sulfate (SO4(2-)), chloride (Cl(-)), aliphatic dissolved organic carbon (DOC), and aromatic dissolved organic carbon (DAC) on the mobilization of copper (Cu), selenium (Se), and zinc (Zn) was studied in two soils collected from the Nile and Mississippi Rivers deltaic plains focused on increasing our understanding of the fate of these toxic elements. Soils were exposed to a range of redox conditions stepwise from reducing to oxidizing soil conditions using an automated biogeochemical microcosm apparatus. Concentrations of DOC and Fe were high under reducing conditions as compared to oxidizing conditions in both soils. The proportion of DAC in relation to DOC in solution (aromaticity) was high in the Nile Delta soil (NDS) and low in the Mississippi Delta soil (MDS) under oxidizing conditions. Mobilization of Cu was low under reducing conditions in both soils which was likely caused by sulfide precipitation and as a result of reduction of Cu(2+) to Cu(1+). Mobilization of Se was high under low EH in both soils. Release of Se was positively correlated with DOC, Fe, Mn, and SO4(2-) in the NDS, and with Fe in the MDS. Mobilization of Zn showed negative correlations with EH and pH in the NDS while these correlations were non-significant in the MDS. The release dynamics of dissolved Zn could be governed mainly by the chemistry of Fe and Mn in the NDS and by the chemistry of Mn in the MDS. Our findings suggest that a release of Se and Zn occurs under anaerobic conditions, while aerobic conditions favor the release of Cu in both soils. In conclusion, the release of Cu, Se, and Zn under different reducing and oxidizing conditions in deltaic wetland soils should be taken into

  5. City Lights Illuminate the Nile

    NASA Image and Video Library

    2017-09-27

    NASA image acquired October 13, 2012 The Nile River Valley and Delta comprise less than 5 percent of Egypt’s land area, but provide a home to roughly 97 percent of the country’s population. Nothing makes the location of human population clearer than the lights illuminating the valley and delta at night. On October 13, 2012, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime view of the Nile River Valley and Delta. This image is from the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as gas flares, auroras, wildfires, city lights, and reflected moonlight. The city lights resemble a giant calla lily, just one with a kink in its stem near the city of Luxor. Some of the brightest lights occur around Cairo, but lights are abundant along the length of the river. Bright city lights also occur along the Suez Canal and around Tel Aviv. Away from the lights, however, land and water appear uniformly black. This image was acquired near the time of the new Moon, and little moonlight was available to brighten land and water surfaces. NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Michon Scott. Instrument: Suomi NPP - VIIRS Credit: NASA Earth Observatory Click here to view all of the Earth at Night 2012 images Click here to read more about this image NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency

  6. Trace element and isotopic composition of apatite in carbonatites from the Blue River area (British Columbia, Canada) and mineralogy of associated silicate rocks

    NASA Astrophysics Data System (ADS)

    Mitchell, Roger; Chudy, Thomas; McFarlane, Christopher R. M.; Wu, Fu-Yuan

    2017-08-01

    Apatites from the Verity, Fir, Gum, Howard Creek and Felix carbonatites of the Blue River (British Columbia, Canada) area have been investigated with respect to their paragenesis, cathodoluminescence, trace element and Sr-Nd isotopic composition. Although all of the Blue River carbonatites were emplaced as sills prior to amphibolite grade metamorphism and have undergone deformation, in many instances magmatic textures and mineralogy are retained. Attempts to constrain the U-Pb age of the carbonatites by SIMS, TIMS and LA-ICP-MS studies of zircon and titanite were inconclusive as all samples investigated have experienced significant Pb loss during metamorphism. The carbonatites are associated with undersaturated calcite-titanite amphibole nepheline syenite only at Howard Creek although most contain clasts of disaggregated phoscorite-like rocks. Apatite from each intrusion is characterized by distinct, but wide ranges, in trace element composition. The Sr and Nd isotopic compositions define an array on a 87Sr/86Sr vs²Nd diagram at 350 Ma indicating derivation from depleted sub-lithospheric mantle. This array could reflect mixing of Sr and Nd derived from HIMU and EM1 mantle sources, and implies that depleted mantle underlies the Canadian Cordillera. Although individual occurrences of carbonatites in the Blue River region are mineralogically and geochemically similar they are not identical and thus cannot be considered as rocks formed from a single batch of parental magma at the same stage of magmatic evolution. However, a common origin is highly probable. The variations in the trace element content and isotopic composition of apatite from each occurrence suggest that each carbonatite represents a combination of derivation of the parental magma(s) from mineralogically and isotopically heterogeneous depleted mantle sources coupled with different stages of limited differentiation and mixing of these magmas. We do not consider these carbonatites as primary direct

  7. Watershed Models for Decision Support in the Yakima River Basin, Washington

    DTIC Science & Technology

    2002-01-01

    River below Tieton Dam in the Yakima River Basin, Washington...daily streamflow for water years 1956-65 for Tieton River below Tieton Dam , the American River near Nile, and the South Fork Ahtanum Creek at Conrad...years 1976 and 1977 for the American River near Nile and the Tieton River at Tieton Dam , Naches River Basin, in the Yakima River Basin, Washington

  8. West Nile Virus

    MedlinePlus

    ... spread by mosquitoes. Mosquitoes become infected by biting birds that carry the virus. People can get West Nile virus when an infected mosquito bites them. This happens most often in the warm-weather months of spring, summer and early fall. You ...

  9. Effects of Harvest and Roads on In-stream Woody Material in Blue River Basin, Cascade Range, Oregon

    NASA Astrophysics Data System (ADS)

    Czarnomski, N. M.; Dreher, D. M.; Jones, J. A.; Swanson, F. J.

    2003-12-01

    Despite many studies of large wood in streams, few landscape-scale studies have been conducted, and yet the history of forest harvest and road building might be expected to have left a signal on wood patterns in streams. This study examined this question at large (>50 km2) spatial and long (>25 year) temporal scales, based on longitudinal surveys of 25.2 km of stream length in five sub-basins of the Blue River Basin, Cascade Range, Oregon. Six sites, ranging from 1.6 km to 14.1 km in length, were surveyed along 2nd to 5th-order channels on public forest land. Wood volumes, numbers of pieces of large wood, numbers of accumulations and timing of emplacement were determined in the surveys. Survey data were matched with spatial data on harvest and road building practices using GIS. Study streams have undergone distributed patch clearcutting and road construction concentrated during the 1950s and 1960s. The proportions of surveyed stream lengths with harvest and road activities within 40 m was 66% (Cook Creek), 55% (Mack Creek), 53% (Lower Lookout), 37% (McRae Creek and Upper Lookout), and 7% (Quentin Creek). For all study locations combined, 50-m channel segments when there is no harvest or road influence had an average of 356 m3/ha, whereas harvested and roaded areas had from 80 to 157 m3/ha (Bonferroni adjusted p<0.03). Approximately 80% of the wood volume occurred in accumulations. The 5th-order channel (Lower Lookout) had significantly lower wood volumes (109 m3/ha) than all other locations (200-378 m3/ha, Bonferroni adjusted p < 0.05) and significantly lower numbers of large pieces (23 large pieces/ha) compared to all other locations (39 vs. 64 large pieces/ha) (Bonferroni adjusted p<0.008). Thus, the legacy of harvest and road activities conducted in the 1950s and 1960s was still apparent in in-stream wood patterns nearly 40 years later.

  10. Developmental alterations and endocrine-disruptive responses in farmed Nile crocodiles (Crocodylus niloticus) exposed to contaminants from the Crocodile River, South Africa.

    PubMed

    Arukwe, Augustine; Myburgh, Jan; Langberg, Håkon A; Adeogun, Aina O; Braa, Idunn Godal; Moeder, Monika; Schlenk, Daniel; Crago, Jordan Paul; Regoli, Francesco; Botha, Christo

    2016-04-01

    In the present study, the developmental (including fertility) and endocrine-disruptive effects in relation to chemical burden in male and female Nile crocodiles (Crocodylus niloticus), from a commercial crocodile farm in the Brits district, South Africa, exposed to various anthropogenic aquatic contaminants from the natural environment was investigated. Hepatic transcript levels for vitellogenin (Vtg), zona pellucida (ZP) and ERα (also in gonads) were analyzed using real-time PCR. Plasma estradiol-17β (E2), testosterone (T) and 11-ketotestosterone (11-KT) were analyzed using enzyme immunoassay. Gonadal aromatase and hepatic testosterone metabolism (6β-hydroxylase (6β-OHase)) were analyzed using biochemical methods. Overall, there is high and abnormal number (%) of infertile and banded eggs during the studied reproductive seasons, showing up to 57 and 34% of infertile eggs in the 2009/2010 and 2013/2014 seasons, respectively. In addition, the percentage of banded eggs ranged between 10 and 19% during the period of 2009-2014 seasons. While hepatic ERα, Vtg, ZP mRNA and testosterone 6β-OHase, were equally expressed in female and male crocodiles, gonadal ERα mRNA and aromatase activity were significantly higher in females compared to male crocodiles. On the other hand, plasma T and 11-KT levels were significantly higher in males, compared to female crocodiles. Principal component analysis (PCA) produced significant grouping that revealed correlative relationships between reproductive/endocrine-disruptive variables and liver contaminant burden, that further relates to measured contaminants in the natural environment. The overall results suggest that these captive pre-slaughter farm crocodiles exhibited responses to anthropogenic aquatic contaminants with potentially relevant consequences on key reproductive and endocrine pathways and these responses may be established as relevant species endocrine disruptor biomarkers of exposure and effects in this threatened

  11. FAQ: West Nile Virus and Dead Birds

    MedlinePlus

    ... Education Public Service Videos West Nile Virus & Dead Birds Recommend on Facebook Tweet Share Compartir On This ... dead bird sightings to local authorities. How do birds get infected with West Nile virus? West Nile ...

  12. Water-quality and biologic data for the Blue River basin, Kansas City metropolitan area, Missouri and Kansas, October 2000 to October 2004

    USGS Publications Warehouse

    Wilkison, Donald H.; Armstrong, Daniel J.; Brown, Rebecca E.; Poulton, Barry C.; Cahill, Jeffrey D.; Zaugg, Steven D.

    2005-01-01

    This report presents water-quality and biologic data collected in the Blue River Basin, metropolitan Kansas City, Missouri and Kansas, from October 2000 to October 2004. Data were collected in cooperation with the city of Kansas City, Missouri, Water Services Department as part of an ongoing study designed to characterize long-term water-quality trends in the basin and to provide data to support a strategy for combined sewer overflow control. These data include values of physical properties, fecal indicator bacteria densities, suspended sediment, and concentrations of major ions, nutrients, trace elements, organic wastewater compounds, and pharmaceutical compounds in base-flow and stormflow stream samples and bottom sediments. Six surface-water sites in the basin were sampled 13 times during base-flow conditions and during a minimum of 7 storms. Benthic macroinvertebrate communities are described at 10 sites in the basin and 1 site outside the basin. Water-column and bottom-sediment data from impounded reaches of Brush Creek are provided. Continuous specific conductance, pH, water-quality temperature, turbidity, and dissolved oxygen data are provided for two streams-the Blue River and Brush Creek. Sampling, analytical, and quality assurance methods used in data collection during the study also are described in the report.

  13. A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for West Fork Blue River, Washington County, Indiana

    USGS Publications Warehouse

    Peters, James G.; Wilber, W.G.; Crawford, Charles G.; Girardi, F.P.

    1979-01-01

    A digital computer model calibrated to observe stream conditions was used to evaluate water quality in West Fork Blue River, Washington County, IN. Instream dissolved-oxygen concentration averaged 96.5% of saturation at selected sites on West Fork Blue River during two 24-hour summer surveys. This high dissolved-oxygen concentration reflects small carbonaceous and nitrogenous waste loads; adequate dilution of waste by the stream; and natural reaeration. Nonpoint source waste loads accounted for an average of 53.2% of the total carbonaceous biochemical-oxygen demand and 90.2% of the nitrogenous biochemical-oxygen demand. Waste-load assimilation was studiedfor critical summer and winter low flows. Natural streamflow for these conditions was zero, so no benefit from dilution was provided. The projected stream reaeration capacity was not sufficient to maintain the minimum daily dissolved-oxygen concentration (5 milligrams per liter) in the stream with current waste-discharge restrictions. During winter low flow, ammonia toxicity, rather than dissolved-oxygen concentration, was the limiting water-quality criterion downstream from the Salem wastewater-treatment facility. (USGS)

  14. Orbital forcing of glacial/interglacial variations in chemical weathering within the White Nile basin: stable-isotope and biomarker evidence from Lakes Victoria and Edward

    NASA Astrophysics Data System (ADS)

    Cockerton, Helen E.; Alayne Street-Perrott, F.; Barker, Philip A.; Leng, Melanie J.; Sloane, Hilary J.; Horstwood, Matthew S. A.; Snelling, Andrea

    2014-05-01

    The continental Si cycle on Quaternary time scales has been largely neglected. Emphasis has been placed on long-term geochemical processes of silicate-rock weathering and the resulting drawdown of atmospheric CO2, rather than on shorter-term biogenic processes occurring along the land-ocean continuum. Si-accumulating plants (notably tropical rainforest hardwoods, savanna and wetland grasses, and Papyrus) and aquatic organisms (such as diatoms and sponges in lakes, rivers and swamps) have the potential to take up, store and recycle significant amounts of Si, thereby modifying the riverine flux of Si to the oceans, the productivity of siliceous marine organisms and the rate of atmospheric CO2 drawdown on an orbital time scale. The main aim of this study was to investigate spatial and temporal patterns of Si cycling along the Nile system during the last 20ka BP. Utilising sediment cores from Lakes Victoria and Edward, coupled measurements of stable Si and O isotopes on cleaned diatom separates were employed to reconstruct millennial-scale variations in biotic Si cycling and palaeohydrology, respectively. Abundance ratios of lipid biomarkers (n-alkanes) were used to track major changes in terrestrial and aquatic ecosystems. The results have been interpreted in the light of multi-isotope analyses (2H,18O,30Si) of modern water samples collected along the courses of the modern White and Blue Niles during both wet- and dry-season conditions. During drier intervals (the Last Glacial Maximum and the late Holocene: high 18Odiatom), Si cycling was greatly reduced. Diminished vegetation cover, reduced biotic rock weathering, a declining soil stock of amorphous silica (ASi) and decreased runoff resulted in reduced dissolved silica (DSi) supply to the lakes in relation to aquatic demand (high 30Sidiatom). In contrast, enhanced monsoon rainfall (low 18Odiatom) during the early to mid-Holocene promoted a substantial increase in terrestrial biomass within the White Nile headwaters

  15. Response of the Nile and its catchment to millennial-scale climatic change since the LGM from Sr isotopes and major elements of East Mediterranean sediments

    NASA Astrophysics Data System (ADS)

    Box, M. R.; Krom, M. D.; Cliff, R. A.; Bar-Matthews, M.; Almogi-Labin, A.; Ayalon, A.; Paterne, M.

    2011-02-01

    Changes in 87Sr/ 86Sr and major element geochemistry, from two sediment cores (9509 and 9501) in the Eastern Mediterranean (EM), were used to resolve changes in sediment provenance and, hence, determine climate changes in the Nile catchment and Eastern Sahara desert over the past 25 ka. The sediment was described by a three end-member system comprising Blue Nile (BN; 87Sr/ 86Sr = 0.7506; Sr = 210 ppm), White Nile (WN; 87Sr/ 86Sr = 0.7094; Sr = 72.5 ppm) and Saharan dust (SD; 87Sr/ 86Sr = 0.7183; Sr = 99 ppm). The sedimentary record of these cores represents the suspended load carried down the Nile river and discharged into the S.E. Levantine basin and thus records palaeoclimatically controlled changes in erosion and transport in the catchment. During arid periods (0-5 ka BP) and prior to 11 ka BP, fluxes of BN sediment at 9509 (˜6 g/cm 2/yr & 10-12 g/cm 2/yr, respectively) were greater than during the peak of the African Humid Period (AHP) from 5 to 11 ka BP (<2 g/cm 2/yr); this latter period witnessed the deposition of the youngest organic-rich sediment, termed sapropel (S-1), in the EM basin. By contrast the flux of WN increased during the AHP from ˜5 g/cm 2/yr at ˜13 ka BP to >15 g/cm 2/yr. In the Ethiopian Highlands (BN catchment) increases in the amount and duration of the monsoon during the AHP caused more vegetation to grow resulting in less soil erosion. In the WN catchment increased rainfall caused more catchment erosion and higher sediment flux through the Sudd marshes. The sedimentation rate in core 9509 increased during the AHP because of the greater importance of the WN sediment flux relative to the BN sediment flux. Saharan dust flux also decreased during the AHP reaching a minimum at ˜6 ka BP (core 9509) due to 'greening' of the Sahara desert. At the onset of S-1, the changes in Nile flow as determined by 87Sr/ 86Sr and climatic changes in the EM basin determined by δ 18O of planktonic foraminifera were simultaneous, confirming that such

  16. Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label.

    PubMed

    Yotapan, Nattawut; Charoenpakdee, Chayan; Wathanathavorn, Pawinee; Ditmangklo, Boonsong; Wagenknecht, Hans-Achim; Vilaivan, Tirayut

    2014-01-01

    DNA or its analogues with an environment-sensitive fluorescent label are potentially useful as a probe for studying the structure and dynamics of nucleic acids. In this work, pyrrolidinyl peptide nucleic acid (acpcPNA) was labeled at its backbone with Nile red, a solvatochromic benzophenoxazine dye, by means of click chemistry. The optical properties of the Nile red-labeled acpcPNA were investigated by UV-vis and fluorescence spectroscopy in the absence and in the presence of DNA. In contrast to the usual quenching observed in Nile red-labeled DNA, the hybridization with DNA resulted in blue shifting and an enhanced fluorescence regardless of the neighboring bases. More pronounced blue shifts and fluorescence enhancements were observed when the DNA target carried a base insertion in close proximity to the Nile red label. The results indicate that the Nile red label is located in a more hydrophobic environment in acpcPNA-DNA duplexes than in the single-stranded acpcPNA. The different fluorescence properties of the acpcPNA hybrids of complementary DNA and DNA carrying a base insertion are suggestive of different interactions between the Nile red label and the duplexes.

  17. Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

    PubMed Central

    Yotapan, Nattawut; Charoenpakdee, Chayan; Wathanathavorn, Pawinee; Ditmangklo, Boonsong

    2014-01-01

    Summary DNA or its analogues with an environment-sensitive fluorescent label are potentially useful as a probe for studying the structure and dynamics of nucleic acids. In this work, pyrrolidinyl peptide nucleic acid (acpcPNA) was labeled at its backbone with Nile red, a solvatochromic benzophenoxazine dye, by means of click chemistry. The optical properties of the Nile red-labeled acpcPNA were investigated by UV–vis and fluorescence spectroscopy in the absence and in the presence of DNA. In contrast to the usual quenching observed in Nile red-labeled DNA, the hybridization with DNA resulted in blue shifting and an enhanced fluorescence regardless of the neighboring bases. More pronounced blue shifts and fluorescence enhancements were observed when the DNA target carried a base insertion in close proximity to the Nile red label. The results indicate that the Nile red label is located in a more hydrophobic environment in acpcPNA–DNA duplexes than in the single-stranded acpcPNA. The different fluorescence properties of the acpcPNA hybrids of complementary DNA and DNA carrying a base insertion are suggestive of different interactions between the Nile red label and the duplexes. PMID:25246975

  18. Mental Status after West Nile Virus Infection

    PubMed Central

    Sadek, Joseph; Pergam, Steven; Echevarria, Leonor A.; Davis, Larry E.; Goade, Diane; Harnar, Joanne; Nofchissey, Robert A.; Sewel, C. Mack; Ettestad, Paul

    2006-01-01

    Mental status after acute West Nile virus infection has not been examined objectively. We compared Telephone Interview for Cognitive Status scores of 116 patients with West Nile fever or West Nile neuroinvasive disease. Mental status was poorer and cognitive complaints more frequent with West Nile neuroinvasive disease (p = 0.005). PMID:16965710

  19. Environmental color affects Nile tilapia reproduction.

    PubMed

    Volpato, G L; Duarte, C R A; Luchiari, A C

    2004-04-01

    We investigated the effects of environmental color on the reproductive behavior of Nile tilapia, Oreochromis niloticus. Two environmental colors were tested by covering the aquarium (60 x 60 x 40 cm) with white (12 groups) or blue (13 groups) cellophane and observing reproductive behavior in groups of 2 males (10.27 +/- 0.45 cm) and 3 females (10.78 +/- 0.45 cm) each. After assignment to the respective environmental color (similar luminosity = 100 to 120 Lux), the animals were observed until reproduction (identified by eggs in the female's mouth) or up to 10 days after the first nest building. Photoperiod was from 6:00 h to 18:00 h every day. Food was offered in excess once a day and water quality was similar among aquaria. Daily observations were made at 8:00, 11:00, 14:00 and 17:00 h regarding: a) latency to the first nest, b) number of nests, c) gravel weight removed (the male excavates the nest in the bottom of the aquarium), d) nest area, and e) mouthbrooding incubation (indication of reproduction). The proportion of reproducing fish was significantly higher (6 of 13) in the group exposed to the blue color compared the group exposed to the white color (1 of 12; Goodman's test of proportions). Moreover, males under blue light removed significantly larger masses of gravel (blue = 310.70 +/- 343.50 g > white = 130.38 +/- 102.70 g; P = 0.01) and constructed wider nests (blue = 207.93 +/- 207.80 cm(2) > white = 97.68 +/- 70.64 cm(2); P = 0.03) than the control (white). The other parameters did not differ significantly between light conditions. We concluded that reproduction in the presence of blue light was more frequent and intense than in the presence of white light.

  20. Economic implications for management of structural retention on harvest units at the Blue River Ranger District, Willamette National Forest, Oregon. Forest Service research note

    SciTech Connect

    Weigand, J.F.; Burditt, A.L.

    1992-06-01

    The paper examines existing knowledge of economic impacts and considers future economic implications and questions about management for stand structural retention in the Blue River Ranger District. It also characterizes the economic outcomes for district-wide timber supply and revenues through calendar year 1990 as a function of management for structural retention, other concurrent policy decisions, and market behavior. The scope of the review is limited in that it draws on only the brief window of time when stand management has incorporated legacies of green trees, snags, and down wood in prescriptions for harvest sales. Anecdotal information is used extensively because much needed information, particularly details on changes in harvesting costs under conditions of structural retention, does not exist in the initial period of transition.

  1. Two-Dimensional Hydrodynamic Modeling and Analysis of the Proposed Channel Modifications and Grade Control Structure on the Blue River near Byram's Ford Industrial Park, Kansas City, Missouri

    USGS Publications Warehouse

    Huizinga, Richard J.

