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Sample records for delineating non-point source

  1. Isotopic Tracers for Delineating Non-Point Source Pollutants in Surface Water

    SciTech Connect

    Davisson, M L

    2001-03-01

    This study tested whether isotope measurements of surface water and dissolved constituents in surface water could be used as tracers of non-point source pollution. Oxygen-18 was used as a water tracer, while carbon-14, carbon-13, and deuterium were tested as tracers of DOC. Carbon-14 and carbon-13 were also used as tracers of dissolved inorganic carbon, and chlorine-36 and uranium isotopes were tested as tracers of other dissolved salts. In addition, large databases of water quality measurements were assembled for the Missouri River at St. Louis and the Sacramento-San Joaquin Delta in California to enhance interpretive results of the isotope measurements. Much of the water quality data has been under-interpreted and provides a valuable resource to investigative research, for which this report exploits and integrates with the isotope measurements.

  2. NON-POINT SOURCE POLLUTION

    EPA Science Inventory

    Non-point source pollution is a diffuse source that is difficult to measure and is highly variable due to different rain patterns and other climatic conditions. In many areas, however, non-point source pollution is the greatest source of water quality degradation. Presently, stat...

  3. Research Trends in Non Point Source during 1975-2010

    NASA Astrophysics Data System (ADS)

    Yanhua, Zhuang; Thuminh, Nguyen; Beibei, Niu; ei, Shao; Song, Hong

    According to the samples of 2924 articles about non point source of SCI and SSCI databases from 1975 to 2010, this study analysed the articles in the growth trend of article outputs, subject categories and journals, international collaborations, geographic distribution and scientific research issues by using bibliometric analysis. The results showed that non point source research steadily increased over the past 35 years and the annual number of articles published in 2010 was 79 times of that in 1975. Non point source was involved into 67 kinds of subjects and appeared in 451 journals. The main study area was concentrated in North America and Europe, following by East Asia. There were 79 countries/territories participated in non point source research, and USA was the largest contributor in non point source research and had a central position in collaboration networks. A keyword analysis indicated that water quality, non point pollutions, and watershed were the hottest issues of non point source research; "GIS, "watershed management", "modeling", "simulation", "monitoring", and "remote sensing" were the most popular research methods; and "agriculture", "land use", "runoff", and "pollution" were the leading causes of non point pollution.

  4. [A review on non-point source pollution models].

    PubMed

    Zhang, Qiu-Ling; Chen, Ying-Xu; Yu, Qiao-Gang; Deng, Hua; Tian, Ping

    2007-08-01

    With the effective control of point source pollution, the non-point source pollution (NPSP) of water environment has been paid more and more attention, and NPSP models are thriving with the development of 3S technology. This paper made a brief introduction about the classification and evolution of NPSP models. Ten NPSP models commonly used abroad were selected and compared, with their software developers and providers, data input and output, pollutant- and sediment types, time scale, simulation progress and characteristics, and model types illustrated. Based on the model applications and related literature reports, a qualitative evaluation was made from the viewpoint of the suitability of NPSP models to different watershed situation. Finally, the existing research insufficiency was analyzed, and the future development trend of non-point research was discussed, which would be helpful to the development of NPSP models and their applications in water management in China.

  5. [A landscape ecological approach for urban non-point source pollution control].

    PubMed

    Guo, Qinghai; Ma, Keming; Zhao, Jingzhu; Yang, Liu; Yin, Chengqing

    2005-05-01

    Urban non-point source pollution is a new problem appeared with the speeding development of urbanization. The particularity of urban land use and the increase of impervious surface area make urban non-point source pollution differ from agricultural non-point source pollution, and more difficult to control. Best Management Practices (BMPs) are the effective practices commonly applied in controlling urban non-point source pollution, mainly adopting local repairing practices to control the pollutants in surface runoff. Because of the close relationship between urban land use patterns and non-point source pollution, it would be rational to combine the landscape ecological planning with local BMPs to control the urban non-point source pollution, which needs, firstly, analyzing and evaluating the influence of landscape structure on water-bodies, pollution sources and pollutant removal processes to define the relationships between landscape spatial pattern and non-point source pollution and to decide the key polluted fields, and secondly, adjusting inherent landscape structures or/and joining new landscape factors to form new landscape pattern, and combining landscape planning and management through applying BMPs into planning to improve urban landscape heterogeneity and to control urban non-point source pollution.

  6. Optical Remote Sensing Method to Determine Strength of Non-point Sources

    DTIC Science & Technology

    2008-09-01

    1989. “Air Toxics Monitoring: A Comparison Between Remote Sensing and Point Monitoring Techniques,” In Proceedings of American Chemical Society ... Method to Determine Strength of Non-point Sources September 2008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden...SUBTITLE Optical Remote Sensing Method to Determine Strength of Non-point Sources 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

  7. [Study on water quality monitoring scheme based on non-point source pollution].

    PubMed

    Wu, Xi-Jun; Li, Huai-En; Li, Jia-Ke; Li, Qiang-Kun; Dong, Wen

    2013-06-01

    In order to improve standardization and normalization of non-point source pollution monitoring, this paper summarized the non-point source pollution monitoring scheme that based on conventional technology condition. The scheme firstly emphasized the preparation work before monitoring, including situation investigation and index selection of the monitoring area and so on; In the process of establishing monitoring scheme, the monitoring area was divided into three types: city, agriculture and watershed. Take urban area monitoring scheme for Xi'an as an example, through dividing function zone setting sampling point, summarized sampling time interval, frequency and sampling methods during a rainfall process. An irrigation district was an example for agricultural monitoring scheme, through unit division, setting sampling point at the approach channel and drain channel, introduced sampling times, interval time and so on in the process of irrigation. Watershed monitoring scheme's example was the Weihe GuanZhong section, raised the setting principle of each sample section, and analyzed each section's sampling law in the process of rainfall. Finally the principal character of different non-point source pollution monitoring areas was discussed, and concluded that non-point source pollution monitoring scheme is the base of non-point source pollution study and control.

  8. Modeling the contribution of point sources and non-point sources to Thachin River water pollution.

    PubMed

    Schaffner, Monika; Bader, Hans-Peter; Scheidegger, Ruth

    2009-08-15

    Major rivers in developing and emerging countries suffer increasingly of severe degradation of water quality. The current study uses a mathematical Material Flow Analysis (MMFA) as a complementary approach to address the degradation of river water quality due to nutrient pollution in the Thachin River Basin in Central Thailand. This paper gives an overview of the origins and flow paths of the various point- and non-point pollution sources in the Thachin River Basin (in terms of nitrogen and phosphorus) and quantifies their relative importance within the system. The key parameters influencing the main nutrient flows are determined and possible mitigation measures discussed. The results show that aquaculture (as a point source) and rice farming (as a non-point source) are the key nutrient sources in the Thachin River Basin. Other point sources such as pig farms, households and industries, which were previously cited as the most relevant pollution sources in terms of organic pollution, play less significant roles in comparison. This order of importance shifts when considering the model results for the provincial level. Crosschecks with secondary data and field studies confirm the plausibility of our simulations. Specific nutrient loads for the pollution sources are derived; these can be used for a first broad quantification of nutrient pollution in comparable river basins. Based on an identification of the sensitive model parameters, possible mitigation scenarios are determined and their potential to reduce the nutrient load evaluated. A comparison of simulated nutrient loads with measured nutrient concentrations shows that nutrient retention in the river system may be significant. Sedimentation in the slow flowing surface water network as well as nitrogen emission to the air from the warm oxygen deficient waters are certainly partly responsible, but also wetlands along the river banks could play an important role as nutrient sinks.

  9. [Spatial heterogeneity and classified control of agricultural non-point source pollution in Huaihe River Basin].

    PubMed

    Zhou, Liang; Xu, Jian-Gang; Sun, Dong-Qi; Ni, Tian-Hua

    2013-02-01

    Agricultural non-point source pollution is of importance in river deterioration. Thus identifying and concentrated controlling the key source-areas are the most effective approaches for non-point source pollution control. This study adopts inventory method to analysis four kinds of pollution sources and their emissions intensity of the chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in 173 counties (cities, districts) in Huaihe River Basin. The four pollution sources include livestock breeding, rural life, farmland cultivation, aquacultures. The paper mainly addresses identification of non-point polluted sensitivity areas, key pollution sources and its spatial distribution characteristics through cluster, sensitivity evaluation and spatial analysis. A geographic information system (GIS) and SPSS were used to carry out this study. The results show that: the COD, TN and TP emissions of agricultural non-point sources were 206.74 x 10(4) t, 66.49 x 10(4) t, 8.74 x 10(4) t separately in Huaihe River Basin in 2009; the emission intensity were 7.69, 2.47, 0.32 t.hm-2; the proportions of COD, TN, TP emissions were 73%, 24%, 3%. The paper achieves that: the major pollution source of COD, TN and TP was livestock breeding and rural life; the sensitivity areas and priority pollution control areas among the river basin of non-point source pollution are some sub-basins of the upper branches in Huaihe River, such as Shahe River, Yinghe River, Beiru River, Jialu River and Qingyi River; livestock breeding is the key pollution source in the priority pollution control areas. Finally, the paper concludes that pollution type of rural life has the highest pollution contribution rate, while comprehensive pollution is one type which is hard to control.

  10. HYDROLOGY AND SEDIMENT MODELING USING THE BASINS NON-POINT SOURCE MODEL

    EPA Science Inventory

    The Non-Point Source Model (Hydrologic Simulation Program-Fortran, or HSPF) within the EPA Office of Water's BASINS watershed modeling system was used to simulate streamflow and total suspended solids within Contentnea Creek, North Carolina, which is a tributary of the Neuse Rive...

  11. Simulation of Urban Runoff Non-point Source Pollution Load and Analysis on Its Influencing Factors

    NASA Astrophysics Data System (ADS)

    Li, R.; Ruan, X.

    2013-12-01

    As the point source pollution control has advanced, the proportion of urban non-point pollution caused by rainfall in urban water pollution is increasing. For quantitative evaluation of non-point source pollution in urban rivers and to study their influencing factors, this study takes the inner Qinhuai River in Nanjing as the study area. The non-point source pollution load simulation model of the study area was built based on the Storm Water Management Model (SWMM), and was calibrated using the real-time monitoring data of rainfall and the outlet of the pipes during a short duration rainfall in 2011. TSS, CODMn, TN and TP were selected as the major pollution load indicators to quantitatively assess the rainfall runoff and non-point source pollution of 328.2ha confluence area of inner Qinhuai River, emphatically probe into the variation of the rainfall runoff and non-point source pollution in response to variability in underlying surface and drainage pipes. The results show that: (1) the pollution load concentration in the outlet of the popes increases initially and then decreases, the peak concentration appears at 5~15minutes after the effluent. The concentration of TN and TP appears apparent randomness and fluctuation due to the spatial-temporal uncertainty of the distribution of the non-point source pollution. The maximum flow into the river, the total runoff, the total output of TSS, CODMn, TN and TP during a typical year rainfall in two years return period are 19.67m3/s, 81.74×103m3, 2318.59kg, 1598.08kg, 476.09kg and 24.24kg, respectively. (2)The percentage of impervious underlying surface, the slope of the underlying surface, the percentage of no depression of the impervious underlying surface and the roughness of the pipes, which are the sensitive parameters of the model, have an significant impact on the runoff and pollution load in the outlet of the pipes. Urban rainfall runoff and non-point source pollution can be reduced by reducing the percentage of

  12. [Spatial distribution and pollution source identification of agricultural non-point source pollution in Fujiang watershed].

    PubMed

    Ding, Xiao-Wen; Shen, Zhen-Yao

    2012-11-01

    In order to provide regulatory support for management and control of non-point source (NPS) pollution in Fujiang watershed, agricultural NPS pollution is simulated, spatial distribution characteristics of NPS pollution are analyzed, and the primary pollution sources are also identified, by export coefficient model (ECM) and geographic information system (GIS). Agricultural NPS total nitrogen (TN) loading was of research area was 9.11 x 10(4) t in 2010, and the average loading was intensity was 3.10 t x km(-2). Agricultural NPS TN loading mainly distributed over dry lands, Mianyang city and gentle slope areas; high loading intensity areas were dry lands, Deyang city and gentle slope areas. Agricultural land use, of which contribution rate was 62. 12%, was the most important pollution source; fertilizer loss in dry lands, of which contribution rate was 50.49%, was the prominent. Improving methods of agricultural cultivation, implementing "farm land returning to woodland" policy, and enhancing treatment efficiency of domestic sewage and livestock waster wate are effective measures.

  13. [Research on spatial characteristic of non-point source pollution in Liaohe River basin].

    PubMed

    Wang, Xue-Lei; Cai, Ming-Yong; Zhong, Bu-Qing; Yao, Yan-Juan; Yin, Shou-Jing; Wu, Di

    2013-10-01

    The spatial characteristic of non-point source pollution in the Liaohe River was studied. Coupling the remote sensing data and non-point source (NPS) models, a method of assessing NPS pollution by pixel unit was developed, aiming to analyse the NPS pollution characteristic of Liaohe River basin in 2010, in turn to identify the main polluted areas and prevention measures. The work will provide technical supports for pollution prevention in Liaohe River basin. The results showed that in 2010, the total discharge of total nitrogen (TN) was 1.03 x 10(5) t, the total phosphorus (TP) was 6.8 x 10(3) t, the chemical oxygen demand (COD) was 1.31 x 10(5) t and the ammonia nitrogen (NH+4 -N) was 1. 8 x 10(4) t. The main pollution source of NPS was from agriculture. The contributions of NPS pollution to water quality were 67.4% , 76.4% , 39.4% and 21.9% for TN, TP, COD and NH+4 -N, respectively. The south of Liaohe River basin was the most serious polluted area, followed by the northeast areas. In this research, a method was build to estimate the NPS loads based on remote sensing pixel and the spatial characteristic of non-point source pollution in Liaohe River in 2010 was analysed, which will provide support for pollution prevention in Liaohe River.

  14. [Transformation of Non-point Source Soluble Nitrogen in Simulated Drainage Ditch].

    PubMed

    Li, Qiang-kun; Song, Chang-ji; Hu, Ya-wei; Peng, Cong; Ma, Qiang; Jiang, Zheng-xi; Ju, Yi-rheng

    2016-02-15

    The drainage ditch has a compound ecosystem structure consisting of water, sediment and plants. Migration and transformation of the non-point source solute is important to study interception, control and management of agricultural non-point source pollution in the drainage ditch. Based on the experiment on static simulation of drainage ditches, the article used typical non-point source soluble nitrogen as an example to analyze the changing process of nitrogen content in water, sediment and reeds, and to study the effects of the sediment adsorption and desorption, reeds growth and death in different periods on nitrogen concentration in water. The article discussed nitrogen migration in water-sediment-reeds compound ecosystem and its influence on nitrogen concentration in water. The results showed that both adsorption and desorption in sediment and absorption and assimilation of reeds growth had effect on nitrogen concentration in water. The effect before October was reducing the nitrogen concentration in water, which was the process of nitrogen purification in water. After October, the nitrogen concentration in water increased and made it easy to form secondary nitrogen pollution. Meanwhile, the migration in the water-sediment-seeds ecosystem in simulated drainage ditch had close ties, any migration and transformation of nitrogen in a single medium or between different mediums would cause adjustment of nitrogen concentration in water.

  15. [Characteristics of non-point source pollution in Tiaoxi watershed and related affecting factors].

    PubMed

    Jin, Jing-liang; Wang, Fei-er; Dai, Lu-ying; Tian, Ping; Zhang, Zhi-jian

    2011-08-01

    By using soil and water assessment tool (SWAT) model, this paper simulated the surface runoff intensity and the export loadings of sediment particulates and nutrients via non-point source hydrological pathway in Tiaoxi watershed, and integrated with the simulation results, analyzed the temporal and spatial distribution characteristics of non-point source pollution in the watershed in 2008. In the study area, the per unit area non-point source pollution was stronger in northern region than in southern region and in eastern region than in western region, and the weakest in central region. Among the land utilization types, farmland had the biggest contribution to the sediment loading. There were significantly positive correlations between the loadings of surface runoff and associated sediment particulates and the rainfall intensity. The export loadings of nutrients through surface runoff were higher in rainy season (from June to September) than in dry season (from December to next March), and there existed significant correlations between the surface runoff loadings of sediment particulates, organic nitrogen, and nitrate and the average gradient of lands.

  16. Point and non-point microbial source pollution: A case study of Delhi

    NASA Astrophysics Data System (ADS)

    Jamwal, Priyanka; Mittal, Atul K.; Mouchel, Jean-Marie

    The present study identifies major point and non-point sources of microbial pollution during dry and wet weather in Delhi watershed which is the first prerequisite for planning and management of water quality of the river Yamuna. Fecal coliforms (FC) and fecal streptococci (FS) levels were determined from two types of sources - point source (effluent from sewage treatment plants) and non-point source (stormwater runoff during dry and wet weather). FC and FS levels in the river Yamuna were also monitored, which is an ultimate sink for all microbial loads in Delhi watershed. Effluent from sewage treatment plants (STPs) employing different treatment technologies were evaluated. FC and FS levels greater than the effluent discharge standard (1000 MPN/100 ml) were observed in the effluents from all STPs except “oxidation pond Timarpur”. This study also involved field program for characterization of urban runoff from different land-uses. Results indicated that the microbial quality of urban runoff produced during wet weather from different land-uses was similar to that of raw sewage. Sewage overflows along with human and animal sources were responsible for high FC and FS levels in the runoff samples. Wet weather FC and FS levels in river Yamuna were higher as compared to the dry weather levels suggesting that dilution of the river water during wet weather does not affect its microbiological quality. Thus on the basis of this study it was found that urban runoff also contributes to the microbial quality of the river Yamuna.

  17. Quantification and index of non-point source pollution in Taihu Lake region with GIS.

    PubMed

    Guo, H Y; Wang, X R; Zhu, J G

    2004-01-01

    The contribution of phosphorus and nitrogen from non-point source pollution (NPS) in the Taihu Lake region was investigated through case study and surveying in the town of Xueyan, From experimental results coupled with survey and statistics in the studied area, the distribution of nitrogen and phosphorus input to the water body is achieved from four main sources: agricultural land, village, the town center and the poultry factory. The results showed that about 38% of total phosphorus (TP) and 48% of total nitrogen (TN) discharged is from agricultural land, 33% of TP and 40% TN from village residents, 25% of TP and 10% of TN from the town center and 4% of TP and 2% of TN from the poultry factory. The Agricultural Non-point Pollution Potential Index (APPI) system for identifying and ranking critical areas of NPS was established with a Geographic Information Systems (GIS)-based technology. Quantification of the key factors in non-point sources pollution was carried out utilizing the following: Sediment Production Index (SPI), Runoff Index (RI), People and Animal Loading Index (PALI) and Chemical Use Index (CUI). These are the core parts of the model, and the weighting factor of each index was evaluated according the results of quantification. The model was successfully applied for evaluating APPI in Xueyan. Results from the model showed that the critical area identified for NPS control in Xueyan. The model has several advantages including: requiring fewer parameters, easy acquirement of these parameters, friendly interface, and convenience of operation. In addition it is especially useful for identifying critical areas of NPS when the basic data are not fully accessible, which is the present situation in China.

  18. Uncertainty Analysis of non-point source pollution control facilities design techniques in Korea

    NASA Astrophysics Data System (ADS)

    Lee, J.; Okjeong, L.; Gyeong, C. B.; Park, M. W.; Kim, S.

    2015-12-01

    The design of non-point sources control facilities in Korea is divided largely by the stormwater capture ratio, the stormwater load capture ratio, and the pollutant reduction efficiency of the facility. The stormwater capture ratio is given by a design formula as a function of the water quality treatment capacity, the greater the capacity, the more the amount of stormwater intercepted by the facility. The stormwater load capture ratio is defined as the ratio of the load entering the facility of the total pollutant load generated in the target catchment, and is given as a design formula represented by a function of the stormwater capture ratio. In order to estimate the stormwater capture ratio and load capture ratio, a lot of quantitative analysis of hydrologic processes acted in pollutant emission is required, but these formulas have been applied without any verification. Since systematic monitoring programs were insufficient, verification of these formulas was fundamentally impossible. However, recently the Korean ministry of Environment has conducted an long-term systematic monitoring project, and thus the verification of the formulas became possible. In this presentation, the stormwater capture ratio and load capture ratio are re-estimated using actual TP data obtained from long-term monitoring program at Noksan industrial complex located in Busan, Korea. Through the re-estimated process, the uncertainty included in the design process that has been applied until now will be shown in a quantitative extent. In addition, each uncertainty included in the stormwater capture ratio estimation and in the stormwater load capture ratio estimation will be expressed to quantify the relative impact on the overall non-point pollutant control facilities design process. Finally, the SWMM-Matlab interlocking module for model parameters estimation will be introduced. Acknowledgement This subject is supported by Korea Ministry of Environment as "The Eco Innovation Project : Non-point

  19. [Urban non-point source pollution control by runoff retention and filtration pilot system].

    PubMed

    Bai, Yao; Zuo, Jian-E; Gan, Li-Li; Low, Thong Soon; Miao, Heng-Feng; Ruan, Wen-Quan; Huang, Xia

    2011-09-01

    A runoff retention and filtration pilot system was designed and the long-term purification effect of the runoff was monitored. Runoff pollution characters in 2 typical events and treatment effect of the pilot system were analyzed. The results showed that the runoff was severely polluted. Event mean concentrations (EMCs) of SS, COD, TN and TP in the runoff were 361, 135, 7.88 and 0.62 mg/L respectively. The runoff formed by long rain presented an obvious first flush effect. The first 25% flow contributed more than 50% of the total pollutants loading of SS, TP, DTP and PO4(3-). The pilot system could reduce 100% of the non-point source pollution if the volume of the runoff was less than the retention tank. Otherwise the overflow will be purification by the filtration pilot system and the removal rates of SS, COD, TN, TP, DTP and PO4(3-) reached 97.4% , 61.8%, 22.6%, 85.1%, 72.1%, and 85.2% respectively. The system was stable and the removal rate of SS, COD, TN, and TP were 98.6%, 65.4%, 55.1% and 92.6%. The whole system could effectively remove the non-point source pollution caused by runoff.

  20. Presence of pathogens and indicator microbes at a non-point source subtropical recreational marine beach.

    PubMed

    Abdelzaher, Amir M; Wright, Mary E; Ortega, Cristina; Solo-Gabriele, Helena M; Miller, Gary; Elmir, Samir; Newman, Xihui; Shih, Peter; Bonilla, J Alfredo; Bonilla, Tonya D; Palmer, Carol J; Scott, Troy; Lukasik, Jerzy; Harwood, Valerie J; McQuaig, Shannon; Sinigalliano, Chris; Gidley, Maribeth; Plano, Lisa R W; Zhu, Xiaofang; Wang, John D; Fleming, Lora E

    2010-02-01

    Swimming in ocean water, including ocean water at beaches not impacted by known point sources of pollution, is an increasing health concern. This study was an initial evaluation of the presence of indicator microbes and pathogens and the association among the indicator microbes, pathogens, and environmental conditions at a subtropical, recreational marine beach in south Florida impacted by non-point sources of pollution. Twelve water and eight sand samples were collected during four sampling events at high or low tide under elevated or reduced solar insolation conditions. The analyses performed included analyses of fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli, enterococci, and Clostridium perfringens), human-associated microbial source tracking (MST) markers (human polyomaviruses [HPyVs] and Enterococcus faecium esp gene), and pathogens (Vibrio vulnificus, Staphylococcus aureus, enterovirus, norovirus, hepatitis A virus, Cryptosporidium spp., and Giardia spp.). The enterococcus concentrations in water and sand determined by quantitative PCR were greater than the concentrations determined by membrane filtration measurement. The FIB concentrations in water were below the recreational water quality standards for three of the four sampling events, when pathogens and MST markers were also generally undetectable. The FIB levels exceeded regulatory guidelines during one event, and this was accompanied by detection of HPyVs and pathogens, including detection of the autochthonous bacterium V. vulnificus in sand and water, detection of the allochthonous protozoans Giardia spp. in water, and detection of Cryptosporidium spp. in sand samples. The elevated microbial levels were detected at high tide and under low-solar-insolation conditions. Additional sampling should be conducted to further explore the relationships between tidal and solar insolation conditions and between indicator microbes and pathogens in subtropical recreational marine waters impacted

  1. A method to analyze "source-sink" structure of non-point source pollution based on remote sensing technology.

    PubMed

    Jiang, Mengzhen; Chen, Haiying; Chen, Qinghui

    2013-11-01

    With the purpose of providing scientific basis for environmental planning about non-point source pollution prevention and control, and improving the pollution regulating efficiency, this paper established the Grid Landscape Contrast Index based on Location-weighted Landscape Contrast Index according to the "source-sink" theory. The spatial distribution of non-point source pollution caused by Jiulongjiang Estuary could be worked out by utilizing high resolution remote sensing images. The results showed that, the area of "source" of nitrogen and phosphorus in Jiulongjiang Estuary was 534.42 km(2) in 2008, and the "sink" was 172.06 km(2). The "source" of non-point source pollution was distributed mainly over Xiamen island, most of Haicang, east of Jiaomei and river bank of Gangwei and Shima; and the "sink" was distributed over southwest of Xiamen island and west of Shima. Generally speaking, the intensity of "source" gets weaker along with the distance from the seas boundary increase, while "sink" gets stronger.

  2. [Nitrogen non-point source pollution identification based on ArcSWAT in Changle River].

    PubMed

    Deng, Ou-Ping; Sun, Si-Yang; Lü, Jun

    2013-04-01

    The ArcSWAT (Soil and Water Assessment Tool) model was adopted for Non-point source (NPS) nitrogen pollution modeling and nitrogen source apportionment for the Changle River watershed, a typical agricultural watershed in Southeast China. Water quality and hydrological parameters were monitored, and the watershed natural conditions (including soil, climate, land use, etc) and pollution sources information were also investigated and collected for SWAT database. The ArcSWAT model was established in the Changle River after the calibrating and validating procedures of the model parameters. Based on the validated SWAT model, the contributions of different nitrogen sources to river TN loading were quantified, and spatial-temporal distributions of NPS nitrogen export to rivers were addressed. The results showed that in the Changle River watershed, Nitrogen fertilizer, nitrogen air deposition and nitrogen soil pool were the prominent pollution sources, which contributed 35%, 32% and 25% to the river TN loading, respectively. There were spatial-temporal variations in the critical sources for NPS TN export to the river. Natural sources, such as soil nitrogen pool and atmospheric nitrogen deposition, should be targeted as the critical sources for river TN pollution during the rainy seasons. Chemical nitrogen fertilizer application should be targeted as the critical sources for river TN pollution during the crop growing season. Chemical nitrogen fertilizer application, soil nitrogen pool and atmospheric nitrogen deposition were the main sources for TN exported from the garden plot, forest and residential land, respectively. However, they were the main sources for TN exported both from the upland and paddy field. These results revealed that NPS pollution controlling rules should focus on the spatio-temporal distribution of NPS pollution sources.

  3. [Zoning planning in non-point source pollution control in Hanyang district].

    PubMed

    Yang, Liu; Ma, Ke-Ming; Guo, Qing-Hai; Zhao, Jing-Zhu; Luo, Yong-Feng

    2006-01-01

    It is most important for managing urban non-point source (NPS) pollution, actualizing the urban sustainable development as well, that zoning planning of urban NPS pollution control is studied. A case study on principles and methods of zoning planning in urban NPS pollution is carried out. Principles of urban sustainable development, priority of urban NPS pollution sensitivity, similarity of urban NPS control direction and region conjugate are put forward. Besides, it is for the first time that a more quantitive method is presented, in the case of Hanyang district, Wuhan city, which is based on L-THIA model and spatial analysis technique in GIS. Assessment of NPS pollution status quo, as well as analysis of NPS sensitivity, is the kernel component of the quantitive method. Hanyang might be divided into four NPS pollution control zones. It is helpful for decision-making of regional NPS pollution control.

  4. Current status of agricultural and rural non-point source Pollution assessment in China.

    PubMed

    Ongley, Edwin D; Xiaolan, Zhang; Tao, Yu

    2010-05-01

    Estimates of non-point source (NPS) contribution to total water pollution in China range up to 81% for nitrogen and to 93% for phosphorus. We believe these values are too high, reflecting (a) misuse of estimation techniques that were developed in America under very different conditions and (b) lack of specificity on what is included as NPS. We compare primary methods used for NPS estimation in China with their use in America. Two observations are especially notable: empirical research is limited and does not provide an adequate basis for calibrating models nor for deriving export coefficients; the Chinese agricultural situation is so different than that of the United States that empirical data produced in America, as a basis for applying estimation techniques to rural NPS in China, often do not apply. We propose a set of national research and policy initiatives for future NPS research in China.

  5. [L-THIA-based management design for controlling urban non-point source pollution].

    PubMed

    Guo, Qing-Hai; Yang, Liu; Ke-Ming, Ma

    2007-11-01

    L-THIA Model was used to simulate the amounts of NPS pollutants in 2 catchments of Sanjiao watershed (Sj1, Sj2) in Hanyang district, and the total simulated amount of NPS loads in Sj1 and Sj2 were 1.82 x 10(4) kg, 1.38 x 10(5) kg, respectively. Based on the theory of resource-sink" and interaction of pattern with process, a series of BMPs, including green roof, grassland, porous pavement, infiltration trench, vegetative filter strip and wet pond, were optimized, and effects of BMPs were simulated along the surface runoff pathway. The results show that total pollutants outputs entering Sj1 and Sj2 account for 14.65% and 6.57%, respectively. Combining L-THIA model and BMPs in series is a proper measure for non-point source pollution control and urban development planning at watershed or region scale.

  6. [Impacts of the urbanization on waters non-point source pollution].

    PubMed

    Yang, Liu; Ma, Ke-Ming; Guo, Qing-hai; Zhao, Jing-zhu

    2004-11-01

    Non-point source (NPS) pollution is the prominent source of water pollution in many countries, included America and China, of the world. Urban NPS pollution was attached little importance for long, compared with agriculture NPS pollution. While urbanization is the dominant form of land-use change in terms of impacts on water quality, the hydrology, other physical properties of watersheds as well as their NPS pollution potential at present. The formation of urban NPS pollution of water could be described by "source-process-sink". Urbanization has changed the source, process and sink of urban NPS pollution. A review was conducted on the international researches of urbanization impacts on NPS pollution in urban water environment from the point of view of "describe-predict and evaluation-application". The studies of urbanization impacts on urban NPS pollution were focused on modeling the process of urban NPS pollution by hydrologic model, predicting the pollutants load of NPS pollution. It is a fresh methodology that the relationship between urbanization and urban NPS pollution of water was analyzed by the method of landscape change and ecological process. The research on temporal-spatial comprehensive impacts of landscape pattern changes, led by urbanization, on the urban NPS pollution will be one of the hotspots.

  7. Landscape Planning for Agricultural Non-Point Source Pollution Reduction. II. Balancing Watershed Size, Number of Watersheds, and Implementation Effort

    NASA Astrophysics Data System (ADS)

    Maxted, Jeffrey T.; Diebel, Matthew W.; Vander Zanden, M. Jake

    2009-01-01

    Agricultural non-point source (NPS) pollution poses a severe threat to water quality and aquatic ecosystems. In response, tremendous efforts have been directed toward reducing these pollution inputs by implementing agricultural conservation practices. Although conservation practices reduce pollution inputs from individual fields, scaling pollution control benefits up to the watershed level (i.e., improvements in stream water quality) has been a difficult challenge. This difficulty highlights the need for NPS reduction programs that focus efforts within target watersheds and at specific locations within target watersheds, with the ultimate goal of improving stream water quality. Fundamental program design features for NPS control programs—i.e., number of watersheds in the program, total watershed area, and level of effort expended within watersheds—have not been considered in any sort of formal analysis. Here, we present an optimization model that explores the programmatic and environmental trade-offs between these design choices. Across a series of annual program budgets ranging from 2 to 200 million, the optimal number of watersheds ranged from 3 to 27; optimal watershed area ranged from 29 to 214 km2; and optimal expenditure ranged from 21,000 to 35,000/km2. The optimal program configuration was highly dependent on total program budget. Based on our general findings, we delineated hydrologically complete and spatially independent watersheds ranging in area from 20 to 100 km2. These watersheds are designed to serve as implementation units for a targeted NPS pollution control program currently being developed in Wisconsin.

  8. Landscape planning for agricultural non-point source pollution reduction. II. Balancing watershed size, number of watersheds, and implementation effort.

    PubMed

    Maxted, Jeffrey T; Diebel, Matthew W; Vander Zanden, M Jake

    2009-01-01

    Agricultural non-point source (NPS) pollution poses a severe threat to water quality and aquatic ecosystems. In response, tremendous efforts have been directed toward reducing these pollution inputs by implementing agricultural conservation practices. Although conservation practices reduce pollution inputs from individual fields, scaling pollution control benefits up to the watershed level (i.e., improvements in stream water quality) has been a difficult challenge. This difficulty highlights the need for NPS reduction programs that focus efforts within target watersheds and at specific locations within target watersheds, with the ultimate goal of improving stream water quality. Fundamental program design features for NPS control programs--i.e., number of watersheds in the program, total watershed area, and level of effort expended within watersheds--have not been considered in any sort of formal analysis. Here, we present an optimization model that explores the programmatic and environmental trade-offs between these design choices. Across a series of annual program budgets ranging from $2 to $200 million, the optimal number of watersheds ranged from 3 to 27; optimal watershed area ranged from 29 to 214 km(2); and optimal expenditure ranged from $21,000 to $35,000/km(2). The optimal program configuration was highly dependent on total program budget. Based on our general findings, we delineated hydrologically complete and spatially independent watersheds ranging in area from 20 to 100 km(2). These watersheds are designed to serve as implementation units for a targeted NPS pollution control program currently being developed in Wisconsin.

  9. Mapping the scientific research on non-point source pollution: a bibliometric analysis.

    PubMed

    Yang, Beibei; Huang, Kai; Sun, Dezhi; Zhang, Yue

    2017-02-01

    A bibliometric analysis was conducted to examine the progress and future research trends of non-point source (NPS) pollution during the years 1991-2015 based on the Science Citation Index Expanded (SCI-Expanded) of Web of Science (WoS). The publications referencing NPS pollution were analyzed including the following aspects: document type, publication language, publication output and characteristics, subject category, source journal, distribution of country and institution, author keywords, etc. The results indicate that the study of NPS pollution demonstrated a sharply increasing trend since 1991. Article and English were the most commonly used document type and language. Environmental sciences and ecology, water resources, and engineering were the top three subject categories. Water science and technology ranked first in distribution of journal, followed by Science of the total environment and Environmental Monitoring and Assessment. The USA took a leading position in both quantity and quality, playing an important role in the research field of NPS pollution, followed by the UK and China. The most productive institution was the Chinese Academy of Sciences (Chinese Acad Sci), followed by Beijing Normal University and US Department of Agriculture's Agricultural Research Service (USDA ARS). The analysis of author keywords indicates that the major hotspots of NPS pollution from 1991 to 2015 contained "water," "model," "agriculture," "nitrogen," "phosphorus," etc. The results provide a comprehensive understanding of NPS pollution research and help readers to establish the future research directions.

  10. Optimization strategy integrity for watershed agricultural non-point source pollution control based on Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Gong, Y.; Yu, Y. J.; Zhang, W. Y.

    2016-08-01

    This study has established a set of methodological systems by simulating loads and analyzing optimization strategy integrity for the optimization of watershed non-point source pollution control. First, the source of watershed agricultural non-point source pollution is divided into four aspects, including agricultural land, natural land, livestock breeding, and rural residential land. Secondly, different pollution control measures at the source, midway and ending stages are chosen. Thirdly, the optimization effect of pollution load control in three stages are simulated, based on the Monte Carlo simulation. The method described above is applied to the Ashi River watershed in Heilongjiang Province of China. Case study results indicate that the combined three types of control measures can be implemented only if the government promotes the optimized plan and gradually improves implementation efficiency. This method for the optimization strategy integrity for watershed non-point source pollution control has significant reference value.

  11. Reducing future non-point source sediment and phosphorus loading under intensifying agricultural production in the Ethiopian highlands

    NASA Astrophysics Data System (ADS)

    Mogus, Mamaru; Schmitter, Petra; Tilahun, Seifu; Steenhuise, Tammo

    2016-04-01

    Intensification of agriculture will bring along non-point source pollution in the Ethiopian highlands resulting in eutrophication of lakes. The first signs of eutrophication have been observed already in Lake Tana. The lake it supports the lives of millions in the surrounding through fishing, tourism, transportation and hydropower.Presently, information on non-point source pollution is lacking in the Ethiopian highlands. There are few studies carried out in the highlands on the extent and the source areas of pollution, and models are not available for predicting sediment and phosphorus loading other than those developed for temperate climates. The objective of this chapter is to review existing non-point source studies, report on our findings of sediment and phosphorus sources that are related the non-point source pollution of Lake Tana and to present a non-point source model for the Ethiopian highland based on the Parameter Efficient Semi-distributed Watershed Hydrology Model (PED-WHM).In our research we have found that the saturation excess runoff from valley bottoms and from degraded lands are prevalent in the Ethiopia highlands. The periodically runoff source areas are also the sources for the non-point source pollution and by concentrating best management practices in these source areas we expect that we can reduce pollution without affecting the profitability of the existing farms. The water balance component of the non-point source model has been performing well in predicting both the discharge and the location of the runoff source areas. Sediment and phosphorus prediction models have been developed and are currently being tested for the 7km2Awramba watershed and the 1350 km2Gumara basin. Initial results indicate that 11.2 ton/ha/year sediment load and an accumulation rate of 17.3 mg/kg/year of dissolved phosphorus from Gumara watershed joining the lake. By developing best management practices at this time before non-point source pollution is rampant and

  12. Parameter uncertainty analysis of non-point source pollution from different land use types.

    PubMed

    Shen, Zhen-yao; Hong, Qian; Yu, Hong; Niu, Jun-feng

    2010-03-15

    Land use type is one of the most important factors that affect the uncertainty in non-point source (NPS) pollution simulation. In this study, seventeen sensitive parameters were screened from the Soil and Water Assessment Tool (SWAT) model for parameter uncertainty analysis for different land use types in the Daning River Watershed of the Three Gorges Reservoir area, China. First-Order Error Analysis (FOEA) method was adopted to analyze the effect of parameter uncertainty on model outputs under three types of land use, namely, plantation, forest and grassland. The model outputs selected in this study consisted of runoff, sediment yield, organic nitrogen (N), and total phosphorus (TP). The results indicated that the uncertainty conferred by the parameters differed among the three land use types. In forest and grassland, the parameter uncertainty in NPS pollution was primarily associated with runoff processes, but in plantation, the main uncertain parameters were related to runoff process and soil properties. Taken together, the study suggested that adjusting the structure of land use and controlling fertilizer use are helpful methods to control the NPS pollution in the Daning River Watershed.

  13. Agricultural non-point source pollution in China: causes and mitigation measures.

    PubMed

    Sun, Bo; Zhang, Linxiu; Yang, Linzhang; Zhang, Fusuo; Norse, David; Zhu, Zhaoliang

    2012-06-01

    Non-point source (NPS) pollution has been increasingly serious in China since the 1990s. The increases of agricultural NPS pollution in China is evaluated for the period 2000-2008 by surveying the literature on water and soil pollution from fertilizers and pesticides, and assessing the surplus nitrogen balance within provinces. The main causes for NPS pollution were excessive inputs of nitrogen fertilizer and pesticides, which were partly the result of the inadequate agricultural extension services and the rapid expansion of intensive livestock production with little of waste management. The annual application of synthetic nitrogen fertilizers and pesticides in China increased by 50.7 and 119.7%, respectively, during 1991-2008. The mitigation measures to reduce NPS pollution include: correct distortion in fertilizer prices; improve incentives for the recycling of organic manure; provide farmers with better information on the sound use of agro-chemicals; and tighten the regulations and national standards on organic waste disposal and pesticides use.

  14. Model AVSWAT apropos of simulating non-point source pollution in Taihu lake basin.

    PubMed

    Zhang, Qiu-Ling; Chen, Ying-Xu; Jilani, Ghulam; Shamsi, Imran Haider; Yu, Qiao-Gang

    2010-02-15

    Accelerated eutrophication and nutrient loads in the lakes are of major concern for human health and environment. This study was undertaken for modeling the non-point source pollution of Taihu lake basin in eastern China. The SWAT model having an interface in ArcView GIS was employed. Model sensitive parameters related to hydrology and water quality were obtained by sensitivity analysis, and then calibrated and validated by comparing model predictions with field data. The GIS showed good potential for parameterization of hill-slopes, channels, and representative slope profiles for SWAT model simulations. In a monthly and daily time step, the model's Nash-Sutcliffe coefficient (E) and the coefficient of determination (R(2)) indicated that values of simulated runoff, NH(4)(+)-N and total phosphorus were acceptably closer to the measured data. Surface water parameters especially CN, Soil-AWC and ESCO were the most sensitive and had more recognition in the model. It is concluded that runoff carrying N and P nutrients from chemical fertilizer inputs in agricultural areas is the major contributor to NPSP in the lake basin. So, decrease in excessive use of N and P fertilizers and their synergism with organic manures is recommended that would significantly reduce nutrient pollution in the lake ecosystem.

  15. Identification of critical source areas for non-point source pollution in Miyun reservoir watershed near Beijing, China.

    PubMed

    Ou, Yang; Wang, Xiaoyan

    2008-01-01

    Miyun Reservoir is the major water source for Bijing, China. Currently, the water quality of Miyun reservoir is meso-trophic, mainly due to the non-point source pollution (NPS) in the watershed. Phosphorus (P) is the limited factor. In this paper, Chaohe River basin, upstream of the Miyun Reservoir, is chosen as the study area, A modified P Index was developed to identify critical source areas (CSAs) of non-point source pollution by analyzing local hydrological and meteorological data, land use, soil, soil conservation, farmland management, population density, and livestock. The factors of livestock and population density are new factors added to the P Index system based on the actual local characteristics. It was found that the loss P from high-risk area accounts for only 7.95%. These areas are located mainly along streams. Livestock factor and the population density factor are most closely related to the CSAs downstream of Chaohe River basin. The management strategies are outlined according to the distribution characteristics of the critical source areas.

  16. Integrated watershed economic model for non-point source pollution management in Upper Big Walnut Creek Watershed, OH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Today, non-point source pollution (NPS) is one of the major sources of water quality impairments globally (UNEP, 2007). In the US, nutrient pollution is the leading cause of water quality issues in lakes and estuaries (USEPA, 2002). The maximum concentration of nutrients in streams is found to be in...

  17. Evaluation of a non-point source pollution model, AnnAGNPS, in a tropical watershed

    USGS Publications Warehouse

    Polyakov, V.; Fares, A.; Kubo, D.; Jacobi, J.; Smith, C.

    2007-01-01

    Impaired water quality caused by human activity and the spread of invasive plant and animal species has been identified as a major factor of degradation of coastal ecosystems in the tropics. The main goal of this study was to evaluate the performance of AnnAGNPS (Annualized Non-Point Source Pollution Model), in simulating runoff and soil erosion in a 48 km2 watershed located on the Island of Kauai, Hawaii. The model was calibrated and validated using 2 years of observed stream flow and sediment load data. Alternative scenarios of spatial rainfall distribution and canopy interception were evaluated. Monthly runoff volumes predicted by AnnAGNPS compared well with the measured data (R2 = 0.90, P < 0.05); however, up to 60% difference between the actual and simulated runoff were observed during the driest months (May and July). Prediction of daily runoff was less accurate (R2 = 0.55, P < 0.05). Predicted and observed sediment yield on a daily basis was poorly correlated (R2 = 0.5, P < 0.05). For the events of small magnitude, the model generally overestimated sediment yield, while the opposite was true for larger events. Total monthly sediment yield varied within 50% of the observed values, except for May 2004. Among the input parameters the model was most sensitive to the values of ground residue cover and canopy cover. It was found that approximately one third of the watershed area had low sediment yield (0-1 t ha-1 y-1), and presented limited erosion threat. However, 5% of the area had sediment yields in excess of 5 t ha-1 y-1. Overall, the model performed reasonably well, and it can be used as a management tool on tropical watersheds to estimate and compare sediment loads, and identify "hot spots" on the landscape. ?? 2007 Elsevier Ltd. All rights reserved.

  18. Temporal-spatial distribution of non-point source pollution in a drinking water source reservoir watershed based on SWAT

    NASA Astrophysics Data System (ADS)

    Wang, M.; Cheng, W.; Yu, B.-S.; Fang, Y.

    2015-05-01

    The conservation of drinking water source reservoirs has a close relationship between regional economic development and people's livelihood. Research on the non-point pollution characteristics in its watershed is crucial for reservoir security. Tang Pu Reservoir watershed was selected as the study area. The non-point pollution model of Tang Pu Reservoir was established based on the SWAT (Soil and Water Assessment Tool) model. The model was adjusted to analyse the temporal-spatial distribution patterns of total nitrogen (TN) and total phosphorus (TP). The results showed that the loss of TN and TP in the reservoir watershed were related to precipitation in flood season. And the annual changes showed an "M" shape. It was found that the contribution of loss of TN and TP accounted for 84.5% and 85.3% in high flow years, and for 70.3% and 69.7% in low flow years, respectively. The contributions in normal flow years were 62.9% and 63.3%, respectively. The TN and TP mainly arise from Wangtan town, Gulai town, and Wangyuan town, etc. In addition, it was found that the source of TN and TP showed consistency in space.

  19. Coupling transfer function and GIS for assessing non-point-source groundwater vulnerability at regional scale

    NASA Astrophysics Data System (ADS)

    Coppola, A.; Comegna, V.; de Simone, L.

    2009-04-01

    Non-point source (NPS) pollution in the vadose zone is a global environmental problem. The knowledge and information required to address the problem of NPS pollutants in the vadose zone cross several technological and sub disciplinary lines: spatial statistics, geographic information systems (GIS), hydrology, soil science, and remote sensing. The main issues encountered by NPS groundwater vulnerability assessment, as discussed by Stewart [2001], are the large spatial scales, the complex processes that govern fluid flow and solute transport in the unsaturated zone, the absence of unsaturated zone measurements of diffuse pesticide concentrations in 3-D regional-scale space as these are difficult, time consuming, and prohibitively costly, and the computational effort required for solving the nonlinear equations for physically-based modeling of regional scale, heterogeneous applications. As an alternative solution, here is presented an approach that is based on coupling of transfer function and GIS modeling that: a) is capable of solute concentration estimation at a depth of interest within a known error confidence class; b) uses available soil survey, climatic, and irrigation information, and requires minimal computational cost for application; c) can dynamically support decision making through thematic mapping and 3D scenarios This result was pursued through 1) the design and building of a spatial database containing environmental and physical information regarding the study area, 2) the development of the transfer function procedure for layered soils, 3) the final representation of results through digital mapping and 3D visualization. One side GIS modeled environmental data in order to characterize, at regional scale, soil profile texture and depth, land use, climatic data, water table depth, potential evapotranspiration; on the other side such information was implemented in the up-scaling procedure of the Jury's TFM resulting in a set of texture based travel time

  20. Modeling non-point source pollutants in the vadose zone: Back to the basics

    NASA Astrophysics Data System (ADS)

    Corwin, Dennis L.; Letey, John, Jr.; Carrillo, Marcia L. K.

    More than ever before in the history of scientific investigation, modeling is viewed as a fundamental component of the scientific method because of the relatively recent development of the computer. No longer must the scientific investigator be confined to artificially isolated studies of individual processes that can lead to oversimplified and sometimes erroneous conceptions of larger phenomena. Computer models now enable scientists to attack problems related to open systems such as climatic change, and the assessment of environmental impacts, where the whole of the interactive processes are greater than the sum of their isolated components. Environmental assessment involves the determination of change of some constituent over time. This change can be measured in real time or predicted with a model. The advantage of prediction, like preventative medicine, is that it can be used to alter the occurrence of potentially detrimental conditions before they are manifest. The much greater efficiency of preventative, rather than remedial, efforts strongly justifies the need for an ability to accurately model environmental contaminants such as non-point source (NPS) pollutants. However, the environmental modeling advances that have accompanied computer technological development are a mixed blessing. Where once we had a plethora of discordant data without a holistic theory, now the pendulum has swung so that we suffer from a growing stockpile of models of which a significant number have never been confirmed or even attempts made to confirm them. Modeling has become an end in itself rather than a means because of limited research funding, the high cost of field studies, limitations in time and patience, difficulty in cooperative research and pressure to publish papers as quickly as possible. Modeling and experimentation should be ongoing processes that reciprocally enhance one another with sound, comprehensive experiments serving as the building blocks of models and models

  1. ASSESSING NON-POINT SOURCES OF NITROGEN TO SMALL STREAMS IN THE SOUTH FORK BROAD RIVER WATERSHED (GEORGIA, USA)

    EPA Science Inventory

    The National Land Cover Data (NLCD) is a land cover classification derived from Landsat Thematic Mapper satellite data collected in the early to mid-1990s. In this work, land use coverages calculated from the NLCD database are used to assess the impact of non-point sources on the...

  2. Metabolomics for in situ environmental monitoring of surface waters impacted by contaminants from both point and non-point sources

    EPA Science Inventory

    We investigated the efficacy of metabolomics for field-monitoring of fish exposed to waste water treatment plant (WWTP) effluents and non-point sources of chemical contamination. Lab-reared male fathead minnows (Pimephales promelas, FHM) were held in mobile monitoring units and e...

  3. [Source apportionment of nitrogen and phosphorus from cropping non-point source pollution in Nansi Lake basin].

    PubMed

    Liu, Jing; Lu, Feng; Yang, Yan-Zhao; Xu, Na; Wang, Tian-Ni

    2012-09-01

    Field runoff pools were used to collect the field surface runoff samples of different cropping systems in Nansi Lake region, and different forms of nitrogen (N) and phosphorus (P) data were analyzed. The source profiles of N and P in different cropping systems were also obtained by summarizing the experimental data measured in the current study. Samples were also collected from the 11 main rivers of Nansi Lake basin and the concentrations of N and P were determined. Principle component analysis (PCA) was applied to obtain cropping non-point pollution sources of N and P. The result showed that three types of N and P contamination sources were apportioned in Nansi Lake basin, explaining 95.275% of the total variance. The first source was from field surface runoff of wheat-maize rotation with a wide pollution range and a larger contribution, and it contributed 50. 220% of the total contamination burden; the second type of N and P source was the water runoff pollution from garlic-maize rotation, were 25.119% contribution; the third source was the surface runoff from wheat-rice rotation, and it contributed 19.937%.

  4. [Spatial discharge characteristics and total load control of non-point source pollutants based on the catchment scale].

    PubMed

    Wang, Xia-Hui; Lu, Jun; Zhang, Qing-Zhong; Wang, Bo; Yao, Rui-Hua; Zhang, Hui-Yuan; Huang, Feng

    2011-09-01

    Agricultural non-point source pollution is one of the major causes of water quality deterioration. Based on the analysis of the spatial discharge characteristics and intensity of major pollutants from the agricultural pollution source, the establishment of spatial management subzones for controlling agricultural non-point pollution and a design of a plan for total load control of pollutants from each subzone is an important way to improve the efficiency of control measures. In this paper the Four Lake basin in Hubei Province is adopted as the research case region and a systematic research of the control countermeasures of agricultural non-point pollution based on the catchment scale is carried out. The results shows that in the Four Lake basin, the COD, total nitrogen, total phosphorus and ammonia nitrogen load of the water environment are mainly caused by agricultural non-point pollution. These four kinds of non-point source pollutants respectively account for 67.6%, 82.2%, 84.7% and 50.9% of the total pollutant discharge amount in the basin. The analysis of the spatial discharge characteristics of non-point source pollutants in the Four Lake basin shows that the major contributor source regions of non-point source pollutant in the basin are the four counties, including Honghu, Jianli, Qianjiang and Shayang where the aquatic and livestock production are relatively developed. According to the spatial discharge characteristics of the pollutants and the evaluation of the discharge intensity of pollutants, the Four Lake basin is divided into three agricultural non-point pollution management subzones, which including Changhu upstream aquatic and livestock production pollution control subzone, Four-lake trunk canal rural non-point source pollution control subzone and Honghu aquatic production pollution control subzone. Specific pollution control measures are put forward for each subzone. With a comprehensive consideration of the water quality amelioration and the

  5. Impacts of DEM uncertainties on critical source areas identification for non-point source pollution control based on SWAT model

    NASA Astrophysics Data System (ADS)

    Xu, Fei; Dong, Guangxia; Wang, Qingrui; Liu, Lumeng; Yu, Wenwen; Men, Cong; Liu, Ruimin

    2016-09-01

    The impacts of different digital elevation model (DEM) resolutions, sources and resampling techniques on nutrient simulations using the Soil and Water Assessment Tool (SWAT) model have not been well studied. The objective of this study was to evaluate the sensitivities of DEM resolutions (from 30 m to 1000 m), sources (ASTER GDEM2, SRTM and Topo-DEM) and resampling techniques (nearest neighbor, bilinear interpolation, cubic convolution and majority) to identification of non-point source (NPS) critical source area (CSA) based on nutrient loads using the SWAT model. The Xiangxi River, one of the main tributaries of Three Gorges Reservoir in China, was selected as the study area. The following findings were obtained: (1) Elevation and slope extracted from the DEMs were more sensitive to DEM resolution changes. Compared with the results of the 30 m DEM, 1000 m DEM underestimated the elevation and slope by 104 m and 41.57°, respectively; (2) The numbers of subwatersheds and hydrologic response units (HRUs) were considerably influenced by DEM resolutions, but the total nitrogen (TN) and total phosphorus (TP) loads of each subwatershed showed higher correlations with different DEM sources; (3) DEM resolutions and sources had larger effects on CSAs identifications, while TN and TP CSAs showed different response to DEM uncertainties. TN CSAs were more sensitive to resolution changes, exhibiting six distribution patterns at all DEM resolutions. TP CSAs were sensitive to source and resampling technique changes, exhibiting three distribution patterns for DEM sources and two distribution patterns for DEM resampling techniques. DEM resolutions and sources are the two most sensitive SWAT model DEM parameters that must be considered when nutrient CSAs are identified.

  6. [Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

    PubMed

    Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

    2015-07-01

    Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff.

  7. [Risk assessment and safety evaluation using system normative indexes integration method for non-point source pollution on watershed scale].

    PubMed

    Liu, Jian-Chang; Yan, Yan; Liu, Feng; Ding, Ding; Zhao, Ming

    2008-03-01

    Decision-makers take non-point source pollution under control as well as possible results from enough information of risk trend of nonpoint source pollution on watershed scale. System normative indexes integration evaluation method about system risk trend was developed when focusing on that the probability values of some elements attributing to some trend of the system were more than one, and that the system evaluation needed a formula from the system structure. On the basis of analysis on aspects and characteristics of the system risk normalization, a new valuation method, the relationship between the normalization values of the system and the factors was established. The Lugu Lake Watershed in Southwest China was selected as study area to assess the risk of non-point source loss to surface water using this method. The results indicate that 1) the wholly risk of non-point source loss to surface water in this watershed is in a high level; 2) the system indexes integration evaluation method is an universal method to evaluate a quality or a trend of any system and shows a great power in comparing several systems; 3) the method is helpful to attain an effective and integrated assessment on a system when it is combined with other methods.

  8. Identifying non-point source critical source areas based on multi-factors at a basin scale with SWAT

    NASA Astrophysics Data System (ADS)

    Liu, Ruimin; Xu, Fei; Zhang, Peipei; Yu, Wenwen; Men, Cong

    2016-02-01

    The identification of critical source areas (CSAs) is a precondition for non-point source (NPS) pollution control at a basin scale, especially in areas with limited resources. Based on the Soil and Water Assessment Tool (SWAT), nutrient loads coupled with population density and water quality requirements are regarded as multi-factors for CSAs identification in Xiangxi river watershed, the first tributary of the Yangtze River. The results based on the calibrated model found that the subbasins heavily and seriously polluted by nutrient loads were different from the subbasins identified as CSAs, demonstrating integrating socio-economic factors like population density and water quality requirements to identify CSAs is of much necessity. The CSAs occupied 19.7% of the total subbasins, and accounted for 53% total nitrogen loads, 54% total phosphorus loads and 36% of the total population. Considering the model calibration and validation will take a long time as well as data deficiency in some subbasins, the influence of uncalibrated SWAT on CSAs identifications was discussed. The comparative results between CSAs identification with calibrated and uncalibrated SWAT model revealed that model calibration had little effect on nutrients distribution and CSAs locations in the study area. Uncalibrated SWAT model may be applied when the research objective is less related to model calibration. The results will be greatly effective for CSAs identification and NPS pollution control at a basin scale.

  9. [Establishment and application of the estimation model for agricultural non-point source pollution in the field].

    PubMed

    Li, Qiang-kun; Li, Huai-en; Hu, Ya-wei; Chen, Wei-wei; Sun, Juan

    2009-12-01

    The quantitative research on pollution loads is the basis of control, evaluation and management of non-point source pollution. The estimation of agricultural non-point source pollution loads includes two steps: evaluation of water discharge and prediction of pollutant concentration in agricultural drain. Water discharge was calculated by DRAINMOD model based on the principle of water balance on farmland. Meanwhile, the synthesis of fertilization and irrigation is used as an impulse input to the farmland, the pollutant concentration changes in agricultural drain is looked as the response process corresponding to the impulse input, the complex migratory and transforming process of pollutant in soil are expressed implied by Inverse Gaussian Probability Density Function. Based on the above, the estimation model of agricultural non-point source pollution loads at field scale was constructed. Taking the typical experimentation area of Qingtongxia Irrigation District in Ningxia as an example, the loads of nitrate nitrogen and total phosphorus in paddy-field drain was simulated by this model. The results show that the simulated accorded with measured data approximately and Nash-Suttcliffe coefficient is 0.963 and 0.945 respectively.

  10. Anthropogenic point-source and non-point-source nitrogen inputs into Huai River basin and their impacts on riverine ammonia-nitrogen flux

    NASA Astrophysics Data System (ADS)

    Zhang, W. S.; Swaney, D. P.; Li, X. Y.; Hong, B.; Howarth, R. W.; Ding, S. H.

    2015-07-01

    This study provides a new approach to estimate both anthropogenic non-point-source and point-source nitrogen (N) inputs to the landscape, and determines their impacts on riverine ammonia-nitrogen (AN) flux, providing a foundation for further exploration of anthropogenic effects on N pollution. Our study site is Huai River basin of China, a water-shed with one of the highest levels of N input in the world. Multi-year average (2003-2010) inputs of N to the watershed are 27 200 ± 1100 kg N km-2 yr-1. Non-point sources comprised about 98 % of total N input, and only 2 % of inputs are directly added to the aquatic ecosystem as point sources. Fertilizer application was the largest non-point source of new N to the Huai River basin (69 % of net anthropogenic N inputs), followed by atmospheric deposition (20 %), N fixation in croplands (7 %), and N content of imported food and feed (2 %). High N inputs showed impacts on riverine AN flux: fertilizer application, point-source N input, and atmospheric N deposition were proved as more direct sources to riverine AN flux. Modes of N delivery and losses associated with biological denitrification in rivers, water consumption, interception by dams may influence the extent of export of riverine AN flux from N sources. Our findings highlight the importance of anthropogenic N inputs from both point sources and non-point sources in heavily polluted watersheds, and provide some implications for AN prediction and management.

  11. [Present status, mechanisms, and control techniques of nitrogen and phosphorus non-point source pollution from vegetable fields].

    PubMed

    Huang, Dong-Feng; Wang, Guo; Li, Wei-Hua; Qiu, Xiao-Xuan

    2009-04-01

    Chemical fertilizers are often excessively applied on vegetable fields to pursue higher yields. In some areas, the fertilization rates are several times of those needed by vegetables. Nitrogen and phosphorous are obviously accumulated in the vegetable soils, resulting in the malnutrition, excessive nitrate, and poor quality of vegetables. Furthermore, a series of environmental problems, e.g., deterioration of vegetable soil physical and chemical properties, nitrate pollution of groundwater, and eutrophication of surface water, are produced. This paper reviewed the present status of nitrogen and phosphorous non-point source pollution from vegetable soils (accumulation characteristics of nitrogen and phosphorous and their pollution risks to water environment and vegetables), pollution mechanisms (sources, transformation, and losses of nitrogen and phosphorous), and control techniques (fertilization, chemical addition, nitrogen catch crop cultivation, optimal planting system, spatial matching of source and sink landscapes, and grass buffer strip technology), aimed to supply references for the further study on the nitrogen and phosphorous non-point source pollution from vegetable fields.

  12. Soil erosion and non-point source pollution impacts assessment with the aid of multi-temporal remote sensing images.

    PubMed

    Ning, Shu-Kuang; Chang, Ni-Bin; Jeng, Kai-Yu; Tseng, Yi-Hsing

    2006-04-01

    Soil erosion associated with non-point source pollution is viewed as a process of land degradation in many terrestrial environments. Careful monitoring and assessment of land use variations with different temporal and spatial scales would reveal a fluctuating interface, punctuated by changes in rainfall and runoff, movement of people, perturbation from environmental disasters, and shifts in agricultural activities and cropping patterns. The use of multi-temporal remote sensing images in support of environmental modeling analysis in a geographic information system (GIS) environment leading to identification of a variety of long-term interactions between land, resources, and the built environment has been a highly promising approach in recent years. This paper started with a series of supervised land use classifications, using SPOT satellite imagery as a means, in the Kao-Ping River Basin, South Taiwan. Then, it was designed to differentiate the variations of eight land use patterns in the past decade, including orchard, farmland, sugarcane field, forest, grassland, barren, community, and water body. Final accuracy was confirmed based on interpretation of available aerial photographs and global positioning system (GPS) measurements. Finally, a numerical simulation model (General Watershed Loading Function, GWLF) was used to relate soil erosion to non-point source pollution impacts in the coupled land and river water systems. Research findings indicate that while the decadal increase in orchards poses a significant threat to water quality, the continual decrease in forested land exhibits a potential impact on water quality management. Non-point source pollution, contributing to part of the downstream water quality deterioration of the Kao-Ping River system in the last decade, has resulted in an irreversible impact on land integrity from a long-term perspective.

  13. [Estimation of urban non-point source pollution loading and its factor analysis in the Pearl River Delta].

    PubMed

    Liao, Yi-Shan; Zhuo, Mu-Ning; Li, Ding-Qiang; Guo, Tai-Long

    2013-08-01

    In the Pearl Delta region, urban rivers have been seriously polluted, and the input of non-point source pollution materials, such as chemical oxygen demand (COD), into rivers cannot be neglected. During 2009-2010, the water qualities at eight different catchments in the Fenjiang River of Foshan city were monitored, and the COD loads for eight rivulet sewages were calculated in respect of different rainfall conditions. Interesting results were concluded in our paper. The rainfall and landuse type played important roles in the COD loading, with greater influence of rainfall than landuse type. Consequently, a COD loading formula was constructed that was defined as a function of runoff and landuse type that were derived SCS model and land use map. Loading of COD could be evaluated and predicted with the constructed formula. The mean simulation accuracy for single rainfall event was 75.51%. Long-term simulation accuracy was better than that of single rainfall. In 2009, the estimated COD loading and its loading intensity were 8 053 t and 339 kg x (hm2 x a)(-1), and the industrial land was regarded as the main source of COD pollution area. The severe non-point source pollution such as COD in Fenjiang River must be paid more attention in the future.

  14. Relative importance of wastewater treatment plants and non-point sources of perfluorinated compounds to Washington State rivers.

    PubMed

    Furl, Chad V; Meredith, Callie A; Strynar, Mark J; Nakayama, Shoji F

    2011-07-01

    Perfluorinated compounds (PFCs) were measured in 10 Washington State rivers and 4 wastewater treatment plants (WWTPs) under periods of low and high flows to investigate the relative importance of point and non-point sources to rivers. PFCs were detected in all samples with summed values ranging from 1.11 to 74.9 ng/L in surface waters and 62.3-418 ng/L in WWTP effluent. Concentrations in 6 of the 10 rivers exhibited a positive relationship with flow, indicating runoff as a contributing source, with PFC loads greatest at all 10 waterbodies during high flows. Perfluoroheptanoic acid:perfluorooctanoic acid homologue ratios suggest atmospheric contributions to the waterbodies are important throughout the year. Principal component analysis (PCA) indicated distinct homologue profiles for high flow, low flow, and effluent samples. The PCA demonstrates that during the spring when flows and loads are at their greatest; WWTP discharges are not the primary sources of PFCs to the river systems. Taken together, the evidence provided signifies non-point inputs are a major pathway for PFCs to surface waters in Washington State.

  15. Preliminary study on using rare earth elements to trace non-point source phosphorous loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The environmental fate of phosphorus (P) is of concern as P is a primary cause of freshwater eutrophication. Rare earth elements (REEs) have been successfully used in the analysis of soil erosion and pollutant sources, as well as in the analysis of mineral genesis. To better understand the potential...

  16. A Spatial and Temporal Assessment of Non-Point Groundwater Pollution Sources, Tutuila Island, American Samoa

    NASA Astrophysics Data System (ADS)

    Shuler, C. K.; El-Kadi, A. I.; Dulaiova, H.; Glenn, C. R.; Fackrell, J.

    2015-12-01

    The quality of municipal groundwater supplies on Tutuila, the main island in American Samoa, is currently in question. A high vulnerability for contamination from surface activities has been recognized, and there exists a strong need to clearly identify anthropogenic sources of pollution and quantify their influence on the aquifer. This study examines spatial relationships and time series measurements of nutrients and other tracers to identify predominant pollution sources and determine the water quality impacts of the island's diverse land uses. Elevated groundwater nitrate concentrations are correlated with areas of human development, however, the mixture of residential and agricultural land use in this unique village based agrarian setting makes specific source identification difficult using traditional geospatial analysis. Spatial variation in anthropogenic impact was assessed by linking NO3- concentrations and δ15N(NO3) from an extensive groundwater survey to land-use types within well capture zones and groundwater flow-paths developed with MODFLOW, a numerical groundwater model. Land use types were obtained from high-resolution GIS data and compared to water quality results with multiple-regression analysis to quantify the impact that different land uses have on water quality. In addition, historical water quality data and new analyses of δD and δ18O in precipitation, groundwater, and mountain-front recharge waters were used to constrain the sources and mechanisms of contamination. Our analyses indicate that groundwater nutrient levels on Tutuila are controlled primarily by residential, not agricultural activity. Also a lack of temporal variation suggests that episodic pollution events are limited to individual water sources as opposed to the entire aquifer. These results are not only valuable for water quality management on Tutuila, but also provide insight into the sustainability of groundwater supplies on other islands with similar hydrogeology and land

  17. Study of landscape patterns of variation and optimization based on non-point source pollution control in an estuary.

    PubMed

    Jiang, Mengzhen; Chen, Haiying; Chen, Qinghui; Wu, Haiyan

    2014-10-15

    Appropriate increases in the "sink" of a landscape can reduce the risk of non-point source pollution (NPSP) to the sea at relatively lower costs and at a higher efficiency. Based on high-resolution remote sensing image data taken between 2003 and 2008, we analyzed the "source" and "sink" landscape pattern variations of nitrogen and phosphorus pollutants in the Jiulongjiang estuary region. The contribution to the sea and distribution of each pollutant in the region was calculated using the LCI and mGLCI models. The results indicated that an increased amount of pollutants was contributed to the sea, and the "source" area of the nitrogen NPSP in the study area increased by 32.75 km(2). We also propose a landscape pattern optimization to reduce pollution in the Jiulongjiang estuary in 2008 through the conversion of cultivated land with slopes greater than 15° and paddy fields near rivers, and an increase in mangrove areas.

  18. Stochastic Analysis of Non Point Source Loading of Fecal Bacteria in a Shallow Heterogeneous Aquifer

    NASA Astrophysics Data System (ADS)

    Cook, S. J.; Li, X.; Atwill, R.; Packman, A. I.; Harter, T.