    2007-01-01

    The Blue River Channel Modification project being implemented by the U.S. Army Corps of Engineers (USACE) is intended to provide flood protection within the Blue River valley in the Kansas City, Mo., metropolitan area. In the latest phase of the project, concerns have arisen about preserving the Civil War historic area of Byram's Ford and the associated Big Blue Battlefield while providing flood protection for the Byram's Ford Industrial Park. In 1996, the USACE used a physical model built at the Waterways Experiment Station (WES) in Vicksburg, Miss., to examine the feasibility of a proposed grade control structure (GCS) that would be placed downstream from the historic river crossing of Byram's Ford to provide a subtle transition of flow from the natural channel to the modified channel. The U.S. Geological Survey (USGS), in cooperation with the USACE, modified an existing two-dimensional finite element surface-water model of the river between 63d Street and Blue Parkway (the 'original model'), used the modified model to simulate the existing (as of 2006) unimproved channel and the proposed channel modifications and GCS, and analyzed the results from the simulations and those from the WES physical model. Modifications were made to the original model to create a model that represents existing (2006) conditions between the north end of Swope Park immediately upstream from 63d Street and the upstream limit of channel improvement on the Blue River (the 'model of existing conditions'). The model of existing conditions was calibrated to two measured floods. The model of existing conditions also was modified to create a model that represents conditions along the same reach of the Blue River with proposed channel modifications and the proposed GCS (the 'model of proposed conditions'). The models of existing conditions and proposed conditions were used to simulate the 30-, 50-, and 100-year recurrence floods. The discharge from the calibration flood of May 15, 1990, also

  2. Solar Forcings on Nile and Earthquakes

    NASA Astrophysics Data System (ADS)

    Al-Shehri, Saad Mohammed; Sabbah, Ismail; Yousef, Shahinaz Moustafa; Amin, Magdy Y.

    2013-03-01

    Nile and earthquake periodicities are examined in the light of solar and geomagnetic periodicities in order to uncover the role of the sun in initiating such terrestrial phenomena. The Nile periodicities under considerations covers the period 622-1420 AD. 1749- 1800 and 1870-1945 and are taken from an earlier paper by Yousef and El-Rae (1995). It is found that 11 yr and 21 yr solar periodicities affected the White Nile originating from the Equatorial plateau. On the other hand the Blue Nile arising mainly from Lake Tana in Ethiopia was affected mostly by the 3.3 yr, 2.9 yr, 2.7 yr, and the 2.52 yr periodicities. Such short periodicities are also present in cosmic rays. This is fairly true as during weak solar cycles series at the bottom of the 80-120 year Solar Wolf-Gleissberg Cycles, the level of the second to last of the weak cycles rise and fall coherently with full solar cycles with a correlation coefficient of about 0.9. Rain over Ethiopia is affected by the Monsoon precipitation which is related to the quasi biennial oscillations QBO of the equatorial zonal wind between the easterlies and the westerlies in the tropical stratosphere with a mean period of 29 months. We propose that the QBO are stimulated by the 2.52-2.48 yr solar periodicities. The 2.52 and 2.48 yr periodicity is strong in odd solar cycles 21 and 23. Generally speaking, it looks that different solar periodicities are space-time dependant and that they affect different regimes of terrestrial responses. In the case of earthquakes, we think that they are related to geomagnetic storms initiated by solar stimuli. Several solar periodicities are found in earthquakes. We postulate that electric currents in the ring current and in the ionosphere induce surface as well as deep electric currents in the magma thus produce motion and disturbances of the plates and the magma leading to earthquakes and volcanoes.

  3. Impact of introduced Nile tilapia (Oreochromis niloticus) on non-native aquatic ecosystems.

    PubMed

    Vicente, I S T; Fonseca-Alves, C E

    2013-02-01

    The global invasion of non-native aquatic ecosystems by Nile tilapia (Oreochromis niloticus) is well documented and coincides with their increased use as an aquaculture species. Aquaculture can be defined as the farming of fish or other aquatic organisms and it varies considerably in terms of production practices. Generally, freshwater finfish, such as Nile tilapia, are reared in inland ponds (closed systems). However, in several countries, floating cages are increasingly used to rear Nile tilapia in open water bodies. In such systems, escape is inevitable. The Nile tilapia is considered an omnivorous species and it ingests zooplankton, phytoplankton, or debris present in rivers. As a consequence, the release of Nile tilapia into non-native aquatic ecosystems may result in competition for food and space, thereby damaging native species. The wide environmental tolerance and high reproductive rate of Nile tilapia facilitate its use for aquaculture, but also render the species highly invasive. Here, we review the high frequency of Nile tilapia in non-native biodiversity and indicate the existence of the species under feral conditions in every country in which it has been introduced through farming systems.

  4. Tracking Nile Delta Vulnerability to Holocene Change

    PubMed Central

    Marriner, Nick; Flaux, Clément; Morhange, Christophe; Stanley, Jean-Daniel

    2013-01-01

    Understanding deltaic resilience in the face of Holocene climate change and human impacts is an important challenge for the earth sciences in characterizing the full range of present and future wetland responses to global warming. Here, we report an 8000-year mass balance record from the Nile Delta to reconstruct when and how this sedimentary basin has responded to past hydrological shifts. In a global Holocene context, the long-term decrease in Nile Delta accretion rates is consistent with insolation-driven changes in the ‘monsoon pacemaker’, attested throughout the mid-latitude tropics. Following the early to mid-Holocene growth of the Nile’s deltaic plain, sediment losses and pronounced erosion are first recorded after ~4000 years ago, the corollaries of falling sediment supply and an intensification of anthropogenic impacts from the Pharaonic period onwards. Against the backcloth of the Saharan ‘depeopling’, reduced river flow underpinned by a weakening of monsoonal precipitation appears to have been particularly conducive to the expansion of human activities on the delta by exposing productive floodplain lands for occupation and irrigation agriculture. The reconstruction suggests that the Nile Delta has a particularly long history of vulnerability to extreme events (e.g. floods and storms) and sea-level rise, although the present sediment-starved system does not have a direct Holocene analogue. This study highlights the importance of the world’s deltas as sensitive archives to investigate Holocene geosystem responses to climate change, risks and hazards, and societal interaction. PMID:23922692

  5. Effect of phosphorus fluctuation caused by river water dilution in eutrophic lake on competition between blue-green alga Microcystis aeruginosa and diatom Cyclotella sp.

    PubMed

    Amano, Yoshimasa; Sakai, Yusuke; Sekiya, Takumi; Takeya, Kimitaka; Taki, Kazuo; Machida, Motoi

    2010-01-01

    Tega-numa (Lake Tega) is one of the eutrophic lakes in Japan. For the improvement of water quality in Lake Tega, the North-chiba Water Conveyance Channel was constructed in 2000, which transfer water from Tone River into the lake. After 2000, the dominant species of diatoms, mainly Cyclotella sp., have been replacing blue-green algae, mainly Microcystis aeruginosa in Lake Tega. This transition of dominant species would be due to the dilution, but the detail mechanism has not been understood yet. This study examined the relationship between phosphorus fluctuation caused by river water dilution to Lake Tega and dominance of algal species, M. aeruginosa or Cyclotella sp. based on the single-species and the mixed-species culture experiments. The single-species culture experiment showed that the half-saturation constant and uptake rate of phosphorus were one order lower and seven times higher for M. aeruginosa than those for Cyclotella sp. These findings implied that M. aeruginosa would possess a potential for the growth and survival over Cyclotella sp. in the phosphorus limited condition. The superiority of M. aeruginosa was reflected in the outcome of the mixed-species culture experiment, i.e., dominance of M. aeruginosa, even phosphorus concentration was lowered to 0.01 mg-P/L. Therefore, it could be concluded that the decrease in phosphorus concentration due to the river water dilution to Lake Tega would be interpreted as a minor factor for the transition of dominant species from M. aeruginosa to Cyclotella sp.

  6. Monitoring the Spread of West Nile Virus with Satellite Data

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA-funded study uses temperature and vegetation data from satellites to help track and predict where West Nile virus is spreading in North America. Scientists and public health officials hope one day to use near real-time maps to focus resources and stave off the disease more efficiently. This image is a composite of land surface temperatures (LST) recorded between 1997 and 2000 and was used to help monitor and predict the spread of West Nile virus in the United States. In the color figure above, the mean land surface temperatures are in red; annual amplitude-or the difference between low and high annual temperatures-is in blue; and annual phase-or the timing of annual temperature peaks-appears in green. Brighter colors mean higher values. The major north-south temperature difference (dull red in the upper part of the image to bright red in the lower part) is considerably affected by the Rockies in the west and to a much lesser extent by the Appalachians in the east. The brighter blue in the upper part of the image indicates the big difference between highest and lowest temperatures during the course of a year at higher latitudes. There is less variation in the timing of the annual peak of land surface temperatures, which occurs earlier in the south than in the north. Black dots superimposed on this image are the locations (county geo-centers) where birds infected with West Nile virus were reported between January and October 2001. Scientists working with the International Research Partnership for Infectious Diseases (INTREPID) program based at NASA are using such imagery to define and predict the conditions where mosquitoes transmit West Nile virus in the U.S. The conclusion reached about the importance of any single variable depends both upon its value and context. A temperature of 30o Celsius (86o Fahrenheit) might be fatal for a mosquito at low humidity but survivable at higher humidities. The work done here on West Nile virus and other diseases shows very

  7. Monitoring the Spread of West Nile Virus with Satellite Data

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA-funded study uses temperature and vegetation data from satellites to help track and predict where West Nile virus is spreading in North America. Scientists and public health officials hope one day to use near real-time maps to focus resources and stave off the disease more efficiently. This image is a composite of land surface temperatures (LST) recorded between 1997 and 2000 and was used to help monitor and predict the spread of West Nile virus in the United States. In the color figure above, the mean land surface temperatures are in red; annual amplitude-or the difference between low and high annual temperatures-is in blue; and annual phase-or the timing of annual temperature peaks-appears in green. Brighter colors mean higher values. The major north-south temperature difference (dull red in the upper part of the image to bright red in the lower part) is considerably affected by the Rockies in the west and to a much lesser extent by the Appalachians in the east. The brighter blue in the upper part of the image indicates the big difference between highest and lowest temperatures during the course of a year at higher latitudes. There is less variation in the timing of the annual peak of land surface temperatures, which occurs earlier in the south than in the north. Black dots superimposed on this image are the locations (county geo-centers) where birds infected with West Nile virus were reported between January and October 2001. Scientists working with the International Research Partnership for Infectious Diseases (INTREPID) program based at NASA are using such imagery to define and predict the conditions where mosquitoes transmit West Nile virus in the U.S. The conclusion reached about the importance of any single variable depends both upon its value and context. A temperature of 30o Celsius (86o Fahrenheit) might be fatal for a mosquito at low humidity but survivable at higher humidities. The work done here on West Nile virus and other diseases shows very

  8. West Nile Virus

    PubMed Central

    Rossi, Shannan L.; Ross, Ted M.; Evans, Jared D.

    2010-01-01

    Overview Since its isolation in Uganda in 1937, West Nile virus (WNV) has been responsible for thousands of cases of morbidity and mortality in birds, horses, and humans. Historically, epidemics were localized to Europe, Africa, the Middle East, and parts of Asia, and primarily caused a mild febrile illness in humans. However, in the late 1990’s, the virus became more virulent and expanded its geographical range to North America. In humans, the clinical presentation ranges from asymptomatic (approximately 80% of infections) to encephalitis/paralysis and death (less than 1% of infections). There is no FDA-licensed vaccine for human use, and the only recommended treatment is supportive care. Individuals that survive infection often have a long recovery period. This article will review the current literature summarizing the molecular virology, epidemiology, clinical manifestations, pathogenesis, diagnosis, treatment, immunology, and protective measures against WNV and WNV infections in humans. PMID:20513541

  9. Mutually beneficial and sustainable management of Ethiopian and Egyptian dams in the Nile Basin

    NASA Astrophysics Data System (ADS)

    Habteyes, Befekadu G.; Hasseen El-bardisy, Harb A. E.; Amer, Saud A.; Schneider, Verne R.; Ward, Frank A.

    2015-10-01

    Ongoing pressures from population growth, recurrent drought, climate, urbanization and industrialization in the Nile Basin raise the importance of finding viable measures to adapt to these stresses. Four tributaries of the Eastern Nile Basin contribute to supplies: the Blue Nile (56%), White Nile-Albert (14%), Atbara (15%) and Sobat (15%). Despite much peer reviewed work addressing conflicts on the Nile, none to date has quantitatively examined opportunities for discovering benefit sharing measures that could protect negative impacts on downstream water users resulting from new upstream water storage developments. The contribution of this paper is to examine the potential for mutually beneficial and sustainable benefit sharing measures from the development and operation of the Grand Ethiopian Renaissance Dam while protecting baseline flows to the downstream countries including flows into the Egyptian High Aswan Dam. An integrated approach is formulated to bring the hydrology, economics and institutions of the region into a unified framework for policy analysis. A dynamic optimization model is developed and applied to identify the opportunities for Pareto Improving measures to operate these two dams for the four Eastern Nile Basin countries: Ethiopia, South Sudan, Sudan, and Egypt. Results indicate a possibility for one country to be better off (Ethiopia) and no country to be worse off from a managed operation of these two storage facilities. Still, despite the optimism of our results, considerable diplomatic negotiation among the four riparians will be required to turn potential gains into actual welfare improvements.

  10. National Dam Inspection Program. Blue Mountain Lake Dam (NDI ID PA 00627, PA DER 45-34), Delaware River Basin, Unnamed Tributary of Brodhead Creek, Pennsylvania. Phase I Inspection Report

    DTIC Science & Technology

    1981-08-01

    mounood [ ,3Q,,s’t,lt l oo &I on .. .. .+ MCCR DELAWARE RIVER BASIN Avallability Co4e _Avail- and/tim’eor - 11As pecial8J BLUE MOUNTAIN LAKE DAM...concrete reservoir outlet pipe discharges into the spillway channel about 50 feet downstream of the embankment. The inlet gate, which is located in the...impoundment at the upstream end of the pipe , is no longer operable. b. Lncation. Blue Mountain Lake Dam is located on a branch of Ruliffs Run, about 2.5

  11. Identification of impacts on the Egyptian Nile using remote sensing and GIS

    NASA Astrophysics Data System (ADS)

    El-Nahry, A. H.

    2013-10-01

    Nile River, the longest river in the world, 6,695 km long from its remotest headstream, the Luvironza River in Burundi, central Africa, to its delta on the Mediterranean Sea, NE Egypt. The Nile River islands form an attractive agricultural area characterized with its nightly fertile soils, easy source, and its suitability to a wide range of land use. The present use of these Nile islands does not reach the maximum capability of these resources due to improper land use of these areas.The current study aims at identifying the changes of the Nile course and its islands during the last three decades using remote sensing and GIS techniques in order to provide the scientific bases, which help in planning the most suitable programs of land use, soil management and conservation. Six MSS, eight TM and Eight ETM+ satellite images dated to 1972,1984 and 2002 respectively were used to study the changes occurred during the above-mentioned periods. The study area was divided into five sectors along the Nile River course i.e. Aswan - Qena, Qena - Assiut , Assiut - Qalubia , Qalubia - Damietta and Qalubia - Rosetta . The changes in Nile course from early seventieth to middle eighteenth were decreased by 51.34 Km2, from middle eighteenth to the millennium were decreased by 40.30 Km2. The overall change in Nile course area decreased by 91.64 Km2 in the investigation period. Belonging to the islands number and their areas in the investigation period, the changes in islands number from early seventieth to middle eighteenth were increased by 171 islands, from middle eighteenth to the millennium were decreased by 86 islands. Meanwhile, the islands areas from early seventieth to middle eighteenth were decreased by 4512.39 Feddan., from middle eighteenth to the millennium were decreased by 5446.97 Feddan. The overall change in the investigation period for the total number of the islands was increased by 85 islands, meanwhile the islands areas were decreased by 9959.36 Feddan. Changes of

  12. Habitat use and population characteristics of potentially spawning shovelnose sturgeon Scaphirhynchus platorynchus (Rafinesque, 1820), blue sucker ( Cycleptus elongatus (Lesueur, 1817), and associated species in the lower Wisconsin River, USA

    DOE PAGES

    Lyons, John D.; Walchak, D.; Haglund, J.; ...

    2016-11-07

    The goal of this study was to compare the possible locations, timing, and characteristics of potentially spawning shovelnose sturgeon (Scaphirhynchus platorynchus), blue sucker (Cycleptus elongatus), and associated species during the spring of 2007-2015 in the 149-km-long lower Wisconsin River, Wisconsin, USA, a large, shallow, sand-dominated Mississippi River tributary. A 5-km index station of two pairs of rocky shoals surrounded by sandy areas was electrofished for shovelnose sturgeon and blue sucker in a standardized fashion a total of 40 times from late March through mid- June, the presumed spawning period. On one date in 2008 and two dates in 2012, allmore » rocky shoals and adjacent sandy areas in the lowermost 149 km of the river were also electrofished for both species. Shovelnose sturgeon and blue sucker appeared to spawn in the limited rocky areas of the river along with at least four other species: mooneye (Hiodon tergisus), quillback (Carpiodes cyprinus), smallmouth buffalo (Ictiobus bubalus), and shorthead redhorse (Moxostoma macrolepidotum), usually at depths of 0.8-2.0 m and surface velocities of 0.4–1.0 m/s. However, apparently spawning shovelnose sturgeon were found only on mid-channel cobble and coarse gravel shoals within a single 7-km segment that included the 5-km index station, whereas apparently spawning blue suckers were encountered on these same shoals but also more widely throughout the river on eroding bluff shorelines of bedrock and boulder and on artificial boulder wing dams and shoreline rip-rap. Both species showed evidence of homing to the same mid-channel shoal complexes across years.« less

  13. Petrology and U-PB geochronology of the Robertson River Igneous Suite, Blue Ridge province, Virginia - Evidence for multistage magmatism associated witn an early episode of Laurentian rifting

    USGS Publications Warehouse

    Tollo, R.P.; Aleinikoff, J.N.

    1996-01-01

    The Late Neoproterozoic (735-702 Ma) Robertson River Igneous Suite includes at least eight plutons ranging in composition from syenogranite to alkali feldspar granite to alkali feldspar syenite. These plutons intruded Mesoproterozoic (1.2-1.0 Ga) gneissic basement of the Blue Ridge anticlinorium in northern and central Virginia during an early episode of Laurentian rifting. Robertson River plutons range in composition from metaluminous to peralkaline and, relative to other granite types, exhibit compositional characteristics of A-type granitoids including (1) marked enrichment in Nb, Zr, Y, REE (except Eu), and Ga, (2) high Ga/Al and FeO(total)/MgO, and (3) depletion of Ba and Sr. High Ga/Al ratios are particularly diagnostic of the suite and serve as an effective discriminant between originally metaluminous and peralkaline bulk compositions, providing a useful proxy for widely used indicators based on major elements that are prone to remobilization. U-Pb isotopic analyses of zircons indicate that the suite was emplaced in two pulses, occurring at 735 to 722 and 706 to 702 Ma. Metaluminous magmas were emplaced during both pulses, formed most of the main batholith, and fractionated as independent, time-correlative groups. Peralkaline magmas were emplaced only during the final pulse, formed a volcanic center that erupted unknown quantities of rhyolite, and experienced a style of fractionation similar to the metaluminous types. Differences in Ce/Nb, Y/Nb, and Yb/Ta ratios suggest that the metaluminous and peralkaline magmas were derived from different sources. The Robertson River Igneous Suite is part of a regional group of Late Neoproterozoic (760-700 Ma) plutons including at least 20 other A-type granitoid bodies exposed throughout the Laurentian terrane of Virginia and northwestern North Carolina. Like the Robertson River, most of the other granitoids are metaluminous in composition, typically form multi-intrusive, elongate plutons, and are not geographically

  14. Control Over the Nile: Implications across Nations

    DTIC Science & Technology

    2010-06-01

    Declaration...................................................................50 3. The Hydro-Meteorological Survey of the Equatorial Lakes ( HYDROMET ...Eastern Nile Subsidiary Action Program HYDROMET Hydro-Meteorological Survey of the Equatorial Lakes IMF International Monetary Fund NBI Nile...The Hydro-Meteorological Survey of the Equatorial Lakes ( HYDROMET ) Led by Egypt, the Nile basin countries of Kenya, Uganda, Tanzania, and Sudan

  15. Antibody response of five bird species after vaccination with a killed West Nile virus vaccine.

    PubMed

    Okeson, Danelle M; Llizo, Shirley Yeo; Miller, Christine L; Glaser, Amy L

    2007-06-01

    West Nile virus has been associated with numerous bird mortalities in the United States since 1999. Five avian species at three zoological parks were selected to assess the antibody response to vaccination for West Nile virus: black-footed penguins (Spheniscus demersus), little blue penguins (Eudyptula minor), American flamingos (Phoenicopterus ruber), Chilean flamingos (Phoenicopterus chilensis), and Attwater's prairie chickens (Tympanuchus cupido attwateri). All birds were vaccinated intramuscularly at least twice with a commercially available inactivated whole virus vaccine (Innovator). Significant differences in antibody titer over time were detected for black-footed penguins and both flamingo species.

  16. Climate Change Effects on Respiration Rates of Blue Crab (Callinectes sapidus) from the Patuxent River, Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Nyffeler, A.

    2016-02-01

    A rise in atmospheric CO2 induces a greenhouse effect that also causes ocean temperatures and CO2 levels to rise. These environmental changes may represent an additional energetic cost for blue crabs because they rely on the concentration of CO2 in the water to deposit calcium carbonate in their shells. We conducted a respiration experiment to measure the effect of climate change on crab metabolism. Crabs were collected from the Chesapeake Bay and exposed to different heated and acidified conditions. After crabs had been exposed to the environmental conditions in the chambers for two molts, they were placed in respiration chambers to measure rates of oxygen consumption. Results indicated different trends in respiration rates between the treatments, although the patterns were not statistically significant. Crabs exposed to higher temperatures showed elevated respiration rates, while crabs exposed to high CO2 demonstrated decreased respiration rates. The two factors of climate change (high temperature and high CO2) did not demonstrate the highest respiration rate, but rather the crabs exposed to high temperatures and ambient CO2 showed the highest mean respiration rate. These data suggest that crab metabolism may not change as much as expected due to climate changes.

  17. A giant dune-dammed lake on the North Platte River, Nebraska

    SciTech Connect

    Swinehart, J.B. . Conservation and Survey Div.); Loope, D.B. . Dept. of Geology)

    1992-01-01

    The recent work in the Nebraska Sand Hills, just north of the North Platte Valley, has revealed the presence of numerous dune dams--sites where eolian sand has filled Pleistocene paleovalleys and caused the formation of lake basins containing abundant small, interdunal lakes. Although the Platte River is considered the southern margin of the Sand Hills, there is a 1,200 sq km triangular area of large dunes in Lincoln County just south of the South Platte. The authors hypothesize that large dunes migrated southward to fill the North Platte Valley during glacial maximum when both the North and South Platte were dry. As Rocky Mountain snowmelt and Great Plains precipitation increased during deglaciation, a single 65 km-long, 15 km-wide, 50 m-deep lake formed behind the massive dune dam. The tentative chronology suggests that the lake was in existence for at least several thousand years. They have not yet found compelling evidence of catastrophic flooding downstream of the former lake. Evidence of two large Quaternary lakes on the White Nile between Khartoum and Malakal (Sudan) was discovered in the 1960's. Shoreline deposits indicate the lakes were 400--600 km long and up to 50 km wide. Although the lakes have been attributed to repeated blockage of the White Nile by clay-rich Blue Nile deposits, the distribution and age of dune sand near the confluence of these rivers suggest that, as in the Nebraska example, the course of the White Nile was blocked by dunes when the region was desiccated in the Late Pleistocene. Lakes behind permeable dams rise to a level where input equals output. Earthen dams are vulnerable to overtopping and piping. The relatively high permeability of dune sand prevents or delays overtopping, and piping is prevented by the extremely high low hydraulic gradients that typify extant sand dams.

  18. Effects of wastewater effluent discharge and treatment facility upgrades on environmental and biological conditions of the upper Blue River, Johnson County, Kansas and Jackson County, Missouri, January 2003 through March 2009

    USGS Publications Warehouse

    Graham, Jennifer L.; Stone, Mandy L.; Rasmussen, Teresa J.; Poulton, Barry C.

    2010-01-01

    The Johnson County Blue River Main Wastewater Treatment Facility discharges into the upper Blue River near the border between Johnson County, Kansas and Jackson County, Missouri. During 2005 through 2007 the wastewater treatment facility underwent upgrades to increase capacity and include biological nutrient removal. The effects of wastewater effluent on environmental and biological conditions of the upper Blue River were assessed by comparing an upstream site to two sites located downstream from the wastewater treatment facility. Environmental conditions were evaluated using previously and newly collected discrete and continuous data, and were compared with an assessment of biological community composition and ecosystem function along the upstream-downstream gradient. This evaluation is useful for understanding the potential effects of wastewater effluent on water quality, biological community structure, and ecosystem function. In addition, this information can be used to help achieve National Pollution Discharge Elimination System (NPDES) wastewater effluent permit requirements after additional studies are conducted. The effects of wastewater effluent on the water-quality conditions of the upper Blue River were most evident during below-normal and normal streamflows (about 75 percent of the time), when wastewater effluent contributed more than 20 percent to total streamflow. The largest difference in water-quality conditions between the upstream and downstream sites was in nutrient concentrations. Total and inorganic nutrient concentrations at the downstream sites during below-normal and normal streamflows were 4 to 15 times larger than at the upstream site, even after upgrades to the wastewater treatment facility were completed. However, total nitrogen concentrations decreased in wastewater effluent and at the downstream site following wastewater treatment facility upgrades. Similar decreases in total phosphorus were not observed, likely because the biological

  19. Food chain sources of polychlorinated dioxins and furans to great blue herons, ardea herodias, foraging in the fraser river estuary, british columbia. Technical report series no. no. 169

    SciTech Connect

    1995-12-01

    This paper presents results of determinations of polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF) levels in the prey of great blue herons foraging on the Fraser River estuary tidal flats. Observations of herons foraging at Iona and Westham Islands showed that starry flounder (Platichthys stellatus) and Pacific staghorn sculpin (Leptocottus armatus) were the major prey species throughout the year. The paper includes measurements of PCDD/PCDF levels in those two species and others such as redside shiner (Richardsonius balteatus), peamouth chub (Mylocheilus caurinum), and shiner perch (Cymatogaster aggregata). The paper concludes with a discussion of the role of contaminated inshore fish on the entry of PCDD/PCDF into herons.The purpose of the Ecological Monitoring and Assessment Network is to provide information and understanding needed for the sustainable management of Canada`s resources and resource-based industries. This document presents the proceedings of the first meeting of the Network. It includes presentations by federal government representatives on ecological monitoring and research programs in federal departments, reviews of progress in establishing Ecological Science Cooperatives for ecological monitoring and research, presentations on topical workshops, and workshop summaries. The workshops were arranged by ecological issue (biodiversity, climate change, ultraviolet radiation, toxic chemicals, and cumulative effects). They discussed and recommended local and national goals, objectives, and deliverables for ongoing research, monitoring, and synthesis related to the ecological effects of each issue.

  20. [West Nile virus infection].

    PubMed

    Pérez Ruiz, Mercedes; Gámez, Sara Sanbonmatsu; Clavero, Miguel Angel Jiménez

    2011-12-01

    West Nile virus (WNV) is an arbovirus usually transmitted by mosquitoes. The main reservoirs are birds, although the virus may infect several vertebrate species, such as horses and humans. Up to 80% of human infections are asymptomatic. The most frequent clinical presentation is febrile illness, and neuroinvasive disease can occur in less than 1% of cases. Spain is considered a high-risk area for the emergence of WNV due to its climate and the passage of migratory birds from Africa (where the virus is endemic). These birds nest surrounding wetlands where populations of possible vectors for the virus are abundant. Diagnosis of human neurological infections can be made by detection of IgM in serum and/or cerebrospinal fluid samples, demonstration of a four-fold increase in IgG antibodies between acute-phase and convalescent-phase serum samples, or by detection of viral genome by reverse transcription-polymerase chain reaction (especially useful in transplant recipients). Since WNV is a biosafety level 3 agent, techniques that involve cell culture are restricted to laboratories with this level of biosafety, such as reference laboratories. The National Program for the Surveillance of WNV Encephalitis allows the detection of virus circulation among birds and vectors in areas especially favorable for the virus, such as wetlands, and provides information for evaluation of the risk of disease in horses and humans.

  1. An ancient icon reveals new mysteries: mummy DNA resurrects a cryptic species within the Nile crocodile.

    PubMed

    Hekkala, Evon; Shirley, Matthew H; Amato, George; Austin, James D; Charter, Suellen; Thorbjarnarson, John; Vliet, Kent A; Houck, Marlys L; Desalle, Rob; Blum, Michael J

    2011-10-01

    The Nile crocodile (Crocodylus niloticus) is an ancient icon of both cultural and scientific interest. The species is emblematic of the great civilizations of the Nile River valley and serves as a model for international wildlife conservation. Despite its familiarity, a centuries-long dispute over the taxonomic status of the Nile crocodile remains unresolved. This dispute not only confounds our understanding of the origins and biogeography of the 'true crocodiles' of the crown genus Crocodylus, but also complicates conservation and management of this commercially valuable species. We have taken a total evidence approach involving phylogenetic analysis of mitochondrial and nuclear markers, as well as karyotype analysis of chromosome number and structure, to assess the monophyletic status of the Nile crocodile. Samples were collected from throughout Africa, covering all major bioregions. We also utilized specimens from museum collections, including mummified crocodiles from the ancient Egyptian temples at Thebes and the Grottes de Samoun, to reconstruct the genetic profiles of extirpated populations. Our analyses reveal a cryptic evolutionary lineage within the Nile crocodile that elucidates the biogeographic history of the genus and clarifies long-standing arguments over the species' taxonomic identity and conservation status. An examination of crocodile mummy haplotypes indicates that the cryptic lineage corresponds to an earlier description of C. suchus and suggests that both African Crocodylus lineages historically inhabited the Nile River. Recent survey efforts indicate that C. suchus is declining or extirpated throughout much of its distribution. Without proper recognition of this cryptic species, current sustainable use-based management policies for the Nile crocodile may do more harm than good. © 2011 Blackwell Publishing Ltd.

  2. [Maternity blues].

    PubMed

    Gonidakis, F

    2007-04-01

    Maternity blues is a transient change of mood that occurs mainly between the 1st and 10th day of puerpartum and is characterized by bursts of tears, mild depressive mood, anxiety and liability of mood. The frequency of maternity blues varies in different studies form 4% to 80%. A number of biological and psychosocial parameters have been studied in order to determine their correlation with maternity blues. The most well studied biological parameters are progesterone and cortizol although their relation with maternity blues has not yet been clearly defined. Stress and the emotional state of the woman during pregnancy as well as history of mood disorders or maternity blues in a previous birth are the psychosocial parameters that are more likely to correlate with the occurrence of maternity blues. Most of the authors suggest that information on maternity blues and reassurance of the woman are the best way to deal with maternity blues both on preventive and therapeutical basis.

  3. Understanding the hydrologic sources and sinks in the Nile Basin using multisource climate and remote sensing data sets

    NASA Astrophysics Data System (ADS)

    Senay, Gabriel B.; Velpuri, Naga Manohar; Bohms, Stefanie; Demissie, Yonas; Gebremichael, Mekonnen

    2014-11-01

    In this study, we integrated satellite-drived precipitation and modeled evapotranspiration data (2000-2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. Over 2000-2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile Basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual timescales, the Nile Basin storage change is substantial while over longer time periods, it is minimal (<1% of basin precipitation). We also used long-term gridded runoff and river discharge data (1869-1984) to understand the discrepancy in the observed and expected flow along the Nile River. The top three countries that contribute most to the flow are Ethiopia, Tanzania, and Kenya. The study revealed that ˜85% of the runoff generated in the equatorial region is lost in an interstation basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the literature reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is greater (97 km3) than the reported amount (84 km3). Due to the large variations of the reported Nile flow at different locations and time periods, the study results indicate the need for increased hydrometeorological instrumentation of the basin. The study also helped improve our understanding of the spatial dynamics of water sources and sinks in the Nile Basin and identified emerging hydrologic questions that require further attention.

  4. Understanding the hydrologic sources and sinks in the Nile Basin using multisource climate and remote sensing data sets

    USGS Publications Warehouse

    Senay, Gabriel; Velpuri, Naga Manohar; Bohms, Stefanie; Demissie, Yonas; Gebremichael, Mekonnen

    2014-01-01

    In this study, we integrated satellite-drived precipitation and modeled evapotranspiration data (2000–2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. Over 2000–2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile Basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual timescales, the Nile Basin storage change is substantial while over longer time periods, it is minimal (<1% of basin precipitation). We also used long-term gridded runoff and river discharge data (1869–1984) to understand the discrepancy in the observed and expected flow along the Nile River. The top three countries that contribute most to the flow are Ethiopia, Tanzania, and Kenya. The study revealed that ∼85% of the runoff generated in the equatorial region is lost in an interstation basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the literature reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is greater (97 km3) than the reported amount (84 km3). Due to the large variations of the reported Nile flow at different locations and time periods, the study results indicate the need for increased hydrometeorological instrumentation of the basin. The study also helped improve our understanding of the spatial dynamics of water sources and sinks in the Nile Basin and identified emerging hydrologic questions that require further attention.

  5. Rivers

    USGS Publications Warehouse

    Leopold, Luna Bergere

    1962-01-01

    Rivers are both the means and the routes by which the products of continental weathering are carried to the oceans of the world. Except in the most arid areas more water falls as precipitation than is lost by evaporation and transpiration from the land surface to the atmosphere. Thus there is an excess of water, which must flow to the ocean. Rivers, then, are the routes by which this excess water flows to the ultimate base level. The excess of precipitation over evaporation and transpiration provides the flow of rivers and springs, recharges ground-water storage, and is the supply from which man draws water for his needs.

  6. Integrating Blue Carbon Initiatives with the Management of Wildlife Cobenefits: a Case Study at the Nisqually River Delta, WA

    NASA Astrophysics Data System (ADS)

    Woo, I.; De La Cruz, S.; Windham-Myers, L.; Thorne, K.; Drexler, J. Z.; Byrd, K. B.; Bergamaschi, B. A.; Davis, M.; Anderson, F. E.; Ballanti, L.; Zhu, Z.; Schmerfeld, J.; Johnson, K.; Nakai, G.

    2016-12-01

    Carbon transport, cycling, and storage within coastal wetlands are amongst the most fundamental processes that support estuarine ecosystem services. In addition to providing habitat and trophic support for wildlife populations and fisheries, coastal wetlands accumulate and store carbon at significant rates. By capturing and storing carbon in soils, coastal wetland can play a vital role in offsetting greenhouse gasses, thereby helping mitigate the impacts of climate change. Estuarine restoration has significant potential to simultaneously increase carbon sequestration and ecosystem functioning for wildlife, linking traditional objectives of protecting, restoring, and managing diverse wetlands to support a broad array of species and their habitats with carbon sequestration initiatives. The Nisqually River Delta is the largest wetland restoration in the Pacific Northwest and is an ideal site to document the carbon co-benefits of a restoring and natural marsh. We compared the sources of carbon that enter food webs to carbon that has accumulated in soils. Juvenile Chinook foodwebs incorporated freshwater/brackish as well as estuarine-derived carbon sources. Soil carbon inputs reflected relatively recent estuarine restoration and a century of diked agricultural and fallow field land use history. A Net Ecosystem Carbon Balance will use EC flux towers to quantify CO2 and CH4 atmospheric flux and constrain aqueous dissolved carbon flux in channels. Ultimately, we will assess the resiliency of tidal marsh under past, present, and future sediment delivery scenarios. Past and present sedimentation data will be analyzed from our soil cores. Future scenarios incorporating potential management strategies to increase sediment delivery onto the delta will be leveraged with existing studies of hydrodynamics and sedimentation models. These scenarios will be used as model inputs to assess the viability of marshes as a result of prospective management strategies and sea-level rise

  7. New insights into hydrologic sources and sinks in the Nile Basin: A multi-source satellite data analysis

    NASA Astrophysics Data System (ADS)

    Senay, G. B.; Velpuri, N. M.; Bohms, S.; Demissie, Y.; Gebremichael, M.

    2014-12-01

    The Nile River is the longest in the world with a length of 6,800 km. However, the contrast between the length of the river or the size of the basin and the comparatively small volume of basin runoff generated is a unique feature of the Nile Basin. Due to non-availability of in-situ hydrologic data, we do not clearly understand the spatial distribution of hydrologic sources and sinks and how much they control input-output dynamics? In this study, we integrated satellite-derived precipitation, and modeled evapotranspiration data (2000-2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. We also used long-term gridded runoff and river discharge data (1869-1984) to understand the discrepancy in the observed and expected flow along the Nile River. Results indicate that over 2000-2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. The top three countries that contribute most to the flow are Ethiopia, Tanzania and Kenya. The study revealed that ~85% of the runoff generated in the Equatorial region is lost in an inter-station basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is larger (97 km3) than the reported amount (84 km3). Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual time-scales, the Nile Basin shows storage change is substantial while over longer-time periods, it is minimal (<1% of basin precipitation

  8. Tissue-based risk assessment of great blue heron (Ardea herodias) exposed to PCDD/DF in the Tittabawassee River floodplain, Michigan, USA.

    PubMed

    Seston, Rita M; Fredricks, Timothy B; Tazelaar, Dustin L; Coefield, Sarah J; Bradley, Patrick W; Newsted, John L; Kay, Denise P; Fitzgerald, Scott D; Giesy, John P; Zwiernik, Matthew J

    2010-11-01

    Concentrations of dioxin-like compounds, primarily polychlorinated dibenzofurans (PCDFs), in soils and sediments of the Tittabawassee River (TR) and associated floodplains downstream of Midland, Michigan, USA, were greater than upstream sites and prompted a site-specific risk assessment of great blue herons (GBH). Tissue exposure of PCDF and polychlorinated dibenzo-p-dioxins (PCDDs) was assessed in multiple GBH tissue types, including blood plasma of adults and eggs, as well as blood plasma, adipose, liver, and muscle of nestlings. Adult GBH exposure was associated with foraging area and age class, with concentrations of PCDD/DF being greater in blood plasma of adult GBH foraging in the TR compared with those foraging in upstream reference areas and in older birds as compared with their younger cohorts. Concentrations of PCDD/DFs and dioxin-like polychlorinated biphenyls (PCBs) in eggs and nestling tissues of GBH collected from rookeries within the TR floodplain were generally similar among rookeries. Mean concentrations of PCDD/DFs in eggs of GBH ranged from 45 to 67 ng/kg, wet weight for the rookeries studied, with a maximum concentration of 210 ng/kg, wet weight observed. Adipose consistently had the greatest concentration of PCDD/DFs of all tissues collected from nestlings of GBH, ranging from 98 to 430 ng/kg, wet weight. Potential for adverse population-level effects from site-specific contaminant exposures were evaluated by comparison with selected toxicity reference values (TRVs). Minimal risk of adverse population-level effects were predicted when exposures measured in tissues of GBH collected from rookeries within the TR were compared with appropriate TRVs. This prediction is consistent with site-specific measures of population condition, which included clutch size and number of nestlings per successful nest.

  9. Water in the face of afforestation in the Nile Basin (Invited)

    NASA Astrophysics Data System (ADS)

    Gebrehiwot, S. G.

    2013-12-01

    Abstract The Nile is the longest river in the world with catchment area of more than 3 × 106 km2 that is home to a fast growing population of some 2 × 107 people. The specific runoff of the River Nile is far less than that of other major world rivers. Much of the rain falling on the catchment, ca 86%, is lost to evapotranspiration which in turn account for the relatively low specific runoff. Afforestation in the Nile Basin is one the major developmental activities in Africa with more than 80% the continent's tree plantation located in the basin. National and continental greening programs, biofuel production, land acquisition and carbon trade are some of the reasons behind the large scale afforestation. Given the complex relationship between forests and water availability, afforestation program needs to give proper consideration to their influence on water availability. Background studies in the Basin indicate that the low flow is highly dependent on the availability of grassland and woodland land covers; while the concurrent biofuel plantation and land investments have been carried out in the areas of grasslands and woodlands, as remote sensing analysis shown. The same studies on the Basin, as well as other studies from similar areas elsewhere in the world suggest that forest impacts on hydrology tend to be localized, where there may also be regional climatic impacts. So, afforestation programs in the Nile Basin need to embrace local impacts with special focus to grasslands and woodlands.

  10. The Holocene Geoarchaeology of the Desert Nile in Northern Sudan

    NASA Astrophysics Data System (ADS)

    Woodward, Jamie; Macklin, Mark; Spencer, Neal; Welsby, Derek; Dalton, Matthew; Hay, Sophie; Hardy, Andrew

    2016-04-01

    Invited Paper Forty years ago Colin Renfrew declared that "every archaeological problem starts as a problem in geoarchaeology" (Renfrew, 1976 p. 2). With this assertion in mind, this paper draws upon the findings from field research in two sectors of the Nile Valley of Northern Sudan dedicated to the exploration of human-environment interactions during the middle and late Holocene. This part of the Nile corridor contains a rich cultural record and an exceptionally well preserved Holocene fluvial archive. A distinctive feature of these records is the variety of evidence for interaction between desert and river over a range of spatial and temporal scales. This interaction presented both challenges and opportunities for its ancient inhabitants. This paper will present evidence for large-scale landscape changes driven by shifts in global climate. It will also show how we have integrated the archaeological and geological records in the Northern Dongola Reach and at Amara West - where long-term field projects led by archaeologists from the British Museum have recognised the importance of a sustained commitment to interdisciplinary research to achieve a fully integrated geoarchaeological approach across a range of scales. The former project is a large-scale landscape survey with multiple sites across an 80 km reach of the Nile whilst the latter has a strong focus on a single New Kingdom town site and changes in its environmental setting. By combining multiple archaeological and geological datasets - and pioneering the use of OSL dating and strontium isotope analysis in the Desert Nile - we have developed a new understanding of human responses to Holocene climate and landscape change in this region. Renfrew, C. (1976) Archaeology and the earth sciences. In: D.A. Davidson and M.I. Shackley (eds) Geoarchaeology: Earth Science and the Past, Duckworth, London, 1-5.

  11. Blue Note

    ScienceCinema

    Murray Gibson

    2016-07-12

    Argonne's Murray Gibson is a physicist whose life's work includes finding patterns among atoms. The love of distinguishing patterns also drives Gibson as a musician and Blues enthusiast."Blue" notes are very harmonic notes that are missing from the equal temperament scale.The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting.

  12. Blue Note

    SciTech Connect

    Murray Gibson

    2007-04-27

    Argonne's Murray Gibson is a physicist whose life's work includes finding patterns among atoms. The love of distinguishing patterns also drives Gibson as a musician and Blues enthusiast."Blue" notes are very harmonic notes that are missing from the equal temperament scale.The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting.

  13. The monoamine oxidase inhibition properties of selected structural analogues of methylene blue.

    PubMed

    Delport, Anzelle; Harvey, Brian H; Petzer, Anél; Petzer, Jacobus P

    2017-06-15

    The thionine dye, methylene blue (MB), is a potent inhibitor of monoamine oxidase (MAO) A, a property that may, at least in part, mediate its antidepressant effects in humans and animals. The central inhibition of MAO-A by MB has also been linked to serotonin toxicity (ST) which may arise when MB is used in combination with serotonergic drugs. Structural analogues and the principal metabolite of MB, azure B, have also been reported to inhibit the MAO enzymes, with all compounds exhibiting specificity for the MAO-A isoform. To expand on the structure-activity relationships (SARs) of MAO inhibition by MB analogues, the present study investigates the human MAO inhibition properties of five MB analogues: neutral red, Nile blue, new methylene blue, cresyl violet and 1,9-dimethyl methylene blue. Similar to MB, these analogues also are specific MAO-A inhibitors with cresyl violet (IC50=0.0037μM), Nile blue (IC50=0.0077μM) and 1,9-dimethyl methylene blue (IC50=0.018μM) exhibiting higher potency inhibition compared to MB (IC50=0.07μM). Nile blue also represents a potent MAO-B inhibitor with an IC50 value of 0.012μM. From the results it may be concluded that non-thionine MB analogues (e.g. cresyl violet and Nile blue) also may exhibit potent MAO inhibition, a property which should be considered when using these compounds in pharmacological studies. Benzophenoxazines such as cresyl violet and Nile blue are, similar to phenothiazines (e.g. MB), representative of high potency MAO-A inhibitors with a potential risk of ST. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Vertical transmission of microcystins to Nile crocodile (Crocodylus niloticus) eggs.

    PubMed

    Singo, Alukhethi; Myburgh, Jan G; Laver, Peter N; Venter, Elizabeth A; Ferreira, Gezina C H; Rösemann, Gertruida M; Botha, Christo J

    2017-08-01

    Cyanobacteria or blue green algae are known for their extensive and highly visible blooms in eutrophic, stagnant freshwater bodies. Climate change and global warming have also contributed to a rise in toxic cyanobacterial blooms. One of the most important cyanobacteria is Microcystis aeruginosa, which can synthesize various microcystins that can affect the health of terrestrial and aquatic animals. Commercial Nile crocodile (Crocodylus niloticus) farming in South Africa is based on keeping breeders (adult males and females) in big dams on farms (captive-bred approach). Unfortunately, cyanobacterial blooms in the breeder dams are a concern to farm owners, managers and veterinarians. The main objectives of this research project were to determine if microcystins were present in the contents of crocodile eggs and the liver and yolk of dead hatchlings, and to determine if the reduced hatchability on commercial farms might be caused by these toxins. Furthermore, the concentration of microcystins in the breeder dam was monitored on a monthly basis spanning the ovulation and egg laying period. During the hatching season microcystin concentrations in unfertilised eggs, egg shell membranes and in the yolk and liver of dead hatchlings were determined using liquid chromatography-high resolution mass spectrometry (LC-HRMS). Microcystins were detected in Nile crocodile egg and hatchling samples. Microcystin (MC-LR, MC-RR, MC-YR) concentrations in the crocodile egg and hatchling samples collected from clutches with a good hatching rate (≥90%) ranged between 0 and 1.76 ng g(-1), with the highest concentration in the egg shell membranes. Microcystin concentrations in samples collected from clutches with a bad hatching rate (≤10%) ranged from 0 - 1.63 ng g(-1) with the highest concentration detected in the hatchling yolk. However, the concentrations were probably underestimated as the percentage recovery from spiked samples was very low with the extraction method employed

  15. Impact of climate change on water and agriculture: Challenges and possible solutions for the Nile Delta

    NASA Astrophysics Data System (ADS)

    Mabrouk, Badr; Arafa, Salah; Farahat, Hany; Badr, Marmar; Gampe, David; Ludwig, Ralf

    2013-04-01

    The Nile-Delta is subjected to continuous changes; including shoreline changes either erosion or accretion, subsidence of the delta, as well as sea level rise due to climate change. The impacts of climate change on the Nile Delta have been addressed on local and international level as the Nile Delta coastal zones are vulnerable to sea level rise. The poster presents recent research activities and findings from the CLIMB project in the Nile Delta and costal zones of Egypt. Lots of field data have been collected such as aquifer geometry data, soil properties data, well data and contamination sources. All of these data support a coupled modeling approach of the land surface hydrological model WASIM-ETH and the hydrological model MOD-Flow to simulate and project the future impact translation of climate projections into hydrological impacts. Results confirm intensified threads to water security. Increasing potential evaporation (in response to increasing temperature) in combination with decreasing water levels in the Nile river, reduced precipitation and groundwater recharge and deteriorating groundwater quality, imposes great challenges to ensure the supply of drinking water and irrigation. Current irrigation strategies are highly inefficient and must be replaced by new and adapted systems. Based on the results of the coupled modeling approach, various scenarios can be evaluated. The vision is to develop a road map for climate change and green economy that maximizes wellbeing of the Egyptian citizens, operates with environmental limits, and is capable of adapting to global environmental change.