    2011-12-01

    Manure and wastewater irrigation (MWI) presents a microbiological risk to shallow groundwater quality. Particularly vulnerable are domestic wells in rural areas where treatment systems may be limited or unreliable. However, despite multiple and persistent sources of fecal contamination, cross sectional monitoring of fecal bacteria in groundwater indicates a high degree of variability in both prevalence and measured concentrations. Apparently random variation occurs both between wells and samples at individual wells. In contrast, deliberate longitudinal studies of MWIs, particularly in the laboratory, tend to exhibit relatively smooth breakthrough curves consistent with colloid filtration theory. To better characterize potential sources of variability in observed field data, a 3D stochastic groundwater modeling approach representative of irrigation applications to vulnerable alluvial aquifers was developed. Heterogeniety is assessed by incorporating multiple loading functions and hydrostratigraphic representations of a heterogeneous alluvial aquifer. Simulations indicate that irrigation water breakthroughs to wells are generally limited to shallow depths, suggesting limited risk to domestic wells screened several tens of meters below the water table. Whilst the presence of aquifer heterogeneity significantly extends the transport distance and tailing of breakthrough curves, owing to macro-dispersion and in-well mixing, simulated breakthrough curves are relatively smooth and consistent with observed longitudinal studies. This suggests that the highly erratic and variable nature of microorganism detection may be due to highly transient processes, including but not limited to spatio-temporal variations in source variability and limitations in infrequent monitoring programs to properly determine variability.

  19. A multiobjective model for non-point source pollution control for an off-stream reservoir catchment.

    PubMed

    Kao, J J; Chen, W J

    2003-01-01

    Phosphorus loads from agricultural non-point source pollution (NPSP) significantly degrade reservoir water quality, making adequate control of agricultural NPSP necessary for improving the water quality. Controlling NPSP is generally accomplished using various Best Management Practices (BMPs). The present study applies the Agricultural Non-Point Source Pollution (AGNPS) model to simulate NPSP loading and BMP efficiencies and establishes an enhanced multiobjective mixed-integer programming model for NPSP control strategy analyses based on these results. Cost, phosphorus load, sediment load and equity are the four major objectives considered. A case study for the Posan reservoir is presented. Four commonly proposed and applicable BMPs are chosen. Non-inferior solutions obtained using the constraint method and trade-off relationships among different control objectives are described and discussed. Compared with a previously proposed fertilizer control model, results show that the model established herein is more cost-effective and achieves better phosphorus and sediment loading reduction and equity goals. Furthermore, the current model is expected to facilitate decision-making analysis for development of an appropriate cost-sharing program to encourage adoption of appropriate BMPs by farmers.

  20. Evaluation and management of non-point source pollutants in the Lake Tahoe watershed

    SciTech Connect

    Lee, G.F.; Jones-Lee, A.

    1994-12-31

    Lake Tahoe, California-Nevada, one of the most oligotrophic lakes in the world, is experiencing decreased water clarity and increased periphyton growth, and water supplies drawing from the lake are experiencing increased algal-related tastes and odors. The growth of algae in Lake Tahoe is primarily limited by the nitrogen (nitrate and ammonia) loads to the lake, which have been increasing over the years. The nitrogen that is causing the increased fertilization of the lake is primarily derived from atmospheric sources through precipitation onto the lake`s surface. A potentially highly significant source of atmospheric nitrogen in the Lake Tahoe Basin is automobile, bus, and truck engine exhaust discharge of NOx. The fertilization of lawns and other shrubbery, including golf courses, within the Lake Tahoe Basin is also leading to significant growths of attached algae in the nearshore waters of the lake. The fertilizers are transported via groundwater to the nearshore areas of the lake. In order to prevent further deterioration of Lake Tahoe`s eutrophication-related water quality, there is immediate need to control atmospheric input of nitrate and ammonia to the lake`s surface, and to control use of fertilizers on lawns, shrubbery, and golf courses in the watershed. The states of California and Nevada, and the Tahoe Regional Planning Authority need to focus considerable attention on the determination of whether restricting NOx emissions from vehicular traffic within the basin would have a significant beneficial impact on Lake Tahoe`s water clarity.

  1. User's Guide for the Agricultural Non-Point Source (AGNPS) Pollution Model Data Generator

    USGS Publications Warehouse

    Finn, Michael P.; Scheidt, Douglas J.; Jaromack, Gregory M.

    2003-01-01

    BACKGROUND Throughout this user guide, we refer to datasets that we used in conjunction with developing of this software for supporting cartographic research and producing the datasets to conduct research. However, this software can be used with these datasets or with more 'generic' versions of data of the appropriate type. For example, throughout the guide, we refer to national land cover data (NLCD) and digital elevation model (DEM) data from the U.S. Geological Survey (USGS) at a 30-m resolution, but any digital terrain model or land cover data at any appropriate resolution will produce results. Another key point to keep in mind is to use a consistent data resolution for all the datasets per model run. The U.S. Department of Agriculture (USDA) developed the Agricultural Nonpoint Source (AGNPS) pollution model of watershed hydrology in response to the complex problem of managing nonpoint sources of pollution. AGNPS simulates the behavior of runoff, sediment, and nutrient transport from watersheds that have agriculture as their prime use. The model operates on a cell basis and is a distributed parameter, event-based model. The model requires 22 input parameters. Output parameters are grouped primarily by hydrology, sediment, and chemical output (Young and others, 1995.) Elevation, land cover, and soil are the base data from which to extract the 22 input parameters required by the AGNPS. For automatic parameter extraction, follow the general process described in this guide of extraction from the geospatial data through the AGNPS Data Generator to generate input parameters required by the pollution model (Finn and others, 2002.)

  2. Modelling of point and non-point source pollution of nitrate with SWAT in the river Dill, Germany

    NASA Astrophysics Data System (ADS)

    Pohlert, T.; Huisman, J. A.; Breuer, L.; Frede, H.-G.

    2005-12-01

    We used the Soil and Water Assessment Tool (SWAT) to simulate point and non-point source pollution of nitrate in a mesoscale mountainous catchment. The results show that the model efficiency for daily discharge is 0.81 for the calibration period (November 1990 to December 1993) and 0.56 for the validation period (April 2000 to January 2003). The model efficiency for monthly nitrate load is 0.66 and 0.77 for the calibration period (April 2000 to March 2002) and validation period (April 2002 to January 2003), respectively. However, the model efficiency for daily loads is low (0.15), which cannot only be attributed to the quality of input data of point source effluents. An analysis of the internal fluxes and cycles of nitrogen pointed out considerable weaknesses in the models conceptualisation of the nitrogen modules which will be improved in future research.

  3. Search for the northwest passage: the assignation of NSP (non-point source pollution) rights in nutrient trading programs.

    PubMed

    Collentine, D

    2002-01-01

    The search for solutions to the problem of non-point source pollution (NSP) includes alternatives based on theories associated with the use of tradable pollution permits. Tradable permit programs have received significant support as a promising policy for the reduction of effluent discharges but programs in practice have not been regarded as successful. The lack of success is ascribed to the design of the programs. However, this may be a design problem which is insurmountable due to the nature of the NSP problem. Tradable permit solutions are based on an assumption that the assignation of quantifiable rights to both point and nonpoint sources, based on some predetermined ambient water quality measure, is possible. The conclusion here is that there are significant features particular to NSP that hinder the introduction of rights and significantly decrease the utility of tradable permit solutions.

  4. Evaluating potential non-point source loading of PAHs from contaminated soils: a fugacity-based modeling approach.

    PubMed

    Luo, Xiaolin; Zheng, Yi; Lin, Zhongrong; Wu, Bin; Han, Feng; Tian, Yong; Zhang, Wei; Wang, Xuejun

    2015-01-01

    Soils contaminated by Polycyclic Aromatic Hydrocarbons (PAHs) are subject to significant non-point source (NPS) pollution during rainfall events. Recent studies revealed that the classic enrichment ratio (ER) approach may not be applicable to PAHs. This study developed a model to estimate the ER of PAHs which innovatively applies the fugacity concept. The ER model has been validated with experimental data, which suggested that the transport of PAHs not only depends on their physicochemical properties, but on the sediment composition and how the composition evolves during the event. The modeling uncertainty was systematically examined, and found to be highly compound-dependent. Based on the ER model, a strategy was proposed to practically evaluate the potential NPS loading of PAHs in watersheds with heterogeneous soils. The study results have important implications to modeling and managing the NPS pollution of PAHs (or other chemicals alike) at a watershed scale.

  5. Validation and future predictions based on a new Non-Point Source Assessment Toolbox, applied to the Central Valley, California

    NASA Astrophysics Data System (ADS)

    Kourakos, G.; Harter, T.

    2011-12-01

    Groundwater is a major irrigation water source in semi-arid regions. It is also vulnerable to Non-Point Source (NPS) contamination, particularly from nitrate (NO3-) as a result of agricultural practices. To support sound policy decisions we developed a physically based flow and transport model framework to understand and predict the fate of contaminants within regional aquifer systems. In large aquifers, the total source area of pollutants typically cover several thousand square kilometers, whilst individual sources typically do not exceed a few hundred square meters. The large contrast in these scenarios result in NPS modeling tasks that are computationally demanding, and the classical 3D models that solve the Advection-Dispersion Equation (ADE) are often not applicable due to computer memory limitations, numerical dispersion and numerical instabilities. Here, we developed and employed a number of numerical techniques to assemble a Non-Point Source Assessment Toolbox (NPSAT). The NPSAT is a quasi-3D model, combining a flow model and a streamline transport model. The flow model solves the groundwater flow equation using very fine discretization. For very large groundwater basins, a simplistic decomposition method is applied, splitting the aquifer into several overlapping sub-domains and solving to produce a high resolution velocity field. This velocity field is subsequently utilized within the transport model, where backward particle tracking links contamination sources with discharge surfaces using a large number of streamlines. For each streamline the 1D ADE is solved, assuming a unit pulse loading at the source side and a free exit boundary condition at the discharge surface side. From this, a Unit Response Function (URF) is obtained at the discharge surface side. Subsequently, actual Breakthrough Curves (BTCs) can be quickly computed from actual or hypothetical loading histories, by convoluting the URFs with real loading functions. The URFs are stored into a

  6. An Experimental Study on Using Rare Earth Elements to Trace Non-point source Phosphorous LossA

    NASA Astrophysics Data System (ADS)

    Liang, T.

    2011-12-01

    Controlling phosphorous (P) inputs through management of its sources and transport is critical for limiting freshwater eutrophication. Rare earth elements (REEs) have been successfully used in the analysis of soil erosion and pollutant sources, as well as in the analysis of mineral genesis. To better understand the potential for REE use in tracing non-point sources of P, we examined the combined fate of REEs and P in Chinese soils amended with REEs and documented the formation of REE-P compounds. Laboratory leaching experiments and artificial simulated rainfall experiments were conducted. Vertical leaching transfers of REEs and P were relatively small, with transport depths less than 6 cm for most REEs and P. Export of applied REEs in leachate accounted for less that 5% of inputs. The vertical mobility order of REEs and P in Chinese soils was greatest for purple soil, followed by terra nera soil, then red soil, followed by cinnamon soil, and finally loess soil. Losses of rare earth elements and P in surface runoff exhibited a parabolic relationship to simulated rainfall intensity. With greater exogenous La application, the amount of water soluble P, bicarbonate-extractable P and hydroxide-extractable P decreased significantly, while acid-extractable and residual forms of P increased significantly. In addition, characteristics of exogenous rare earth elements (REEs) and P and their losses with surface runoff (both in the water and sediments) during simulated rainfall experiments (83 mm h-1) were investigated. The results revealed that most REEs (La, 94%; Nd, 93%; Sm, 96%) and P (96%) transported with sediments in the runoff. The total amounts of losses of REEs and P in the runoff were significantly correlated, suggesting the possibility of using REEs to trace the fate of agricultural nonpoint P losses.

  7. Simulation of spatial and temporal distributions of non-point source pollution load in the Three Gorges Reservoir Region.

    PubMed

    Shen, Zhenyao; Qiu, Jiali; Hong, Qian; Chen, Lei

    2014-09-15

    Non-point source (NPS) pollution has become the largest threat to water quality in recent years. Major pollutants, particularly from agricultural activities, which include nitrogen, phosphorus and sediment that have been released into aquatic environments, have caused a range of problems in the Three Gorges Reservoir Region (TGRR), China. It is necessary to identify the spatial and temporal distributions of NPS pollutants and the highly polluted areas for the purpose of watershed management. In this study, the NPS pollutant load was simulated using the Soil and Water Assessment Tool (SWAT) and the small-scale watershed extended method (SWEM). The simulation results for four typical small catchments were extended to the entire watershed leading to estimates of the NPS load from 2001 to 2009. The results demonstrated that the NPS pollution load in the western area was the highest and that agricultural land was the primary pollutant source. The similar annual variation trends of runoff and sediment loads demonstrated that the sediment load was closely related to runoff. The loads of total nitrogen (TN) and total phosphorus (TP) were relatively stable from 2001 to 2007, except for high loads in 2006. The increase in pollution source strength was an important reason for the significant upward trend of TN and TP loads from 2008 to 2009. The rainfall from April to October contributed to the largest amount of runoff, sediment and nutrient loads for the year. The NPS load intensities in each sub-basin reveal large variations in the spatial distribution of different pollutants. It was shown that the temporal and spatial distributions of pollutant loads were positively correlated with the annual rainfall amounts and with human activities. Furthermore, this finding illustrates that conservation practices and nutrient management should be implemented in specific sites during special periods for the purpose of NPS pollution control in the TGRR.

  8. Influencing factor analysis of phosphorus loads from non-point source: a case study in central China.

    PubMed

    Zhuang, Yanhua; Hong, Song; Zhan, F Benjamin; Zhang, Liang

    2015-11-01

    The influence factor analysis for non-point source (NPS) pollution is very important to taking effective water pollution control measures. In this study, the self-organizing map (SOM) and linear model analysis were used to analyze the relationships between total phosphorus (TP) loads and influencing factors, both qualitatively and quantitatively. The land-use type, topography, and vegetation coverage were the main factors influencing the export of TP loads in Tangxun watershed. Slope and normalized difference vegetation index (NDVI) were chosen as characteristic indices of topography and vegetation coverage, respectively. For the whole watershed, the high TP loads were mainly distributed in areas with high slope and low vegetation coverage for a specific land-use type. For different land types, the slope significantly influenced the export of TP loads in waste/bare land and forest/green land while NDVI influenced the export of TP loads in forest/green land and farmland. In terms of multi-factor analysis, the comprehensive influence of slope and NDVI on TP loads showed as waste/bare land>forest/green land>farmland>rural/urban construction land.

  9. Assessment of the relationship between rural non-point source pollution and economic development in the Three Gorges Reservoir Area.

    PubMed

    Zhang, Tong; Ni, Jiupai; Xie, Deti

    2016-04-01

    This study investigates the relationship between rural non-point source (NPS) pollution and economic development in the Three Gorges Reservoir Area (TGRA) by using the Environmental Kuznets Curve (EKC) hypothesis for the first time. Five types of pollution indicators, namely, fertilizer input density (FD), pesticide input density (PD), agricultural film input density (AD), grain residues impact (GI), and livestock manure impact (MI), were selected as rural NPS pollutant variables. Rural net income per capita was used as the indicator of economic development. Pollution load was generated by agricultural inputs (consumption of fertilizer, pesticide, and agricultural film) and economic growth with invert U-shaped features. The predicted turning points for FD, PD, and AD were at rural net income per capita levels of 6167.64, 6205.02, and 4955.29 CNY, respectively, which were all surpassed. However, the features between agricultural waste outputs (grain residues and livestock manure) and economic growth were inconsistent with the EKC hypothesis, which reflected the current trends of agricultural economic structure in the TGRA. Given that several other factors aside from economic development level could influence the pollutant generation in rural NPS, a further examination with long-run data support should be performed to understand the relationship between rural NPS pollution and income level.

  10. Non-point source mercury emission from the Idrija Hg-mine region: GIS mercury emission model.

    PubMed

    Kocman, David; Horvat, Milena

    2011-08-01

    A mercury emission model was developed to estimate non-point source mercury (Hg) emissions occurring over the year from the Idrijca River catchment, draining the area of the world's second largest Hg mine in Idrija, Slovenia. Site-specific empirical correlations between the measured Hg emission fluxes and the parameters controlling the emission (comprising substrate Hg content, soil temperature, solar radiation and soil moisture) were incorporated into the mercury emission model developed using Geographic Information System technology. In this way, the spatial distribution and significance of the most polluted sites that need to be properly managed was assessed. The modelling results revealed that annually approximately 51 kg of mercury are emitted from contaminated surfaces in the catchment (640 km(2)), highlighting that emission from contaminated surfaces contributes significantly to the elevated Hg concentrations in the ambient air of the region. Very variable meteorological conditions in the modelling domain throughout the year resulted in the high seasonal and spatial variations of mercury emission fluxes observed. Moreover, it was found that mercury emission fluxes from surfaces in the Idrija region are 3-4 fold higher than the values commonly used in models representing emissions from global mercuriferous belts. Sensitivity and model uncertainty analysis indicated the importance of knowing not only the amount but also the type of mercury species and their binding in soils in future model development.

  11. [Reduction effects of agricultural management practices on non-point source pollution in a watershed in Three Gorges Reservoir Area].

    PubMed

    Huang, Zhi-Lin; Tian, Yao-Wu; Xiao, Wen-Fa; Liu, Zhi-Yan

    2010-06-01

    Taking a typical watershed in the Three Gorges Reservoir Area (TGRA) as test object, the AnnAGNPS model was used to evaluate the reduction effects of different cropping, different fertilization level, conservation tillage practice (CTP), conservation reserve program (CRP), and conversion of cropland into forestland program (CCFP) on the output of agricultural non-point source pollution (NPS) in the watershed. The simulation results showed that different cropping had no significant difference in the effect of reducing sediment yield, but had significant difference in the effect of reducing phosphorus output. Fertilization level had significant effects on the outputs of total nitrogen and total phosphorus. CTP decreased the sediment yield significantly but increased the nutrient output. CRP reduced sediment yield, but had less effect in reducing nutrient output. CCFP reduced both sediment yield and nutrient output significantly. After the implementation of CCFP, the sediment yield output on the croplands with a slope greater than 10 degrees was less than 5 t x hm(-2) and the nutrient output was within the permissible limit.

  12. Development of an integrated modeling approach for identifying multilevel non-point-source priority management areas at the watershed scale

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Zhong, Yucen; Wei, Guoyuan; Cai, Yanpeng; Shen, Zhenyao

    2014-05-01

    The identification of priority management areas (PMAs) at the large-basin scale is notably complex because of the random nature of watershed processes, which complicates the application of traditional deterministic PMAs. In this study, a multilevel PMA (ML-PMA) framework is designed as a new tool to pinpoint these sensitive areas, within a basin, that contribute the most to water quality deterioration. The main advantage of the ML-PMA framework is the wide availability of its supplementary tools and its complete framework, which integrates both watershed and river processes in addressing PMAs at the watershed scale. The watershed model, stream model, and a Markov chain approach are integrated to depict the dynamics of watershed processes and various water quality statutes. Based on the results of this study, the river migration process is vital for water quality degradation in the river network and significantly influenced the final PMA map. In addition, the proposed ML-PMA framework considers the impact of climatic conditions and hydrological properties and allows for a more cost-effective allocation of PMAs among different years. In the authors' view, the connectivity of PMAs in terms of flux distribution and propagation downstream on which the ML-PMA is based makes the ML-PMA framework particularly interesting for watershed non-point-source pollution control.

  13. Long-term agricultural non-point source pollution loading dynamics and correlation with outlet sediment geochemistry

    NASA Astrophysics Data System (ADS)

    Ouyang, Wei; Jiao, Wei; Li, Xiaoming; Giubilato, Elisa; Critto, Andrea

    2016-09-01

    Some agricultural non-point source (NPS) pollutants accumulate in sediments in the outlet sections of watersheds. It is crucial to evaluate the historical interactions between sediment properties and watershed NPS loading. Therefore, a sediment core from the outlet of an agricultural watershed was collected. The core age was dated using the 210Pb method, and sedimentation rates were determined using the constant rate of supply (CRS) model. The total nitrogen (TN), total phosphorus (TP), Cd, Pb, Cu, Ni and Cr accumulations in the sediment generally showed fluctuating increases, with the highest sedimentation fluxes all occurring in approximately 1998. The measurement of specific mass sedimentation rates reflected a record of watershed soil erosion dynamics. Using SWAT (Soil and Water Assessment Tool) to simulate long-term watershed agricultural NPS pollution loadings, the historical interactions between sediment properties and NPS loadings were further evaluated. The N leaching process weakened these interactions, but the historical accumulations of TP and heavy metals in sediments generally correlated well with watershed NPS TP loading. The regression analysis suggested that Pb and Cr were the most suitable indexes for assessing long-term NPS TN and TP pollution, respectively. Assessing the NPS loading dynamics using the vertical characteristics of sediment geochemistry is a new method.

  14. Non-point source analysis of a railway bridge area using statistical method: case study of a concrete road-bed.

    PubMed

    Gil, Kyungik; Im, Jiyeol

    2014-06-01

    In an effort to protect the quality of the water system, interest in non-point source pollution is increasing. Recently, studies of non-point sources pollution are continuing in relation to various land-use areas, but such studies have not been fully conducted in railway facility sites. Using monitoring data of railway bridge area with concrete road-bed, the runoff characteristics, pollutant unit loads, and first flush criteria were assessed. Railway bridge area with concrete road-bed typically show the first flush effect, and the pollutant unit load was determined to be higher than other public facilities areas. Further, the first flush criteria show an effective rainfall amount of 7 mm. In other words, from the runoff of railway facilities, considerable amounts of non-point source pollutants are occurred, indicating the need to create best management practices which are adequate for railway facility sites.

  15. Mitigation efficacy of vegetated buffers in reducing non-point source pollution: A critical review and meta-analysis

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Liu, X.; Zhang, M.; Dahlgren, R.; Eitzel, M.

    2008-12-01

    Vegetated buffers are the most studied and widely used agricultural management practice for reducing non- point source pollution. A wealth of existing literature provides experimental data on their mitigation efficacy. This paper aggregated many of these results and performed a meta-analysis on them to quantify the relationships between pollutant removal efficacy and buffer width and buffer slope. Theoretical models for removal efficacy (Y) vs. buffer width (w) were derived and tested against data from the surveyed literature using statistical analyses. A model of the form \\Y = K (1 - exp (-bw)) , (0< K ≤100) is shown to successfully capture the relationship between buffer width and pollutant removal, where K reflects the removal capacity of the buffer and b reflects its probability to remove any single particle of pollutant in a unit distance. The estimates of K are 90.9, 93.2, 92.0, and 89.5 for sediment, pesticides, nitrogen (N) and phosphorus (P), respectively. Buffer width alone explains 37, 60, 44 and 35% of the total variance in removal efficacy for sediment, pesticides, N and P. Buffer slope is linearly associated with sediment removal efficacy either positively (when slope ≤9%) or negatively (when slope >9%). A sediment removal model based on buffer width and buffer slope explains 55.8% of the total variation in removal efficacy. Models for all the studied pollutants are statistically significant with P-values <0.001. Based on our analysis, a 30 m buffer removes over 80% of all the studied pollutants. These models predicting optimal buffer width/slope could be instrumental in the implementation and design of vegetated buffers for treating agricultural runoff to meet specific water quality objectives. The quantitative relationship established also provides valuable information for modeling buffer efficacy at the watershed scale.

  16. Assessing the effects of rural livelihood transition on non-point source pollution: a coupled ABM-IECM model.

    PubMed

    Yuan, Chengcheng; Liu, Liming; Ye, Jinwei; Ren, Guoping; Zhuo, Dong; Qi, Xiaoxing

    2017-04-02

    Water pollution caused by anthropogenic activities and driven by changes in rural livelihood strategies in an agricultural system has received increasing attention in recent decades. To simulate the effects of rural household livelihood transition on non-point source (NPS) pollution, a model combining an agent-based model (ABM) and an improved export coefficient model (IECM) was developed. The ABM was adopted to simulate the dynamic process of household livelihood transition, and the IECM was employed to estimate the effects of household livelihood transition on NPS pollution. The coupled model was tested in a small catchment in the Dongting Lake region, China. The simulated results reveal that the transition of household livelihood strategies occurred with the changes in the prices of rice, pig, and labor. Thus, the cropping system, land-use intensity, resident population, and number of pigs changed in the small catchment from 2000 to 2014. As a result of these changes, the total nitrogen load discharged into the river initially increased from 6841.0 kg in 2000 to 8446.3 kg in 2004 and then decreased to 6063.9 kg in 2014. Results also suggest that rural living, livestock, paddy field, and precipitation alternately became the main causes of NPS pollution in the small catchment, and the midstream region of the small catchment was the primary area for NPS pollution from 2000 to 2014. Despite some limitations, the coupled model provides an innovative way to simulate the effects of rural household livelihood transition on NPS pollution with the change of socioeconomic factors, and thereby identify the key factors influencing water pollution to provide valuable suggestions on how agricultural environmental risks can be reduced through the regulation of the behaviors of farming households in the future.

  17. Parameter uncertainty analysis of the non-point source pollution in the Daning River watershed of the Three Gorges Reservoir Region, China.

    PubMed

    Shen, Zhenyao; Hong, Qian; Yu, Hong; Liu, Ruimin

    2008-11-01

    The generation and formation of non-point source pollution involves great uncertainty, and this uncertainty makes monitoring and controlling pollution very difficult. Understanding the main parameters that affect non-point source pollution uncertainty is necessary to provide the basis for the planning and design of control measures. In this study, three methods were adopted to do the parameter uncertainty analysis with the Soil and Water Assessment Tool (SWAT). Based on the results of parameter sensitivity analysis by the Morris screening method, the ten parameters that most affect runoff, sediment, organic N, nitrate, and total phosphorous (TP) were chosen for further uncertainty analysis. First-order error analysis (FOEA) and the Monte Carlo method (MC) were used to analyze the effect of parameter uncertainty on model outputs. FOEA results showed that only a few parameters had significantly affected the uncertainty of the final simulation results, and many parameters had little or no effect. The SCS curve number was the parameter with significant uncertainty impact on runoff, sediment, organic N, nitrate and TP, and it showed that the runoff process was mainly responsible for the uncertainty of non-point source pollution load. The uncertainty of sediment was the biggest among the five model output results described above. MC results indicated that neglecting the parameter uncertainty of the model would underestimate the non-point source pollution load, and that the relationship between model input and output was non-linear. The uncertainty of non-point source pollution exhibited a temporal pattern: It was greater in summer than in winter. The uncertainty of runoff was smaller compared to that of sediment, organic N, nitrate, and TP, and the source of uncertainty was mainly affected by parameters associated with runoff.

  18. Using NASA and Earth Science Products to Improve EPA Non-point Source Water Quality Modeling for the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Toll, D.; Engman, T.; Edward, P.; Magness, A.; Townsend, P.; N-Meister, W.; Nigro, J.; Lee, S.

    2007-12-01

    The Environmental Protection Agency (EPA) estimates that over 20,000 bodies of water throughout the country do not meet water quality standards. Nonpoint sources -- pollution from urban, agricultural, and forest land that is transported by runoff -- typically cause 90 percent of impairments. EPA has developed the BASINS (Better Assessment Science Integrating Point and Nonpoint Sources) modeling system for performing numerous water quality studies. The key to this suite of models is the Hydrological Simulation Program - Fortran (HSPF), which calculates daily stream flow rates and the corresponding pollutant concentrations at the watershed outlet. EPA has partnered with NASA to use high spatial and temporal hydrological variables (e.g., precipitation, evaporation, etc.) from the NASA Land Information System (LIS) and land cover/vegetative indices derived from primarily MODIS and Landsat satellite data non-point source water quality for the Chesapeake Bay Basin. For the precipitation and evaporation data, EPA-based BASINS-HSPF streamflow runs were conducted on seven study watersheds in the Chesapeake Bay Basin. Sets of runs using precipitation from default weather stations, the NASA LIS 1/8th degree precipitation, NOAA Stage IV precipitation, NASA LIS Noah land surface model evapotranspiration datasets were conducted for each watershed. The output statistics summarized reveal that for 74% of the runs, the NASA LIS 1/8th degree and Stage IV precipitation-based runs performed better than when using only the default EPA precipitation station data. In addition, an automatic calibration method ('PEST') and Noah land surface model evapotranspiration (ET) being further incorporated. The empirical ability of generalized spectral indices and land cover derived from Landsat and MODIS was tested for predicting stream water nitrogen export from predominately forested watersheds undergoing disturbance. The disturbance index, a summary index that is easily computed from Landsat

  19. Estimation of contribution from non-point sources to perfluorinated surfactants in a river by using boron as a wastewater tracer.

    PubMed

    Nishikoori, Hiroshi; Murakami, Michio; Sakai, Hiroshi; Oguma, Kumiko; Takada, Hideshige; Takizawa, Satoshi

    2011-08-01

    The contribution of non-point sources to perfluorinated surfactants (PFSs) in a river was evaluated by estimating their fluxes and by using boron (B) as a tracer. The utility of PFSs/B as an indicator for evaluating the impact of non-point sources was demonstrated. River water samples were collected from the Iruma River, upstream of the intake of drinking water treatment plants in Tokyo, during dry weather and wet weather, and 13 PFSs, dissolved organic carbon (DOC), total nitrogen (TN), and B were analyzed. Perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUA), and perfluorododecanoate (PFDoDA) were detected on all sampling dates. The concentrations and fluxes of perfluorocarboxylates (PFCAs, e.g. PFOA and PFNA) were higher during wet weather, but those of perfluoroalkyl sulfonates (PFASs, e.g. PFHxS and PFOS) were not. The wet/dry ratios of PFSs/B (ratios of PFSs/B during wet weather to those during dry weather) agreed well with those of PFS fluxes (ratios of PFS fluxes during wet weather to those during dry weather), indicating that PFSs/B is useful for evaluating the contribution from non-point sources to PFSs in rivers. The wet/dry ratios of PFOA and PFNA were higher than those of other PFSs, DOC, and TN, showing that non-point sources contributed greatly to PFOA and PFNA in the water. This is the first study to use B as a wastewater tracer to estimate the contribution of non-point sources to PFSs in a river.

  20. ModBack - simplified contaminant source zone delineation using backtracking

    NASA Astrophysics Data System (ADS)

    Thielsch, K.; Herold, M.; Ptak, T.

    2012-12-01

    Contaminated groundwater poses a serious threat to drinking water resources all over the world. Even though contaminated water might be detected in observation wells, a proper clean up is often only successful if the source of the contamination is detected and subsequently removed, contained or remediated. The high costs of groundwater remediation could be possibly significantly reduced if, from the outset, a focus is placed on source zone detection. ModBack combines several existing modelling tools in one easy to use GIS-based interface helping to delineate potential contaminant source zones in the subsurface. The software is written in Visual Basic 3.5 and uses the ArcObjects library to implement all required GIS applications. It can run without modification on any Microsoft Windows based PC with sufficient RAM and at least Microsoft .NET Framework 3.5. Using ModBack requires additional installation of the following software: Processing Modflow Pro 7.0, ModPath, CSTREAM (Bayer-Raich et al., 2003), Golden Software Surfer and Microsoft Excel. The graphical user interface of ModBack is separated into four blocks of procedures dealing with: data input, groundwater modelling, backtracking and analyses. Geographical data input includes all georeferenced information pertaining to the study site. Information on subsurface contamination is gathered either by conventional sampling of monitoring wells or by conducting integral pumping tests at control planes with a specific sampling scheme. Hydraulic data from these pumping tests together with all other available information are then used to set up a groundwater flow model of the study site, which provides the flow field for transport simulations within the subsequent contamination backtracking procedures, starting from the defined control planes. The backtracking results are then analysed within ModBack. The potential areas of contamination source presence or absence are determined based on the procedure used by Jarsjö et

  1. EM Sounding Characterization of Soil Environment toward Estimation of Potential Pollutant Load from Non-point Sources

    NASA Astrophysics Data System (ADS)

    Mori, Y.; Ide, J.; Somura, H.; Morisawa, T.

    2010-12-01

    A multi-frequency electro-magnetic (EM) sounding method was applied to agriculture fields to investigate the characteristics of non-point pollution load. Soil environmental properties such as differences in land management were analyzed with electrical conductivity (EC) maps. In addition, vertical EC profiles obtained from EM soundings were compared with EC in drainage ditch or river water. As results, surface soil EC maps successfully extracted the differences in land management affected by fertilizer application. Moreover, surface EC at the vertical profiles strongly related with drainage ditch or river EC, showing most of the EC in the water was explained by surface EC maps at the EM sounding data. The proposed method has strength in obtaining EC data without sampling river water, the situation we sometimes experienced at the field survey.

  2. Simulation of the spatial and temporal changes of complex non-point source loads in a lake watershed of central China.

    PubMed

    Yanhua, Zhuang; Song, Hong; Wenting, Zhang; Hongyan, Lin; Qinghui, Zeng; Thuminh, Nguyen; Beibei, Niu; Wanyi, Li

    2013-01-01

    In this study, a coupling model of agricultural and urban non-point source (AUNPS) is established in order to estimate complex non-point source (NPS) pollutant loads in the urban-rural fringe. Furthermore, a spatial-temporal change model of non-point source (CA-AUNPS) is established by the coupling of AUNPS and cellular automata (CA) models. The total nitrogen (TN) and total phosphorus (TP) loads in Tangxun watershed were simulated during 1991-2020, and the results show that: (1) the CA-AUNPS model is an effective tool to simulate the spatial-temporal changes of NPS pollutant loads in urban-rural fringe; (2) in terms of the spatial changes, the TN and TP loads generally showed as rural/urban construction land > farmland > forest/green land, and the high-value areas of NPS pollutant loads expanded from north to south with the increase of construction land; with regard to temporal changes, the TN and TP loads generally displayed an increasing tendency during 1991-2020, and by 2020 the TN and TP loads will increase to 370.06 and 33.89 t yr(-1), respectively; (3) the spatial-temporal changes of TN and TP loads in Tangxun watershed correlate strongly with the land-use, slope, and rainfall.

  3. The simulation research of dissolved nitrogen and phosphorus non-point source pollution in Xiao-Jiang watershed of Three Gorges Reservoir area.

    PubMed

    Wu, Lei; Long, Tian-Yu; Li, Chong-Ming

    2010-01-01

    Xiao-jiang, with a basin area of almost 5,276 km(2) and a length of 182.4 km, is located in the center of the Three Gorges Reservoir Area, and is the largest tributary of the central section in Three Gorges Reservoir Area, farmland accounts for a large proportion of Xiao-jiang watershed, and the hilly cropland of purple soil is much of the farmland of the watershed. After the second phase of water storage in the Three Gorges Reservoir, the majority of sub-rivers in the reservoir area experienced eutrophication phenomenon frequently, and non-point source (NPS) pollution has become an important source of pollution in Xiao-jiang Watershed. Because dissolved nitrogen and phosphorus non-point source pollution are related to surface runoff and interflow, using climatic, topographic and land cover data from the internet and research institutes, the Semi-Distributed Land-use Runoff Process (SLURP) hydrological model was introduced to simulate the complete hydrological cycle of the Xiao-jiang Watershed. Based on the SLURP distributed hydrological model, non-point source pollution annual output load models of land use and rural residents were respectively established. Therefore, using GIS technology, considering the losses of dissolved nitrogen and phosphorus in the course of transport, a dissolved non-point source pollution load dynamic model was established by the organic coupling of the SLURP hydrological model and land-use output model. Through the above dynamic model, the annual dissolved non-point source nitrogen and phosphorus pollution output as well as the load in different types were simulated and quantitatively estimated from 2001 to 2008, furthermore, the loads of Xiao-jiang Watershed were calculated and expressed by temporal and spatial distribution in the Three Gorges Reservoir Area. The simulation results show that: the temporal changes of dissolved nitrogen and phosphorus load in the watershed are close to the inter-annual changes of rainfall runoff, and the

  4. Multi-angle indicators system of non-point pollution source assessment in rural areas: a case study near Taihu Lake.

    PubMed

    Huang, Lei; Ban, Jie; Han, Yu Ting; Yang, Jie; Bi, Jun

    2013-04-01

    This study aims to identify key environmental risk sources contributing to water eutrophication and to suggest certain risk management strategies for rural areas. The multi-angle indicators included in the risk source assessment system were non-point source pollution, deficient waste treatment, and public awareness of environmental risk, which combined psychometric paradigm methods, the contingent valuation method, and personal interviews to describe the environmental sensitivity of local residents. Total risk values of different villages near Taihu Lake were calculated in the case study, which resulted in a geographic risk map showing which village was the critical risk source of Taihu eutrophication. The increased application of phosphorus (P) and nitrogen (N), loss vulnerability of pollutant, and a lack of environmental risk awareness led to more serious non-point pollution, especially in rural China. Interesting results revealed by the quotient between the scores of objective risk sources and subjective risk sources showed what should be improved for each study village. More environmental investments, control of agricultural activities, and promotion of environmental education are critical considerations for rural environmental management. These findings are helpful for developing targeted and effective risk management strategies in rural areas.

  5. Multi-angle Indicators System of Non-point Pollution Source Assessment in Rural Areas: A Case Study Near Taihu Lake

    NASA Astrophysics Data System (ADS)

    Huang, Lei; Ban, Jie; Han, Yu Ting; Yang, Jie; Bi, Jun

    2013-04-01

    This study aims to identify key environmental risk sources contributing to water eutrophication and to suggest certain risk management strategies for rural areas. The multi-angle indicators included in the risk source assessment system were non-point source pollution, deficient waste treatment, and public awareness of environmental risk, which combined psychometric paradigm methods, the contingent valuation method, and personal interviews to describe the environmental sensitivity of local residents. Total risk values of different villages near Taihu Lake were calculated in the case study, which resulted in a geographic risk map showing which village was the critical risk source of Taihu eutrophication. The increased application of phosphorus (P) and nitrogen (N), loss vulnerability of pollutant, and a lack of environmental risk awareness led to more serious non-point pollution, especially in rural China. Interesting results revealed by the quotient between the scores of objective risk sources and subjective risk sources showed what should be improved for each study village. More environmental investments, control of agricultural activities, and promotion of environmental education are critical considerations for rural environmental management. These findings are helpful for developing targeted and effective risk management strategies in rural areas.

  6. Utilizing water characteristics and sediment nitrogen isotopic features to identify non-point nitrogen pollution sources at watershed scale in Liaoning Province, China.

    PubMed

    Ma, Jian; Chen, Xin; Huang, Bin; Shi, Yi; Chi, Guangyu; Lu, Caiyan

    2015-02-01

    Identifying nitrogen (N) pollution sources is the fundamental work of non-point source pollution load reduction from watersheds, but is hard due to complex N transport and transformation within spatially heterogenized huge areas. During September 2011, we measured water characteristics and sediment N stable isotope in four tributaries of the upper reach of the Hun River, an important water source of the Dahuofang Reservoir, a large drinking water source in Northeast China. Results showed that spatial changes in SO4 (2-) and Cl(-) contents in the tributaries were consisted with the changes in density of the population living along the tributaries. Sediment δ(15)N from all tributaries showed a downstream increasing trend in line with the land use change, which is characterized as more farmlands and more people around the outlet area of each tributary. Principal component analysis indicated the population density had a strong impact on N in these tributaries in the low-flow period. Tributaries and villages close to the Dahuofang Reservoir should be the major N load control objects in reduction of non-point source nitrogen load from the upper reach of the Hun River.

  7. Modeling the effects of point and non-point source pollution on a diversion channel from Yellow River to an artificial lake in China.

    PubMed

    Gao, X P; Li, G N; Li, G R; Zhang, C

    2015-01-01

    The Dragon lake diversion channel (DLDC) is the only river that recharges Dragon Lake, an artificial lake in China. This paper examines the main factors influencing water quality by investigating point source and non-point source pollutants along the main route. Based on the complicated system of rivers and desilting basins, a three-dimensional water quality model using environmental fluid dynamics code (EFDC) was developed. The model of DLDC was calibrated and verified using observed data. The error ranges of river water level, total phosphorus, total nitrogen and chemical oxygen demand were within 5%, 10%, 16% and 20%, respectively, all of which meet the precision requirement. The model was employed to predict the concentrations of pollutants in the main stream under current pollution loads within a year and a flood lasting for 24 hours. The results revealed that the main pollution sources that influence the water quality of waterways were the point sources followed by the non-point pollution sources. Water quality improved when large water quantities were delivered and this trend can be described as dilution. The water quality of the Dongfeng main channel meets the requirement; however, the water quality of the Dongfeng River is somewhat poor, and the water quality of the Wei River is seriously contaminated. To address these problems, we suggest that the Dongfeng River and Wei River adopt a culvert under its riverbeds.

  8. Detection of spatial fluctuations of non-point source fecal pollution in coral reef surrounding waters in southwestern Puerto Rico using PCR-based assays.

    PubMed

    Bonkosky, M; Hernández-Delgado, E A; Sandoz, B; Robledo, I E; Norat-Ramírez, J; Mattei, H

    2009-01-01

    Human fecal contamination of coral reefs is a major cause of concern. Conventional methods used to monitor microbial water quality cannot be used to discriminate between different fecal pollution sources. Fecal coliforms, enterococci, and human-specific Bacteroides (HF183, HF134), general Bacteroides-Prevotella (GB32), and Clostridium coccoides group (CP) 16S rDNA PCR assays were used to test for the presence of non-point source fecal contamination across the southwestern Puerto Rico shelf. Inshore waters were highly turbid, consistently receiving fecal pollution from variable sources, and showing the highest frequency of positive molecular marker signals. Signals were also detected at offshore waters in compliance with existing microbiological quality regulations. Phylogenetic analysis showed that most isolates were of human fecal origin. The geographic extent of non-point source fecal pollution was large and impacted extensive coral reef systems. This could have deleterious long-term impacts on public health, local fisheries and in tourism potential if not adequately addressed.

  9. Seasonal and spatial variation of diffuse (non-point) source zinc pollution in a historically metal mined river catchment, UK.

    PubMed

    Gozzard, E; Mayes, W M; Potter, H A B; Jarvis, A P

    2011-10-01

    Quantifying diffuse sources of pollution is becoming increasingly important when characterising river catchments in entirety - a prerequisite for environmental management. This study examines both low and high flow events, as well as spatial variability, in order to assess point and diffuse components of zinc pollution within the River West Allen catchment, which lies within the northern England lead-zinc Orefield. Zinc levels in the river are elevated under all flow regimes, and are of environmental concern. Diffuse components are of little importance at low flow, with point source mine water discharges dominating instream zinc concentration and load. During higher river flows 90% of the instream zinc load is attributed to diffuse sources, where inputs from resuspension of metal-rich sediments, and groundwater influx are likely to be more dominant. Remediating point mine water discharges should significantly improve water quality at lower flows, but contribution from diffuse sources will continue to elevate zinc flux at higher flows.

  10. Screening and identification of early warning algal species for metal contamination in fresh water bodies polluted from point and non-point sources.

    PubMed

    Rai, U N; Dubey, Smita; Shukla, O P; Dwivedi, S; Tripathi, R D

    2008-09-01

    The water bodies of Lucknow, Unnao and Kanpur (U.P.), India polluted through various point and non point sources were found to be either eutrophic or oligotrophic in nature. These water bodies supported a great number of algal diversity, which varied seasonally depending upon the physico-chemical properties of water. Further, the water bodies polluted through non point sources supports diverse algal species, while the water bodies polluted through point sources supports growth of tolerant blue green algae. High biomass producing algal species growing in these water bodies have accumulated significant amount of metals in their tissues. Maximum amount of Fe was found accumulated by species of Oedogonium sp. II (20,523.00 microg g(-1) dw) and Spirogyra sp. I (4,520.00 microg g(-1) dw), while maximum Chromium (Cr) was found accumulated in Phormedium bohneri (2,109.00 microg g(-1) dw) followed by Oscillatoria nigra (1,957.88 microg g(-1) dw) and Oedogonium sp. I (156.00 microg g(-1) dw) and Ni in Ulothrix sp. (495.00 microg g(-1) dw). Results showed that some of these forms growing in polluted environment and accumulating high amounts of toxic metals may be used as bioindicator species, however, their performance in metal contaminated water under different ecological niche is to be ascertained.

  11. A dual-inexact fuzzy stochastic model for water resources management and non-point source pollution mitigation under multiple uncertainties

    NASA Astrophysics Data System (ADS)

    Dong, C.; Tan, Q.; Huang, G.-H.; Cai, Y.-P.

    2014-01-01

    In this research, a dual-inexact fuzzy stochastic programming (DIFSP) method was developed for supporting the planning of water and farmland use management system considering the non-point source pollution mitigation under uncertainty. The random boundary interval (RBI) was incorporated into DIFSP through integrating fuzzy programming (FP) and chance-constrained programming (CCP) approaches within an interval linear programming (ILP) framework. The lower and upper bounds of RBI are continuous random variables, and the correlation exiting between the lower and upper bounds can be tackled in RBI through the joint probability distribution function. And thus the subjectivity of decision making is greatly reduced, enhancing the stability and robustness of obtained solutions. The proposed method was then applied to solve a water and farmland use planning model (WFUPM) with non-point source pollution. The generated results could provide decision makers with detailed water supply-demand schemes involving diversified water related activities under various system conditions. These useful solutions could allow more in-depth analyses of the trade-offs between human and environment, as well as those between system optimality and reliability. In addition, comparative analyses on the solutions obtained from ICCP (Interval chance-constraints programming) and DIFSP demonstrated the higher application of this developed approach for supporting the water and farmland use system planning.

  12. A dual-inexact fuzzy stochastic model for water resources management and non-point source pollution mitigation under multiple uncertainties

    NASA Astrophysics Data System (ADS)

    Dong, C.; Tan, Q.; Huang, G.-H.; Cai, Y.-P.

    2014-05-01

    In this research, a dual-inexact fuzzy stochastic programming (DIFSP) method was developed for supporting the planning of water and farmland use management system considering the non-point source pollution mitigation under uncertainty. The random boundary interval (RBI) was incorporated into DIFSP through integrating fuzzy linear programming (FLP) and chance-constrained programming (CCP) approaches within an interval linear programming (ILP) framework. This developed method could effectively tackle the uncertainties expressed as intervals and fuzzy sets. Moreover, the lower and upper bounds of RBI are continuous random variables, and the correlation existing between the lower and upper bounds can be tackled in RBI through the joint probability distribution function. And thus the subjectivity of decision making is greatly reduced, enhancing the stability and robustness of obtained solutions. The proposed method was then applied to solve a water and farmland use planning model (WFUPM) with non-point source pollution mitigation. The generated results could provide decision makers with detailed water supply-demand schemes involving diversified water-related activities under preferred satisfaction degrees. These useful solutions could allow more in-depth analyses of the trade-offs between humans and environment, as well as those between system optimality and reliability. In addition, comparative analyses on the solutions obtained from ICCP (Interval chance-constraints programming) and DIFSP demonstrated the higher application of this developed approach for supporting the water and farmland use system planning.

  13. Reductions in non-point source pollution through different management practices for an agricultural watershed in the Three Gorges Reservoir Area.

    PubMed

    Tian, Yaowu; Huang, Zhilin; Xiao, Wenfa

    2010-01-01

    Non-point source water pollution generated by agricultural production is considered a major environmental issue in the Three Gorges Reservoir Area (TGRA) of China. The Annualised Agricultural Non-Point Source Pollution (AnnAGNPS) model was selected to assess the impact of the application of various management treats, including seven crops, five fertilizer levels and three-group management practice scenarios, on water quality from Heigou River Watershed in TGRA. The scenario subsets include conservation tillage practice (CTP), conservation reserve program (CRP) and conversion of cropland into forestland program (CCFP). Results indicated that tea can not be replaced by other crops because comparatively tea resulted in a higher sediment yield. CTP with no-tillage was more effective to reduce sediment yield, but could increased nutrient loss. CRP reduced sediment yield significantly, but slightly benefited on nutrient loss. CCFP reduced not only sediment yield but also the nutrient loss significantly. The conversion of cropland with a slope greater than 10 degrees into forestland was found to be the best scenario as the sediment yield export is less than 5 tons/ha and nutrient loss is within the permissible limit.

  14. Runoff characteristics and non-point source pollution analysis in the Taihu Lake Basin: a case study of the town of Xueyan, China.

    PubMed

    Zhu, Q D; Sun, J H; Hua, G F; Wang, J H; Wang, H

    2015-10-01

    Non-point source pollution is a significant environmental issue in small watersheds in China. To study the effects of rainfall on pollutants transported by runoff, rainfall was monitored in Xueyan town in the Taihu Lake Basin (TLB) for over 12 consecutive months. The concentrations of different forms of nitrogen (N) and phosphorus (P), and chemical oxygen demand, were monitored in runoff and river water across different land use types. The results indicated that pollutant loads were highly variable. Most N losses due to runoff were found around industrial areas (printing factories), while residential areas exhibited the lowest nitrogen losses through runoff. Nitrate nitrogen (NO3-N) and ammonia nitrogen (NH4-N) were the dominant forms of soluble N around printing factories and hotels, respectively. The levels of N in river water were stable prior to the generation of runoff from a rainfall event, after which they were positively correlated to rainfall intensity. In addition, three sites with different areas were selected for a case study to analyze trends in pollutant levels during two rainfall events, using the AnnAGNPS model. The modeled results generally agreed with the observed data, which suggests that AnnAGNPS can be used successfully for modeling runoff nutrient loading in this region. The conclusions of this study provide important information on controlling non-point source pollution in TLB.

  15. Trends of nitrogen and phosphorus input into Lake Neusiedl from wastewater treatment plants and non-point sources

    NASA Astrophysics Data System (ADS)

    Kinner, Paul; Heiss, Gerhard; Soja, Gerhard

    2013-04-01

    nitrogen load amounted to 304 tons in 2010, compared to 47 tons in 2001. In the period 1992-2010 the nitrogen load caused by diffuse sources was 4.3 times higher than the point source nitrogen load (2 wastewater treatment plants). The proportion of total discharge, of inorganic nitrogen load and of phosphorus load caused by the two wastewater treatment plants depended on the discharge rate of the river Wulka (monitoring station Schützen). In 2001 (low precipitation year: 578 mm annual sum) point sources contributed about 47% of the discharge, 51% of the nitrogen load and 65% of the phosphorus load of the river Wulka. In 2010 (high precipitation year: 945 mm annual sum) point sources contributed 25% of the discharge, 11% of the nitrogen load and 31% of the total phosphorus load. In the period 1992 to 2010 the inorganic nitrogen load caused by surface water (Wulka, WWTP, creeks and channels) varied from 65 t/a to 675 t/a (mean:233 t/a).

  16. Water quality and non-point sources of risk: the Jiulong River Watershed, P. R. of China.

    PubMed

    Zhang, Jingjing; Zhang, Luoping; Ricci, Paolo F

    2012-01-01

    Retrospective water quality assessment plays an essential role in identifying trends and causal associations between exposures and risks, thus it can be a guide for water resources management. We have developed empirical relationships between several time-varying social and economic factors of economic development, water quality variables such as nitrate-nitrogen, COD(Mn), BOD(5), and DO, in the Jiulong River Watershed and its main tributary, the West River. Our analyses used alternative statistical methods to reduce the dimensionality of the analysis first and then strengthen the study's causal associations. The statistical methods included: factor analysis (FA), trend analysis, Monte Carlo/bootstrap simulations, robust regressions and a coupled equations model, integrated into a framework that allows an investigation and resolution of the issues that may affect the estimated results. After resolving these, we found that the concentrations of nitrogen compounds increased over time in the West River region, and that fertilizer used in agricultural fruit crops was the main risk with regard to nitrogen pollution. The relationships we developed can identify hazards and explain the impact of sources of different types of pollution, such as urbanization, and agriculture.

  17. Coupled radon, methane and nitrate sensors for large-scale assessment of groundwater discharge and non-point source pollution to coastal waters.

    PubMed

    Dulaiova, Henrieta; Camilli, Richard; Henderson, Paul B; Charette, Matthew A

    2010-07-01

    We constructed a survey system of radon/methane/nitrate/salinity to find sites of submarine groundwater discharge (SGD) and groundwater nitrate input. We deployed the system in Waquoit Bay and Boston Harbor, MA where we derived SGD rates using a mass balance of radon with methane serving as a fine resolution qualitative indicator of groundwater. In Waquoit Bay we identified several locations of enhanced groundwater discharge, out of which two (Childs and Quashnet Rivers) were studied in more detail. The Childs River was characterized by high nitrate input via groundwater discharge, while the Quashnet River SGD was notable but not a significant source of nitrate. Our radon survey of Boston Harbor revealed several sites with significant SGD, out of these Inner Harbor and parts of Dorchester Bay and Quincy Bay had groundwater fluxes accompanied by significant water column nitrogen concentrations. The survey system has proven effective in revealing areas of SGD and non-point source pollution.

  18. Combination system of full-scale constructed wetlands and wetland paddy fields to remove nitrogen and phosphorus from rural unregulated non-point sources.

    PubMed

    Sun, Haijun; Zhang, Hailin; Yu, Zhimin; Wu, Jiasen; Jiang, Peikun; Yuan, Xiaoyan; Shi, Weiming

    2013-12-01

    Constructed wetlands (CWs) have been used effectively to remove nitrogen (N) and phosphorus (P) from non-point sources. Effluents of some CWs were, however, still with high N and P concentrations and remained to be pollution sources. Widely distributed paddy fields can be exploited to alleviate this concern. We were the first to investigate a combination system of three-level CWs with wetland paddy fields in a full scale to remove N and P from rural unregulated non-point sources. The removal efficiencies (REs) of CWs reached 57.3 % (37.4-75.1 %) for N and 76.3 % (62.0-98.4 %) for P. The CWs retained about 1,278 kg N ha(-1) year(-1) and 121 kg P ha(-1) year(-1). There was a notable seasonal change in REs of N and P, and the REs were different in different processing components of CWs. The removal rates of wetland paddy fields adopt "zero-drainage" water management according to local rainfall forecast and physiological water demand of crop growth reached 93.2 kg N ha(-1) year(-1) and 5.4 kg P ha(-1) year(-1). The rice season had higher potential in removing N and P than that in the wheat season. The whole combined system (0.56 ha CWs and 5.5 ha wetland paddy fields) removed 1,790 kg N year(-1) and 151 kg P year(-1), which were higher than those from CWs functioned alone. However, another 4.7-ha paddy fields were needed to fully remove the N and P in the effluents of CWs. The combination of CWs and paddy fields proved to be a more efficient nutrient removal system.

  19. Spatial and temporal variations in non-point source losses of nitrogen and phosphorus in a small agricultural catchment in the Three Gorges Region.

    PubMed

    Chen, Chenglong; Gao, Ming; Xie, Deti; Ni, Jiupai

    2016-04-01

    Losses of agricultural pollutants from small catchments are a major issue for water quality in the Three Gorges Region. Solutions are urgently needed. However, before pollutant losses can be controlled, information about spatial and temporal variations in pollutant losses is needed. The study was carried out in the Wangjiagou catchment, a small agricultural catchment in Fuling District, Chongqing, and the data about non-point source losses of nitrogen and phosphorus was collected here. Water samples were collected daily by an automatic water sampler at the outlets of two subcatchments from 2012 to 2014. Also, samples of surface runoff from 28 sampling sites distributed through the subcatchments were collected during 12 rainfall events in 2014. A range of water quality variables were analyzed for all samples and were used to demonstrate the variation in non-point losses of nitrogen and phosphorus over a range of temporal and spatial scales and in different types of rainfall in the catchment. Results showed that there was a significant linear correlation between the mass concentrations of total nitrogen (TN) and nitrate (NO3-N) in surface runoff and that the relationship was maintained with changes in time. Concentrations of TN and NO3-N peaked after fertilizer was applied to crops in spring and autumn; concentrations decreased rapidly after the peak values in spring but declined slowly in autumn. N and P concentrations fluctuated more and showed a greater degree of dispersion during the spring crop cultivation period than those in autumn. Concentrations of TN and NO3-N in surface runoff were significantly and positively correlated with the proportion of the area that was planted with corn and mustard tubers, but were negatively correlated with the proportion of the area taken up with rice and mulberry plantations. The average concentrations of TN and NO3-N in surface runoff reached the highest level from the sampling points at the bottom of the land used for corn

  20. Evaluation of non-point source pollution reduction by applying best management practices using a SWAT model and QuickBird high resolution satellite imagery.

    PubMed

    Lee, MiSeon; Park, GeunAe; Park, MinJi; Park, JongYoon; Lee, JiWan; Kim, SeongJoon

    2010-01-01

    This study evaluated the reduction effect of non-point source pollution by applying best management practices (BMPs) to a 1.21 km2 small agricultural watershed using a SWAT (Soil and Water Assessment Tool) model. Two meter QuickBird land use data were prepared for the watershed. The SWAT was calibrated and validated using daily streamflow and monthly water quality (total phosphorus (TP), total nitrogen (TN), and suspended solids (SS)) records from 1999 to 2000 and from 2001 to 2002. The average Nash and Sutcliffe model efficiency was 0.63 for the streamflow and the coefficients of determination were 0.88, 0.72, and 0.68 for SS, TN, and TP, respectively. Four BMP scenarios viz. the application of vegetation filter strip and riparian buffer system, the regulation of Universal Soil Loss Equation P factor, and the fertilizing control amount for crops were applied and analyzed.

  1. Spatial-temporal characteristics of phosphorus in non-point source pollution with grid-based export coefficient model and geographical information system.

    PubMed

    Liu, Ruimin; Dong, Guangxia; Xu, Fei; Wang, Xiujuan; He, Mengchang

    2015-01-01

    In this paper, the spatial changes and trends in non-point source (NPS) total phosphorus (TP) pollution were analyzed by land and non-land uses in the Songliao River Basin from 1986 to 2000 (14 years). A grid-based export coefficient model was used in the process of analysis based on to a geographic information system. The Songliao Basin is divided in four regions: Liaoning province, Jilin province (JL), Heilongjiang province and the eastern part of the Inner Mongolia (IM) Autonomous Region. Results indicated that the NPS phosphorus load caused by land use and non-land use increased steadily from 3.11×10(4) tons in 1986 to 3.49×10(4) tons in 2000. The southeastern region of the Songliao Plain was the most important NPS pollution contributor of all the districts. Although the TP load caused by land use decreased during the studied period in the Songliao River Basin, the contribution of land use to the TP load was dominant compared to non-land uses. The NPS pollution caused by non-land use steadily increased over the studied period. The IM Autonomous Region and JL province had the largest mean annual rate of change among all districts (more than 30%). In this area, livestock and poultry breeding had become one of the most important NPS pollution sources. These areas will need close attention in the future.

  2. A method coupled with remote sensing data to evaluate non-point source pollution in the Xin'anjiang catchment of China.

    PubMed

    Wang, Xuelei; Wang, Qiao; Wu, Chuanqing; Liang, Tao; Zheng, Donghai; Wei, Xingfeng

    2012-07-15

    Non-point source (NPS) pollution has been recognized as the largest threat to water resources throughout the world, and the evaluation of NPS loads is a priority. In China, some models, such as SWAT (Soil and Water Assessment Tools) model, have been widely used at the watershed scale. However, variations in natural and social factors make it difficult to find a proper model to use on NPS pollution management in China. In this study, a "Dualistic Structure" model is coupled with remote sensing data to capture the spatial and temporal processes of NPS pollution. Land parameters were derived from HJ-1A and HJ-1B satellite data (resolution 30 m), which offered greatly enhanced spatial resolution. This approach offers the advantage of being a rapid estimation system with fairly precise knowledge of the distribution, sources and quantities of NPS pollutants, and it can be used at the country scale, including in areas with insufficient data. The method is used in the Xin'anjiang catchment, an important water source for Hangzhou city, China. The simulation in this study includes the spatial distribution of monthly total nitrogen (TN), total phosphorous (TP), ammonia nitrogen (NH(4)-N) and chemical oxygen demand (COD(cr)) loads and the total production of NPS pollutants. The simulations were compared to pollution census (PC) data in 2010 and the results of SWAT model, with an average R(2) larger than 0.7. Additionally, the impacts of soil erosion and human activities on NPS pollution were assessed, indicating that soil and water conservation is very significant factor in the Xin'anjiang catchment. Results indicate that by coupling remote sensing data and parameter retrieval techniques to "Dualistic Structure" models, estimations of NPS loads on the catchment scale can be improved by spatial pixel-based modeling. This rapid NPS estimation system will offer effective support to policy makers for environmental management in China.

  3. A novel approach combining self-organizing map and parallel factor analysis for monitoring water quality of watersheds under non-point source pollution

    PubMed Central

    Zhang, Yixiang; Liang, Xinqiang; Wang, Zhibo; Xu, Lixian

    2015-01-01

    High content of organic matter in the downstream of watersheds underscored the severity of non-point source (NPS) pollution. The major objectives of this study were to characterize and quantify dissolved organic matter (DOM) in watersheds affected by NPS pollution, and to apply self-organizing map (SOM) and parallel factor analysis (PARAFAC) to assess fluorescence properties as proxy indicators for NPS pollution and labor-intensive routine water quality indicators. Water from upstreams and downstreams was sampled to measure dissolved organic carbon (DOC) concentrations and excitation-emission matrix (EEM). Five fluorescence components were modeled with PARAFAC. The regression analysis between PARAFAC intensities (Fmax) and raw EEM measurements indicated that several raw fluorescence measurements at target excitation-emission wavelength region could provide similar DOM information to massive EEM measurements combined with PARAFAC. Regression analysis between DOC concentration and raw EEM measurements suggested that some regions in raw EEM could be used as surrogates for labor-intensive routine indicators. SOM can be used to visualize the occurrence of pollution. Relationship between DOC concentration and PARAFAC components analyzed with SOM suggested that PARAFAC component 2 might be the major part of bulk DOC and could be recognized as a proxy indicator to predict the DOC concentration. PMID:26526140

  4. A paddy eco-ditch and wetland system to reduce non-point source pollution from rice-based production system while maintaining water use efficiency.

    PubMed

    Xiong, Yujiang; Peng, Shizhang; Luo, Yufeng; Xu, Junzeng; Yang, Shihong

    2015-03-01

    Non-point source (NPS) pollution from agricultural drainage has aroused widespread concerns throughout the world due to its contribution to eutrophication of water bodies. To remove nitrogen (N) and phosphorus (P) from agricultural drainage in situ, a Paddy Eco-ditch and Wetland System (PEDWS) was designed and built based on the characteristics of the irrigated rice district. A 2-year (2012-2013) field experiment was conducted to evaluate the performance of this system in Gaoyou Irrigation District in Eastern China. The results showed that the reduction in water input in paddy field of the PEDWS enabled the maintenance of high rice yield; it significantly increased irrigation water productivity (WPI), gross water productivity (WPG), and evapotranspiration water productivity (WPET) by 109.2, 67.1, and 17.6%, respectively. The PEDWS dramatically decreased N and P losses from paddy field. Compared with conventional irrigation and drainage system (CIDS), the amount of drainage water from PEDWS was significantly reduced by 56.2%, the total nitrogen (TN) concentration in drainage was reduced by 42.6%, and thus the TN and total phosphorus (TP) losses were reduced by 87.8 and 70.4%. PEDWS is technologically feasible and applicable to treat nutrient losses from paddy fields in situ and can be used in similar areas.

  5. A novel approach combining self-organizing map and parallel factor analysis for monitoring water quality of watersheds under non-point source pollution.

    PubMed

    Zhang, Yixiang; Liang, Xinqiang; Wang, Zhibo; Xu, Lixian

    2015-11-03

    High content of organic matter in the downstream of watersheds underscored the severity of non-point source (NPS) pollution. The major objectives of this study were to characterize and quantify dissolved organic matter (DOM) in watersheds affected by NPS pollution, and to apply self-organizing map (SOM) and parallel factor analysis (PARAFAC) to assess fluorescence properties as proxy indicators for NPS pollution and labor-intensive routine water quality indicators. Water from upstreams and downstreams was sampled to measure dissolved organic carbon (DOC) concentrations and excitation-emission matrix (EEM). Five fluorescence components were modeled with PARAFAC. The regression analysis between PARAFAC intensities (Fmax) and raw EEM measurements indicated that several raw fluorescence measurements at target excitation-emission wavelength region could provide similar DOM information to massive EEM measurements combined with PARAFAC. Regression analysis between DOC concentration and raw EEM measurements suggested that some regions in raw EEM could be used as surrogates for labor-intensive routine indicators. SOM can be used to visualize the occurrence of pollution. Relationship between DOC concentration and PARAFAC components analyzed with SOM suggested that PARAFAC component 2 might be the major part of bulk DOC and could be recognized as a proxy indicator to predict the DOC concentration.

  6. Using a constructed wetland for non-point source pollution control and river water quality purification: a case study in Taiwan.

    PubMed

    Wu, C Y; Kao, C M; Lin, C E; Chen, C W; Lai, Y C

    2010-01-01

    The Kaoping River Rail Bridge Constructed Wetland, which was commissioned in 2004, is one of the largest constructed wetlands in Taiwan. This multi-function wetland has been designed for the purposes of non-point source (NPS) pollutant removal, wastewater treatment, wildlife habitat, recreation, and education. The major influents of this wetland came from the local drainage trench containing domestic, agricultural, and industrial wastewaters, and effluents from the wastewater treatment plant of a paper mill. Based on the quarterly investigation results from 2007 to 2009, more than 96% of total coliforms (TC), 48% of biochemical oxygen demand (BOD), and 40% of nutrients (e.g. total nitrogen, total phosphorus) were removed via the constructed wetland system. Thus, the wetland system has a significant effect on water quality improvement and is capable of removing most of the pollutants from the local drainage system before they are discharged into the downgradient water body. Other accomplishments of this constructed wetland system include the following: providing more green areas along the riversides, offering more water assessable eco-ponds and eco-gardens for the public, and rehabilitating the natural ecosystem. The Kaoping River Rail Bridge Constructed Wetland has become one of the most successful multi-function constructed wetlands in Taiwan. The experience obtained from this study will be helpful in designing similar natural treatment systems for river water quality improvement and wastewater treatment.

  7. Evaluating the Effects of Land Use Planning for Non-Point Source Pollution Based on a System Dynamics Approach in China.

    PubMed

    Kuai, Peng; Li, Wei; Liu, Nianfeng

    2015-01-01

    Urbanization is proceeding rapidly in several developing countries such as China. This accelerating urbanization alters the existing land use types in a way that results in more Non-Point Source (NPS) pollution to local surface waters. Reasonable land use planning is necessary. This paper compares seven planning scenarios of a case study area, namely Wulijie, China, from the perspective of NPS pollution. A System Dynamics (SD) model was built for the comparison to adequately capture the planning complexity. These planning scenarios, which were developed by combining different land use intensities (LUIs) and construction speeds (CSs), were then simulated. The results show that compared to scenario S1 (business as usual) all other scenarios will introduce more NPS pollution (with an incremental rate of 22%-70%) to Wulijie. Scenario S6 was selected as the best because it induced relatively less NPS pollution while simultaneously maintaining a considerable development rate. Although LUIs represent a more critical factor compared to CSs, we conclude that both LUIs and CSs need to be taken into account to make the planning more environmentally friendly. Considering the power of SD in decision support, it is recommended that land use planning should take into consideration findings acquired from SD simulations.

  8. A simulation-based interval two-stage stochastic model for agricultural non-point source pollution control through land retirement.

    PubMed

    Luo, B; Li, J B; Huang, G H; Li, H L

    2006-05-15

    This study presents a simulation-based interval two-stage stochastic programming (SITSP) model for agricultural non-point source (NPS) pollution control through land retirement under uncertain conditions. The modeling framework was established by the development of an interval two-stage stochastic program, with its random parameters being provided by the statistical analysis of the simulation outcomes of a distributed water quality approach. The developed model can deal with the tradeoff between agricultural revenue and "off-site" water quality concern under random effluent discharge for a land retirement scheme through minimizing the expected value of long-term total economic and environmental cost. In addition, the uncertainties presented as interval numbers in the agriculture-water system can be effectively quantified with the interval programming. By subdividing the whole agricultural watershed into different zones, the most pollution-related sensitive cropland can be identified and an optimal land retirement scheme can be obtained through the modeling approach. The developed method was applied to the Swift Current Creek watershed in Canada for soil erosion control through land retirement. The Hydrological Simulation Program-FORTRAN (HSPF) was used to simulate the sediment information for this case study. Obtained results indicate that the total economic and environmental cost of the entire agriculture-water system can be limited within an interval value for the optimal land retirement schemes. Meanwhile, a best and worst land retirement scheme was obtained for the study watershed under various uncertainties.