  16. Blue Hole, Little Miami River.

    ERIC Educational Resources Information Center

    Thoman, Carol

    1986-01-01

    Students in grades 10-12 are introduced to a romantic-realist approach to landscape painting using masterpiece by Robert S. Duncanson. The activity helps students consider the decisions artists make in choosing how they will interpret nature. (RM)

  17. Blue Hole, Little Miami River.

    ERIC Educational Resources Information Center

    Thoman, Carol

    1986-01-01

    Students in grades 10-12 are introduced to a romantic-realist approach to landscape painting using masterpiece by Robert S. Duncanson. The activity helps students consider the decisions artists make in choosing how they will interpret nature. (RM)

  18. [West Nile fever/encephalitis].

    PubMed

    Takasaki, Tomohiko

    2007-12-01

    West Nile virus (WNV), a member of the family Flaviviridae (genus Flavivirus), is a mosquito-borne virus first isolated in 1937 in the West Nile district of Uganda. The disease in humans is characterized by a dengue-like illness with fever, and a more severe form is characterized by central nervous system involvement, including encephalitis, meningitis, and myelitis. WN encephalitis was first reported in the Western Hemisphere in the summer of 1999, there was an outbreak in New York City. Epidemic WNV strains in North America are severely pathogenic, however, attenuated WNV strains were found in Texas and Mexico in 2003. The principal vectors of WNV transmission in North America are Culex. pipiens, Cx. Quinquefasciatus, Cx. restuans, Cx salinarius and Cx talsalis. The number of WN fever case has exceeded 27,000 since 1999 in the United States and 4,600 since 2002 in Canada. The first imported case of West Nile fever in Japan was confirmed in September, 2005. The patient had returned to Japan from the United States and developed symptoms the next day. There is currently no WN vaccine for use in humans. An inactivated WNV vaccine for use in horses has been available since 2001. A DNA vaccine, a chimeric live attenuated vaccine, and a recombinant vaccine have also been licensed for use in horses.

  19. A distal 145 ka sediment record of Nile discharge and East African monsoon variability

    NASA Astrophysics Data System (ADS)

    Ehrmann, W.; Schmiedl, G.; Seidel, M.; Krüger, S.; Schulz, H.

    2015-09-01

    Clay mineral assemblages in a sediment core from the distal Nile discharge plume off Israel have been used to reconstruct the late Quaternary Nile sediment discharge into the Eastern Mediterranean Sea (EMS). The record spans the last ca. 145 ka. Smectite abundances indicate the influence of the Blue Nile and Atbara that have their headwaters in the volcanic rocks of the Ethiopian highlands. Kaolinite abundances indicate the influence of wadis, which contribute periodically to the suspension load of the Nile. Due to the geographical position, the climate and the sedimentary framework of the EMS is controlled by two climate systems. The long-term climate regime was governed by the African monsoon that caused major humid periods with enhanced sediment discharge at 132 to < 122 ka (AHP 5), 113 to 104 ka (AHP 4), and 86 to 74 ka (AHP 3). They lasted much longer than the formation of the related sapropel layers S5, S4 and S3. During the last glacial period (MIS 4-2) the long-term changes of the monsoonal system were superimposed by millennial-scale changes of an intensified mid-latitude glacial system. This climate regime caused short but pronounced drought periods in the Nile catchment, which are linked to Heinrich Events and alternate with more humid interstadials. The clay mineral record further implies that feedback mechanisms between vegetation cover and sediment discharge of the Nile are detectable but of minor importance for the sedimentary record in the southeastern Mediterranean Sea during the investigated African Humid Periods.

  20. Estimation of crustal movements using the Global Positioning System (GPS) measurements along Nile Valley area, Egypt from 2007 to 2012

    NASA Astrophysics Data System (ADS)

    Sakr, Kamal; Radwan, Ali M.; Rashwan, Mohamed; Gomaa, Mahmoud

    2015-06-01

    The Nile Valley in Egypt is located to the west of the Red Sea Rift and to the south of the Mediterranean Sea. Recently, some moderate earthquakes were occurred along the Nile Valley at the eastern and western side. Tectonically, the Nile Valley is controlled by NW-SE, NE-SW, E-W and N-S tectonic trends due to the exerted forces and stresses. A program of studying the recent crustal movements in Egypt has been started since 1984 to cover some areas which are characterized by the occurrence of felt Earthquakes. One of these areas is the Nile Valley. About 6 moderate earthquakes with magnitudes more than 4 were occurred on both sides of River Nile. The present study aimed to determine the recent crustal movement parameters along the Nile Valley using the Global Positioning System (GPS) measurements. To achieve this mission, a GPS network consisting of ten geodetic stations has been established on both sides along the Nile Valley area. GPS measurements have been collected from 2007 to 2012. The collected data were processed using Bernese 5.0 Software. The result of the data analysis indicates that the rate of local velocity is small ranging from 1 to 4 mm/year. This rate is consistent with the low rate of occurrence of recent earthquakes activity along the Nile Valley area. But, the results obtained from the calculation of the regional velocity indicated that the velocity of the GPS stations including the African Plate motion is about 25 mm/year in the northeast direction which is consistent with the African Plate motion direction.

  1. Blue Laser.

    DTIC Science & Technology

    1985-12-01

    HOLLOW CATHODE LASER FABRICATION 13 4. EXPERIENCE WITH THE BLUE LASER 18 4.1 Operational and Processing Experience 18 4.2 Performance Testing 20 5...34 -. - . •. SECTION 3 BLUE HOLLOW CATHODE LASER FABRICATION This section presents an overview of the steps taken in creating a HCL. There is...to the laser assembly. These steps can actually be considered as the final steps in laser fabrication because some of them involve adding various

  2. Thyroid Hormones, Retinol and Clinical Parameters in Relation to Mercury and Organohalogen Contaminants in Great Blue Heron (Ardea herodias) Nestlings from the St. Lawrence River, Québec, Canada.

    PubMed

    Champoux, Louise; Boily, Monique; Fitzgerald, Guy

    2017-02-01

    The exposure and effects of persistent environmental contaminants were investigated in great blue heron (Ardea herodias) nestlings sampled in 2001, 2002, 2006, and 2007 in freshwater and estuarine heronries along the St. Lawrence River, Québec (Canada). Biomarkers (retinoids, thyroid hormones, and clinical parameters) and contaminants (organochlorine contaminants, polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs), and mercury (Hg)) were analyzed in blood, and Hg was analyzed in feathers (generally 9 nestlings per colony and 4 colonies per year). Feather Hg and most contaminants detected in blood were found in higher concentrations in birds from freshwater than estuarine colonies more distant from the pollution sources. Among freshwater colonies, Ile aux Hérons showed the highest levels of contaminants, with mean Hg concentrations of 8.4 and 0.55 mg/kg in feathers and plasma, respectively, and plasma ΣBFRs of 19.6 ng/g ww. The highest mean ΣPCBs, 56.5 ng/g ww, was measured at Grande Ile in 2001. The levels of contaminants in heron nestlings were generally below critical thresholds for adverse effects observed on reproduction or survival. Retinol, dehydroretinol (DROH), and thyroid hormone concentrations differed significantly among colonies. Retinol concentrations were negatively related to ΣPCBs, whereas DROH concentrations were negatively related to Hg and total and free triiodothyronine (T3) concentrations were negatively related to ΣBFRs. These results indicate that contaminants from the St. Lawrence River could impair the development and fitness of great blue heron nestlings and emphasize the need for more research on the great blue heron population to assess their health and nutritional status.

  3. West Nile virus and "poliomyelitis".

    PubMed

    Sejvar, James J

    2004-07-27

    West Nile virus (WNV) has recently been associated with a syndrome of acute flaccid paralysis. Most cases of WNV-associated weakness have clinical, histopathologic, and electrophysiologic characteristics indistinguishable from those of poliomyelitis caused by infection with poliovirus. There is debate about the nomenclature of this manifestation of WNV infection. An historical perspective of the term "poliomyelitis" suggests that the term "WNV poliomyelitis" seems appropriate, but members of the neurologic and infectious disease communities should engage in discussion regarding the terminology of this syndrome.

  4. West Nile Virus: an overview.

    PubMed

    Hale, Deborah

    2015-05-01

    West Nile Virus is the most frequent cause of arboviral disease in the United States. It was first identified in the United States in 1999. Since that time, each of the 48 contiguous states in the United States has seen the disease, and it has been found in 96% of the U.S. counties in infected humans, mosquitoes, birds, horses, or other mammals. Although most often the disease resolves on its own, patients can develop serious and life-threatening complications, and may need further monitoring and treatment. This article reviews the prevalence, transmission, signs and symptoms, complications, treatment, surveillance, and prevention of the disease.

  5. The rivers of civilization

    NASA Astrophysics Data System (ADS)

    Macklin, Mark G.; Lewin, John

    2015-04-01

    The hydromorphic regimes that underpinned Old World river-based civilizations are reviewed in light of recent research. Notable Holocene climatic changes varied from region to region, whilst the dynamics of floodplain environments were equally diverse, with river channel changes significantly affecting human settlement. There were longer-term trends in Holocene hydroclimate and multi-centennial length 'flood-rich' and 'flood-poor' episodes. These impacted on five identified flooding and settlement scenarios: (i) alluvial fans and aprons; (ii) laterally mobile rivers; (iii) rivers with well-developed levees and flood basins; (iv) river systems characterised by avulsions and floodouts; and (v) large river-fed wetlands. This gave a range of changes that were either more or less regular or incremental from year-to-year (and thus potentially manageable) or catastrophic. The latter might be sudden during a flood event or a few seasons (acute), or over longer periods extending over many decades or even centuries (chronic). The geomorphic and environmental impacts of these events on riparian societies were very often irreversible. Contrasts are made between allogenic and autogenic mechanism for imposing environmental stress on riverine communities and a distinction is made between channel avulsion and contraction responses. Floods, droughts and river channel changes can precondition as well as trigger environmental crises and societal collapse. The Nile system currently offers the best set of independently dated Holocene fluvial and archaeological records, and the contrasted effects of changing hydromorphological regimes on floodwater farming are examined. The persistence of civilizations depended essentially on the societies that maintained them, but they were also understandably resilient in some environments (Pharaonic Egypt in the Egyptian Nile), appear to have had more limited windows of opportunity in others (the Kerma Kingdom in the Nubian Nile), or required

  6. Estimation of Some Bio-Physical Indicators for Sustainable Crop Production in the Eastern Nile Basin of Sudan Using Landsat-8 Imagery and SEBAL Model

    NASA Astrophysics Data System (ADS)

    Guma Biro Turk, Khalid

    2016-07-01

    Crop production under modern irrigation systems require unique management at field level and hence better utilization of agricultural inputs and water resources. This study aims to make use of remote sensing (RS) data and the surface energy balance algorithm for land (SEBAL) to improve the on-farm management. The study area is located in the Eastern part of the Blue Nile River about 60 km south of Khartoum, Sudan. Landsat-8 data were used to estimate a number of bio-physical indicators during the growing season of the year 2014/2015. Accordingly, in-situ weather data and SEBAL model were applied to calculate: the reference (ET0), actual (ETa) and potential (ETp) evapotranspiration, soil moisture (SM), crop factor (kc), nitrogen (N), biomass production (BP) and crop water productivity (CWP). Results revealed that ET0 showed steady variation throughout the year, varying from 5 to 7 mm/day. However, ETa and ETp showed clear temporal variation attributed to frequent cutting of the alfalfa, almost monthly. The BP of the alfalfa was observed to be high when there is no cutting activates were made before the image acquisition date. Nevertheless the CWP trends are following the biomass production ones, low when there is no biomass and high when the biomass is high. The application of SEBAL model within the study area using the Landsat-8 imagery indicates that it's possible to produce field-based bio-physical indicators, which can be useful in monitoring and managing the field during the growing season. However, a cross-calibration with the in-situ data should be considered in order to maintain the spatial variability within the field. Keywords: Bio-physical Indicators; Remote Sensing; SEBAL; Landsat-8; Eastern Nile Basin

  7. West Nile virus and the climate.

    PubMed

    Epstein, P R

    2001-06-01

    West Nile virus is transmitted by urban-dwelling mosquitoes to birds and other animals, with occasional "spillover" to humans. While the means by which West Nile virus was introduced into the Americas in 1999 remain unknown, the climatic conditions that amplify diseases that cycle among urban mosquitoes, birds, and humans are warm winters and spring droughts. This information can be useful in generating early warning systems and mobilizing timely and the most environmentally friendly public health interventions. The extreme weather conditions accompanying long-term climate change may also be contributing to the spread of West Nile virus in the United States and Europe.

  8. West Nile Virus and wildlife

    USGS Publications Warehouse

    Marra, P.P.; Griffing, S.; Caffrey, C.; Kilpatrick, A.M.; McLean, R.; Brand, C.; Saito, E.; Dupuis, A.P.; Kramer, Laura; Novak, R.

    2004-01-01

    West Nile virus (WNV) has spread rapidly across North America, resulting in human deaths and in the deaths of untold numbers of birds, mammals, and reptiles. The virus has reached Central America and the Caribbean and may spread to Hawaii and South America. Although tens of thousands of birds have died, and studies of some bird species show local declines, few regionwide declines can be attributed to WNV. Predicting future impacts of WNV on wildlife, and pinpointing what drives epidemics, will require substantial additional research into host susceptibility, reservoir competency, and linkages between climate, mosquitoes, and disease. Such work will entail a collaborative effort between scientists in governmental research groups, in surveillance and control programs, and in nongovernmental organizations. West Nile virus was not the first, and it will not be the last, exotic disease to be introduced to the New World. Its spread in North America highlights the need to strengthen animal monitoring programs and to integrate them with research on disease ecology.

  9. Diversification of West Nile virus in a subtropical region.

    PubMed

    Chisenhall, Daniel M; Mores, Christopher N

    2009-07-16

    West Nile virus (WNV) has spread across North, Central, and South America since its introduction in 1999. At the start of this spread, Florida was considered a potentially important area with regards to transmission due to its geographic, climatological, and demographic conditions. Curiously, the anticipated high levels of transmission or disease outbreaks have not been observed. As other studies have predicted that the lack of intense WNV transmission is not due to vector incompetence, we sought to evaluate the role of viral strain diversity in WNV transmission in Florida. Therefore, a phylogentic analysis was carried out on several isolates collected from three distinct locations in Florida. Contrasting with a positive control collected in Indian River County, Florida during 2003 that contains the original NY99 genotype with valanine at amino acid 159 of the envelope region, all of the isolates collected in 2005 contain the WN02 genotype composed of a substation with alanine at that position indicating the window of introduction of the WN02 genotype occurred between 2003 and 2005. From the eight isolates collected in Duval, Indian River, and Manatee Counties; there is also a silent nucleotide substitution that differentiates the isolates collected on the Atlantic side of the state compared to the isolate collected on the Gulf side, which groups closer to isolates from other locations near the Gulf. As a whole, the Florida isolates contained numerous variable nucleotide and amino acid sites from the reference sequences, as well as each other; indicating greater nucleotide diversity within the Florida 2005 isolates than within other regions. Finally, a series of three amino acid substitutions surrounding a set of histidines located in the envelope coding region that hypothesized to play a role in conformational changes was found in the isolate collected in Indian River County, perhaps changing the antigenicity of the homodimer. Taken together, these findings expand

  10. Diversification of West Nile virus in a subtropical region

    PubMed Central

    Chisenhall, Daniel M; Mores, Christopher N

    2009-01-01

    Background West Nile virus (WNV) has spread across North, Central, and South America since its introduction in 1999. At the start of this spread, Florida was considered a potentially important area with regards to transmission due to its geographic, climatological, and demographic conditions. Curiously, the anticipated high levels of transmission or disease outbreaks have not been observed. As other studies have predicted that the lack of intense WNV transmission is not due to vector incompetence, we sought to evaluate the role of viral strain diversity in WNV transmission in Florida. Therefore, a phylogentic analysis was carried out on several isolates collected from three distinct locations in Florida. Results Contrasting with a positive control collected in Indian River County, Florida during 2003 that contains the original NY99 genotype with valanine at amino acid 159 of the envelope region, all of the isolates collected in 2005 contain the WN02 genotype composed of a substation with alanine at that position indicating the window of introduction of the WN02 genotype occurred between 2003 and 2005. From the eight isolates collected in Duval, Indian River, and Manatee Counties; there is also a silent nucleotide substitution that differentiates the isolates collected on the Atlantic side of the state compared to the isolate collected on the Gulf side, which groups closer to isolates from other locations near the Gulf. Conclusion As a whole, the Florida isolates contained numerous variable nucleotide and amino acid sites from the reference sequences, as well as each other; indicating greater nucleotide diversity within the Florida 2005 isolates than within other regions. Finally, a series of three amino acid substitutions surrounding a set of histidines located in the envelope coding region that hypothesized to play a role in conformational changes was found in the isolate collected in Indian River County, perhaps changing the antigenicity of the homodimer. Taken

  11. Genetic differentiation among natural populations of the Nile tilapia Oreochromis niloticus (Teleostei, cichlidae).

    PubMed

    Agnèse, J F; Adépo-Gourène, B; Abban, E K; Fermon, Y

    1997-07-01

    We analysed the genetic differentiation among 17 natural populations of the Nile tilapia Oreochromis niloticus (Linnaeus, 1758) using allozymes and restriction fragment length polymorphism (RFLP) of mitochondrial DNA (mtDNA). The populations studied, from the River Senegal to Lake Tana and from Lake Manzalla to Lake Baringo, represent all subspecies which have been previously described. Sixteen variable nuclear loci showed that these populations can be clustered in three groups: (1) West African populations (Senegal, Niger, Volta and Chad drainages), (2) Ethiopian Rift Valley populations (Lakes Awasa, Ziway, Koka and the Awash River) and (3) Nile drainage (Manzalla, Cairo, Lake Edward) and Kenyan Rift Valley populations (Lakes Turkana, Baringo and River Suguta). Nine different mtDNA haplotypes were found in the RFLP analysis of a 1 kb portion of the D-loop region. The network obtained showed that there are three geographically distinct groups; all West African populations and O. aureus are clustered, the two Ethiopian Rift Valley populations are distinct and between these two groups are the Kenyan and Ugandan Rift Valley populations. Nile populations show affinities both with West African populations and with specimens from Lakes Tana and Turkana. Taxonomic and biogeographical implications of these results are discussed.

  12. Geology and ground water in the Platte-Republican Rivers watershed and the Little Blue River basin above Angus, Nebraska, with a section on chemical quality of the ground water

    USGS Publications Warehouse

    Johnson, C.R.; Brennan, Robert

    1960-01-01

    saturation because the ground water, as it percolates southeastward beneath the area, moves out of the Tertiary and into the Quaternary deposits without apparent hindrance. The water that enters the area as underflow from the west is augmented within the area by water that infiltrates from the land surface. The principal sources of irrigating water are precipitation, seepage from canals and reservoirs, and applied irrigation water. Except for the water withdrawn through wells or discharged by natural processes where valleys have been cut into the zone of saturation, ground water leaves the area as underflow into the Platte River valley on the north, the Blue River drainage basin on the east, or the Republican River valley on the south. Part of the water used for irrigation and watering livestock and all the water used in rural and urban homes, in public buildings, and for industrial purposes is obtained from wells, To date (1952) there is no indication that the supply of ground water is being depleted faster than it is being replenished; instead, studies indicate that greater quantities can be withdrawn without causing an excessive decline of the water table. An increase of ground-water withdrawals to a sustainable maximum, however, will be possible only if the points of withdrawal are scattered fairly uniformly. It is estimated that annual withdrawals per township should not exceed 2,100 acre-feet where infiltrating precipitation is the only source of recharge, or 3,000 acre-feet where other sources of recharge are significant. Although perennial withdrawals of this amount could be sustained indefinitely, they would cause some lowering of the water table and eventually a decrease in the amount of water discharged from the area by natural means. The ground water is of the calcium bicarbonate type. In much of the area it is hard or very hard, and in places it contains excessive amounts of iron. In all other respects the water is chemically suitable for domesti

  13. Blue gods, blue oil, and blue people.

    PubMed

    Fairbanks, V F

    1994-09-01

    Studies of the composition of coal tar, which began in Prussia in 1834, profoundly affected the economies of Germany, Great Britain, India, and the rest of the world, as well as medicine and surgery. Such effects include the collapse of the profits of the British indigo monopoly, the growth in economic power of Germany based on coal tar chemistry, and an economic crisis in India that led to more humane tax laws and, ultimately, the independence of India and the end of the British Empire. Additional consequences were the development of antiseptic surgery and the synthesis of a wide variety of useful drugs that have eradicated infections and alleviated pain. Many of these drugs, particularly the commonly used analgesics, sulfonamides, sulfones, and local anesthetics, are derivatives of aniline, originally called "blue oil" or "kyanol." Some of these aniline derivatives, however, have also caused aplastic anemia, agranulocytosis, and methemoglobinemia (that is, "blue people"). Exposure to aniline drugs, particularly when two or three aniline drugs are taken concurrently, seems to be the commonest cause of methemoglobinemia today.

  14. Drought May Beckon Bigger West Nile Outbreaks

    MedlinePlus

    ... affect transmission of the virus between mosquitoes and birds by stressing birds or changing where they gather. Mosquitoes become infected ... West Nile virus when they feed on infected birds, according to the U.S. Centers for Disease Control ...

  15. A regional approach to climate adaptation in the Nile Basin

    NASA Astrophysics Data System (ADS)

    Butts, Michael B.; Buontempo, Carlo; Lørup, Jens K.; Williams, Karina; Mathison, Camilla; Jessen, Oluf Z.; Riegels, Niels D.; Glennie, Paul; McSweeney, Carol; Wilson, Mark; Jones, Richard; Seid, Abdulkarim H.

    2016-10-01

    The Nile Basin is one of the most important shared basins in Africa. Managing and developing the water resources within the basin must not only address different water uses but also the trade-off between developments upstream and water use downstream, often between different countries. Furthermore, decision-makers in the region need to evaluate and implement climate adaptation measures. Previous work has shown that the Nile flows can be highly sensitive to climate change and that there is considerable uncertainty in climate projections in the region with no clear consensus as to the direction of change. Modelling current and future changes in river runoff must address a number of challenges; including the large size of the basin, the relative scarcity of data, and the corresponding dramatic variety of climatic conditions and diversity in hydrological characteristics. In this paper, we present a methodology, to support climate adaptation on a regional scale, for assessing climate change impacts and adaptation potential for floods, droughts and water scarcity within the basin.

  16. Trichinella zimbabwensis in wild Nile crocodiles (Crocodylus niloticus) of South Africa.

    PubMed

    La Grange, Louis J; Marucci, Gianluca; Pozio, Edoardo

    2009-04-06

    Recent discovery of Trichinella zimbabwensis in crocodiles from Zimbabwe, Lake Cahora Basa, Mozambique, and from lake Abaja, Ethiopia, prompted strict control measures to curb the possible spread of the infection to humans and also to prevent its introduction to other countries, which were considered free of this pathogen. In 2006, the Chief Directorate Veterinary Services of Mpumalanga Province of South Africa launched a survey to investigate the status of wild and commercial breeding crocodiles in the province. To evaluate if T. zimbabwensis was circulating in the environments where crocodiles are living in South Africa, 9 fish, 36 reptiles (including 27 Nile crocodiles) and 4 mammals have been investigated to detect Trichinella sp. larvae in their muscles. In January 2008, a Nile crocodile from Komatipoort, sampled by means of a tail biopsy, tested positive for Trichinella larvae. In June-July 2008, Trichinella sp. larvae were also detected in four other Nile crocodiles from the Olifants River Gorge. The prevalence of Trichinella infection in the investigated wild Nile crocodiles from South Africa is 38.5%. The larvae were identified as belonging to T. zimbabwensis by multiplex-PCR. These are the first reports of T. zimbabwensis in South Africa and suggest that the distribution area of this parasite species is wider than that believed in the past.

  17. West Nile virus: North American experience

    USGS Publications Warehouse

    Hofmeister, Erik K.

    2011-01-01

    West Nile virus, a mosquito-vectored flavivirus of the Japanese encephalitis serogroup, was first detected in North America following an epizootic in the New York City area in 1999. In the intervening 11 years since the arrival of the virus in North America, it has crossed the contiguous USA, entered the Canadian provinces bordering the USA, and has been reported in the Caribbean islands, Mexico, Central America and, more recently, South America. West Nile virus has been reported in over 300 species of birds in the USA and has caused the deaths of thousands of birds, local population declines of some avian species, the clinical illness and deaths of thousands of domestic horses, and the clinical disease in over 30 000 Americans and the deaths of over 1000. Prior to the emergence of West Nile virus in North America, St. Louis encephalitis virus and Dengue virus were the only other known mosquito-transmitted flaviviruses in North America capable of causing human disease. This review will discuss the North American experience with mosquito-borne flavivirus prior to the arrival of West Nile virus, the entry and spread of West Nile virus in North America, effects on wild bird populations, genetic changes in the virus, and the current state of West Nile virus transmission.

  18. West Nile Virus in California

    PubMed Central

    Lothrop, Hugh; Chiles, Robert; Madon, Minoo; Cossen, Cynthia; Woods, Leslie; Husted, Stan; Kramer, Vicki; Edman, John

    2004-01-01

    West Nile virus (WNV) was first isolated in California during July 2003 from a pool of Culex tarsalis collected near El Centro, Imperial County. WNV transmission then increased and spread in Imperial and Coachella Valleys, where it was tracked by isolation from pools of Cx. tarsalis, seroconversions in sentinel chickens, and seroprevalence in free-ranging birds. WNV then dispersed to the city of Riverside, Riverside County, and to the Whittier Dam area of Los Angeles County, where it was detected in dead birds and pools of Cx. pipiens quinquefasciatus. By October, WNV was detected in dead birds collected from riparian corridors in Los Angeles, west to Long Beach, and through inland valleys south from Riverside to San Diego County. WNV was reported concurrently from Arizona in mid-August and from Baja, Mexico, in mid-November. Possible mechanisms for virus introduction, amplification, and dispersal are discussed. PMID:15496236

  19. Measurements of Land Subsidence Rates on the North-western Portion of the Nile Delta Using Radar Interferometry Techniques

    NASA Astrophysics Data System (ADS)

    Fugate, Joseph M.

    The Nile Delta is home to around 75 million people and most of Egypt's farmland and agricultural production. This area is currently threatened by Mediterranean Sea waters due to factors such as sediment starvation, climate change, and sea level fluctuations as well as subsidence. The low elevation and relief of the Nile Delta exposes many coastal communities, including the city of Alexandria, to potential inundation. This situation has become a concern for the area's residents but a better understanding of the processes occurring there can aid in deciding a suitable response. Recent studies have documented Holocene subsidence rates in the northeast part of the Nile Delta that average up to 8mm/year. In this study, PS-InSAR techniques are used to measure modern land subsidence rates on the north-central and north-western Nile Delta. Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) techniques were applied to 23 ESA radar scenes from 2 orbital tracks spanning from 1992 to 2000 in the north-central and north-west portions of the Nile Delta. The area includes the cities of Alexandria, Greater Mahala, and Mansoura as well as the Rosetta promontory and lake Burullus, Idku Lagoon, and Maryut Lagoon. Results indicate that modern average-vertical ground motion velocities for the north-western and north-central Nile Delta range from emergent to subsidence of 8.5 mm/yr. The range of velocities measured are spatially varied in a complex way across the study area. Patterns of subsidence correlate closely to areas of most recent sediment deposition such as along coastlines and rivers, as well as in lagoons and lakes. Average subsidence velocities are also lower across the western sections of the Nile Delta than in the northeastern delta.

  20. Temporal trends of mercury and organohalogen contaminants in great blue heron eggs from the St. Lawrence River, Québec, Canada, 1991-2011, and relationships with tracers of feeding ecology.

    PubMed

    Champoux, Louise; Boily, Monique

    2017-12-31

    Since 1991, great blue heron (Ardea herodias) eggs have been collected and analyzed for mercury (Hg), persistent organic contaminants (OCs), brominated and non-brominated flame retardants (FRs) as well as stable isotopes δ(13)C and δ(15)N. In the present study, temporal trends of contaminants were analyzed in eggs sampled in four regions along the St. Lawrence River (Quebec, Canada) and inland sites using new and previously published data. Most contaminants declined significantly over time in most regions. Globally, the highest annual change, -17.5%, was found for pp'-DDD, while the smallest annual decline, -0.54%, was observed for Hg. Concentrations of ΣDDT and ΣFR8 (sum of 8 congeners) decreased by -11.6% and -7.3%, respectively. Declines in ΣPCBs differed among regions, from -5.6% in the fluvial section to -14.7% in the inland region. The highest concentration of ΣFR8 was measured in eggs from Grande Ile in the fluvial section of the river in 1996 (2.39μg/g). Stable isotope ratios also showed temporal trends in some regions: δ(13)C decreased in the fluvial section and increased in Gulf region, while δ(15)N decreased in the fluvial section and increased in the upper estuary. Significant positive relationships were found between ΣDDT, ΣPCBs and ΣFRs and δ(15)N and δ(13)C in freshwater colonies, but not in estuarine or marine colonies. These results suggest that changes in trophic level and foraging areas over time were influential factors with respect to contaminant burden in great blue heron eggs in the fluvial section, but not in the other regions. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  1. Modeling of Groundwater Quantity and Quality Management, Nile Valley, Egypt

    NASA Astrophysics Data System (ADS)

    Owlia, R.; Fogg, G. E.

    2012-12-01

    Groundwater levels have been rising in the Luxor area of Egypt due to increased agricultural irrigation following the construction of the Aswan High Dam (AHD) in 1970. This has led to soil and groundwater salinity problems caused by increasing evapotranspiration from shallower water table, as well as the degradation of historical monuments whose foundations are weakening by capillary rise of water into the columns and stonework. While similar salinity problems exist elsewhere in the world (e.g., San Joaquin Valley of California), we hypothesize that as long as groundwater discharge to the Nile River continues and serves as a sink for the salt, the regional salt balance will be manageable and will not lead to irreversible salinization of soils. Further, we hypothesize that if a groundwater system such as this one becomes overdrafted, thereby cutting off groundwater discharge to the River, the system salt balance will be less manageable and possibly non-sustainable. With groundwater flow modeling we are investigating approaches for managing the irrigation and groundwater levels so as to eliminate water stresses on Egyptian monuments and antiquities. Consequences of possible actions for managing the water table through groundwater pumping and alternative irrigation practices will be presented. Moreover, through the use of high resolution modeling of system heterogeneity, we will simulate the long term salt balance of the system under various scenarios, including the overdraft case. The salt source will be a function of groundwater discharge to the surface via bare-soil evaporation and crop transpiration. The built-in heterogeneity will account for dispersion, fast transport in connected media and slow mass transfer between aquifer and aquitard materials. Key Words: Groundwater, modeling, water quality, sustainability, salinity, irrigated agriculture, Nile aquifer.

  2. Sinuolinea niloticus n. sp., a myxozoan parasite that causes disease in Nile tilapia (Oreochromis niloticus).

    PubMed

    Vaz Rodrigues, Marianna; Francisco, Claire Juliana; Biondi, Germano Francisco; Júnior, João Pessoa Araújo

    2016-11-01

    Sinuolinea species are myxozoans of the order Bivalvulida, suborder Variisporina, and family Sinuolineidae, which can be parasites for freshwater and marine fish. The aim of this study was to describe the occurrence of Sinuolinea niloticus n. sp. infecting Nile tilapia (Oreochromis niloticus) from aquaculture and from river sources with morphological and molecular analyses. Between March 2010 and November 2012, 116 Nile tilapia were randomly sampled from aquaculture net fishing (n = 56) in Mira Estrela, São Paulo, and from the Capivari River (n = 60) in Botucatu, São Paulo. The fishes that were sampled were examined by necropsy, microscopic observation and molecular techniques for detection and identification of the myxozoan causing disease in tilapia. All of the tissues that were sampled for analysis showed the presence of the parasite. It was observed by microscopy that the myxozoan belongs to the Sinuolinea genus. This identification was performed based on morphological characteristics and histopathology findings, such as structures consistent with myxozoan in the interstices in all analysed tissues, coagulative necrosis, haemorrhage, inflammatory processes, presence of melano-macrophages and eosinophils. The results of the molecular analyses revealed that the myxozoan detected and identified in this study is sister to a group of other Sinuolinea species. Because this is the first report of this parasite in Nile tilapia, the parasite was named S. niloticus n. sp. This is the first report of a Sinuolinea species in Brazil and in tilapia.

  3. From source to sink: Exploring the Quaternary history of the Nile

    NASA Astrophysics Data System (ADS)

    Woodward, J. C.; Williams, M. A. J.; Garzanti, E.; Macklin, M. G.; Marriner, N.

    2015-12-01

    Nearly two thousand five hundred years have elapsed since the Greek historian Herodotus (ca. 485-425 BC) posed a number of fundamental questions about the source, age, and flood regime of the River Nile. Herodotus travelled widely in Egypt in around 450 BC - mainly in the Delta and Lower Egypt, but he may have journeyed as far upstream as Aswan and the First Cataract. A keen observer of nature, with a questioning intellect, Herodotus very quickly discerned that the dark alluvial soils of Egypt were very different from the desert soils of Syria and Libya, and inferred that they were derived from the Ethiopian headwaters of the Nile. Herodotus was the first to recognize that Egyptian civilization was, as he put it, ;the gift of the river; (Griffiths, 1966) since he understood that, without the regular and reliable hundred days of flooding during the summer months, and the annual deposition of silts along the floodplains, agriculture would not have been possible on any significant scale under the desert climate of the Nile Valley.

  4. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

  5. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

  6. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

  7. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

  8. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false West Nile virus serological reagents. 866.3940... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3940 West Nile virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that...

  9. Holocene palaeo-environments on the western coast of the Nile Delta: local and basin-wide forcing factors

    NASA Astrophysics Data System (ADS)

    Flaux, Clément; Véron, Alain; Marriner, Nick; el-Assal, Mena; Claude, Christelle; Morhange, Christophe

    2014-05-01

    The Canopic branch, which is today either silted up and cultivated or re-used in the modern drainage network, was the main channel for the western Nile Delta during Antiquity. Ancient Canopic flow used to supply the water network on the deltaic margin, including secondary tributaries, the Maryut lake, and irrigation agriculture and urban needs. We present new data obtained from a sediment core taken close to the palaeo-Canopic channel. Lead (Pb) isotopic analyses of bulk sediments, together with sedimentology, macro- and micro-fauna assemblages, magnetic susceptibility and radiocarbon dates provide evidence for environmental changes at the Canopic mouth in addition to changes in Nile sediment sources during the last 6000 years. Alternation of estuarine to lagoonal and peaty biofacies have recorded stages of transgression and progradation. 206Pb/207Pb analyses suggest a change in dominant sediment load from the White Nile to Blue Nile between 6000 and 5000 years cal. BP. The dataset is then compared and contrasted with previous studies, including: (1) a dense grid of dated bio-sedimentological cores data from the northwestern Nile Delta; (2) strontium isotope records of water and sediment fluxes on the delta; and (3) geochemical records from offshore sediment cores. Our analysis attempts to date and discriminate between basin-wide and regional to local forcing agents driving environmental changes at the mouth of the Canopic. The three main factors discussed will include climatic forcing of Nile flow and load changes, relative sea-level variations, and human impacts on the Canopic flow.

  10. ITCZ and ENSO-like pacing of Nile delta hydro-geomorphology during the Holocene

    NASA Astrophysics Data System (ADS)

    Marriner, Nick; Flaux, Clément; Kaniewski, David; Morhange, Christophe; Leduc, Guillaume; Moron, Vincent; Chen, Zhongyuan; Gasse, Françoise; Empereur, Jean-Yves; Stanley, Jean-Daniel

    2012-06-01

    The Nile valley accommodates the world's longest river and shaped the development of numerous complex societies, providing a reliable source of water for farming and linking populations to sub-Saharan Africa and the Mediterranean Sea. Its fertile delta lay at the heart of ancient Egyptian civilization, however little is known of its morpho-sedimentary response to basin-wide changes in Holocene hydrology. Here, we present two well-resolved records from the Nile delta (based on ˜320 radiocarbon dates) to reconstruct the timing and rhythm of catchment-scale modifications during the past 8000 years. On the orbital timescale, we demonstrate that Nilotic hydrology and sedimentation have responded to low-latitude insolation forcing while, on sub-millennial timescales, many of the major phases of deltaic modification were mediated by climate events linked to El Niño Southern Oscillation-type (ENSO) variability.

  11. The Nile floodplain, hydroclimatic variability, and its relation with cultural dynamics in ancient Thebes (Luxor, Egypt)

    NASA Astrophysics Data System (ADS)

    Toonen, Willem H. J.; Graham, Angus; Pennington, Ben; Hunter, Morag; Strutt, Kris; Barker, Dominic; Masson, Aurelia; Emery, Virginia

    2016-04-01

    The western bank of the river Nile in the Luxor region (Egypt) separates New Kingdom divine temple complexes in the central axis of the river valley from contemporaneous sites on the desert edge and limestone plateau. The intermediate Nile floodplain features relatively few known archaeological sites, but played an important role in the ancient ritual landscape by connecting the focal region of the living (floodplain) with that of the dead (desert). All Royal Funerary Temple Complexes of the New Kingdom period (1539-1077 BCE), which played a central role in the cosmogonical landscape, are positioned within a confined 3.5 km long strip of land on the western edge of the present floodplain. This preferential location, together with contemporary textual sources and tomb scenes suggesting the nearby presence of canals, have led to the hypothesis that natural and human-made waterways may have once connected the main channel of the Nile with the desert edge. Until the present research took place, no detailed study of pre-existing channel networks existed in the region, leaving a gap in current knowledge on the configuration and use of the ancient floodplain. This study presents the results of a multi-disciplinary study aimed at mapping and dating ancient waterways in the Theban region and aims to find evidence for the natural or human origin of such channels. Boreholes and Electric Resistivity Tomography (ERT) were carried out along a transect that connects the edge of the Holocene floodplain with the current position of the river Nile. Satellite imagery and textual sources were also used to augment the fieldwork. The data indicate the presence of an infilled abandoned channel of the Nile in the western distal part of the current floodplain, adjoining the Funerary Temple complexes. Over 2100 ceramic fragments were analysed from the sedimentary infilling of the silted-up river course, dating it to the end of the New Kingdom, and indicating that the channel and temples

  12. Blue Saturn

    NASA Image and Video Library

    2004-03-19

    Bands and spots in Saturn's atmosphere, including a dark band south of the equator with a scalloped border, are visible in this image from the Cassini-Huygens spacecraft. The narrow angle camera took the image in blue light on Feb. 29, 2004. The distance to Saturn was 59.9 million kilometers (37.2 million miles). The image scale is 359 kilometers (223 miles) per pixel. Three of Saturn's moons are seen in the image: Enceladus (499 kilometers, or 310 miles across) at left; Mimas (398 kilometers, or 247 miles across) left of Saturn's south pole; and Rhea (1,528 kilometers, or 949 miles across) at lower right. The imaging team enhanced the brightness of the moons to aid visibility. The BL1 broadband spectral filter (centered at 451 nanometers) allows Cassini to "see" light in a part of the spectrum visible as the color blue to human eyes. Scientist can combine images made with this filter with those taken with red and green filters to create full-color composites. Scientists can also assess cloud heights by combining images from the blue filter with images taken in other spectral regions. For example, the bright clouds that form the equatorial zone are the highest in altitude and have pressures at their tops of about one quarter of Earth's atmospheric pressure at sea level. The cloud tops at middle latitudes are lower in altitude and have higher pressures of about half that found at sea level. Analysis of Saturn images like this one will be extremely useful to researchers assessing cloud altitudes during the Cassini-Huygens mission. http://photojournal.jpl.nasa.gov/catalog/PIA05383

  13. Review of West Nile virus epidemiology in Italy and report of a case of West Nile virus encephalitis.

    PubMed

    Delbue, Serena; Ferrante, Pasquale; Mariotto, Sara; Zanusso, Gianluigi; Pavone, Antonino; Chinaglia, Mauro; L'Erario, Roberto; Monaco, Salvatore; Ferrari, Sergio

    2014-10-01

    West Nile virus (WNV) is a flavivirus that causes neurological disorders in less than 1 % of infected subjects. Human cases of WNV-associated fever and/or neurological disorders have been reported in Italy since 2008. The first outbreak occurred in the northeastern region of Italy surrounding the Po River and was caused by the Po River lineage 1 strain, and since then, WNV infections have been reported in several regions of central Italy. Although the virus is highly genetically conserved, stochastic mutations in its genome may lead to the emergence of new strains, as was observed in Italy in 2011 with the identification of two new lineage 1 strains, the WNV Piave and WNV Livenza strains. To help further define WNV epidemiology in Italy, we describe a case of an Italian man living in the Po River area who developed fatal encephalitis in 2009 due to infection with the WNV Piave strain. This finding supports the notion that the Piave strain has been circulating in this area of Italy for 2 years longer than was previously believed.

  14. Late Quaternary floods and droughts in the Nile valley, Sudan: new evidence from optically stimulated luminescence and AMS radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Williams, M. A. J.; Williams, F. M.; Duller, G. A. T.; Munro, R. N.; El Tom, O. A. M.; Barrows, T. T.; Macklin, M.; Woodward, J.; Talbot, M. R.; Haberlah, D.; Fluin, J.

    2010-05-01

    Our results show that the late Pleistocene Nile in northern Sudan was shifting position and actively aggrading at 145 ± 20 kyr, 83 ± 24 kyr, 32 ± 8 kyr and 20.7 ± 0.2 kyr and indicate, for the first time, a phase of high-energy flow in the White Nile at 27.8 ± 3.2 kyr, with still high but somewhat reduced flow in that river at 13.3 kyr, 10 kyr and 4.8-4.0 kyr. Beach ridges associated with a 386 m strandline of the White Nile have OSL ages of 27.5 ± 2.7 kyr and 14.5 ± 1.6 kyr. The Holocene terraces and former channels of the main Nile have ages of 11 kyr, 6.5-5.0 kyr and 4.8-4.0 kyr, after which there was a general decline in flood discharge. The now arid main Nile valley in northern Sudan was significantly wetter during the early to middle Holocene, with a lake up to 450 km 2 in area, fed by an overflow channel from the early Holocene Nile between 9.5 kyr and 7.5 kyr. Previously stable late Pleistocene dunes were reactivated at intervals during the Holocene, with five samples from the White Nile valley indicating brief phases of Holocene dune activity at 9.9 ± 2.0 kyr, 9.0 ± 2.8 kyr, 6.6 ± 0.9 kyr, 4.8 ± 0.9 kyr and 2.9 ± 0.5 kyr, the earliest of which occurred within periods of generally wetter climate and higher Nile flow. The youngest freshwater shells on the Khor Abu Habl alluvial fan west of the White Nile correspond to a time of regionally wetter climate between 1.7 and 1.0 kyr. Our results suggest that millennial scale climatic instability may have been characteristic of Holocene climates in this region.

  15. Impacts of West Nile Virus on wildlife

    USGS Publications Warehouse

    Saito, E.K.; Wild, M.A.

    2004-01-01

    The recent epidemic of West Nile virus in the United States proved to be unexpectedly active and was the largest epidemic of the virus ever recorded. Much remains to be discovered about the ecology and epidemiology of West Nile virus in the United States, including which species are important in maintaining the virus in nature, why some species are more susceptible to lethal infection, and what environmental factors are important in predicting future epidemics. These factors will likely vary regionally, depending on local ecological characteristics. Until scientists better understand the virus and factors influencing its activity, predicting its effects for future seasons is impossible. However, experts are certain about one thing: West Nile virus is here to stay.

  16. Complete Genome Sequence of Streptococcus iniae UEL-Si1, Isolated in Diseased Nile Tilapia (Oreochromis niloticus) from Northern Paraná, Southern Brazil

    PubMed Central

    Gonçalves, Kátia B.; Scarpassa, Josiane A.; Pretto-Giordano, Lucienne G.

    2017-01-01

    ABSTRACT The Streptococcus iniae UEL-Si1 strain was isolated from diseased Nile tilapia within the Paranapanema River Basin, Northern Paraná, Brazil. This is an emerging infectious disease agent of fish from Brazil, and sequencing of the complete genome is fundamental to understanding aspects relative to pathogenesis, infection, epidemiology, and immunity. PMID:28082497

  17. West Nile Virus: Review of the Literature

    PubMed Central

    Petersen, Lyle R.; Brault, Aaron C.; Nasci, Roger S.

    2015-01-01

    IMPORTANCE Since its introduction in North America in 1999,West Nile virus has produced the 3 largest arboviral neuroinvasive disease outbreaks ever recorded in the United States. OBJECTIVE To review the ecology, virology, epidemiology, clinical characteristics, diagnosis, prevention, and control of West Nile virus, with an emphasis on North America. EVIDENCE REVIEW PubMed electronic database was searched through February 5, 2013. United States national surveillance data were gathered from the Centers for Disease Control and Prevention. FINDINGS West Nile virus is now endemic throughout the contiguous United States, with 16 196 human neuroinvasive disease cases and 1549 deaths reported since 1999. More than 780 000 illnesses have likely occurred. To date, incidence is highest in the Midwest from mid-July to early September. West Nile fever develops in approximately 25% of those infected, varies greatly in clinical severity, and symptoms may be prolonged. Neuroinvasive disease (meningitis, encephalitis, acute flaccid paralysis) develops in less than 1% but carries a fatality rate of approximately 10%. Encephalitis has a highly variable clinical course but often is associated with considerable long-term morbidity. Approximately two-thirds of those with paralysis remain with significant weakness in affected limbs. Diagnosis usually rests on detection of IgM antibody in serum or cerebrospinal fluid. Treatment is supportive; no licensed human vaccine exists. Prevention uses an integrated pest management approach, which focuses on surveillance, elimination of mosquito breeding sites, and larval and adult mosquito management using pesticides to keep mosquito populations low. During outbreaks or impending outbreaks, emphasis shifts to aggressive adult mosquito control to reduce the abundance of infected, biting mosquitoes. Pesticide exposure and adverse human health events following adult mosquito control operations for West Nile virus appear negligible. CONCLUSIONS AND

  18. Habitat use and population characteristics of potentially spawning shovelnose sturgeon Scaphirhynchus platorynchus (Rafinesque, 1820), blue sucker ( Cycleptus elongatus (Lesueur, 1817), and associated species in the lower Wisconsin River, USA

    SciTech Connect

    Lyons, John D.; Walchak, D.; Haglund, J.; Kanehl, P.; Pracheil, B.