  9. Designing Schemes to Mitigate Non-Point Source Water Pollution from Agriculture: The Value of High-Resolution Hydrochemical and Hydrophysical Data

    NASA Astrophysics Data System (ADS)

    Barber, N.; Reaney, S. M.

    2014-12-01

    To effectively mitigate non-point source water pollution from agriculture, first it is vital to have an awareness of a watershed's hydrological and contaminant regime. Understanding the magnitude and timing of pollutant export, as well as the pathways by which different constituents are delivered to a water course, is paramount. One approach to gaining this type of knowledge is to observe pollutant fluxes at the watershed outlet. The River Eden Demonstration Test Catchments programme uses in-situ monitoring equipment to provide high-resolution (30 minute) data for three mixed-agriculture watersheds (ca. 10km2) in north western England. Determinands measured include turbidity, phosphorus, nitrate, chlorophyll-a, dissolved oxygen, conductivity, pH and temperature, along with river discharge and rainfall. Provided with these data, and an awareness of significant agricultural activities carried out in the watershed on an annual basis, this study demonstrates how it is possible to identify different pollutant transfer pathways, along with their spatio-temporal nature, and their relative importance. This information is then used to inform appropriate mitigation design. In relation to this purpose, the pros and cons of the different hydrochemical and hydrophysical data are described, and recommendations made for other determinands that should be considered for measurement in future similar studies.

  10. Evaluating the Effects of Land Use Planning for Non-Point Source Pollution Based on a System Dynamics Approach in China

    PubMed Central

    Kuai, Peng; Li, Wei; Liu, Nianfeng

    2015-01-01

    Urbanization is proceeding rapidly in several developing countries such as China. This accelerating urbanization alters the existing land use types in a way that results in more Non-Point Source (NPS) pollution to local surface waters. Reasonable land use planning is necessary. This paper compares seven planning scenarios of a case study area, namely Wulijie, China, from the perspective of NPS pollution. A System Dynamics (SD) model was built for the comparison to adequately capture the planning complexity. These planning scenarios, which were developed by combining different land use intensities (LUIs) and construction speeds (CSs), were then simulated. The results show that compared to scenario S1 (business as usual) all other scenarios will introduce more NPS pollution (with an incremental rate of 22%-70%) to Wulijie. Scenario S6 was selected as the best because it induced relatively less NPS pollution while simultaneously maintaining a considerable development rate. Although LUIs represent a more critical factor compared to CSs, we conclude that both LUIs and CSs need to be taken into account to make the planning more environmentally friendly. Considering the power of SD in decision support, it is recommended that land use planning should take into consideration findings acquired from SD simulations. PMID:26267482

  11. Geospatial data resampling and resolution effects on watershed modeling: A case study using the agricultural non-point source pollution model

    USGS Publications Warehouse

    Usery, E.L.; Finn, M.P.; Scheidt, D.J.; Ruhl, S.; Beard, T.; Bearden, M.

    2004-01-01

    Researchers have been coupling geographic information systems (GIS) data handling and processing capability to watershed and waterquality models for many years. This capability is suited for the development of databases appropriate for water modeling. However, it is rare for GIS to provide direct inputs to the models. To demonstrate the logical procedure of coupling GIS for model parameter extraction, we selected the Agricultural Non-Point Source (AGNPS) pollution model. Investigators can generate data layers at various resolutions and resample to pixel sizes to support models at particular scales. We developed databases of elevation, land cover, and soils at various resolutions in four watersheds. The ability to use multiresolution databases for the generation of model parameters is problematic for grid-based models. We used database development procedures and observed the effects of resolution and resampling on GIS input datasets and parameters generated from those inputs for AGNPS. Results indicate that elevation values at specific points compare favorably between 3- and 30-m raster datasets. Categorical data analysis indicates that land cover classes vary significantly. Derived parameters parallel the results of the base GIS datasets. Analysis of data resampled from 30-m to 60-, 120-, 210-, 240-, 480-, 960-, and 1920-m pixels indicates a general degradation of both elevation and land cover correlations as resolution decreases. Initial evaluation of model output values for soluble nitrogen and phosphorous indicates similar degradation with resolution. ?? Springer-Verlag 2004.

  12. Comparative study on nutrient removal of agricultural non-point source pollution for three filter media filling schemes in eco-soil reactors.

    PubMed

    Du, Fuyi; Xie, Qingjie; Fang, Longxiang; Su, Hang

    2016-08-01

    Nutrients (nitrogen and phosphorus) from agricultural non-point source (NPS) pollution have been increasingly recognized as a major contributor to the deterioration of water quality in recent years. The purpose of this article is to investigate the discrepancies in interception of nutrients in agricultural NPS pollution for eco-soil reactors using different filling schemes. Parallel eco-soil reactors of laboratory scale were created and filled with filter media, such as grit, zeolite, limestone, and gravel. Three filling schemes were adopted: increasing-sized filling (I-filling), decreasing-sized filling (D-filling), and blend-sized filling (B-filling). The systems were intermittent operations via simulated rainstorm runoff. The nutrient removal efficiency, biomass accumulation and vertical dissolved oxygen (DO) distribution were defined to assess the performance of eco-soil. The results showed that B-filling reactor presented an ideal DO for partial nitrification-denitrification across the eco-soil, and B-filling was the most stable in the change of bio-film accumulation trends with depth in the three fillings. Simultaneous and highest removals of NH4(+)-N (57.74-70.52%), total nitrogen (43.69-54.50%), and total phosphorus (42.50-55.00%) were obtained in the B-filling, demonstrating the efficiency of the blend filling schemes of eco-soil for oxygen transfer and biomass accumulation to cope with agricultural NPS pollution.

  13. Export of non-point source suspended sediment, nitrogen, and phosphorus from sloping highland agricultural fields in the East Asian monsoon region.

    PubMed

    Reza, Arif; Eum, Jaesung; Jung, Sungmin; Choi, Youngsoon; Owen, Jeffrey S; Kim, Bomchul

    2016-12-01

    Excess sediment and nutrient export from agricultural fields with steep slopes is a major concern linked to surface water quality in Korea. In this study, the export of suspended sediment (SS), total nitrogen (TN), and total phosphorus (TP) and their event mean concentrations (EMCs) in surface runoff from a highland mixed land use (61% forested, 30% cropped, 9% other) watershed were quantified. In 2007, the Korean Ministry of Environment (MoE) declared the study area as a priority region for non-point source (NPS) pollution management and initiated various best management practices (BMPs) in the study watershed. SS, TN, and TP concentrations in Mandae Stream were monitored for 5 years (2009-2013) to evaluate the effectiveness of BMPs. Average EMCs for SS, TN, and TP were as high as 986, 3.4 and 0.8 mg/L, respectively. The agricultural export coefficients of agricultural land in the study watershed for SS, TN, and TP were 5611, 171, and 6.83 kg/ha/year, respectively. A comparison with results from other studies shows that both EMCs and agricultural export coefficients in the study watershed were much higher than most of the results reported for watersheds in other regions. The results show that sediment and nutrient export from intensive agriculture areas with steep slopes continue to be a major concern for the downstream reservoir, Lake Soyang. Remedial strategies should be directed towards controlling sources of SS, TN, and TP to improve downstream water quality in sloping highland agricultural areas in Korea.

  14. Application of modified export coefficient method on the load estimation of non-point source nitrogen and phosphorus pollution of soil and water loss in semiarid regions.

    PubMed

    Wu, Lei; Gao, Jian-en; Ma, Xiao-yi; Li, Dan

    2015-07-01

    Chinese Loess Plateau is considered as one of the most serious soil loss regions in the world, its annual sediment output accounts for 90 % of the total sediment loads of the Yellow River, and most of the Loess Plateau has a very typical characteristic of "soil and water flow together", and water flow in this area performs with a high sand content. Serious soil loss results in nitrogen and phosphorus loss of soil. Special processes of water and soil in the Loess Plateau lead to the loss mechanisms of water, sediment, nitrogen, and phosphorus are different from each other, which are greatly different from other areas of China. In this study, the modified export coefficient method considering the rainfall erosivity factor was proposed to simulate and evaluate non-point source (NPS) nitrogen and phosphorus loss load caused by soil and water loss in the Yanhe River basin of the hilly and gully area, Loess Plateau. The results indicate that (1) compared with the traditional export coefficient method, annual differences of NPS total nitrogen (TN) and total phosphorus (TP) load after considering the rainfall erosivity factor are obvious; it is more in line with the general law of NPS pollution formation in a watershed, and it can reflect the annual variability of NPS pollution more accurately. (2) Under the traditional and modified conditions, annual changes of NPS TN and TP load in four counties (districts) took on the similar trends from 1999 to 2008; the load emission intensity not only is closely related to rainfall intensity but also to the regional distribution of land use and other pollution sources. (3) The output structure, source composition, and contribution rate of NPS pollution load under the modified method are basically the same with the traditional method. The average output structure of TN from land use and rural life is about 66.5 and 17.1 %, the TP is about 53.8 and 32.7 %; the maximum source composition of TN (59 %) is farmland; the maximum source

  15. Synergistic impacts of land-use change and soil property variation on non-point source nitrogen pollution in a freeze-thaw area

    NASA Astrophysics Data System (ADS)

    Ouyang, Wei; Huang, Haobo; Hao, Fanghua; Guo, Bobo

    2013-07-01

    Quantifying the non-point source (NPS) nitrogen pollution response to the varied land-use and soil properties in highly agricultural regions is critical for the proper management of NPS pollution. This study simulated the NPS nitrogen loading responses to variations of land-use and soil from 1979 to 2009. The Soil and Water Assessment Tool (SWAT) was used to model the NPS organic nitrogen and nitrate loading in a freeze-thaw area in northeast China. The temporal-spatial simulations of land-use in four periods indicated that the NPS nitrogen loading responded to the disappearance of wetlands and the conversion of uplands to paddy rice. After updating the soil data, the watershed NPS nitrogen loading decreased, and the spatial distribution of the loading indicated that the NPS organic nitrogen was more sensitive than was the nitrate to soil variation. F-tests were employed to assess the significance of each of the predictor variables in five types of scenarios. Overall, the results indicate that the watershed NPS nitrogen loading is sensitive to changes of soil and land-use, but soil changes have a more significant impact. The results of this study also suggest that temperature has significant effects on NPS nitrogen yield and that it caused the twin peaks in the temporal scale. Increasing the temperature above zero in April caused a temporal shift in soil water movement and transported nitrogen pollution earlier in the year, causing an increased loading in water before the summer irrigation, which is advantageous for NPS nitrogen pollution control.

  16. Contingent Valuation of Residents' Attitudes and Willingness-to-Pay for Non-point Source Pollution Control: A Case Study in AL-Prespa, Southeastern Albania

    NASA Astrophysics Data System (ADS)

    Grazhdani, Dorina

    2015-07-01

    Recently, local governments in Albania have begun paying attention to management of small watershed, because there are specific boundaries and people living within a watershed basin tend to be more concerned about the basin's environmental, economic, and social development. But this natural resource management and non-point source (NPS) pollution control is still facing challenges. Albanian part of Prespa Park (AL-Prespa) is a good case study, as it is a protected wetland area of high biodiversity and long human history. In this framework, this study was undertaken, the main objectives of which were to explore: (1) the attitudes of the residents toward NPS pollution control, (2) their willingness-to-pay for improving water quality, and (3) factors affecting the residents' willingness-to-pay. Descriptive statistics, one-way ANOVA (analysis of variance), Chi-square analysis, and multivariate data analysis techniques were used. Findings strongly suggested that the residents' attitudes toward NPS pollution control in this area were positive. With the combination of two major contingent valuation methods—dichotomous choice and open-ended formats, the survey results indicated that the average yearly respondents' WTP was €6.4. The survey revealed that residents' yearly income and education level were the main factors affecting residents' willingness-to-pay for NPS pollution control in this area, and there was no significant correlation between residents' yearly income and their education level. The current study would lay a solid foundation on decision-making in further NPS pollution control and public participation through community-based watershed management policies in AL-Prespa watershed and similar areas.

  17. A review of vegetated buffers and a meta-analysis of their mitigation efficacy in reducing non-point source pollution

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Liu, X.; Zhang, M.; Dahlgren, R. A.; Eitzel, M.

    2009-12-01

    Vegetated buffers are a well-studied and widely used agricultural management practice for reducing non-point source pollution. A wealth of literature provides experimental data on their mitigation efficacy. This paper aggregated many of these results and performed a meta-analysis to quantify the relationships between pollutant removal efficacy and buffer width, buffer slope, soil type, and vegetation type. Theoretical models for removal efficacy (Y) vs. buffer width (w) were derived and tested against data from the surveyed literature using statistical analyses. A model of the form Y = K x (1-exp(-b x w) , (0< K <= 100) successfully captured the relationship between buffer width and pollutant removal, where K reflects the maximum removal efficacy of the buffer and b reflects its probability to remove any single particle of pollutant in a unit distance. The estimates of K were 90.9, 93.2, 92.0, and 89.5 for sediment, pesticides, nitrogen (N) and phosphorus (P), respectively. Buffer width alone explains 37, 60, 44 and 35% of the total variance in removal efficacy for sediment, pesticides, N and P, respectively. Buffer slope was linearly associated with sediment removal efficacy either positively (when slope ≤ 10%) or negatively (when slope > 10%). Buffers composed of trees have higher N and P removal efficacy than buffers composed of grasses or mixtures of grasses and trees. Soil drainage type did not show a significant effect on pollutant removal efficacy. Models for all the studied pollutants were statistically significant with P-values < 0.001. Based on our analysis, a 30 m buffer under favorable slope conditions (≈ 10%) removes over 85% of all the studied pollutants. These models predicting optimal buffer width/slope can be instrumental in the design, implementation and modeling of vegetated buffers for treating agricultural runoff.

  18. Spatio-temporal variation of erosion-type non-point source pollution in a small watershed of hilly and gully region, Chinese Loess Plateau.

    PubMed

    Wu, Lei; Liu, Xia; Ma, Xiao-Yi

    2016-06-01

    Loss of nitrogen and phosphorus in the hilly and gully region of Chinese Loess Plateau not only decreases the utilization rate of fertilizer but also is a potential threat to aquatic environments. In order to explore the process of erosion-type non-point source (NPS) pollution in Majiagou watershed of Loess Plateau, a distributed, dynamic, and integrated NPS pollution model was established to investigate impacts of returning farmland on erosion-type NPS pollution load from 1995 to 2012. Results indicate that (1) the integrated model proposed in this study was verified to be reasonable; the general methodology is universal and can be applicable to the hilly and gully region, Loess Plateau; (2) the erosion-type NPS total nitrogen (TN) and total phosphorus (TP) load showed an overall decreasing trend; the average nitrogen and phosphorus load modulus in the last four years (2009-2012) were 1.23 and 1.63 t/km(2) · a, respectively, which were both decreased by about 35.4 % compared with the initial treatment period (1995-1998); and (3) The spatial variations of NPS pollution are closely related to spatial characteristics of rainfall, topography, and soil and land use types; the peak regions of TN and TP loss mainly occurred along the main river banks of the Yanhe River watershed from northeast to southeast, and gradually decreased with the increase of distance to the left and right river banks, respectively. Results may provide scientific basis for the watershed-scale NPS pollution control of the Loess Plateau.

  19. Evaluating spatial interaction of soil property with non-point source pollution at watershed scale: the phosphorus indicator in Northeast China.

    PubMed

    Ouyang, Wei; Huang, Haobo; Hao, Fanghua; Shan, Yushu; Guo, Bobo

    2012-08-15

    To better understand the spatial dynamics of non-point source (NPS) phosphorus loading with soil property at watershed scale, integrated modeling and soil chemistry is crucial to ensure that the indicator is functioning properly and expressing the spatial interaction at two depths. Developments in distributed modeling have greatly enriched the availability of geospatial data analysis and assess the NPS pollution loading response to soil property over larger area. The 1.5 km-grid soil sampling at two depths was analyzed with eight parameters, which provided detailed spatial and vertical soil data under four main types of landuses. The impacts of landuse conversion and agricultural practice on soil property were firstly identified. Except for the slightly bigger total of potassium (TK) and cadmium (Cr), the other six parameters had larger content in 20-40 cm surface than the top 20 cm surface. The Soil and Water Assessment Tool was employed to simulate the loading of NPS phosphorus. Overlaying with the landuse distribution, it was found that the NPS phosphorus mainly comes from the subbasins dominated with upland and paddy rice. The linear correlations of eight soil parameters at two depths with NPS phosphorus loading in the subbasins of upland and paddy rice were compared, respectively. The correlations of available phosphorus (AP), total phosphorus (TP), total nitrogen (TN) and TK varied in two depths, and also can assess the loading. The soil with lower soil organic carbon (SOC) presented a significant higher risk for NPS phosphorus loading, especially in agricultural area. The Principal Component Analysis showed that the TP and zinc (Zn) in top soil and copper (Cu) and Cr in subsurface can work as indicators. The analysis suggested that the application of soil property indicators is useful for assessing NPS phosphorus loss, which is promising for water safety in agricultural area.

  20. Contingent Valuation of Residents' Attitudes and Willingness-to-Pay for Non-point Source Pollution Control: A Case Study in AL-Prespa, Southeastern Albania.

    PubMed

    Grazhdani, Dorina

    2015-07-01

    Recently, local governments in Albania have begun paying attention to management of small watershed, because there are specific boundaries and people living within a watershed basin tend to be more concerned about the basin's environmental, economic, and social development. But this natural resource management and non-point source (NPS) pollution control is still facing challenges. Albanian part of Prespa Park (AL-Prespa) is a good case study, as it is a protected wetland area of high biodiversity and long human history. In this framework, this study was undertaken, the main objectives of which were to explore: (1) the attitudes of the residents toward NPS pollution control, (2) their willingness-to-pay for improving water quality, and (3) factors affecting the residents' willingness-to-pay. Descriptive statistics, one-way ANOVA (analysis of variance), Chi-square analysis, and multivariate data analysis techniques were used. Findings strongly suggested that the residents' attitudes toward NPS pollution control in this area were positive. With the combination of two major contingent valuation methods--dichotomous choice and open-ended formats, the survey results indicated that the average yearly respondents' WTP was 6.4. The survey revealed that residents' yearly income and education level were the main factors affecting residents' willingness-to-pay for NPS pollution control in this area, and there was no significant correlation between residents' yearly income and their education level. The current study would lay a solid foundation on decision-making in further NPS pollution control and public participation through community-based watershed management policies in AL-Prespa watershed and similar areas.

  1. A novel modelling framework to prioritize estimation of non-point source pollution parameters for quantifying pollutant origin and discharge in urban catchments.

    PubMed

    Fraga, I; Charters, F J; O'Sullivan, A D; Cochrane, T A

    2016-02-01

    Stormwater runoff in urban catchments contains heavy metals (zinc, copper, lead) and suspended solids (TSS) which can substantially degrade urban waterways. To identify these pollutant sources and quantify their loads the MEDUSA (Modelled Estimates of Discharges for Urban Stormwater Assessments) modelling framework was developed. The model quantifies pollutant build-up and wash-off from individual impervious roof, road and car park surfaces for individual rain events, incorporating differences in pollutant dynamics between surface types and rainfall characteristics. This requires delineating all impervious surfaces and their material types, the drainage network, rainfall characteristics and coefficients for the pollutant dynamics equations. An example application of the model to a small urban catchment demonstrates how the model can be used to identify the magnitude of pollutant loads, their spatial origin and the response of the catchment to changes in specific rainfall characteristics. A sensitivity analysis then identifies the key parameters influencing each pollutant load within the stormwater given the catchment characteristics, which allows development of a targeted calibration process that will enhance the certainty of the model outputs, while minimizing the data collection required for effective calibration. A detailed explanation of the modelling framework and pre-calibration sensitivity analysis is presented.

  2. The urban atmosphere as a non-point source for the transport of MTBE and other volatile organic compounds (VOCS) to shallow groundwater

    USGS Publications Warehouse

    Pankow, J.F.; Thomson, N.R.; Johnson, R.L.; Baehr, A.L.; Zogorski, J.S.

    1997-01-01

    all no- net recharge cases. The mechanism responsible for this effect was the dispersion acting on each downward infiltration event, and also on the ET-induced flow. The ability of MTBE to reach groundwater in cases 2-5 is taken as evidence of the potential importance of urban air as a non-point source for VOCs in shallow urban groundwater. Two subcases were run for both case 4 and case 5: subcase a (water and VOCs move with ET) and subcase b (water only moves with ET).Numerical simulations were conducted using a 1-D model domain set in medium sand to provide a test of whether methyl-tert-butyl ether (MTBE) and other atmospheric volatile organic compounds could move to shallow groundwater within the 10-15 y time frame over which MTBE was used in large amounts. The gasoline additive MTBE is of special interest because of its: current levels in some urban air; strong partitioning from air into water; resistance to degradation; use as an octane-booster since the 1970s; rapidly increasing use in the 1990s to reduce CO and O3 in urban air; and its frequent detection at low microgram per liter levels in shallow urban groundwater.

  3. Assessment and Delineation of DNAPL Source Zones at Hazardous Waste Sites

    EPA Science Inventory

    This document provides a framework to assess the presence of DNAPL in the subsurface and for delineating the spatial extent of a DNAPL source zone. Direct and indirect site investigation methods are discussed, as well as their applicability in unconsolidated deposits and fracture...

  4. Non-Point Source Pollutant Load Variation in Rapid Urbanization Areas by Remote Sensing, Gis and the L-THIA Model: A Case in Bao'an District, Shenzhen, China

    NASA Astrophysics Data System (ADS)

    Li, Tianhong; Bai, Fengjiao; Han, Peng; Zhang, Yuanyan

    2016-11-01

    Urban sprawl is a major driving force that alters local and regional hydrology and increases non-point source pollution. Using the Bao'an District in Shenzhen, China, a typical rapid urbanization area, as the study area and land-use change maps from 1988 to 2014 that were obtained by remote sensing, the contributions of different land-use types to NPS pollutant production were assessed with a localized long-term hydrologic impact assessment (L-THIA) model. The results show that the non-point source pollution load changed significantly both in terms of magnitude and spatial distribution. The loads of chemical oxygen demand, total suspended substances, total nitrogen and total phosphorus were affected by the interactions between event mean concentration and the magnitude of changes in land-use acreages and the spatial distribution. From 1988 to 2014, the loads of chemical oxygen demand, suspended substances and total phosphorus showed clearly increasing trends with rates of 132.48 %, 32.52 % and 38.76 %, respectively, while the load of total nitrogen decreased by 71.52 %. The immigrant population ratio was selected as an indicator to represent the level of rapid urbanization and industrialization in the study area, and a comparison analysis of the indicator with the four non-point source loads demonstrated that the chemical oxygen demand, total phosphorus and total nitrogen loads are linearly related to the immigrant population ratio. The results provide useful information for environmental improvement and city management in the study area.

  5. Delineating incised stream sediment sources within a San Francisco Bay tributary basin

    NASA Astrophysics Data System (ADS)

    Bigelow, Paul; Benda, Lee; Pearce, Sarah

    2016-07-01

    Erosion and sedimentation pose ubiquitous problems for land and watershed managers, requiring delineation of sediment sources and sinks across landscapes. However, the technical complexity of many spatially explicit erosion models precludes their use by practitioners. To address this critical gap, we demonstrate a contemporary use of applied geomorphometry through a straightforward GIS analysis of sediment sources in the San Francisco Bay Area in California, USA, designed to support erosion reduction strategies. Using 2 m lidar digital elevation models, we delineated the entire river network in the Arroyo Mocho watershed (573 km2) at the scale of ˜ 30 m segments and identified incised landforms using a combination of hillslope gradient and planform curvature. Chronic erosion to the channel network was estimated based on these topographic attributes and the size of vegetation, and calibrated to sediment gage data, providing a spatially explicit estimate of sediment yield from incised channels across the basin. Rates of erosion were summarized downstream through the channel network, revealing patterns of sediment supply at the reach scale. Erosion and sediment supply were also aggregated to subbasins, allowing comparative analyses at the scale of tributaries. The erosion patterns delineated using this approach provide land use planners with a robust framework to design erosion reduction strategies. More broadly, the study demonstrates a modern analysis of important geomorphic processes affected by land use that is easily applied by agencies to solve common problems in watersheds, improving the integration between science and environmental management.

  6. LNAPL source zone delineation using soil gases in a heterogeneous silty-sand aquifer.

    PubMed

    Cohen, Grégory J V; Jousse, Florie; Luze, Nicolas; Höhener, Patrick; Atteia, Olivier

    2016-09-01

    Source delineation of hydrocarbon contaminated sites is of high importance for remediation work. However, traditional methods like soil core extraction and analysis or recent Membrane Interface Probe methods are time consuming and costly. Therefore, the development of an in situ method based on soil gas analysis can be interesting. This includes the direct measurement of volatile organic compounds (VOCs) in soil gas taken from gas probes using a PID (Photo Ionization Detector) and the analysis of other soil gases related to VOC degradation distribution (CH4, O2, CO2) or related to presence of Light Non-Aqueous Phase Liquid (LNAPL) as (222)Rn. However, in widespread heterogeneous formations, delineation by gas measurements becomes more challenging. The objective of this study is twofold: (i) to analyse the potential of several in situ gas measurement techniques in comparison to soil coring for LNAPL source delineation at a heterogeneous contaminated site where the techniques might be limited by a low diffusion potential linked to the presence of fine sands and silts, and (ii) to analyse the effect of vertical sediment heterogeneities on the performance of these gas measurement methods. Thus, five types of gases were analysed: VOCs, their three related degradation products O2, CO2 and CH4 and (222)Rn. Gas measurements were compared to independent LNAPL analysis by coring. This work was conducted at an old industrial site frequently contaminated by a Diesel-Fuel mixture located in a heterogeneous fine-grained aquifer. Results show that in such heterogeneous media migration of reactive gases like VOCs occurs only across small distances and the VOC concentrations sampled with gas probes are mainly related to local conditions rather than the presence of LNAPL below the gas probe. (222)Rn is not well correlated with LNAPL because of sediment heterogeneity. Oxygen, CO2, and especially CH4, have larger lengths of diffusion and give the clearest picture for LNAPL presence at

  7. LNAPL source zone delineation using soil gases in a heterogeneous silty-sand aquifer

    NASA Astrophysics Data System (ADS)

    Cohen, Grégory J. V.; Jousse, Florie; Luze, Nicolas; Höhener, Patrick; Atteia, Olivier

    2016-09-01

    Source delineation of hydrocarbon contaminated sites is of high importance for remediation work. However, traditional methods like soil core extraction and analysis or recent Membrane Interface Probe methods are time consuming and costly. Therefore, the development of an in situ method based on soil gas analysis can be interesting. This includes the direct measurement of volatile organic compounds (VOCs) in soil gas taken from gas probes using a PID (Photo Ionization Detector) and the analysis of other soil gases related to VOC degradation distribution (CH4, O2, CO2) or related to presence of Light Non-Aqueous Phase Liquid (LNAPL) as 222Rn. However, in widespread heterogeneous formations, delineation by gas measurements becomes more challenging. The objective of this study is twofold: (i) to analyse the potential of several in situ gas measurement techniques in comparison to soil coring for LNAPL source delineation at a heterogeneous contaminated site where the techniques might be limited by a low diffusion potential linked to the presence of fine sands and silts, and (ii) to analyse the effect of vertical sediment heterogeneities on the performance of these gas measurement methods. Thus, five types of gases were analysed: VOCs, their three related degradation products O2, CO2 and CH4 and 222Rn. Gas measurements were compared to independent LNAPL analysis by coring. This work was conducted at an old industrial site frequently contaminated by a Diesel-Fuel mixture located in a heterogeneous fine-grained aquifer. Results show that in such heterogeneous media migration of reactive gases like VOCs occurs only across small distances and the VOC concentrations sampled with gas probes are mainly related to local conditions rather than the presence of LNAPL below the gas probe. 222Rn is not well correlated with LNAPL because of sediment heterogeneity. Oxygen, CO2, and especially CH4, have larger lengths of diffusion and give the clearest picture for LNAPL presence at this

  8. Non-Point Source Pollutant Load Variation in Rapid Urbanization Areas by Remote Sensing, Gis and the L-THIA Model: A Case in Bao'an District, Shenzhen, China.

    PubMed

    Li, Tianhong; Bai, Fengjiao; Han, Peng; Zhang, Yuanyan

    2016-11-01

    Urban sprawl is a major driving force that alters local and regional hydrology and increases non-point source pollution. Using the Bao'an District in Shenzhen, China, a typical rapid urbanization area, as the study area and land-use change maps from 1988 to 2014 that were obtained by remote sensing, the contributions of different land-use types to NPS pollutant production were assessed with a localized long-term hydrologic impact assessment (L-THIA) model. The results show that the non-point source pollution load changed significantly both in terms of magnitude and spatial distribution. The loads of chemical oxygen demand, total suspended substances, total nitrogen and total phosphorus were affected by the interactions between event mean concentration and the magnitude of changes in land-use acreages and the spatial distribution. From 1988 to 2014, the loads of chemical oxygen demand, suspended substances and total phosphorus showed clearly increasing trends with rates of 132.48 %, 32.52 % and 38.76 %, respectively, while the load of total nitrogen decreased by 71.52 %. The immigrant population ratio was selected as an indicator to represent the level of rapid urbanization and industrialization in the study area, and a comparison analysis of the indicator with the four non-point source loads demonstrated that the chemical oxygen demand, total phosphorus and total nitrogen loads are linearly related to the immigrant population ratio. The results provide useful information for environmental improvement and city management in the study area.

  9. Delineating complex spatiotemporal distribution of earthquake aftershocks: an improved Source-Scanning Algorithm

    NASA Astrophysics Data System (ADS)

    Liao, Yen-Che; Kao, Honn; Rosenberger, Andreas; Hsu, Shu-Kun; Huang, Bor-Shouh

    2012-06-01

    Conventional earthquake location methods depend critically on the correct identification of seismic phases and their arrival times from seismograms. Accurate phase picking is particularly difficult for aftershocks that occur closely in time and space, mostly because of the ambiguity of correlating the same phase at different stations. In this study, we introduce an improved Source-Scanning Algorithm (ISSA) for the purpose of delineating the complex distribution of aftershocks without time-consuming and labour-intensive phase-picking procedures. The improvements include the application of a ground motion analyser to separate P and S waves, the automatic adjustment of time windows for 'brightness' calculation based on the scanning resolution and a modified brightness function to combine constraints from multiple phases. Synthetic experiments simulating a challenging scenario are conducted to demonstrate the robustness of the ISSA. The method is applied to a field data set selected from the ocean-bottom-seismograph records of an offshore aftershock sequence southwest of Taiwan. Although visual inspection of the seismograms is ambiguous, our ISSA analysis clearly delineates two events that can best explain the observed waveform pattern.

  10. Incorporation of Complex Hydrological and Socio-economic Factors for Non-point Source Pollution Control: A Case Study at the Yincungang Canal, the Lake Tai Basin of China

    NASA Astrophysics Data System (ADS)

    Yang, X.; Luo, X.; Zheng, Z.

    2012-04-01

    It is increasingly realized that non-point pollution sources contribute significantly to water environment deterioration in China. Compared to developed countries, non-point source pollution in China has the unique characteristics of strong intensity and composition complexity due to its special socioeconomic conditions. First, more than 50% of its 1.3 billion people are rural. Sewage from the majority of the rural households is discharged either without or only with minimal treatment. The large amount of erratic rural sewage discharge is a significant source of water pollution. Second, China is plagued with serious agricultural pollution due to widespread improper application of fertilizers and pesticides. Finally, there lack sufficient disposal and recycling of rural wastes such as livestock manure and crop straws. Pollutant loads from various sources have far exceeded environmental assimilation capacity in many parts of China. The Lake Tai basin is one typical example. Lake Tai is the third largest freshwater lake in China. The basin is located in the highly developed and densely populated Yangtze River Delta. While accounting for 0.4% of its land area and 2.9% of its population, the Lake Tai basin generates more than 14% of China's Gross Domestic Production (GDP), and the basin's GDP per capita is 3.5 times as much as the state average. Lake Tai is vital to the basin's socio-economic development, providing multiple services including water supply for municipal, industrial, and agricultural needs, navigation, flood control, fishery, and tourism. Unfortunately, accompanied with the fast economic development is serious water environment deterioration in the Lake Tai basin. The lake is becoming increasingly eutrophied and has frequently suffered from cyanobacterial blooms in recent decades. Chinese government has made tremendous investment in order to mitigate water pollution conditions in the basin. Nevertheless, the trend of deteriorating water quality has yet to

  11. Evaluation of Land Use, Land Management and Soil Conservation Strategies to Reduce Non-Point Source Pollution Loads in the Three Gorges Region, China.

    PubMed

    Strehmel, Alexander; Schmalz, Britta; Fohrer, Nicola

    2016-11-01

    The construction of the Three Gorges Dam in China and the subsequent impoundment of the Yangtze River have induced a major land use change in the Three Gorges Reservoir Region, which fosters increased inputs of sediment and nutrients from diffuse sources into the water bodies. Several government programs have been implemented to mitigate high sediment and nutrient loads to the reservoir. However, institutional weaknesses and a focus on economic development have so far widely counteracted the effectiveness of these programs. In this study, the eco-hydrological model soil and water assessment tool is used to assess the effects of changes in fertilizer amounts and the conditions of bench terraces in the Xiangxi catchment in the Three Gorges Reservoir Region on diffuse matter releases. With this, the study aims at identifying efficient management measures, which should have priority. The results show that a reduction of fertilizer amounts cannot reduce phosphorus loads considerably without inhibiting crop productivity. The condition of terraces in the catchment has a strong impact on soil erosion and phosphorus releases from agricultural areas. Hence, if economically feasible, programmes focusing on the construction and maintenance of terraces in the region should be implemented. Additionally, intercropping on corn fields as well as more efficient fertilization schemes for agricultural land were identified as potential instruments to reduce diffuse matter loads further. While the study was carried out in the Three Gorges Region, its findings may also beneficial for the reduction of water pollution in other mountainous areas with strong agricultural use.

  12. Evaluation of Land Use, Land Management and Soil Conservation Strategies to Reduce Non-Point Source Pollution Loads in the Three Gorges Region, China

    NASA Astrophysics Data System (ADS)

    Strehmel, Alexander; Schmalz, Britta; Fohrer, Nicola

    2016-11-01

    The construction of the Three Gorges Dam in China and the subsequent impoundment of the Yangtze River have induced a major land use change in the Three Gorges Reservoir Region, which fosters increased inputs of sediment and nutrients from diffuse sources into the water bodies. Several government programs have been implemented to mitigate high sediment and nutrient loads to the reservoir. However, institutional weaknesses and a focus on economic development have so far widely counteracted the effectiveness of these programs. In this study, the eco-hydrological model soil and water assessment tool is used to assess the effects of changes in fertilizer amounts and the conditions of bench terraces in the Xiangxi catchment in the Three Gorges Reservoir Region on diffuse matter releases. With this, the study aims at identifying efficient management measures, which should have priority. The results show that a reduction of fertilizer amounts cannot reduce phosphorus loads considerably without inhibiting crop productivity. The condition of terraces in the catchment has a strong impact on soil erosion and phosphorus releases from agricultural areas. Hence, if economically feasible, programmes focusing on the construction and maintenance of terraces in the region should be implemented. Additionally, intercropping on corn fields as well as more efficient fertilization schemes for agricultural land were identified as potential instruments to reduce diffuse matter loads further. While the study was carried out in the Three Gorges Region, its findings may also beneficial for the reduction of water pollution in other mountainous areas with strong agricultural use.

  13. Environmental Education: Non-point Source Pollution

    EPA Pesticide Factsheets

    This activity is designed to demonstrate to students what an average storm drain collects during a rainfall event and how the water from storm drains can impact the water quality and aquatic environments of local streams, rivers, and bays.

  14. An ecological genetic delineation of local seed-source provenance for ecological restoration

    PubMed Central

    Krauss, Siegfried L; Sinclair, Elizabeth A; Bussell, John D; Hobbs, Richard J

    2013-01-01

    An increasingly important practical application of the analysis of spatial genetic structure within plant species is to help define the extent of local provenance seed collection zones that minimize negative impacts in ecological restoration programs. Here, we derive seed sourcing guidelines from a novel range-wide assessment of spatial genetic structure of 24 populations of Banksia menziesii (Proteaceae), a widely distributed Western Australian tree of significance in local ecological restoration programs. An analysis of molecular variance (AMOVA) of 100 amplified fragment length polymorphism (AFLP) markers revealed significant genetic differentiation among populations (ΦPT = 0.18). Pairwise population genetic dissimilarity was correlated with geographic distance, but not environmental distance derived from 15 climate variables, suggesting overall neutrality of these markers with regard to these climate variables. Nevertheless, Bayesian outlier analysis identified four markers potentially under selection, although these were not correlated with the climate variables. We calculated a global R-statistic using analysis of similarities (ANOSIM) to test the statistical significance of population differentiation and to infer a threshold seed collection zone distance of ∼60 km (all markers) and 100 km (outlier markers) when genetic distance was regressed against geographic distance. Population pairs separated by >60 km were, on average, twice as likely to be significantly genetically differentiated than population pairs separated by <60 km, suggesting that habitat-matched sites within a 30-km radius around a restoration site genetically defines a local provenance seed collection zone for B. menziesii. Our approach is a novel probability-based practical solution for the delineation of a local seed collection zone to minimize negative genetic impacts in ecological restoration. PMID:23919158

  15. Delineating Fecal Contaminant Sources and Travel Times in a Karst Groundwater Basin, Inner Bluegrass Region, Kentucky

    NASA Astrophysics Data System (ADS)

    Ward, J. W.; Reed, T. M.; Fryar, A. E.; Brion, G. M.

    2006-12-01

    Because of preferential flowpaths via features such as sinkholes and conduits, karst aquifers are susceptible to non-point-source pollution from agricultural and urban drainage. With many karst aquifers being drinking- water sources, pathogens are contaminants of public health concern. Monitoring of microbial parameters (total coliforms [TC], atypical colonies [AC] and fecal coliform bacteria [FC]) transpired biweekly from December 2002 March 2004 and weekly from February October 2005 at Blue Hole Spring, which drains outlying farm lands and the town of Versailles in the Inner Bluegrass Region of Kentucky. Physicochemical parameters (discharge, temperature, specific conductance, and pH) were measured continuously during the entire period. The AC/TC ratio, which had been employed only in surface water-quality studies, was used with FC counts, precipitation and discharge data to determine sources of fecal loading to ground water as result of land-use practices. An AC/TC ratio < 10 demonstrates fresh input of fecal matter, while a larger ratio can represent a variety of occurrences, including aged fecal material input and/or lack of nutrient input into the system. AC/TC ratio data in the 2002 04 dataset behaved similarly to surface waters, with ratios > 10 during dry periods and < 10 during wet periods, while the 2005 data demonstrated a very irregular pattern. The difference in these two data sets indicated a compositional change within the groundwater basin between the two sampling periods, perhaps as a result of construction at a sewage treatment plant adjoining the spring. Solute (rhodamine WT fluorescent dye and bromide) and particle (1-μm diameter fluorescent latex microspheres) tracer tests were conducted during summer 2006 to examine contaminant mobility within the system under base-flow and storm-flow conditions. Rainfall was limited prior to the base-flow trace, totaling 0.025 cm within 2 weeks prior to the slug injection. Base-flow discharge averaged 400 m

  16. Using analytic element models to delineate drinking water source protection areas.

    PubMed

    Raymond, Heather A; Bondoc, Michael; McGinnis, John; Metropulos, Kathy; Heider, Pat; Reed, Allison; Saines, Steve

    2006-01-01

    Since 1999, Ohio EPA hydrogeologists have used two analytic element models (AEMs), the proprietary software GFLOW and U.S. EPA's WhAEM, to delineate protection areas for 535 public water systems. Both models now use the GFLOW2001 solution engine, integrate well with Geographic Information System (GIS) technology, have a user-friendly graphical interface, are capable of simulating a variety of complex hydrogeologic settings, and do not rely upon a model grid. These features simplify the modeling process and enable AEMs to bridge the gap between existing simplistic delineation methods and more complex numerical models. Ohio EPA hydrogeologists demonstrated that WhAEM2000 and GFLOW2000 were capable of producing capture zones similar to more widely accepted models by applying the AEMs to eight sites that had been previously delineated using other methods. After the Ohio EPA delineated protection areas using AEMs, more simplistic delineation methods used by other states (volumetric equation and arbitrary fixed radii) were applied to the same water systems to compare the differences between various methods. GIS software and two-tailed paired t-tests were used to quantify the differences in protection areas and analyze the data. The results of this analysis demonstrate that AEMs typically produce significantly different protection areas than the most simplistic delineation methods, in terms of total area and shape. If the volumetric equation had been used instead of AEMs, Ohio would not have protected 265 km2 of critical upgradient area and would have overprotected 269 km2 of primarily downgradient land. Since an increasing number of land-use restrictions are being tied to drinking water protection areas, this analysis has broad policy implications.

  17. Impacts of climate and land-use changes on the migration of non-point source nitrogen and phosphorus during rainfall-runoff in the Jialing River Watershed, China

    NASA Astrophysics Data System (ADS)

    Wu, Lei; Long, Tian-yu; Liu, Xia; Guo, Jin-song

    2012-12-01

    SummaryThe loss of nitrogen and phosphorus via non-point source (NPS) pollution in the Jialing River Watershed has become the main pollution sources of river waters in the Three Gorges reservoir area in the past decades, while climatic conditions and human activities directly affect changes of rainfall-runoff and land use types which are closely related to NPS pollution. This study is to assess the impact of climate change on hydrological behavior considering future land-use types and rural residential area and their propagation to NPS pollution loads. An integrated pollution load model composed of regional climate, the Semi-distributed Land Use based Runoff Processes (SLURPs) hydrological model and the improved export coefficient approach within a single framework was explored and developed to assess impacts of climate and land-use changes on NPS pollution load. Climate data for the Special Report on Emissions Scenarios (SRESs) future scenario B2 from Met Office Hadley center were generated and used as the input data for the runoff and NPS load evaluation of the Jialing River Watershed and the Markov process was used to forecast changes of land use types, respectively. Simulations of present and future regional NPS pollution from land use, livestock and poultry breeding, and agricultural population over the Jialing River Watershed were performed to investigate the potential impacts of global climate change on river water quality using the established model. Results demonstrate that: (1) Annual pollution load would obviously change due to variations of runoff and livestock and poultry breeding, the largest growth months in one year for total nitrogen (TN) and total phosphorus (TP) load are both in June, which is in accordance with changes of rainfall amount. (2) The impacts of global climate change on pollution load are relatively greater when compared to the impacts of future livestock and poultry breeding increase or agricultural population reduction; the effects

  18. A Source Water Assessment of the INEEL: Conjunctive Delineation of a Large Scale Area

    SciTech Connect

    Sehlke, Gerald; Andersen, Bradley Don

    2003-01-01

    Presently, the INEEL operates and monitors 12 Public Water Systems that pump water from 22 wells for at the Site (Table 1). The source of water for each of these facilities is the eastern Snake River Plain aquifer. Because the INEEL operates Public Water Systems, it is required to conduct source water assessments for those facilities and to develop a Source Water Management Program.

  19. Watershed delineation and nitrogen source analysis for Bayou Chico, an urban watershed in northwest Florida

    EPA Science Inventory

    Nutrient pollution in stormwater runoff from urbanized areas contributes to water quality degradation in streams and receiving waterbodies. Agriculture, population growth, and industrial activities are significant sources of nitrogen inputs for surface waters. Increased nitrogen ...

  20. Geographically Sourcing Cocaine's Origin - Delineation of the Nineteen Major Coca Growing Regions in South America.

    PubMed

    Mallette, Jennifer R; Casale, John F; Jordan, James; Morello, David R; Beyer, Paul M

    2016-03-23

    Previously, geo-sourcing to five major coca growing regions within South America was accomplished. However, the expansion of coca cultivation throughout South America made sub-regional origin determinations increasingly difficult. The former methodology was recently enhanced with additional stable isotope analyses ((2)H and (18)O) to fully characterize cocaine due to the varying environmental conditions in which the coca was grown. An improved data analysis method was implemented with the combination of machine learning and multivariate statistical analysis methods to provide further partitioning between growing regions. Here, we show how the combination of trace cocaine alkaloids, stable isotopes, and multivariate statistical analyses can be used to classify illicit cocaine as originating from one of 19 growing regions within South America. The data obtained through this approach can be used to describe current coca cultivation and production trends, highlight trafficking routes, as well as identify new coca growing regions.

  1. Source identification and hazardous risk delineation of heavy metal contamination in Yanqi basin, northwest China.

    PubMed

    Mamat, Zulpiya; Yimit, Hamid; Ji, Rou Zi A; Eziz, Mamattursun

    2014-09-15

    A total of 469 surface soil samples were collected from the Yanqi basin in northwest China and evaluated for levels of ten heavy metals. Multivariate statistical analyses were used to study sources of and map the spatial distribution of heavy metals, as well as determine the relationship between land use types and soil source materials. It was found that: (1) the average amounts of ten heavy metals in the Yanqi basin were all below the national soil environmental quality standards of China (GB15618-1998), but the average amount of Cd, Hg, Mn, Ni, Pb, and Zn all exceeded the heavy metal background levels of soil in Xinjiang, China and exhibited accumulation. The ten heavy metals analyzed in this study can be categorized into four principal components as follows: Principal component 1 was Co, Cr, Mn, Ni, and Zn, and principal component 3 was As and Cu. Both of these originated from a natural geological background. Principal component 2 consisted of Cd and Pb and originated from industrial, agricultural and transportation influences. Principal component 4 consisted of Hg and was due to industrial influences. Our study found that Pb and Zn were a large part in the principal components 1 and 3 and were influenced by a combination of geologic background and human activity. (2) Heavy metals Cd and Hg were at high levels in construction land and farmland, while Co, Cr, Cu, Mn, and Ni were significantly higher in lacustrine deposits than in sandy shale from weathered material, coarse crystalline rock weathered material, and diluvial material. The land use types correlated significantly with the accumulation of Cd and Hg, and the soil parent material was the major factor for the accumulation of As, Co, Cr, Cu, Mn, and Ni. (3) The single element, element integration and the corresponding principal component presented similar spatial patterns of hazardous risk. Following comprehensive assessment of all elements, the high risk regions were found to be located in densely

  2. Cadmium ecophysiology in seven stonefly (Plecoptera) species: Delineating sources and estimating susceptibility

    USGS Publications Warehouse

    Martin, C.A.; Luoma, S.N.; Cain, D.J.; Buchwalter, D.B.

    2007-01-01

    A major challenge in ecotoxicology lies in generating data under experimental conditions that are relevant to understanding contaminant effects in nature. Biodynamic modeling combines species-specific physiological traits to make predictions of metal bioaccumulation that fare well when tested in the field. We generated biodynamic models for seven predatory stonefly (Plecoptera) species representing the families Perlidae (5) and Perlodidae (2). Each taxon was exposed to cadmium independently via diet and via solution. Species varied approximately 2.6 fold in predicted steady-state cadmium concentrations. Diet was the predominant source of accumulated cadmium in five of the seven species and averaged 53.2 ?? 9.6% and 90.2 ?? 3.7% of net Cd accumulation in perlids and perlodids, respectively. Differences in Cd bioaccumulation between the two families were largely driven by differences in dissolved accumulation rates, which were considerably slower in perlodids than in perlids. We further examined the subcellular compartmentalization of Cd accumulated from independent aqueous and dietary exposures. Predicted steady-state concentrations were modified to only consider Cd accumulated in metal-sensitive subcellular compartments. These values ranged 5.3 fold. We discuss this variability within a phylogenetic context and its implications for bioassessment. ?? 2007 American Chemical Society.

  3. Delineation of Piceance Basin basement structures using multiple source data: Implications for fractured reservoir exploration

    SciTech Connect

    Hoak, T.E.; Klawitter, A.L.

    1995-10-01

    Fractured production trends in Piceance Basin Cretaceous-age Mesaverde Group gas reservoirs are controlled by subsurface structures. Because many of the subsurface structures are controlled by basement fault trends, a new interpretation of basement structure was performed using an integrated interpretation of Landsat Thematic Mapper (TM), side-looking airborne radar (SLAR), high altitude, false color aerial photography, gas and water production data, high-resolution aeromagnetic data, subsurface geologic information, and surficial fracture maps. This new interpretation demonstrates the importance of basement structures on the nucleation and development of overlying structures and associated natural fractures in the hydrocarbon-bearing section. Grand Valley, Parachute, Rulison, Plateau, Shire Gulch, White River Dome, Divide Creek and Wolf Creek fields all produce gas from fractured tight gas sand and coal reservoirs within the Mesaverde Group. Tectonic fracturing involving basement structures is responsible for development of permeability allowing economic production from the reservoirs. In this context, the significance of detecting natural fractures using the intergrated fracture detection technique is critical to developing tight gas resources. Integration of data from widely-available, relatively inexpensive sources such as high-resolution aeromagnetics, remote sensing imagery analysis and regional geologic syntheses provide diagnostic data sets to incorporate into an overall methodology for targeting fractured reservoirs. The ultimate application of this methodology is the development and calibration of a potent exploration tool to predict subsurface fractured reservoirs, and target areas for exploration drilling, and infill and step-out development programs.

  4. SOURCE WATER AREA DELINEATION OF PUBLIC WATER SUPPLY WELLS USING WHAEM2000. INTERNATIONAL GROUND WATER MODELING CENTER NEWSLETTER, V.19(1):4

    EPA Science Inventory

    WhAEM2000 is computer program that solves steady state ground-water flow and advective streamlines in homogeneous, single layer aquifers. The program was designed for capture zone delineation in support of protection of the source water area surrounding public water supply well...

  5. Controlled-source electromagnetic and seismic delineation of subseafloor fluid flow structures in a gas hydrate province, offshore Norway

    NASA Astrophysics Data System (ADS)

    Attias, Eric; Weitemeyer, Karen; Minshull, Tim A.; Best, Angus I.; Sinha, Martin; Jegen-Kulcsar, Marion; Hölz, Sebastian; Berndt, Christian

    2016-08-01

    Deep sea pockmarks underlain by chimney-like or pipe structures that contain methane hydrate are abundant along the Norwegian continental margin. In such hydrate provinces the interaction between hydrate formation and fluid flow has significance for benthic ecosystems and possibly climate change. The Nyegga region, situated on the western Norwegian continental slope, is characterized by an extensive pockmark field known to accommodate substantial methane gas hydrate deposits. The aim of this study is to detect and delineate both the gas hydrate and free gas reservoirs at one of Nyegga's pockmarks. In 2012, a marine controlled-source electromagnetic (CSEM) survey was performed at a pockmark in this region, where high-resolution 3-D seismic data were previously collected in 2006. 2-D CSEM inversions were computed using the data acquired by ocean bottom electrical field receivers. Our results, derived from unconstrained and seismically constrained CSEM inversions, suggest the presence of two distinctive resistivity anomalies beneath the pockmark: a shallow vertical anomaly at the underlying pipe structure, likely due to gas hydrate accumulation, and a laterally extensive anomaly attributed to a free gas zone below the base of the gas hydrate stability zone. This work contributes to a robust characterization of gas hydrate deposits within subseafloor fluid flow pipe structures.

  6. Delineation of the sources and sinks of heterogeneously distributed methane in the Pearl River and its estuary

    NASA Astrophysics Data System (ADS)

    Wang, J.; Xie, W.; Wei, Y.; Zhang, C.

    2013-12-01

    Methane in low temperature environments is mostly produced by methanogens. Sharp decrease in methane concentration has been observed from freshwater to marine water in coastal regions. The goal of this study was to delineate the sources and sinks of methane from the lower Pearl River (including, North, West, and East segments) and its estuary along a salinity gradient (0.0 % to 3.4%). Methane concentration in lower Pearl River ranged from 50.1 to 10578 nmol L-1 in the winter (average = 565.5 × 1464.9 nmol L-1) and from 38.4 to 974.1 nmol L-1 in the summer (average = 179.6 × 165.7 nmol L-1). In the estuary, however, methane concentration was 5-10 folds lower in winter and 3-8 folds lower in summer. The sea-to-air methane flux was also much higher in the fresh water (3159.6 umol/d.m2) than in the estuary (528.1 umol/d.m2). Abnormally high methane concentrations and methane flux in the East Pearl River appear to be associated with effluents of industrial or municipal wastes. DNA sequencing of the archaeal 16S rRNA gene indicates predominance of methanogens in the freshwater and their disappearance in the estuary. This is supported by the archaeal lipoid analysis, which showed the predominance of archaeol and caldarchaeol that characterize the methanogens. It is unknown, however, how aerobic (bacteria) and anerobic (archaea) methanotrophs may be involved in the oxidation of methane in the estuary environment where methane consumption is apparently occurring.

  7. Inferring non-point pollution from land cover analysis

    NASA Astrophysics Data System (ADS)

    Hyde, Richard F.

    Best Management Practices (BMP's) in farming were found to significantly reduce agricultural non-point water pollution in Central Indiana. Through the implementation of systems of conservation tillage practices and structural measures at the farm level, reductions in runoff were achieved, thereby minimizing erosion and subsequent sedimentation and pollution of the surface water system. These conclusions resulted from a three and one-half year study entitled, ``The Indiana Heartland Model Implementation Project'' administered by the Indiana Heartland Coordinating Commission, involving cooperation and coordination of farmers, citizens, and a multi-agency, multi-disciplinary team comprised of four universities and numerous governmental agencies. The U.S. Environmental Protection Agency funded research, while the U.S. Department of Agriculture provided cost share monies for BMP implementation. A comprehensive geographically encoded computer-aided data base was constructed which included information on land cover, elevation, slope, aspect, soils, etc. Land cover map files were compiled through remote sensing including Landsat MSS digital data and low altitude color infrared aerial photography sources. This digital data base was suited for spatial and statistical analyses and transferred easily as input to Purdue University's ANSWERS Model for further watershed assessment. The ANSWERS Model is a distributed deterministic model which simulates the monitored reaction of subwatersheds to actual storm events. Through this model inferences were made as to the expected water quality improvements, given BMP's were implemented at critical areas for erosion throughout both watersheds.

  8. Delineation of water sources for public-supply wells in three fractured-bedrock aquifer systems in Massachusetts

    USGS Publications Warehouse

    Lyford, Forest P.; Carlson, Carl S.; Hansen, Bruce P.

    2003-01-01

    Fractured-bedrock aquifer systems in West Newbury, Maynard, and Paxton, Massachusetts, were studied to advance methods of data collection and analysis for delineating contributing areas to public-supply wells completed in fractured rock and for determining the effects of pumping on streams and wetlands. Contributing areas, as defined for this study, include all areas through which ground water flows from recharge areas to wells. In West Newbury, exploratory public-supply wells at two locations were completed in phyllite of the Eliot Formation. Aquifer testing indicated that subhorizontal and steeply dipping fractures that parallel two sets of foliation form elongated transmissive zones in the bedrock aquifer near the two well locations and also form a vertical hydraulic connection to surficial materials consisting of till at one location and marine clay at the other location. Recharge to bedrock is largely through a thin veneer of till over bedrock, but leakage through thick drumlin tills also recharges bedrock. Simulated contributing areas for the three supply wells pumped at a combined rate of 251 gallons per minute encompass about 1.3 square miles and extend to ground-water divides within most of a subbasin of the Artichoke River. Pumping likely would reduce streamflow in the Artichoke River subbasin by approximately the pumping rate. Pumping is likely to affect wetland areas underlain by till near the wells because of the vertical hydraulic connection to surficial materials. In Maynard, three exploratory public-supply wells were completed in coarse-grained schist of the Nashoba Formation. Aquifer testing indicated that a dense network of fractures in bedrock forms a laterally extensive transmissive zone in bedrock that is well connected vertically to surficial materials consisting of sandy till, lacustrine silts, sand and gravel, and wetland deposits. The simulated contributing area for the three supply wells pumped at a combined rate of 780 gallons per minute

  9. Geographically Sourcing Cocaine’s Origin – Delineation of the Nineteen Major Coca Growing Regions in South America

    NASA Astrophysics Data System (ADS)

    Mallette, Jennifer R.; Casale, John F.; Jordan, James; Morello, David R.; Beyer, Paul M.

    2016-03-01

    Previously, geo-sourcing to five major coca growing regions within South America was accomplished. However, the expansion of coca cultivation throughout South America made sub-regional origin determinations increasingly difficult. The former methodology was recently enhanced with additional stable isotope analyses (2H and 18O) to fully characterize cocaine due to the varying environmental conditions in which the coca was grown. An improved data analysis method was implemented with the combination of machine learning and multivariate statistical analysis methods to provide further partitioning between growing regions. Here, we show how the combination of trace cocaine alkaloids, stable isotopes, and multivariate statistical analyses can be used to classify illicit cocaine as originating from one of 19 growing regions within South America. The data obtained through this approach can be used to describe current coca cultivation and production trends, highlight trafficking routes, as well as identify new coca growing regions.

  10. Geographically Sourcing Cocaine’s Origin – Delineation of the Nineteen Major Coca Growing Regions in South America

    PubMed Central

    Mallette, Jennifer R.; Casale, John F.; Jordan, James; Morello, David R.; Beyer, Paul M.

    2016-01-01

    Previously, geo-sourcing to five major coca growing regions within South America was accomplished. However, the expansion of coca cultivation throughout South America made sub-regional origin determinations increasingly difficult. The former methodology was recently enhanced with additional stable isotope analyses (2H and 18O) to fully characterize cocaine due to the varying environmental conditions in which the coca was grown. An improved data analysis method was implemented with the combination of machine learning and multivariate statistical analysis methods to provide further partitioning between growing regions. Here, we show how the combination of trace cocaine alkaloids, stable isotopes, and multivariate statistical analyses can be used to classify illicit cocaine as originating from one of 19 growing regions within South America. The data obtained through this approach can be used to describe current coca cultivation and production trends, highlight trafficking routes, as well as identify new coca growing regions. PMID:27006288

  11. Automated Crater Delineation

    NASA Astrophysics Data System (ADS)

    Marques, J. S.; Pina, P.

    2015-05-01

    An algorithm to delineate impact craters based on Edge Maps and Dynamic Programming is presented. The global performance obtained on 1045 craters from Mars (5 m to about 200 km in diameter), achieved 96% of correct contour delineations.

  12. Evaluating Urbanization Impacts from Non-Point Stormwater Runoff using Geospatial Analysis

    NASA Astrophysics Data System (ADS)

    Zivkovich, B. R.; Mays, D. C.

    2015-12-01

    Sediments, nutrients and other chemical impairments caused by urbanization continue to deteriorate natural ecosystem processes, resulting in the current degraded state of urban surface waters. Understanding non-point source impacts on these natural ecosystems has become a prevalent topic in sustainable urban infrastructure design as efforts to restore the urban hydrologic regime continue to drive engineers, planners, and environmentalists to develop optimal design practices for rapidly expanding built environments. To best understand how and where these impairments are received, the U.S. Environmental Protection Agency and other organizations have adopted urban runoff programs to identify contributions from non-point sources. This presentation provides a geospatial analysis method for identifying non-point source watersheds, and associated sub-basins, that contribute the highest loads of pollutants to receiving urban streams and lakes. This method, using a form of linear matrix inversion, is an area-averaged weighting method for non-point pollutants that corresponds to a geospatial land cover analysis. This two-phase analysis can be used to aid all parties in understanding how different land use types affect urban stream systems and processes. Optimal locations for water quality features (i.e., best management practices) can be evaluated in order to reduce, capture, and treat stormwater runoff as close to the source as possible. These best management practices have the ability to operate most effectively when located properly, because their ability to act as a minor treatment and prevention system is of great important for the restoration of the urban hydrologic regime.

  13. Delineation of a wellhead protection zone and determination of flowpaths from potential groundwater contaminant source areas at Camp Ripley, Little Falls, Minnesota.

    SciTech Connect

    Quinn, J. J.; Environmental Science Division

    2006-12-22

    Groundwater at Camp Ripley, Minnesota, is recharged both on post and off site and discharged to rivers, wetlands, and pumping wells. The subsurface geologic materials have a wide range of permeabilities and are arranged in a complex fashion as a result of the region's multiple glacial advances. Correlation of individual glacial geologic units is difficult, even between nearby boreholes, because of the heterogeneities in the subsurface. This report documents the creation of a numerical model of groundwater flow for Camp Ripley and hydrologically related areas to the west and southwest. The model relies on a hydrogeological conceptual model built on the findings of a University of Minnesota-Duluth drilling and sampling program conducted in 2001. Because of the site's stratigraphic complexity, a geostatistical approach was taken to handle the uncertainty of the subsurface correlation. The U.S. Geological Survey's MODFLOW code was used to create the steady-state model, which includes input data from a variety of sources and is calibrated to water levels in monitoring wells across much of the site. This model was used for several applications. Wellhead protection zones were delineated for on-site production wells H, L, and N. The zones were determined on the basis of a probabilistic assessment of the groundwater captured by these wells; the assessment, in turn, had been based on multiple realizations of the study area's stratigraphy and groundwater flowfield. An additional application of the model was for estimating flowpaths and times of travel for groundwater at Camp Ripley's range areas and waste management facilities.

  14. Comparative study of methods for WHPA delineation.

    PubMed

    Paradis, Daniel; Martel, Richard; Karanta, Gilbert; Lefebvre, René; Michaud, Yves; Therrien, René; Nastev, Miroslav

    2007-01-01

    Human activities, whether agricultural, industrial, commercial, or domestic, can contribute to ground water quality deterioration. In order to protect the ground water exploited by a production well, it is essential to develop a good knowledge of the flow system and to adequately delineate the area surrounding the well within which potential contamination sources should be managed. Many methods have been developed to delineate such a wellhead protection area (WHPA). The integration of more information on the geologic and hydrogeologic characteristics of the study area increases the precision of any given WHPA delineation method. From a practical point of view, the WHPA delineation methods allowing the simplest and least expensive integration of the available information should be favored. This paper presents a comparative study in which nine different WHPA delineation methods were applied to a well and a spring in an unconfined granular aquifer and to a well in a confined highly fractured rock aquifer. These methods range from simple approaches to complex computer models. Hydrogeological mapping and numerical modeling with MODFLOW-MODPATH were used as reference methods to respectively compare the delineation of the zone of contribution and the zone of travel obtained from the various WHPA methods. Although applied to simple ground water flow systems, these methods provided a relatively wide range of results. To allow a realistic delineation of the WHPA in aquifers of variable geometry, a WHPA delineation method should ensure a water balance and include observed or calculated regional flow characteristics.

  15. [GIS and L-THIA based analysis on variations of non-point pollution in the Guanlan River watershed, Shenzhen].

    PubMed

    Bai, Feng-jiao; Li, Tian-hong

    2012-08-01

    In order to reveal the influence of land use change, on the non-point source pollution load during the rapid urbanization process in the Guanlan River watershed, Shenzhen, Guangdong, with the support of GIS, L-THIA model was used to analyze the changes in spatial distribution of non-point source pollution load in the river watershed from 1996 to 2008. The parameters in L-THIA model were revised according to the environmental conditions of the study region. The results showed that during the urbanization from 1996 to 2008, the load of major pollutants, namely TN, TP and COD, showed an obviously increasing trend with increase rates being 62.78%, 59.73% and 55.40%, respectively, and the distribution of areas with high pollution load was expanding along the river and the main roads, and then connected into large areas. The total load of SS was decreased by 7.59%. This was caused by the reduction of land for development, which was the land use pattern with high SS output. Therefore, in order to control the non-point pollution effectively, the Guanlan River watershed could be divided into four pollution control areas according to the distribution of pollution load and different land use patterns. The results of this research would provide scientific references for non-point source pollution control in the Guanlan River watershed.

  16. Anthropogenic point and non-point nitrogen inputs into Huai River Basin and their impacts on riverine ammonia-nitrogen flux

    NASA Astrophysics Data System (ADS)

    Zhang, W. S.; Swaney, D. P.; Li, X. Y.; Hong, B.; Howarth, R. W.; Ding, S. H.

    2015-02-01

    This study provides a new approach to estimate both anthropogenic non-point and point nitrogen (N) inputs to the landscape, and determines their impacts on riverine ammonia-nitrogen (AN) flux, providing a foundation for further exploration of anthropogenic effects on N pollution. Our study site is Huai River Basin of China, a watershed with one of the highest levels of N input in the world. Multi-year average (2003-2010) inputs of N to the watershed are 27 200 ± 1100 kg N km-2 yr-1. Non-point sources comprised about 98% of total N input and only 2% of inputs are directly added to the aquatic ecosystem as point sources. Fertilizer application was the largest non-point source of new N to the Huai River Basin (69% of net anthropogenic N inputs), followed by atmospheric deposition (20%), N fixation in croplands (7%), and N content of imported food and feed (2%). High N inputs showed impacts on riverine AN flux: fertilizer application, point N input and atmospheric N deposition were proved as more direct sources to riverine AN flux. Modes of N delivery and losses associated with biological denitrification in rivers, water consumption, interception by dams influenced the extent of export of riverine AN flux from N sources. Our findings highlight the importance of anthropogenic N inputs from point and non-point sources in heavily polluted watersheds, and provide some implications for AN prediction and management.

  17. Use of major ion and stable isotope geochemistry to delineate natural and anthropogenic sources of nitrate and sulfate in the Kettle River Basin, British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Harker, Leslie; Hutcheon, Ian; Mayer, Bernhard

    2015-11-01

    The Kettle River Basin in South central British Columbia (Canada) is under increasing anthropogenic pressures affecting both water quantity and quality of surface waters and aquifers. We investigated water quality and sources and processes influencing NO3- and SO42- in the Kettle River Basin using a combination of chemical and isotopic techniques. The dominant water type in the Kettle River Basin is Ca-HCO3 with surface waters having total dissolved solids (TDS) concentrations of < 115 mg/L and groundwaters having TDS values of up to 572 mg/L. Based on δ15NNO3andδ18ONO3 values and concentration data, NO3- in surface waters originates primarily from natural soil nitrification processes, with additional influences from anthropogenic activities, such as waste water effluents at sampling locations downstream from population centres. The source of NO3- in groundwater was predominantly nitrification of soil organic matter, although nitrate in a few groundwater samples originated from anthropogenic sources, including manure or septic systems. The dominant source of SO42- in surface water and groundwater samples was the natural oxidation of sulfide minerals. With increasing distance downstream, surface water δ18OSO4 values increase beyond the range of oxidation of sulfide minerals and into the range of soil and atmospheric-derived SO42- that is in part derived from anthropogenic emissions. Hence, we conclude that recent anthropogenic impacts have affected water quality only marginally at only few sites in the Kettle River Basin. The presented data will serve as an excellent baseline against which future impacts can be assessed.

  18. Improving the identification of hydrologically sensitive areas using LiDAR DEMs for the delineation and mitigation of critical source areas of diffuse pollution.

    PubMed

    Thomas, I A; Jordan, P; Mellander, P-E; Fenton, O; Shine, O; Ó hUallacháin, D; Creamer, R; McDonald, N T; Dunlop, P; Murphy, P N C

    2016-06-15

    Identifying critical source areas (CSAs) of diffuse pollution in agricultural catchments requires the accurate identification of hydrologically sensitive areas (HSAs) at highest propensity for generating surface runoff and transporting pollutants. A new GIS-based HSA Index is presented that improves the identification of HSAs at the sub-field scale by accounting for microtopographic controls. The Index is based on high resolution LiDAR data and a soil topographic index (STI) and also considers the hydrological disconnection of overland flow via topographic impediment from flow sinks. The HSA Index was applied to four intensive agricultural catchments (~7.5-12km(2)) with contrasting topography and soil types, and validated using rainfall-quickflow measurements during saturated winter storm events in 2009-2014. Total flow sink volume capacities ranged from 8298 to 59,584m(3) and caused 8.5-24.2% of overland-flow-generating-areas and 16.8-33.4% of catchment areas to become hydrologically disconnected from the open drainage channel network. HSA maps identified 'breakthrough points' and 'delivery points' along surface runoff pathways as vulnerable points where diffuse pollutants could be transported between fields or delivered to the open drainage network, respectively. Using these as proposed locations for targeting mitigation measures such as riparian buffer strips reduced potential costs compared to blanket implementation within an example agri-environment scheme by 66% and 91% over 1 and 5years respectively, which included LiDAR DEM acquisition costs. The HSA Index can be used as a hydrologically realistic transport component within a fully evolved sub-field scale CSA model, and can also be used to guide the implementation of 'treatment-train' mitigation strategies concurrent with sustainable agricultural intensification.

  19. 1. PHOTOCOPY OF HISTORIC DRAWING OF SHIP SECTION, UNKNOWN DELINEATOR ...

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

    1. PHOTOCOPY OF HISTORIC DRAWING OF SHIP SECTION, UNKNOWN DELINEATOR AND DATE, SOURCE: BISHOP MUSEUM, HONOLULU, HI. - Ship "Falls of Clyde", Hawaii Maritime Center,Pier 7, Honolulu, Honolulu County, HI

  20. [Adsorbed non-point source pollution load of Jialing River basin].

    PubMed

    Long, Tian-Yu; Li, Ji-Cheng; Liu, La-Mei

    2008-07-01

    Based on the American Universal Soil Loss Equation, focused on the two main factors that are hydrology condition and land management practice which can influence the soil loss in the watershed change yearly, and took into account the sediment transport process which can effect the soil loss differ spatially, a new sediment load evaluation method was put forward which can reflect the yearly change process of soil loss. Took Jialing River basin as a research example and validated the new evaluation method. Furthermore, according to the correlation between the sediment load and adsorbed nitrogen and phosphorus pollution load, established a yearly load evaluation model of the adsorbed nitrogen and phosphorus pollution. By virtue of the geographical information technology, the yearly load and spatial distribution of the adsorbed nitrogen and phosphorus pollution due to soil erosion in the Jialing River basin from 1990 to 2005 have been studied by the established model. The results show that adsorbed phase of nitrogen and phosphorus pollution are quite seriously in the subbasin of Bailong River and Xihanshui River. In recent years, adsorbed nitrogen and phosphorus pollution loads have declined year by year because of the conservation practices of soil and water in this basin. The average loads of adsorbed nitrogen and phosphorus pollution are 34 423 t/a and 1 848 t/a respectively in the past five years, which have reduced by about 60% from 1990.

  1. Watershed Management Tool for Selection and Spacial Allocation of Non-Point Source Pollution Control Practices

    EPA Science Inventory

    Distributed-parameter watershed models are often utilized for evaluating the effectiveness of sediment and nutrient abatement strategies through the traditional {calibrate→ validate→ predict} approach. The applicability of the method is limited due to modeling approximations. In ...

  2. In-situ treatment of non-point source pollution part 1: Concepts and chemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The loss of nutrients, particularly phosphorus (P), in agricultural and urban/suburban drainage waters is a priority conservation concern. Although several best management practices are effective in preventing particulate P losses to surface waters, they are less effective on dissolved P losses. Op...

  3. Non-point source pesticide pollution in CEAP watersheds - controlling factors and mitigation strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For more than 70 years, crop production in the USA has depended heavily on synthetic chemical pesticides for weed, insect, and disease management. These products continue to be critical components of pest management programs that sustain food and fiber production and protect public health, homes an...

  4. Application of Potential Non-Point Pollution Index For An Urban Watershed: Istanbul, Kucukcekmece Lagoon

    NASA Astrophysics Data System (ADS)

    Musaoglu, N.; Dikerler, T.; Seker, D. Z.; Ustun, B.

    2011-12-01

    Istanbul is a major city with more than 15 million population and limited water resources. Besides, its urbanized area has been rapidly expanding for more than 30 years. Küçükçekmece Lagoon, as a potential RAMSAR site with its rich natural diversity and housing asset for birds, has been suffering from urbanization and industrial stress. With Sazlidere Dam constructed on the Lagoon's most important creek which supplies fresh water, Küçükçekmece Basin has almost 600 km2 wide area. Due to dam operation which cuts fresh water input down, water quality of the Küçükçekmece Lagoon has been deteriorating, as well as other antropogenic impacts. Potential non-point pollution index (or PNPI) is based on land use, soil and topographic data and aims to highlight the potentially polluting areas in a watershed. Denoting those areas, PNPI puts an assessment of the pressure exerted on the water bodies by different land uses. This index calculates different layers in order to represent run-off, land cover effect, and the distance of each polluting source (or pixels) in the study area. By the multiplication of those layers under GIS, a new data layer is produced showing the polluting potential of each pixel on the study area. For by Küçükçekmece Basin, Landsat ETM satellite images have been taken and its land use produced by unsupervised classification. Using this updated data, land use - land cover indicator has been calculated for the basin. Topography is another fact that is needed to produce both run-off indicator and distance indicator and it is generated by elevation data with 5m resolution. By integrating these indicator layers, PNPI analysis layer has been produced for Küçükçekmece Lagoon watershed.

  5. Controlled-release fertilizer (CRF): a green fertilizer for controlling non-point contamination in agriculture.

    PubMed

    Mao, Xiao-yun; Sun, Ke-jun; Wang, De-han; Liao, Zong-wen

    2005-01-01

    Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas (N2O) and eutrophication of water bodies. How to solve this problem has become a serious challenge, especially for China as its high ecological pressure. Controlled-release fertilizer(CRF) has been developed to minimize the contamination while keeping high yield and has become a green fertilizer for agriculture. Several CRFs made with special coating technology were used for testing the fertilizer effects in yield and environment through pot experiment and field trial. The result indicated that the CRFs had higher N use efficiency, thus reducing N loss through leaching and volatilization while keeping higher yields. Comparing with imported standard CRFs, the test on CRFs showed similar fertilizer effect but with much lower cost. CRFs application is becoming a new approach for minimizing non-point contamination in agriculture.

  6. Trophic status and assessment of non-point nutrient enrichment of Lake Crescent Olympic National Park

    USGS Publications Warehouse

    Boyle, Terence P.; Beeson, David R.

    1991-01-01

    A limited effort study was conducted in Lake Crescent, Olympic National Park to determine the trophic status and assess whether non-point nutrients were leaching into the lake and affecting biological resources. The concentration of chlorophyll a, total nitrogen concentration, and Secchi disk transparency used as parameters of the Trophic Status Index revealed that Lake Crescent in Olympic National Park was in the oligotrophic range. Evaluation of the nitrogen to phosphorous ration revealed that nitrogen was the nutrient limiting to overall lake productivity. Single species and community bioassays indicated that other nutrients, possibly iron, had some secondary control over community composition of the algal community. Assessment of six near-shore sites for the presence and effects of non-point nutrients revealed that La Poel Point which formerly was the site of a resort had slightly higher algal bioassay and periphyton response than the other sites. No conditions that would require immediate action by resource management of Olympic National Park were identified. The general recommendations for a long term lake monitoring plan are discussed.

  7. Mapping hazard from urban non-point pollution: a screening model to support sustainable urban drainage planning.

    PubMed

    Mitchell, Gordon

    2005-01-01

    Non-point sources of pollution are difficult to identify and control, and are one of the main reasons that urban rivers fail to reach the water quality objectives set for them. Whilst sustainable drainage systems (SuDS) are available to help combat this diffuse pollution, they are mostly installed in areas of new urban development. However, SuDS must also be installed in existing built areas if diffuse loadings are to be reduced. Advice on where best to locate SuDS within existing built areas is limited, hence a semi-distributed stochastic GIS-model was developed to map small-area basin-wide loadings of 18 key stormwater pollutants. Load maps are combined with information on surface water quality objectives to permit mapping of diffuse pollution hazard to beneficial uses of receiving waters. The model thus aids SuDS planning and strategic management of urban diffuse pollution. The identification of diffuse emission 'hot spots' within a water quality objectives framework is consistent with the 'combined' (risk assessment) approach to pollution control advocated by the EU Water Framework Directive.

  8. Polluted dust derived from long-range transport as a major end member of urban aerosols and its implication of non-point pollution in northern China.

    PubMed

    Yan, Y; Sun, Y B; Weiss, D; Liang, L J; Chen, H Y

    2015-02-15

    The contribution of polluted dust transported from local and distal sources remains poorly constrained due to their similar geophysical and geochemical properties. We sampled aerosols in three cities in northern China (Xi'an, Beijing, Xifeng) during the spring of 2009 to determine dust flux, magnetic susceptibility and elemental concentrations. Combining dust fluxes with wind speed and regional visibility records enabled to differentiate between dust transported from long range and derived from local sources, while the combination of magnetic susceptibility and enrichment factors (EF) of heavy metals (Pb, Zn) allowed to distinguish natural aerosols from polluted ones. Our results indicate that polluted dust from long-range transport became a major end member of urban dust aerosols. Human settlements as its potential sources were confirmed by a pollutant enriched regional dust event originating from populated areas to the south as inferred by back trajectory modeling, implying their non-point source nature of dust pollution.

  9. Delineating Contaminants and Transport Pathways Within a Coastal Watershed in Southeast Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coastal water quality decline due to point and non-point source pollution from terrestrial sources is a serious concern throughout the Caribbean basin and worldwide. Toxic and noxious algal blooms, declines in mangrove forests and seagrass meadows, depletion of fishery stocks, coral reef die-off, pu...

  10. A repeated-measures study of recreational water exposure, non-point source pollution, and risk of illness

    EPA Science Inventory

    Discharge of stormwater runoff onto beaches is a major cause of beach closings and advisories in the United States. Prospective studies of recreational water quality and health have often been limited to two time points (baseline and follow-up). Little is known about the risk of ...

  11. Field-deployed Metabolomics for Assessing Surface Waters Impacted by Point and Non-Point Sources of Contamination

    EPA Science Inventory

    Metabolomics has become well-established for studying chemical contaminant-induced alterations to normal biological function. For example, the literature contains a wealth of laboratory-based studies involving analysis of samples from organisms exposed to individual chemical toxi...

  12. LANDSCAPE CHARACTERIZATION & NON-POINT SOURCE NITROGEN MODELING IN SUPPORT OF TMDL DEVELOPMENT IN THE NEUSE RIVER BASIN, NC

    EPA Science Inventory



    Pfesteria-like toxic- blooms have been implicated as the causative agent responsible for numerous outbreaks of fish lesions and fish kills in the Mid-Atlantic and southeastern U.S. An increase in frequency, intensity, and severity of toxic blooms in recent years is though...

  13. USING LANDSCAPE ECOLOGY TO MAP WATERSHEDS THAT ARE VULNERABLE TO NON-POINT SOURCE POLLUTION IN THE OZARKS

    EPA Science Inventory

    The U.S. EPA's Office of Research and Development, and U.S. EPA Region 7 have collaborated to map and interpret landscape-scale (i.e. broad-scale) ecological metrics among watershed of the Upper White River, and have produced the first geospatial models of water quality vulnerabi...

  14. In-situ treatment of non-point source pollution part 2: Field results from two different treatment structures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) sorbing materials (PSMs) have been used to reduce dissolved P (DP) concentrations in surface runoff and leachate via applications to soils and animal manure. In August, 2006, a P removal structure filled with an aluminum oxide, iron oxide and calcium sulfate/carbonate rich residual d...

  15. [Dynamic change of non-point source pollution exported from Heigou watershed in Three Gorges Reservoir area].

    PubMed

    Tian, Yao-Wu; Huang, Zhi-Lin; Xiao, Wen-Fa

    2011-02-01

    Sediment and its associated pollutants entering a water body can be very destructive to the ecological health of that system. Based on GIS and AnnAGNPS model, A total of 60 combinations of various management treatments including five fertilizer levels (FL1-existing, FL2-70% of existing, FL3-recommended, FLA-70% of recommended, FL5-30% of recommended), four tillage practices (CT-conventional tillage, NT-no tillage, CS-contour strip cropping, RC-residue cover) and three kinds of annual rainfall (deficit, normal, abundant) have been evaluated. Results from model simulations indicate that runoff and sediment yield were not affected due to change in fertilizer doses, but there was a significant positive correlation between nutrient losses and fertilizer application rates; Conservation tillage practices such as NT, CS and RC would reduce sediment and sediment-bound nutrient losses significantly, they have very little benefit on soluble nitrogen and phosphorus losses. This is primarily because the increased infiltration rates resulting from those practices leads to greater losses of subsurface and return flow in the watershed. In view of feasibility and efficiency, the combination of FL3 + NT was found to be the best scenario as the reductions of nutrient losses and sediment yield were about 40% and 45%, respectively.

  16. USING LANDSCAPE ECOLOGY AND PARTIAL LEAST SQUARES PREDICTIONS TO MAP WATERSHEDS THAT ARE VULNERABLE TO NON-POINT SOURCE POLLUTION

    EPA Science Inventory

    The U.S. Environmental Protection Agency's Office of Research and Development have mapped and interpreted landscape-scale (i.e., broad scale) ecological metrics among watersheds in the upper White River watershed, producing the first geospatial models of water quality vulnerabili...

  17. USING LANDSCAPE ECOLOGY AND PARTIAL LEAST SQUARES PREDICITIONS TO MAP WATERSHEDS THAT ARE VULNERABLE TO NON-POINT SOURCE POLLUTION

    EPA Science Inventory

    The U.S. Environmental Protection Agency¿s Office of Research and Development have mapped and interpreted landscape-scale (i.e., broad scale) ecological metrics among watersheds in the upper White River watershed, producing the first geospatial models of water quality vulnerabili...

  18. Field-deployed Metabolomics for Assessing Waters Impacted by Point and Non-Point Sources of Contamination

    EPA Science Inventory

    Metabolomics is becoming well-established for studying chemical contaminant-induced alterations to normal biological function. For example, the literature contains a wealth of laboratory-based studies involving analysis of samples from organisms exposed to individual chemical tox...

  19. Modeling hydrology, groundwater recharge and non-point nitrate loadings in the Himalayan Upper Yamuna basin.

    PubMed

    Narula, Kapil K; Gosain, A K

    2013-12-01

    The mountainous Himalayan watersheds are important hydrologic systems responsible for much of the water supply in the Indian sub-continent. These watersheds are increasingly facing anthropogenic and climate-related pressures that impact spatial and temporal distribution of water availability. This study evaluates temporal and spatial distribution of water availability including groundwater recharge and quality (non-point nitrate loadings) for a Himalayan watershed, namely, the Upper Yamuna watershed (part of the Ganga River basin). The watershed has an area of 11,600 km(2) with elevation ranging from 6300 to 600 m above mean sea level. Soil and Water Assessment Tool (SWAT), a physically-based, time-continuous model, has been used to simulate the land phase of the hydrological cycle, to obtain streamflows, groundwater recharge, and nitrate (NO3) load distributions in various components of runoff. The hydrological SWAT model is integrated with the MODular finite difference groundwater FLOW model (MODFLOW), and Modular 3-Dimensional Multi-Species Transport model (MT3DMS), to obtain groundwater flow and NO3 transport. Validation of various modules of this integrated model has been done for sub-basins of the Upper Yamuna watershed. Results on surface runoff and groundwater levels obtained as outputs from simulation show a good comparison with the observed streamflows and groundwater levels (Nash-Sutcliffe and R(2) correlations greater than +0.7). Nitrate loading obtained after nitrification, denitrification, and NO3 removal from unsaturated and shallow aquifer zones is combined with groundwater recharge. Results for nitrate modeling in groundwater aquifers are compared with observed NO3 concentration and are found to be in good agreement. The study further evaluates the sensitivity of water availability to climate change. Simulations have been made with the weather inputs of climate change scenarios of A2, B2, and A1B for end of the century. Water yield estimates under

  20. Key questions for conducting role delineation research.

    PubMed

    Taub, Alyson; Gilmore, Gary D; Olsen, Larry K; Connell, Dave

    2011-06-01

    Role delineation research for the verification of professional competencies is essential in many professions to promote quality assurance and support capacity building and workforce development. In this article, guidance is provided about key aspects of role delineation research. The information contained in this article focuses on 13 key questions within three selected research phases when attempting to identify and verify the roles that are inherent within any given profession. The major sections in the paper include planning the research, collecting and analyzing the data, interpreting findings, and considering the future. Recommendations and examples related to each of the important questions are provided to assist others undertaking role delineation research.

  1. 43 CFR 3922.40 - Tract delineation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) OIL SHALE LEASING Application Processing § 3922.40 Tract... the oil shale resource. (b) The BLM may delineate more or less lands than were covered by...

  2. 43 CFR 3922.40 - Tract delineation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing § 3922.40... development of the oil shale resource. (b) The BLM may delineate more or less lands than were covered by...

  3. 43 CFR 3922.40 - Tract delineation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing § 3922.40... development of the oil shale resource. (b) The BLM may delineate more or less lands than were covered by...

  4. 43 CFR 3922.40 - Tract delineation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL SHALE LEASING Application Processing § 3922.40... development of the oil shale resource. (b) The BLM may delineate more or less lands than were covered by...

  5. Automated basin delineation from digital terrain data

    NASA Technical Reports Server (NTRS)

    Marks, D.; Dozier, J.; Frew, J.

    1983-01-01

    While digital terrain grids are now in wide use, accurate delineation of drainage basins from these data is difficult to efficiently automate. A recursive order N solution to this problem is presented. The algorithm is fast because no point in the basin is checked more than once, and no points outside the basin are considered. Two applications for terrain analysis and one for remote sensing are given to illustrate the method, on a basin with high relief in the Sierra Nevada. This technique for automated basin delineation will enhance the utility of digital terrain analysis for hydrologic modeling and remote sensing.

  6. 30 CFR 282.22 - Delineation Plan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Delineation Plan. 282.22 Section 282.22 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR..., minimize, or otherwise mitigate air, land, and water pollution and damage to aquatic and wildlife...

  7. Further delineation of the KBG syndrome.

    PubMed

    Devriendt, K; Holvoet, M; Fryns, J P

    1998-01-01

    Further Delineation of the KBG syndrome: We present a mother and her daughter with clinical features of KBG syndrome, including mild mental retardation, distinct facial features, macrodontia and skeletal anomalies. In the daughter, a heart defect (ventricular septal defect) was present.

  8. Delineation, characterization, and classification of topographic eminences

    NASA Astrophysics Data System (ADS)

    Sinha, Gaurav

    Topographic eminences are defined as upwardly rising, convex shaped topographic landforms that are noticeably distinct in their immediate surroundings. As opposed to everyday objects, the properties of a topographic eminence are dependent not only on how it is conceptualized, but is also intrinsically related to its spatial extent and its relative location in the landscape. In this thesis, a system for automated detection, delineation and characterization of topographic eminences based on an analysis of digital elevation models is proposed. Research has shown that conceptualization of eminences (and other landforms) is linked to the cultural and linguistic backgrounds of people. However, the perception of stimuli from our physical environment is not subject to cultural or linguistic bias. Hence, perceptually salient morphological and spatial properties of the natural landscape can form the basis for generically applicable detection and delineation of topographic eminences. Six principles of cognitive eminence modeling are introduced to develop the philosophical foundation of this research regarding eminence delineation and characterization. The first step in delineating eminences is to automatically detect their presence within digital elevation models. This is achieved by the use of quantitative geomorphometric parameters (e.g., elevation, slope and curvature) and qualitative geomorphometric features (e.g., peaks, passes, pits, ridgelines, and valley lines). The process of eminence delineation follows that of eminence detection. It is posited that eminences may be perceived either as monolithic terrain objects, or as composites of morphological parts (e.g., top, bottom, slope). Individual eminences may also simultaneously be conceived as comprising larger, higher order eminence complexes (e.g., mountain ranges). Multiple algorithms are presented for the delineation of simple and complex eminences, and the morphological parts of eminences. The proposed eminence

  9. WHPA delineation in Rhode Island: Development and statewide application of methodologies. [WellHead Protection Area

    SciTech Connect

    Bradley, M.D.; Kaczor-Bobiak, S.M. )

    1992-01-01

    Wellhead Protection Areas (WHPAs) were delineated for all 525 public drinking water wells in Rhode Island by RI Department of Environmental Management hydrogeology staff. WHPA delineation is an element of the EPA-approved Rhode Island Wellhead Protection Program (RIWHPP), which is designed to protect areas contributing groundwater to public drinking water wells. For resource protection to proceed, legally defensible WHPAs were needed which could be quickly delineated. The authors incorporated input and feedback from a technical subcommittee in developing Rhode Island WHPA delineation methodologies. Comprehensive databases were compiled, which included well parameters and associated aquifer characteristics. More complex delineation techniques were applied to large-capacity wells (average discharge greater than 10 gpm) than to smaller wells. WHPAs for the smaller wells were limited to a 1750-foot-radius circle based on average characteristics of small bedrock wells in Rhode Island. For the large wells, WHPAs consisted of a combination of analytical modelling and hydrogeologic mapping. The Theis equation was used to map the downgradient WHPA boundary for large wells finished in bedrock. The uniform flow equation was used to calculate the downgradient portion of the WHPA for large wells finished in stratified drift. The upgradient boundary for all large wells was delineated using hydrogeologic mapping based on a technique modified from a USGS method. These WHPAs are being provided to municipalities and public water suppliers, who will use them to carry out the other elements of the RIWHPP, such as pollution source inventories, contingency planning, and management approaches.

  10. Case studies in wellhead protection area delineation and monitoring

    SciTech Connect

    Moore, B.A.

    1993-04-01

    Ground-water monitoring is one of many management options for Wellhead Protection Program implementation. Ground-water parameters are monitored (1) to assess source-control measures, (2) to monitor compliance with drinking water standards at sites other than the wellhead, and (3) to provide advance warning of contaminants in ground water. Five case studies are included in the document to exemplify the monitoring methodology for different hydrogeologic and contaminant source settings. The five case study research sites include Stevens Point, Wisconsin; Littleton, MA; Sioux Falls, South Dakota; Dover, New Hampshire; and Springfield, Missouri. The document emphasizes a multi-disciplinary approach for hydrogeologic characterization, wellhead protection area delineation, and flowpath assessment. Hydrogeologic characterization techniques include: well installation, water quality sampling and assessment, geologic and structural-control mapping, aquifer testing, dye tracing, borehole geophysics, analytical solutions, and ground-water flow modeling.

  11. Delinating Thermohaline Double-Diffusive Rayleigh Regimes

    NASA Astrophysics Data System (ADS)

    Graf, T.; Walther, M.; Kolditz, O.; Liedl, R.

    2013-12-01

    In natural systems, convective flow induced from density differences may occur in near-coastal aquifers, atmospheric boundary layers, oceanic streams or within the earth crust. Whether an initially stable, diffusive regime evolves into a convective (stable or chaotic) regime, or vice versa, depends on the system's framing boundary conditions. A conventional parameter to express the relation between diffusive and convective forces of such a density-driven regime is Rayleigh number (Ra). While most systems are mainly dominated by only a single significant driving force (i.e. only temperature or salinity), some systems need to consider two boundary processes (e.g. deep, thus warm, haline flow in porous media). In that case, a two-dimensional, 'double-diffusive' Rayleigh system can be defined. Nield (1998) postulated a boundary between diffusive and convective regime at RaT + RaC = 4pi^2 in the first quadrant (Q1), with Rayleigh numbers for temperature and concentration respectively. The boundary in the forth quadrant (Q4) could not exactly be determined, yet the approximate position estimated. Simulations with HydroGeoSphere (Therrien, 2010) using a vertical, quadratic, homogeneous, isotropic setup confirmed the existence of the 4pi^2-boundary and revealed additional regimes (diffusive, single-roll, double-roll, chaotic) in Q1. Also, non-chaotic, oscillating patterns could be identified in Q4. More detailed investigations with OpenGeoSys (Kolditz, 2012) confirmed the preceding HGS results, and, using a 1:10-scaled domain (height:length), uncovered even more distinctive regimes (diffusive, minimum ten roles, supposely up to 25 roles, and chaotic?) in Q1, while again, oscillating patterns were found in the transition zone between diffusive and chaotic regimes in Q4. Output of numerical simulations from Q1 and Q4 show the mentioned regimes (diffusive, stable-convective, stable-oscillatory, chaotic) while results are displayed in context of a possible delination between

  12. Automated diffraction delineation using an apex-shifted Radon transform

    NASA Astrophysics Data System (ADS)

    Karimpouli, Sadegh; Malehmir, Alireza; Hassani, Hossein; Khoshdel, Hossein; Nabi-Bidhendi, Majid

    2015-04-01

    Diffraction arrivals are important data that have increasingly been used to delineate the sources of diffractors and to explore subsurface discontinuities. In prestack data, diffractions are both zero- and non-zero offset hyperbolas while reflections are only zero-offset hyperbolas. An iterative algorithm using an apex-shifted Radon transform (ASRT) approach is presented in this paper that uses the diffraction hyperbolic trajectory similar to that of prestack time migration in order to locate diffractors and to estimate their corresponding background velocities. Because diffraction energy is generally weak in seismic data and particularly in prestack data, noise attenuation and edge enhancement methods are applied on the instantaneous phase of the seismic data instead of the amplitude data. This means that the phase data are input to the ASRT algorithm. The method is then tested on two synthetic datasets (a point-diffraction model with randomly distributed diffractors and the 2D BP/SEG salt model) and one real data example. Results show that this method can locate the diffractors reasonably well on the rough surfaces of the salt dome and the discontinuities associated with structures such as paleo-channels and faults. Our analysis of the estimated velocities suggests that they are generally valid for diffraction delineation; however, the accuracy of the estimation decreases as background velocity and depth increase.

  13. Nonpoint Source Pollution.

    PubMed

    Ahmad, Zaki Uddin; Sakib, Salman; Gang, Daniel Dianchen

    2016-10-01

    Research advances on non-point source pollution in the year 2015 have been depicted in this review paper. Nonpoint source pollution is mainly caused by agricultural runoff, urban stormwater, and atmospheric deposition. Modeling techniques of NPS with different tools are reviewed in this article.

  14. Chemical treatment response to variations in non-point pollution water quality: results of a factorial design experiment.

    PubMed

    Heiderscheidt, Elisangela; Leiviskä, Tiina; Kløve, Bjørn

    2015-03-01

    Chemical treatment of non-point derived pollution often suffers from undesirable oscillations in purification efficiency due to variations in runoff water quality. This study examined the response of the chemical purification process to variations in water quality using a 2(k) factorial design for runoff water rich in humic substances. The four k factors evaluated and the levels applied were: organic matter as dissolved organic carbon (DOC) (20-70 mg/L), suspended solids (SS) (10-60 mg/L), initial water pH (4.5-7), and applied coagulant dosage (ferric sulphate) (35-100 mg/L). Indicators of purification efficiency were residual concentration of DOC, SS and total phosphorus (tot-P). Analysis of variance and factor effect calculations showed that the initial DOC concentration in raw water samples and its interactions with the coagulant dosage applied exerted the most significant influence on the chemical purification process, substantially affecting the residual concentration of DOC, SS and tot-P. The variations applied to the factors SS and pH only slightly affected purification efficiency. The results can be used in the design of purification systems with high organic matter load variation, e.g. peat extraction runoff.

  15. Trisomy 4 mosaicism: Delineation of the phenotype.

    PubMed

    Bouman, Arjan; van der Kevie-Kersemaekers, Anne-Marie; Huijsdens-van Amsterdam, Karin; Dahhan, Nordin; Knegt, Lia; Vansenne, Fleur; Cobben, Jan Maarten

    2016-04-01

    Trisomy 4 mosaicism in liveborns is very rare. We describe a 17-month-old girl with trisomy 4 mosaicism. Clinical findings in this patient are compared to previously reported patients. Based on the few descriptions available in the literature the common phenotype of trisomy 4 mosaicism seems to consist of IUGR, low birth weight/length/OFC, congenital heart defects, characteristic thumb anomalies (aplasia/hypoplasia), skin abnormalities (hypo-/hyperpigmentation), several dysmorphic features, and likely some degree of intellectual disability. When trisomy 4 mosaicism is suspected clinicians should be aware that a normal karyotype in lymphocytes does not exclude mosaicism for trisomy 4. This report contributes to a further delineation of the phenotype associated with trisomy 4 mosaicism.

  16. Harnessing genomics for delineating conservation units

    PubMed Central

    Funk, W. Chris; McKay, John K.; Hohenlohe, Paul A.; Allendorf, Fred W.

    2014-01-01

    Genomic data have the potential to revolutionize the delineation of conservation units (CUs) by allowing the detection of adaptive genetic variation, which is otherwise difficult for rare, endangered species. In contrast to previous recommendations, we propose that the use of neutral versus adaptive markers should not be viewed as alternatives. Rather, neutral and adaptive markers provide different types of information that should be combined to make optimal management decisions. Genetic patterns at neutral markers reflect the interaction of gene flow and genetic drift that affects genome-wide variation within and among populations. This population genetic structure is what natural selection operates on to cause adaptive divergence. Here, we provide a new framework to integrate data on neutral and adaptive markers to protect biodiversity. PMID:22727017

  17. Harnessing genomics for delineating conservation units.

    PubMed

    Funk, W Chris; McKay, John K; Hohenlohe, Paul A; Allendorf, Fred W

    2012-09-01

    Genomic data have the potential to revolutionize the delineation of conservation units (CUs) by allowing the detection of adaptive genetic variation, which is otherwise difficult for rare, endangered species. In contrast to previous recommendations, we propose that the use of neutral versus adaptive markers should not be viewed as alternatives. Rather, neutral and adaptive markers provide different types of information that should be combined to make optimal management decisions. Genetic patterns at neutral markers reflect the interaction of gene flow and genetic drift that affects genome-wide variation within and among populations. This population genetic structure is what natural selection operates on to cause adaptive divergence. Here, we provide a new framework to integrate data on neutral and adaptive markers to protect biodiversity.

  18. Male pseudohermaphroditism: genetics and clinical delineation.

    PubMed

    Simpson, J L

    1978-10-19

    The genetics and clinical delineation of male pseudohermaphroditism are reviewed. These disorders are categorized initially by their genetic etiology--cytogenetic, Mendelian, or teratogenic. It is especially important to distinguish cytogenetic forms, usually associated with 45,X/46,XY mosaicism, from Mendelian (genetic) forms because in the former the prevalence of gonadoblastomas or dysgerminomas is about 15--20%. Genetic forms include (1) those associated with a multiple malformation pattern, (2) those due to an error in adrenal or testicular hormonal biosynthesis, (3) complete testicular feminization, (4) incomplete testicular feminization, (5) Reifenstein syndrome, (6) pseudovaginal perineoscrotal hypospadias, and (7) agondia, and possibly other conditions. Incomplete testicular feminization and the Reifenstein syndrome may or may not represent varied expressivity of the same trait. The designation pseudovaginal perineoscrotal hypospadias is appropriate only if constellations of clinical features are present and if no metabolic abnormalities are demonstrable. Etiology and available genetic data are reviewed for each of these disorders.

  19. Delineating landfill leachate discharge to an arsenic contaminated waterway.

    PubMed

    Ford, Robert G; Acree, Steven D; Lien, Bob K; Scheckel, Kirk G; Luxton, Todd P; Ross, Randall R; Williams, Aaron G; Clark, Patrick

    2011-11-01

    Discharge of contaminated ground water may serve as a primary and on-going source of contamination to surface water. A field investigation was conducted at a Superfund site in Massachusetts, USA to define the locus of contaminant flux and support source identification for arsenic contamination in a pond abutting a closed landfill. Subsurface hydrology and ground-water chemistry were evaluated in the aquifer between the landfill and the pond during the period 2005-2009 employing a network of wells to delineate the spatial and temporal variability in subsurface conditions. These observations were compared with concurrent measures of ground-water seepage and surface water chemistry within a shallow cove that had a historical visual record of hydrous ferric oxide precipitation along with elevated arsenic concentrations in shallow sediments. Barium, presumably derived from materials disposed in the landfill, served as an indicator of leachate-impacted ground water discharging into the cove. Evaluation of the spatial distributions of seepage flux and the concentrations of barium, calcium, and ammonium-nitrogen indicated that the identified plume primarily discharged into the central portion of the cove. Comparison of the spatial distribution of chemical signatures at depth within the water column demonstrated that direct discharge of leachate-impacted ground water was the source of highest arsenic concentrations observed within the cove. These observations demonstrate that restoration of the impacted surface water body will necessitate control of leachate-impacted ground water that continues to discharge into the cove.

  20. Simultaneous multi-modality ROI delineation in clinical practice.

    PubMed

    Bol, Gijsbert H; Kotte, Alexis N T J; van der Heide, Uulke A; Lagendijk, Jan J W

    2009-11-01

    The delineation of tumors and their surrounding organs at risk is a critical step of the treatment planning for radiation therapy. Besides computer tomography (CT), other imaging modalities are used to improve the quality of the delineations, such as magnetic resonance imaging (MRI) and positron emission tomography (PET). A practical framework is presented for using multiple datasets from different modalities during the delineation phase. The system is based on two basic principles. First, all image datasets of all available modalities are displayed in their original form (in their own coordinate system, with their own spatial resolution and voxel aspect ratio), and second, delineations can take place on all orthogonal views of each dataset and changes made to a delineation are visualized in all image sets, giving direct feedback to the delineator. The major difference between the described approach and other existing delineation tools is that instead of resampling the image sets, the delineations are transformed from one dataset to another. The transformation used for transferring the delineations is obtained by rigid normalized mutual information registration. The crucial components and the benefits of the application are presented and discussed.

  1. Enhancements to TauDEM to support Rapid Watershed Delineation Services

    NASA Astrophysics Data System (ADS)

    Sazib, N. S.; Tarboton, D. G.

    2015-12-01

    Watersheds are widely recognized as the basic functional unit for water resources management studies and are important for a variety of problems in hydrology, ecology, and geomorphology. Nevertheless, delineating a watershed spread across a large region is still cumbersome due to the processing burden of working with large Digital Elevation Model. Terrain Analysis Using Digital Elevation Models (TauDEM) software supports the delineation of watersheds and stream networks from within desktop Geographic Information Systems. A rich set of watershed and stream network attributes are computed. However limitations of the TauDEM desktop tools are (1) it supports only one type of raster (tiff format) data (2) requires installation of software for parallel processing, and (3) data have to be in projected coordinate system. This paper presents enhancements to TauDEM that have been developed to extend its generality and support web based watershed delineation services. The enhancements of TauDEM include (1) reading and writing raster data with the open-source geospatial data abstraction library (GDAL) not limited to the tiff data format and (2) support for both geographic and projected coordinates. To support web services for rapid watershed delineation a procedure has been developed for sub setting the domain based on sub-catchments, with preprocessed data prepared for each catchment stored. This allows the watershed delineation to function locally, while extending to the full extent of watersheds using preprocessed information. Additional capabilities of this program includes computation of average watershed properties and geomorphic and channel network variables such as drainage density, shape factor, relief ratio and stream ordering. The updated version of TauDEM increases the practical applicability of it in terms of raster data type, size and coordinate system. The watershed delineation web service functionality is useful for web based software as service deployments

  2. Delineating groundwater and subsurface structures by

    NASA Astrophysics Data System (ADS)

    Araffa, Sultan Awad Sultan; Helaly, Ahmed S.; Khozium, Ashraf; Lala, Amir M. S.; Soliman, Shokry A.; Hassan, Noha M.

    2015-06-01

    Geophysical tools such as magnetic, gravity and electric resistivity have been used to delineate subsurface structures, groundwater aquifer around Cairo-Belbies Desert road. A dipole-dipole section was measured at the central part of the study area with 2100 m length and electrode spacing 50 m for greater penetration depth. The results of the inverse resistivity data indicate that the study area includes two groundwater aquifers at different depths. The shallow aquifer water is near the surface and the deep aquifer lies at depth of about 115 m and exhibits low resistivity values ranging from 20 to 100 ohm m. One hundred and fifty-two gravity stations were measured using Autograv gravimeter (CG3), different gravity corrections (drift, elevation and latitude corrections) were applied. The corrected data represented by Bouguer anomaly map were filtered into regional and residual gravity anomaly maps. The residual gravity map indicates that the area is dissected by many faults with NW-SE, N-S, E-W and NE-SW trends. One hundred and fifty-three ground magnetic measurements are collected using two Proton magnetometers (Envimag). The corrected magnetic data are represented by total magnetic intensity map that was reduced to the magnetic pole. 3D magnetic modeling was applied to detect the depth of basaltic sheet and basement complex. The results indicated that the elevation of upper surface of basalt is ranging from 148 to -153 m and the elevation of lower surface of basalt is ranging from 148 to 269 m.

  3. Hydrocone groundwater study delineates petroleum contamination

    SciTech Connect

    Prochaska, K.; Hartness, J.; Christenson, K.

    1994-12-31

    Law Environmental, Inc., (LAW), conducted a groundwater survey at Myrtle Beach Air Force Base, South Carolina, to delineate the horizontal and vertical extent of petroleum contamination at the BX Service station. The survey was performed using the In-Situ Technology Hydrocone in conjunction with a field gas chromatograph. The Hydrocone proved to be a reliable, cost-effective method of extracting multi-depth groundwater samples without incurring the expenses associated with the installation and maintenance of monitoring wells. The process generates virtually no investigation-derived waste. The Hydrocone system consists of an elongated cylindrical steel sampler attached to drill rods on a direct push trailer mounted rig. A gas/electronic cable connects to the sampler, and a computer installed on the rig displays pressure on the tool, sampling time, and groundwater volume collected. A total of 18 groundwater samples were collected from 12 locations around the site at sampling depths of approximately 10, 20, and 30 feet below the ground surface. The Hydrocone/gas chromatograph method produced a large volume of groundwater quality data within a relatively short time interval.

  4. Flowpath delineation and ground water age, Allequash Basin, Wisconsin

    USGS Publications Warehouse

    Pint, Christine D.; Hunt, Randall J.; Anderson, Mary P.

    2003-01-01

    An analysis of ground water flowpaths to a lake and creek in northern Wisconsin shows the flow system in a geologically simple basin dominated by lakes can be surprisingly complex. Differences in source area, i.e., lakes or terrestrial, combined with the presence of intervening lakes, which may or may not capture underflowing ground water as water moves downgradient from recharge areas, contribute to a complex mix of flowpaths. The result is water of different chemistry and vastly different ages may discharge in close proximity. Flowpaths, travel times, and capture zones in the Allequash Basin in northern Wisconsin were delineated using particle tracking based on a calibrated steady-state ground water flow model. The flowpath analysis supports the conclusions of Walker et al. (2003) who made inferences about flowpath characteristics from isotope and major ion chemistry. Simulated particle tracking agreed with Walker et al.'s measurements of water source (lake or terrestrial recharge) in the stream subsurface and also supported their assertion that ground water with a high calcium concentration in the lower basin of Allequash Lake is derived from long flowpaths. Numerical simulations show that ground water discharging in this area originates more than 5 km away in a source area located upgradient of Big Muskellunge Lake, which is upgradient of Allequash Lake. These results graphically illustrate that in settings with multiple sources of water with different age characteristics and converging flowlines (like the Allequash Basin) it may be difficult to obtain accurate estimates of ground water age by chemical analyses of ground water.

  5. Mapping and delineating wetlands of Huntington Wildlife Forest using very high resolution digital color-infrared imagery

    NASA Astrophysics Data System (ADS)

    Yavuz, Mehmet

    The effectiveness of off-site wetland delineation methods using very high resolution digital color-infrared aerial imagery (the color-IR imagery) is compared to the traditional on-site wetland delineation method. The on-site delineation results created using the US Fish and Wildlife Service's National Wetland Inventory (NWI map procedures are compared to the following mapping techniques; heads-up digitizing, hybrid classification, Normalized Difference Vegetation Index (NDVI) and unsupervised classifications (ISODATA) using the same image source. Each of the mapping techniques was applied using the seasonal color-IR imagery. Pair-wise significance tests of the closest mean distances indicated that heads-up digitizing was significantly more accurate than other classification techniques for the color-IR imagery. A combination of the heads-up digitizing and the hybrid classification showed that emergent wetland and scrub-shrub wetlands can be delineated without visiting the ground from the color-IR imagery. Applying logarithmic and hyperbolic sine algorithms to enhance the radiometric property of the color-IR imagery increased delineation accuracy 98% in the spring color-IR imagery and 28% in the fall color-IR imagery. Methods for measuring the accuracy of linear features are reviewed and a new method Points-in-Buffer Analysis (PIBA) is proposed. Keywords. Wetland boundary delineation, heads-up digitizing, radiometric enhancement, wetland boundary accuracy, point-in-buffer analysis (PIBA)

  6. Probabilistic capture zone delineation based on an analytic solution.

    PubMed

    Jacobson, Elizabeth; Andricevic, Roko; Morrice, Joseph

    2002-01-01

    A major tool used in the design of wellhead protection areas is the delineation of a capture zone for a pumping well by use of a simple, steady-state analytic solution. This simple approach has been useful for many small municipalities because of the high costs associated with obtaining the hydrogeologic information needed for detailed numerical modeling. This analytic solution, however, is deterministic, and uncertainty in the mean value estimates of the hydraulic parameters used in this model can be a major source of error in predicting capture zones. To address this problem, a statistical theory was developed for including the uncertainty in the transmissivity and the magnitude and direction of the hydraulic head gradient in the analytic solution for both the ultimate and time-dependent capture zone for an arbitrary reliability level. To demonstrate the method and investigate the effect of varying magnitudes of uncertainty on time-dependent capture zones, the method is applied to three synthetic data sets based on data from the Borden Aquifer in Ontario, Canada. In general, the results show that uncertainty in the length of the time-dependent capture zone at a given reliability level is dependent on the uncertainty in the magnitude of the mean regional flow, which is equal to the transmissivity multiplied by the hydraulic head gradient; uncertainty in the maximum width of the capture zone is dependent primarily on the uncertainty in the mean direction of the regional flow.

  7. [Radiotherapy for cervix carcinomas: clinical target volume delineation].

    PubMed

    Gnep, K; Mazeron, R

    2013-10-01

    Concurrent chemoradiation followed by brachytherapy is currently the standard treatment for locally advanced cervix carcinomas. Modern radiation techniques require planning based on 3D images, and therefore an accurate delineation of target volumes. The clinical target volume (CTV) used for the different phases of treatment are now well defined, but are not always easy to delineate on a CT scan which is currently the standard examination for simulation in radiotherapy. MRI and PET-CT are routinely performed at diagnosis, and can be used to improve the accuracy of the delineation. The objective of this review is to describe the definitions and recommendations of CTV in the treatment of cervical cancer.

  8. A strategy for delineating the area of ground-water contribution to wells completed in fractured bedrock aquifers in Pennsylvania

    USGS Publications Warehouse

    Risser, D.W.; Barton, G.J.

    1995-01-01

    Delineating a contributing area to a well completed in a fractured bedrock aquifer in Pennsylvania is difficult because the hydrogeologic characteristics of fractured rocks are extremely complex. Because of this complexity, a single method or technique to delineate a contributing area will not be applicable for all wells completed in fractured-bedrock aquifers. Therefore, a strategy for refining the understanding of boundary conditions and major heterogeneities that control ground-water flow and sources of water to a supply well is suggested. The strategy is based on developing and refining a conceptual model for the sources of water to the well. Specifically, the strategy begins with an initial conceptual model of the ground-water-flow system, then requires the collection of hydrogeologic information to refine the conceptual model in a stepwise manner from one or more of sic categories: (1) hydrogeologic mapping, (2) water-level and streamflow measurements, (3) geochemistry, (4) geophysics and borehole flowmetering, (5) aquifer testing, and (6) tracer testing. During the refinement process, the applicability of treating the fratured-rock aquifer as a hydrologic continuum is evaluated, and the contributing area is delineated. Choice of the method used to delineate the contributing area is less important than insuring that the method is consistent with the refined conceptual model. By use of such a strategy, the improved understanding of the ground-water-flow system will lead to a technically defensible delineation of the contributing area.

  9. The impact of the U.S. biofuels expansion on non-point source pollution from nitrogen in a marginal agricultural area

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Energy Independence Security Act aims to increase the production of renewable fuels in order to improve the energy efficiency of the United States. The goal of this legislation is to produce 36 billion gallons of biofuel, primarily corn ethanol, by 2022. A bioeconomic model is employed, includin...

  10. Development and application of a coupled bio-geochmical and hydrological model for point and non-point source river water pollution

    NASA Astrophysics Data System (ADS)

    Pohlert, T.

    2007-12-01

    The aim of this paper is to present recent developments of an integrated water- and N-balance model for the assessment of land use changes on water and N-fluxes for meso-scale river catchments. The semi-distributed water-balance model SWAT was coupled with algorithms of the bio-geochemical model DNDC as well as the model CropSyst. The new model that is further denoted as SWAT-N was tested with leaching data from a long- term lysimeter experiment as well as results from a 5-years sampling campaign that was conducted at the outlet of the meso-scale catchment of the River Dill (Germany). The model efficiency for N-load as well as the spatial representation of N-load along the river channel that was tested with results taken from longitudinal profiles show that the accuracy of the model has improved due to the integration of the aforementioned process-oriented models. After model development and model testing, SWAT-N was then used for the assessment of the EU agricultural policy (CAP reform) on land use change and consequent changes on N-fluxes within the Dill Catchment. giessen.de/geb/volltexte/2007/4531/

  11. AnnAGNPS – A United States Department of Agriculture Watershed Conservation Management Planning Tool for Non-Point Source Pollution Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A watershed scale assessment of the effect of conservation practices on the environment is critical when recommending best management practices to agricultural producers. The environmental benefits of these practices have not been widely quantified at the watershed scale, which would require extens...

  12. 2. Photocopy of a measured drawing (original delineated the Royal ...

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

    2. Photocopy of a measured drawing (original delineated the Royal Danish Academy of Fine Arts (Kunstakademiets), Copenhagen, Denmark, 1961) FRONT (KING STREET) ELEVATION AND PLANS OF FIRST AND SECOND FLOORS - Kongensgade 58 (House), 58 King Street, Christiansted, St. Croix, VI

  13. 22. Photocopy of drawing Delineator unknown, ca. 1931 Wright Studio, ...

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

    22. Photocopy of drawing Delineator unknown, ca. 1931 Wright Studio, photographer View from Kellogg Blvd. - St. Paul City Hall & Ramsey County Courthouse, 15 West Kellogg Boulevard, Saint Paul, Ramsey County, MN

  14. 356. Delineator Unknown March 1946 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    356. Delineator Unknown March 1946 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; GENERAL DATA; PLAT III - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  15. 10. Photocopy of map (from Benicia Historical Society) Delineator unknown ...

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

    10. Photocopy of map (from Benicia Historical Society) Delineator unknown May 1, 1894, revised to Mar. 27, 1918 'MAP OF BENICIA ARSENAL RESERVATION' - Benicia Arsenal, Benicia Industrial Park, Benicia, Solano County, CA

  16. Photocopy of site plan, Dene Hendrick, delineator, 1977, for the ...

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

    Photocopy of site plan, Dene Hendrick, delineator, 1977, for the City of San Jose in cooperative agreement with the California Department of Transportation (from the San Jose Historical Museum) - Stevens Ranch Complex, State Route 101, Coyote, Santa Clara County, CA

  17. 1. Photocopy of delineation, American Architect and Building News, Vol ...

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

    1. Photocopy of delineation, American Architect and Building News, Vol VI, No. 146, (September 27, 1879). SHOWING FRONT ELEVATION AND FLOOR PLAN - G. B. P. Carpenter House, 100 Block of Polk Streets (Prospect Point), Burlington, Des Moines County, IA

  18. Polymer delineation system. [Patent application: traffic lane lines

    DOEpatents

    Woolman, S.; Steinberg, M.

    1975-06-24

    A delineation system (traffic lane lines) for highways is described in which polymerizable substances are applied to existing or newly prepared highway pavements. The substances would contain a suitable pigment and may incorporate reflective elements.

  19. Applications of Synthetic Aperture Radar (SAR) to UXO Delineation

    DTIC Science & Technology

    2004-05-01

    Synthetic Aperture Radar ( SAR ) to UXO Delineation May 2004 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the...Applications of Synthetic Aperture Radar ( SAR ) to UXO Delineation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...LIMITATION OF ABSTRACT Same as Report ( SAR ) 18. NUMBER OF PAGES 39 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified

  20. Geospatial datasets for watershed delineation and characterization used in the Hawaii StreamStats web application

    USGS Publications Warehouse

    Rea, Alan; Skinner, Kenneth D.

    2012-01-01

    The U.S. Geological Survey Hawaii StreamStats application uses an integrated suite of raster and vector geospatial datasets to delineate and characterize watersheds. The geospatial datasets used to delineate and characterize watersheds on the StreamStats website, and the methods used to develop the datasets are described in this report. The datasets for Hawaii were derived primarily from 10 meter resolution National Elevation Dataset (NED) elevation models, and the National Hydrography Dataset (NHD), using a set of procedures designed to enforce the drainage pattern from the NHD into the NED, resulting in an integrated suite of elevation-derived datasets. Additional sources of data used for computing basin characteristics include precipitation, land cover, soil permeability, and elevation-derivative datasets. The report also includes links for metadata and downloads of the geospatial datasets.

  1. Wellhead protection area delineation under uncertainty

    SciTech Connect

    Jacobson, E.; Andricevic, R.; Hultin, T.

    1994-09-01

    A program to protect groundwater resources used for water supply from all potential threats due to contamination was established in the Amendments to the Safe Drinking Water Act (SDWA). Goal of the State Wellhead Protection (WHP) Program is to ``protect wellhead areas within their jurisdiction from contaminants which may have any adverse effect on the health of persons.`` A major component of WHP is the determination of zones around water-supply wells called Wellhead Protection Areas (WHPAs) within which contaminant source assessment and management should be addressed. WHPAs are defined in the SDWA as ``the surface and subsurface area surrounding a water well or wellfield, supplying a public water system, through which contaminants are reasonably likely to move toward and reach such water well or wellfield.`` A total of 14 water-supply wells are currently being used at the Nevada Test Site (NTS). Eleven of the wells are used for potable water supplies and the remaining three wells are used for construction purposes only. Purpose of this study is to estimate WHPAs for each water-supply well at the NTS. Due to the limited information about the hydraulic properties needed for estimating the WHPAS, an approach that considered the uncertainty in the estimates of the hydraulic properties was developed and implemented.

  2. A pilot study for delineation of areas contributing water to wellfields at Jackson, Tennessee

    USGS Publications Warehouse

    Broshears, R.E.; Connell, J.F.; Short, N.C.

    1991-01-01

    The U.S. Geological Survey, in cooperation with the Tennessee Department of Health and Environment, Division of Groundwater Protection, and the Jackson Utility Division, conducted a pilot study to determine data needs and the applicability of four methods for the delineation of wellhead protection areas. Jackson Utility Division in Jackson, Madison County, Tennessee, pumps about 9 million gallons of ground water daily from two municipal wellfields that tap an unconfined sand aquifer. Under natural hydraulic gradients, ground waterflows southward toward the South Wellfield at approximately 2 to 3 feet per day; natural flow toward the North Wellfield from the east at 1 to 2 feet per day. Water quality generally is suitable for most uses. Concentrations of dissolved solids are low, and excessive iron is the only significant naturally occurring water-quality problem. However, trace concentrations of volatile organic compounds have been detected in water pumps from the South Wellfield; the highest concentration of a single compound has been 23 micrograms per liter of tetrachloroethylene. Potential sources of ground-water contamination in the Jackson area include a hazardous-waste site, municipal and industrial landfill, and underground-storage tanks. Some of the four method for delineating wellhead protection areas did not adequately describe zones contributing flow to the wellfields. Calculations based on a uniform flow equation provided a preliminary delineation of zones of contribution for the wellfields and ground-water time-of-travel contours. Limitations of the applied methods motivated the design of a more rigorous hydrogeologic investigation.

  3. Phosphorus and carbon competitive sorption-desorption and associated non-point loss respond to natural rainfall events

    NASA Astrophysics Data System (ADS)

    Gao, Yang; Zhu, Bo; He, Nianpeng; Yu, Guirui; Wang, Tao; Chen, Weiliang; Tian, Jing

    2014-09-01

    Long-term application of fertilizer or manure can increase the potential for P loss risk to ground and surface waters due to C and P competitive sorption-desorption. The aim of this study was to investigate the effect of long-term agricultural fertilizer application on dissolved organic carbon (DOC) and dissolved total phosphorus (DTP) loss. The study was conducted at the Yanting Agro-Ecological Experimental Station in Sichuan Province, People's Republic of China, during the 2012 rainy season. The results show that the variations in C and P leaching effects in fertilized soils exposed to natural rainfall events. As expected, application of inorganic and organic fertilizers increases DOC and DTP concentrations in soil and decreases the C:P ratio. Similarly, application of inorganic and organic fertilizers results in greater C and P leaching than that seen in unfertilized soils. The DOC flux was higher in subsurface runoff than in overland flow. In contrast, overland flow was the main pathway for P transport; subsurface runoff accounted for a smaller proportion of the total P transport. The increase of DOC and DTP was higher after use of organic manures than after treatment with inorganic fertilizers. DOC derived from surface-applied organic manures was found to leach at higher rates than that seen for DTP derived from the same source. However, organic manure-derived DOC was found to transport from soil prior to P, when they are surface-applied, demonstrating a higher sorption affinity of P over DOC compared to inorganic fertilization. Therefore, we should pay more attention to the P mobilized through long-term fertilization and enhance the P uptake due to C and P competitive sorption-desorption, and avoid potential leaching loss of P during rainfall process.

  4. Towards a High-Resolution Global Inundation Delineation Dataset

    NASA Astrophysics Data System (ADS)

    Fluet-Chouinard, E.; Lehner, B.

    2011-12-01

    Although their importance for biodiversity, flow regulation and ecosystem service provision is widely recognized, wetlands and temporarily inundated landscapes remain poorly mapped globally because of their inherent elusive nature. Inventorying of wetland resources has been identified in international agreements as an essential component of appropriate conservation efforts and management initiatives of these threatened ecosystems. However, despite recent advances in remote sensing surface water monitoring, current inventories of surface water variations remain incomplete at the regional-to-global scale due to methodological limitations restricting truly global application. Remote sensing wetland applications such as SAR L-band are particularly constrained by image availability and heterogeneity of acquisition dates, while coarse resolution passive microwave and multi-sensor methods cannot discriminate distinct surface water bodies. As a result, the most popular global wetland dataset remains to this day the Global Lake & Wetland Database (Lehner and Doll, 2004) a spatially inconsistent database assembled from various existing data sources. The approach taken in this project circumvents the limitations of current global wetland monitoring methods by combining globally available topographic and hydrographic data to downscale coarse resolution global inundation data (Prigent et al., 2007) and thus create a superior inundation delineation map product. The developed procedure downscales inundation data from the coarse resolution (~27km) of current passive microwave sensors to the finer spatial resolution (~500m) of the topographic and hydrographic layers of HydroSHEDS' data suite (Lehner et al., 2006), while retaining the high temporal resolution of the multi-sensor inundation dataset. From the downscaling process emerges new information on the specific location of inundation, but also on its frequency and duration. The downscaling algorithm employs a decision tree

  5. Delineation of wellhead protection areas in fractured rocks

    SciTech Connect

    Bradbu, K.R.; Muldoon, M.A.; Zaporozec, A.; Levy, J.

    1991-06-01

    In 1989, the Wisconsin Geological and Natural History Survey prepared the report under an agreement with the Environmental Protection Agency to evaluate methods for wellhead protection area (WHPA) delineation in unconfined fractured-rock aquifers. Two fractured-rock settings were selected for the study: Precambrian crystalline rocks in central Wisconsin and Silurian dolomite in northeastern Wisconsin. The methods tested ranged from simple approaches to complex computer models. Four WHPA delineation approaches are suggested for unconfined fractured-rock aquifers that do not behave as porous media.

  6. Model assessment for delineating wellhead protection areas. Technical report (Final)

    SciTech Connect

    Van der Heijde, P.; Beljin, M.S.

    1988-05-01

    This report offers a compilation of ground-water computer flow models potentially applicable to Wellhead Protection Areas (WHPA) delineation. EPA's Office of Ground-Water Protection prepared the document in a continuing effort to provide technical assistance to State and local Wellhead Protection Programs based on requirements of the Safe Drinking Water act (SDWA) as amended in 1986. The criteria used to select and evaluate the applicable analytical and numerical models for WHPA delineation is explained in the document and informative reference material of each of 64 models is listed.

  7. Delineating the "galectin signature" of the tumor microenvironment

    PubMed Central

    Compagno, Daniel; Laderach, Diego J.; Gentilini, Lucas; Jaworski, Felipe M.; Rabinovich, Gabriel A.

    2013-01-01

    Galectins, a family of glycan-binding proteins, can control tumor progression by promoting transformation, angiogenesis and immune escape. We identified a dynamically regulated ‘galectin signature’, which delineates the progression of prostate cancer, highlighting galectin-1 as an attractive target for anti-angiogenic therapy in advanced stages of the disease. PMID:23734312

  8. The Regionalization of Africa: Delineating Africa's Subregions Using Airline Data

    ERIC Educational Resources Information Center

    Good, Pieter R.; Derudder, Ben; Witlox, Frank J.

    2011-01-01

    Current regionalizations of Africa have limitations in that they are attribute-based and regions are delineated according to national boundaries. Taking the world city network approach as starting point, it is possible to use relational data (i.e., information about the relationships between cities) rather than attribute data, and moreover, it…

  9. 390. Delineator Unknown October 1933 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    390. Delineator Unknown October 1933 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - EAST BAY CROSSING; SPANS YBI TO El - E9 TO El ; TYPICAL CROSSSECTION; CONTRACT NO. 7; SUP. DRAWING NO. 82 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  10. 375. Delineator Unknown June 1933 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    375. Delineator Unknown June 1933 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; YERBA BUENA CROSSING; ANCHORAGE TUNNELS; CONTRACT NO. 5; DRAWING NO. 10A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  11. 379. Delineator Unknown December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    379. Delineator Unknown December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; CABLES AND ATTACHMENTS - WEST BAY CROSSING; SPLAY CASTINGS; CONTRACT NO. 6A; DRAWING NO. 4 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  12. 385. Delineator Unknown December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    385. Delineator Unknown December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; ROCKER POSTS AND BEARING; CONTRACT NO. 6; DRAWINGS NO. 42 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  13. 380. Delineator Unknown December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    380. Delineator Unknown December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; CABLES & ATTACHMENTS WEST BAY CROSSING; CABLE BANDS; CONTRACT NO. 6A; DRAWING NO. 3 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  14. 402. Delineator Unknown May 2, 1933 STUDY FOR SUSPENSION TOWERS; ...

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

    402. Delineator Unknown May 2, 1933 STUDY FOR SUSPENSION TOWERS; SAN FRANCISCO - OAKLAND BAY BRIDGE; TIMOTHY L. PFLUEGER, ARTHUR BROWN JR., JOHN J. DONOVAN; BOARD OF CONSULTING ARCHITECTS; SCHEME 1A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  15. 404. Delineator Unknown June 1, 1933 STUDY FOR TOP OF ...

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

    404. Delineator Unknown June 1, 1933 STUDY FOR TOP OF SUSPENSION TOWERS; SAN FRANCISCO OAKLAND BAY BRIDGE; TIMOTHY L. PFLUEGER, ARTHUR BROWN JR., JOHN J. DONOVAN; BOARD OF CONSULTING ARCHITECTS; SCHEME 7-A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  16. 407. Delineator Unknown July 11, 1933 PERSPECTIVE STUDY OF SAN ...

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

    407. Delineator Unknown July 11, 1933 PERSPECTIVE STUDY OF SAN FRANCISCO ANCHORAGE; SAN FRANCISCO - OAKLAND BAY BRIDGE; TIMOTHY L. PFLUEGER, ARTHUR BROWN JR., JOHN J. DONOVAN; BOARD OF CONSULTING ARCHITECTS; SHEET 12 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  17. 403. Delineator Unknown May 2, 1933 STUDY FOR SUSPENSION TOWERS; ...

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

    403. Delineator Unknown May 2, 1933 STUDY FOR SUSPENSION TOWERS; SAN FRANCISCO - OAKLAND BAY BRIDGE; TIMOTHY L. PFLUEGER, ARTHUR BROWN JR., JOHN J. DONOVAN; BOARD OF CONSULTING ARCHITECTS; SCHEME 2 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  18. 406. Delineator Unknown April 19, 1933 ELEVATION STUDY FOR SAN ...

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

    406. Delineator Unknown April 19, 1933 ELEVATION STUDY FOR SAN FRANCISCO ANCHORAGE; SAN FRANCISCO - OAKLAND BAY BRIDGE; BOARD OF CONSULTING ARCHITECTS; TIMOTHY L. PFLUEGER, ARTHUR BROWN JR., JOHN J. DONOVAN; SHEET 23 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  19. 408. Delineator Unknown September 19, 1933 SAN FRANCISCO OAKLAND ...

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

    408. Delineator Unknown September 19, 1933 SAN FRANCISCO - OAKLAND BAY BRIDGE; STUDY FOR SAN FRANCISCO ANCHORAGE; TIMOTHY L. PFLUEGER, ARTHUR BROWN JR., JOHN J. DONOVAN; BOARD OF CONSULTING ARCHITECTS; SHEET NO. 26 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  20. Delineation of nuclear structures in 3D multicellular systems

    SciTech Connect

    2013-09-13

    A pipeline, implemented within the Insight Segmentation and Registration Toolkit (ITK) and The Visualization Toolkit (VTK) framework, to delineate each nucleus and to profile morphometric and colony organization. At an abstract level, our approach is an extension of a previously developed method for monolayer call structure models.

  1. 18 CFR 415.43 - Mapped and unmapped delineations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Mapped and unmapped... ADMINISTRATIVE MANUAL BASIN REGULATIONS-FLOOD PLAIN REGULATIONS Administration § 415.43 Mapped and unmapped delineations. (a) Whenever an official flood plain map providing the pertinent information is available...

  2. 18 CFR 415.43 - Mapped and unmapped delineations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Mapped and unmapped... ADMINISTRATIVE MANUAL BASIN REGULATIONS-FLOOD PLAIN REGULATIONS Administration § 415.43 Mapped and unmapped delineations. (a) Whenever an official flood plain map providing the pertinent information is available...

  3. 18 CFR 415.43 - Mapped and unmapped delineations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Mapped and unmapped... ADMINISTRATIVE MANUAL BASIN REGULATIONS-FLOOD PLAIN REGULATIONS Administration § 415.43 Mapped and unmapped delineations. (a) Whenever an official flood plain map providing the pertinent information is available...

  4. 18 CFR 415.43 - Mapped and unmapped delineations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Mapped and unmapped... ADMINISTRATIVE MANUAL BASIN REGULATIONS-FLOOD PLAIN REGULATIONS Administration § 415.43 Mapped and unmapped delineations. (a) Whenever an official flood plain map providing the pertinent information is available...

  5. 18 CFR 415.43 - Mapped and unmapped delineations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Mapped and unmapped... ADMINISTRATIVE MANUAL BASIN REGULATIONS-FLOOD PLAIN REGULATIONS Administration § 415.43 Mapped and unmapped delineations. (a) Whenever an official flood plain map providing the pertinent information is available...

  6. 1. Photocopy of site plan, Dene Hendrick, delineator, 1977, for ...

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

    1. Photocopy of site plan, Dene Hendrick, delineator, 1977, for the City of San Jose in cooperative agreement with the California Department of Transportation (from the San Jose Historical Museum). - Twin Oaks Dairy, Northwest of Metcalfe Road, off State Route 101 (Monterey Road), Coyote, Santa Clara County, CA

  7. 374. Delineator Unknown June 1933 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    374. Delineator Unknown June 1933 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; YERBA BUENA CROSSING; EYE BAR CHAIN; CONTRACT NO. 5; SUP. DRAWING NO. 12A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  8. 362. Delineator Unknown June 1933 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    362. Delineator Unknown June 1933 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SAN FRANCISCO ANCHORAGE; EYE BAR ANCHOR CHAIN; CONTRACT NO. 3; SUP. DRAWING NO. 11-A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  9. Interobserver Variation of Clinical Target Volume Delineation in Gastric Cancer

    SciTech Connect

    Jansen, Edwin; Verheij, Marcel

    2010-07-15

    Purpose: To evaluate interobserver variability in clinical target volume (CTV) delineation in gastric cancer performed with the help of a delineation guide. Patients and Methods: Ten radiotherapy centers that participate in the CRITICS Phase III trial were provided with a delineation atlas, preoperative CT scans, a postoperative planning CT scan, and clinical information for a gastric cancer case and were asked to construct a CTV and create a dosimetric plan according to departmental policy. Results: The volumes of the CTVs and planning target volumes (PTVs) differed greatly, with a mean (SD) CTV volume of 392 (176) cm{sup 3} (range, 240-821cm{sup 3}) and PTV volume of 915 (312) cm{sup 3} (range, 634-1677cm{sup 3}). The overlapping volume was 376cm{sup 3} for the CTV and 890cm{sup 3} for the PTV. The greatest differences in the CTV were seen at the cranial and caudal parts. After planning, dose coverage of the overlapping PTV volume showed less variability than the CTV. Conclusion: In this series of 10 plans, variability of the CTV in postoperative chemoradiotherapy for gastric cancer is large. Strict and clear delineation guidelines should be provided, especially in Phase III multicenter studies. Adaptations of these guidelines should be evaluated in clinical studies.

  10. Dynamic Stereochemistry: A Simple Approach to Delineating Relative Configuration

    ERIC Educational Resources Information Center

    Mandal, Dipak K.

    2007-01-01

    A simple approach for delineating the stereochemistry of the products relative to that of the reactants in reactions involving stereogenic centers is addressed. The reaction at the tetrahedral center involves the cleavage of a bond to one of the ligands in the reactant and the resulting new ligand in the product is labeled by affixing prime to the…

  11. 1. Photocopy of measured drawing (original delineated by the Royal ...

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

    1. Photocopy of measured drawing (original delineated by the Royal Danish Academy of Fine Arts (Kunstakademiets), Copenhagen, Denmark, 1961) WEST ELEVATIONS AND PLAN OF UPPER DRONNINGENSGADE - Dronningensgade Area Study, Ninty-nine Steps, 30-31 Queen Street, Charlotte Amalie, St. Thomas, VI

  12. 359. Delineator Unknown April 1935 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    359. Delineator Unknown April 1935 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; BRIDGE RAILWAY SAN FRANCISCO LOOP; DETAILS OF VIADUCT; FINAL REPORT; DRG. NO. 92 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  13. pn-Junction Delineation in Si Devices Using Scanning Capacitance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Edwards, Hal

    2000-03-01

    The scanning capacitance microscope (SCM) is a carrier-sensitive imaging tool based upon the well-known scanning-probe microscope (SPM). Scanning capacitance spectroscopy (SCS) is a new way to utilize an SCM to delineate pn junctions in Si devices. SCS produces two-dimensional pn-junction maps that show features as small as 10 nm. SCS also provides an estimate of the pn-junction depletion width and hence the doping level near the pn junction. We report SCS measurements of deep-submicron field-effect transistors, showing the source-drain extender profile. We show SCM and SCS data in a failure-analysis application, in which we determined the cause of a leaky field-effect transistor. SCM and SCS are powerful tools for Si bipolar transistors, in which the doping-related structures are quite complex. We show microscopic evidence of the narrow-emitter effect, and image the width of the pn junction to explain an electric field-induced hot-carrier reliability issue. We show a comparison of top-view and cross-sectional SCS measurements of nwell-nwell shallow-trench isolation structures, to reveal the effects of photoresist scumming in sub-design-rule isolation widths. We show initial results on a method to delineate constant-potential contours within the depletion region. We discuss the limits to our present understanding of SCM and SCS and some potential sources of error.

  14. Delineating biophysical environments of the Sunda Banda Seascape, Indonesia.

    PubMed

    Wang, Mingshu; Ahmadia, Gabby N; Chollett, Iliana; Huang, Charles; Fox, Helen; Wijonarno, Anton; Madden, Marguerite

    2015-01-22

    The Sunda Banda Seascape (SBS), located in the center of the Coral Triangle, is a global center of marine biodiversity and a conservation priority. We proposed the first biophysical environmental delineation of the SBS using globally available satellite remote sensing and model-assimilated data to categorize this area into unique and meaningful biophysical classes. Specifically, the SBS was partitioned into eight biophysical classes characterized by similar sea surface temperature, chlorophyll a concentration, currents, and salinity patterns. Areas within each class were expected to have similar habitat types and ecosystem functions. Our work supplemented prevailing global marine management schemes by focusing in on a regional scale with finer spatial resolution. It also provided a baseline for academic research, ecological assessments and will facilitate marine spatial planning and conservation activities in the area. In addition, the framework and methods of delineating biophysical environments we presented can be expanded throughout the whole Coral Triangle to support research and conservation activities in this important region.