    2016-11-07

    The goal of this study was to compare the possible locations, timing, and characteristics of potentially spawning shovelnose sturgeon (Scaphirhynchus platorynchus), blue sucker (Cycleptus elongatus), and associated species during the spring of 2007-2015 in the 149-km-long lower Wisconsin River, Wisconsin, USA, a large, shallow, sand-dominated Mississippi River tributary. A 5-km index station of two pairs of rocky shoals surrounded by sandy areas was electrofished for shovelnose sturgeon and blue sucker in a standardized fashion a total of 40 times from late March through mid- June, the presumed spawning period. On one date in 2008 and two dates in 2012, all rocky shoals and adjacent sandy areas in the lowermost 149 km of the river were also electrofished for both species. Shovelnose sturgeon and blue sucker appeared to spawn in the limited rocky areas of the river along with at least four other species: mooneye (Hiodon tergisus), quillback (Carpiodes cyprinus), smallmouth buffalo (Ictiobus bubalus), and shorthead redhorse (Moxostoma macrolepidotum), usually at depths of 0.8-2.0 m and surface velocities of 0.4–1.0 m/s. However, apparently spawning shovelnose sturgeon were found only on mid-channel cobble and coarse gravel shoals within a single 7-km segment that included the 5-km index station, whereas apparently spawning blue suckers were encountered on these same shoals but also more widely throughout the river on eroding bluff shorelines of bedrock and boulder and on artificial boulder wing dams and shoreline rip-rap. Both species showed evidence of homing to the same mid-channel shoal complexes across years.

  19. Does damming of the Colorado River affect the nursery area of blue shrimp Litopenaeus stylirostris (Decapoda: Penaeidae) in the Upper Gulf of California?

    PubMed

    Aragón-Noriega, E A; Calderón-Aguilera, L E

    2000-12-01

    After damming the Colorado River the freshwater flow was reduced to 1% of its virgin flow to the Upper Gulf of California (UGC). The ecological effects need to be properly documented. The UGC is the nursery area for Litopenaeus stylirostris, the most profitable fishery in the zone. In order to know the relative abundance of L. stylirostris postlarval stage we conducted a sampled survey every 14 days in 1993, 1994 and 1997, plus an intensive sampling during a complete tide cycle in July 1995 and 1996. We did 10 min trawls each hour during the flood tide. Relative abundance of postlarvae was higher (p < 0.05) in those years when freshwater flow reached the UGC.

  20. The Blue Bottle Revisited.

    ERIC Educational Resources Information Center

    Vandaveer, Walter R., IV; Mosher, Mel

    1997-01-01

    Presents a modification of the classic Blue Bottle demonstration that involves the alkaline glucose reduction of methylene blue. Uses other indicators in the classic Blue Bottle to produce a rainbow of colors. (JRH)

  1. The Blue Bottle Revisited.

    ERIC Educational Resources Information Center

    Vandaveer, Walter R., IV; Mosher, Mel

    1997-01-01

    Presents a modification of the classic Blue Bottle demonstration that involves the alkaline glucose reduction of methylene blue. Uses other indicators in the classic Blue Bottle to produce a rainbow of colors. (JRH)

  2. Evaluation of West Nile Virus Education Campaign

    PubMed Central

    Neuberger, John S.; Hansen, Gail; Fox, Michael H.

    2005-01-01

    We evaluated the 2003 Kansas West Nile virus public education campaign. Awareness was widespread but compliance was low. Spanish-speaking persons were poorly informed. Relevant factors included population segment variability, campaign content, media choice, and materials delivery methods. PMID:16318730

  3. Nile perch: the great lake experiment.

    PubMed

    Ogutu-ohwayo, R

    1998-01-01

    In order to improve the fishery of Lake Victoria, a large predatory fish, the Nile perch (Lates niloticus), was introduced into the lake to feed on the smaller but abundant haplochromines, thereby producing a larger fish for food consumption. Originally the lake had a very high fish species diversity, dominated by more than 300 species of haplochromine cichlids; however, they were too small to be exploited for food. It took about 20 years for the population of the Nile perch in the lake to increase significantly. Although increased fish production has benefited riparian communities by providing revenue, employment, and food, the introduction of the Nile perch has also resulted in extinction and has transformed the lake ecosystem. In response to the concern caused by the introduction of the Nile perch, the deteriorating water quality, and the need to sustain the lucrative fishery, the governments of Uganda, Kenya, and Tanzania have initiated the multisectoral Lake Victoria Environment Management Programme. Its goals are to control the loading of nutrients and contaminants into the lake, manage land use in the catchment area, manage the introduced fish species, conserve biodiversity, and control the spread of water hyacinths.

  4. Does The Nile Reflect Solar Variability?

    NASA Technical Reports Server (NTRS)

    Ruzmaikin, Alexander; Feynman, Joan; Yung, Yuk

    2006-01-01

    Historical records of the Nile water level provide a unique opportunity to investigate the possibility that solar variability influences the Earth's climate. Particularly important are the annual records of the water level, which are uninterrupted for the years 622-1470 A.D. These records are non-stationary, so that standard spectral analyses cannot adequately characterize them. Here the Empirical Mode Decomposition technique, which is designed to deal with nonstationary, nonlinear time series, becomes useful. It allows the identification of two characteristic time scales in the water level data that can be linked to solar variability: the 88 year period and a time scale of about 200 years. These time scales are also present in the concurrent aurora data. Auroras are driven by coronal mass ejections and the rate of auroras is an excellent proxy for solar variability. Analysis of auroral data contemporaneous with the Nile data shows peaks at 88 years and about 200 years. This suggests a physical link between solar variability and the low frequency variations of the Nile water level. The link involves the influence of solar variability on the North Annual Mode of atmospheric variability and its North Atlantic and Indian Oceans patterns that affect rainfall over Eastern Equatorial Africa where the Nile originates.

  5. Record of Nile seasonality in Nubian neonates.

    PubMed

    Martin, Céline; Maureille, Bruno; Amiot, Romain; Touzeau, Alexandra; Royer, Aurélien; Fourel, François; Panczer, Gérard; Flandrois, Jean-Pierre; Lécuyer, Christophe

    2017-06-01

    The oxygen isotope compositions of bones (n = 11) and teeth (n = 20) from 12 Sudanese individuals buried on Sai Island (Nubia) were analysed to investigate the registration of the evolution of the Nile environment from 3700 to 500 years BP and the potential effects of ontogeny on the oxygen isotope ratios. The isotopic compositions were converted into the composition of drinking water, ultimately originating from the Nile. δ(18)O values decrease during ontogeny; this is mainly related to breastfeeding and physiology. Those of neonates present very large variations. Neonates have a very high bone turnover and are thus able to record seasonal δ(18)O variations of the Nile waters. These variations followed a pattern very similar to the present one. Nile δ(18)O values increased from 1.4 to 4.4 ‰ (Vienna Standard Mean Ocean Water) from the Classic Kerma (∼3500 BP) through the Christian period (∼1000 BP), traducing a progressive drying of Northeast Africa.

  6. The question of Sudan: a hydroeconomic optimization model for the Sudanese Nile

    NASA Astrophysics Data System (ADS)

    Satti, S.; Zaitchik, B.; Siddiqui, S.

    2014-10-01

    The effects of development and the uncertainty of a changing climate in East Africa pose myriad challenges for water managers along the Blue Nile. Sudan's large irrigation potential, hydroelectric dams, and prime location within the basin mean that Sudan's water management decisions will have great social, economic and political implications within the region. At the same time, Sudan's water use options are constrained by tradeoffs between upstream irrigation developments and downstream hydropower facilities as well as by the country's commitments under existing or future transboundary water sharing agreements. Here, we present a model that can be applied to evaluate optimal allocation of surface water resources to irrigation and hydropower in the Sudanese portion of the Blue Nile. Hydrologic inputs are combined with agronomic and economic inputs to formulate an optimization model within the General Algebraic Modeling System (GAMS). A sensitivity analysis is performed by testing model response to a range of economic conditions and to changes in the volume and timing of hydrologic flows. Results indicate that changing hydroclimate inputs have the capacity to greatly influence the productivity of Sudan's water resources infrastructure. Results also show that the economically optimal volume of water consumption, and thus the importance of existing treaty constraints, is sensitive to the perceived value of agriculture relative to electricity as well as to changing hydrological conditions.

  7. A rapid-screening approach to detect and quantify microplastics based on fluorescent tagging with Nile Red

    NASA Astrophysics Data System (ADS)

    Maes, Thomas; Jessop, Rebecca; Wellner, Nikolaus; Haupt, Karsten; Mayes, Andrew G.

    2017-03-01

    A new approach is presented for analysis of microplastics in environmental samples, based on selective fluorescent staining using Nile Red (NR), followed by density-based extraction and filtration. The dye adsorbs onto plastic surfaces and renders them fluorescent when irradiated with blue light. Fluorescence emission is detected using simple photography through an orange filter. Image-analysis allows fluorescent particles to be identified and counted. Magnified images can be recorded and tiled to cover the whole filter area, allowing particles down to a few micrometres to be detected. The solvatochromic nature of Nile Red also offers the possibility of plastic categorisation based on surface polarity characteristics of identified particles. This article details the development of this staining method and its initial cross-validation by comparison with infrared (IR) microscopy. Microplastics of different sizes could be detected and counted in marine sediment samples. The fluorescence staining identified the same particles as those found by scanning a filter area with IR-microscopy.

  8. A rapid-screening approach to detect and quantify microplastics based on fluorescent tagging with Nile Red.

    PubMed

    Maes, Thomas; Jessop, Rebecca; Wellner, Nikolaus; Haupt, Karsten; Mayes, Andrew G

    2017-03-16

    A new approach is presented for analysis of microplastics in environmental samples, based on selective fluorescent staining using Nile Red (NR), followed by density-based extraction and filtration. The dye adsorbs onto plastic surfaces and renders them fluorescent when irradiated with blue light. Fluorescence emission is detected using simple photography through an orange filter. Image-analysis allows fluorescent particles to be identified and counted. Magnified images can be recorded and tiled to cover the whole filter area, allowing particles down to a few micrometres to be detected. The solvatochromic nature of Nile Red also offers the possibility of plastic categorisation based on surface polarity characteristics of identified particles. This article details the development of this staining method and its initial cross-validation by comparison with infrared (IR) microscopy. Microplastics of different sizes could be detected and counted in marine sediment samples. The fluorescence staining identified the same particles as those found by scanning a filter area with IR-microscopy.

  9. Assessment of future Nile flow through an ensemble of RCM simulations

    NASA Astrophysics Data System (ADS)

    Buontempo, Carlo; Ezzat Elshamy, Mohamed; Lørup, Jens Kristian; Jones, Richard; Butts, Mike; Betts, Richard; Hassan, Mohamed; Amin, Doaa M.; Kotb, Alaa-Eldin M.; Palin, Erika; Sanderson, Michael; McCarthy, Rachel

    2010-05-01

    The Nile represents a crucial resource for the economy of eastern and north-eastern Africa. Agriculture, energy production and livelihood in general depend strongly on the river. Assessing the impact that climate change may have on water resources is thus of critical importance for the people living in the Nile Basin. The objective of this study, carried out in close collaboration between the Ministry of Water Resources and Irrigation in Egypt, UK Met Office Hadley Centre and DHI, is to assess the possible impacts of climate change on the Nile river flow and in particular the inflow to the High Aswan Dam. Using climate models to inform water-related policies in the Nile Basin is a complex matter: the range of projections of change in both precipitation and river runoff tends to be wide with no consensus even on the sign of change. Previous studies (e.g. Conway & Hulme 1996; Strzepek & Yates 1996; Strzepek et al. 1996; Yates & Strzepek 1998) have shown the difficulty in assessing the impacts of climate change on Egyptian water resources. It is important to consider uncertainties in climate projections, since precise forecasts are not possible. Probabilistic projections have previously been generated by the Met Office Hadley Centre for the UK (the UK Climate Projections 2009, or UKCP09), involving a complex hierarchy of global and regional climate models, simple climate models and statistical techniques. Here we use an approach aligned to part of the full UKCP09 methodology, in which we perform a number of simulations with the PRECIS regional climate model driven by boundary conditions from several different variants of the HadCM3 GCM. Each of these versions was characterised by different values for a set of parameters that describe the basic unresolved physical processes (e.g. Palmer and Williams 2008) and simulate a range of plausible climate changes over the region. For this project a set of 5 GCM ensemble members was initially selected from the 17 transient runs

  10. West Nile virus surveillance in East Baton Rouge Parish, Louisiana.

    PubMed

    Gleiser, Raquel M; Mackay, Andrew J; Roy, Alma; Yates, Mathew M; Vaeth, Randy H; Faget, Guy M; Folsom, Alex E; Augustine, William F; Wells, Roderick A; Perich, Michael J

    2007-03-01

    West Nile virus (WNV) was detected for the first time in Louisiana in the fall of 2001. Surveillance data collected from East Baton Rouge Parish in 2002 were examined to establish baseline data on WNV activity, to support the current design of disease surveillance programs, and to target vector control efforts in the parish. The first indications of WNV activity were from a dead Northern Cardinal collected in February and from a live male cardinal sampled on 14 March. In mosquito pools, WNV was first detected on June 11. The onset of the first human case and the first detection of WNV in sentinel chickens occurred concurrently on June 24. The number of reported human cases and minimum infection rates in mosquitoes peaked in July. WNV prevalence in wild birds increased in late August and was highest in December. WNV-positive wild birds and mosquito pools were detected an average of 31 and 59 days in advance of the onset date of reported human cases, respectively, within 5 km of the residence of a human case. Antibodies to WNV were detected in sera from 7 (Northern Cardinal, House Sparrow, Northern Mockingbird, Blue Jay, Hermit Thrush, Yellow-rumped Warbler, and White-throated Sparrow) of the 42 wild bird species tested. Wild bird serology indicated WNV activity during the winter. Out of 18 mosquito species tested, the only species found positive for WNV was Culex quinquefasciatus, a result suggesting that this species was the primary epizootic/epidemic vector.

  11. Origin of the Sinai-Negev erg, Egypt and Israel: mineralogical and geochemical evidence for the importance of the Nile and sea level history

    USGS Publications Warehouse

    Muhs, Daniel R.; Roskin, Joel; Tsoar, Haim; Skipp, Gary; Budahn, James R.; Sneh, Amihai; Porat, Naomi; Stanley, Jean-Daniel; Katra, Itzhak; Blumberg, Dan G.

    2013-01-01

    The Sinai–Negev erg occupies an area of 13,000 km2 in the deserts of Egypt and Israel. Aeolian sand of this erg has been proposed to be derived from the Nile Delta, but empirical data supporting this view are lacking. An alternative source sediment is sand from the large Wadi El Arish drainage system in central and northern Sinai. Mineralogy of the Negev and Sinai dunes shows that they are high in quartz, with much smaller amounts of K-feldspar and plagioclase. Both Nile Delta sands and Sinai wadi sands, upstream of the dunes, also have high amounts of quartz relative to K-feldspar and plagioclase. However, Sinai wadi sands have abundant calcite, whereas Nile Delta sands have little or no calcite. Overall, the mineralogical data suggest that the dunes are derived dominantly from the Nile Delta, with Sinai wadi sands being a minor contributor. Geochemical data that proxy for both the light mineral fraction (SiO2/10–Al2O3 + Na2O + K2O–CaO) and heavy mineral fraction (Fe2O3–MgO–TiO2) also indicate a dominant Nile Delta source for the dunes. Thus, we report here the first empirical evidence that the Sinai–Negev dunes are derived dominantly from the Nile Delta. Linkage of the Sinai–Negev erg to the Nile Delta as a source is consistent with the distribution of OSL ages of Negev dunes in recent studies. Stratigraphic studies show that during the Last Glacial period, when dune incursions in the Sinai–Negev erg began, what is now the Nile Delta area was characterized by a broad, sandy, minimally vegetated plain, with seasonally dry anastomosing channels. Such conditions were ideal for providing a ready source of sand for aeolian transport under what were probably much stronger glacial-age winds. With the post-glacial rise in sea level, the Nile River began to aggrade. Post-glacial sedimentation has been dominated by fine-grained silts and clays. Thus, sea level, along with favorable climatic conditions, emerges as a major influence on the timing of dune

  12. 78 FR 33703 - Safety Zone; Great Western Tube Float; Colorado River; Parker, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-05

    ... include all navigable waters of the Colorado River from La Paz County Park to the Blue Water Resort... width of the river from La Paz County Park to the Blue Water Resort & Casino. However, vessels may... includes the waters of the Colorado River between La Paz County Park to the Blue Water Resort & Casino...

  13. West Nile virus infection in children.

    PubMed

    Barzon, Luisa; Pacenti, Monia; Sinigaglia, Alessandro; Berto, Alessandro; Trevisan, Marta; Palù, Giorgio

    2015-01-01

    West Nile virus (WNV) is an emerging flavivirus responsible for an increasing number of outbreaks of neuroinvasive disease in North America, Europe, and neighboring countries. Almost all WNV infections in humans are transmitted through the bite of infected mosquitoes. Transmission during pregnancy and through breastfeeding has been reported, but the risk seems to be very low. West Nile disease in children is less common (1-5% of all WNV cases) and associated with milder symptoms and better outcome than in elderly individuals, even though severe neuroinvasive disease and death have been reported also among children. However, the incidence of WNV infection and disease in children is probably underestimated and the disease spectrum is not fully understood because of lack of reporting and underdiagnosis in children. Infection is diagnosed by detection of WNV-specific antibodies in serum and WNV RNA in plasma and urine. Since no effective WNV-specific drugs are available, therapy is mainly supportive.

  14. Did Nile flooding sink two ancient cities?

    PubMed

    Said, Rushdi

    2002-01-03

    The discovery of the two cities of Herakleion and East Canopus under the waters of the Bay of Abu Qir (east of Alexandria, Egypt) stirred worldwide attention when it was first announced in the summer of 2000. Their disappearance some 1,250 years ago has been ascribed by Stanley, Goddio and Schnepp to a strong Nile flood that caused riverbank failure and the destruction of the two cities, rather than to the action of earthquakes, as was first proposed when the ruins were discovered. But I believe that this interpretation is flawed, because no flood could have reached the Abu Qir Bay at the time of the disappearance of the two cities, as the Canopic branch of the Nile, along whose banks they were situated, had dried to a trickle more than 200 years earlier.

  15. West Nile Virus in Farmed Alligators

    PubMed Central

    Mauel, Michael J.; Baldwin, Charles; Burtle, Gary; Ingram, Dallas; Hines, Murray E.; Frazier, Kendal S.

    2003-01-01

    Seven alligators were submitted to the Tifton Veterinary Diagnostic and Investigational Laboratory for necropsy during two epizootics in the fall of 2001 and 2002. The alligators were raised in temperature-controlled buildings and fed a diet of horsemeat supplemented with vitamins and minerals. Histologic findings in the juvenile alligators were multiorgan necrosis, heterophilic granulomas, and heterophilic perivasculitis and were most indicative of septicemia or bacteremia. Histologic findings in a hatchling alligator were random foci of necrosis in multiple organs and mononuclear perivascular encephalitis, indicative of a viral cause. West Nile virus was isolated from submissions in 2002. Reverse transcription-polymerase chain reaction (RT-PCR) results on all submitted case samples were positive for West Nile virus for one of four cases associated with the 2001 epizootic and three of three cases associated with the 2002 epizootic. RT-PCR analysis was positive for West Nile virus in the horsemeat collected during the 2002 outbreak but negative in the horsemeat collected after the outbreak. PMID:12890319

  16. When did the Nile Begin?: Remote Sensing Analysis of Paleo-drainages Near Kom Ombo, Upper Egypt

    NASA Astrophysics Data System (ADS)

    Hinz, E. A.; Stern, R. J.; Thurmond, A. K.; Abdelsalam, M. G.; Abdeen, M. M.

    2003-12-01

    The geomorphology of Southern Egypt is dominated by numerous dry riverbeds termed wadis, many of which formed before the modern transcontinental Nile began flowing north. Many of these are relict channels that formed part of an older (Late Miocene) drainage system that flowed westward from the Red Sea Hills and only drained the area of modern Egypt. This older drainage was disrupted and reworked by the modern north-flowing Nile in the mid- to late Pleistocene but is well-preserved in the hyper-arid Sahara and can be studied using remote sensing images. Various optical and radar data along with digital elevation models (DEM) extracted from Shuttle Radar Topography Mission (SRTM) data were used in combination to map and establish the chronological order of different drainage systems and to study the drainage reorganization in southern Egypt. Remote sensing analysis revealed stream capture events in the region around the city of Kom Ombo, on the northern flank of the Nubian Swell. The images show that the older, west-flowing Wadi Abu Suberia has been captured by the north-flowing wadis of Ellawi and Kharit. These streams may owe their aggressive headwater erosion to development of the east-west trending Kom Ombo graben. Analysis of SRTM DEMs shows that the drainages in southern Egypt are dominantly oriented east-west and flow into the Nile. SIR-C radar images reveal that Wadi Kubbaniya, located immediately west and across the Nile from Wadi Abu Suberia and now draining east, was once the downstream section and Wadi Abu Suberia the upstream section of the same river. This W- to NW- flowing drainage has been referred to as the Kubbaniya Nile. The Kubbaniya Nile can be traced on the SIR-C images as far north as the southernmost extent of the Gallaba Gravel Plain where it is lost under Quaternary gravel and sand deposits. Analysis of the present-day drainage using SRTM DEMs suggests that a subtle channel runs north through the Gallaba Plain and joins the Nile channel

  17. Nile River, Lake Nasser, North Sudan and Lower Egypt

    NASA Image and Video Library

    1992-11-01

    STS052-152-026 (22Oct-1 Nov 1992) --- Backdropped over eastern Egypt, the Canadian-built remote manipulator system (RMS) attached to NASA's Earth-orbiting Space Shuttle Columbia displays a Canadian Space Agency (CSA) experiment. Materials Exposure in Low Earth Orbit (MELEO) is one of a number of Canadian experiments which flew aboard Columbia for the ten-day STS-52 mission. Principal investigator for the experiment is Dr. David G. Zimick of the CSA. Plastic and composite materials used on the external surfaces of spacecraft have been found to degrade in the harsh environment of space. Evidence suggests that this degradation is caused by interaction with atomic oxygen which induces damaging chemical and physical reactions. The result is a loss in mass, strength, stiffness and stability of size and shape. During the mission, MELEO exposed over 350 material specimens mounted on "witness plates" on the RMS arm. The specimen collection will be analyzed in the weeks following the mission. Typical spacecraft materials and new developments in protective measures against atomic oxygen were tested as part of the MELEO experiment.

  18. Survival, Growth and Reproduction of Non-Native Nile Tilapia II: Fundamental Niche Projections and Invasion Potential in the Northern Gulf of Mexico

    PubMed Central

    Lowe, Michael R.; Wu, Wei; Peterson, Mark S.; Brown-Peterson, Nancy J.; Slack, William T.; Schofield, Pamela J.