  15. A Comparative Review of North American Tundra Delineations

    NASA Technical Reports Server (NTRS)

    Silver, Kirk C.; Carroll, Mark

    2013-01-01

    Recent profound changes have been observed in the Arctic environment, including record low sea ice extents and high latitude greening. Studying the Arctic and how it is changing is an important element of climate change science. The Tundra, an ecoregion of the Arctic, is directly related to climate change due to its effects on the snow ice feedback mechanism and greenhouse gas cycling. Like all ecoregions, the Tundra border is shifting, yet studies and policies require clear delineation of boundaries. There are many options for ecoregion classification systems, as well as resources for creating custom maps. To help decision makers identify the best classification system possible, we present a review of North American Tundra ecoregion delineations and further explore the methodologies, purposes, limitations, and physical properties of five common ecoregion classification systems. We quantitatively compare the corresponding maps by area using a geographic information system.

  16. Population delineation of polar bears using satellite collar data

    USGS Publications Warehouse

    Bethke, R.; Taylor, M.; Amstrup, S.; Messler, F.

    1996-01-01

    To produce reliable estimates of the size or vital rates of a given population, it is important that the boundaries of the population under study are clearly defined. This is particularly critical for large, migratory animals where levels of sustainable harvest are based on these estimates, and where small errors may have serious long-term consequences for the population. Once populations are delineated, rates of exchange between adjacent populations can be determined and accounted/corrected for when calculating abundance (e.g., based on mark-recapture data). Using satellite radio-collar locations for polar bears in the western Canadian Arctic, we illustrate one approach to delineating wildlife populations that integrates cluster analysis methods for determining group membership with home range plotting procedures to define spatial utilization. This approach is flexible with respect to the specific procedures used and provides an objective and quantitative basis for defining population boundaries.

  17. Stratiform/convective rain delineation for TRMM microwave imager

    NASA Astrophysics Data System (ADS)

    Islam, Tanvir; Srivastava, Prashant K.; Dai, Qiang; Gupta, Manika; Wan Jaafar, Wan Zurina

    2015-10-01

    This article investigates the potential for using machine learning algorithms to delineate stratiform/convective (S/C) rain regimes for passive microwave imager taking calibrated brightness temperatures as only spectral parameters. The algorithms have been implemented for the Tropical Rainfall Measuring Mission (TRMM) microwave imager (TMI), and calibrated as well as validated taking the Precipitation Radar (PR) S/C information as the target class variables. Two different algorithms are particularly explored for the delineation. The first one is metaheuristic adaptive boosting algorithm that includes the real, gentle, and modest versions of the AdaBoost. The second one is the classical linear discriminant analysis that includes the Fisher's and penalized versions of the linear discriminant analysis. Furthermore, prior to the development of the delineation algorithms, a feature selection analysis has been conducted for a total of 85 features, which contains the combinations of brightness temperatures from 10 GHz to 85 GHz and some derived indexes, such as scattering index, polarization corrected temperature, and polarization difference with the help of mutual information aided minimal redundancy maximal relevance criterion (mRMR). It has been found that the polarization corrected temperature at 85 GHz and the features derived from the "addition" operator associated with the 85 GHz channels have good statistical dependency to the S/C target class variables. Further, it has been shown how the mRMR feature selection technique helps to reduce the number of features without deteriorating the results when applying through the machine learning algorithms. The proposed scheme is able to delineate the S/C rain regimes with reasonable accuracy. Based on the statistical validation experience from the validation period, the Matthews correlation coefficients are in the range of ~0.60-0.70. Since, the proposed method does not rely on any a priori information, this makes it very

  18. Enhanced delineation of degradation in aortic walls through OCT

    NASA Astrophysics Data System (ADS)

    Real, Eusebio; Val-Bernal, José Fernando; Revuelta, José M.; Pontón, Alejandro; Calvo Díez, Marta; Mayorga, Marta; López-Higuera, José M.; Conde, Olga M.

    2015-03-01

    Degradation of the wall of human ascending thoracic aorta has been assessed through Optical Coherence Tomography (OCT). OCT images of the media layer of the aortic wall exhibit micro-structure degradation in case of diseased aortas from aneurysmal vessels or in aortas prone to aortic dissections. The degeneration in vessel walls appears as low-reflectivity areas due to the invasive appearance of acidic polysaccharides and mucopolysaccharides within a typical ordered microstructure of parallel lamellae of smooth muscle cells, elastin and collagen fibers. An OCT indicator of wall degradation can be generated upon the spatial quantification of the extension of degraded areas in a similar way as conventional histopathology. This proposed OCT marker offers a real-time clinical insight of the vessel status to help cardiovascular surgeons in vessel repair interventions. However, the delineation of degraded areas on the B-scan image from OCT is sometimes difficult due to presence of speckle noise, variable SNR conditions on the measurement process, etc. Degraded areas could be outlined by basic thresholding techniques taking advantage of disorders evidences in B-scan images, but this delineation is not always optimum and requires complex additional processing stages. This work proposes an optimized delineation of degraded spots in vessel walls, robust to noisy environments, based on the analysis of the second order variation of image intensity of backreflection to determine the type of local structure. Results improve the delineation of wall anomalies providing a deeper physiological perception of the vessel wall conditions. Achievements could be also transferred to other clinical scenarios: carotid arteries, aorto-iliac or ilio-femoral sections, intracranial, etc.

  19. Delineation of major soil associations using ERTS-1 imagery

    NASA Technical Reports Server (NTRS)

    Parks, W. L.; Bodenheimer, R. E.

    1973-01-01

    The delineation of a major soil association in the loess region of Obion County has been accomplished using ERTS-1 imagery. Channel 7 provides the clearest differentiation. The separation of other smaller soil associations in an intensive row crop agricultural area is somewhat more difficult. Soil differentiation has been accomplished visually as well as electronically using a scanning microdensitometer. Lower altitude aircraft imagery permits a more refined soil association identification and where imagery is of sufficient scale, even individual soils may be identified.

  20. A locally adaptive kernel regression method for facies delineation

    NASA Astrophysics Data System (ADS)

    Fernàndez-Garcia, D.; Barahona-Palomo, M.; Henri, C. V.; Sanchez-Vila, X.

    2015-12-01

    Facies delineation is defined as the separation of geological units with distinct intrinsic characteristics (grain size, hydraulic conductivity, mineralogical composition). A major challenge in this area stems from the fact that only a few scattered pieces of hydrogeological information are available to delineate geological facies. Several methods to delineate facies are available in the literature, ranging from those based only on existing hard data, to those including secondary data or external knowledge about sedimentological patterns. This paper describes a methodology to use kernel regression methods as an effective tool for facies delineation. The method uses both the spatial and the actual sampled values to produce, for each individual hard data point, a locally adaptive steering kernel function, self-adjusting the principal directions of the local anisotropic kernels to the direction of highest local spatial correlation. The method is shown to outperform the nearest neighbor classification method in a number of synthetic aquifers whenever the available number of hard data is small and randomly distributed in space. In the case of exhaustive sampling, the steering kernel regression method converges to the true solution. Simulations ran in a suite of synthetic examples are used to explore the selection of kernel parameters in typical field settings. It is shown that, in practice, a rule of thumb can be used to obtain suboptimal results. The performance of the method is demonstrated to significantly improve when external information regarding facies proportions is incorporated. Remarkably, the method allows for a reasonable reconstruction of the facies connectivity patterns, shown in terms of breakthrough curves performance.

  1. Delineation of a clinical syndrome caused by mosaic trisomy 15

    SciTech Connect

    Buehler, E.M.; Bienz, G.; Straumann, E.; Bosceh, N.

    1996-03-15

    We report on a boy with mosaic trisomy 15. The clinical manifestations are compared with those of the few cases reported up to now. A clinical syndrome is delineated consisting of a characteristic shape of the nose and other minor craniofacial anomalies, as well as typical deformities of the hands and feet. Different degrees of mosaicism may explain the more or less severe manifestations in individual patients. 10 refs., 4 figs., 1 tab.

  2. Using Groundwater Age and Other Isotopic Signatures to Delineate Groundwater Flow and Stratification

    SciTech Connect

    Moran, J E; Hudson, G B

    2005-08-31

    Isotopic tracers, such as stable isotopes of the water molecule and tritium, have been used in investigations of groundwater flow and transport and recharge water source for several decades. While these data can place hard constraints on groundwater flow rates, the degree of vertical flow between aquifers and across aquitards, and recharge source area(s), they are rarely used, even for validation, in conceptual or numerical models of groundwater flow. The Groundwater Ambient Monitoring and Assessment Program, sponsored by the California State Water Resources Control Board, and carried out in collaboration with the U.S. Geological Survey, has provided the means to gather an unprecedented number of tritium-helium groundwater ages in the basins of California. As the examples below illustrate, a collection of groundwater ages in a basin allows delineation of recharge areas (youngest ages), bulk flow rates and flowpaths, as well as a means of assessing susceptibility to anthropogenic contaminants.

  3. Methods for Data-based Delineation of Spatial Regions

    SciTech Connect

    Wilson, John E.

    2012-10-01

    In data analysis, it is often useful to delineate or segregate areas of interest from the general population of data in order to concentrate further analysis efforts on smaller areas. Three methods are presented here for automatically generating polygons around spatial data of interest. Each method addresses a distinct data type. These methods were developed for and implemented in the sample planning tool called Visual Sample Plan (VSP). Method A is used to delineate areas of elevated values in a rectangular grid of data (raster). The data used for this method are spatially related. Although VSP uses data from a kriging process for this method, it will work for any type of data that is spatially coherent and appears on a regular grid. Method B is used to surround areas of interest characterized by individual data points that are congregated within a certain distance of each other. Areas where data are “clumped” together spatially will be delineated. Method C is used to recreate the original boundary in a raster of data that separated data values from non-values. This is useful when a rectangular raster of data contains non-values (missing data) that indicate they were outside of some original boundary. If the original boundary is not delivered with the raster, this method will approximate the original boundary.

  4. Delineation of regional arid karstic aquifers: an integrative data approach.

    PubMed

    Wolaver, Brad D; Sharp, John M; Rodriguez, Juan M; Flores, Juan Carlos Ibarra

    2008-01-01

    This research integrates data procedures for the delineation of regional ground water flow systems in arid karstic basins with sparse hydrogeologic data using surface topography data, geologic mapping, permeability data, chloride concentrations of ground water and precipitation, and measured discharge data. This integrative data analysis framework can be applied to evaluate arid karstic aquifer systems globally. The accurate delineation of ground water recharge areas in developing aquifer systems with sparse hydrogeologic data is essential for their effective long-term development and management. We illustrate the use of this approach in the Cuatrociénegas Basin (CCB) of Mexico. Aquifers are characterized using geographic information systems for ground water catchment delineation, an analytical model for interbasin flow evaluation, a chloride balance approach for recharge estimation, and a water budget for mapping contributing catchments over a large region. The test study area includes the CCB of Coahuila, Mexico, a UNESCO World Biosphere Reserve containing more than 500 springs that support ground water-dependent ecosystems with more than 70 endemic organisms and irrigated agriculture. We define recharge areas that contribute local and regional ground water discharge to springs and the regional flow system. Results show that the regional aquifer system follows a topographic gradient that during past pluvial periods may have linked the Río Nazas and the Río Aguanaval of the Sierra Madre Occidental to the Río Grande via the CCB and other large, currently dry, upgradient lakes.

  5. Delineating the Rattlesnake Springs, New Mexico Watershed Using Shallow Subsurface Geophysical Techniques and Geologic Mapping

    NASA Astrophysics Data System (ADS)

    Doser, D. I.; Langford, R. P.; Boykov, N. D.; Baker, M. R.; Kaip, G. M.

    2007-12-01

    Rattlesnake Springs serves as the sole water source for Carlsbad Caverns National Park. The recent development of oil and gas leases and agricultural lands surrounding the springs has led to concern about contamination of the karst aquifer. We have used geophysical techniques, combined with geologic mapping, to delineate possible fracture systems in the gypsum and carbonate bedrock that feed the spring system. Our initial work has focused on a 700 m by 700 m region surrounding the springs. We conducted a series of ground conductivity surveys with follow-up DC resistivity surveys (Wenner array vertical electrical soundings and a pole- pole survey) to determine variations in soil grain size and moisture content. Surface geologic mapping was used to identify a series of Holocene terraces and valleys that incise the terraces. Our combined results suggest that northwest-southeast and north-south trending fractures and dissolution features control regional water flow. Relict spring valleys are found to the west of the present springs. A pole-pole survey conducted around the perimeter of the springs suggests main water flow into the springs occurs from the northwest. We plan to complete a precision gravity survey in September and October 2007 to map bedrock topography and determine its relation to structural and dissolution features. Ground penetrating radar data will be collected on the northwestern side of the springs in an attempt to better delineate structures controlling inflow into the springs.

  6. Ground-Water Capture Zone Delineation of Hypothetical Systems: Methodology Comparison and Real-World Applications

    NASA Astrophysics Data System (ADS)

    Ahern, J. A.; Lilly, M. R.; Hinzman, L. D.

    2003-12-01

    A capture zone is the aquifer volume through which ground-water flows to a pumping well over a given time of travel. Determining a well's capture zone aids in water-supply management by creating an awareness of the water source. This helps ensure sustainable pumping operations and outlines areas where protection from contamination is critical. We are delineating the capture zones of hypothetical conceptual models that resemble the Fairbanks, Alaska floodplain both in aquifer parameters and boundary conditions. We begin with a very simple hydrogeologic system and gradually add complexity such as heterogeneity, anisotropy, multiple wells, and zones of permafrost. Commonly-used delineation methods are applied to each case. These include calculated fixed-radius, analytical and numerical models. The calculated fixed-radius method uses a mathematical equation with several simplifying assumptions. Analytical techniques employ a series of equations that likewise assume simple conditions, although to a lesser degree than the fixed-radius method. Our chosen numerical model is MODFLOW-2000, which offers a particle-tracking package (MODPATH) for delineating recharge areas. The delineations are overlayed for each conceptual model in order to compare the capture zones produced by the different methods. Contrasts between capture zones increase with the complexity of the hydrogeology. Simpler methods are restricted by their underlying assumptions. When methods can no longer account for complexities in the conceptual model, the resulting delineations remain similar to those of simpler models. Meanwhile, the zones generated by more sophisticated methods are able to change with changes to the conceptual model. Hence, the simpler methods now lack accuracy and credibility. We have found that these simpler techniques tend to overestimate the capture zone. Water-supply managers must consider such inaccuracies when evaluating the costs of each method. In addition to comparing delineation

  7. Plume Delineation in the BC Cribs and Trenches Area

    SciTech Connect

    Rucker, Dale F.; Sweeney, Mark D.

    2004-11-30

    HydroGEOPHYSICS, Inc. and Pacific Northwest National Laboratory (PNNL) were contracted by Fluor Hanford Group, Inc. to conduct a geophysical investigation in the area of the BC Cribs and Trenches (subject site) at the Hanford Site in Richland, Washington. The BC Cribs and Trenches are located south of the 200 East Area. This document provides the details of the investigation to identify existing infrastructure from legacy disposal activities and to delineate the edges of a groundwater plume that contains radiological and heavy metal constituents beneath the 216-B-26 and 216-B-52 Trenches, and the 216-B-14 through 216-B-19 Cribs.

  8. 12. J. Fuss, delineator (from Folder 5) 'PLAN ETC. OF ...

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

    12. J. Fuss, delineator (from Folder 5) 'PLAN ETC. OF NEW ARSENAL FOR BENICIA DEPOT CAL.' PLAN, ELEVATIONS, SECTIONS, DETAILS (right half of CA-1828-13) 13. (From Folder 5) PLAN, ELEVATION, SECTION (left half of CA-1828-12) 14. (From Folder 2) PLAN, ELEVATION, AND DETAILS OF STONES TO BE CUT 15. (From Folder 4) PLAN AND ELEVATION OF MAIN DOORWAY 16. (From Folder 5) DETAILS OF CANNON EMBRASURES - Benicia Arsenal, Storehouse, Comandant's Lane, Benicia Industrial Park, Benicia, Solano County, CA

  9. An algorithm for microscopic specimen delineation and focus candidate selection.

    PubMed

    Fan, Yilun; Gal, Yaniv; Bradley, Andrew P

    2014-11-01

    In this paper, we compare four field-of-view (FOV) metrics that, when applied to a low-resolution image of a microscope slide, are capable of both accurately delineating the specimen and selecting a subset of focus candidate FOVs required for construction of high-resolution focus map. The metrics evaluated are: threshold index (TI) that measures image intensity; normalised auto-correlation index (NACI) that measures spatial image similarity; auto-phase correlation index (APCI) that measures image phase diversity; and entropy index (EI) that measures the predictability of image intensities. Experiments are undertaken on a data set of forty slides including PAP stained Thin-prep cervical cytology and breast fine-needle aspiration slides and haematoxylin and eosin (HE) stained histology slides. These slides were scanned on an automated bright-field microscope and chosen to be indicative of a variety pathology specimens, containing artefacts such as excess coverslip glue and ink markers. Results are presented on the performance of each metric for correct ranking/segmentation of foreground (specimen) from background, and subsequently selecting focus candidate FOVs characteristic of the specimen's focal plane(s). The experimental results demonstrate that while NACI, APCI and EI are all effective at specimen delineation, only APCI is capable of effectively selecting superior focus candidates and ignoring artefacts.

  10. Delineating Biophysical Environments of the Sunda Banda Seascape, Indonesia

    PubMed Central

    Wang, Mingshu; Ahmadia, Gabby N.; Chollett, Iliana; Huang, Charles; Fox, Helen; Wijonarno, Anton; Madden, Marguerite

    2015-01-01

    The Sunda Banda Seascape (SBS), located in the center of the Coral Triangle, is a global center of marine biodiversity and a conservation priority. We proposed the first biophysical environmental delineation of the SBS using globally available satellite remote sensing and model-assimilated data to categorize this area into unique and meaningful biophysical classes. Specifically, the SBS was partitioned into eight biophysical classes characterized by similar sea surface temperature, chlorophyll a concentration, currents, and salinity patterns. Areas within each class were expected to have similar habitat types and ecosystem functions. Our work supplemented prevailing global marine management schemes by focusing in on a regional scale with finer spatial resolution. It also provided a baseline for academic research, ecological assessments and will facilitate marine spatial planning and conservation activities in the area. In addition, the framework and methods of delineating biophysical environments we presented can be expanded throughout the whole Coral Triangle to support research and conservation activities in this important region. PMID:25648170

  11. Molecular delineation of species in the coral holobiont.

    PubMed

    Stat, Michael; Baker, Andrew C; Bourne, David G; Correa, Adrienne M S; Forsman, Zac; Huggett, Megan J; Pochon, Xavier; Skillings, Derek; Toonen, Robert J; van Oppen, Madeleine J H; Gates, Ruth D

    2012-01-01

    The coral holobiont is a complex assemblage of organisms spanning a diverse taxonomic range including a cnidarian host, as well as various dinoflagellate, prokaryotic and acellular symbionts. With the accumulating information on the molecular diversity of these groups, binomial species classification and a reassessment of species boundaries for the partners in the coral holobiont is a logical extension of this work and will help enhance the capacity for comparative research among studies. To aid in this endeavour, we review the current literature on species diversity for the three best studied partners of the coral holobiont (coral, Symbiodinium, prokaryotes) and provide suggestions for future work on systematics within these taxa. We advocate for an integrative approach to the delineation of species using both molecular genetics in combination with phenetic characters. We also suggest that an a priori set of criteria be developed for each taxonomic group as no one species concept or accompanying set of guidelines is appropriate for delineating all members of the coral holobiont.

  12. Medical staff appointment and delineation of pediatric privileges in hospitals.

    PubMed

    Rauch, Daniel A

    2012-04-01

    The review and verification of credentials and the granting of clinical privileges are required of every hospital to ensure that members of the medical staff are competent and qualified to provide specified levels of patient care. The credentialing process involves the following: (1) assessment of the professional and personal background of each practitioner seeking privileges; (2) assignment of privileges appropriate for the clinician's training and experience; (3) ongoing monitoring of the professional activities of each staff member; and (4) periodic reappointment to the medical staff on the basis of objectively measured performance. We examine the essential elements of a credentials review for initial and renewed medical staff appointments along with suggested criteria for the delineation of clinical privileges. Sample forms for the delineation of privileges can be found on the American Academy of Pediatrics Committee on Hospital Care Web site (http://www.aap.org/visit/cmte19.htm). Because of differences among individual hospitals, no 1 method for credentialing is universally applicable. The medical staff of each hospital must, therefore, establish its own process based on the general principles reviewed in this report. The issues of medical staff membership and credentialing have become very complex, and institutions and medical staffs are vulnerable to legal action. Consequently, it is advisable for hospitals and medical staffs to obtain expert legal advice when medical staff bylaws are constructed or revised.

  13. Automated delineation and characterization of watersheds for more than 3,000 surface-water-quality monitoring stations active in 2010 in Texas

    USGS Publications Warehouse

    Archuleta, Christy-Ann M.; Gonzales, Sophia L.; Maltby, David R.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Texas Commission on Environmental Quality, developed computer scripts and applications to automate the delineation of watershed boundaries and compute watershed characteristics for more than 3,000 surface-water-quality monitoring stations in Texas that were active during 2010. Microsoft Visual Basic applications were developed using ArcGIS ArcObjects to format the source input data required to delineate watershed boundaries. Several automated scripts and tools were developed or used to calculate watershed characteristics using Python, Microsoft Visual Basic, and the RivEX tool. Automated methods were augmented by the use of manual methods, including those done using ArcMap software. Watershed boundaries delineated for the monitoring stations are limited to the extent of the Subbasin boundaries in the USGS Watershed Boundary Dataset, which may not include the total watershed boundary from the monitoring station to the headwaters.

  14. Digital database architecture and delineation methodology for deriving drainage basins, and a comparison of digitally and non-digitally derived numeric drainage areas

    USGS Publications Warehouse

    Dupree, Jean A.; Crowfoot, Richard M.

    2012-01-01

    The drainage basin is a fundamental hydrologic entity used for studies of surface-water resources and during planning of water-related projects. Numeric drainage areas published by the U.S. Geological Survey water science centers in Annual Water Data Reports and on the National Water Information Systems (NWIS) Web site are still primarily derived from hard-copy sources and by manual delineation of polygonal basin areas on paper topographic map sheets. To expedite numeric drainage area determinations, the Colorado Water Science Center developed a digital database structure and a delineation methodology based on the hydrologic unit boundaries in the National Watershed Boundary Dataset. This report describes the digital database architecture and delineation methodology and also presents the results of a comparison of the numeric drainage areas derived using this digital methodology with those derived using traditional, non-digital methods. (Please see report for full Abstract)

  15. 3D MRI-based tumor delineation of ocular melanoma and its comparison with conventional techniques

    SciTech Connect

    Daftari, Inder k; Aghaian, Elsa; O'Brien, Joan M.; Dillon, William; Phillips, Theodore L.

    2005-11-15

    The aim of this study is to (1) compare the delineation of the tumor volume for ocular melanoma on high-resolution three-dimensional (3D) T2-weighted fast spin echo magnetic resonance imaging (MRI) images with conventional techniques of A- and B-scan ultrasound, transcleral illumination, and placement of tantalum markers around tumor base and (2) to evaluate whether the surgically placed marker ring tumor delineation can be replaced by 3D MRI based tumor delineation. High-resolution 3D T2-weighted fast spin echo (3D FSE) MRI scans were obtained for 60 consecutive ocular melanoma patients using a 1.5 T MRI (GE Medical Systems, Milwaukee, WI), in a standard head coil. These patients were subsequently treated with proton beam therapy at the UC Davis Cyclotron, Davis, CA. The tumor was delineated by placement of tantalum rings (radio-opaque markers) around the tumor periphery as defined by pupillary transillumination during surgery. A point light source, placed against the sclera, was also used to confirm ring agreement with indirect ophthalmoscopy. When necessary, intraoperative ultrasound was also performed. The patients were planned using EYEPLAN software and the tumor volumes were obtained. For analysis, the tumors were divided into four categories based on tumor height and basal diameter. In order to assess the impact of high-resolution 3D T2 FSE MRI, the tumor volumes were outlined on the MRI scans by two independent observers and the tumor volumes calculated for each patient. Six (10%) of 60 patients had tumors, which were not visible on 3D MRI images. These six patients had tumors with tumor heights {<=}3 mm. A small intraobserver variation with a mean of (-0.22{+-}4)% was seen in tumor volumes delineated by 3D T2 FSE MR images. The ratio of tumor volumes measured on MRI to EYEPLAN for the largest to the smallest tumor volumes varied between 0.993 and 1.02 for 54 patients. The tumor volumes measured directly on 3D T2 FSE MRI ranged from 4.03 to 0.075 cm{sup 3

  16. 3D MRI-based tumor delineation of ocular melanoma and its comparison with conventional techniques.

    PubMed

    Daftari, Inder k; Aghaian, Elsa; O'Brien, Joan M; Dillon, William; Phillips, Theodore L

    2005-11-01

    The aim of this study is to (1) compare the delineation of the tumor volume for ocular melanoma on high-resolution three-dimensional (3D) T2-weighted fast spin echo magnetic resonance imaging (MRI) images with conventional techniques of A- and B-scan ultrasound, transcleral illumination, and placement of tantalum markers around tumor base and (2) to evaluate whether the surgically placed marker ring tumor delineation can be replaced by 3D MRI based tumor delineation. High-resolution 3D T2-weighted fast spin echo (3D FSE) MRI scans were obtained for 60 consecutive ocular melanoma patients using a 1.5 T MRI (GE Medical Systems, Milwaukee, WI), in a standard head coil. These patients were subsequently treated with proton beam therapy at the UC Davis Cyclotron, Davis, CA. The tumor was delineated by placement of tantalum rings (radio-opaque markers) around the tumor periphery as defined by pupillary transillumination during surgery. A point light source, placed against the sclera, was also used to confirm ring agreement with indirect ophthalmoscopy. When necessary, intraoperative ultrasound was also performed. The patients were planned using EYEPLAN software and the tumor volumes were obtained. For analysis, the tumors were divided into four categories based on tumor height and basal diameter. In order to assess the impact of high-resolution 3D T2 FSE MRI, the tumor volumes were outlined on the MRI scans by two independent observers and the tumor volumes calculated for each patient. Six (10%) of 60 patients had tumors, which were not visible on 3D MRI images. These six patients had tumors with tumor heights < or = 3 mm. A small intraobserver variation with a mean of (-0.22 +/- 4)% was seen in tumor volumes delineated by 3D T2 FSE MR images. The ratio of tumor volumes measured on MRI to EYEPLAN for the largest to the smallest tumor volumes varied between 0.993 and 1.02 for 54 patients. The tumor volumes measured directly on 3D T2 FSE MRI ranged from 4.03 to 0.075 cm3

  17. How to Manual: How to Update and Enhance Your Local Source Water Protection Assessments

    EPA Pesticide Factsheets

    Describes opportunities for improving source water assessments performed under the Safe Drinking Water Act 1453. It includes: local delineations, potential contaminant source inventories, and susceptibility determinations of source water assessment.

  18. Computer-aided boundary delineation of agricultural lands

    NASA Technical Reports Server (NTRS)

    Cheng, Thomas D.; Angelici, Gary L.; Slye, Robert E.; Ma, Matt

    1989-01-01

    The National Agricultural Statistics Service of the United States Department of Agriculture (USDA) presently uses labor-intensive aerial photographic interpretation techniques to divide large geographical areas into manageable-sized units for estimating domestic crop and livestock production. Prototype software, the computer-aided stratification (CAS) system, was developed to automate the procedure, and currently runs on a Sun-based image processing system. With a background display of LANDSAT Thematic Mapper and United States Geological Survey Digital Line Graph data, the operator uses a cursor to delineate agricultural areas, called sampling units, which are assigned to strata of land-use and land-cover types. The resultant stratified sampling units are used as input into subsequent USDA sampling procedures. As a test, three counties in Missouri were chosen for application of the CAS procedures. Subsequent analysis indicates that CAS was five times faster in creating sampling units than the manual techniques were.

  19. Snow Pattern Delineation Using Ground Observations, Remote Sensing, and Modeling

    NASA Astrophysics Data System (ADS)

    Hiemstra, C. A.; Wagner, A. M.; Sturm, M.; Deeb, E. J.

    2013-12-01

    Regardless of the precipitation received, snow depth patterns tend to repeat on landscapes year after year (Sturm and Wagner, 2010). For example, windswept ridges with sparse vegetation have shallow snow while water tracks and swales are deeper. If snow patterns can be consistently identified, understood, and classified using ground observations, remote sensing, models, or some combination thereof, an untapped potential exists to expand and improve snow assessments and predictions. Pattern detection, repeatability, and efficacy have been demonstrated for images and data from a nested study area located on Alaska's North Slope. As a part of the SnowNet project, well over 200,000 snow depths and hundreds of snow densities have been measured during spring measurement campaigns from 2010-2013. Most of the measurements were collected at the core 1km2 Imnavait Creek watershed (where snow measurements have occurred since the early 1980s), with sparser (but still high volume) data collected from the outer 6km2 and 21km2 areas. Imagery collected for the same areas include snow cover from Landsat (30 m) from 1982-present and fine-resolution commercial imagery (0.5-3 m) from 2002-present. While winter imagery is useful for delineating snow-free ridges and windswept areas, of more value were the 12 mid-melt images which allowed us to identify deeper snowpack areas. We also simulated snow distributions from 2010-2013 using SnowModel, which uses topography, land cover, and meteorological data to realistically simulate snow accumulation and ablation over our domains. The time series of over 200,000 individual observations, over 40 images, and four years of model simulations show striking repeatability in snow depth patterns and among years. The spatial agreements among ground observations, satellite-derived snow cover, and SnowModel are remarkable. Our results show a strong fidelity to patterns appearing in three different snow cover and depth estimate approaches, and suggest the

  20. Electrocardiogram ST-Segment Morphology Delineation Method Using Orthogonal Transformations

    PubMed Central

    2016-01-01

    Differentiation between ischaemic and non-ischaemic transient ST segment events of long term ambulatory electrocardiograms is a persisting weakness in present ischaemia detection systems. Traditional ST segment level measuring is not a sufficiently precise technique due to the single point of measurement and severe noise which is often present. We developed a robust noise resistant orthogonal-transformation based delineation method, which allows tracing the shape of transient ST segment morphology changes from the entire ST segment in terms of diagnostic and morphologic feature-vector time series, and also allows further analysis. For these purposes, we developed a new Legendre Polynomials based Transformation (LPT) of ST segment. Its basis functions have similar shapes to typical transient changes of ST segment morphology categories during myocardial ischaemia (level, slope and scooping), thus providing direct insight into the types of time domain morphology changes through the LPT feature-vector space. We also generated new Karhunen and Lo ève Transformation (KLT) ST segment basis functions using a robust covariance matrix constructed from the ST segment pattern vectors derived from the Long Term ST Database (LTST DB). As for the delineation of significant transient ischaemic and non-ischaemic ST segment episodes, we present a study on the representation of transient ST segment morphology categories, and an evaluation study on the classification power of the KLT- and LPT-based feature vectors to classify between ischaemic and non-ischaemic ST segment episodes of the LTST DB. Classification accuracy using the KLT and LPT feature vectors was 90% and 82%, respectively, when using the k-Nearest Neighbors (k = 3) classifier and 10-fold cross-validation. New sets of feature-vector time series for both transformations were derived for the records of the LTST DB which is freely available on the PhysioNet website and were contributed to the LTST DB. The KLT and LPT

  1. Analysis of lidar elevation data for improved identification and delineation of lands vulnerable to sea-level rise

    USGS Publications Warehouse

    Gesch, D.B.

    2009-01-01

    The importance of sea-level rise in shaping coastal landscapes is well recognized within the earth science community, but as with many natural hazards, communicating the risks associated with sea-level rise remains a challenge. Topography is a key parameter that influences many of the processes involved in coastal change, and thus, up-to-date, high-resolution, high-accuracy elevation data are required to model the coastal environment. Maps of areas subject to potential inundation have great utility to planners and managers concerned with the effects of sea-level rise. However, most of the maps produced to date are simplistic representations derived from older, coarse elevation data. In the last several years, vast amounts of high quality elevation data derived from lidar have become available. Because of their high vertical accuracy and spatial resolution, these lidar data are an excellent source of up-to-date information from which to improve identification and delineation of vulnerable lands. Four elevation datasets of varying resolution and accuracy were processed to demonstrate that the improved quality of lidar data leads to more precise delineation of coastal lands vulnerable to inundation. A key component of the comparison was to calculate and account for the vertical uncertainty of the elevation datasets. This comparison shows that lidar allows for a much more detailed delineation of the potential inundation zone when compared to other types of elevation models. It also shows how the certainty of the delineation of lands vulnerable to a given sea-level rise scenario is much improved when derived from higher resolution lidar data. ?? 2009 Coastal Education and Research Foundation.

  2. The Valley Bottom Extraction Tool (V-BET): A GIS tool for delineating valley bottoms across entire drainage networks

    NASA Astrophysics Data System (ADS)

    Gilbert, Jordan T.; Macfarlane, William W.; Wheaton, Joseph M.

    2016-12-01

    The shape, size and extent of a valley bottom dictates the form and function of the associated river or stream. Consequently, accurate, watershed-wide delineation of valley bottoms is increasingly recognized as a necessary component of watershed management. While many valley bottom delineation approaches exist, methods that can be effectively applied across entire drainage networks to produce reasonably accurate results are lacking. Most existing tools are designed to work using high resolution topography data (i.e. > 2 m resolution Digital Elevation Model (DEM)) and can only be applied over relatively short reach lengths due to computational or data availability limitations. When these precise mapping approaches are applied throughout drainage networks (i.e. 102-104 km), the computational techniques often either do not scale, or the algorithms perform inconsistently. Other tools that produce outputs at broader scale extents generally utilize coarser input topographic data to produce more poorly resolved valley bottom approximations. To fill this methodology gap and produce relatively accurate valley bottoms over large areas, we developed an algorithm that accepts terrain data from one to 10 m with slope and valley width parameters that scale based on drainage area, allowing for watershed-scale valley bottom delineation. We packaged this algorithm in the Valley Bottom Extraction Tool (V-BET) as an open-source ArcGIS toolbox for ease of use. To illustrate V-BET's scalability and test the tool's robustness across different physiographic settings, we delineated valley bottoms for the entire perennial drainage network of Utah as well as twelve watersheds across the interior Columbia River Basin (totaling 55,400 km) using 10 m DEMs. We found that even when driven with relatively coarse data (10 m DEMs), V-BET produced a relatively accurate approximation of valley bottoms across the entire watersheds of these diverse physiographic regions.

  3. Areal 3-D seismic technique for reservoir delineation: Case history from offshore Niger Delta

    SciTech Connect

    Idowu, A.O. )

    1993-02-01

    In the 1950s, early exploration period in the Niger Delta witnessed the use of 2-D (two dimensional) seismic reflection method which adequate for imaging large subsurface geologic features including growth faulting and roll-over anticlines. This technique involves the Common-Depth-Point method (CDP) which acquires a plane of seismic information in distance along the surface and in time into the geological section, and is used to improve the signal-to-noise (S/N) ratio, to remove multiples and consequently give a representation of the subsurface particularly if the data are collected up- or downdip. By mid-1980s, the obvious geological structures have, in general, been discovered and it became necessary to adopt a more sophisticated technique such as the 3-D (three dimensional) seismic method to delineate more subtle reservoirs and resolve complex fault patterns in order to aid exploration as well as facilitate efficient field development. The case history discussed in this paper involves the use of areal 3-D seismic method for delineating the reservoir characterization of the O-field located in a shallow water area of the western Niger Delta. The areal 3-D seismic technique is superior to the earlier CDP method in that a cube of seismic data can be collected in two dimensions in space and one in time by a variety of techniques including the swath seismic shooting pattern adopted for gathering the 3-D data for the O-field's reservoir which involves the line of sources. The objective is to adequately sample the subsurface so that changes in various parameters such as the amplitude phase or power in the siesmic signal or velocity of propagation can be mapped areally and interpreted as an indication of changes in the physical properties of the rock matrix.

  4. Delineating depth to bedrock beneath shallow unconfined aquifers: a gravity transect across the Palmer River Basin.

    PubMed

    Bohidar, R N; Sullivan, J P; Hermance, J F

    2001-01-01

    In view of the increasing demand on ground water supplies in the northeastern United States, it is imperative to develop appropriate methods to geophysically characterize the most widely used sources of ground water in the region: shallow unconfined aquifers consisting of well-sorted, stratified glacial deposits laid down in bedrock valleys and channels. The gravity method, despite its proven value in delineating buried bedrock valleys elsewhere, is seldom used by geophysical contractors in this region. To demonstrate the method's effectiveness for evaluating such aquifers, a pilot study was undertaken in the Palmer River Basin in southeastern Massachusetts. Because bedrock is so shallow beneath this aquifer (maximum depth is 30 m), the depth-integrated mass deficiency of the overlying unconsolidated material was small, so that the observed gravity anomaly was on the order of 1 milligal (mGal) or less. Thus data uncertainties were significant. Moreover, unlike previous gravity studies elsewhere, we had no a priori information on the density of the sediment. Under such circumstances, it is essential to include model constraints and weighted least-squares in the inversion procedure. Among the model constraints were water table configuration, bedrock outcrops, and depth to bedrock from five water wells. Our procedure allowed us to delineate depth to bedrock along a 3.5 km profile with a confidence interval of 1.8 m at a nominal depth of 17 m. Moreover, we obtained a porosity estimate in the range of 39% to 44%. Thus the gravity method, with appropriate refinements, is an effective tool for the reconnaissance of shallow unconfined aquifers.

  5. BACTERIA SOURCE TRACKING AND HOST SPECIES SPECIFICITY ANALYSIS

    EPA Science Inventory

    Point and non-point pollution sources of fecal pollution on a watershed adversely impact the quality of drinking source waters and recreational waters. States are required to develop total maximum daily loads (TMDLs) and devise best management practices (BMPs) to reduce the pollu...

  6. DNA BASED MOLECULAR METHODS FOR BACTERIAL SOURCE TRACKING IN WATERSHEDS

    EPA Science Inventory

    Point and non-point pollution sources of fecal pollution on a watershed adversely impact the quality of drinking source waters and recreational waters. States are required to develop total maximum daily loads (TMDLs) and devise best management practices (BMPs) to reduce the po...

  7. Area Source Emission Measurements Using EPA OTM 10

    EPA Science Inventory

    Measurement of air pollutant emissions from area and non-point sources is an emerging environmental concern. Due to the spatial extent and non-homogenous nature of these sources, assessment of fugitive emissions using point sampling techniques can be difficult. To help address th...

  8. Semi-automatic delineation using weighted CT-MRI registered images for radiotherapy of nasopharyngeal cancer

    SciTech Connect

    Fitton, I.; Cornelissen, S. A. P.; Duppen, J. C.; Rasch, C. R. N.; Herk, M. van; Steenbakkers, R. J. H. M.; Peeters, S. T. H.; Hoebers, F. J. P.; Kaanders, J. H. A. M.; Nowak, P. J. C. M.

    2011-08-15

    Purpose: To develop a delineation tool that refines physician-drawn contours of the gross tumor volume (GTV) in nasopharynx cancer, using combined pixel value information from x-ray computed tomography (CT) and magnetic resonance imaging (MRI) during delineation. Methods: Operator-guided delineation assisted by a so-called ''snake'' algorithm was applied on weighted CT-MRI registered images. The physician delineates a rough tumor contour that is continuously adjusted by the snake algorithm using the underlying image characteristics. The algorithm was evaluated on five nasopharyngeal cancer patients. Different linear weightings CT and MRI were tested as input for the snake algorithm and compared according to contrast and tumor to noise ratio (TNR). The semi-automatic delineation was compared with manual contouring by seven experienced radiation oncologists. Results: A good compromise for TNR and contrast was obtained by weighing CT twice as strong as MRI. The new algorithm did not notably reduce interobserver variability, it did however, reduce the average delineation time by 6 min per case. Conclusions: The authors developed a user-driven tool for delineation and correction based a snake algorithm and registered weighted CT image and MRI. The algorithm adds morphological information from CT during the delineation on MRI and accelerates the delineation task.

  9. Surface geophysical techniques for aquifer and wellhead protection area delineation. Technical report (Final)

    SciTech Connect

    Violette, P.

    1987-12-01

    Surface geophysical techniques developed by the petroleum and minerals industries are applicable to ground-water investigations. This document examines some of these techniques to aid in the delineation of aquifers as part of the delineation of wellhead protection areas. Overviewed are seismic, electrical, electromagnetic induction, VLF resistivity, ground penetrating radar, gravity, and magnetic geophysical techniques, and their applicability to aquifer delineation. The theory and methodology of these are discussed, along with the method costs as of early 1987. Also briefly discussed is the delineation of wellhead protection areas.

  10. Basin delineation and identification of nitrogen sources in an urban watershed

    EPA Science Inventory

    Nutrient pollution in stormwater runoff from urbanized areas contributes to water quality degradation in streams and receiving waterbodies. Increased nitrogen loading from human activities stimulates eutrophication through algal blooms, which leads to an overall decrease in drink...

  11. Catchment delineation and morphometric analysis using geographical information system.

    PubMed

    Kumar, Manoj; Kumar, Rohitashw; Singh, P K; Singh, Manjeet; Yadav, K K; Mittal, H K

    2015-01-01

    The geographical information system (GIS) has emerged as an efficient tool in delineation of drainage patterns of watershed planning and management. The morphometric parameters of basins can address linear, areal and relief aspects. The study deals with the integrated watershed management of Baliya micro-watersheds, located in the Udaipur district of Rajasthan, India. Morphometric analysis in hydrological investigation is an important aspect and it is inevitable in the development and management of drainage basins. The determination of linear, areal and relief parameters indicate fairly good significance. The low value of the bifurcation ratio of 4.19 revealed that the drainage pattern has not been distorted by structural disturbance. The high value of the elongation ratio (0.68) compared to the circulatory ratio (0.27) indicates an elongated shape of the watershed. The high value of drainage density (5.39 km/km(2)) and stream frequency (12.32) shows that the region has impermeable subsoil material under poor vegetative cover with a low relief factor. The morphometric parameters of relief ratio (0.041) and relative relief (0.99%) show that the watershed can be treated using GIS techniques to determine the morphometric presence of dendritic drainage pattern, with a view to selecting the soil and water conservation measures and water harvesting.

  12. Automatic delineation of the diaphragm in computed tomographic images.

    PubMed

    Rangayyan, Rangaraj M; Vu, Randy H; Boag, Graham S

    2008-10-01

    Segmentation of the internal organs in medical images is a difficult task. By incorporating a priori information regarding specific organs of interest, results of segmentation may be improved. Landmarking (i.e., identifying stable structures to aid in gaining more knowledge concerning contiguous structures) is a promising segmentation method. Specifically, segmentation of the diaphragm may help in limiting the scope of segmentation methods to the abdominal cavity; the diaphragm may also serve as a stable landmark for identifying internal organs, such as the liver, the spleen, and the heart. A method to delineate the diaphragm is proposed in the present work. The method is based upon segmentation of the lungs, identification of the lower surface of the lungs as an initial representation of the diaphragm, and the application of least-squares modeling and deformable contour models to obtain the final segmentation of the diaphragm. The proposed procedure was applied to nine X-ray computed tomographic (CT) exams of four pediatric patients with neuroblastoma. The results were evaluated against the boundaries of the diaphragm as identified independently by a radiologist. Good agreement was observed between the results of segmentation and the reference contours drawn by the radiologist, with an average mean distance to the closest point of 5.85 mm over a total of 73 CT slices including the diaphragm.

  13. Directional phytoscreening: contaminant gradients in trees for plume delineation.

    PubMed

    Limmer, Matt A; Shetty, Mikhil K; Markus, Samantha; Kroeker, Ryan; Parker, Beth L; Martinez, Camilo; Burken, Joel G

    2013-08-20

    Tree sampling methods have been used in phytoscreening applications to delineate contaminated soil and groundwater, augmenting traditional investigative methods that are time-consuming, resource-intensive, invasive, and costly. In the past decade, contaminant concentrations in tree tissues have been shown to reflect the extent and intensity of subsurface contamination. This paper investigates a new phytoscreening tool: directional tree coring, a concept originating from field data that indicated azimuthal concentrations in tree trunks reflected the concentration gradients in the groundwater around the tree. To experimentally test this hypothesis, large diameter trees were subjected to subsurface contaminant concentration gradients in a greenhouse study. These trees were then analyzed for azimuthal concentration gradients in aboveground tree tissues, revealing contaminant centroids located on the side of the tree nearest the most contaminated groundwater. Tree coring at three field sites revealed sufficiently steep contaminant gradients in trees reflected nearby groundwater contaminant gradients. In practice, trees possessing steep contaminant gradients are indicators of steep subsurface contaminant gradients, providing compass-like information about the contaminant gradient, pointing investigators toward higher concentration regions of the plume.

  14. Delineation of modular proteins: domain boundary prediction from sequence information.

    PubMed

    Kong, Lesheng; Ranganathan, Shoba

    2004-06-01

    The delineation of domain boundaries of a given sequence in the absence of known 3D structures or detectable sequence homology to known domains benefits many areas in protein science, such as protein engineering, protein 3D structure determination and protein structure prediction. With the exponential growth of newly determined sequences, our ability to predict domain boundaries rapidly and accurately from sequence information alone is both essential and critical from the viewpoint of gene function annotation. Anyone attempting to predict domain boundaries for a single protein sequence is invariably confronted with a plethora of databases that contain boundary information available from the internet and a variety of methods for domain boundary prediction. How are these derived and how well do they work? What definition of 'domain' do they use? We will first clarify the different definitions of protein domains, and then describe the available public databases with domain boundary information. Finally, we will review existing domain boundary prediction methods and discuss their strengths and weaknesses.

  15. Delineation of groundwater potential zone: An AHP/ANP approach

    NASA Astrophysics Data System (ADS)

    Agarwal, Etishree; Agarwal, Rajat; Garg, R. D.; Garg, P. K.

    2013-06-01

    The sustainable development and management of groundwater resource requires precise quantitative assessment based on scientific principle and modern techniques. In the present study, groundwater potential zone are delineated using remote sensing, geographical information system (GIS) and multi-criteria decision making (MCDM) techniques in Unnao district, Uttar Pradesh. The analytical network process (ANP) is a method that makes it possible for one to deal systematically, and includes the analytical hierarchy process (AHP) as a special case. The AHP and ANP are used to determine the weights of various themes and their classes for identifying the groundwater potential zone. These weights are applied in a linear combination to obtain five different groundwater potential zone in the study area, namely `very poor', `poor', `moderate', `good' and `very good'. It has been concluded that about 153.39 km2 area has very good groundwater potential which is only 3.37% of the total study area. However, the area having very poor groundwater potential is about 850 km2 which is about 19.63% of the study area. The area having good, moderate and poor groundwater potential is about 540.25, 1135.5, 1868.6 km2, respectively. The groundwater potential zone map was finally verified using the well yield data of 37 pumping wells, and the result was found satisfactory.

  16. Volcanic calderas delineate biogeographic provinces among Yellowstone thermophiles.

    PubMed

    Takacs-Vesbach, Cristina; Mitchell, Kendra; Jackson-Weaver, Olan; Reysenbach, Anna-Louise

    2008-07-01

    It has been suggested that the distribution of microorganisms should be cosmopolitan because of their enormous capacity for dispersal. However, recent studies have revealed that geographically isolated microbial populations do exist. Geographic distance as a barrier to dispersal is most often invoked to explain these distributions. Here we show that unique and diverse sequences of the bacterial genus Sulfurihydrogenibium exist in Yellowstone thermal springs, indicating that these sites are geographically isolated. Although there was no correlation with geographic distance or the associated geochemistry of the springs, there was a strong historical signal. We found that the Yellowstone calderas, remnants of prehistoric volcanic eruptions, delineate biogeographical provinces for the Sulfurihydrogenibium within Yellowstone (chi(2): 9.7, P = 0.002). The pattern of distribution that we have detected suggests that major geological events in the past 2 million years explain more of the variation in sequence diversity in this system than do contemporary factors such as habitat or geographic distance. These findings highlight the importance of historical legacies in determining contemporary microbial distributions and suggest that the same factors that determine the biogeography of macroorganisms are also evident among bacteria.

  17. Hornblendite delineates zones of mass transfer through the lower crust

    PubMed Central

    Daczko, Nathan R.; Piazolo, Sandra; Meek, Uvana; Stuart, Catherine A.; Elliott, Victoria

    2016-01-01

    Geochemical signatures throughout the layered Earth require significant mass transfer through the lower crust, yet geological pathways are under-recognized. Elongate bodies of basic to ultrabasic rocks are ubiquitous in exposures of the lower crust. Ultrabasic hornblendite bodies hosted within granulite facies gabbroic gneiss of the Pembroke Valley, Fiordland, New Zealand, are typical occurrences usually reported as igneous cumulate hornblendite. Their igneous features contrast with the metamorphic character of their host gabbroic gneiss. Both rock types have a common parent; field relationships are consistent with modification of host gabbroic gneiss into hornblendite. This precludes any interpretation involving cumulate processes in forming the hornblendite; these bodies are imposter cumulates. Instead, replacement of the host gabbroic gneiss formed hornblendite as a result of channeled high melt flux through the lower crust. High melt/rock ratios and disequilibrium between the migrating magma (granodiorite) and its host gabbroic gneiss induced dissolution (grain-scale magmatic assimilation) of gneiss and crystallization of mainly hornblende from the migrating magma. The extent of this reaction-replacement mechanism indicates that such hornblendite bodies delineate significant melt conduits. Accordingly, many of the ubiquitous basic to ultrabasic elongate bodies of the lower crust likely map the ‘missing’ mass transfer zones. PMID:27546342

  18. Hornblendite delineates zones of mass transfer through the lower crust.

    PubMed

    Daczko, Nathan R; Piazolo, Sandra; Meek, Uvana; Stuart, Catherine A; Elliott, Victoria

    2016-08-22

    Geochemical signatures throughout the layered Earth require significant mass transfer through the lower crust, yet geological pathways are under-recognized. Elongate bodies of basic to ultrabasic rocks are ubiquitous in exposures of the lower crust. Ultrabasic hornblendite bodies hosted within granulite facies gabbroic gneiss of the Pembroke Valley, Fiordland, New Zealand, are typical occurrences usually reported as igneous cumulate hornblendite. Their igneous features contrast with the metamorphic character of their host gabbroic gneiss. Both rock types have a common parent; field relationships are consistent with modification of host gabbroic gneiss into hornblendite. This precludes any interpretation involving cumulate processes in forming the hornblendite; these bodies are imposter cumulates. Instead, replacement of the host gabbroic gneiss formed hornblendite as a result of channeled high melt flux through the lower crust. High melt/rock ratios and disequilibrium between the migrating magma (granodiorite) and its host gabbroic gneiss induced dissolution (grain-scale magmatic assimilation) of gneiss and crystallization of mainly hornblende from the migrating magma. The extent of this reaction-replacement mechanism indicates that such hornblendite bodies delineate significant melt conduits. Accordingly, many of the ubiquitous basic to ultrabasic elongate bodies of the lower crust likely map the 'missing' mass transfer zones.

  19. Delineating liver events in trichloroethylene-induced autoimmune hepatitis.

    PubMed

    Gilbert, Kathleen M; Przybyla, Beata; Pumford, Neil R; Han, Tao; Fuscoe, James; Schnackenberg, Laura K; Holland, Ricky D; Doss, Jason C; Macmillan-Crow, Lee Ann; Blossom, Sarah J

    2009-04-01

    Exposure to the environmental pollutant trichloroethylene (TCE) has been linked to autoimmune disease development in humans. Chronic (32-week) low-level exposure to TCE has been shown to promote autoimmune hepatitis in association with CD4(+) T cell activation in autoimmune-prone MRL+/+ mice. MRL+/+ mice are usually thought of as a model of systemic lupus rather than an organ-specific disease such as autoimmune hepatitis. Consequently, the present study examined gene expression and metabolites to delineate the liver events that skewed the autoimmune response toward that organ in TCE-treated mice. Female MRL+/+ mice were treated with 0.5 mg/mL TCE in their drinking water. The results showed that TCE-induced autoimmune hepatitis could be detected in as little as 26 weeks. TCE exposure also generated a time-dependent increase in the number of antibodies specific for liver proteins. The gene expression correlated with the metabolite analysis to show that TCE upregulated the methionine/homocysteine pathway in the liver after 26 weeks of exposure. The results also showed that TCE exposure altered the expression of selective hepatic genes associated with immunity and inflammation. On the basis of these results, future mechanistic studies will focus on how alterations in genes associated with immunity and inflammation, in conjunction with protein alterations in the liver, promote liver immunogenicity in TCE-treated MRL+/+ mice.

  20. Delineation of Steroid-Degrading Microorganisms through Comparative Genomic Analysis

    PubMed Central

    Bergstrand, Lee H.; Cardenas, Erick; Holert, Johannes; Van Hamme, Jonathan D.

    2016-01-01

    ABSTRACT Steroids are ubiquitous in natural environments and are a significant growth substrate for microorganisms. Microbial steroid metabolism is also important for some pathogens and for biotechnical applications. This study delineated the distribution of aerobic steroid catabolism pathways among over 8,000 microorganisms whose genomes are available in the NCBI RefSeq database. Combined analysis of bacterial, archaeal, and fungal genomes with both hidden Markov models and reciprocal BLAST identified 265 putative steroid degraders within only Actinobacteria and Proteobacteria, which mainly originated from soil, eukaryotic host, and aquatic environments. These bacteria include members of 17 genera not previously known to contain steroid degraders. A pathway for cholesterol degradation was conserved in many actinobacterial genera, particularly in members of the Corynebacterineae, and a pathway for cholate degradation was conserved in members of the genus Rhodococcus. A pathway for testosterone and, sometimes, cholate degradation had a patchy distribution among Proteobacteria. The steroid degradation genes tended to occur within large gene clusters. Growth experiments confirmed bioinformatic predictions of steroid metabolism capacity in nine bacterial strains. The results indicate there was a single ancestral 9,10-seco-steroid degradation pathway. Gene duplication, likely in a progenitor of Rhodococcus, later gave rise to a cholate degradation pathway. Proteobacteria and additional Actinobacteria subsequently obtained a cholate degradation pathway via horizontal gene transfer, in some cases facilitated by plasmids. Catabolism of steroids appears to be an important component of the ecological niches of broad groups of Actinobacteria and individual species of Proteobacteria. PMID:26956583

  1. Delineation of the movement disorders associated with FOXG1 mutations

    PubMed Central

    Papandreou, Apostolos; Schneider, Ruth B.; Augustine, Erika F.; Ng, Joanne; Mankad, Kshitij; Meyer, Esther; McTague, Amy; Ngoh, Adeline; Hemingway, Cheryl; Robinson, Robert; Varadkar, Sophia M.; Kinali, Maria; Salpietro, Vincenzo; O'Driscoll, Margaret C.; Basheer, S. Nigel; Webster, Richard I.; Mohammad, Shekeeb S.; Pula, Shpresa; McGowan, Marian; Trump, Natalie; Jenkins, Lucy; Elmslie, Frances; Scott, Richard H.; Hurst, Jane A.; Perez-Duenas, Belen; Paciorkowski, Alexander R.

    2016-01-01

    Objective: The primary objective of this research was to characterize the movement disorders associated with FOXG1 mutations. Methods: We identified patients with FOXG1 mutations who were referred to either a tertiary movement disorder clinic or tertiary epilepsy service and retrospectively reviewed medical records, clinical investigations, neuroimaging, and available video footage. We administered a telephone-based questionnaire regarding the functional impact of the movement disorders and perceived efficacy of treatment to the caregivers of one cohort of participants. Results: We identified 28 patients with FOXG1 mutations, of whom 6 had previously unreported mutations. A wide variety of movement disorders were identified, with dystonia, choreoathetosis, and orolingual/facial dyskinesias most commonly present. Ninety-three percent of patients had a mixed movement disorder phenotype. In contrast to the phenotype classically described with FOXG1 mutations, 4 patients with missense mutations had a milder phenotype, with independent ambulation, spoken language, and normocephaly. Hyperkinetic involuntary movements were a major clinical feature in these patients. Of the symptomatic treatments targeted to control abnormal involuntary movements, most did not emerge as clearly beneficial, although 4 patients had a caregiver-reported response to levodopa. Conclusions: Abnormal involuntary movements are a major feature of FOXG1 mutations. Our study delineates the spectrum of movement disorders and confirms an expanding clinical phenotype. Symptomatic treatment may be considered for severe or disabling cases, although further research regarding potential treatment strategies is necessary. PMID:27029630

  2. Hornblendite delineates zones of mass transfer through the lower crust

    NASA Astrophysics Data System (ADS)

    Daczko, Nathan R.; Piazolo, Sandra; Meek, Uvana; Stuart, Catherine A.; Elliott, Victoria

    2016-08-01

    Geochemical signatures throughout the layered Earth require significant mass transfer through the lower crust, yet geological pathways are under-recognized. Elongate bodies of basic to ultrabasic rocks are ubiquitous in exposures of the lower crust. Ultrabasic hornblendite bodies hosted within granulite facies gabbroic gneiss of the Pembroke Valley, Fiordland, New Zealand, are typical occurrences usually reported as igneous cumulate hornblendite. Their igneous features contrast with the metamorphic character of their host gabbroic gneiss. Both rock types have a common parent; field relationships are consistent with modification of host gabbroic gneiss into hornblendite. This precludes any interpretation involving cumulate processes in forming the hornblendite; these bodies are imposter cumulates. Instead, replacement of the host gabbroic gneiss formed hornblendite as a result of channeled high melt flux through the lower crust. High melt/rock ratios and disequilibrium between the migrating magma (granodiorite) and its host gabbroic gneiss induced dissolution (grain-scale magmatic assimilation) of gneiss and crystallization of mainly hornblende from the migrating magma. The extent of this reaction-replacement mechanism indicates that such hornblendite bodies delineate significant melt conduits. Accordingly, many of the ubiquitous basic to ultrabasic elongate bodies of the lower crust likely map the ‘missing’ mass transfer zones.

  3. DNA Probe Pooling for Rapid Delineation of Chromosomal Breakpoints

    SciTech Connect

    Lu, Chun-Mei; Kwan, Johnson; Baumgartner, Adolf; Weier, Jingly F.; Wang, Mei; Escudero, Tomas; Munne', Santiago; Zitzelsberger, Horst F.; Weier, Heinz-Ulrich

    2009-01-30

    Structural chromosome aberrations are hallmarks of many human genetic diseases. The precise mapping of translocation breakpoints in tumors is important for identification of genes with altered levels of expression, prediction of tumor progression, therapy response, or length of disease-free survival as well as the preparation of probes for detection of tumor cells in peripheral blood. Similarly, in vitro fertilization (IVF) and preimplantation genetic diagnosis (PGD) for carriers of balanced, reciprocal translocations benefit from accurate breakpoint maps in the preparation of patient-specific DNA probes followed by a selection of normal or balanced oocytes or embryos. We expedited the process of breakpoint mapping and preparation of case-specific probes by utilizing physically mapped bacterial artificial chromosome (BAC) clones. Historically, breakpoint mapping is based on the definition of the smallest interval between proximal and distal probes. Thus, many of the DNA probes prepared for multi-clone and multi-color mapping experiments do not generate additional information. Our pooling protocol described here with examples from thyroid cancer research and PGD accelerates the delineation of translocation breakpoints without sacrificing resolution. The turnaround time from clone selection to mapping results using tumor or IVF patient samples can be as short as three to four days.

  4. New insight into the correlations between land use and water quality in a coastal watershed of China: Does point source pollution weaken it?

    PubMed

    Zhou, Pei; Huang, Jinliang; Pontius, Robert Gilmore; Hong, Huasheng

    2016-02-01

    Uncovering the associations between land use and river water quality is useful for managing land-based pollution in the catchment-coast continuum. However, it is not clear how land use affects water quality in the context of simultaneous point source (PS) pollution. In this study, we develop a self-organizing map (SOM)-based approach to explore the relationship between land use and water quality in the Minjiang River Watershed, Southeast China. Water samples from 139 headwater sub-watersheds were associated with six land use categories, namely, Woodland, Agriculture, Orchard, Built-up, Unused land and Water. Sampling sites are delineated into six clusters based on six water quality parameters: ammonium-N, nitrate-N, total nitrogen, soluble reactive phosphate, total phosphate and potassium permanganate index. Local relationships between land use and water quality among four clusters that have sufficient sample sizes are further identified. There is no significant land use-water quality correlation in one of the four clusters (including 37 sub-watersheds). And the greater the PS pollution is, the less significant the land use-water quality correlations are in clusters. The results demonstrate how PS pollution weakens the land use-water quality correlation. Our method can help to determine whether non-point source or PS pollution exerts greater influence on the quality of the water coming from watershed.

  5. Delineating Landfill Leachate Discharge To An Arsenic Contaminated Waterway

    EPA Science Inventory

    Discharge of contaminated ground water may serve as a primary and on-going source of contamination to surface water. A field investigation was conducted at a Superfund site in Massachusetts, USA to define the locus of contaminant flux and support source identification for arseni...

  6. Integrated semi-automated landslide delineation, classification and evaluation

    NASA Astrophysics Data System (ADS)

    Hölbling, Daniel; Eisank, Clemens; Friedl, Barbara; Blaschke, Thomas

    2013-04-01

    Landslides constitute a major natural hazard in almost all mountainous regions of the world. Today, the wide range of available Earth Observation (EO) data implies the need for reliable and efficient methods for detecting, analysing and monitoring landslides in order to assist hazard and risk analysis. Hence, it is of high importance to make use of effective techniques in order to gather information about the exact location, extent and type of landslides in a fast and transparent manner. Object-based image analysis (OBIA) provides a great potential for semi-automated landslide detection and classification, since - in comparison to pixel-based approaches - not only spectral, but also spatial, morphometric, textural, as well as contextual properties can be addressed. Through the integration of multiple data sets landslides can be examined in a more efficient way, making use of the most suitable properties of the available information layers. Within the project "iSLIDE - Integrated Semi-automated Landslide Delineation, Classification and Evaluation", funded by the Austrian Science Found (FWF), we address such issues by developing a methodological framework for landslide delineation, classification and evaluation through the integration of optical remote sensing data and digital elevation information, as well as terrain unit layers using innovative OBIA methods. Additionally, the potential of SAR data for object-based landslide mapping will be investigated. The methodology will be developed and tested in Austrian as well as Taiwanese study areas, which are frequently affected by landslides. An important component of the framework is the definition of digital signatures of landslide types that facilitate the transformation of expert knowledge into machine-understandable rules. Such a conceptual foundation will make the approach robust and transferable to other study areas, en route to fully automated landslide analysis. Furthermore, the development of automated object

  7. Delineating relative homogeneous G+C domains in DNA sequences.

    PubMed

    Li, W

    2001-10-03

    The concept of homogeneity of G+C content is always relative and subjective. This point is emphasized and quantified in this paper using a simple example of one sequence segmented into two subsequences. Whether the sequence is homogeneous or not can be answered by whether the two-subsequence model describes the DNA sequence better than the one-sequence model. There are at least three equivalent ways of looking at the 1-to-2 segmentation: Jensen-Shannon divergence measure, log likelihood ratio test, and model selection using Bayesian information criterion. Once a criterion is chosen, a DNA sequence can be recursively segmented into multiple domains. We use one subjective criterion called segmentation strength based on the Bayesian information criterion. Whether or not a sequence is homogeneous and how many domains it has depend on this criterion. We compare six different genome sequences (yeast S. cerevisiae chromosome III and IV, bacterium M. pneumoniae, human major histocompatibility complex sequence, longest contigs in human chromosome 21 and 22) by recursive segmentations at different strength criteria. Results by recursive segmentation confirm that yeast chromosome IV is more homogeneous than yeast chromosome III, human chromosome 21 is more homogeneous than human chromosome 22, and bacterial genomes may not be homogeneous due to short segments with distinct base compositions. The recursive segmentation also provides a quantitative criterion for identifying isochores in human sequences. Some features of our recursive segmentation, such as the possibility of delineating domain borders accurately, are superior to those of the moving-window approach commonly used in such analyses.

  8. Comprehensive multiplexed protein quantitation delineates eosinophilic and neutrophilic experimental asthma

    PubMed Central

    2014-01-01

    Background Improvements in asthma diagnosis and management require deeper understanding of the heterogeneity of the complex airway inflammation. We hypothesise that differences in the two major inflammatory phenotypes of asthma; eosinophilic and neutrophilic asthma, will be reflected in the lung protein expression profile of murine asthma models and can be delineated using proteomics of bronchoalveolar lavage (BAL). Methods BAL from mice challenged with ovalbumin (OVA/OVA) alone (standard model of asthma, here considered eosinophilic) or OVA in combination with endotoxin (OVA/LPS, model of neutrophilic asthma) was analysed using liquid chromatography coupled to high resolution mass spectrometry, and compared with steroid-treated animals and healthy controls. In addition, conventional inflammatory markers were analysed using multiplexed ELISA (Bio-Plex™ assay). Multivariate statistics was performed on integrative proteomic fingerprints using principal component analysis. Proteomic data were complemented with lung mechanics and BAL cell counts. Results Several of the analysed proteins displayed significant differences between the controls and either or both of the two models reflecting eosinophilic and neutrophilic asthma. Most of the proteins found with mass spectrometry analysis displayed a considerable increase in neutrophilic asthma compared with the other groups. Conversely, the larger number of the inflammatory markers analysed with Bio-Plex™ analysis were found to be increased in the eosinophilic model. In addition, major inflammation markers were correlated to peripheral airway closure, while commonly used asthma biomarkers only reflect central inflammation. Conclusion Our data suggest that the commercial markers we are currently relying on to diagnose asthma subtypes are not giving us comprehensive or specific enough information. The analysed protein profiles allowed to discriminate the two models and may add useful information for characterization of

  9. Delineating and quantifying ground water discharge zones using streambed temperatures.

    PubMed

    Conant, Brewster

    2004-01-01

    Streambed temperature mapping, hydraulic testing using minipiezometers, and geochemical analyses of interstitial water of the streambed were used to delineate the pattern of ground water discharge in a sandy streambed and to develop a flux-based conceptual model for ground water/surface water interactions. A new and simple empirical method was used to relate fluxes obtained from minipiezometer data to streambed temperatures. The relationship allowed flux to be calculated at locations where only streambed temperature measurements were made. Slug testing and potentiomanometer measurements at 34 piezometers indicated ground water discharge ranged from 0.03 to 446 L/m2/day (and possibly as high as 7060 L/m2/day) along a 60 m long by 11 to 14 m wide reach of river. Complex but similar plan-view patterns of flux were calculated for both summer and winter using hundreds of streambed temperatures measured on a 1 by 2 m grid. The reach was dominated by ground water discharge and 5% to 7% of the area accounted for approximately 20% to 24% of the total discharge. < 12% of the total area consisted of recharge zones or no-discharge zones. A conceptual model for ground water/surface water interactions consisting of five different behaviors was developed based on the magnitude and direction of flux across the surface of the streambed. The behaviors include short-circuit discharge (e.g., high-flow springs), high discharge (e.g., preferential flowpaths), low to moderate discharge, no discharge (e.g., horizontal hyporheic or ground water flow), and recharge. Geological variations at depth played a key role in determining which type of flow behavior occurred in the streambed.

  10. Glacial Delineation and Ice Retreat on Pico de Orizaba, Mexico

    NASA Astrophysics Data System (ADS)

    Colby, A. E.; Weissling, B.; Xie, H.