    2012-01-01

    Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity (0–60, by increments of 10). These predictive models were combined with kriged seasonal salinity data derived from multiple long-term data sets to project the species' fundamental niche in Mississippi coastal waters during normal salinity years (averaged across all years) and salinity patterns in extremely wet and dry years (which might emerge more frequently under scenarios of climate change). The derived fundamental niche projections showed that during the summer, Nile tilapia is capable of surviving throughout Mississippi's coastal waters but growth and reproduction were limited to river mouths (or upriver). Overwinter survival was also limited to river mouths. The areas where Nile tilapia could survive, grow, and reproduce increased during extremely wet years (2–368%) and decreased during extremely dry years (86–92%) in the summer with a similar pattern holding for overwinter survival. These results indicate that Nile tilapia is capable of 1) using saline waters to gain access to other watersheds throughout the region and 2) establishing populations in nearshore, low-salinity waters, particularly in the western portion of coastal Mississippi. PMID:22848533

  19. Survival, growth and reproduction of non-native Nile tilapia II: fundamental niche projections and invasion potential in the northern Gulf of Mexico.

    PubMed

    Lowe, Michael R; Wu, Wei; Peterson, Mark S; Brown-Peterson, Nancy J; Slack, William T; Schofield, Pamela J

    2012-01-01

    Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity (0-60, by increments of 10). These predictive models were combined with kriged seasonal salinity data derived from multiple long-term data sets to project the species' fundamental niche in Mississippi coastal waters during normal salinity years (averaged across all years) and salinity patterns in extremely wet and dry years (which might emerge more frequently under scenarios of climate change). The derived fundamental niche projections showed that during the summer, Nile tilapia is capable of surviving throughout Mississippi's coastal waters but growth and reproduction were limited to river mouths (or upriver). Overwinter survival was also limited to river mouths. The areas where Nile tilapia could survive, grow, and reproduce increased during extremely wet years (2-368%) and decreased during extremely dry years (86-92%) in the summer with a similar pattern holding for overwinter survival. These results indicate that Nile tilapia is capable of 1) using saline waters to gain access to other watersheds throughout the region and 2) establishing populations in nearshore, low-salinity waters, particularly in the western portion of coastal Mississippi.

  20. Survival, growth and reproduction of non-native Nile tilapia II: fundamental niche projections and invasion potential in the northern Gulf of Mexico

    USGS Publications Warehouse

    Lowe, Michael R.; Wu, Wei; Peterson, Mark S.; Brown-Peterson, Nancy J.; Slack, William T.; Schofield, Pamela J.

    2012-01-01

    Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity (0–60, by increments of 10). These predictive models were combined with kriged seasonal salinity data derived from multiple long-term data sets to project the species' fundamental niche in Mississippi coastal waters during normal salinity years (averaged across all years) and salinity patterns in extremely wet and dry years (which might emerge more frequently under scenarios of climate change). The derived fundamental niche projections showed that during the summer, Nile tilapia is capable of surviving throughout Mississippi's coastal waters but growth and reproduction were limited to river mouths (or upriver). Overwinter survival was also limited to river mouths. The areas where Nile tilapia could survive, grow, and reproduce increased during extremely wet years (2–368%) and decreased during extremely dry years (86–92%) in the summer with a similar pattern holding for overwinter survival. These results indicate that Nile tilapia is capable of 1) using saline waters to gain access to other watersheds throughout the region and 2) establishing populations in nearshore, low-salinity waters, particularly in the western portion of coastal Mississippi.

  1. Use of Persistent Scatterer Interferometry to Assess Land Deformation in the Nile Delta and its Controlling Factors

    NASA Astrophysics Data System (ADS)

    Gebremichael, E.; Sultan, M.; Becker, R.; Emil, M.; Ahmed, M.; Chouinard, K.

    2015-12-01

    We applied Persistent scatterer interferometry (PSInSAR) to assess land deformation (subsidence and uplift) across the entire Nile delta and its surroundings and to identify possible causes of the observed deformation. For the purpose of the present study, 100 Envisat Advanced Synthetic Aperture Radar (ASAR; level 0) scenes that were acquired along four tracks and covering a time span of seven years (2004 to 2010) were used. The scenes extend from the Mediterranean coast in the north to Cairo city in the south. These scenes were focused using Repeat Orbit Interferometry PACkage (ROI_PAC) software and the subsequent PSI processing was done using the Stanford Method for Persistent Scatterers (StaMPS) method. A low coherence threshold (0.2) was used to decrease the impact of vegetation-related poor coherence and decorrelation of the scenes over the investigated time span. Subsidence was observed over: (1) the Demietta Nile River branch (3 to 14 mm/yr) where it intersects the Mediterranean coastline, (2) thick (~ 40 m) Holocene sediments in lake Manzala (up to 9 mm/yr), (3) reclaimed desert areas (west of Nile Delta; up to 12 mm/yr) of high groundwater extraction, (4) along parts of a previously proposed flexure line (up to 10 mm/yr), and (5) along the eastern sections of the Mediterranean coastline (up to 15.7 mm/yr). The city of Alexandria (underlain by carbonate platform) and the terminus of the Rosetta branch of the Nile River seem to experience almost no ground movement (mean subsidence of 0.28 mm/yr and 0.74 mm/yr respectively) while the cities of Ras Elbar and Port Said (underlain by thick Holocene sediment) exhibit the highest subsidence values (up to 14 mm/yr and 8.5 mm/yr respectively). The city of Cairo has also experienced subsidence in limited areas of up to 7.8 mm/yr. High spatial correlation was also observed between the subsiding areas and the Abu Madi incised valley; the largest gas field in the Nile Delta. Most of the area undergoing subsidence in the

  2. West Nile virus ecology in a tropical ecosystem in Guatemala.

    PubMed

    Morales-Betoulle, Maria E; Komar, Nicholas; Panella, Nicholas A; Alvarez, Danilo; López, María R; Betoulle, Jean-Luc; Sosa, Silvia M; Müller, María L; Kilpatrick, A Marm; Lanciotti, Robert S; Johnson, Barbara W; Powers, Ann M; Cordón-Rosales, Celia

    2013-01-01

    West Nile virus ecology has yet to be rigorously investigated in the Caribbean Basin. We identified a transmission focus in Puerto Barrios, Guatemala, and established systematic monitoring of avian abundance and infection, seroconversions in domestic poultry, and viral infections in mosquitoes. West Nile virus transmission was detected annually between May and October from 2005 to 2008. High temperature and low rainfall enhanced the probability of chicken seroconversions, which occurred in both urban and rural sites. West Nile virus was isolated from Culex quinquefasciatus and to a lesser extent, from Culex mollis/Culex inflictus, but not from the most abundant Culex mosquito, Culex nigripalpus. A calculation that combined avian abundance, seroprevalence, and vertebrate reservoir competence suggested that great-tailed grackle (Quiscalus mexicanus) is the major amplifying host in this ecosystem. West Nile virus transmission reached moderate levels in sentinel chickens during 2007, but less than that observed during outbreaks of human disease attributed to West Nile virus in the United States.

  3. Methylene blue test

    MedlinePlus

    ... determine the type or to treat methemoglobinemia , a blood disorder. ... Methemoglobinemia - methylene blue test ... Normally, methylene blue quickly lowers the level of ... Some labs use different measurements or test different samples. ...

  4. The Blue Water

    ERIC Educational Resources Information Center

    Berger, J. Joel

    1973-01-01

    Describes some of the advantages of an elementary science activity in which students discover that blowing through a straw into a bromthymol blue solution changes the color to yellow. Directions are provided for preparing the bromthymol blue solution. (JR)

  5. Blue Origin testing

    NASA Image and Video Library

    2012-04-20

    NASA Administrator Charles Bolden (r) discusses the upcoming testing of Blue Origin's BE-3 engine thrust chamber assembly with Steve Knowles, Blue Origin project manager, at the E-1 Test Stand during an April 20, 2012, visit to Stennis Space Center. Blue Origin is one of NASA's partners developing innovative systems to reach low-Earth orbit.

  6. DNA Electrochemistry with Tethered Methylene Blue

    PubMed Central

    Pheeney, Catrina G.

    2012-01-01

    Methylene blue (MB′), covalently attached to DNA through a flexible C12 alkyl linker, provides a sensitive redox reporter in DNA electrochemistry measurements. Tethered, intercalated MB′ is reduced through DNA-mediated charge transport; the incorporation of a single base mismatch at position 3, 10, or 14 of a 17-mer causes an attenuation of the signal to 62 ± 3% of the well-matched DNA, irrespective of position in the duplex. The redox signal intensity for MB′–DNA is found to be least 3-fold larger than that of Nile blue (NB)–DNA, indicating that MB′ is even more strongly coupled to the π-stack. The signal attenuation due to an intervening mismatch does, however, depend on DNA film density and the backfilling agent used to passivate the surface. These results highlight two mechanisms for reduction of MB′ on the DNA-modified electrode: reduction mediated by the DNA base pair stack and direct surface reduction of MB′ at the electrode. These two mechanisms are distinguished by their rates of electron transfer that differ by 20-fold. The extent of direct reduction at the surface can be controlled by assembly and buffer conditions. PMID:22512327

  7. Wild snakes harbor West Nile virus.

    PubMed

    Dahlin, C R; Hughes, D F; Meshaka, W E; Coleman, C; Henning, J D

    2016-12-01

    West Nile virus (WNV) has a complex eco-epidemiology with birds acting as reservoirs and hosts for the virus. Less well understood is the role of reptiles, especially in wild populations. The goal of our study was to determine whether a wild population of snakes in Pennsylvania harbored WNV. Six species of snakes were orally sampled in the summer of 2013 and were tested for the presence of WNV viral RNA using RT-PCR. Two Eastern Garter Snakes, Thamnophis sirtalis sirtalis tested positive for viral RNA (2/123, 1.62%). These results indicate a possible role for snakes in the complex transmission cycle of WNV.

  8. Alligators as West Nile Virus Amplifiers

    PubMed Central

    Klenk, Kaci; Snow, Jamie; Morgan, Katrina; Bowen, Richard; Stephens, Michael; Foster, Falicia; Gordy, Paul; Beckett, Susan; Komar, Nicholas; Gubler, Duane; Bunning, Michel

    2004-01-01

    Recent evidence suggests that American alligators (Alligator mississippiensis) may be capable of transmitting West Nile virus (WNV) to other alligators. We experimentally exposed 24 juvenile alligators to WNV parenterally or orally. All became infected, and all but three sustained viremia titers >5.0 log10 PFU/mL (a threshold considered infectious for Culex quinquefasciatus mosquitoes) for 1 to 8 days. Noninoculated tankmates also became infected. The viremia profiles and multiple routes of infection suggest alligators may play an important role in WNV transmission in areas with high population densities of juvenile alligators. PMID:15663852

  9. Alligators as West Nile virus amplifiers.

    PubMed

    Klenk, Kaci; Snow, Jamie; Morgan, Katrina; Bowen, Richard; Stephens, Michael; Foster, Falicia; Gordy, Paul; Beckett, Susan; Komar, Nicholas; Gubler, Duane; Bunning, Michel

    2004-12-01

    Recent evidence suggests that American alligators (Alligator mississippiensis) may be capable of transmitting West Nile virus (WNV) to other alligators. We experimentally exposed 24 juvenile alligators to WNV parenterally or orally. All became infected, and all but three sustained viremia titers >5.0 log10 PFU/mL (a threshold considered infectious for Culex quinquefasciatus mosquitoes) for 1 to 8 days. Noninoculated tankmates also became infected. The viremia profiles and multiple routes of infection suggest alligators may play an important role in WNV transmission in areas with high population densities of juvenile alligators.

  10. Nile damming as plausible cause of extinction and drop in abundance of deep-sea shrimp in the western Mediterranean over broad spatial scales

    NASA Astrophysics Data System (ADS)

    Cartes, J. E.; Maynou, F.; Fanelli, E.

    2011-11-01

    Greatly increased retention of flow in Nile River reservoirs was initiated in 1964, after completion of the Aswan High Dam, which induced important oceanographic changes in the Mediterranean Sea, including deep waters (below a depth of 150 m). Based on an analysis of data series starting in the 1940s/1950s, the giant red shrimp Aristaeomorpha foliacea has become locally extinct off of the Catalonian coasts (and elsewhere in the northwestern Mediterranean) at depths of 400-900 m, with a simultaneous and significant drop in the catches of red shrimp, Aristeus antennatus, in the second half of the 1960s. The extinction and sharp decline of deep-shrimp populations off Catalonian coast (at ca. 3200 km westwards from Nile Delta) followed the 1964 drop in Nile discharge with a delay of ca. 3-5 yrs (breakpoint analysis applied to data series). The breakpoints detected in the second half of 1960s both in Nile runoff and shrimps’ abundance were independent of climatic events in the study area (e.g. changes in NAO) and occurred before the increase in fishing effort off Catalonian coasts (breakpoint in 1973-1974). The Levantine Intermediate Water (LIW), inhabited by A. foliacea in the western Basin, had significant temperature (T) and salinity (S) increases in the 1950-1970 period, and Nile damming has contributed about 45% of the total S increase of Western Mediterranean deep-water masses from the 1960s to the late 1990s (Skliris and Lascaratos, 2004). This had to increase, for instance, LIW salinity at its formation site in the eastern Mediterranean. Nile damming was probably a triggering factor for the extinction/drop in abundance of deep-sea shrimp off Catalonian coasts.

  11. Preference index supported by motivation tests in Nile tilapia

    PubMed Central

    2017-01-01

    The identification of animal preferences is assumed to provide better rearing environments for the animals in question. Preference tests focus on the frequency of approaches or the time an animal spends in proximity to each item of the investigated resource during a multiple-choice trial. Recently, a preference index (PI) was proposed to differentiate animal preferences from momentary responses (Sci Rep, 2016, 6:28328, DOI: 10.1038/srep28328). This index also quantifies the degree of preference for each item. Each choice response is also weighted, with the most recent responses weighted more heavily, but the index includes the entire bank of tests, and thus represents a history-based approach. In this study, we compared this PI to motivation tests, which consider how much effort is expended to access a resource. We performed choice tests over 7 consecutive days for 34 Nile tilapia fish that presented with different colored compartments in each test. We first detected the preferred and non-preferred colors of each fish using the PI and then tested their motivation to reach these compartments. We found that fish preferences varied individually, but the results were consistent with the motivation profiles, as individual fish were more motivated (the number of touches made on transparent, hinged doors that prevented access to the resource) to access their preferred items. On average, most of the 34 fish avoided the color yellow and showed less motivation to reach yellow and red colors. The fish also exhibited greater motivation to access blue and green colors (the most preferred colors). These results corroborate the PI as a reliable tool for the identification of animal preferences. We recommend this index to animal keepers and researchers to identify an animal’s preferred conditions. PMID:28426689

  12. Nile Delta vegetation response to Holocene climate variability

    USGS Publications Warehouse

    Bernhardt, Christopher E.; Horton, Benjamin P.; Stanley, Jean-Daniel

    2012-01-01

    A 7000 yr palynologic record from Burullus Lagoon, Nile Delta, Egypt, is assessed to investigate changes in terrestrial vegetation in response to Nile flow. Previous studies in this region have shown that sea-level rise in the early to mid-Holocene, and markedly increased human land use during the past several centuries, altered vegetation in and around the lagoon. The pollen record from this study documents changes in delta vegetation that likely reflect variations in Nile flow. We suggest that Cyperaceae pollen is a sensitive marker of precipitation over the Nile headwaters and the resultant Nile flow. Decreases in Cyperaceae pollen, interpreted as a marker for diminished Nile flow, as well as the increase in relative abundance of microscopic charcoal, occurred at ca. 6000–5500, ca. 5000, ca. 4200, and ca. 3000 cal. yr B.P. (calibrated years before present). These correspond to extreme regional and global aridity events associated with a more southerly mean position of the Intertropical Convergence Zone. These changes, also recorded by other proxy studies, indicate that several marked regional drought events affected the Nile Delta region and impacted ancient Egyptian and Middle Eastern civilizations.

  13. In Vitro and In Vivo Blood-Brain Barrier Models to Study West Nile Virus Pathogenesis.

    PubMed

    Kumar, Mukesh; Nerurkar, Vivek R

    2016-01-01

    The blood-brain barrier (BBB), a specialized interface between the peripheral blood circulation and the central nervous system, specifically regulates molecular and cellular flux between the two. It plays a critical role in the maintenance of brain hemostasis. The BBB restricts the entry of pathogens into the brain, and thus its permeability is a critical factor that determines their central effects. Once the permeability of BBB is compromised, it has serious implications in the etiology of many brain pathologies including West Nile virus (WNV) disease. In this chapter, we describe protocols for preparation, maintenance, infection and permeability measurement of monolayer and bilayer in vitro BBB models to study WNV pathogenesis. We also describe Evans blue dye assay, a well-established method to test vascular permeability in vivo after WNV infection.

  14. Sharing the rivers. Overview.

    PubMed

    Postel, S

    1996-01-01

    Globally, water use has more than tripled since 1950, and the answer to this rising demand generally has been to build more and bigger water supply projects, particularly dams and river diversions. As population and consumption levels grow, more and more rivers are being dammed, diverted, or overtapped to supply increasing volumes of water to cities, industries, and farms. Among these rivers are the Nile in northeast Africa, the Ganges in south Asia, the Amu Dar'ya and Syr Dar'ya in the Aral Sea basin, the Huang He (Yellow River) in China, and the Colorado. Subsequently, such massive change in the global aquatic environment generated deterioration, decline, and in some cases, collapse in aquatic systems. In addition, competition for water is increasing not only between the human economy and the natural environment, but also between and within countries. Water scarcity is a potential source of conflict. Forces such as the depletion of resources; population growth; and unequal distribution or access can create political conflicts. Achieving more sustainable patterns of water use, restoring and maintaining the integrity of river systems, and cooperation within and between countries will not only protect the aquatic environment, but also avert conflict.

  15. Evaluation of Satellite Based Rainfall Estimation over Major River Basins in Africa

    NASA Astrophysics Data System (ADS)

    Bitew, M. M.; Gebremichael, M.

    2012-12-01

    Accuracy of satellite rainfall estimates are poorly known over Africa because of sparse ground based observations. We examined four widely used high resolution satellite products: the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) which is near-real-time (TMPA 3B42RT), the TMPA method post-real-time research version seven (TMPA 3B42v7), the Climate Prediction Center's morphing technique (CMORPH) and the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN). The main objective of the evaluation was to assess the performance of the satellite based estimates in capturing the overall climatological blueprints of rainfall over Africa at various spatio-temporal scale, and inter-comparison of the estimates across the various climatological regimes in Africa. In the tropical, complex terrain region of East Africa, the results show poor skills of satellite rainfall in capturing elevation dependent rainfall structure; microwave based CMORPH and 3B42RT estimates provide relatively accurate estimate of rainfall in high elevation areas but showed excessive overestimation in low elevation, and merging GTS-based rain gauges with the Satellite-Only products deteriorated the accuracy of rainfall estimation in high elevation areas of the Blue Nile. In this study we present the findings over seven other large and sparsely gauged river basins: Sengal (419,659 km2), Jubba (497,655 km2), Volta (407,093 km2), Ogooue (223,656 km2), Ubangi (613,202 km2) Okavango (721,277 km2) and Kasai (925,172 km2) river basins representing different topography and climate system between 250 N and 250 S. The accuracy of those products is assessed using a ground based GPCC datasets and through inter-comparision among the products between 2003 -2011 at a resolution of 25 km by 25-km and 3 hr data. Based on these datasets we present annual, seasonal and monthly spatial structure of rainfall in terms of depth, rainy days

  16. Sacred rivers: their spiritual significance in Hindu religion.

    PubMed

    Agoramoorthy, Govindasamy

    2015-06-01

    The ancient civilizations in India, China, Egypt and Mesopotamia have flourished due to large rivers that provided water for agriculture over millennia. Egypt was able to grow well because of the Nile. Similarly, Mesopotamia had two rivers namely the Tigris and the Euphrates. Likewise, India and China have several great rivers that continue to support the agrarian culture. This article discusses the sacred significance of rivers in the ancient and contemporary Indian culture with examples from popular Hindu scriptures. It also presents the ancient model of an eco-friendly check dam and its modern application with potential to mitigate future water-related problems across the drylands of India and elsewhere.

  17. Morphostructure, growth patterns, and tectonic control of the Rhone and Nile deep-sea fans: A comparison

    SciTech Connect

    Bellaiche, G.; Mart, Y. |

    1995-02-01

    The Rhone and the Nile rivers shape the sediment distribution of the Ligurian and the Levantine basins in the Mediterranean Sea, respectively. Both rivers cut huge canyons in their bed rock during the Messinian desiccation of the Mediterranean, and the subsequent early Pliocene marine transgression reached far inland both in France and in Egypt. The sediment supply of both rivers was affected by climatic variations during the Pleistocene, but whereas glacial periods were associated with reduced water flow in the Rhone, they can be correlated with enhanced flow of the Nile. The sediment distribution and accumulation patterns of both rivers built large deltas on their continental shelves during high sea level stands. During low-stands both rivers flowed as far as the shelf edge, and transported their sedimentary load through the continental slopes directly to their deep-sea fans. The patterns of sediment distribution and accumulation in the marine basins of the Ligurian and the Levantine seas were affected also by Pliocene-Quaternary tectonic activity and halokinetic offsets that led to sediment instability. The present hydrographic and sedimentological regimes of both rivers do not represent their natural potential due to artificial interference. The principal economic significance of the deep-sea fan accumulation process is the transportation of medium- and coarse-grained sediments into the deep-marine basin. Considering the effect of these sediments on stratal permeabilities and hydrocarbon potential, the presented comparative overview emphasizes recent and subrecent sedimentological aspects that are critical to petroleum exploration in active and extinct deep-sea depositional environments.

  18. 12. VIEW OF NILES TREAD LATHE. Turning down tread on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW OF NILES TREAD LATHE. Turning down tread on wheels. Wilbur Johnston, operator. - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  19. 11. VIEW OF NILES TREAD LATHE. Turning down tread on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. VIEW OF NILES TREAD LATHE. Turning down tread on wheels. Wilbur Johnston, operator. - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  20. Lidar quantification of bank erosion in Blue Earth County, Minnesota.