    2011-12-01

    Pico de Orizaba, a dormant stratovolcano at the eastern end of the Trans-Mexican Volcanic Belt at approximately 19 degrees of latitude and the third largest peak in North America (5636 m), hosts what is likely the last significant tropical zone glacier (Jamapa Glacier) in the Northern Hemisphere. Not since the International Geophysical Year of 1957-58 has Pico's glacial environment been studied with any focused effort, perhaps due to the general innaccessibility, high altitude, and steep slopes. As are most glaciers around the world, the Jamapa Glacier is retreating, with a remarkable loss of ice in the past 2 decades. The rate and pattern of retreat is important to understanding climate change forcing as well as understanding environmental and water supply impacts to a substantial human population who live along the base of the volcano. Through the use of satellite imagery (LandSat, ASTER, IKONOS), legacy hand-drawn maps, aerial photographs, and first-hand accounts from climber's expeditions, a reasonably accurate map of almost 60 years of glacial retreat has been produced. Legacy hand-drawn maps of the ice edge, that pre-date the satellite era, did not fit perfectly with modern images when layered in ArcGIS. Oblique perspectives in Google Earth and various aerial and surface-based photographs of the mountain were used to help fit the ice edge to the actual topography. The disparity of satellite image pixel resolution (from 1 m IKONOS to 60 m LandSat) was addressed using various imagery analysis tools (eg. edge detection convolution filters and pixel unmixing) in order to delineate an approximate ice edge for the respective image date. The final map shows the nature of ice edge retreat on Pico de Orizaba from 1945 up until the present (Feb 2011).

  11. Delineation of the calcineurin-interacting region of cyclophilin B.

    PubMed Central

    Carpentier, M.; Allain, F.; Haendler, B.; Slomianny, M. C.; Spik, G.

    2000-01-01

    The immunosuppressant drug cyclosporin A (CsA) inhibits T-cell function by blocking the phosphatase activity of calcineurin. This effect is mediated by formation of a complex between the drug and cyclophilin (CyP), which creates a composite surface able to make high-affinity contacts with calcineurin. In vitro, the CyPB/CsA complex is more effective in inhibiting calcineurin than the CyPA/CsA and CyPC/CsA complexes, pointing to fine structural differences in the calcineurin-binding region. To delineate the calcineurin-binding region of CyPB, we mutated several amino acids, located in two loops corresponding to CyPA regions known to be involved, as follows: R76A, G77H, D155R, and D158R. Compared to wild-type CyPB, the G77H, D155R, and D158R mutants had intact isomerase and CsA-binding activities, indicating that no major conformational changes had taken place. When complexed to CsA, they all displayed only reduced affinity for calcineurin and much decreased inhibition of calcineurin phosphatase activity. These results strongly suggest that the three amino acids G77, D155, and D158 are directly involved in the interaction of CyPB/CsA with calcineurin, in agreement with their exposed position. The G77, D155, and D158 residues are not maintained in CyPA and might therefore account for the higher affinity of the CyPB/CsA complex for calcineurin. PMID:11206060

  12. Microbial Source Module (MSM): Documenting the Science and Software for Discovery, Evaluation, and Integration

    EPA Science Inventory

    The Microbial Source Module (MSM) estimates microbial loading rates to land surfaces from non-point sources, and to streams from point sources for each subwatershed within a watershed. A subwatershed, the smallest modeling unit, represents the common basis for information consume...

  13. Using satellite radiotelemetry data to delineate and manage wildlife populations

    USGS Publications Warehouse

    Amstrup, Steven C.; McDonald, T.L.; Durner, G.M.

    2004-01-01

    the Chukchi Sea population and 50% from the Southern Beaufort Sea population. At Tuktoyaktuk, Northwest Territories, Canada, 50% are from the Southern Beaufort Sea and 50% from the Northern Beaufort Sea population. The methods described here will aid managers of all wildlife that can be studied by telemetry to allocate harvests and other human perturbations to the appropriate populations, make risk assessments, and predict impacts of human activities. They will aid researchers by providing the refined descriptions of study populations that are necessary for population estimation and other investigative tasks. Arctic, Beaufort Sea, boundaries, clustering, Fourier transform, kernel, management, polar bears, population delineation, radiotelemetry, satellite, smoothing, Ursus maritimus

  14. Delineating copper accumulation pathways for the freshwater bivalve Corbicula using stable copper isotopes

    USGS Publications Warehouse

    Croteau, M.-N.; Luoma, S.N.

    2005-01-01

    Delineation of metal uptake routes in aquatic invertebrates is critical for characterizing bioaccumulation dynamics and assessing risks associated with metal exposure. Here we demonstrate that Cu stable isotopic ratios can be manipulated in both exposure media and algae to determine the efflux rate constant (ke) and to estimate Cu assimilation efficiency (AE) from ingested food in a freshwater bivalve (Corbicula fluminea). The Cu AE in Corhicula fed 65Cu-spiked Cryptomonas ozolini was 38%. Copper uptake routes had no significant influence on efflux; ke, of 0.004 per day characterized the slowest component of efflux following short-term exposures to 65Cu in water or in both food and water. Incorporation of the physiological parameters for dietary and dissolved uptake as well as rate constants of loss into a bioaccumulation model allowed for assessing the relative contribution of water and food as Cu sources. At [65Cu 2+] of 6.7 ??g/L, Corbicula accumulated twice as much Cu from diet as from water. In most freshwater systems, the dietary pathway is likely to act as the major Cu uptake route for Corbicula. Extrapolation of our laboratory results to the San Francisco Bay-Delta (California, USA) indicated that our biodynamic model and the laboratory-derived parameters for dietary 65Cu uptake provided a realistic representation of the processes involved in Cu accumulation by the bivalve Corbicula. ?? 2005 SETAC.

  15. Delineation of subsurface hydrocarbon contamination at a former hydrogenation plant using spectral induced polarization imaging.

    PubMed

    Flores Orozco, Adrián; Kemna, Andreas; Oberdörster, Christoph; Zschornack, Ludwig; Leven, Carsten; Dietrich, Peter; Weiss, Holger

    2012-08-01

    Broadband spectral induced polarization (SIP) measurements were conducted at a former hydrogenation plant in Zeitz (NE Germany) to investigate the potential of SIP imaging to delineate areas with different BTEX (benzene, toluene, ethylbenzene, and xylene) concentrations. Conductivity images reveal a poor correlation with the distribution of contaminants; whereas phase images exhibit two main anomalies: low phase shift values (<5 mrad) for locations with high BTEX concentrations, including the occurrence of free-phase product (BTEX concentrations >1.7 g/l), and higher phase values for lower BTEX concentrations. Moreover, the spectral response of the areas with high BTEX concentration and free-phase products reveals a flattened spectrum in the low frequencies (<40 Hz), while areas with lower BTEX concentrations exhibit a response characterized by a frequency peak. The SIP response was modelled using a Debye decomposition to compute images of the median relaxation-time. Consistent with laboratory studies, we observed an increase in the relaxation-time associated with an increase in BTEX concentrations. Measurements were also collected in the time domain (TDIP), revealing imaging results consistent with those obtained for frequency domain (SIP) measurements. Results presented here demonstrate the potential of the SIP imaging method to discriminate source and plume of dissolved contaminants at BTEX contaminated sites.

  16. Delineation of estuarine management areas using multivariate geostatistics: the case of Sado Estuary.

    PubMed

    Caeiro, Sandra; Goovaerts, Pierre; Painho, Marco; Costa, M Helena

    2003-09-15

    The Sado Estuary is a coastal zone located in the south of Portugal where conflicts between conservation and development exist because of its location near industrialized urban zones and its designation as a natural reserve. The aim of this paper is to evaluate a set of multivariate geostatistical approaches to delineate spatially contiguous regions of sediment structure for Sado Estuary. These areas will be the supporting infrastructure of an environmental management system for this estuary. The boundaries of each homogeneous area were derived from three sediment characterization attributes through three different approaches: (1) cluster analysis of dissimilarity matrix function of geographical separation followed by indicator kriging of the cluster data, (2) discriminant analysis of kriged values of the three sediment attributes, and (3) a combination of methods 1 and 2. Final maximum likelihood classification was integrated into a geographical information system. All methods generated fairly spatially contiguous management areas that reproduce well the environment of the estuary. Map comparison techniques based on kappa statistics showed thatthe resultant three maps are similar, supporting the choice of any of the methods as appropriate for management of the Sado Estuary. However, the results of method 1 seem to be in better agreement with estuary behavior, assessment of contamination sources, and previous work conducted at this site.

  17. Delineating Area of Review in a System with Pre-injection Relative Overpressure

    DOE PAGES

    Oldenburg, Curtis M.; Cihan, Abdullah; Zhou, Quanlin; ...

    2014-12-31

    The Class VI permit application for geologic carbon sequestration (GCS) requires delineation of an area of review (AoR), defined as the region surrounding the (GCS) project where underground sources of drinking water (USDWs) may be endangered. The methods for estimating AoR under the Class VI regulation were developed assuming that GCS reservoirs would be in hydrostatic equilibrium with overlying aquifers. Here we develop and apply an approach to estimating AoR for sites with preinjection relative overpressure for which standard AoR estimation methods produces an infinite AoR. The approach we take is to compare brine leakage through a hypothetical open flowmore » path in the base-case scenario (no-injection) to the incrementally larger leakage that would occur in the CO2-injection case. To estimate AoR by this method, we used semi-analytical solutions to single-phase flow equations to model reservoir pressurization and flow up (single) leaky wells located at progressively greater distances from the injection well. We found that the incrementally larger flow rates for hypothetical leaky wells located 6 km and 4 km from the injection well are ~20% and 30% greater, respectively, than hypothetical baseline leakage rates. If total brine leakage is considered, the results depend strongly on how the incremental increase in total leakage is calculated, varying from a few percent to up to 40% greater (at most at early time) than base-case total leakage.« less

  18. Delineating Area of Review in a System with Pre-injection Relative Overpressure

    SciTech Connect

    Oldenburg, Curtis M.; Cihan, Abdullah; Zhou, Quanlin; Fairweather, Stacey; Spangler, Lee H.

    2014-12-31

    The Class VI permit application for geologic carbon sequestration (GCS) requires delineation of an area of review (AoR), defined as the region surrounding the (GCS) project where underground sources of drinking water (USDWs) may be endangered. The methods for estimating AoR under the Class VI regulation were developed assuming that GCS reservoirs would be in hydrostatic equilibrium with overlying aquifers. Here we develop and apply an approach to estimating AoR for sites with preinjection relative overpressure for which standard AoR estimation methods produces an infinite AoR. The approach we take is to compare brine leakage through a hypothetical open flow path in the base-case scenario (no-injection) to the incrementally larger leakage that would occur in the CO2-injection case. To estimate AoR by this method, we used semi-analytical solutions to single-phase flow equations to model reservoir pressurization and flow up (single) leaky wells located at progressively greater distances from the injection well. We found that the incrementally larger flow rates for hypothetical leaky wells located 6 km and 4 km from the injection well are ~20% and 30% greater, respectively, than hypothetical baseline leakage rates. If total brine leakage is considered, the results depend strongly on how the incremental increase in total leakage is calculated, varying from a few percent to up to 40% greater (at most at early time) than base-case total leakage.

  19. Delineating the Rattlesnake Springs, New Mexico Watershed Using Precision Gravity Techniques

    NASA Astrophysics Data System (ADS)

    Doser, D. I.; Boykov, N. D.; Baker, M. R.; Kaip, G. M.; Langford, R. P.

    2009-12-01

    Rattlesnake Springs serves as the sole domestic water source for Carlsbad Caverns National Park. The recent development of oil and gas leases and agricultural lands surrounding the springs has led to concern about contamination of the fracture controlled aquifer system. We have conducted a series of precision gravity surveys (station spacing 200 to 300 m in a 4 x 4 km area), combined with other geophysical studies and geologic mapping, to delineate possible fracture systems in the gypsum and carbonate bedrock that feed the spring system. Our combined results suggest several pathways for water to enter the springs. A series of WNW-ESE striking features are apparent in our gravity data that appear to align with relict spring valleys we have mapped to the west of the springs. A self potential survey indicates that water is entering the springs at a shallow level from the northwest direction. However, gravity data also indicate a north-south trending fracture system could be providing a pathway for water to enter from the south. This is consistent with drawdown tests conducted in the 1950’s and 1960’s on irrigation wells located to the south of the springs. The north-south fracture system appears related to a basin bounding fault system observed in the regional gravity data.

  20. Evaluation of catchment delineation methods for the medium-resolution National Hydrography Dataset

    USGS Publications Warehouse

    Johnston, Craig M.; Dewald, Thomas G.; Bondelid, Timothy R.; Worstell, Bruce B.; McKay, Lucinda D.; Rea, Alan; Moore, Richard B.; Goodall, Jonathan L.

    2009-01-01

    Different methods for determining catchments (incremental drainage areas) for stream segments of the medium-resolution (1:100,000-scale) National Hydrography Dataset (NHD) were evaluated by the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA). The NHD is a comprehensive set of digital spatial data that contains information about surface-water features (such as lakes, ponds, streams, and rivers) of the United States. The need for NHD catchments was driven primarily by the goal to estimate NHD streamflow and velocity to support water-quality modeling. The application of catchments for this purpose also demonstrates the broader value of NHD catchments for supporting landscape characterization and analysis. Five catchment delineation methods were evaluated. Four of the methods use topographic information for the delineation of the NHD catchments. These methods include the Raster Seeding Method; two variants of a method first used in a USGS New England study-one used the Watershed Boundary Dataset (WBD) and the other did not-termed the 'New England Methods'; and the Outlet Matching Method. For these topographically based methods, the elevation data source was the 30-meter (m) resolution National Elevation Dataset (NED), as this was the highest resolution available for the conterminous United States and Hawaii. The fifth method evaluated, the Thiessen Polygon Method, uses distance to the nearest NHD stream segments to determine catchment boundaries. Catchments were generated using each method for NHD stream segments within six hydrologically and geographically distinct Subbasins to evaluate the applicability of the method across the United States. The five methods were evaluated by comparing the resulting catchments with the boundaries and the computed area measurements available from several verification datasets that were developed independently using manual methods. The results of the evaluation indicated that the two

  1. Classification of building infrastructure and automatic building footprint delineation using airborne laser swath mapping data

    NASA Astrophysics Data System (ADS)

    Caceres, Jhon

    Three-dimensional (3D) models of urban infrastructure comprise critical data for planners working on problems in wireless communications, environmental monitoring, civil engineering, and urban planning, among other tasks. Photogrammetric methods have been the most common approach to date to extract building models. However, Airborne Laser Swath Mapping (ALSM) observations offer a competitive alternative because they overcome some of the ambiguities that arise when trying to extract 3D information from 2D images. Regardless of the source data, the building extraction process requires segmentation and classification of the data and building identification. In this work, approaches for classifying ALSM data, separating building and tree points, and delineating ALSM footprints from the classified data are described. Digital aerial photographs are used in some cases to verify results, but the objective of this work is to develop methods that can work on ALSM data alone. A robust approach for separating tree and building points in ALSM data is presented. The method is based on supervised learning of the classes (tree vs. building) in a high dimensional feature space that yields good class separability. Features used for classification are based on the generation of local mappings, from three-dimensional space to two-dimensional space, known as "spin images" for each ALSM point to be classified. The method discriminates ALSM returns in compact spaces and even where the classes are very close together or overlapping spatially. A modified algorithm of the Hough Transform is used to orient the spin images, and the spin image parameters are specified such that the mutual information between the spin image pixel values and class labels is maximized. This new approach to ALSM classification allows us to fully exploit the 3D point information in the ALSM data while still achieving good class separability, which has been a difficult trade-off in the past. Supported by the spin

  2. Genetic delineation of local provenance defines seed collection zones along a climate gradient

    PubMed Central

    Hufford, Kristina M.; Veneklaas, Erik J.; Lambers, Hans; Krauss, Siegfried L.

    2016-01-01

    Efforts to re-establish native plant species should consider intraspecific variation if we are to restore genetic diversity and evolutionary potential. Data describing spatial genetic structure and the scale of adaptive differentiation are needed for restoration seed sourcing. Genetically defined provenance zones provide species-specific guidelines for the distance within which seed transfer likely maintains levels of genetic diversity and conserves locally adapted traits. While a growing number of studies incorporate genetic marker data in delineation of local provenance, they often fail to distinguish the impacts of neutral and non-neutral variation. We analysed population genetic structure for 134 amplified fragment length polymorphism (AFLP) markers in Stylidium hispidum (Stylidiaceae) along a north–south transect of the species' range with the goal to estimate the distance at which significant genetic differences occur among source and recipient populations in restoration. In addition, we tested AFLP markers for signatures of selection, and examined the relationship of neutral and putatively selected markers with climate variables. Estimates of population genetic structure revealed significant levels of differentiation (ΦPT = 0.23) and suggested a global provenance distance of 45 km for pairwise comparisons of 16 populations. Of the 134 markers, 13 exhibited evidence of diversifying selection (ΦPT = 0.52). Using data for precipitation and thermal gradients, we compared genetic, geographic and environmental distance for subsets of neutral and selected markers. Strong isolation by distance was detected in all cases, but positive correlations with climate variables were present only for markers with signatures of selection. We address findings in light of defining local provenance in ecological restoration. PMID:26755503

  3. Application of remote sensing techniques in land-use planning: Flood-plain delineation. [Cochise County, Arizona

    NASA Technical Reports Server (NTRS)

    Altenstadter, J. (Principal Investigator); Clark, R. B.

    1974-01-01

    The delineation of areas subject to inundation by means of remotely-sensed data acquisition represents a considerable saving in personnel time. Repeated input from aerial sensor sources provides the planner with a potent tool for the formation of a data base and for the monitoring of land use patterns over a period of time. The primary output of this project was a set of base map overlays at a scale of 1:62,500 delineating areas which require special regulations when proposed for land use involving human habitation or certain classes of storage. A secondary product of the study was county-wide maps of watershed configurations and of soil hydrologic groups. Further research is anticipated to extend the mapping of watershed areas outside the political boundaries of Cochise County, which will provide data for subsequent rainfall-runoff relationship studies in the area. All of the data provided will be incorporated into the Cochise County composite computer mapping project now operational. Results of this project have improved the pool of information available to the planning staff of Cochise County.

  4. INVESTIGATION OF HYDROLOEGROLOGIC MAPPING TO DELINEATE PROTECTION ZONES AROUND SPRINGS: REPORT OF TWO CASE STUDIES

    EPA Science Inventory

    Methods commonly used to delineate protection zones for water-supply wells are often not directly applicable for springs. This investigation focuses on characterization of the hydrogeologic setting using hydrogeologic mapping methods to identify geologic and hydrologic features ...

  5. Guidelines for delineation of lymphatic clinical target volumes for high conformal radiotherapy: head and neck region

    PubMed Central

    2011-01-01

    The success of radiotherapy depends on the accurate delineation of the clinical target volume. The delineation of the lymph node regions has most impact, especially for tumors in the head and neck region. The purpose of this article was the development an atlas for the delineation of the clinical target volume for patients, who should receive radiotherapy for a tumor of the head and neck region. Literature was reviewed for localisations of the adjacent lymph node regions and their lymph drain in dependence of the tumor entity. On this basis the lymph node regions were contoured on transversal CT slices. The probability for involvement was reviewed and a recommendation for the delineation of the CTV was generated. PMID:21854585

  6. Hydrologic Modeling and Flood Frequency Analysis for Ordinary High Water Mark Delineation

    DTIC Science & Technology

    2016-02-01

    High Water Mark Delineation Co ld R eg io ns R es ea rc h an d En gi ne er in g La bo ra to ry John D. Gartner, Mathew K. Mersel, and...environmental challenges. ERDC develops innovative solutions in civil and military engineering, geospatial sciences, water resources, and environmental...Program (WRAP) ERDC/CRREL TR-16-2 February 2016 Hydrologic Modeling and Flood Frequency Analysis for Ordinary High Water Mark Delineation John

  7. Delineating Cultural Models: Extending the Cultural Mixture Model

    DTIC Science & Technology

    2011-12-01

    October 2012. Table 1: List of Traits Identified by Different Five-Factor Model of Personality Source Tupes & Christal (1961) Norman...decisions that impact lives. Interestingly, Tupes and Christal (1961) originally included Culture as one of the factors, but this has been subsumed into...Uncertainty in Artificial Intelligence, pp. 504-514. Tupes, E. C., & Christal , R. E. (1961). Recurrent Personality Factors Based on Trait Ratings. USAF

  8. A modular low-complexity ECG delineation algorithm for real-time embedded systems.

    PubMed

    Bote, Jose Manuel; Recas, Joaquin; Rincon, Francisco; Atienza, David; Hermida, Roman

    2017-02-17

    This work presents a new modular and lowcomplexity algorithm for the delineation of the different ECG waves (QRS, P and T peaks, onsets and end). Involving a reduced number of operations per second and having a small memory footprint, this algorithm is intended to perform realtime delineation on resource-constrained embedded systems. The modular design allows the algorithm to automatically adjust the delineation quality in run time to a wide range of modes and sampling rates, from a Ultra-low power mode when no arrhythmia is detected, in which the ECG is sampled at low frequency, to a complete High-accuracy delineation mode in which the ECG is sampled at high frequency and all the ECG fiducial points are detected, in case of arrhythmia. The delineation algorithm has been adjusted using the QT database, providing very high sensitivity and positive predictivity, and validated with the MIT database. The errors in the delineation of all the fiducial points are below the tolerances given by the Common Standards for Electrocardiography (CSE) committee in the High-accuracy mode, except for the P wave onset, for which the algorithm is above the agreed tolerances by only a fraction of the sample duration. The computational load for the ultra-low-power 8-MHz TI MSP430 series microcontroller ranges from 0.2 to 8.5% according to the mode used.

  9. Uncertainty in wellhead protection area delineation due to uncertainty in aquifer parameter values

    NASA Astrophysics Data System (ADS)

    Bhatt, Kailash

    1993-08-01

    The importance of modeling in hydrogeologic investigations has been stressed in a number of studies. Since the applicability of any model is dependent on the type of need and availability of hydrogeological information, a parametric analysis is essential to determine its applicability. This paper presents the results of a parametric analysis conducted to evaluate the effect of data uncertainty on wellhead protection area (WHPA) delineation. The precision of aquifer parameter values is the most important factor in a WHPA delineation process in relation to the model itself. To demonstrate the effect of variable values in a wellfield, we tested modified version of time-related analytical groundwater flow concept using a RESSQC model, which is used for capture zone delineation and to delineate contaminant front for injection wells. The RESSQC model is a modified version of the RESSQ code which was initially designed to only delineate contaminant fronts for injection wells. Field measured aquifer parameters for a shallow aquifer were used in the analysis. The results indicate that great caution must be taken when aquifer parameters such as hydraulic gradient, thickness, transmissivity and porosity are being used for WHPA delineation, since over or under-protection of WHPA can jeopardize the public health. An extended aquifer test and installation of various observation wells in or near different lithologic and depth zones may increase reliability of parameter values.

  10. DEM-based Watershed Delineation - Comparison of Different Methods and applications

    NASA Astrophysics Data System (ADS)

    Chu, X.; Zhang, J.; Tahmasebi Nasab, M.

    2015-12-01

    Digital elevation models (DEMs) are commonly used for large-scale watershed hydrologic and water quality modeling. With aid of the latest LiDAR technology, submeter scale DEM data are often available for many areas in the United States. Precise characterization of the detailed variations in surface microtopography using such high-resolution DEMs is crucial to the related watershed modeling. Various methods have been developed to delineate a watershed, including determination of flow directions and accumulations, identification of subbasin boundaries, and calculation of the relevant topographic parameters. The objective of this study is to examine different DEM-based watershed delineation methods by comparing their unique features and the discrepancies in their results. Not only does this study cover the traditional watershed delineation methods, but also a new puddle-based unit (PBU) delineation method. The specific topics and issues to be presented involve flow directions (D8 single flow direction vs. multi-direction methods), segmentation of stream channels, drainage systems (single "depressionless" drainage network vs. hierarchical depression-dominated drainage system), and hydrologic connectivity (static structural connectivity vs. dynamic functional connectivity). A variety of real topographic surfaces are selected and delineated by using the selected methods. Comparisons of their delineation results emphasize the importance of selection of the methods and highlight their applicability and potential impacts on watershed modeling.

  11. Plastic and Glass Greenhouses Detection and Delineation from WORLDVIEW-2 Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Koc-San, D.; Sonmez, N. K.

    2016-06-01

    Greenhouse detection using remote sensing technologies is an important research area for yield estimation, sustainable development, urban and rural planning and management. An approach was developed in this study for the detection and delineation of greenhouse areas from high resolution satellite imagery. Initially, the candidate greenhouse patches were detected using supervised classification techniques. For this purpose, Maximum Likelihood (ML), Random Forest (RF), and Support Vector Machines (SVM) classification techniques were applied and compared. Then, sieve filter and morphological operations were performed for improving the classification results. Finally, the obtained candidate plastic and glass greenhouse areas were delineated using boundary tracing and Douglas Peucker line simplification algorithms. The proposed approach was implemented in the Kumluca district of Antalya, Turkey utilizing pan-sharpened WorldView-2 satellite imageries. Kumluca is the prominent district of Antalya with greenhouse cultivation and includes both plastic and glass greenhouses intensively. When the greenhouse classification results were analysed, it can be stated that the SVM classification provides most accurate results and RF classification follows this. The SVM classification overall accuracy was obtained as 90.28%. When the greenhouse boundary delineation results were considered, the plastic greenhouses were delineated with 92.11% accuracy, while glass greenhouses were delineated with 80.67% accuracy. The obtained results indicate that, generally plastic and glass greenhouses can be detected and delineated successfully from WorldView-2 satellite imagery.

  12. Using geographic information systems in the delineation of wellhead protection areas

    SciTech Connect

    Shafer, J.M. . Earth Sciences and Resources Inst.); Horton, C.A. . Dept. of Civil Engineering)

    1994-03-01

    The 1986 amendments to the Safe Drinking Water Act established the nationwide wellhead protection program to be administered by the US Environmental Protection Agency. Although individual states have the responsibility to implement wellhead protection, the US EPA provides technical guidance, and approves each wellhead protection plan prepared by the states. A major aspect of wellhead protection strategies is the delineation of wellhead protection areas. These are zones around municipal water supply wells that receive special land use considerations intended to minimize the threat of contamination of the wells. The US EPA has recommended several technical approaches to delineating wellhead protection areas, ranging in sophistication from simple concentric circles around wells to irregular areas determined from groundwater flow and transport analyses. Regardless of the wellhead protection area delineation technique, the resulting area surrounding the municipal well must be accurately mapped. A geographic information system (GIS) approach to mapping the results of wellhead protection area delineation is demonstrated. Using hypothetical groundwater flow regimes, each EPA recommended approach to wellhead protection area delineation is presented in a GIS format. A visual comparison of delineation techniques in terms of area and configuration of the resulting wellhead protection areas is made. Finally, the advantages of using a GIS for representing wellhead protection areas is provided.

  13. CONTRIBUTION OF NUTRIENTS AND E.COLI TO SURFACE WATER CONDITION IN THE OZARKS: PART II USING LANDSCAPE ECOLOGY AND PARTIAL LEAST SQUARES PREDICTIONS TO MAP WATERSHEDS THAT ARE VULNERABLE TO NON-POINT SOURCE POLLUTION

    EPA Science Inventory

    The results of this project provide watershed managers with the first broad-scale predictions that can be used to explain how land cover type, land cover configuration, environmental change, and human activities may affect the chemical and biological characteristics of surface wa...

  14. An integrated SOM-based multivariate approach for spatio-temporal patterns identification and source apportionment of pollution in complex river network.

    PubMed

    Yang, Yonghui; Wang, Cuiyu; Guo, Huaicheng; Sheng, Hu; Zhou, Feng

    2012-09-01

    In this study, three classification techniques (self-organizing maps, hierarchical cluster analysis and discriminant analysis) were applied to identify spatial water pollution levels, temporal water quality response delay phenomena (WQRDP), source pollution types (point, urban non-point, or agricultural non-point). Two models (principal components analysis (PCA), and positive matrix factorization (PMF)) were used to do the further quantitative source apportionment studying. The 27 inflow rivers in spatial were divided into three pollution levels (A, high; B, medium; C, low). The primary pollution pattern in spatial Clusters A, B, and C were point, urban non-point and agricultural non-point separately, in consideration of simultaneous land use types. Source apportionment results identified five typical factors in spatial Cluster A and six typical factors in spatial Cluster B and C as responsible for the data structure, explaining 80%-90% of the total variance of the dataset.

  15. Delineating a shallow fault zone and dipping bed rock strata using multichannal analysis of surface waves with a land streamer

    USGS Publications Warehouse

    Ivanov, J.; Miller, R.D.; Lacombe, P.; Johnson, C.D.; Lane, J.W.

    2006-01-01

    The multichannel analysis of surface waves (MASW) seismic method was used to delineate a fault zone and gently dipping sedimentary bedrock at a site overlain by several meters of regolith. Seismic data were collected rapidly and inexpensively using a towed 30-channel land streamer and a rubberband-accelerated weight-drop seismic source. Data processed using the MASW method imaged the subsurface to a depth of about 20 m and allowed detection of the overburden, gross bedding features, and fault zone. The fault zone was characterized by a lower shear-wave velocity (Vs) than the competent bedrock, consistent with a large-scale fault, secondary fractures, and in-situ weathering. The MASW 2D Vs section was further interpreted to identify dipping beds consistent with local geologic mapping. Mapping of shallow-fault zones and dipping sedimentary rock substantially extends the applications of the MASW method. ?? 2006 Society of Exploration Geophysicists.

  16. Evaluation of methods for delineating areas that contribute water to wells completed in valley-fill aquifers in Pennsylvania

    USGS Publications Warehouse

    Risser, Dennis W.; Madden, Thomas M.

    1994-01-01

    Valley-fill aquifers in Pennsylvania are the source of drinking water for many wells in the glaciated parts of the State and along major river valleys. These aquifers area subject to contamination because of their shallow water-table depth and highly transmissive sediments. The possibility for contamination of water-supply wells in valley-fill aquifers can be minimized by excluding activities that could contaminate areas that contribute water to supply wells. An area that contributes water to a well is identified in this report as either an area of diversion, time-of-travel area, or contributing area. The area of diversion is a projection to land surface of the valley-fill aquifer volume through which water is diverted to a well and the time-of travel area is that fraction of the area of diversion through which water moves to the well in a specified time. The contributing area, the largest of three areas, includes the area of diversion but also incorporates bedrock uplands and other area that contribute water. Methods for delineating areas of diversion and contributing areas in valley-fill aquifers, described and compared in order of increasing complexity, include fixed radius, uniform flow, analytical, semianalytical, and numerical modeling. Delineated areas are considered approximations because the hydraulic properties and boundary conditions of the real ground-water system are simplified even in the most complex numerical methods. Successful application of any of these methods depends on the investigator's understanding of the hydrologic system in and near the well field, and the limitations of the method. The hydrologic system includes not only the valley-fill aquifer but also the regional surface-water and ground-water flow systems within which the valley is situated. As shown by numerical flow simulations of a well field in the valley-fill aquifer along Marsh Creek Valley near Asaph, Pa., water from upland bedrock sources can provide nearly all the water

  17. Delineation of ground-water contamination using soil-gas analyses near Jackson, Tennessee

    USGS Publications Warehouse

    Lee, R.W.

    1991-01-01

    An investigation of the ground-water resources near Jackson, West Tennessee, was conducted during 1988-89. The study included determination of the occurrence of contaminants in the shallow aquifer using soil-gas analyses in the unsaturated zone. Between 1980 and 1988, an underground fuel-storage tank leaked about 3,000 gallons of unleaded fuel to the water table about 4 feet below land surface. A survey of soil gas using a gas chromatograph equipped with a photoionization detector showed concentrations of volatile organic compounds greater than IO, 000 parts per million near the leak These compounds were detected in an area about 240 feet long and 110 feet wide extending west from the point source. The chromatograms provided two distinct 'fingerprints' of volatile organic compounds. The first revealed the presence of benzene, toluene, andxylenes, which are constituents of unleaded fuel, in addition to other volatile compounds, in soil gas in the area near the leak The second did not reveal any detectable benzene, toluene, or xylenes in the soil-gas samples, but showed the presence of other unidentified volatile organic compounds in soil gas north of the storage tank. The distribution of total concentrations of volatile organic compounds in the unsaturated zone indicated that a second plume about 200 feet long and 90 feet wide was present about 100 feet north of the storage tank The second plume could have been the result of previous activities at this site during the 1950's or earlier. Activities at the site are believed to have included storage of solvents used at the nearby railyard and flushing of tanks containing tar onto a gravel-covered parking area. The delineation of these plumes has shown that soil-gas analyses can be a useful technique for identifying areas of contamination with volatile organic compounds in shallow water-table aquifers and may have broad applications in similar situations where the water table is relatively close to the surface.

  18. Utilising Physical, Chemical, And Stable Isotope Techniques To Delineate The Flows Within A Coastal Wetlands System

    NASA Astrophysics Data System (ADS)

    Marimuthu, S.; Reynolds, D. A.

    2004-12-01

    The coastal wetlands system under study comprises a series of small lakes and is very unique in the sense that the lakes within the system display different hydrochemistry and stable isotopic composition although they are connected by channels and form as a cluster of inter-connected lakes. The complex flow systems and the transient nature of the interactions between surface water and groundwater present in the wetlands system were delineated using both chemical and stable isotope data to supplement existing classical hydraulic data. The spatial and temporal variations of chemical and isotopic composition of the individual water bodies within the system were measured for an annual cycle, to provide a unique data set for the analysis. A purely hydraulic analysis of the region surrounding the wetlands would indicate that the wetlands are flow-through bodies, however the chemical and isotope information indicates the lakes almost invariably act as discharge points for the surface water flows and the north south regional groundwater flow. Large volumes of groundwater flow were found within an observed northeast-southwest trending paleochannel within the wetlands system, and in this case, the chemical and isotopic evidence are complimentary with the hydraulic study. The isotope and chloride results from the surface water bodies allowed for the accurate determination of the composition of the major creeks in the system, and a simple portioning model indicated that groundwater is the predominant source for the inflowing creeks. Similarly, the deuterium versus Oxygen-18 and deuterium versus chloride relationships observed in the system portray two distinct evaporation trends, one through the hypersaline lakes and the other through less saline lakes which indicates that the isotopic composition of the water bodies are affected to a great extent by high dissolved salts content. The superposition of these data sets provided a unique vision of the flow system and clearly shows

  19. FECAL BACTERIA SOURCE TRACKING AND BACTEROIDES SPP. HOST SPECIES SPECIFICITY ANALYSIS

    EPA Science Inventory

    Point and non-point pollution sources of fecal pollution on a watershed adversely impact the quality of drinking source waters and recreational waters. States are required to develop total maximum daily loads (TMDLs) and devise best management practices (BMPs) to reduce the po...

  20. Automated individual tree crown delineation from LIDAR data using morphological techniques

    NASA Astrophysics Data System (ADS)

    Jing, L.; Hu, B.; Li, H.; Li, J.; Noland, T.

    2014-03-01

    In current tree crown delineation from LiDAR data, treetops and 3D geometric shapes of tree crowns are frequently extracted from LiDAR-derived Crown Height Model (CHM) and used as references to localize and delineate crowns. However, it is difficult to detect deciduous treetops and delineate deciduous tree crowns. The 3D shape of a crown, which can be derived from CHM, may be taken as a half ellipsoid, and any horizontal slice of the ellipsoid contains the treetop and indicates not only the location but also the spatial extent of the crown. Based on such slices, a novel multi-scale method for individual tree crown delineation from CHM was proposed in this study. This method consists mainly of two steps: (1) morphologically open the CHM over the scale range of target tree crowns; and (2) take local maxima within each resulting opened CHM as the horizontal slices of target crowns at the corresponding scale level and integrate all the slices within the scale range together to represent the spatial distribution of target crowns. In an experiment on CHMs over two natural closed canopy forests in Ontario, Canada, the proposed method accurately delineated the majority of the tree crowns from closed canopy forests.

  1. Multitracer: a Java-based tool for anatomic delineation of grayscale volumetric images.

    PubMed

    Woods, Roger P

    2003-08-01

    A Java-based tool for delineating anatomic boundaries in 8- and 16- bit grayscale volumetric images is described. Modern features implemented by the tool include the ability to simultaneously view the current cursor position and the previously delineated boundaries on three orthogonal planes, the ability to magnify images during delineation using high-quality interpolation, the ability to encode and save boundaries with subvoxel resolution, and the ability to utilize coregistered images interchangeably during delineation. Additional features facilitate use of the tool in a multiuser, multiplatform environment and provide support for the documentation of anatomic delineation protocols. In addition to providing direct estimates of structure volumes, areas, and lengths, the tool allows contoured boundaries to be exported for more sophisticated analyses. The tool also provides support for manual editing of image volumes to remove confounding structures and for manual correction of image volumes that have been inaccurately edited. In addition to its research utility, the tool also has potential value in education, allowing students to interact with volumetric data and structural boundaries in three dimensions.

  2. pyLIDEM: A Python-Based Tool to Delineate Coastal Watersheds Using LIDAR Data

    NASA Astrophysics Data System (ADS)

    O'Banion, R.; Alameddine, I.; Gronewold, A.; Reckhow, K.

    2008-12-01

    Accurately identifying the boundary of a watershed is one of the most fundamental and important steps in any hydrological assessment. Representative applications include defining a study area, predicting overland flow, estimating groundwater infiltration, modeling pollutant accumulation and wash-off rates, and evaluating effectiveness of pollutant mitigation measures. The United States Environmental Protection Agency (USEPA) Total Maximum Daily Load (TMDL) program, the most comprehensive water quality management program in the United States (US), is just one example of an application in which accurate and efficient watershed delineation tools play a critical role. For example, many impaired water bodies currently being addressed through the TMDL program drain small coastal watersheds with relatively flat terrain, making watershed delineation particularly challenging. Most of these TMDL studies use 30-meter digital elevation models (DEMs) that rarely capture all of the small elevation changes in coastal watersheds, leading to errors not only in watershed boundary delineation, but in subsequent model predictions (such as watershed runoff flow and pollutant deposition rate predictions) for which watershed attributes are key inputs. Manually delineating these low-relief coastal watersheds through the use of expert knowledge of local water flow patterns, often produces relatively accurate (and often more accurate) watershed boundaries as compared to the boundaries generated by the 30-meter DEMs. Yet, manual delineation is a costly and time consuming procedure that is often not opted for. There is a growing need, therefore, particularly to address the ongoing needs of the TMDL program (and similar environmental management programs), for software tools which can utilize high resolution topography data to more accurately delineate coastal watersheds. Here, we address this need by developing pyLIDEM (python LIdar DEM), a python-based tool which processes bare earth high

  3. Geographic object-based delineation of neighborhoods of Accra, Ghana using QuickBird satellite imagery.

    PubMed

    Stow, Douglas A; Lippitt, Christopher D; Weeks, John R

    2010-08-01

    The objective was to test GEographic Object-based Image Analysis (GEOBIA) techniques for delineating neighborhoods of Accra, Ghana using QuickBird multispectral imagery. Two approaches to aggregating census enumeration areas (EAs) based on image-derived measures of vegetation objects were tested: (1) merging adjacent EAs according to vegetation measures and (2) image segmentation. Both approaches exploit readily available functions within commercial GEOBIA software. Image-derived neighborhood maps were compared to a reference map derived by spatial clustering of slum index values (from census data), to provide a relative assessment of potential map utility. A size-constrained iterative segmentation approach to aggregation was more successful than standard image segmentation or feature merge techniques. The segmentation approaches account for size and shape characteristics, enabling more realistic neighborhood boundaries to be delineated. The percentage of vegetation patches within each EA yielded more realistic delineation of potential neighborhoods than mean vegetation patch size per EA.

  4. Applicability of VI in arid vegetation delineation using shadow-affected SPOT imagery.

    PubMed

    Gunasekara, N K; Al-Wardy, M M; Al-Rawas, G A; Charabi, Y

    2015-07-01

    GDVI(3), GDVI(2), NDVI, MSAVI and SAVI were evaluated for their dynamic ranges, the class accuracy of the Vegetation Index (VI) classifications, the effects of shadow delineation on the other land use classes and their applicability in vegetation delineation in Al-Qara Mountains, Oman. Supervised classifications of a SPOT scene by Support Vector Machines (SVM) algorithm were employed. GDVI(3) showed the widest dynamic range in all land use types, while GDVI(2) also exhibited evidently wider dynamic ranges for arid to semi-arid Al-Qara than NDVI, MSAVI and SAVI. GDVI(3) reported the highest accuracies in delineating natural vegetation (dense - 74.80%, medium-dense- 43.19%), except for low-dense vegetation (40.51%). It also performs the best in delineating bare soil and dry grass with over 80% and 60% accuracies. The attenuated reflectance created by the shadows results in VI signals in the range of dry grass to bare soil, enabling us to neglect the shadow effect on natural vegetation delineation due to below 9.50% omissions from the shadows class. GDVI(3) also limits shadow delineation better than the other indices, which will enable us to analyze spectral information recovery by the VI with the help of ground truth information under the shadows. For applications such as land degradation assessments, GDVI(3) has better prospects over the other indices explored. Saturation at high-vigor vegetation is an issue in GDVI(3), GDVI(2) and NDVI. Our study also points to a dependency of a VI's capability to weaken shadows on the number of training data pixels to be utilized in a supervised classification.

  5. Breast ultrasound lesions classification: a performance evaluation between manual delineation and computer segmentation

    NASA Astrophysics Data System (ADS)

    Yap, Moi Hoon; Yap, Chuin Hong

    2016-03-01

    Breast cancer is a threat to women worldwide. Manual delineation on breast ultrasound lesions is time-consuming and operator dependent. Computer segmentation of ultrasound breast lesions can be a challenging task due to the ill-defined lesions boundaries and issues related to the speckle noise in ultrasound images. The main contribution of this paper is to compare the performance of the computer classifier on the manual delineation and computer segmentation in malignant and benign lesions classification. This paper we implement computer segmentation using multifractal approach on a database consists of 120 images (50 malignant lesions and 70 benign lesions). The computer segmentation result is compared with the manual delineation using Jaccard Similarity Index (JSI). The result shows that the average JSI of 0.5010 (+/-0.2088) for malignant lesions and the average JSI of 0.6787 (+/-0.1290) for benign lesions. These results indicate lower agreement in malignant lesions due to the irregular shape while the higher agreement in benign lesions with regular shape. Further, we extract the shape descriptors for the lesions. By using logistic regression with 10 fold cross validation, the classification rates of manual delineation and computer segmentation are computed. The computer segmentation produced results with sensitivity 0.780 and specificity 0.871. However, the manual delineation produced sensitivity of 0.520 and specificity of 0.800. The results show that there are no clear differences between the delineation in MD and CS in benign lesions but the computer segmentation on malignant lesions shows better accuracy for computer classifier.

  6. Delineating baseflow contribution areas for streams - A model and methods comparison.

    PubMed

    Chow, Reynold; Frind, Michael E; Frind, Emil O; Jones, Jon P; Sousa, Marcelo R; Rudolph, David L; Molson, John W; Nowak, Wolfgang

    2016-12-01

    This study addresses the delineation of areas that contribute baseflow to a stream reach, also known as stream capture zones. Such areas can be delineated using standard well capture zone delineation methods, with three important differences: (1) natural gradients are smaller compared to those produced by supply wells and are therefore subject to greater numerical errors, (2) stream discharge varies seasonally, and (3) stream discharge varies spatially. This study focuses on model-related uncertainties due to model characteristics, discretization schemes, delineation methods, and particle tracking algorithms. The methodology is applied to the Alder Creek watershed in southwestern Ontario. Four different model codes are compared: HydroGeoSphere, WATFLOW, MODFLOW, and FEFLOW. In addition, two delineation methods are compared: reverse particle tracking and reverse transport, where the latter considers local-scale parameter uncertainty by using a macrodispersion term to produce a capture probability plume. The results from this study indicate that different models can calibrate acceptably well to the same data and produce very similar distributions of hydraulic head, but can produce different capture zones. The stream capture zone is found to be highly sensitive to the particle tracking algorithm. It was also found that particle tracking by itself, if applied to complex systems such as the Alder Creek watershed, would require considerable subjective judgement in the delineation of stream capture zones. Reverse transport is an alternative and more reliable approach that provides probability intervals for the baseflow contribution areas, taking uncertainty into account. The two approaches can be used together to enhance the confidence in the final outcome.

  7. Delineating baseflow contribution areas for streams - A model and methods comparison

    NASA Astrophysics Data System (ADS)

    Chow, Reynold; Frind, Michael E.; Frind, Emil O.; Jones, Jon P.; Sousa, Marcelo R.; Rudolph, David L.; Molson, John W.; Nowak, Wolfgang

    2016-12-01

    This study addresses the delineation of areas that contribute baseflow to a stream reach, also known as stream capture zones. Such areas can be delineated using standard well capture zone delineation methods, with three important differences: (1) natural gradients are smaller compared to those produced by supply wells and are therefore subject to greater numerical errors, (2) stream discharge varies seasonally, and (3) stream discharge varies spatially. This study focuses on model-related uncertainties due to model characteristics, discretization schemes, delineation methods, and particle tracking algorithms. The methodology is applied to the Alder Creek watershed in southwestern Ontario. Four different model codes are compared: HydroGeoSphere, WATFLOW, MODFLOW, and FEFLOW. In addition, two delineation methods are compared: reverse particle tracking and reverse transport, where the latter considers local-scale parameter uncertainty by using a macrodispersion term to produce a capture probability plume. The results from this study indicate that different models can calibrate acceptably well to the same data and produce very similar distributions of hydraulic head, but can produce different capture zones. The stream capture zone is found to be highly sensitive to the particle tracking algorithm. It was also found that particle tracking by itself, if applied to complex systems such as the Alder Creek watershed, would require considerable subjective judgement in the delineation of stream capture zones. Reverse transport is an alternative and more reliable approach that provides probability intervals for the baseflow contribution areas, taking uncertainty into account. The two approaches can be used together to enhance the confidence in the final outcome.

  8. Unsupervised boundary delineation of spinal neural foramina using a multi-feature and adaptive spectral segmentation.

    PubMed

    He, Xiaoxu; Zhang, Heye; Landis, Mark; Sharma, Manas; Warrington, James; Li, Shuo

    2017-02-01

    As a common disease in the elderly, neural foramina stenosis (NFS) brings a significantly negative impact on the quality of life due to its symptoms including pain, disability, fall risk and depression. Accurate boundary delineation is essential to the clinical diagnosis and treatment of NFS. However, existing clinical routine is extremely tedious and inefficient due to the requirement of physicians' intensively manual delineation. Automated delineation is highly needed but faces big challenges from the complexity and variability in neural foramina images. In this paper, we propose a pure image-driven unsupervised boundary delineation framework for the automated neural foramina boundary delineation. This framework is based on a novel multi-feature and adaptive spectral segmentation (MFASS) algorithm. MFASS firstly utilizes the combination of region and edge features to generate reliable spectral features with a good separation between neural foramina and its surroundings, then estimates an optimal separation threshold for each individual image to separate neural foramina from its surroundings. This self-adjusted optimal separation threshold, estimated from spectral features, successfully overcome the diverse appearance and shape variations. With the robustness from the multi-feature fusion and the flexibility from the adaptively optimal separation threshold estimation, the proposed framework, based on MFASS, provides an automated and accurate boundary delineation. Validation was performed in 280 neural foramina MR images from 56 clinical subjects. Our method was benchmarked with manual boundary obtained by experienced physicians. Results demonstrate that the proposed method enjoys a high and stable consistency with experienced physicians (Dice: 90.58% ± 2.79%; SMAD: 0.5657 ± 0.1544 mm). Therefore, the proposed framework enables an efficient and accurate clinical tool in the diagnosis of neural foramina stenosis.

  9. The use of remote sensing and natural indicators to delineate floodplains - Preliminary findings

    NASA Technical Reports Server (NTRS)

    Sollers, S. C.; Petersen, G. W.; Henninger, D. L.; Borden, F. Y.

    1974-01-01

    Feasibility studies to delineate floodplains using aerial photography have been conducted by the Army Corps of Engineers. The objective of this project is to establish floodplain boundaries using natural indicators such as vegetation types, soil types, moisture differences, and geologic variations. Using aircraft multispectral data, an automated mapping routine should enable the Corps of Engineers to reduce costly field surveys and improve the accuracy of floodplain delineation in pristine areas. The purpose of this paper is to document the methodology utilized in this investigation while using one of a series of available data sets and test sites and to report preliminary findings.

  10. The Benefits and Limitations of Hydraulic Modeling for Ordinary High Water Mark Delineation

    DTIC Science & Technology

    2016-02-01

    High Water Mark Delineation Co ld R eg io ns R es ea rc h an d En gi ne er in g La bo ra to ry John D. Gartner, Matthew K. Mersel...sciences, water resources, and environmental sciences for the Army, the Department of Defense, civilian agencies, and our nation’s public good. Find out...for Ordinary High Water Mark Delineation John D. Gartner, Matthew K. Mersel, Lindsey E. Lefebvre, and Robert W. Lichvar U.S. Army Engineer Research

  11. Detailed Vertical and Lateral Delineation of Redox Zones in Contaminant Plumes Using Redox-Sensitive Tapes (RST)

    NASA Astrophysics Data System (ADS)

    Blum, P.; Oeste, F. D.; Melzer, R.; Martus, P.

    2006-12-01

    Innovative redox-sensitive tapes (RST) have been developed for a detailed vertical and lateral delineation of redox zones in contaminated aquifers. The RST have the potential to become an integral part of a data acquisition strategy for monitored natural attenuation (MNA). The tape material, consists of a 2 cm wide synthetic textile coated with reactive manganese dioxide minerals. The RST are submerged into existing monitoring wells for approximately one month. This time period is sufficient to allow for a reaction of the mineral coating with groundwater. The RST are aimed at investigating four different redox-zones in contaminated aquifers: Mn(II)-oxidizing, Mn(IV)-reducing, Fe(III)-reducing and sulfate-reducing. Two RST case studies are presented. The RST investigations on a coal tar contaminated site allowed for a precise lateral and vertical delineation of the contaminant plume using the existing monitoring well network. The RST investigations on a BTEX contaminated site yielded a good correlation of RST data with hydrochemical data at the wells sampled. In the majority of plume wells located 50 m downstream of the source area and beyond, Mn(IV)-reducing environment appeared to be prevailing. Comparing the RST data with hydrochemical data indicated evidence for the transport of transformation products with groundwater flow. The repeated application of the RST facilitated an assessment of the plume dynamics. No significant seasonal variation with respect to the redox zone distribution was observed within the contaminant plume. However, the assessment of the changes in redox conditions over a time period of 2.5 years showed that the iron-reducing zone is shrinking and the sulfate-reducing zone disappeared completely indicating that the contaminant plume might decrease in the near future. Thus, the application of the RST facilitated an assessment of the plume dynamics on a centimeter-scale without the necessity of pumping and treating contaminated groundwater.

  12. Delineation of a quick clay zone at Smørgrav, Norway, with electromagnetic methods under geotechnical constraints

    NASA Astrophysics Data System (ADS)

    Kalscheuer, Thomas; Bastani, Mehrdad; Donohue, Shane; Persson, Lena; Aspmo Pfaffhuber, Andreas; Reiser, Fabienne; Ren, Zhengyong

    2013-05-01

    In many coastal areas of North America and Scandinavia, post-glacial clay sediments have emerged above sea level due to iso-static uplift. These clays are often destabilised by fresh water leaching and transformed to so-called quick clays as at the investigated area at Smørgrav, Norway. Slight mechanical disturbances of these materials may trigger landslides. Since the leaching increases the electrical resistivity of quick clay as compared to normal marine clay, the application of electromagnetic (EM) methods is of particular interest in the study of quick clay structures. For the first time, single and joint inversions of direct-current resistivity (DCR), radiomagnetotelluric (RMT) and controlled-source audiomagnetotelluric (CSAMT) data were applied to delineate a zone of quick clay. The resulting 2-D models of electrical resistivity correlate excellently with previously published data from a ground conductivity metre and resistivity logs from two resistivity cone penetration tests (RCPT) into marine clay and quick clay. The RCPT log into the central part of the quick clay identifies the electrical resistivity of the quick clay structure to lie between 10 and 80 Ω m. In combination with the 2-D inversion models, it becomes possible to delineate the vertical and horizontal extent of the quick clay zone. As compared to the inversions of single data sets, the joint inversion model exhibits sharper resistivity contrasts and its resistivity values are more characteristic of the expected geology. In our preferred joint inversion model, there is a clear demarcation between dry soil, marine clay, quick clay and bedrock, which consists of alum shale and limestone.

  13. Ictal onset zone and seizure propagation delineated on ictal F-18 fluorodeoxyglucose positron emission tomography/computed tomography.

    PubMed

    Tripathi, Madhavi; Tripathi, Manjari; Garg, Ajay; Damle, Nishikant; Bal, Chandrasekhar

    2016-01-01

    The present case highlights the utility of ictal F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in delineating the seizure onset zone in a child with complex partial seizures. Although F-18 FDG PET has been successfully used to delineate interictal hypometabolism, planned ictal FDG PET, in cases with prolonged seizure activity, can provide better spatial resolution than single-photon emission CT by delineating the seizure onset zone and propagation pathway.

  14. How the Energy and Water Development Appropriations Act of 1993 has impacted the constitutional dynamics of federal wetlands delineation and regulation

    SciTech Connect

    Johnson, J.J.S.; Logan, W.L.

    1995-12-31

    A reliable source of specific criteria for recognizing a wetland, as defined for regulatory purposes would be valuable. In 1987 the Army Corps of Engineers developed a technical manual for identifying wetlands (1987 Wetlands Manual). An interagency manual (1989 Wetlands Manual) was later developed. This manual has been used to identify wetlands according to three evidentiary factors: vegetation, hydrology, and soil. This paper addresses the development of criteria to delineate wetlands, and describes some of the logic used by federal courts to uphold the limited constitutional use of the 1989 Wetlands Manual.

  15. Simulation of ground-water flow and delineation of areas contributing recharge to municipal water-supply wells, Muscatine, Iowa

    USGS Publications Warehouse

    Savoca, Mark E.; Lucey, Keith J.; Lanning, Brian D.

    2002-01-01

    Mississippi River alluvium in the Muscatine, Iowa, area provides large quantities of good quality ground water for municipal, industrial, and agricultural supplies. Three municipal well fields for the City of Muscatine produce a total of about 27 million gallons per day from the alluvium. A previously published steady-state ground-water flow model was modified, and results from the model were used with particle-tracking software to delineate approximate areas contributing recharge to Muscatine Power and Water municipal supply wells and to determine zones of transport within the areas contributing recharge. Under steady-state conditions and 1998 pumpage, primary sources of inflow to the ground-water flow system are recharge through infiltration of precipitation and upland runoff (53 percent) and Mississippi River leakage (41 percent). The primary components of outflow from the ground-water flow system are pumpage (39.6 percent), flow to drainage ditches in Illinois (32.9 percent), and Muscatine Slough leakage (24.7 percent). Several sources of water are present within estimated areas contributing recharge to Muscatine Power and Water municipal well fields including ground water from the alluvial aquifer, Mississippi River water, and recharge originating as runoff from two unnamed creeks in the northern part of the study area. Recharge originating from the Mississippi River accounts for about 46 percent of the total water discharged from the municipal well fields. The average simulated traveltime of particles tracked from recharge to discharge at the municipal well fields was 13.6 years. Particle-tracking results illustrate the influence of nearby industrial supply wells on the shape and size of the area contributing recharge to Muscatine Power and Water wells. Two large embayments into the area contributing recharge to municipal wells are present along the Mississippi River. These areas represent ground water that is unavailable to municipal wells due to withdrawals

  16. Respiration effect on wavelet-based ECG T-wave end delineation strategies.

    PubMed

    Noriega, Maikel; Martínez, Juan Pablo; Laguna, Pablo; Bailón, Raquel; Almeida, Rute

    2012-07-01

    The main purpose of this paper is to study the influence of the mechanical effect of respiration over the T-wave end delineation. We compared the performance of an automatic delineation system based on the wavelet transform (WT), considering single lead (SL), global delineation locations obtained from SL annotations (SLR), and multilead (ML) approaches. The linear relation between the variations on T-wave end locations obtained with each of the methods and the mechanical effect of respiration was quantified using spectral coherence and ARARX modeling both in simulated signals and in real data. We also explored the evolution of the vectorcardiographic spatial loop using the projection on the main direction of the WT in the region close to the T-wave end ( T(e)) and its relation with respiration. The dispersion of the additional T-wave end location error due to respiration was reduced by 15% using SLR with respect to SL, while ML allows for a reduction of around 40%. The percentage of that error correlated with respiration was in average 99% using SL while 82% and 72% using SLR and ML, respectively. Thus, results suggest that ML is the most adequate strategy for T-wave delineation, allowing the reduction of the instability of T-wave end location caused by respiration.

  17. Using the Gravity Model to Delineate a Trade Area: A Class Project.

    ERIC Educational Resources Information Center

    Dzik, Anthony J.

    1992-01-01

    Reports that students who might be bored or intimidated by economic geographic theory become enthusiastic when they can apply it to their own experiences. Describes a class project involving fieldwork and in-class analysis on delineating the retail trade area of a small Ohio city. Includes three maps and mathematical formulae for data analysis.…

  18. Comparison of three image segmentation techniques for target volume delineation in positron emission tomography.

    PubMed

    Drever, Laura A; Roa, Wilson; McEwan, Alexander; Robinson, Don

    2007-03-09

    Incorporation of positron emission tomography (PET) data into radiotherapy planning is currently under investigation for numerous sites including lung, brain, head and neck, breast, and prostate. Accurate tumor-volume quantification is essential to the proper utilization of the unique information provided by PET. Unfortunately,target delineation within PET currently remains a largely unaddressed problem. We therefore examined the ability of three segmentation methods-thresholding, Sobel edge detection, and the watershed approach-to yield accurate delineation of PET target cross-sections. A phantom study employing well-defined cylindrical and spherical volumes and activity distributions provided an opportunity to assess the relative efficacy with which the three approaches could yield accurate target delineation in PET. Results revealed that threshold segmentation can accurately delineate target cross-sections, but that the Sobel and watershed techniques both consistently fail to correctly identify the size of experimental volumes. The usefulness of threshold-based segmentation is limited, however, by the dependence of the correct threshold (that which returns the correct area at each image slice) on target size.

  19. 365. J.W., Delineator February 1934 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    365. J.W., Delineator February 1934 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SAN FRANCISCO ANCHORAGE; PIER NO. 1 - DETAILS; CONTRACT NO. 3; SUP. DRAWING NO. 22A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  20. 364. J.G.M., Delineator February 1934 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    364. J.G.M., Delineator February 1934 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; CONTRACT NO. 6; SUPERSTRUCTURE - WEST BAY CROSSING; SAN FRANCISCO ANCHORAGE CABLE BENT CASTING; AMERICAN BRIDGE CO.; AMBRIDGE PLANT; ORDER NO. G 4852 C; SHEET NO. 100 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  1. 363. A.C.S., Delineator March 1934 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    363. A.C.S., Delineator March 1934 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; CONTRACT NO. 6A; SUPERSTRUCTURE - WEST BAY CROSSING; SAN FRANCISCO ANCHORAGE; AMERICAN BRIDGE CO.; AMBRIDGE PLANT; ORDER NO. G4866; SHEET NO E3 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  2. 358. E.S.T., Delineator April 1935 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    358. E.S.T., Delineator April 1935 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SAN FRANCISCO SECTION AND APPROACHES; GIRDER AND FLOOR BEAM DETAILS; SPANS 5 TO 32; CONTRACT NO. 15 & 15A; SUP. DRAWING NO. 8A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  3. 392. J.R.L., Delineator August 1933 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    392. J.R.L., Delineator August 1933 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - EAST BAY CROSSING; PIER El; ANCHORAGE STEEL WORK; CONTRACT NO. 7; SUP. DRAWING NO. 72A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  4. 371. A.J.M. and D.L.S., Delineators April 1934. STATE OF CALIFORNIA; ...

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

    371. A.J.M. and D.L.S., Delineators April 1934. STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; PIER NO. 4; VERTICAL SECTIONS; CONTRACT NO. 2; SUP. DRAWING NO. 17A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  5. 357. E.S.T., Delineator April 1935 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    357. E.S.T., Delineator April 1935 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SAN FRANCISCO SECTION AND APPROACHES; GENERAL PLAN AND ELEVATION; CONTRACT NO. 15 AND 15A; SUP. DRAWINGS NO. 1-A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  6. 388. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    388. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; SUSPENDED STRUCTURE; SIDE SPAN TRUSSES AT ANCHORAGES; CONTRACT NO. 6; DRAWING NO. 40 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  7. 376. A.J.M. and D.L.S., Delineators February 1934 STATE OF CALIFORNIA; ...

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

    376. A.J.M. and D.L.S., Delineators February 1934 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; YERBA BUENA CROSSING; CROSS-SECTIONS OF CABLE ANCHORAGE; CONTRACT NO. 5; SUP. DRAWING NO. 4A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  8. 378. A.C.S., Delineator March 1933 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    378. A.C.S., Delineator March 1933 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; CONTRACT NO. 6A; SUPERSTRUCTURE - WEST BAY CROSSING; YERBA BUENA ANCHORAGE & CABLE BENT. AMERICAN BRIDGE CO.; AMBRIDGE PLANT; ORDER NO. G 4866; SHEET NO. E4 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  9. 387. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    387. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; TOWERS 2, 3, 5 & 6; BRACING DETAILS - LOWER DECK; CONTRACT NO. 6; DRAWING NO. 27 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  10. 367. J.W.G., Delineator August 1933 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    367. J.W.G., Delineator August 1933 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; PIER NO. 5; GENERAL PLAN & ELEVATION; CONTRACT NO. 2; SUP. DRAWING NO. 10A - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  11. Multimodality Tumor Delineation and Predictive Modelling via Fuzzy-Fusion Deformable Models and Biological Potential Functions

    NASA Astrophysics Data System (ADS)

    Wasserman, Richard Marc

    The radiation therapy treatment planning (RTTP) process may be subdivided into three planning stages: gross tumor delineation, clinical target delineation, and modality dependent target definition. The research presented will focus on the first two planning tasks. A gross tumor target delineation methodology is proposed which focuses on the integration of MRI, CT, and PET imaging data towards the generation of a mathematically optimal tumor boundary. The solution to this problem is formulated within a framework integrating concepts from the fields of deformable modelling, region growing, fuzzy logic, and data fusion. The resulting fuzzy fusion algorithm can integrate both edge and region information from multiple medical modalities to delineate optimal regions of pathological tissue content. The subclinical boundaries of an infiltrating neoplasm cannot be determined explicitly via traditional imaging methods and are often defined to extend a fixed distance from the gross tumor boundary. In order to improve the clinical target definition process an estimation technique is proposed via which tumor growth may be modelled and subclinical growth predicted. An in vivo, macroscopic primary brain tumor growth model is presented, which may be fit to each patient undergoing treatment, allowing for the prediction of future growth and consequently the ability to estimate subclinical local invasion. Additionally, the patient specific in vivo tumor model will be of significant utility in multiple diagnostic clinical applications.

  12. Delineation of Roles and Functions of Respiratory Therapy Personnel. Final Report.

    ERIC Educational Resources Information Center

    American Association for Respiratory Therapy, Dallas, TX.

    Frequently assigned tasks performed by qualified respiratory therapy personnel are delineated in the document in such a manner that proficiency examinations within the profession can be prepared from them. Four distinct proficiency levels are identified and defined. Due to the fact that proficiency examinations will be assigned for them,…

  13. Instructor Strategic Ambiguity: Delineation of the Construct and Development of a Measure

    ERIC Educational Resources Information Center

    Klyukovski, Andrei A.; Medlock-Klyukovski, Amanda L.

    2016-01-01

    This article presents research to delineate the construct of instructor strategic ambiguity (ISA) and develop a measure. The first study analyzed instructor uses of ambiguity, identified 18 strategies, and classified them into four categories. The second study developed an Instructor Strategic Ambiguity Measure (ISAM) for the college classroom.…

  14. 355. J.R.L., Delineator Date Unknown STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    355. J.R.L., Delineator Date Unknown STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; PRELIMINARY LAYOUT STUDIES; DRG. NO. 3 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  15. 411. Delineator Unknown November 2, 1933 1/8" SCALE DETAIL STUDY ...

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

    411. Delineator Unknown November 2, 1933 1/8" SCALE DETAIL STUDY OF S.F. ANCHORAGE; SAN FRANCISCO OAKLAND BAY BRIDGE; TIMOTHY L. PFLUEGER, ARTHUR BROWN JR., JOHN J. DONOVAN; BOARD OF CONSULTING ARCHITECTS; SHEET NO. R31 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  16. 75 FR 39052 - 2010 Standards for Delineating Metropolitan and Micropolitan Statistical Areas

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... BUDGET 2010 Standards for Delineating Metropolitan and Micropolitan Statistical Areas Correction In... Statistical Areas and New England City and Town Areas, in the last line of paragraph (a), ``75'' should read... column, in paragraph (f), in the first and second lines, ``Metropolitan and Metropolitan Statistical...

  17. Electrochemical method for defect delineation in silicon-on-insulator wafers

    DOEpatents

    Guilinger, Terry R.; Jones, Howland D. T.; Kelly, Michael J.; Medernach, John W.; Stevenson, Joel O.; Tsao, Sylvia S.

    1991-01-01

    An electrochemical method for defect delineation in thin-film SOI or SOS wafers in which a surface of a silicon wafer is electrically connected so as to control the voltage of the surface within a specified range, the silicon wafer is then contacted with an electrolyte, and, after removing the electrolyte, defects and metal contamination in the silicon wafer are identified.

  18. An automatic, stagnation point based algorithm for the delineation of Wellhead Protection Areas

    NASA Astrophysics Data System (ADS)

    Tosco, Tiziana; Sethi, Rajandrea; di Molfetta, Antonio

    2008-07-01

    Time-related capture areas are usually delineated using the backward particle tracking method, releasing circles of equally spaced particles around each well. In this way, an accurate delineation often requires both a very high number of particles and a manual capture zone encirclement. The aim of this work was to propose an Automatic Protection Area (APA) delineation algorithm, which can be coupled with any model of flow and particle tracking. The computational time is here reduced, thanks to the use of a limited number of nonequally spaced particles. The particle starting positions are determined coupling forward particle tracking from the stagnation point, and backward particle tracking from the pumping well. The pathlines are postprocessed for a completely automatic delineation of closed perimeters of time-related capture zones. The APA algorithm was tested for a two-dimensional geometry, in homogeneous and nonhomogeneous aquifers, steady state flow conditions, single and multiple wells. Results show that the APA algorithm is robust and able to automatically and accurately reconstruct protection areas with a very small number of particles, also in complex scenarios.

  19. Role Delineation for the Position of Director of Worksite Health Promotion Programs.

    ERIC Educational Resources Information Center

    Golaszewski, Thomas; And Others

    1994-01-01

    A six-step process defines and validates the role of worksite health promotion directors: developing expert opinion consensus, examining current job descriptions, reviewing literature, reviewing independent role delineations, developing competency statements, and validating statements to reduce the number to 80. The competencies are categorized as…

  20. INVESTIGATION OF HYDROGEOLOGIC MAPPING TO DELINEATE PROTECTION ZONES AROUND SPRINGS: REPORT OF TWO CASE STUDIES

    EPA Science Inventory

    Methods commonly used to delineate protection zones for water-supply wells are often not directly applicable for springs. This investigation focuses on the use of hydrogeologic mapping methods to identify physical and hydrologic features that control ground-water flow to springs...

  1. What Community College Students Value: Delineating a Normative Structure for Community College Students

    ERIC Educational Resources Information Center

    Akin, Renea; Park, Toby J.

    2016-01-01

    This manuscript delineates a normative structure for community college students, outlines how this structure varies by student characteristics, and compares this structure to that of a previously established normative structure identified at a 4-year institution. A total of 512 student survey responses on the College Student Behaviors Inventory…

  2. Automatic delineation of tumor volumes by co-segmentation of combined PET/MR data

    NASA Astrophysics Data System (ADS)

    Leibfarth, S.; Eckert, F.; Welz, S.; Siegel, C.; Schmidt, H.; Schwenzer, N.; Zips, D.; Thorwarth, D.

    2015-07-01

    Combined PET/MRI may be highly beneficial for radiotherapy treatment planning in terms of tumor delineation and characterization. To standardize tumor volume delineation, an automatic algorithm for the co-segmentation of head and neck (HN) tumors based on PET/MR data was developed. Ten HN patient datasets acquired in a combined PET/MR system were available for this study. The proposed algorithm uses both the anatomical T2-weighted MR and FDG-PET data. For both imaging modalities tumor probability maps were derived, assigning each voxel a probability of being cancerous based on its signal intensity. A combination of these maps was subsequently segmented using a threshold level set algorithm. To validate the method, tumor delineations from three radiation oncologists were available. Inter-observer variabilities and variabilities between the algorithm and each observer were quantified by means of the Dice similarity index and a distance measure. Inter-observer variabilities and variabilities between observers and algorithm were found to be comparable, suggesting that the proposed algorithm is adequate for PET/MR co-segmentation. Moreover, taking into account combined PET/MR data resulted in more consistent tumor delineations compared to MR information only.

  3. Resource Documentation and Recharge Area Delineation of a Large Fluvial Karst System: Carroll Cave, Missouri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Located along Wet Glaize Creek in the central Missouri Ozarks, Toronto Spring is a distributary spring system where surface stream flow mixes with flow from the Carroll Cave system. Following recharge area delineations for Thunder River and Confusion Creek in Carroll Cave, flow from these rivers wa...

  4. Differential assessment of designations of wetland status using two delineation methods.

    PubMed

    Wu, Meiyin; Kalma, Dennis; Treadwell-Steitz, Carol

    2014-07-01

    Two different methods are commonly used to delineate and characterize wetlands. The U.S. Army Corps of Engineers (ACOE) delineation method uses field observation of hydrology, soils, and vegetation. The U.S. Fish and Wildlife Service's National Wetland Inventory Program (NWI) relies on remote sensing and photointerpretation. This study compared designations of wetland status at selected study sites using both methods. Twenty wetlands from the Wetland Boundaries Map of the Ausable-Boquet River Basin (created using the revised NWI method) in the Ausable River watershed in Essex and Clinton Counties, NY, were selected for this study. Sampling sites within and beyond the NWI wetland boundaries were selected. During the summers of 2008 and 2009, wetland hydrology, soils, and vegetation were examined for wetland indicators following the methods described in the ACOE delineation manual. The study shows that the two methods agree at 78 % of the sampling sites and disagree at 22 % of the sites. Ninety percent of the sampling locations within the wetland boundaries on the NWI maps were categorized as ACOE wetlands with all three ACOE wetland indicators present. A binary linear logistic regression model analyzed the relationship between the designations of the two methods. The outcome of the model indicates that 83 % of the time, the two wetland designation methods agree. When discrepancies are found, it is the presence or absence of wetland hydrology and vegetation that causes the differences in delineation.

  5. Clinical target volume delineation including elective nodal irradiation in preoperative and definitive radiotherapy of pancreatic cancer

    PubMed Central

    2012-01-01

    Background Radiotherapy (RT) is widely used in the treatment of pancreatic cancer. Currently, recommendation has been given for the delineation of the clinical target volume (CTV) in adjuvant RT. Based on recently reviewed pathologic data, the aim of this study is to propose criteria for the CTV definition and delineation including elective nodal irradiation (ENI) in the preoperative and definitive treatment of pancreatic cancer. Methods The anatomical structures of interest, as well as the abdominal vasculature were identified on intravenous contrast-enhanced CT scans of two different patients with pancreatic cancer of the head and the body. To delineate the lymph node area, a margin of 10 mm was added to the arteries. Results We proposed a set of guidelines for elective treatment of high-risk nodal areas and CTV delineation. Reference CT images were provided. Conclusions The proposed guidelines could be used for preoperative or definitive RT for carcinoma of the head and body of the pancreas. Further clinical investigations are needed to validate the defined CTVs. PMID:22691275

  6. Integrating Ensemble Data Assimilation and Indicator Geostatistics to Delineate Hydrofacies Spatial Distribution

    NASA Astrophysics Data System (ADS)

    Song, X.; Chen, X.; Ye, M.; Dai, Z.; Hammond, G. E.

    2015-12-01

    We present a new framework for delineating spatial distributions of hydrofacies from indirect data by linking ensemble-based data assimilation method (e.g., Ensemble Kalman filter, EnKF) with indicator geostatistics based on transition probability. The nature of ensemble data assimilation makes the framework efficient and flexible to integrate various types of observation data. We leveraged the level set concept to establish transformations between discrete hydrofacies and continuous variables, which is a critical element to implement ensemble data assimilation methods for hydrofacies delineation. T-PROGS is used to generate realizations of hydrofacies fields given conditioning points. An additional quenching step of T-PROGS is taken to preserve spatial structure of updated hydrofacies after each data assimilation step. This new method is illustrated by a two-dimensional (2-D) synthetic study in which transient hydraulic head data resulting from pumping is assimilated to delineate hydrofacies distribution. Our results showed that the proposed framework was able to characterize hydrofacies distribution and their associated permeability with adequate accuracy even with limited direct hydrofacies data. This method may find broader applications in facies delineation using other types of indirect measurements, such as tracer tests and geophysical surveys.

  7. Models of Racial and Ethnic Identity Development: Delineation of Practice Implications.

    ERIC Educational Resources Information Center

    Kwan, Kwong-Liem Karl

    2001-01-01

    Summarizes common themes that emerged from the articles in this special issue of "Journal of Mental Health Counseling" on the counseling of racially diverse clients. Discusses variables that need to be addressed when working with members of visible racial and ethnic groups, and delineates some assessment questions for counselors.…

  8. The utility of petroleum seismic exploration data in delineating structural features within salt anticlines

    USGS Publications Warehouse

    Stockton, S.L.; Balch, Alfred H.

    1978-01-01

    The Salt Valley anticline, in the Paradox Basin of southeastern Utah, is under investigation for use as a location for storage of solid nuclear waste. Delineation of thin, nonsalt interbeds within the upper reaches of the salt body is extremely important because the nature and character of any such fluid- or gas-saturated horizons would be critical to the mode of emplacement of wastes into the structure. Analysis of 50 km of conventional seismic-reflection data, in the vicinity of the anticline, indicates that mapping of thin beds at shallow depths may well be possible using a specially designed adaptation of state-of-the-art seismic oil-exploration procedures. Computer ray-trace modeling of thin beds in salt reveals that the frequency and spatial resolution required to map the details of interbeds at shallow depths (less than 750 m) may be on the order of 500 Hz, with surface-spread lengths of less than 350 m. Consideration should be given to the burial of sources and receivers in order to attenuate surface noise and to record the desired high frequencies. Correlation of the seismic-reflection data with available well data and surface geology reveals the complex, structurally initiated diapir, whose upward flow was maintained by rapid contemporaneous deposition of continental clastic sediments on its flanks. Severe collapse faulting near the crests of these structures has distorted the seismic response. Evidence exists, however, that intrasalt thin beds of anhydrite, dolomite, and black shale are mappable on seismic record sections either as short, discontinuous reflected events or as amplitude anomalies that result from focusing of the reflected seismic energy by the thin beds; computer modeling of the folded interbeds confirms both of these as possible causes of seismic response from within the salt diapir. Prediction of the seismic signatures of the interbeds can be made from computer-model studies. Petroleum seismic-reflection data are unsatisfactory for

  9. Delineating priority habitat areas for the conservation of Andean bears in northern Ecuador

    USGS Publications Warehouse

    Peralvo, M.F.; Cuesta, F.; Van Manen, F.

    2005-01-01

    We sought to identify priority areas for the conservation of Andean bear (Tremarctos ornatus) habitat in the northern portion of the eastern Andean cordillera in Ecuador. The study area included pa??ramo and montane forest habitats within the Antisana and Cayambe-Coca ecological reserves, and unprotected areas north of these reserves with elevations ranging from 1,800 to 4,300 m. We collected data on bear occurrence along 53 transects during 2000-01 in the Oyacachi River basin, an area of indigenous communities within the Cayambe-Coca Ecological Reserve. We used those data and a set of 7 environmental variables to predict suitability of Andean bear habitat using Mahalanobis distance, a multivariate measure of dissimilarity. The Mahalanobis distance values were classified into 5 classes of habitat suitability and generalized to a resolution of 1,650-m ?? 1,650-m grid cells. Clusters of grid cells with high suitability values were delineated from the generalized model and denned as important habitat areas (IHAs) for conservation. The IHAs were ranked using a weighted index that included factors of elevation range, influence from disturbed areas, and current conservation status. We identified 12 IHAs, which were mainly associated with pa??ramo and cloud forest habitats; 2 of these areas have high conservation priorities because they are outside existing reserves and close to areas of human pressure. The distribution of the IHAs highlighted the role of human land use as the main source of fragmentation of Andean bear habitat in this region, emphasizing the importance of preserving habitat connectivity to allow the seasonal movements among habitat types that we documented for this species. Furthermore, the existence of areas with high habitat suitability close to areas of intense human use indicates the importance of bear-human conflict management as a critical Andean bear conservation strategy. We suggest that a promising conservation opportunity for this species is

  10. Global Biogeography of Reef Fishes: A Hierarchical Quantitative Delineation of Regions

    PubMed Central

    Kulbicki, Michel; Parravicini, Valeriano; Bellwood, David R.; Arias-Gonzàlez, Ernesto; Chabanet, Pascale; Floeter, Sergio R.; Friedlander, Alan; McPherson, Jana; Myers, Robert E.; Vigliola, Laurent; Mouillot, David

    2013-01-01

    Delineating regions is an important first step in understanding the evolution and biogeography of faunas. However, quantitative approaches are often limited at a global scale, particularly in the marine realm. Reef fishes are the most diversified group of marine fishes, and compared to most other phyla, their taxonomy and geographical distributions are relatively well known. Based on 169 checklists spread across all tropical oceans, the present work aims to quantitatively delineate biogeographical entities for reef fishes at a global scale. Four different classifications were used to account for uncertainty related to species identification and the quality of checklists. The four classifications delivered converging results, with biogeographical entities that can be hierarchically delineated into realms, regions and provinces. All classifications indicated that the Indo-Pacific has a weak internal structure, with a high similarity from east to west. In contrast, the Atlantic and the Eastern Tropical Pacific were more strongly structured, which may be related to the higher levels of endemism in these two realms. The “Coral Triangle”, an area of the Indo-Pacific which contains the highest species diversity for reef fishes, was not clearly delineated by its species composition. Our results show a global concordance with recent works based upon endemism, environmental factors, expert knowledge, or their combination. Our quantitative delineation of biogeographical entities, however, tests the robustness of the results and yields easily replicated patterns. The similarity between our results and those from other phyla, such as corals, suggests that our approach may be of broad utility in describing and understanding global marine biodiversity patterns. PMID:24386083

  11. Global biogeography of reef fishes: a hierarchical quantitative delineation of regions.

    PubMed

    Kulbicki, Michel; Parravicini, Valeriano; Bellwood, David R; Arias-Gonzàlez, Ernesto; Chabanet, Pascale; Floeter, Sergio R; Friedlander, Alan; McPherson, Jana; Myers, Robert E; Vigliola, Laurent; Mouillot, David

    2013-01-01

    Delineating regions is an important first step in understanding the evolution and biogeography of faunas. However, quantitative approaches are often limited at a global scale, particularly in the marine realm. Reef fishes are the most diversified group of marine fishes, and compared to most other phyla, their taxonomy and geographical distributions are relatively well known. Based on 169 checklists spread across all tropical oceans, the present work aims to quantitatively delineate biogeographical entities for reef fishes at a global scale. Four different classifications were used to account for uncertainty related to species identification and the quality of checklists. The four classifications delivered converging results, with biogeographical entities that can be hierarchically delineated into realms, regions and provinces. All classifications indicated that the Indo-Pacific has a weak internal structure, with a high similarity from east to west. In contrast, the Atlantic and the Eastern Tropical Pacific were more strongly structured, which may be related to the higher levels of endemism in these two realms. The "Coral Triangle", an area of the Indo-Pacific which contains the highest species diversity for reef fishes, was not clearly delineated by its species composition. Our results show a global concordance with recent works based upon endemism, environmental factors, expert knowledge, or their combination. Our quantitative delineation of biogeographical entities, however, tests the robustness of the results and yields easily replicated patterns. The similarity between our results and those from other phyla, such as corals, suggests that our approach may be of broad utility in describing and understanding global marine biodiversity patterns.

  12. Optimising delineation accuracy of tumours in PET for radiotherapy planning using blind deconvolution

    PubMed Central

    Guvenis, A.; Koc, A.

    2015-01-01

    Positron emission tomography (PET) imaging has been proven to be useful in radiotherapy planning for the determination of the metabolically active regions of tumours. Delineation of tumours, however, is a difficult task in part due to high noise levels and the partial volume effects originating mainly from the low camera resolution. The goal of this work is to study the effect of blind deconvolution on tumour volume estimation accuracy for different computer-aided contouring methods. The blind deconvolution estimates the point spread function (PSF) of the imaging system in an iterative manner in a way that the likelihood of the given image being the convolution output is maximised. In this way, the PSF of the imaging system does not need to be known. Data were obtained from a NEMA NU-2 IQ-based phantom with a GE DSTE-16 PET/CT scanner. The artificial tumour diameters were 13, 17, 22, 28 and 37 mm with a target/background ratio of 4:1. The tumours were delineated before and after blind deconvolution. Student's two-tailed paired t-test showed a significant decrease in volume estimation error (p < 0.001) when blind deconvolution was used in conjunction with computer-aided delineation methods. A manual delineation confirmation demonstrated an improvement from 26 to 16 % for the artificial tumour of size 37 mm while an improvement from 57 to 15 % was noted for the small tumour of 13 mm. Therefore, it can be concluded that blind deconvolution of reconstructed PET images may be used to increase tumour delineation accuracy. PMID:25836686

  13. SU-E-J-07: A Functional MR Protocol for the Pancreatic Tumor Delineation

    SciTech Connect

    Andreychenko, A; Heerkens, H; Meijer, G; Vulpen, M van; Lagendijk, J; Berg, C van den

    2014-06-01

    Purpose: Pancreatic cancer is one of the cancers with the poorest survival prognosis. At the time of diagnosis most of pancreatic cancers are unresectable and those patients can be treated by radiotherapy. Radiotherapy for pancreatic cancer is limited due to uncertainties in CT-based delineations. MRI provides an excellent soft tissue contrast. Here, an MR protocol is developed to improve delineations for radiotherapy treatment of pancreatic cancer. In a later stage this protocol can also be used for on-line visualization of the pancreas during MRI guided treatments. Methods: Nine pancreatic cancer patients were included. The MR protocol included T2 weighted(T2w), T1 weighted(T1w), diffusion weighted(DWI) and dynamic contrast enhanced(DCE) techniques. The tumor was delineated on T2w and T1w MRI by an experienced radiation oncologist. Healthy pancreas or pancreatitis (assigned by the oncologist based on T2w) areas were also delineated. Apparent diffusion coefficient(ADC), and area under the curve(AUC)/time to peak(TTP) maps were obtained from DWI and DCE scans, respectively. Results: A clear demarcation of tumor area was visible on b800 DWI images in 5 patients. ADC maps of those patients characterized tumor as an area with restricted water diffusion. Tumor delineations based on solely DCE were possible in 7 patients. In 6 of those patients AUC maps demonstrated tumor heterogeneity: a hypointense area with a hyperintense ring. TTP values clearly discriminated the tumor and the healthy pancreas but could not distinguish tumor and the pancreatitis accurately. Conclusion: MR imaging results in a more pronounced tumor contrast than contrast enhanced CT. The addition of quantitative, functional MRI provides valuable, additional information to the radiation oncologist on the spatial tumor extent by discriminating tumor from the healthy pancreas(TTP, DWI) and characterizing the tumor(ADC). Our findings indicate that tumor delineation in pancreatic cancer can greatly

  14. Delineation of Waters of the United States for Lawrence Livermore National Laboratory, Site 300

    SciTech Connect

    Preston, R E

    2006-09-25

    This report presents the results of a delineation of waters of the United States, including wetlands, for Lawrence Livermore National Laboratory's Site 300 in Alameda and San Joaquin Counties, California. Jones & Stokes mapped vegetation at Site 300 in August, 2001, using Global Positioning System (GPS) data recorders to collect point locations and to record linear features and map unit polygons. We identified wetlands boundaries in the field on the basis of the plant community present. We returned to collect additional information on wetland soils on July 3, 2002. Forty-six wetlands were identified, with a total area of 3.482 hectares (8.605 acres). The wetlands include vernal pools, freshwater seeps, and seasonal ponds. Wetlands appearing to meet the criteria for federal jurisdictional total 1.776 hectares (4.388 acres). A delineation map is presented and a table is provided with information on the type, size, characteristic plant species of each wetland, and a preliminary jurisdictional assessment.

  15. Integration of sewer system maps in topographically based sub-basin delineation in suburban areas

    NASA Astrophysics Data System (ADS)

    Jankowfsky, Sonja; Branger, Flora; Braud, Isabelle; Rodriguez, Fabrice

    2010-05-01

    Due to the increase of urbanization, suburban areas experience a fast change in land use. The impact of such modifications on the watershed hydrological cycle must be quantified. To achieve this goal, distributed hydrological models offer the possibility to take into account land use change, and more particularly to consider urbanized areas and anthropogenic features such as roads or ditches and their impact on the hydrological cycle. A detailed definition of the hydrographical drainage network and a corresponding delineation of sub-basins is therefore necessary as input to distributed models. Sub-basins in natural catchments are usually delineated using standard GIS based terrain analysis. The drainage network in urbanised watersheds is often modified, due to sewer systems, ditches, retention basins, etc.. Therefore, its delineation is not only determined by topography. The simple application of terrain analysis algorithms to delineate sub-basins in suburban areas can consequently lead to erroneous sub-basin borders. This study presents an improved approach for sub-basin delineation in suburban areas. It applies to small catchments connected to a sewage plant, located outside the catchment boundary. The approach assumes that subsurface flow follows topography. The method requires a digital elevation model (DEM), maps of land use, cadastre, sewer system and the location of measurement stations and retention basins. Firstly, the topographic catchment border must be defined for the concerning flow measurement station. Standard GIS based algorithms, like the d8-flow direction algorithm (O'Callaghan and Mark, 1984) can be applied using a high resolution DEM. Secondly, the artificial catchment outlets have to be determined. Each catchment has one natural outlet - the measurement station on the river- but it can have several artificial outlets towards a sewage station. Once the outlets are determined, a first approximation of the "theoretical maximal contributing area

  16. Body-wide hierarchical fuzzy modeling, recognition, and delineation of anatomy in medical images.

    PubMed

    Udupa, Jayaram K; Odhner, Dewey; Zhao, Liming; Tong, Yubing; Matsumoto, Monica M S; Ciesielski, Krzysztof C; Falcao, Alexandre X; Vaideeswaran, Pavithra; Ciesielski, Victoria; Saboury, Babak; Mohammadianrasanani, Syedmehrdad; Sin, Sanghun; Arens, Raanan; Torigian, Drew A

    2014-07-01

    To make Quantitative Radiology (QR) a reality in radiological practice, computerized body-wide Automatic Anatomy Recognition (AAR) becomes essential. With the goal of building a general AAR system that is not tied to any specific organ system, body region, or image modality, this paper presents an AAR methodology for localizing and delineating all major organs in different body regions based on fuzzy modeling ideas and a tight integration of fuzzy models with an Iterative Relative Fuzzy Connectedness (IRFC) delineation algorithm. The methodology consists of five main steps: (a) gathering image data for both building models and testing the AAR algorithms from patient image sets existing in our health system; (b) formulating precise definitions of each body region and organ and delineating them following these definitions; (c) building hierarchical fuzzy anatomy models of organs for each body region; (d) recognizing and locating organs in given images by employing the hierarchical models; and (e) delineating the organs following the hierarchy. In Step (c), we explicitly encode object size and positional relationships into the hierarchy and subsequently exploit this information in object recognition in Step (d) and delineation in Step (e). Modality-independent and dependent aspects are carefully separated in model encoding. At the model building stage, a learning process is carried out for rehearsing an optimal threshold-based object recognition method. The recognition process in Step (d) starts from large, well-defined objects and proceeds down the hierarchy in a global to local manner. A fuzzy model-based version of the IRFC algorithm is created by naturally integrating the fuzzy model constraints into the delineation algorithm. The AAR system is tested on three body regions - thorax (on CT), abdomen (on CT and MRI), and neck (on MRI and CT) - involving a total of over 35 organs and 130 data sets (the total used for model building and testing). The training and

  17. Delineation of a refined wellhead protection area for bedrock public supply wells, Charlestown, Rhode Island

    SciTech Connect

    Heath, D.L.

    1995-04-01

    This report describes the refined delineation of the Wellhead Protection Area (WHPA) of a wellfield of five public supply wells installed in granitic bedrock in Charlestown, Rhode Island, approximately 32 miles southwest of Providence, RI. The Rhode Island Department of Environmental Management (RIDEM) requested technical assistance from the USEPA-New England office to reevaluate the wellfield`s existing WHPA boundary with respect to the Charlestown Municipal Landfill, less than one mile upgradient from the wellfield. The Town of Charlestown, which owns the solid waste facility, was considering an areal expansion of the site. Based on the best available information, the refined wellhead protection area is approximately one-tenth the size of that delineated by the RIDEM. In addition, despite these modified size, a portion of the waste cell of the Charlestown Municipal Landfill apparently still lies within the refined WHPA.

  18. Use of LiDAR to Assist in Delineating Waters of the United States, Including Wetlands

    DTIC Science & Technology

    2014-03-01

    position in the land- scape. Wetness indices are often calculated using the general formula WI = ln(A/tanβ) where A is the catchment area (m2/m...delineations of an Ordinary High Water Mark (OHWM) boundary, LiDAR data or products may be used to view the OHWM signature across a project area ...view vegeta- tive, topographic, and hydrologic patterns across a project area and to focus the investigation on transitional areas . They cannot

  19. 372. J.W.M., Delineator August 1934 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    372. J.W.M., Delineator August 1934 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; CONTRACT NO. 6; SUPERSTRUCTURE - WEST BAY CROSSING; OUTSIDE ELEVATION OF HOUSING; CENTER ANCHORAGE - PIER NO. 4; AMERICAN BRIDGE CO.; AMBRIDGE PLANT; ORDER NO. G 4854-XI; SHEET NO. E8 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  20. Delineation of Methyl-DNA Binding Protein Interactions in the Prostate Cancer Genome

    DTIC Science & Technology

    2013-07-01

    Protein Interactions in the Prostate Cancer Genome PRINCIPAL INVESTIGATOR: Roderick T Hori, Ph.D...July 2012 – 30 June 2013 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Delineation of Methyl-DNA Binding Protein Interactions in the Prostate Cancer ...such as MeCP2, MBD1, MBD2 and MBD4, in malignant prostate cancer cells and matched normal or benign prostate cells using Chromatin

  1. Electromagnetic Delineation and Confirmation of Areas of Groundwater-Surface Water Interaction in a Large River

    NASA Astrophysics Data System (ADS)

    Nadeau, J.; Dawe, M. R.; Butler, K. E.; Macquarrie, K. T.

    2004-05-01

    Riverbank filtration systems are typically located in heterogeneous alluvial river valley deposits. Delineation of riverbed areas where there is downward river water infiltration is important for determining the fluxes, quality, and travel time of water supplied to production wells. Efficient methods of delineation are especially required in large rivers that may also have relatively large water depths. A portion of the City of Fredericton well field recharge zone lies beneath the adjacent Saint John River, where a discontinuity in the clay/silt aquitard may allow hydraulic connection between the esker-like aquifer and the river. In this project we have investigated the potential for using electromagnetic methods to delineate zones of low electrical conductivity. Such zones, in a fresh water environment, suggest the absence of clay/silt materials. During the summers of 2001 and 2002, a total of 120 km of electromagnetic data were acquired using the Geonics EM31 and EM34 ground conductivity meters. The survey was carried out using an outboard-motor-powered canoe and raft with onboard DGPS system. Both electromagnetic instruments were operated in the vertical dipole mode, thereby providing maximum depths of exploration of approximately 30 meters. The water depths in the survey area fall in the range where the EM31 and EM34 results are very sensitive to the conductivity structure. We applied a novel bathymetry correction approach to compensate for water depth effects. Contouring of the apparent conductivity data revealed a conductivity low with an approximate area of 6 hectares. The absence of the clay/silt aquitard was confirmed by high resolution seismic profiling and drilling and sampling of riverbed sediments. Further confirmation of river water infiltration has been provided by hydraulic data from mini-piezometers and temperature time series collected beneath the riverbed. Apparent conductivity mapping proved to be a sensitive and efficient method for delineating

  2. Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region

    DTIC Science & Technology

    2006-12-01

    alternative sampling techniques are used, they should be described in field notes or in the delineation report. The basic data must include...information on these techniques . Growing season Beginning and ending dates of the growing season are needed to evaluate certain wetland indicators, such...Sediment deposits are thin layers or coatings of fine-grained mineral material (e.g., silt or clay) or organic matter (e.g., pollen ), sometimes mixed

  3. Relationship between Myers-Briggs Type Indicator and Gregorc Style Delineator.

    PubMed

    Harasym, P H; Leong, E J; Juschka, B B; Lucier, G E; Lorscheider, F L

    1996-06-01

    The relationship between the Myers-briggs Type Indicator and Gregorc Style Delineator, and achievement was examined by administering these instruments to 259 first-year nursing students enrolled in an introductory human anatomy and physiology course. A principal component factor analysis using a varimax rotation of the scores from the two psychometric instruments, achievement examinations and an over-all grade point average indicated that each learning style from the Gregorc Style Delineator corresponds to certain traits on the Myers-Briggs Type Indicator. An individual who had a preference for the learning style of Concrete Sequential tended to have the traits of sensing and judging on the Myers-Briggs Type Indicator, while an individual who used the learning style of Concrete Random tended to have the traits of intuition and perceiving on the Myers-Briggs Type Indicator. One who had a preference for the learning style of Abstract Sequential tended to use the trait of thinking while another who used the learning style of Abstract Random tended to have the trait of feeling. The factor analysis also indicates no relationship of any scores of the traits on the Myers-Briggs Type Indicator or learning styles of the Gregorc Style Delineator with the examination scores achieved in the human anatomy and physiology course or to the students' over-all grade point average. However, factor analysis indicates that the Myers-Briggs Type Indicator traits of Judging vs Perceiving collapsed into the Sensing vs Intuition scale, and that the Gregorc Style Delineator consists of two bipolar scales that are different from those proposed by Gregorc.

  4. Iterative Otsu's method for OCT improved delineation in the aorta wall

    NASA Astrophysics Data System (ADS)

    Alonso, Daniel; Real, Eusebio; Val-Bernal, José F.; Revuelta, José M.; Pontón, Alejandro; Calvo Díez, Marta; Mayorga, Marta; López-Higuera, José M.; Conde, Olga M.

    2015-07-01

    Degradation of human ascending thoracic aorta has been visualized with Optical Coherence Tomography (OCT). OCT images of the vessel wall exhibit structural degradation in the media layer of the artery, being this disorder the final trigger of the pathology. The degeneration in the vessel wall appears as low-reflectivity areas due to different optical properties of acidic polysaccharides and mucopolysaccharides in contrast with typical ordered structure of smooth muscle cells, elastin and collagen fibers. An OCT dimension indicator of wall degradation can be generated upon the spatial quantification of the extension of degraded areas in a similar way as conventional histopathology. This proposed OCT marker can offer in the future a real-time clinical perception of the vessel status to help cardiovascular surgeons in vessel repair interventions. However, the delineation of degraded areas on the B-scan image from OCT is sometimes difficult due to presence of speckle noise, variable signal to noise ratio (SNR) conditions on the measurement process, etc. Degraded areas can be delimited by basic thresholding techniques taking advantage of disorders evidences in B-scan images, but this delineation is not optimum in the aorta samples and requires complex additional processing stages. This work proposes an optimized delineation of degraded areas within the aorta wall, robust to noisy environments, based on the iterative application of Otsu's thresholding method. Results improve the delineation of wall anomalies compared with the simple application of the algorithm. Achievements could be also transferred to other clinical scenarios: carotid arteries, aorto-iliac or ilio-femoral sections, intracranial, etc.

  5. Description and application of capture zone delineation for a wellfield at Hilton Head Island, South Carolina

    USGS Publications Warehouse

    Landmeyer, J.E.

    1994-01-01

    Ground-water capture zone boundaries for individual pumped wells in a confined aquffer were delineated by using groundwater models. Both analytical and numerical (semi-analytical) models that more accurately represent the $round-water-flow system were used. All models delineated 2-dimensional boundaries (capture zones) that represent the areal extent of groundwater contribution to a pumped well. The resultant capture zones were evaluated on the basis of the ability of each model to realistically rapresent the part of the ground-water-flow system that contributed water to the pumped wells. Analytical models used were based on a fixed radius approach, and induded; an arbitrary radius model, a calculated fixed radius model based on the volumetric-flow equation with a time-of-travel criterion, and a calculated fixed radius model derived from modification of the Theis model with a drawdown criterion. Numerical models used induded the 2-dimensional, finite-difference models RESSQC and MWCAP. The arbitrary radius and Theis analytical models delineated capture zone boundaries that compared least favorably with capture zones delineated using the volumetric-flow analytical model and both numerical models. The numerical models produced more hydrologically reasonable capture zones (that were oriented parallel to the regional flow direction) than the volumetric-flow equation. The RESSQC numerical model computed more hydrologically realistic capture zones than the MWCAP numerical model by accounting for changes in the shape of capture zones caused by multiple-well interference. The capture zone boundaries generated by using both analytical and numerical models indicated that the curnmtly used 100-foot radius of protection around a wellhead in South Carolina is an underestimate of the extent of ground-water capture for pumped wetis in this particular wellfield in the Upper Floridan aquifer. The arbitrary fixed radius of 100 feet was shown to underestimate the upgradient

  6. Delineating Floodplain in North Korea using Remote Sensing and Geographic Information System

    NASA Astrophysics Data System (ADS)

    Lim, J.; Lee, K. S.

    2015-12-01

    Korea has been divided into two countries after World War II. So environmental studies about North Korean are not easy and very limited. There were several flood damages every summer in North Korea since 1995, which induces lots of economic loss and agricultural production decrease. Delineating floodplain is indispensable to estimate the magnitude of flood damage and restore the flooded paddy field after unification. Remote Sensing (RS) can provide opportunity to study inaccessible area. In addition, flooding detection is possible. Several research groups study about flooding disaster using RS. Optical images and microwave images have been used in that field. Also, Digital topographic data have been used for flooding detection. Therefore, the purpose of this study is to investigate the land characteristics of floodplain by delineating floodplain in inaccessible North Korea using Landsat and digital topographic data. Landsat TM 5 images were used in this study. North Korea had severe flooding disaster since 1995. Among them 1995, 2007 and 2012 flooding are known for serious damages. Two Landsat images before and after flooding of each year were used to delineate floodplain. Study areas are Pyongyang City, Nampo City, North and South Hwanghae Province and South Pyongan Province. Floodplain are derived from overlaid classification image and flood-depth map. 1:25,000 scale digital topographic data were used to make flood-depth map. For land cover classification image enhancement and supervised classification with maximum likelihood classifier were used. Training areas were selected by visual interpretation using Daum-map which provides high resolution image of whole North Korea. The spatial characteristics of the floodplain were discussed based on floodplain map delineated in this study.

  7. Growing Season Definition and Use in Wetland Delineation: A Literature Review

    DTIC Science & Technology

    2010-08-01

    also indicate that the alpine tundra microbial community has a high resistance to freeze–thaw and dry–rewet events, in contrast to studies in other...Lacking direct information on soil temperatures, minimum air temperature thresholds are used as indicators of the beginning and ending dates for the...basis of careful scientific study of natural wetland communities and processes.” Currently, there are ten USACE regional wetland delineation

  8. Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Great Plans Region

    DTIC Science & Technology

    2008-03-01

    limited to unvegetated playa lakes , mud and salt flats, and perennial, intermittent, and ephemeral stream channels. Delineation of these waters in non...drifts; glacial lake sediments; wind-deposited loess and sands; residuum from the weathering of shales, sandstones, and limestones; mountain out- washes...fens, seeps, fringe wetlands surrounding lakes and reservoirs, prairie potholes, playa lakes , and other fresh and saline depressional systems (Comer

  9. Using SAR Interferograms and Coherence Images for Object-Based Delineation of Unstable Slopes

    NASA Astrophysics Data System (ADS)

    Friedl, Barbara; Holbling, Daniel

    2015-05-01

    This study uses synthetic aperture radar (SAR) interferometric products for the semi-automated identification and delineation of unstable slopes and active landslides. Single-pair interferograms and coherence images are therefore segmented and classified in an object-based image analysis (OBIA) framework. The rule-based classification approach has been applied to landslide-prone areas located in Taiwan and Southern Germany. The semi-automatically obtained results were validated against landslide polygons derived from manual interpretation.

  10. Delineation of Areas Contributing Water to the Dry Brook Public-Supply Well, South Hadley, Massachusetts

    USGS Publications Warehouse

    Garabedian, Stephen P.; Stone, Janet Radway

    2004-01-01

    gravel aquifer near the Dry Brook well, which is consistent with the geologic information. Results of aquifer-test simulation indicated that spatially variable aquifer hydraulic properties and boundary conditions affected heads and ground-water flow near the well. A comparison and analysis of water-level fluctuations in study area wells to fluctuations in the Connecticut River indicated a hydraulic connection of the aquifer with the river, which is also consistent with geologic information. Simulated ground-water levels indicated that most ground water in the study area flowed toward and discharged to the Connecticut River and the Dry Brook well. Small amounts of ground water also discharged to smaller streams (Dry Brook and Bachelor Brook) in the study area. Areas contributing water to the well were delineated with the MODPATH particle-tracking routine. Results of the contributing-area analysis indicated that the greatest sources of water to the well were recharge in the Dry Brook Hill area and infiltration of Connecticut River water in an area beyond the extent of the confining bed where the aquifer is in hydraulic connection with the river. The amount of water entering the Dry Brook well from recharge dominated at a lower pumping rate (40.0 ft3/min); about 90 percent of the pumped water originated from recharge and boundary flow, and infiltration from the Connecticut River supplied the remaining 10 percent. At a high pumping rate (122.2 ft3/min), however, about half of the water pumped from the Dry Brook well originated from recharge and boundary flow (49 percent), and half originated from infiltration of water from the Connecticut River (51 percent). Results of a sensitivity analysis of the extent of areas contributing water to the Dry Brook well when pumped at 122.2 ft3/min indicated that the size of these areas did not substantially change when aquifer properties were varied. In contrast, however, the size of these areas changed most when the recharge

  11. Delineating Species with DNA Barcodes: A Case of Taxon Dependent Method Performance in Moths

    PubMed Central

    Kekkonen, Mari; Mutanen, Marko; Kaila, Lauri; Nieminen, Marko; Hebert, Paul D. N.

    2015-01-01

    The accelerating loss of biodiversity has created a need for more effective ways to discover species. Novel algorithmic approaches for analyzing sequence data combined with rapidly expanding DNA barcode libraries provide a potential solution. While several analytical methods are available for the delineation of operational taxonomic units (OTUs), few studies have compared their performance. This study compares the performance of one morphology-based and four DNA-based (BIN, parsimony networks, ABGD, GMYC) methods on two groups of gelechioid moths. It examines 92 species of Finnish Gelechiinae and 103 species of Australian Elachistinae which were delineated by traditional taxonomy. The results reveal a striking difference in performance between the two taxa with all four DNA-based methods. OTU counts in the Elachistinae showed a wider range and a relatively low (ca. 65%) OTU match with reference species while OTU counts were more congruent and performance was higher (ca. 90%) in the Gelechiinae. Performance rose when only monophyletic species were compared, but the taxon-dependence remained. None of the DNA-based methods produced a correct match with non-monophyletic species, but singletons were handled well. A simulated test of morphospecies-grouping performed very poorly in revealing taxon diversity in these small, dull-colored moths. Despite the strong performance of analyses based on DNA barcodes, species delineated using single-locus mtDNA data are best viewed as OTUs that require validation by subsequent integrative taxonomic work. PMID:25849083

  12. An efficient approach to 3D single tree-crown delineation in LiDAR data

    NASA Astrophysics Data System (ADS)

    Mongus, Domen; Žalik, Borut

    2015-10-01

    This paper proposes a new method for 3D delineation of single tree-crowns in LiDAR data by exploiting the complementaries of treetop and tree trunk detections. A unified mathematical framework is provided based on the graph theory, allowing for all the segmentations to be achieved using marker-controlled watersheds. Treetops are defined by detecting concave neighbourhoods within the canopy height model using locally fitted surfaces. These serve as markers for watershed segmentation of the canopy layer where possible oversegmentation is reduced by merging the regions based on their heights, areas, and shapes. Additional tree crowns are delineated from mid- and under-storey layers based on tree trunk detection. A new approach for estimating the verticalities of the points' distributions is proposed for this purpose. The watershed segmentation is then applied on a density function within the voxel space, while boundaries of delineated trees from the canopy layer are used to prevent the overspreading of regions. The experiments show an approximately 6% increase in the efficiency of the proposed treetop definition based on locally fitted surfaces in comparison with the traditionally used local maxima of the smoothed canopy height model. In addition, 4% increase in the efficiency is achieved by the proposed tree trunk detection. Although the tree trunk detection alone is dependent on the data density, supplementing it with the treetop detection the proposed approach is efficient even when dealing with low density point-clouds.

  13. Frameless neuronavigation using the ISG-system in practice: from craniotomy to delineation of lesion.

    PubMed

    Kleinpeter, G; Lothaller, C

    2003-10-01

    The overall performance of a "pointer" neuronavigation system (the ISG ALLEGRO Viewing Wand) in everyday surgical use was evaluated by investigating the practical utility of the technical set-up for one particular surgical task. The basis of the analysis was the numerical evaluation of four areas of fundamental importance for most brain surgery: site and size of craniotomy, localisation of lesion, the trajectory through the brain, and the delineation of the lesion. In a protocol of 65 patients we based our examination on a subjective 4-point rating scale ranging from 0 (= no help) to 3 (= very helpful) for each of the four above categories. We investigated the potential influence of three factors: the lesions histology (4 groups), its size (3 categories) and the depth from the cortical surface (3 levels). Our experience is that the histology of the lesions has significant influence on the relative usefulness of neuronavigation for craniotomy (P < 0.017) and for delineation of the lesion (P < 0.003). We found neuronavigation most helpful for removing gliomas. Second, this system was found to be very helpful in locating small, hitherto hard-to-find, lesions (P < 0.01). Lesion's depth had no effect on the ratings (P > 0.2). Overall, the use of this system led to more precise skin incisions, better site and size of craniotomies tailored to the pathology, the trajectory through the brain, and to more precise delineation of the lesion.

  14. Modeling fire susceptibility to delineate wildland-urban interface for municipal-scale fire risk management.

    PubMed

    Whitman, Ellen; Rapaport, Eric; Sherren, Kate

    2013-12-01

    The wildland-urban interface (WUI) is the region where development meets and intermingles with wildlands. The WUI has an elevated fire risk due to the proximity of development and residents to wildlands with natural wildfire regimes. Existing methods of delineating WUI are typically applied over a large region, use proxies for risk, and do not consider site-specific fire hazard drivers. While these models are appropriate for federal and provincial risk management, municipal managers require models intended for smaller regions. The model developed here uses the Burn-P3 fire behavior model to model WUI from local fire susceptibility (FS) in two study communities. Forest fuel code (FFC) maps for the study communities were modified using remote sensing data to produce detailed forest edges, including ladder fuels, update data currency, and add buildings and roads. The modified FFC maps used in Burn-P3 produced bimodal FS distributions for each community. The WUI in these communities was delineated as areas within community bounds where FS was greater than or equal to -1 SD from the mean FS value ([Formula: see text]), which fell in the trough of the bimodal distribution. The WUI so delineated conformed to the definition of WUI. This model extends WUI modeling for broader risk management initiatives for municipal management of risk, as it (a) considers site-specific drivers of fire behavior; (b) models risk, represented by WUI, specific to a community; and, (c) does not use proxies for risk.

  15. Delineating spring recharge areas in a fractured sandstone aquifer (Luxembourg) based on pesticide mass balance

    NASA Astrophysics Data System (ADS)

    Farlin, J.; Drouet, L.; Gallé, T.; Pittois, D.; Bayerle, M.; Braun, C.; Maloszewski, P.; Vanderborght, J.; Elsner, M.; Kies, A.

    2013-06-01

    A simple method to delineate the recharge areas of a series of springs draining a fractured aquifer is presented. Instead of solving the flow and transport equations, the delineation is reformulated as a mass balance problem assigning arable land in proportion to the pesticide mass discharged annually in a spring at minimum total transport cost. The approach was applied to the Luxembourg Sandstone, a fractured-rock aquifer supplying half of the drinking water for Luxembourg, using the herbicide atrazine. Predictions of the recharge areas were most robust in situations of strong competition by neighbouring springs while the catchment boundaries for isolated springs were extremely sensitive to the parameter controlling flow direction. Validation using a different pesticide showed the best agreement with the simplest model used, whereas using historical crop-rotation data and spatially distributed soil-leaching data did not improve predictions. The whole approach presents the advantage of integrating objectively information on land use and pesticide concentration in spring water into the delineation of groundwater recharge zones in a fractured-rock aquifer.

  16. Fast automatic delineation of cardiac volume of interest in MSCT images

    NASA Astrophysics Data System (ADS)

    Lorenz, Cristian; Lessick, Jonathan; Lavi, Guy; Bulow, Thomas; Renisch, Steffen

    2004-05-01

    Computed Tomography Angiography (CTA) is an emerging modality for assessing cardiac anatomy. The delineation of the cardiac volume of interest (VOI) is a pre-processing step for subsequent visualization or image processing. It serves the suppression of anatomic structures being not in the primary focus of the cardiac application, such as sternum, ribs, spinal column, descending aorta and pulmonary vasculature. These structures obliterate standard visualizations such as direct volume renderings or maximum intensity projections. In addition, outcome and performance of post-processing steps such as ventricle suppression, coronary artery segmentation or the detection of short and long axes of the heart can be improved. The structures being part of the cardiac VOI (coronary arteries and veins, myocardium, ventricles and atria) differ tremendously in appearance. In addition, there is no clear image feature associated with the contour (or better cut-surface) distinguishing between cardiac VOI and surrounding tissue making the automatic delineation of the cardiac VOI a difficult task. The presented approach locates in a first step chest wall and descending aorta in all image slices giving a rough estimate of the location of the heart. In a second step, a Fourier based active contour approach delineates slice-wise the border of the cardiac VOI. The algorithm has been evaluated on 41 multi-slice CT data-sets including cases with coronary stents and venous and arterial bypasses. The typical processing time amounts to 5-10s on a 1GHz P3 PC.

  17. Photo-acoustic imaging of blue nanoparticle targeted brain tumor for intra-operative glioma delineation

    NASA Astrophysics Data System (ADS)

    Ray, Aniruddha; Wang, Xueding; Koo Lee, Yong-Eun; Hah, HoeJin; Kim, Gwangseong; Chen, Thomas; Orrienger, Daniel; Sagher, Oren; Kopelman, Raoul

    2011-07-01

    Distinguishing the tumor from the background neo-plastic tissue is challenging for cancer surgery such as surgical resection of glioma. Attempts have been made to use visible or fluorescent markers to delineate the tumors during surgery. However, the systemic injection of the dyes requires high dose, resulting in negative side effects. A novel method to delineate rat brain tumors intra-operatively, as well as post-operatively, using a highly sensitive photoacoustic imaging technique enhanced by tumor targeting blue nanoparticle as contrast agent is demonstrated. The nanoparticles are made of polyacrylamide (PAA) matrix with covalently linked Coomassie-Blue dye. They contain 7.0% dye and the average size is 80nm. Their surface was conjugated with F3 peptide for active tumor targeting. These nanoparticles are nontoxic, chemically inert and have long plasma circulation lifetime, making them suitable as nanodevices for imaging using photoacoustics. Experiments on phantoms and rat brains tumors ex-vivo demonstrate the high sensitivity of photoacoustic imaging in delineating the tumor, containing contrast agent at concentrations too low to be visualized by eye. The control tumors without nanoparticles did not show any enhanced signal. This study shows that photoacoustic imaging facilitated with the nanoparticle contrast agent could contribute to future surgical procedures for glioma.

  18. Delineation of creosote-based DNAPLs using CPT-deployed laser induced fluorescence

    SciTech Connect

    Ruggery, D.A. Jr.; Misquitta, N.J; Coll, F.R..

    1996-12-01

    This paper presents a case study of the first commercial use of cone penetrometer testing (CPT)/deployed laser induced fluorescence (LIF) to address the following objectives at a creosote DNAPL site. The objectives of the investigation using CPT/LIF were to: quickly and cost effectively delineate the horizontal and vertical extent of creosote DNAPL in soil/groundwater; delineate/differentiate creosote DNAPL constituents within the extent of DNAPL; delineate dissolved-phase versus free phase DNAPL compounds in the subsurface. The complexity of investigating the extent of creosote DNAPL magnifies the time and cost of the application of conventional investigative techniques. The application of CPT/LIF at the subject site allowed a comparison between CPT/LIF and more conventional investigative techniques. If the objectives were achieved in a shorter time-frame, and at a lesser cost than traditional methods, then the CPT/LIF method would be confirmed as a viable, field-scale technology for investigating appropriate wood-treating sites.

  19. Methodology of delineating wellhead protection zones in crystalline bedrock in Maine

    USGS Publications Warehouse

    Lipfert, G.; Tolman, A.L.; Loiselle, M.C.

    2004-01-01

    Delineation of contributing areas for wellhead protection around supply wells drilled into bedrock in Maine, USA, is currently achieved by assigning a fixed radius circle around the well. This project develops a methodology that incorporates hydrogeologic processes and ground water modeling (MODFLOW) and accounts for variable data availability to estimate the areas that contribute water to 26 bedrock supply wells. Outcrop fracture mapping and lineament analysis are used to characterize the fracture system. Multiple simulations are constructed of each site using ranges of values for recharge, hydraulic conductivity, and anisotropy. Uncertainty in the delineation process is accounted for by portraying the delineated areas as confidence zones that are constructed by overlapping the capture zones from the multiple simulations. The results are variable and depend on the ability to characterize a site in a way that can be easily modeled. Sites with complex hydrogeology tend to have larger contributing areas that reflect the greater uncertainty in the parameters. The majority of the sites, however, produce reasonable results that provide a much more accurate depiction of the area likely to contribute to a bedrock well than the fixed radius circle.

  20. A tree canopy height delineation method based on Morphological Reconstruction—Open Crown Decomposition

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Jing, L.; Li, Y.; Tang, Y.; Li, H.; Lin, Q.

    2016-04-01

    For the purpose of forest management, high resolution LIDAR and optical remote sensing imageries are used for treetop detection, tree crown delineation, and classification. The purpose of this study is to develop a self-adjusted dominant scales calculation method and a new crown horizontal cutting method of tree canopy height model (CHM) to detect and delineate tree crowns from LIDAR, under the hypothesis that a treetop is radiometric or altitudinal maximum and tree crowns consist of multi-scale branches. The major concept of the method is to develop an automatic selecting strategy of feature scale on CHM, and a multi-scale morphological reconstruction-open crown decomposition (MRCD) to get morphological multi-scale features of CHM by: cutting CHM from treetop to the ground; analysing and refining the dominant multiple scales with differential horizontal profiles to get treetops; segmenting LiDAR CHM using watershed a segmentation approach marked with MRCD treetops. This method has solved the problems of false detection of CHM side-surface extracted by the traditional morphological opening canopy segment (MOCS) method. The novel MRCD delineates more accurate and quantitative multi-scale features of CHM, and enables more accurate detection and segmentation of treetops and crown. Besides, the MRCD method can also be extended to high optical remote sensing tree crown extraction. In an experiment on aerial LiDAR CHM of a forest of multi-scale tree crowns, the proposed method yielded high-quality tree crown maps.

  1. [Guidelines for delineation of pelvic lymph nodes in anal cancer treatment].

    PubMed

    Vendrely, V; Galland-Girodet, S; Orré, M; Maire, J-P

    2013-10-01

    Squamous cell anal cancer is a rare malignancy, its incidence increases due to higher exposure of the young adults to risk factors. The current management is based on chemoradiotherapy, which is highly effective and achieves locoregional control but causes important morbidity. Improvement of radiation technique such as intensity modulated radiation therapy has led to reduce acute toxicities, but also requires an accurate delineation of the target volumes in order not to underestimate potential and pathological sites resulting in an increase of the locoregional failures. PET scanner has an important place in the pretreatment work-up for staging and targeting the delineation of the volumes, allowing to select patients with localized disease, avoid geographic miss and appropriately boost nodal disease. The study of recurrences sites has not yet provided a real mapping of the recurrences depending on the treatment volumes. Different radiation oncologist cooperative groups have published guidelines and tools for delineation, in order to provide homogeneity but also customize the management of anal carcinoma.

  2. Maritime Route Delineation using AIS Data from the Atlantic Coast of the US

    SciTech Connect

    Breithaupt, Stephen A.; Copping, Andrea; Tagestad, Jerry; Whiting, Jonathan

    2016-09-28

    This study examines maritime routes between ports along the Atlantic coast of the US, utilising Automated Identification System (AIS) data for the years 2010 through 2012. The delineation of vessel routes conducted in this study was motivated by development planned for offshore Wind Energy Areas (WEAs) along the Atlantic coast of the US and the need to evaluate the effect of these development areas on commercial shipping. To this end, available AIS data were processed to generate commercial vessel tracks for individual vessels, though cargo vessels are the focus in this study. The individual vessel tracks were sampled at transects placed along the Atlantic coast. The transect samples were analysed and partitioned by voyages between Atlantic ports to facilitate computation of vessel routes between ports. The route boundary analysis utilised a definition from UK guidance in which routes' boundaries encompassed 95% of the vessel traffic between ports. In addition to delineating route boundaries, we found multi-modal transverse distributions of vessels for well-travelled routes, which indicated preference for lanes of travel within the delineated routes.

  3. Geographic delineations of yeast communities and populations associated with vines and wines in New Zealand

    PubMed Central

    Gayevskiy, Velimir; Goddard, Matthew R

    2012-01-01

    Yeasts are a diverse seemingly ubiquitous group of eukaryotic microbes, and many are naturally associated with fruits. Humans have harnessed yeasts since the dawn of civilisation to make wine, and thus it is surprising that we know little of the distribution of yeast communities naturally associated with fruits. Previous reports of yeast community diversity have been descriptive only. Here we present, we believe, the first robust test for the geographic delineation of yeast communities. Humans have relatively recently employed Saccharomyces cerevisiae as a model research organism, and have long harnessed its ancient adaption to ferment even in the presence of oxygen. However, as far as we are aware, there has not been a rigorous test for the presence of regional differences in natural S. cerevisiae populations before. We combined these community- and population-level questions and surveyed replicate vineyards and corresponding spontaneous ferments from different regions on New Zealand's (NZ's) North Island and analysed the resulting data with community ecology and population genetic tests. We show that there are distinct regional delineations of yeast communities, but the picture for S. cerevisiae is more complex: there is evidence for region-specific sub-populations but there are also reasonable levels of gene flow among these regions in NZ. We believe this is the first demonstration of regional delineations of yeast populations and communities worldwide. PMID:22189497

  4. Using aquatic invertebrates to delineate seasonal and temporary wetlands in the Prairie Pothole Region of North America

    USGS Publications Warehouse

    Euliss, Ned H.; Mushet, David M.; Johnson, Douglas H.

    2002-01-01

    Tillage can destroy or greatly disturb indicators of hydric soils and hydrophytic vegetation, making delineation of tilled wetlands difficult. The remains of aquatic invertebrates (e.g., shells, drought-resistant eggs, and trichopteran cases) are easily identifiable and persist in wetland substrates even when wetlands are dry. Additionally, these remains are not easily destroyed by mechanical tillage. To test the feasibility of using invertebrate remains to delineate wetlands, we used two methods to identify the wetland edge of ten seasonal and ten temporary wetlands, evenly divided between grassland and cropland landscapes. First, we identified the wetland edge using hydric soil and vegetation indicators along six evenly spaced transects in each wetland (our “standard” delineation). We then identified the wetland edge along the same transects using aquatic invertebrate remains as our indicator. In grassland landscapes, delineations of the wetland edge made using invertebrate remains were consistently at the same location or closer to the wetland center as the standard delineations for both seasonal and temporary wetlands. In cropland landscapes, however, many of our invertebrate delineations of seasonal and temporary wetlands were on the upland side of our standard delineations. We attribute the differences to movement of remains during tillage, increased maximum pool levels in cropland wetlands, and disturbance of hydric soils and plants. We found that the elevations of the wetland edge indicated by invertebrate remains were more consistent within a wetland than elevations determined by standard delineations. Aquatic invertebrate remains can be useful in delineating wetlands when other indicators have been destroyed or severely disturbed by tillage.

  5. Target Volume Delineation in Dynamic Positron Emission Tomography Based on Time Activity Curve Differences

    NASA Astrophysics Data System (ADS)

    Teymurazyan, Artur

    Tumor volume delineation plays a critical role in radiation treatment planning and simulation, since inaccurately defined treatment volumes may lead to the overdosing of normal surrounding structures and potentially missing the cancerous tissue. However, the imaging modality almost exclusively used to determine tumor volumes, X-ray Computed Tomography (CT), does not readily exhibit a distinction between cancerous and normal tissue. It has been shown that CT data augmented with PET can improve radiation treatment plans by providing functional information not available otherwise. Presently, static PET scans account for the majority of procedures performed in clinical practice. In the radiation therapy (RT) setting, these scans are visually inspected by a radiation oncologist for the purpose of tumor volume delineation. This approach, however, often results in significant interobserver variability when comparing contours drawn by different experts on the same PET/CT data sets. For this reason, a search for more objective contouring approaches is underway. The major drawback of conventional tumor delineation in static PET images is the fact that two neighboring voxels of the same intensity can exhibit markedly different overall dynamics. Therefore, equal intensity voxels in a static analysis of a PET image may be falsely classified as belonging to the same tissue. Dynamic PET allows the evaluation of image data in the temporal domain, which often describes specific biochemical properties of the imaged tissues. Analysis of dynamic PET data can be used to improve classification of the imaged volume into cancerous and normal tissue. In this thesis we present a novel tumor volume delineation approach (Single Seed Region Growing algorithm in 4D (dynamic) PET or SSRG/4D-PET) in dynamic PET based on TAC (Time Activity Curve) differences. A partially-supervised approach is pursued in order to allow an expert reader to utilize the information available from other imaging

  6. Coverage-based treatment planning to accommodate delineation uncertainties in prostate cancer treatment

    PubMed Central

    Xu, Huijun; Gordon, J. James; Siebers, Jeffrey V.

    2015-01-01

    Purpose: To compare two coverage-based planning (CP) techniques with fixed margin-based (FM) planning for high-risk prostate cancer treatments, with the exclusive consideration of the dosimetric impact of delineation uncertainties of target structures and normal tissues. Methods: In this work, 19-patient data sets were involved. To estimate structure dose for each delineated contour under the influence of interobserver contour variability and CT image quality limitations, 1000 alternative structures were simulated by an average-surface-of-standard-deviation model, which utilized the patient-specific information of delineated structure and CT image contrast. An IMRT plan with zero planning-target-volume (PTV) margin on the delineated prostate and seminal vesicles [clinical-target-volume (CTVprostate) and CTVSV] was created and dose degradation due to contour variability was quantified by the dosimetric consequences of 1000 alternative structures. When D98 failed to achieve a 95% coverage probability objective D98,95 ≥ 78 Gy (CTVprostate) or D98,95 ≥ 66 Gy (CTVSV), replanning was performed using three planning techniques: (1) FM (PTVprostate margin = 4,5,6 mm and PTVSV margin = 4,5,7 mm for RL, PA, and SI directions, respectively), (2) CPOM which optimized uniform PTV margins for CTVprostate and CTVSV to meet the D98,95 objectives, and (3) CPCOP which directly optimized coverage-based objectives for all the structures. These plans were intercompared by computing percentile dose-volume histograms and tumor-control probability/normal tissue complication probability (TCP/NTCP) distributions. Results: Inherent contour variability resulted in unacceptable CTV coverage for the zero-PTV-margin plans for all patients. For plans designed to accommodate contour variability, 18/19 CP plans were most favored by achieving desirable D98,95 and TCP/NTCP values. The average improvement of probability of complication free control was 9.3% for CPCOP plans and 3.4% for CPOM plans

  7. Investigation of SRTM Data for Delineation of Process Relevant Response Units in Different Landscapes

    NASA Astrophysics Data System (ADS)

    Wolf, M.; Pfennig, B.

    2007-12-01

    The concept of this research is justified to the integration of landscape components for hydrological modelling within distributed models. Distributed models are based on homogenous entities which are delineated using landscape parameters such as topography, land use, soil, and geology. In ungauged basins most of these required data are only available on a coarse spatial resolution. In order to by-pass this gap the globally and freely available data from the Shuttle Radar Topography Mission (SRTM) were used to obtain model entities on a finer resolution because this data have an adequate resolution of 30m and 90m. The method relies on the assumption of a strong, process-driven feedback between the topography and further landscape components as well as runoff dynamics. It is expected that the water balance of catchments with insufficient data availability can be estimated using SRTM-based delineations of process-oriented model entities. A main goal is the investigation of the SRTM-data for delineation of process relevant response units (RU) over various scales. In order to correct geometric and radiometric errors the SRTM-data were optimized using several GIS procedures and new algorithms for void filling, vegetation reduction, hydrological oriented filter combinations and stream burning. A new developed sink fill method was implemented with the name LaSA (Landscape based Sink Algorithm). Elimination of sinks should be realized by a landscape-based optimum between filling sinks and carving of flow paths in flow barriers. In result of DEM preparation, hydrological corrected elevation data were available to establish a ruled-based framework for RU-delineation. Numerous topographic indices were applied whereas the index selection was oriented on different relief driven processes. The resulting datasets were analysed by the Cluster Analysis IVHG. Finally, different patterns of process driven RU, combing various topographic indices were delineated for three mesoscale

  8. Digital soil mapping for the support of delineation of Areas Facing Natural Constraints defined by common European biophysical criteria

    NASA Astrophysics Data System (ADS)

    Pásztor, László; Bakacsi, Zsófia; Laborczi, Annamária; Takács, Katalin; Szatmári, Gábor; Tóth, Tibor; Szabó, József

    2016-04-01

    One of the main objectives of the EU's Common Agricultural Policy is to encourage maintaining agricultural production in Areas Facing Natural Constraints (ANC) in order to sustain agricultural production and use natural resources, in such a way to secure both stable production and income to farmers and to protect the environment. ANC assignment has both ecological and severe economical aspects. Recently the delimitation of ANCs is suggested to be carried out by using common biophysical diagnostic criteria on low soil productivity and poor climate conditions all over Europe. The criterion system was elaborated and has been repeatedly upgraded by JRC. The operational implementation is under member state competence. This process requires application of available soil databases and proper thematic and spatial inference methods. In our paper we present the inferences applied for the latest identification and delineation of areas with low soil productivity in Hungary according to JRC biophysical criteria related to soil: limited soil drainage, texture and stoniness (coarse texture, heavy clay, vertic properties), shallow rooting depth, chemical properties (salinity, sodicity, low pH). The compilation of target specific maps were based on the available legacy and recently collected data. In the present work three different data sources were used. The most relevant available data were queried from the datasets for each mapped criterion for either direct application or for the compilation a suitable, synthetic (non-measured) parameter. In some cases the values of the target variable originated from only one, in other cases from more databases. The reference dataset used in the mapping process was set up after substantial statistical analysis and filtering. It consisted of the values of the target variable attributed to the finally selected georeferenced locations. For spatial inference regression kriging was applied. Accuracy assessment was carried out by Leave One Out

  9. Combined reflectance confocal microscopy-optical coherence tomography for delineation of basal cell carcinoma margins: an ex vivo study

    PubMed Central

    Iftimia, Nicusor; Peterson, Gary; Chang, Ernest W.; Maguluri, Gopi; Fox, William; Rajadhyaksha, Milind

    2016-01-01

    Abstract. We present a combined reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) approach, integrated within a single optical layout, for diagnosis of basal cell carcinomas (BCCs) and delineation of margins. While RCM imaging detects BCC presence (diagnoses) and its lateral spreading (margins) with measured resolution of ∼1  μm, OCT imaging delineates BCC depth spreading (margins) with resolution of ∼7  μm. When delineating margins in 20 specimens of superficial and nodular BCCs, depth could be reliably determined down to ∼600  μm, and agreement with histology was within about ±50  μm. PMID:26780224

  10. Delineation of recharge areas for selected wells in the St. Peter-Prairie du Chien-Jordan Aquifer, Rochester, Minnesota

    USGS Publications Warehouse

    Delin, G.N.; Almendinger, James Edward

    1991-01-01

    Hydrogeologic mapping and numerical modeling were used to delineate zones of contribution to wells, defined as all parts of a ground-water-flow system that could supply water to a well. The zones of contribution delineated by use of numerical modeling have similar orientation (parallel to regional flow directions) but significantly different areas than the zones of contribution delineated by use of hydrogeologic mapping. Differences in computed areas of recharge are attributed to the capability of the numerical model to more accurately represent (1) the three-dimensional flow system, (2) hydrologic boundaries like streams, (3) variable recharge, and (4) the influence of nearby pumped wells, compared to the analytical models.

  11. Delineation of recharge areas for selected wells in the St. Peter-Prairie du Chien-Jordan aquifer, Rochester, Minnesota

    USGS Publications Warehouse

    Delin, G.N.; Almendinger, James Edward

    1993-01-01

    Hydrogeologic mapping and numerical modeling were used to delineate zones of contribution to wells, defined as all parts of a ground-water-flow system that could supply water to a well. The zones of contribution delineated by use of numerical modeling have similar orientation (parallel to regional flow directions) but significantly different areas than the zones of contribution delineated by use of hydrogeologic mapping. Differences in computed areas of recharge are attributed to the capability of the numerical model to more accurately represent (1) the three-dimensional flow system, (2) hydrologic boundaries such as streams, (3) variable recharge, and (4) the influence of nearby pumped wells, compared to the analytical models.

  12. Combined reflectance confocal microscopy-optical coherence tomography for delineation of basal cell carcinoma margins: an ex vivo study

    NASA Astrophysics Data System (ADS)

    Iftimia, Nicusor; Peterson, Gary; Chang, Ernest W.; Maguluri, Gopi; Fox, William; Rajadhyaksha, Milind

    2016-01-01

    We present a combined reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) approach, integrated within a single optical layout, for diagnosis of basal cell carcinomas (BCCs) and delineation of margins. While RCM imaging detects BCC presence (diagnoses) and its lateral spreading (margins) with measured resolution of ˜1 μm, OCT imaging delineates BCC depth spreading (margins) with resolution of ˜7 μm. When delineating margins in 20 specimens of superficial and nodular BCCs, depth could be reliably determined down to ˜600 μm, and agreement with histology was within about ±50 μm.

  13. Calculation of a water budget and delineation of contributing sources to drainflows in the western San Joaquin Valley, California

    USGS Publications Warehouse

    Fio, John L.

    1994-01-01

    Geohydrologic data and a ground-water flow model were used to calculate a water budget and evaluate the contribution of regional ground-water flow to on-farm drainflow in a part of the western San Joaquin Valley, California. Regional ground-water flow is affected by the distribution of unconsoli- dated coarse- and fine- grained sediment. Predomi- nantly coarse-grained sediment in the upslope areas results in a water table more than 3 meters below land surface, but the low-lying areas are underlain by predominantly fine-grained sediments and have a water table within 3 meters of land surface. The vertical component of flow is downward in the upslope areas, but upward at some locations in the low-lying areas. Model simulation results indicate that about 89 percent of the drainflow (18.5 times 10(6) cubic meters per year) originates as recharge within the fields that overlie the drainage systems, and 11 percent of the drainflow (2.3 times 10(6) cubic meters per year) is lateral-flowing ground water and upward deept percolation originating as recharge at fields upslope from the drainage systems. The lateral-flow and upward deep perco- lation can move substantial distances (as great as 3.6 kilometers horizontally and from depths greater than 29 meters below land surface), and require from 10 to more than 90 years to reach the drainage systems. (USGS)

  14. Cone-Beam CT-Based Delineation of Stereotactic Lung Targets: The Influence of Image Modality and Target Size on Interobserver Variability

    SciTech Connect

    Altorjai, Gabriela

    2012-02-01

    Purpose: It is generally agreed that the safe implementation of stereotactic body radiotherapy requires image guidance. The aim of this work was to assess interobserver variability in the delineation of lung lesions on cone-beam CT (CBCT) images compared with CT-based contouring for adaptive stereotactic body radiotherapy. The influence of target size was also evaluated. Methods and Materials: Eight radiation oncologists delineated gross tumor volumes in 12 patient cases (non-small cell lung cancer I-II or solitary metastasis) on planning CTs and on CBCTs. Cases were divided into two groups with tumor diameters of less than (Group A) or more than 2 cm (Group B). Comparison of mean volumes delineated by all observers and range and coefficient of variation were reported for each case and image modality. Interobserver variability was assessed by means of standard error of measurement, conformity index (CI), and its generalized observer-independent approach. The variance between single observers on CT and CBCT images was measured via interobserver reliability coefficient. Results: Interobserver variability on CT images was 17% with 0.79 reliability, compared with 21% variability on CBCT and 0.76 reliability. On both image modalities, values of the intraobserver reliability coefficient (0.99 for CT and 0.97 for CBCT) indicated high reproducibility of results. In general, lower interobserver agreement was observed for small lesions (CI{sub genA} = 0.62 {+-} 0.06 vs. CI{sub genB} = 0.70 {+-} 0.03, p < 0.05). The analysis of single patient cases revealed that presence of spicules, diffuse infiltrations, proximity of the tumors to the vessels and thoracic wall, and respiration motion artifacts presented the main sources of the variability. Conclusion: Interobserver variability for Stage I-II non-small cell lung cancer and lung metastasis was slightly higher on CBCT compared with CT. Absence of significant differences in interobserver variability suggests that CBCT imaging

  15. Use of a ground-water flow model to delineate contributing areas to the Puchack Well Field, Pennsauken township and vicinity, Camden county, New Jersey

    USGS Publications Warehouse

    Pope, Daryll A.; Watt, Martha K.

    2005-01-01

    Middle and Lower aquifers. Simulated water-level differences across the confining units at most of the nested wells were within ? 0.5 feet of the differences calculated from measured water levels. The existing flow model was modified to meet NJDEP guidelines for delineating contributing areas in complex hydrogeologic settings. These modifications included rediscretizing the model grid to a finer grid and preparing the water-use data set for use in the rediscretized model. The contributing area to the Puchack well field was delineated by means of particle tracking. An uncertainty analysis was conducted in which 36 model-input parameters were both increased and decreased until the resulting change in simulated heads exceeded the model-calibration criterion of ? 5 feet at any model cell. Porosity most affected the size and shape of the contributing area. The distribution of withdrawals at the Morris/Delair well field and variations in recharge affected both the size and shape of contributing area to the Puchack well field and the source of water to the Puchack wells. The results of the uncertainty analysis were combined to determine the 'aggregate' contributing area to the Puchack well field--a composite of areas on the land surface that contributed flow to the Puchack well field in less than 12 years in any uncertainty simulation. The shape of the aggregate contributing area was most similar to that associated with a reduction in porosity, which indirectly affected the size and shape of the contributing areas by changing travel time.

  16. Delineation of Nested Wetland Catchments and Modeling of Hydrologic Connectivity Using LiDAR Data and Aerial Imagery

    EPA Science Inventory

    In traditional watershed delineation and topographic modelling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In r...

  17. Charting the Visual Space of Insect Eyes - Delineating the Guidance, Navigation and Control of Insect Flight by Their Optical Sensor

    DTIC Science & Technology

    2014-06-01

    AFRL-AFOSR-UK-TR-2014-0021 Charting the visual space of insect eyes - Delineating the guidance, navigation and control of insect ...the visual space of insect eyes - Delineating the guidance, navigation and control of insect flight by their optical sensor 5a. CONTRACT NUMBER...is unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Insect visual systems are extremely compact and presumably optimized for optimal

  18. Delineation of the Pahute Mesa–Oasis Valley groundwater basin, Nevada

    USGS Publications Warehouse

    Fenelon, Joseph M.; Halford, Keith J.; Moreo, Michael T.