    PubMed

    Kessler, A C; Gupta, S C; Dolliver, H A S; Thoma, D P

    2012-01-01

    Sediment and phosphorus (P) transport from the Minnesota River Basin to Lake Pepin on the upper Mississippi River has garnered much attention in recent years. However, there is lack of data on the extent of sediment and P contributions from riverbanks vis-à-vis uplands and ravines. Using two light detection and ranging (lidar) data sets taken in 2005 and 2009, a study was undertaken to quantify sediment and associated P losses from riverbanks in Blue Earth County, Minnesota. Volume change in river valleys as a result of bank erosion amounted to 1.71 million m over 4 yr. Volume change closely followed the trend: the Blue Earth River > the Minnesota River at the county's northern edge > the Le Sueur River > the Maple River > the Watonwan River > the Big Cobb River > Perch Creek > Little Cobb River. Using fine sediment content (silt + clay) and bulk density of 37 bank samples representing three parent materials, we estimate bank erosion contributions of 48 to 79% of the measured total suspended solids at the mouth of the Blue Earth and the Le Sueur rivers. Corresponding soluble P and total P contributions ranged from 0.13 to 0.20% and 40 to 49%, respectively. Although tall banks (>3 m high) accounted for 33% of the total length and 63% of the total area, they accounted for 75% of the volume change in river valleys. We conclude that multitemporal lidar data sets are useful in estimating bank erosion and associated P contributions over large scales, and for riverbanks that are not readily accessible for conventional surveying equipment. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  1. Evaluation of regional-scale hydrological models using multiple criteria for 12 large river basins on all continents

    NASA Astrophysics Data System (ADS)

    Huang, Shaochun; Krysanova, Valentina; Hattermann, Fred; Vetter, Tobias; Flörke, Martina; Samaniego, Luis; Arheimer, Berit; Yang, Tao; van Griensven, Ann; Su, Buda; Gelfan, Alexander; Breuer, Lutz; Haberlandt, Uwe

    2016-04-01

    A good performance of hydrological impact models under historical climate and land use conditions is a prerequisite for reliable projections under climate change. The evaluation of nine regional-scale hydrological models considering monthly river discharge, long-term average seasonal dynamics and extremes was performed in the framework of the ISI-MIP project for 12 large river basins on all continents. The modelling tools include: ECOMAG, HBV, HYMOD, HYPE, mHM, SWAT, SWIM, VIC and WaterGAP3. These models were evaluated for the following basins: the Rhine and Tagus in Europe, the Niger and Blue Nile in Africa, the Ganges, Lena, Upper Yellow and Upper Yangtze in Asia, the Upper Mississippi, MacKenzie and Upper Amazon in America, and Darling in Australia. The model calibration and validation was done using WATCH climate data for all cases. The model outputs were evaluated using twelve statistical criteria to assess the fidelity of model simulations for monthly discharge, seasonal dynamics, flow duration curves, extreme floods and low flow. The reproduction of monthly discharge and seasonal dynamics was successful in all basins except the Darling, and the high flows and flood characteristics were also captured satisfactory in most cases. However, the criteria for low flow were below the thresholds in many cases. An overview of this collaborative experiment and main results on model evaluation will be presented.

  2. Human occupations and environmental changes in the Nile valley during the Holocene: The case of Kerma in Upper Nubia (northern Sudan)

    NASA Astrophysics Data System (ADS)

    Honegger, Matthieu; Williams, Martin

    2015-12-01

    Our article presents a detailed Holocene archaeological sequence from the Nile Valley at Kerma in Upper Nubia, northern Sudan. This sequence retraces the evolution of human populations thanks to the study of several sites, supported by 90 14C dates. Reconstruction of the environmental changes was supported by a study of dated stratigraphic sections located near the archaeological sites studied, and illustrates the effects on human occupation of changes in river flow and floods, which are in turn forced by climatic changes. The results shed new light on the evolutionary dynamics of the Holocene populations in Nile Valley, little known due to the numerous hiatuses in occupation. When compared with the situation in the Sahara and the rest of the Nile Valley, they confirm that the initial occupation took place ca. 10.5 kyr BP after the start of the African Humid Period, followed by a migration towards the banks of the Nile commencing 7.3 kyr BP. They also confirm the appearance of the Neolithic by ca. 8.0 kyr BP. The Kerma stratigraphic sequences show two prosperous periods (10-8 and 7-6 kyr BP) and two hiatuses in the occupation of the sites (7.5-7.1 and 6.0-5.4 kyr BP), resulting from increased aridity.

  3. Rapid strand-plain accretion in the northeastern Nile Delta in the 9th century A.D. and the demise of the port of Pelusium

    NASA Astrophysics Data System (ADS)

    Goodfriend, Glenn A.; Stanley, Daniel Jean

    1999-02-01

    An unusually large (˜1 km3) and rapid influx of Nile River sediment in the early 800s (a.d.) resulted in accretion of an extensive strand plain (6 to 15 m thick, 35 km long, and as much as 12 km wide) on the subsiding northeastern Nile Delta margin, Egypt. This event is related to blockage of the Pelusiac branch and breaking through of a new distributary to the west of present-day Port Said, probably representing initiation of the Damietta branch. The sand is of analytically identical age throughout the area and was deposited within less than ˜60 yr, as indicated by 14C and amino acid racemization analyses of Donax shells from a series of cores. Radiocarbon dates, in combination with historical accounts by Al-Jakubi, who found the strand plain already in existence when he visited the area in the late 800s, place this event in the early 800s. Nilometer flood records suggest that the sequence of great floods of 813, 816, and 820 may have been the triggering events. This sudden displacement of sand caused Pelusium, then the principal port and fortified city of the northeastern Nile Delta located at the mouth of the Pelusiac branch, to be cut off from both the Nile and the Mediterranean, and led to its decline and eventual abandonment by the 12th century, when the Crusaders arrived.

  4. Water storage changes and climate variability within the Nile Basin between 2002 and 2011

    NASA Astrophysics Data System (ADS)

    Awange, J. L.; Forootan, E.; Kuhn, M.; Kusche, J.; Heck, B.

    2014-11-01

    Understanding water storage changes within the Nile's main sub-basins and the related impacts of climate variability is an essential step in managing its water resources. The Gravity Recovery And Climate Experiment (GRACE) satellite mission provides a unique opportunity to monitor changes in total water storage (TWS) of large river basins such as the Nile. Use of GRACE-TWS changes for monitoring the Nile is, however, difficult since stronger TWS signals over the Lake Victoria Basin (LVB) and the Red Sea obscure those from smaller sub-basins making their analysis difficult to undertake. To mitigate this problem, this study employed Independent Component Analysis (ICA) to extract statistically independent TWS patterns over the sub-basins from GRACE and the Global Land Data Assimilation System (GLDAS) model. Monthly precipitation from the Tropical Rainfall Measuring Mission (TRMM) over the entire Nile Basin are also analysed by ICA. Such extraction enables an in-depth analysis of water storage changes within each sub-basin and provides a tool for assessing the influence of anthropogenic as well as climate variability caused by large scale ocean-atmosphere interactions such as the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). Our results indicate that LVB experienced effects of both anthropogenic and climate variability (i.e., a correlation of 0.56 between TWS changes and IOD at 95% confidence level) during the study period 2002-2011, with a sharp drop in rainfall between November and December 2010, the lowest during the entire study period, and coinciding with the drought that affected the Greater Horn of Africa. Ethiopian Highlands (EH) generally exhibited a declining trend in the annual rainfall over the study period, which worsened during 2007-2010, possibly contributing to the 2011 drought over GHA. A correlation of 0.56 was found between ENSO and TWS changes over EH indicating ENSO's dominant influence. TWS changes over Bar

  5. STS-56 Earth observation of the northeastern Nile Delta

    NASA Image and Video Library

    1993-04-17

    STS-56 Earth observation of the northeastern Nile Delta was photographed from the Earth-orbiting Discovery, Orbiter Vehicle (OV) 103. The branch of the Nile featured in the frame is Daimietta. The Suez Canal marks the boundary of the Nile Delta agriculture and the Sinai Desert to the right. Lake Masada, the dark waterlogged area to the west (left) of Port Said is becoming more saline as the Aswan Dam has reduced sediment downstream. This sediment reduction, according to NASA scientists studying the STS-56 photography, has resulted in increased coastal erosion and the intrusion of a salt-water lens to the ground water, particularly in the northeastern portions of the delta. Center pivot irrigation fields are located along either side of the Ramses Canal, which connects the Daimietta Nile with Great Bitter Lake. This canal has been re-dug three or four times in the past 3,000 years. Historians note that the canal's most famous use was as the departure point of the fleet of Pharaoh Necho. The fleet circumnavigated Africa clockwise from the head of the Red Sea to the Mediterranean coast of the Nile (probably the Rosetta Nile) in a three-year voyage circa 660 BC.

  6. Infectious disease. The enigma of West Nile. .

    PubMed

    Enserink, M

    2000-11-24

    Fifteen months after the 1999 outbreak of West Nile virus in New York City, which sickened 62 mostly elderly people and killed seven, scientists are still hard pressed to predict how abundant the virus will eventually become or how serious a public health threat it will pose. This summer, the human toll has been relatively mild, with just 18 cases and one death. But the virus has been found in more than 60 bird species and about a dozen mammals; in a little more than a year, it has spread to 11 states along the East Coast and the District of Columbia. And with no natural barriers to stop it, scientists can safely say that it will keep spreading.

  7. West Nile Virus Economic Impact, Louisiana, 2002

    PubMed Central

    Meltzer, Martin I.; Ratard, Raoult; Billah, Kaafee; Molinari, Noelle A.; Roy, Kakoli; Scott, R. Douglas; Petersen, Lyle R.

    2004-01-01

    West Nile virus (WNV) is transmitted by mosquitoes and can cause illness in humans ranging from mild fever to encephalitis. In 2002, a total of 4,156 WNV cases were reported in the United States; 329 were in Louisiana. To estimate the economic impact of the 2002 WNV epidemic in Louisiana, we collected data from hospitals, a patient questionnaire, and public offices. Hospital charges were converted to economic costs by using Medicare cost-to-charge ratios. The estimated cost of the Louisiana epidemic was $20.1 million from June 2002 to February 2003, including a $10.9 million cost of illness ($4.4 million medical and $6.5 million nonmedical costs) and a $9.2 million cost of public health response. These data indicate a substantial short-term cost of the WNV disease epidemic in Louisiana. PMID:15504258

  8. West Nile virus infection of birds, Mexico.

    PubMed

    Guerrero-Sánchez, Sergio; Cuevas-Romero, Sandra; Nemeth, Nicole M; Trujillo-Olivera, María Teresa Jesús; Worwa, Gabriella; Dupuis, Alan; Brault, Aaron C; Kramer, Laura D; Komar, Nicholas; Estrada-Franco, José Guillermo

    2011-12-01

    West Nile virus (WNV) has caused disease in humans, equids, and birds at lower frequency in Mexico than in the United States. We hypothesized that the seemingly reduced virulence in Mexico was caused by attenuation of the Tabasco strain from southeastern Mexico, resulting in lower viremia than that caused by the Tecate strain from the more northern location of Baja California. During 2006-2008, we tested this hypothesis in candidate avian amplifying hosts: domestic chickens, rock pigeons, house sparrows, great-tailed grackles, and clay-colored thrushes. Only great-tailed grackles and house sparrows were competent amplifying hosts for both strains, and deaths occurred in each species. Tecate strain viremia levels were higher for thrushes. Both strains produced low-level viremia in pigeons and chickens. Our results suggest that certain avian hosts within Mexico are competent for efficient amplification of both northern and southern WNV strains and that both strains likely contribute to bird deaths.

  9. Using Persistent Scatterers Interferometry to create a subsidence map of the Nile Delta in Egypt

    NASA Astrophysics Data System (ADS)

    Bouali, E. Y.; Sultan, M.; Becker, R.; Cherif, O.

    2013-12-01

    subsidence rates vary widely across the Nile Delta, with the highest rates occurring in cities near the mouth of the Damietta branch of the Nile River and around the Mansala Lagoon, such as Ras El Bar (up to 15 mm/year), Damietta (up to 10 mm/year), and Port Said (up to 7 mm/year). The complexity of these subsidence rates is spatially evident: many cities display a wide range of subsidence rates - for example Port Said, where a majority of the city is undergoing minimal to no subsidence (< 1 mm/year) there are two regions - near the Mediterranean coast and near the Mansala Lagoon - where subsidence rates are quite high (5-7 mm/year). There are also a few overall trends observed across the delta: (1) subsidence rates are greatest in the northeast region of the delta (average: > 5 mm/year) than anywhere else (e.g., average western subsidence: 1-4 mm/year) and (2) cities generally more proximal to the Mediterranean coast exhibit greater subsidence rates (average subsidence rates: Ras El Bar: 8 mm/year, Port Said: 5 mm/year, and Damietta: 6 mm/year)than cities in the middle (e.g., Mansoura and Al Mahallah: 4 mm/year) or south regions (e.g., Tanta: <4 mm/year) of the delta.

  10. Blue Ocean Thinking

    ERIC Educational Resources Information Center

    Orem, Donna

    2016-01-01

    This article describes a concept called the "blue ocean thinking strategy," developed by W. Chan Kim and Renée Mauborgne, professors at INSEAD, an international graduate school of business in France. The "blue ocean" thinking strategy considers opportunities to create new markets for services, rather than focusing solely on…

  11. Introducing the Blues.

    ERIC Educational Resources Information Center

    Sinclair, Bryan

    2000-01-01

    Discusses the history of the blues and presents a list of resources that are designed to introduce the blues, both as a feeling and as an influential part of American music and culture. Includes picture books and nonfiction for young readers, nonfiction for older readers, Web sites, and compact disks. (LRW)

  12. Blue Ocean Thinking

    ERIC Educational Resources Information Center

    Orem, Donna

    2016-01-01

    This article describes a concept called the "blue ocean thinking strategy," developed by W. Chan Kim and Renée Mauborgne, professors at INSEAD, an international graduate school of business in France. The "blue ocean" thinking strategy considers opportunities to create new markets for services, rather than focusing solely on…

  13. Templated blue phases.

    PubMed

    Ravnik, Miha; Fukuda, Jun-ichi

    2015-11-21

    Cholesteric blue phases of a chiral liquid crystal are interesting examples of self-organised three-dimensional nanostructures formed by soft matter. Recently it was demonstrated that a polymer matrix introduced by photopolymerization inside a bulk blue phase not only stabilises the host blue phase significantly, but also serves as a template for blue phase ordering. We show with numerical modelling that the transfer of the orientational order of the blue phase to the surfaces of the polymer matrix, together with the resulting surface anchoring, can account for the templating behaviour of the polymer matrix inducing the blue phase ordering of an achiral nematic liquid crystal. Furthermore, tailoring the anchoring conditions of the polymer matrix surfaces can bring about orientational ordering different from those of bulk blue phases, including an intertwined complex of the polymer matrix and topological line defects of orientational order. Optical Kerr response of templated blue phases is explored, finding large Kerr constants in the range of K = 2-10 × 10(-9) m V(-2) and notable dependence on the surface anchoring strength. More generally, the presented numerical approach is aimed to clarify the role and actions of templating polymer matrices in complex chiral nematic fluids, and further to help design novel template-based materials from chiral liquid crystals.

  14. Blue Willow Story Plates

    ERIC Educational Resources Information Center

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  15. Blue Willow Story Plates

    ERIC Educational Resources Information Center

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  16. List 47: blue honeysuckle

    USDA-ARS?s Scientific Manuscript database

    This summary presents the descriptions of a newly released blue honeysuckle (Lonicera cerulea L.) cultivar for the List of New Fruit and Nut Cultivars. This blue honeysuckle cultivar was released in Canada in 2012 and has pending Plant Breeder’s Rights Certification with Agriculture Canada. The cult...

  17. After Stroke, 'Blue' Light May Help Beat the Blues

    MedlinePlus

    ... Light May Help Beat the Blues Akin to sunlight, it could ward off depression during rehab, study ... facility used "blue" light in its lighting system. Sunlight is humans' largest source of blue-spectrum light, ...

  18. West Nile virus infection in Veneto region, Italy, 2008-2009.

    PubMed

    Barzon, L; Squarzon, L; Cattai, M; Franchin, E; Pagni, S; Cusinato, R; Palu, G

    2009-08-06

    We report here an update on human cases of West Nile virus (WNV) infection in Veneto region, northeastern Italy. In addition to two cases of WNV neuroinvasive disease notified through a surveillance programme started in September 2008, further four cases were retrospectively identified (in May 2009) by investigating patients with aseptic meningoencephalitis of unknown aetiology occurring in Veneto region in June-September 2008. All six patients had symptom onset in August-September 2008 and were resident in a wetland area close to the Po river delta in Rovigo province. Further five cases of asymptomatic WNV infection, including four residents of the same area in Rovigo, were identified in a seroprevalence study in farm workers from Veneto region. To date, no human cases have been notified in 2009.

  19. From blue jeans to blue genes.

    PubMed

    Boon, Laurence M; Vikkula, Miikka

    2009-03-01

    Cutaneous venous anomalies are common. They are blue and vary in size, number, and location and account for most consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important because they cause pain, dysfunction, destruction of adjacent tissues, and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel therapeutic approaches. John B. Mulliken, MD, envisioned a project to uncover the genetic basis of an inherited form of venous malformation in a large New England family. Recruitment of 2 young fellows resulted in a collaborative project that unraveled the searched-for gene and its mutation. This was an opening for a new era in vascular anomalies. Two blue genes' mutations were discovered, which account for most, if not all, of the inherited forms of venous anomalies, but other genes as well, for rheologically diverse lesions. Differential diagnosis and management has improved, and animal models are being made. This was achieved through the help of Dr Mulliken, who inspired 2 young investigators in blue jeans to find 2 blue genes.

  20. FROM BLUE JEANS TO BLUE GENES

    PubMed Central

    Boon, Laurence M.; Vikkula, Miikka

    2010-01-01

    Cutaneous venous anomalies are common. They are blue in color and vary in size, number and location, and account for the majority of consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important as they cause pain, dysfunction, destruction of adjacent tissues and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel therapeutic approaches. Dr Mulliken envisioned a project to uncover the genetic basis of an inherited form of venous malformation in a large New England family. Recruitment of two young fellows resulted in a collaborative project that unraveled the searched-for-gene and its mutation. This was an opening for a new era in the field of vascular anomalies. Two blue genes’ mutations were discovered, which account for the majority, if not all, of the inherited forms of venous anomalies, but other genes as well, for rheologically diverse lesions. Differential diagnosis and management has improved, and animal models are being made. This was achieved thanks to Dr Mulliken, who inspired two young investigators in blue jeans to find two blue genes. PMID:19190503

  1. The megageomorphology of the radar rivers of the eastern Sahara

    NASA Technical Reports Server (NTRS)

    Mccauley, John F.; Breed, Carol S.; Schaber, Gerald G.

    1986-01-01

    The Eastern Sahara is devoid of surface drainage; this unusual characteristic distinguishes its morphology from that of most other desert regions where running water dominates landscape development. A map derived from SIR-A/B and LANDSAT images and the literature, shows the major presently known paleodrainages in the Eastern Sahara. This compilation permits consideration of the key questions: Where did the radar rivers come from and where did they go? Analysis of SIR-A data led McCauley et al. to suggest that the radar rivers, because of their southwestward trends, once flowed into the Chad basin. This key North African feature is a regional structural low formed in the Early Cretaceous in response to initial opening of the South Atlantic. The problem of the origin of headwaters for the radar rivers was less tractable. The idea that the source areas of the radar rivers might originally have been the same as those later captured by the Nile was proposed tentatively. A more extensive review of the Cenozoic tectonic history of North Africa reveals no reason now to suppose that the Central African tributaries of the present Nile were ever connected to the large alluvial valleys in southwestern Egypt and northwestern Sudan. formed in the Early Cretaceous in response to initial opening of the South Atlantic. The problem of the origin of headwaters for the radar rivers was less tractable. The idea that the source areas of the radar rivers might originally have been the same as those (The Ethiopian Highlands) later captured by the Nile was proposed tentatively. A more extensive review of the Cenozoic tectonic history of North Africa reveals no reason now to support that the Central African tributaries of the present Nile were ever connected to the large alluvial valleys in southwestern Egypt and northwestern Sudan.

  2. Rapid antigen-capture assay to detect West Nile virus in dead corvids.

    PubMed

    Lindsay, Robbin; Barker, Ian k; Nayar, Gopi; Drebot, Michael; Calvin, Sharon; Scammell, Cherie; Sachvie, Cheril; Fleur, Tracy Scammell-La Fleur; Dibernardo, Antonia; Andonova, Maya; Artsob, Harvey

    2003-11-01

    The utility of the VecTest antigen-capture assay to detect West Nile virus (WNV) in field-collected dead corvids was evaluated in Manitoba and Ontario, Canada, in 2001 and 2002. Swabs were taken from the oropharynx, cloaca, or both of 109 American Crows, 31 Blue Jays, 6 Common Ravens, and 4 Black-billed Magpies from Manitoba, and 255 American Crows and 28 Blue Jays from Ontario. The sensitivity and specificity of the antigen-capture assay were greatest for samples from American Crows; oropharyngeal swabs were more sensitive than cloacal swabs, and interlaboratory variation in the results was minimal. The sensitivity and specificity of the VecTest using oropharyngeal swabs from crows were 83.9% and 93.6%, respectively, for Manitoba samples and 83.3% and 95.8%, respectively, for Ontario birds. The VecTest antigen-capture assay on oropharyngeal secretions from crows is a reliable and rapid diagnostic test that appears suitable for incorporation into a WNV surveillance program.

  3. Rapid Antigen-Capture Assay To Detect West Nile Virus in Dead Corvids

    PubMed Central

    Barker, Ian; Nayar, Gopi; Drebot, Michael; Calvin, Sharon; Scammell, Cherie; Sachvie, Cheryl; La Fleur, Tracy Scammell; Dibernardo, Antonia; Andonova, Maya; Artsob, Harvey

    2003-01-01

    The utility of the VecTest antigen-capture assay to detect West Nile virus (WNV) in field-collected dead corvids was evaluated in Manitoba and Ontario, Canada, in 2001 and 2002. Swabs were taken from the oropharynx, cloaca, or both of 109 American Crows, 31 Blue Jays, 6 Common Ravens, and 4 Black-billed Magpies from Manitoba, and 255 American Crows and 28 Blue Jays from Ontario. The sensitivity and specificity of the antigen-capture assay were greatest for samples from American Crows; oropharyngeal swabs were more sensitive than cloacal swabs, and interlaboratory variation in the results was minimal. The sensitivity and specificity of the VecTest using oropharyngeal swabs from crows were 83.9% and 93.6%, respectively, for Manitoba samples and 83.3% and 95.8%, respectively, for Ontario birds. The VecTest antigen-capture assay on oropharyngeal secretions from crows is a reliable and rapid diagnostic test that appears suitable for incorporation into a WNV surveillance program. PMID:14718083

  4. 78 FR 16505 - Prospective Grant of Exclusive License: Chimeric West Nile/Dengue Viruses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-15

    ...: Chimeric West Nile/Dengue Viruses AGENCY: Centers for Disease Control and Prevention (CDC), Department of... Application 61/049,342, filed 4/30/2008, entitled ``Engineered, Chimeric West Nile/Dengue Viruses;'' PCT..., filed 10/29/2010, entitled ``Chimeric West Nile/Dengue Viruses;'' and all related continuing and foreign...

  5. Blue ocean strategy.

    PubMed

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades.

  6. West Nile Virus Ecology in a Tropical Ecosystem in Guatemala

    PubMed Central

    Morales-Betoulle, Maria E.; Komar, Nicholas; Panella, Nicholas A.; Alvarez, Danilo; López, María R.; Betoulle, Jean-Luc; Sosa, Silvia M.; Müller, María L.; Kilpatrick, A. Marm; Lanciotti, Robert S.; Johnson, Barbara W.; Powers, Ann M.; Cordón-Rosales, Celia

    2013-01-01

    West Nile virus ecology has yet to be rigorously investigated in the Caribbean Basin. We identified a transmission focus in Puerto Barrios, Guatemala, and established systematic monitoring of avian abundance and infection, seroconversions in domestic poultry, and viral infections in mosquitoes. West Nile virus transmission was detected annually between May and October from 2005 to 2008. High temperature and low rainfall enhanced the probability of chicken seroconversions, which occurred in both urban and rural sites. West Nile virus was isolated from Culex quinquefasciatus and to a lesser extent, from Culex mollis/Culex inflictus, but not from the most abundant Culex mosquito, Culex nigripalpus. A calculation that combined avian abundance, seroprevalence, and vertebrate reservoir competence suggested that great-tailed grackle (Quiscalus mexicanus) is the major amplifying host in this ecosystem. West Nile virus transmission reached moderate levels in sentinel chickens during 2007, but less than that observed during outbreaks of human disease attributed to West Nile virus in the United States. PMID:23149586

  7. Safety of West Nile