    2016-01-22

    This report delineates the Pahute Mesa–Oasis Valley (PMOV) groundwater basin, where recharge occurs, moves downgradient, and discharges to Oasis Valley, Nevada. About 5,900 acre-feet of water discharges annually from Oasis Valley, an area of springs and seeps near the town of Beatty in southern Nevada. Radionuclides in groundwater beneath Pahute Mesa, an area of historical underground nuclear testing at the Nevada National Security Site, are believed to be migrating toward Oasis Valley. Delineating the boundary of the PMOV groundwater basin is necessary to adequately assess the potential for transport of radionuclides from Pahute Mesa to Oasis Valley.The PMOV contributing area is defined based on regional water-level contours, geologic controls, and knowledge of adjacent flow systems. The viability of this area as the contributing area to Oasis Valley and the absence of significant interbasin flow between the PMOV groundwater basin and adjacent basins are shown regionally and locally. Regional constraints on the location of the contributing area boundary and on the absence of interbasin groundwater flow are shown by balancing groundwater discharges in the PMOV groundwater basin and adjacent basins against available water from precipitation. Internal consistency for the delineated contributing area is shown by matching measured water levels, groundwater discharges, and transmissivities with simulated results from a single-layer, steady-state, groundwater-flow model. An alternative basin boundary extending farther north than the final boundary was rejected based on a poor chloride mass balance and a large imbalance in the northern area between preferred and simulated recharge.

  19. Accuracy Assessment of Crown Delineation Methods for the Individual Trees Using LIDAR Data

    NASA Astrophysics Data System (ADS)

    Chang, K. T.; Lin, C.; Lin, Y. C.; Liu, J. K.

    2016-06-01

    Forest canopy density and height are used as variables in a number of environmental applications, including the estimation of biomass, forest extent and condition, and biodiversity. The airborne Light Detection and Ranging (LiDAR) is very useful to estimate forest canopy parameters according to the generated canopy height models (CHMs). The purpose of this work is to introduce an algorithm to delineate crown parameters, e.g. tree height and crown radii based on the generated rasterized CHMs. And accuracy assessment for the extraction of volumetric parameters of a single tree is also performed via manual measurement using corresponding aerial photo pairs. A LiDAR dataset of a golf course acquired by Leica ALS70-HP is used in this study. Two algorithms, i.e. a traditional one with the subtraction of a digital elevation model (DEM) from a digital surface model (DSM), and a pit-free approach are conducted to generate the CHMs firstly. Then two algorithms, a multilevel morphological active-contour (MMAC) and a variable window filter (VWF), are implemented and used in this study for individual tree delineation. Finally, experimental results of two automatic estimation methods for individual trees can be evaluated with manually measured stand-level parameters, i.e. tree height and crown diameter. The resulting CHM generated by a simple subtraction is full of empty pixels (called "pits") that will give vital impact on subsequent analysis for individual tree delineation. The experimental results indicated that if more individual trees can be extracted, tree crown shape will became more completely in the CHM data after the pit-free process.

  20. Comparison of Eh and H2 measurements for delineating redox processes in a contaminated aquifer

    USGS Publications Warehouse

    Chapelle, Francis H.; Haack, Sheridan K.; Adriaens, Peter; Henry, Mark A.; Bradley, Paul M.

    1996-01-01

    Measurements of oxidation−reduction potential (Eh) and concentrations of dissolved hydrogen (H2) were made in a shallow groundwater system contaminated with solvents and jet fuel to delineate the zonation of redox processes. Eh measurements ranged from +69 to −158 mV in a cross section of the contaminated plume and accurately delineated oxic from anoxic groundwater. Plotting measured Eh and pH values on an equilibrium stability diagram indicated that Fe(III) reduction was the predominant redox process in the anoxic zone and did not indicate the presence of methanogenesis and sulfate reduction. In contrast, measurements of H2concentrations indicated that methanogenesis predominated in heavily contaminated sediments near the water table surface (H2 ∼ 7.0 nM) and that the methanogenic zone was surrounded by distinct sulfate-reducing (H2 ∼ 1−4 nM) and Fe(III)-reducing (H2 ∼ 0.1−0.8 nM) zones. The presence of methanogenesis, sulfate reduction, and Fe(III) reduction was confirmed by the distribution of dissolved oxygen, sulfate, Fe(II), and methane in groundwater. These results show that H2 concentrations were more useful for identifying anoxic redox processes than Ehmeasurements in this groundwater system. However, H2-based redox zone delineations are more reliable when H2 concentrations are interpreted in the context of electron-acceptor (oxygen, nitrate, sulfate) availability and the presence of final products [Fe(II), sulfide, methane] of microbial metabolism.

  1. Comparison of Eh and H2 measurements for delineating redox zones in a contaminated aquifer

    USGS Publications Warehouse

    Chapelle, Francis H.; Haack, Sheridan K.; Adriaens, Peter; Henry, Mark A.; Bradley, Paul M.

    1996-01-01

    Measurements of oxidation−reduction potential (Eh) and concentrations of dissolved hydrogen (H2) were made in a shallow groundwater system contaminated with solvents and jet fuel to delineate the zonation of redox processes. Eh measurements ranged from +69 to −158 mV in a cross section of the contaminated plume and accurately delineated oxic from anoxic groundwater. Plotting measured Eh and pH values on an equilibrium stability diagram indicated that Fe(III) reduction was the predominant redox process in the anoxic zone and did not indicate the presence of methanogenesis and sulfate reduction. In contrast, measurements of H2concentrations indicated that methanogenesis predominated in heavily contaminated sediments near the water table surface (H2 ∼ 7.0 nM) and that the methanogenic zone was surrounded by distinct sulfate-reducing (H2 ∼ 1−4 nM) and Fe(III)-reducing (H2 ∼ 0.1−0.8 nM) zones. The presence of methanogenesis, sulfate reduction, and Fe(III) reduction was confirmed by the distribution of dissolved oxygen, sulfate, Fe(II), and methane in groundwater. These results show that H2 concentrations were more useful for identifying anoxic redox processes than Ehmeasurements in this groundwater system. However, H2-based redox zone delineations are more reliable when H2 concentrations are interpreted in the context of electron-acceptor (oxygen, nitrate, sulfate) availability and the presence of final products [Fe(II), sulfide, methane] of microbial metabolism.

  2. Evaluation of Peritumoral Edema in the Delineation of Radiotherapy Clinical Target Volumes for Glioblastoma

    SciTech Connect

    Chang, Eric L. . E-mail: echang@mdanderson.org; Akyurek, Serap; Avalos, Tedde C; Rebueno, Neal C; Spicer, Chris C; Garcia, John C; Famiglietti, Robin; Allen, Pamela K.; Chao, K.S. Clifford; Mahajan, Anita; Woo, Shiao Y.; Maor, Moshe H.

    2007-05-01

    Purpose: To evaluate the spatial relationship between peritumoral edema and recurrence pattern in patients with glioblastoma (GBM). Methods and Materials: Forty-eight primary GBM patients received three-dimensional conformal radiotherapy that did not intentionally include peritumoral edema within the clinical target volume between July 2000 and June 2001. All 48 patients have subsequently recurred, and their original treatment planning parameters were used for this study. New theoretical radiation treatment plans were created for the same 48 patients, based on Radiation Therapy Oncology Group (RTOG) target delineation guidelines that specify inclusion of peritumoral edema. Target volume and recurrent tumor coverage, as well as percent volume of normal brain irradiated, were assessed for both methods of target delineation using dose-volume histograms. Results: A comparison between the location of recurrent tumor and peritumoral edema volumes from all 48 cases failed to show correlation by linear regression modeling (r {sup 2} 0.0007; p = 0.3). For patients with edema >75 cm{sup 3}, the percent volume of brain irradiated to 46 Gy was significantly greater in treatment plans that intentionally included peritumoral edema compared with those that did not (38% vs. 31%; p = 0.003). The pattern of failure was identical between the two sets of plans (40 central, 3 in-field, 3 marginal, and 2 distant recurrence). Conclusion: Clinical target volume delineation based on a 2-cm margin rather than on peritumoral edema did not seem to alter the central pattern of failure for patients with GBM. For patients with peritumoral edema >75 cm{sup 3}, using a constant 2-cm margin resulted in a smaller median percent volume of brain being irradiated to 30 Gy, 46 Gy, and 50 Gy compared with corresponding theoretical RTOG plans that deliberately included peritumoral edema.

  3. Automated delineation of radiotherapy volumes: are we going in the right direction?

    PubMed Central

    Whitfield, G A; Price, P; Price, G J; Moore, C J

    2013-01-01

    ABSTRACT. Rapid and accurate delineation of target volumes and multiple organs at risk, within the enduring International Commission on Radiation Units and Measurement framework, is now hugely important in radiotherapy, owing to the rapid proliferation of intensity-modulated radiotherapy and the advent of four-dimensional image-guided adaption. Nevertheless, delineation is still generally clinically performed with little if any machine assistance, even though it is both time-consuming and prone to interobserver variation. Currently available segmentation tools include those based on image greyscale interrogation, statistical shape modelling and body atlas-based methods. However, all too often these are not able to match the accuracy of the expert clinician, which remains the universally acknowledged gold standard. In this article we suggest that current methods are fundamentally limited by their lack of ability to incorporate essential human clinical decision-making into the underlying models. Hybrid techniques that utilise prior knowledge, make sophisticated use of greyscale information and allow clinical expertise to be integrated are needed. This may require a change in focus from automated segmentation to machine-assisted delineation. Similarly, new metrics of image quality reflecting fitness for purpose would be extremely valuable. We conclude that methods need to be developed to take account of the clinician's expertise and honed visual processing capabilities as much as the underlying, clinically meaningful information content of the image data being interrogated. We illustrate our observations and suggestions through our own experiences with two software tools developed as part of research council-funded projects. PMID:23239689

  4. Inter- and intra-observer variations in the delineation of lesions in mammograms

    NASA Astrophysics Data System (ADS)

    Buelow, Thomas; Heese, Harald S.; Grewer, Ruediger; Kutra, Dominik; Wiemker, Rafael

    2015-03-01

    Many clinical and research tasks require the delineation of lesions in radiological images. There is a variety of methods available for deriving such delineations, ranging from free hand manual contouring and manual positioning of lowparameter graphical objects, to (semi-)automatic computerized segmentation methods. In this paper we investigate the impact of the chosen segmentation method on the inter-observer variability of the resulting contour. Three different methods are compared in this paper, namely (1) manual positioning of an ellipse, (2) an automatic segmentation method, coined live-segmentation, which depends on the current mouse pointer position as input information and is updated in real-time as the user hovers with the mouse over the image and (3) free form segmentation which is realized by allowing the user to pull the result of method (2) to image positions that the contour is required to pass. Each of the three methods was used by three experienced radiologists to delineate a set of 215 round breast lesion images in digital mammograms. Agreement between contours was assessed by computing the Dice coefficient. The median Dice coefficient for the ellipses placed by different readers was 0.85. The intra-reader Dice coefficient comparing ellipses and livesegmentations was 0.84, thus showing that the live-segmentation results agree with ellipse segmentations to the same extent as readers agree on the ellipse placement. Inter-observer agreement when using the live-segmentation was higher than for the ellipses (median Dice = 0.91 vs. 0.85) showing that the live-segmentation is a more reproducible alternative to the ellipse placement.

  5. Spatial and thematic assessment of object-based forest stand delineation using an OFA-matrix

    NASA Astrophysics Data System (ADS)

    Hernando, A.; Tiede, D.; Albrecht, F.; Lang, S.

    2012-10-01

    The delineation and classification of forest stands is a crucial aspect of forest management. Object-based image analysis (OBIA) can be used to produce detailed maps of forest stands from either orthophotos or very high resolution satellite imagery. However, measures are then required for evaluating and quantifying both the spatial and thematic accuracy of the OBIA output. In this paper we present an approach for delineating forest stands and a new Object Fate Analysis (OFA) matrix for accuracy assessment. A two-level object-based orthophoto analysis was first carried out to delineate stands on the Dehesa Boyal public land in central Spain (Avila Province). Two structural features were first created for use in class modelling, enabling good differentiation between stands: a relational tree cover cluster feature, and an arithmetic ratio shadow/tree feature. We then extended the OFA comparison approach with an OFA-matrix to enable concurrent validation of thematic and spatial accuracies. Its diagonal shows the proportion of spatial and thematic coincidence between a reference data and the corresponding classification. New parameters for Spatial Thematic Loyalty (STL), Spatial Thematic Loyalty Overall (STLOVERALL) and Maximal Interfering Object (MIO) are introduced to summarise the OFA-matrix accuracy assessment. A stands map generated by OBIA (classification data) was compared with a map of the same area produced from photo interpretation and field data (reference data). In our example the OFA-matrix results indicate good spatial and thematic accuracies (>65%) for all stand classes except for the shrub stands (31.8%), and a good STLOVERALL (69.8%). The OFA-matrix has therefore been shown to be a valid tool for OBIA accuracy assessment.

  6. On using simple time-of-travel capture zone delineation methods.

    PubMed

    Ceric, Admir; Haitjema, Henk

    2005-01-01

    As part of its Wellhead Protection Program, the U.S. EPA mandates the delineation of "time-of-travel capture zones" as the basis for the definition of wellhead protection zones surrounding drinking water production wells. Depending on circumstances the capture zones may be determined using methods that range from simply drawing a circle around the well to sophisticated ground water flow and transport modeling. The simpler methods are attractive when faced with the delineation of hundreds or thousands of capture zones for small public drinking water supply wells. On the other hand, a circular capture zone may not be adequate in the presence of an ambient ground water flow regime. A dimensionless time-of-travel parameter T is used to determine when calculated fixed-radius capture zones can be used for drinking water production wells. The parameter incorporates aquifer properties, the magnitude of the ambient ground water flow field, and the travel time criterion for the time-of-travel capture zone. In the absence of interfering flow features, three different simple capture zones can be used depending on the value of T . A modified calculated fixed-radius capture zone proves protective when T < 0.1, while a more elongated capture zone must be used when T > 1. For values of T between 0.1 and 1, a circular capture zone can be used that is eccentric with respect to the well. Finally, calculating T allows for a quick assessment of the validity of circular capture zones without redoing the delineation with a computer model.

  7. Techniques of Fluorescence Cholangiography During Laparoscopic Cholecystectomy for Better Delineation of the Bile Duct Anatomy

    PubMed Central

    Kono, Yoshiharu; Ishizawa, Takeaki; Tani, Keigo; Harada, Nobuhiro; Kaneko, Junichi; Saiura, Akio; Bandai, Yasutsugu; Kokudo, Norihiro

    2015-01-01

    Abstract To evaluate the clinical and technical factors affecting the ability of fluorescence cholangiography (FC) using indocyanine green (ICG) to delineate the bile duct anatomy during laparoscopic cholecystectomy (LC). Application of FC during LC began after laparoscopic fluorescence imaging systems became commercially available. In 108 patients undergoing LC, FC was performed by preoperative intravenous injection of ICG (2.5 mg) during dissection of Calot's triangle, and clinical factors affecting the ability of FC to delineate the extrahepatic bile ducts were evaluated. Equipment-related factors associated with bile duct detectability were also assessed among 5 laparoscopic systems and 1 open fluorescence imaging system in ex vivo studies. FC delineated the confluence between the cystic duct and common hepatic duct (CyD–CHD) before and after dissection of Calot's triangle in 80 patients (74%) and 99 patients (92%), respectively. The interval between ICG injection and FC before dissection of Calot's triangle was significantly longer in the 80 patients in whom the CyD–CHD confluence was detected by fluorescence imaging before dissection (median, 90 min; range, 15–165 min) than in the remaining 28 patients in whom the confluence was undetectable (median, 47 min; range, 21–205 min; P < 0.01). The signal contrast on the fluorescence images of the bile duct samples was significantly different among the laparoscopic imaging systems and tended to decrease more steeply than those of the open imaging system as the target-laparoscope distance increased and porcine tissues covering the samples became thicker. FC is a simple navigation tool for obtaining a biliary roadmap to reach the “critical view of safety” during LC. Key factors for better bile duct identification by FC are administration of ICG as far in advance as possible before surgery, sufficient extension of connective tissues around the bile ducts, and placement of the tip of

  8. Delineation of the Troy Bedrock Valley and particle-tracking analysis of ground-water flow underlying Belvidere, Illinois

    USGS Publications Warehouse

    Mills, Patrick C.; Halford, Keith J.; Cobb, R.P.

    2002-01-01

    The U.S. Geological Survey, U.S. Environmental Protection Agency, and Illinois Environmental Protection Agency began a study of the hydrogeology, flow system, and distribution of contaminants in the aquifers underlying Belvidere, Ill., and vicinity in 1992. As part of the study, the ancestral Troy Bedrock Valley, located about 1.5 miles west of Belvidere, was identified as an important part of the ground-water-flow system. In the deepest parts of the valley, the basal Glenwood confining unit may be absent; thick deposits of sand and gravel that infill part of the valley may directly overlie the sandstone St. Peter aquifer, a regionally important source of water for public supply. With few deep wells open to the St. Peter aquifer present in the valley to provide necessary geologic information, tritium and other water-chemistry data were collected from eight wells to possibly delineate areas where the confining unit may be absent; the data also provide baseline water-quality information for an area expecting changes in land use and increases in water withdrawal. Also as part of the study, particle-tracking analysis was done using an available flow model to (1) identify possible discharge locations of ground water and contaminants and (2) delineate areas contributing recharge to the Belvidere municipal wells. This report presents and interprets water-chemistry data collected during December 2000 and presents results of particle-tracking analysis. Ground water in samples from two of four wells open to the St. Peter aquifer appears to have recharged after 1954, suggesting that the Glenwood confining unit may be absent near the wells. Other hydrogeologic and water-chemistry data, however, were inconclusive or contradictory. Concentrations of iron, manganese, and lead exceeded maximum contaminant levels in five or less samples, but materials associated with the water-distribution systems appear to contribute to the elevated concentrations above natural levels. Particle

  9. 46, XY, del (3) (pter-->p25) syndrome: further delineation of the clinical phenotype.

    PubMed

    Benini, D; Vino, L; Vecchini, S; Fanos, V

    1999-12-01

    A boy with monosomy for the distal part of the short arm of chromosome 3 is described. The clinical features this patient has in common with the previously reported cases include pre- and post-natal growth delay, microcephaly, craniofacial dysmorphism and mental retardation. In addition, minor abnormalities not previously reported were observed, such as snapping thumbs, dorsiflected big toes, connecting anterior and posterior fontanelles at birth, nasolacrimal duct stenosis and double urethral meatus. Conclusion These five new clinical findings may help in further delineation of the syndrome and allow its early recognition. A complete revision of clinical findings published in literature is reported.

  10. Automated volume of interest delineation and rendering of cone beam CT images in interventional cardiology

    NASA Astrophysics Data System (ADS)

    Lorenz, Cristian; Schäfer, Dirk; Eshuis, Peter; Carroll, John; Grass, Michael

    2012-02-01

    Interventional C-arm systems allow the efficient acquisition of 3D cone beam CT images. They can be used for intervention planning, navigation, and outcome assessment. We present a fast and completely automated volume of interest (VOI) delineation for cardiac interventions, covering the whole visceral cavity including mediastinum and lungs but leaving out rib-cage and spine. The problem is addressed in a model based approach. The procedure has been evaluated on 22 patient cases and achieves an average surface error below 2mm. The method is able to cope with varying image intensities, varying truncations due to the limited reconstruction volume, and partially with heavy metal and motion artifacts.

  11. Simple diagrammatic method to delineate male urethra in prostate cancer radiotherapy: an MRI based approach.

    PubMed

    Kataria, Tejinder; Gupta, Deepak; Goyal, Shikha; Bisht, Shyam S; Chaudhary, Ravi; Narang, Kushal; Banerjee, Susovan; Basu, Trinanjan; Abhishek, Ashu; Sambasivam, Sasikumar; Vishnu, Nisha T

    2016-12-01

    Stereotactic body radiotherapy (SBRT) is being increasingly utilized in the treatment of prostate cancer. With the advent of high-precision radiosurgery systems, it is possible to obtain dose distributions akin to high-dose rate brachytherapy with SBRT. However, urethral toxicity has a significant impact on the quality of life in patients with prostate cancer. Contouring the male urethra on a CT scan is difficult in the absence of an indwelling catheter. In this pictorial essay, we have used the MRI obtained for radiotherapy planning to aid in the delineation of the male urethra and have attempted to define guidelines for the same.

  12. [Metabolically active volumes automatic delineation methodologies in PET imaging: review and perspectives].

    PubMed

    Hatt, M; Boussion, N; Cheze-Le Rest, C; Visvikis, D; Pradier, O

    2012-02-01

    PET imaging is now considered a gold standard tool in clinical oncology, especially for diagnosis purposes. More recent applications such as therapy follow-up or tumor targeting in radiotherapy require a fast, accurate and robust metabolically active tumor volumes delineation on emission images, which cannot be obtained through manual contouring. This clinical need has sprung a large number of methodological developments regarding automatic methods to define tumor volumes on PET images. This paper reviews most of the methodologies that have been recently proposed and discusses their framework and methodological and/or clinical validation. Perspectives regarding the future work to be done are also suggested.

  13. Dosimetric Consequences of Interobserver Variability in Delineating the Organs at Risk in Gynecologic Interstitial Brachytherapy

    PubMed Central

    Damato, Antonio L.; Townamchai, Kanopkis; Albert, Michele; Bair, Ryan J.; Cormack, Robert A.; Jang, Joanne; Kovacs, Arpad; Lee, Larissa J.; Mak, Kimberley S.; Mirabeau-Beale, Kristina L.; Mouw, Kent W.; Phillips, John G.; Pretz, Jennifer L.; Russo, Andrea L.; Lewis, John H.; Viswanathan, Akila N.

    2014-01-01

    Purpose To investigate the dosimetric variability associated with interobserver organ-at-risk delineation differences on computed tomography in patients undergoing gynecologic interstitial brachytherapy. Methods and Materials The rectum, bladder and sigmoid of 14 patients treated with gynecologic interstitial brachytherapy were retrospectively contoured by 13 physicians. Geometric variability was calculated using κ statistics, conformity index (CIgen), and coefficient of variation (CV) of volumes contoured across physicians. Dosimetric variability of the single-fraction D0.1cc and D2cc was assessed through CV across physicians, and the standard deviation of the total EQD2 (equivalent dose in 2 Gy per fraction) brachytherapy dose (SDTOT) was calculated. Results The population mean ± 1 standard deviation of κ, CIgen and volume CV were, respectively: 0.77 ± 0.06, 0.70 ± 0.08 and 20% ± 6% for bladder; 0.74 ± 06, 0.67 ± 0.08 and 20% ± 5% for rectum, and 0.33 ± 0.20, 0.26 ± 0.17 and 82% ± 42% for sigmoid. Dosimetric variability was: for bladder, CV = 31% ± 19% (SDTOT = 72 ± 64 Gy) for D0.1cc and CV = 16% + 10% (SDTOT = 9 ± 6 Gy) for D2cc; for rectum, CV = 11% ± 5% (SDTOT = 16 ± 17 Gy) for D0.1cc and CV = 7% ± 2% (SDTOT = 4 ± 3 Gy) for D2cc; for sigmoid, CV = 39% ± 28% (SDTOT = 12 ± 18 Gy) for D0.1cc and CV = 34% ± 19% (SDTOT = 4 ± 4 Gy) for D2cc. Conclusions Delineation of bladder and rectum by 13 physicians demonstrated substantial geometric agreement and resulted in good dosimetric agreement for all dose-volume histogram parameters except bladder D0.1cc. Small delineation differences in high-dose regions by the posterior bladder wall may explain these results. The delineation of sigmoid showed fair geometric agreement. The higher dosimetric variability for sigmoid compared with rectum and bladder did not correlate with higher variability in the total brachytherapy dose but rather may be due to the sigmoid being positioned in low-dose regions in

  14. Dosimetric Consequences of Interobserver Variability in Delineating the Organs at Risk in Gynecologic Interstitial Brachytherapy

    SciTech Connect

    Damato, Antonio L.; Bair, Ryan J.; Cormack, Robert A.; Kovacs, Arpad; Lee, Larissa J.; Lewis, John H.; Viswanathan, Akila N.

    2014-07-01

    Purpose: To investigate the dosimetric variability associated with interobserver organ-at-risk delineation differences on computed tomography in patients undergoing gynecologic interstitial brachytherapy. Methods and Materials: The rectum, bladder, and sigmoid of 14 patients treated with gynecologic interstitial brachytherapy were retrospectively contoured by 13 physicians. Geometric variability was calculated using κ statistics, conformity index (CI{sub gen}), and coefficient of variation (CV) of volumes contoured across physicians. Dosimetric variability of the single-fraction D{sub 0.1cc} and D{sub 2cc} was assessed through CV across physicians, and the standard deviation of the total EQD2 (equivalent dose in 2 Gy per fraction) brachytherapy dose (SD{sup TOT}) was calculated. Results: The population mean ± 1 standard deviation of κ, CI{sub gen}, and volume CV were, respectively: 0.77 ± 0.06, 0.70 ± 0.08, and 20% ± 6% for bladder; 0.74 ± 06, 0.67 ± 0.08, and 20% ± 5% for rectum; and 0.33 ± 0.20, 0.26 ± 0.17, and 82% ± 42% for sigmoid. Dosimetric variability was as follows: for bladder, CV = 31% ± 19% (SD{sup TOT} = 72 ± 64 Gy) for D{sub 0.1cc} and CV = 16% ± 10% (SD{sup TOT} = 9 ± 6 Gy) for D{sub 2cc}; for rectum, CV = 11% ± 5% (SD{sup TOT} = 16 ± 17 Gy) for D{sub 0.1cc} and CV = 7% ± 2% (SD{sup TOT} = 4 ± 3 Gy) for D{sub 2cc}; for sigmoid, CV = 39% ± 28% (SD{sup TOT} = 12 ± 18 Gy) for D{sub 0.1cc} and CV = 34% ± 19% (SD{sup TOT} = 4 ± 4 Gy) for D{sub 2cc.} Conclusions: Delineation of bladder and rectum by 13 physicians demonstrated substantial geometric agreement and resulted in good dosimetric agreement for all dose-volume histogram parameters except bladder D{sub 0.1cc.} Small delineation differences in high-dose regions by the posterior bladder wall may explain these results. The delineation of sigmoid showed fair geometric agreement. The higher dosimetric variability for sigmoid compared with rectum and bladder did not correlate with

  15. INEEL Source Water Assessment

    SciTech Connect

    Sehlke, Gerald

    2003-03-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) covers approximately 890 mi2 and includes 12 public water systems that must be evaluated for Source water protection purposes under the Safe Drinking Water Act. Because of its size and location, six watersheds and five aquifers could potentially affect the INEEL’s drinking water sources. Based on a preliminary evaluation of the available information, it was determined that the Big Lost River, Birch Creek, and Little Lost River Watersheds and the eastern Snake River Plain Aquifer needed to be assessed. These watersheds were delineated using the United States Geologic Survey’s Hydrological Unit scheme. Well capture zones were originally estimated using the RESSQC module of the Environmental Protection Agency’s Well Head Protection Area model, and the initial modeling assumptions and results were checked by running several scenarios using Modflow modeling. After a technical review, the resulting capture zones were expanded to account for the uncertainties associated with changing groundwater flow directions, a thick vadose zone, and other data uncertainties. Finally, all well capture zones at a given facility were merged to a single wellhead protection area at each facility. A contaminant source inventory was conducted, and the results were integrated with the well capture zones, watershed and aquifer information, and facility information using geographic information system technology to complete the INEEL’s Source Water Assessment. Of the INEEL’s 12 public water systems, three systems rated as low susceptibility (EBR-I, Main Gate, and Gun Range), and the remainder rated as moderate susceptibility. No INEEL public water system rated as high susceptibility. We are using this information to develop a source water management plan from which we will subsequently implement an INEEL-wide source water management program. The results are a very robust set of wellhead protection areas that will

  16. Interobserver variation in cervical cancer tumor delineation for image-based radiotherapy planning among and within different specialties.

    PubMed

    Wu, Dee H; Mayr, Nina A; Karatas, Yasemin; Karatas, Rifat; Adli, Mustafa; Edwards, Susan M; Wolff, James D; Movahed, Allen; Montebello, Joseph F; Yuh, William T C

    2005-01-01

    Radiation therapy for cervical cancer involves a team of specialists, including diagnostic radiologists (DRs), radiation oncologists (ROs), and medical physicists (MPs), to optimize imaging-based radiation therapy planning. The purpose of the study was to investigate the interobserver variations in tumor delineation on MR images of cervical cancer within the same and among different specialties. Twenty MRI cervical cancer studies were independently reviewed by two DRs, two ROs, and two MPs. For every study, each specialist contoured the tumor regions of interest (ROIs) on T2-weighted Turbo Spin Echo sagittal images on all slices containing tumor, and the total tumor volume was computed for statistical analysis. Analysis of variance (ANOVA) was used to compare the differences in tumor volume delineation among the observers. A graph of all tumor-delineated volumes was generated, and differences between the maximum and minimum volumes over all the readers for each patient dataset were computed. Challenges during the evaluation process for tumor delineation were recorded for each specialist. Interobserver variations of delineated tumor volumes were significant (p < 0.01) among all observers based on a repeated measures ANOVA, which produced an F(5,95) = 3.55. The median difference between the maximum delineated volume and minimum delineated volume was 33.5 cm3 (which can be approximated by a sphere of 4.0 cm diameter) across all 20 patients. Challenges noted for tumor delineation included the following: (1) partial voluming by parametrial fat at the periphery of the uterus; (2) extension of the tumor into parametrial space; (3) similar signal intensity of structures proximal to the tumor such as ovaries, muscles, bladder wall, bowel loops, and pubic symphysis; (4) postradiation changes such as heterogeneity and necrosis; (5) susceptibility artifacts from bowels and vaginal tampons; (6) presence of other pathologies such as atypical myoma; (7) factors that affect pelvic

  17. Mapping of monthly soil erosion risk of mainland Mauritius and its aggregation with delineated basins

    NASA Astrophysics Data System (ADS)

    Nigel, Rody; Rughooputh, Soonil

    2010-01-01

    This paper reports the mapping of monthly soil erosion risk on Mauritius which was carried out using GIS, decision rules and readily available data namely, monthly rainfall depth, soil types, slope and land cover. Slope and soil were first combined to produce soil erosion susceptibility followed by land cover to produce erosion sensitivity, and then rainfall to produce erosion risk. The high erosion areas of the Island have been extracted from the soil erosion risk maps, whereby these areas can face land degradation problems and can be responsible for sediment discharge into wetlands located at the outlet of drainage basins. As such, drainage basins have been delineated using automatic catchment delineation tools and their percentage of high erosion areas computed. Basins with the greatest percentage of high erosion areas and particularly those that directly have a wetland at the outlet can be given priority for soil and water conservation efforts. The mapping reported in this paper can be adapted to other countries which need an erosion assessment for the identification of high erosion areas and priority action areas.

  18. Ground truth delineation for medical image segmentation based on Local Consistency and Distribution Map analysis.

    PubMed

    Cheng, Irene; Sun, Xinyao; Alsufyani, Noura; Xiong, Zhihui; Major, Paul; Basu, Anup

    2015-01-01

    Computer-aided detection (CAD) systems are being increasingly deployed for medical applications in recent years with the goal to speed up tedious tasks and improve precision. Among others, segmentation is an important component in CAD systems as a preprocessing step to help recognize patterns in medical images. In order to assess the accuracy of a CAD segmentation algorithm, comparison with ground truth data is necessary. To-date, ground truth delineation relies mainly on contours that are either manually defined by clinical experts or automatically generated by software. In this paper, we propose a systematic ground truth delineation method based on a Local Consistency Set Analysis approach, which can be used to establish an accurate ground truth representation, or if ground truth is available, to assess the accuracy of a CAD generated segmentation algorithm. We validate our computational model using medical data. Experimental results demonstrate the robustness of our approach. In contrast to current methods, our model also provides consistency information at distributed boundary pixel level, and thus is invariant to global compensation error.

  19. Delineation of capture zones for municipal wells in fractured dolomite, Sturgeon Bay, Wisconsin, USA

    NASA Astrophysics Data System (ADS)

    Rayne, Todd W.; Bradbury, Kenneth R.; Muldoon, Maureen A.

    2001-10-01

    A wellhead protection study for the city of Sturgeon Bay, Wisconsin, USA, demonstrates the necessity of combining detailed hydrostratigraphic analysis with groundwater modeling to delineate zones of contribution for municipal wells in a fractured dolomite aquifer. A numerical model (MODFLOW) was combined with a particle tracking code (MODPATH) to simulate the regional groundwater system and to delineate capture zones for municipal wells. The hydrostratigraphic model included vertical and horizontal fractures and high-permeability zones. Correlating stratigraphic interpretations with field data such as geophysical logs, packer tests, and fracture mapping resulted in the construction of a numerical model with five high-permeability zones related to bedding planes or facies changes. These zones serve as major conduits for horizontal groundwater flow. Dipping fracture zones were simulated as thin high-permeability layers. The locations of exposed bedrock and surficial karst features were used to identify areas of enhanced recharge. Model results show the vulnerability of the municipal wells to pollution. Capture zones for the wells extend several kilometers north and south from the city. Travel times from recharge areas to all wells were generally less than one year. The high seasonal variability of recharge in the study area made the use of a transient model necessary.

  20. Knee extension and flexion: MR delineation of normal and torn anterior cruciate ligaments

    SciTech Connect

    Niitsu, Mamoru; Ikeda, Kotaroh; Fukubayashi, Tohru; Anno, Izumi; Itai, Yuji

    1996-03-01

    Our goal was to assess the effect of joint position of semiflexed and extended knees in MR delineation of the anterior cruciate ligament (ACL). With a mobile knee brace and a flexible surface coil, the knee joint was either fully extended or bent to a semiflexed position (average 45{degrees} of flexion) within the magnet bore. Sets of oblique sagittal MR images were obtained for both extended and flexed knee positions. Thirty-two knees with intact ACLs and 43 knees with arthroscopically proven ACL tears were evaluated. Two observers compared paired MR images of both extended and flexed positions and rated them by a relative three point scale. Anatomic correlation in MR images was obtained by a cadaveric knee with incremental flexion. The MR images of flexed knees were more useful than of extended knees in 53% of the case reviews of femoral attachments and 36% of reviews of midportions of normal ACLs. Compared with knee extensions, the MR images for knee flexion provided better clarity in 48% of reviews of disrupted sites and 52% of residual bundles of torn ACLs. Normal ACL appeared taut in the knee extension and lax in semiflexion. Compared with MR images of knees in extension, MR images of knees in flexion more clearly delineate the femoral side of the ligament with wider space under the intercondylar roof and with decreased volume-averaging artifacts, providing superior visualization of normal and torn ACLs. 13 refs., 7 figs., 1 tab.

  1. Delineation of flood-prone areas and the identification of residential hotspots for two African cities

    NASA Astrophysics Data System (ADS)

    De Risi, Raffaele; Jalayer, Fatemeh; De Paola, Francesco; Iervolino, Iunio; Giugni, Maurizio; Topa, Maria Elena; Yonas, Nebyou; Nebebe, Alemu; Woldegerima, Tekle; Yeshitela, Kumelachew; Kibassa, Deusdedit; Shemdoe, Riziki; Cavan, Gina; Lindley, Sarah; Renner, Florian; Printz, Andreas

    2013-04-01

    This work employs two GIS-based frameworks for identifying the urban residential hot spots. This is done by overlaying a map of potentially flood prone areas (the topographic wetness index, TWI) and a map of urban morphology types (UMT) classified as residential. The topographic wetness index (TWI, Qin et al. 2011) allows for the delineation of a portion of a hydrographic basin potentially exposed to flood inundation by identifying all the areas characterized by a topographic index that exceeds a given threshold. The urban morphological types (Pauleit and Duhme 2000, Gill et al. 2008, Cavan et al. 2012) form the foundation of a classification scheme which brings together facets of urban form and function. The application of the UMTs allows the delineation of geographical units. The distinction of UMTs at a 'meso'-scale (i.e. between the city level and that of the individual units) makes a suitable basis for the spatial analysis of cities. The TWI threshold value depends on the resolution of the digital elevation model (DEM), topology of the hydrographic basin (i.e. urban, peri-urban or rural) and the constructed infrastructure (Manfreda et al. 2011). This threshold value is usually calibrated based on the results of detailed delineation of the inundation profile for selected zones. In this study, the TWI threshold is calibrated based on the calculated inundation profiles for various return periods for selected zones within the basin through a Bayesian framework. The Bayesian framework enables the probabilistic characterization of the threshold value by calculating the complementary probability of false delineation of flood prone zones as a function of various threshold values. For a given return period, the probability of false delineation is calculated as the sum of the probability of indicating a zone flood prone which is not indicated as such by the inundation profile and the probability that a zone is indicated as not flood prone but indicated as flood prone by

  2. Cytisine-induced behavioral activation: delineation of neuroanatomical locus of action.

    PubMed

    Museo, E; Wise, R A

    1995-01-30

    Systemic injections of nicotine increase locomotor activity. The present study was designed to determine whether there is a circumscribed region in the ventral tegmentum that mediates the locomotor-activating effects of nicotine. The mapping technique was used to delineate this region: bilateral injections of cytisine (1 nmol/0.5 microliters per side) were made into sites in and around the ventral tegmentum and the amount of locomotion associated with each site was quantified. The distribution of injection sites spanned between 0.8 and 4.6 mm posterior to bregma. The amount of locomotion varied with relation to the area into which cytisine was injected and a region was identified within which injections of cytisine preferentially increased locomotion. This region appears to have reasonably well-defined anterior and posterior boundaries. Since a portion of the delineated area overlaps the dopamine-containing cell-body region, the possibility remains that the activation of the mesolimbic dopamine system may contribute to the behavioral activation associated with ventral tegmental injections of cytisine. This same system may contribute to the locomotor-activating effects associated with systemic injections of nicotine.

  3. Enhancing in vivo tumor boundary delineation with structured illumination fluorescence molecular imaging and spatial gradient mapping

    NASA Astrophysics Data System (ADS)

    Sun, Jessica; Miller, Jessica P.; Hathi, Deep; Zhou, Haiying; Achilefu, Samuel; Shokeen, Monica; Akers, Walter J.

    2016-08-01

    Fluorescence imaging, in combination with tumor-avid near-infrared (NIR) fluorescent molecular probes, provides high specificity and sensitivity for cancer detection in preclinical animal models, and more recently, assistance during oncologic surgery. However, conventional camera-based fluorescence imaging techniques are heavily surface-weighted such that surface reflection from skin or other nontumor tissue and nonspecific fluorescence signals dominate, obscuring true cancer-specific signals and blurring tumor boundaries. To address this challenge, we applied structured illumination fluorescence molecular imaging (SIFMI) in live animals for automated subtraction of nonspecific surface signals to better delineate accumulation of an NIR fluorescent probe targeting α4β1 integrin in mice bearing subcutaneous plasma cell xenografts. SIFMI demonstrated a fivefold improvement in tumor-to-background contrast when compared with other full-field fluorescence imaging methods and required significantly reduced scanning time compared with diffuse optical spectroscopy imaging. Furthermore, the spatial gradient mapping enhanced highlighting of tumor boundaries. Through the relatively simple hardware and software modifications described, SIFMI can be integrated with clinical fluorescence imaging systems, enhancing intraoperative tumor boundary delineation from the uninvolved tissue.

  4. Automated delineation of karst sinkholes from LiDAR-derived digital elevation models

    NASA Astrophysics Data System (ADS)

    Wu, Qiusheng; Deng, Chengbin; Chen, Zuoqi

    2016-08-01

    Sinkhole mapping is critical for understanding hydrological processes and mitigating geological hazards in karst landscapes. Current methods for identifying sinkholes are primarily based on visual interpretation of low-resolution topographic maps and aerial photographs with subsequent field verification, which is labor-intensive and time-consuming. The increasing availability of high-resolution LiDAR-derived digital elevation data allows for an entirely new level of detailed delineation and analyses of small-scale geomorphologic features and landscape structures at fine scales. In this paper, we present a localized contour tree method for automated extraction of sinkholes in karst landscapes. One significant advantage of our automated approach for sinkhole extraction is that it may reduce inconsistencies and alleviate repeatability concerns associated with visual interpretation methods. In addition, the proposed method has contributed to improving the sinkhole inventory in several ways: (1) detection of non-inventoried sinkholes; (2) identification of previously inventoried sinkholes that have been filled; (3) delineation of sinkhole boundaries; and (4) characterization of sinkhole morphometric properties. We applied the method to Fillmore County in southeastern Minnesota, USA, and identified three times as many sinkholes as the existing database for the same area. The results suggest that previous visual interpretation method might significantly underestimate the number of potential sinkholes in the region. Our method holds great potential for creating and updating sinkhole inventory databases at a regional scale in a timely manner.

  5. An integrated approach for addressing uncertainty in the delineation of groundwater management areas

    NASA Astrophysics Data System (ADS)

    Sousa, Marcelo R.; Frind, Emil O.; Rudolph, David L.

    2013-05-01

    Uncertainty is a pervasive but often poorly understood factor in the delineation of wellhead protection areas (WHPAs), which can discourage water managers and practitioners from relying on model results. To make uncertainty more understandable and thereby remove a barrier to the acceptance of models in the WHPA context, we present a simple approach for dealing with uncertainty. The approach considers two spatial scales for representing uncertainty: local and global. At the local scale, uncertainties are assumed to be due to heterogeneities, and a capture zone is expressed in terms of a capture probability plume. At the global scale, uncertainties are expressed through scenario analysis, using a limited number of physically realistic scenarios. The two scales are integrated by using the precautionary principle to merge the individual capture probability plumes corresponding to the different scenarios. The approach applies to both wellhead protection and the mitigation of contaminated aquifers, or in general, to groundwater management areas. An example relates to the WHPA for a supply well located in a complex glacial aquifer system in southwestern Ontario, where we focus on uncertainty due to the spatial distributions of recharge. While different recharge scenarios calibrate equally well to the same data, they result in different capture probability plumes. Using the precautionary approach, the different plumes are merged into two types of maps delineating groundwater management areas for either wellhead protection or aquifer mitigation. The study shows that calibrations may be non-unique, and that finding a "best" model on the basis of the calibration fit may not be possible.

  6. An integrated approach for addressing uncertainty in the delineation of groundwater management areas.

    PubMed

    Sousa, Marcelo R; Frind, Emil O; Rudolph, David L

    2013-05-01

    Uncertainty is a pervasive but often poorly understood factor in the delineation of wellhead protection areas (WHPAs), which can discourage water managers and practitioners from relying on model results. To make uncertainty more understandable and thereby remove a barrier to the acceptance of models in the WHPA context, we present a simple approach for dealing with uncertainty. The approach considers two spatial scales for representing uncertainty: local and global. At the local scale, uncertainties are assumed to be due to heterogeneities, and a capture zone is expressed in terms of a capture probability plume. At the global scale, uncertainties are expressed through scenario analysis, using a limited number of physically realistic scenarios. The two scales are integrated by using the precautionary principle to merge the individual capture probability plumes corresponding to the different scenarios. The approach applies to both wellhead protection and the mitigation of contaminated aquifers, or in general, to groundwater management areas. An example relates to the WHPA for a supply well located in a complex glacial aquifer system in southwestern Ontario, where we focus on uncertainty due to the spatial distributions of recharge. While different recharge scenarios calibrate equally well to the same data, they result in different capture probability plumes. Using the precautionary approach, the different plumes are merged into two types of maps delineating groundwater management areas for either wellhead protection or aquifer mitigation. The study shows that calibrations may be non-unique, and that finding a "best" model on the basis of the calibration fit may not be possible.

  7. Delineations of power and power-to-flow feedback components of EBR-II

    SciTech Connect

    Meneghetti, D.; Kucera, D.A.

    1986-01-01

    The detailed contributions of feedback components by regions for various experimental breeder reactor-II (EBR-II) configurations have been reported assuming given values for the coolant flows. The separation of these components into power dependent and power-to-flow dependent parts if reported here for EBR-II run 93A. The power-reactivity-decrement (PRD) can then be expressed as the sum of parts which enables the PRD for other values of coolant flow to be estimated. The delineations of the components also enhance the understanding of the contributions of the various components and regions in the feedback process in EBR-II. Separation of the components into power and power-to-flow delineations were made by calculations of the components of the PRD assuming infinite coolant flow and comparing with results previously reported for finite flow. Subtractions of the infinite-flow feedback values from the corresponding finite-flow values give the power-to-flow portions. These linear and Doppler components of the PRDs were calculated using the EBRPOCO program together with an addition to the program (RODCO) which accounts for the effects of axial positionings of control rods.

  8. A full graphics processing unit implementation of uncertainty-aware drainage basin delineation

    NASA Astrophysics Data System (ADS)

    Eränen, David; Oksanen, Juha; Westerholm, Jan; Sarjakoski, Tapani

    2014-12-01

    Terrain analysis based on modern, high-resolution Digital Elevation Models (DEMs) has become quite time consuming because of the large amounts of data involved. Additionally, when the propagation of uncertainties during the analysis process is investigated using the Monte Carlo method, the run time of the algorithm can increase by a factor of between 100 and 1000, depending on the desired accuracy of the result. This increase in run time constitutes a large barrier when we expect the use of uncertainty-aware terrain analysis become more general. In this paper, we evaluate the use of Graphics Processing Units (GPUs) in uncertainty-aware drainage basin delineation. All computations are run on a GPU, including the creation of the realization of a stationary DEM uncertainty model, stream burning, pit filling, flow direction calculation, and the actual delineation of the drainage basins. On average, our GPU version is approximately 11 times faster than a sequential, one-core CPU version performing the same task.

  9. Improving superficial target delineation in radiation therapy with endoscopic tracking and registration

    SciTech Connect

    Weersink, R. A.; Qiu, J.; Hope, A. J.; Daly, M. J.; Cho, B. C. J.; DaCosta, R. S.; Sharpe, M. B.; Breen, S. L.; Chan, H.; Jaffray, D. A.

    2011-12-15

    Purpose: Target delineation within volumetric imaging is a critical step in the planning process of intensity modulated radiation therapy. In endoluminal cancers, endoscopy often reveals superficial areas of visible disease beyond what is seen on volumetric imaging. Quantitatively relating these findings to the volumetric imaging is prone to human error during the recall and contouring of the target. We have developed a method to improve target delineation in the radiation therapy planning process by quantitatively registering endoscopic findings contours traced on endoscopic images to volumetric imaging. Methods: Using electromagnetic sensors embedded in an endoscope, 2D endoscopic images were registered to computed tomography (CT) volumetric images by tracking the position and orientation of the endoscope relative to a CT image set. Regions-of-interest (ROI) in the 2D endoscopic view were delineated. A mesh created within the boundary of the ROI was projected onto the 3D image data, registering the ROI with the volumetric image. This 3D ROI was exported to clinical radiation treatment planning software. The precision and accuracy of the procedure was tested on two solid phantoms with superficial markings visible on both endoscopy and CT images. The first phantom was T-shaped tube with X-marks etched on the interior. The second phantom was an anatomically correct skull phantom with a phantom superficial lesion placed on the pharyngeal surface. Markings were contoured on the endoscope images and compared with contours delineated in the treatment planning system based on the CT images. Clinical feasibility was tested on three patients with early stage glottic cancer. Image-based rendering using manually identified landmarks was used to improve the registration. Results: Using the T-shaped phantom with X-markings, the 2D to 3D registration accuracy was 1.5-3.5 mm, depending on the endoscope position relative to the markings. Intraobserver standard variation was 0

  10. On the use of airborne LiDAR for braided river monitoring and water surface delineation

    NASA Astrophysics Data System (ADS)

    Vetter, M.; Höfle, B.; Pfeifer, N.; Rutzinger, M.; Stötter, J.

    2009-04-01

    Airborne LiDAR is an established technology for Earth surface surveying. With LiDAR data sets it is possible to derive maps with different land use classes, which are important for hydraulic simulations. We present a 3D point cloud based method for automatic water surface delineation using single as well as multitemporal LiDAR data sets. With the developed method it is possible to detect the location of the water surface with high planimetric accuracy. The multitemporal analysis of different LiDAR data sets makes it possible to visualize, monitor and quantify the changes of the flow path of braided rivers as well as derived water surface land use classes. The reflection properties from laser beams (1064 nm wavelength) on water surfaces are characterized by strong absorption or specular reflection resulting in a dominance of low signal amplitude values and a high number of laser shot dropouts (i.e. non-recorded laser echoes). The occurrence of dropouts is driven by (i) the incidence angle, (ii) the surface reflectance and (iii) the roughness of the water body. The input data of the presented delineation method are the modeled dropouts and the point cloud attributes of geometry and signal amplitude. A terrestrial orthophoto is used to explore the point cloud in order to find proper information about the geometry and amplitude attributes that are characteristic for water surfaces. The delineation method is divided into five major steps. (a) We compute calibrated amplitude values by reducing the atmospheric, topographic influences and the scan geometry for each laser echo. (b) Then, the dropouts are modeled by using the information from the time stamps, the pulse repetition frequency, the inertial measurement unit and the GPS information of the laser shots and the airplane. The next step is to calculate the standard deviation of the heights for all reflections and all modeled dropouts (c) in a specific radius around the points. (d) We compute the amplitude ratio

  11. The cold-water climate shield: delineating refugia for preserving salmonid fishes through the 21st century.

    PubMed

    Isaak, Daniel J; Young, Michael K; Nagel, David E; Horan, Dona L; Groce, Matthew C

    2015-02-27

    The distribution and future fate of ectothermic organisms in a warming world will be dictated by thermalscapes across landscapes. That is particularly true for stream fishes and cold-water species like trout, salmon, and char that are already constrained to high elevations and latitudes. The extreme climates in those environments also preclude invasions by most non-native species, so identifying especially cold habitats capable of absorbing future climate change while still supporting native populations would highlight important refugia. By coupling crowd-sourced biological datasets with high-resolution stream temperature scenarios, we delineate network refugia across >250 000 stream km in the Northern Rocky Mountains for two native salmonids-bull trout (BT) and cutthroat trout (CT). Under both moderate and extreme climate change scenarios, refugia with high probabilities of trout population occupancy (>0.9) were predicted to exist (33-68 BT refugia; 917-1425 CT refugia). Most refugia are on public lands (>90%) where few currently have protected status in National Parks or Wilderness Areas (<15%). Forecasts of refuge locations could enable protection of key watersheds and provide a foundation for climate smart planning of conservation networks. Using cold water as a 'climate shield' is generalizable to other species and geographic areas because it has a strong physiological basis, relies on nationally available geospatial data, and mines existing biological datasets. Importantly, the approach creates a framework to integrate data contributed by many individuals and resource agencies, and a process that strengthens the collaborative and social networks needed to preserve many cold-water fish populations through the 21st century.

  12. A multimodality segmentation framework for automatic target delineation in head and neck radiotherapy a)

    PubMed Central

    Yang, Jinzhong; Beadle, Beth M.; Garden, Adam S.; Schwartz, David L.; Aristophanous, Michalis

    2015-01-01

    Purpose: To develop an automatic segmentation algorithm integrating imaging information from computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) to delineate target volume in head and neck cancer radiotherapy. Methods: Eleven patients with unresectable disease at the tonsil or base of tongue who underwent MRI, CT, and PET/CT within two months before the start of radiotherapy or chemoradiotherapy were recruited for the study. For each patient, PET/CT and T1-weighted contrast MRI scans were first registered to the planning CT using deformable and rigid registration, respectively, to resample the PET and magnetic resonance (MR) images to the planning CT space. A binary mask was manually defined to identify the tumor area. The resampled PET and MR images, the planning CT image, and the binary mask were fed into the automatic segmentation algorithm for target delineation. The algorithm was based on a multichannel Gaussian mixture model and solved using an expectation–maximization algorithm with Markov random fields. To evaluate the algorithm, we compared the multichannel autosegmentation with an autosegmentation method using only PET images. The physician-defined gross tumor volume (GTV) was used as the “ground truth” for quantitative evaluation. Results: The median multichannel segmented GTV of the primary tumor was 15.7 cm3 (range, 6.6–44.3 cm3), while the PET segmented GTV was 10.2 cm3 (range, 2.8–45.1 cm3). The median physician-defined GTV was 22.1 cm3 (range, 4.2–38.4 cm3). The median difference between the multichannel segmented and physician-defined GTVs was −10.7%, not showing a statistically significant difference (p-value = 0.43). However, the median difference between the PET segmented and physician-defined GTVs was −19.2%, showing a statistically significant difference (p-value =0.0037). The median Dice similarity coefficient between the multichannel segmented and physician-defined GTVs was 0

  13. Target Volume Delineation in Oropharyngeal Cancer: Impact of PET, MRI, and Physical Examination

    SciTech Connect

    Thiagarajan, Anuradha; Caria, Nicola; Schoeder, Heiko; Iyer, N. Gopalakrishna; Wolden, Suzanne; Wong, Richard J.; Sherman, Eric; Fury, Matthew G.; Lee, Nancy

    2012-05-01

    Introduction: Sole utilization of computed tomography (CT) scans in gross tumor volume (GTV) delineation for head-and-neck cancers is subject to inaccuracies. This study aims to evaluate contributions of magnetic resonance imaging (MRI), positron emission tomography (PET), and physical examination (PE) to GTV delineation in oropharyngeal cancer (OPC). Methods: Forty-one patients with OPC were studied. All underwent contrast-enhanced CT simulation scans (CECTs) that were registered with pretreatment PETs and MRIs. For each patient, three sets of primary and nodal GTV were contoured. First, reference GTVs (GTVref) were contoured by the treating radiation oncologist (RO) using CT, MRI, PET, and PE findings. Additional GTVs were created using fused CT/PET scans (GTVctpet) and CT/MRI scans (GTVctmr) by two other ROs blinded to GTVref. To compare GTVs, concordance indices (CI) were calculated by dividing the respective overlap volumes by overall volumes. To evaluate the contribution of PE, composite GTVs derived from CT, MRI, and PET (GTVctpetmr) were compared with GTVref. Results: For primary tumors, GTVref was significantly larger than GTVctpet and GTVctmr (p < 0.001). Although no significant difference in size was noted between GTVctpet and GTVctmr (p = 0.39), there was poor concordance between them (CI = 0.62). In addition, although CI (ctpetmr vs. ref) was low, it was significantly higher than CI (ctpet vs. ref) and CI (ctmr vs. ref) (p < 0.001), suggesting that neither modality should be used alone. Qualitative analyses to explain the low CI (ctpetmr vs. ref) revealed underestimation of mucosal disease when GTV was contoured without knowledge of PE findings. Similar trends were observed for nodal GTVs. However, CI (ctpet vs. ref), CI (ctmr vs. ref), and CI (ctpetmr vs. ref) were high (>0.75), indicating that although the modalities were complementary, the added benefit was small in the context of CECTs. In addition, PE did not aid greatly in nodal GTV delineation

  14. Evaluation of methodology for delineation of protection zones around public-supply wells in west-central Florida

    USGS Publications Warehouse

    Vecchioli, John; Hunn, J.D.; Aucott, W.R.

    1989-01-01

    Public-supply wells in the west-central Florida area of Citrus, Hernando, Pasco, Hillsborough, and Pinellas Counties derive their supply solely from the Floridan aquifer system. In much of this area, the Floridan is at or near land surface and vulnerable to contamination. Recognizing this potential threat to the aquifer, the Florida Department of Environmental Regulation (FDER) recently promulgated regulations providing for the delineation of protection zones around public-supply wells that tap vulnerable aquifers, such as the Floridan in west-central Florida. This report evaluates the methodology for delineation of protection zones for public supply wells in west-central Florida in accordance with the methods detailed in the FDER regulations. Protection zones were delineated for public supply wells or well fields that are permitted an average daily withdrawal of 100,000 gal or more from the Floridan aquifer system where it is unconfined or leaky confined. Leaky confined, as used in FDER regulations describe conditions such that the time for a particle of water to travel vertically from the water table to the top of the Floridan is 5 years or less. Protection zones were delineated by using a radial volumetric-displacement model that simulated 5 years of permitted-rate withdrawal. Where zones overlapped, such as for well fields, composite protection zones in shapes that varied according to the configuration of well arrays were delineated on maps. (USGS)

  15. Uncertainties in target volume delineation in radiotherapy – are they relevant and what can we do about them?

    PubMed Central

    Segedin, Barbara

    2016-01-01

    Abstract Background Modern radiotherapy techniques enable delivery of high doses to the target volume without escalating dose to organs at risk, offering the possibility of better local control while preserving good quality of life. Uncertainties in target volume delineation have been demonstrated for most tumour sites, and various studies indicate that inconsistencies in target volume delineation may be larger than errors in all other steps of the treatment planning and delivery process. The aim of this paper is to summarize the degree of delineation uncertainties for different tumour sites reported in the literature and review the effect of strategies to minimize them. Conclusions Our review confirmed that interobserver variability in target volume contouring represents the largest uncertainty in the process for most tumour sites, potentially resulting in a systematic error in dose delivery, which could influence local control in individual patients. For most tumour sites the optimal combination of imaging modalities for target delineation still needs to be determined. Strict use of delineation guidelines and protocols is advisable both in every day clinical practice and in clinical studies to diminish interobserver variability. Continuing medical education of radiation oncologists cannot be overemphasized, intensive formal training on interpretation of sectional imaging should be included in the program for radiation oncology residents. PMID:27679540

  16. Delineation of electric and magnetic field effects of extremely low frequency electromagnetic radiation on transcription

    SciTech Connect

    Greene, J.J.; Skowronski, W.J.; Mullins, J.M.; Nardone, R.M.; Penafiel, M.; Meister, R. )

    1991-01-31

    The relative effects of the electric and magnetic field components of extremely low frequency electromagnetic radiation (ELF) on transcription were examined in human leukemia HL-60 cells. Delineation of the individual field contributions was achieved by irradiating cells in separate concentric compartments of a culture dish within a solenoid chamber. This exposure system produced a homogeneous magnetic field with a coincident electric field whose strength varied directly with distance from the center of the culture dish. Irradiation of HL-60 cells with sine wave ELF at 60 Hz and a field strength of 10 Gauss produced a transient increase in the transcriptional rates which reached a maximum of 50-60% enhancement at 30-120 minutes of irradiation and declined to near basal levels by 18 hours. Comparison of transcription responses to ELF of cells in different concentric compartments revealed that the transcriptional effects were primarily the result of the electric field component with little or no contribution from the magnetic field.

  17. A role delineation study of health educators in the United States: methodological innovations.

    PubMed

    Taub, Alyson; Olsen, Larry K; Gilmore, Gary D; Connell, David

    2008-12-01

    This paper focuses on methodological innovations used in the National Health Educator Competencies Update Project (CUP) in the United States. The CUP was a six-year research study designed to delineate the role of the health educator in the USA. Individuals who self-identified as health educators were included in the study. To provide context, the background for the research is presented, followed by a brief overview of the research process. Some of the key methodological innovations discussed are: selecting a representative sample when the total population of those working as health educators was not easily identified or readily accessible; assessing response methodology preferences through pilot studies; enhancing the response rate through accurate, up-to-date mailing lists and incentives; and exploring new approaches to large-scale data analyses. Insights gained are included for other researchers who may wish to undertake similar studies or draw from the CUP dataset for secondary analyses.

  18. Delineating taxonomic boundaries in the largest species complex of black flies (Simuliidae) in the Oriental Region

    PubMed Central

    Low, Van Lun; Takaoka, Hiroyuki; Pramual, Pairot; Adler, Peter H.; Ya’cob, Zubaidah; Huang, Yao-Te; Da Pham, Xuan; Ramli, Rosli; Chen, Chee Dhang; Wannaket, Anukhcha; Sofian-Azirun, Mohd

    2016-01-01

    Perspicuous assessments of taxonomic boundaries and discovery of cryptic taxa are of paramount importance in interpreting ecological and evolutionary phenomena among black flies (Simuliidae) and combating associated vector-borne diseases. Simulium tani Takaoka & Davies is the largest and perhaps the most taxonomically challenging species complex of black flies in the Oriental Region. We use a DNA sequence-based method to delineate currently recognized chromosomal and morphological taxa in the S. tani complex on the Southeast Asian mainland and Taiwan, while elucidating their phylogenetic relationships. A molecular approach using multiple genes, coupled with morphological and chromosomal data, supported recognition of cytoform K and morphoform ‘b’ as valid species; indicated that S. xuandei, cytoform L, and morphoform ‘a’ contain possible cryptic species; and suggested that cytoform B is in the early stages of reproductive isolation whereas lineage sorting is incomplete in cytoforms A, C, and G. PMID:26839292

  19. Delineating taxonomic boundaries in the largest species complex of black flies (Simuliidae) in the Oriental Region.

    PubMed

    Low, Van Lun; Takaoka, Hiroyuki; Pramual, Pairot; Adler, Peter H; Ya'cob, Zubaidah; Huang, Yao-Te; Da Pham, Xuan; Ramli, Rosli; Chen, Chee Dhang; Wannaket, Anukhcha; Sofian-Azirun, Mohd

    2016-02-03

    Perspicuous assessments of taxonomic boundaries and discovery of cryptic taxa are of paramount importance in interpreting ecological and evolutionary phenomena among black flies (Simuliidae) and combating associated vector-borne diseases. Simulium tani Takaoka & Davies is the largest and perhaps the most taxonomically challenging species complex of black flies in the Oriental Region. We use a DNA sequence-based method to delineate currently recognized chromosomal and morphological taxa in the S. tani complex on the Southeast Asian mainland and Taiwan, while elucidating their phylogenetic relationships. A molecular approach using multiple genes, coupled with morphological and chromosomal data, supported recognition of cytoform K and morphoform 'b' as valid species; indicated that S. xuandei, cytoform L, and morphoform 'a' contain possible cryptic species; and suggested that cytoform B is in the early stages of reproductive isolation whereas lineage sorting is incomplete in cytoforms A, C, and G.

  20. Improvement of water resources management through the use of satellites flood plain delineation

    NASA Technical Reports Server (NTRS)

    Castruccio, P. A.; Rango, A.

    1974-01-01

    The delineation of flood-prone areas is an important activity in several parts of the world. Conventional methods map the topography surrounding the river via ground surveys and supplementary aerophotography. The conventional method costs approximately $2,000 per river-kilometer, is laborious and time-consuming. ERTS information can supplement this method by two complementary techniques: (1) the dynamic method images the floods as they occur, exploiting the fact that visible evidence of inundation remains for a substantial period after the high waters have receded; (2) the static method utilizes the fact that several flood plains have been found recognizable on ERTS imagery from distinctive, permanent indicators left by previous floods. For areas whose full development is still in the future, the dynamic method allows the gradual buildup with time of a flood plain map, by simply correlating existing ERTS imagery. The static method allows in several areas, a first-cut indication, of proneness to floods.

  1. Delineating forested river habitats and riparian floodplain hydrology with LiDAR

    NASA Astrophysics Data System (ADS)

    Vondrasek, Chris

    Rivers and the riparian forest corridor comprise a valuable freshwater ecosystem that has been altered by human activities including timber management, road building, and other land conversions. The habitats of river dependent species in the Pacific Northwest, in particular salmon have often been degraded by these activities. Many salmon runs have become threatened with extinction and have been Endangered Species Act listed. New conservation planning and policies have developed around protecting freshwater habitats and restoring more natural river processes. In WA State, timber landowners, officials from State and Federal agencies, Native tribes, and other stakeholders developed Forest Practice rules and codified a Habitat Conservation Plan with dual goals of providing regulatory surety for timber land owners and helping to recover the threatened salmon runs in forested watersheds. Conserving critical stream ecological functions and potential fish habitats throughout watersheds while managing and regulating timber harvest across the State requires accurate and up-to-date delineation and mapping of channels, tributaries, and off-channel wetlands. Monitoring the effectiveness of protection efforts is necessary but can also be difficult. Agency staff and resources are limited for both day-to-day implementation of Forest Practice rules and adaptive management. The goal of this research has been to develop efficient and accessible methods to delineate wetlands, side-channels, tributaries, and pools and backwaters created by large log jams in forested watersheds. It was also essential to use publicly available LiDAR data and to model these waters at ecologically meaningful flows. I tested a hydraulic model at a 2-year and 50-year flows, and a relative height above river surface model and compared them. I completed two additional remote sensing investigations to correlate channel movement and the locations of off-channel wetlands: an analysis of historical aerial imagery

  2. Familial Congenital Unilateral Cerebral Ventriculomegaly: Delineation of a Distinct Genetic Disorder

    PubMed Central

    Zaki, Maha S.; Afifi, Hanan H.; Barkovich, AJ.; Gleeson, Joseph G.

    2016-01-01

    We identified two female siblings, derived from healthy first cousin parents, with congenital unilateral cerebral ventriculomegaly detected prenatally. Patient 1 underwent ventriculoperitoneal shunt operation at 1 week old, while Patient 2 was followed without surgical intervention. Both patients presented with mild developmental delay and hemiparesis contralateral to the involved hemisphere. Focal seizures were observed in Patient 1, whose neuroimaging revealed posterior insular polymicrogyria in the normal sized ventricle hemisphere and retrocerebellar cyst. Both siblings displayed near absence of white matter with marked thinning of the overlying cortex in the affected hemisphere and very thin corpus callosum. Investigations revealed no other system involvement and karyotyping was normal. Normal TORCH screening in subsequent pregnancies, normal parental coagulation profile and undetectable maternal autoantibodies suggested against the possible role of extrinsic factors as an etiological factor for unilateral ventriculomegaly. Parents had normal brain imaging findings. We suggest delineation of a distinct developmental brain defect, most likely of autosomal recessive inheritance. PMID:19610102

  3. Effective delineation of urban flooded areas based on aerial ortho-photo imagery

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Guindon, Bert; Raymond, Don; Hong, Gang

    2016-10-01

    The combination of rapid global urban growth and climate change has resulted in increased occurrence of major urban flood events across the globe. The distribution of flooded area is one of the key information layers for applications of emergency planning and response management. While SAR systems and technologies have been widely used for flood area delineation, radar images suffer from range ambiguities arising from corner reflection effects and shadowing in dense urban settings. A new mapping framework is proposed for the extraction and quantification of flood extent based on aerial optical multi-spectral imagery and ancillary data. This involves first mapping of flood areas directly visible to the sensor. Subsequently, the complete area of submergence is estimated from this initial mapping and inference techniques based on baseline data such as land cover and GIS information such as available digital elevation models. The methodology has been tested and proven effective using aerial photography for the case of the 2013 flood in Calgary, Canada.

  4. Delineating role of ubiquitination on nuclear factor-kappa B pathway by a computational modeling approach

    SciTech Connect

    Lee, Jungsul; Choi, Kyungsun; Choi, Chulhee

    2010-01-01

    Mutant ubiquitin found in neurodegenerative diseases has been thought to hamper activation of transcription factor nuclear factor-kappa B (NF-{kappa}B) by inhibiting ubiquitin-proteasome system (UPS). It has been reported that ubiquitin also is involved in signal transduction in an UPS-independent manner. We used a modeling and simulation approach to delineate the roles of ubiquitin on NF-{kappa}B activation. Inhibition of proteasome complex increased maximal activation of IKK mainly by decreasing the UPS efficiency. On the contrary, mutant ubiquitin decreased maximal activity of IKK. Computational modeling showed that the inhibition effect of mutant ubiquitin is mainly attributed to decreased activity of UPS-independent function of ubiquitin. Collectively, our results suggest that mutant ubiquitin affects NF-{kappa}B activation in an UPS-independent manner.

  5. Use of RAPD fingerprinting for delineating populations of hilsa shad Tenualosa ilisha (Hamilton, 1822).

    PubMed

    Brahmane, M P; Das, M K; Sinha, M R; Sugunan, V V; Mukherjee, A; Singh, S N; Prakash, S; Maurye, P; Hajra, A

    2006-10-31

    RAPD was used to delineate the hilsa populations sampled from the Ganga, Yamuna, Hooghly, and Narmada Rivers at six different locations. Six degenerate primers were used to generate the fragment patterns from the samples collected. All primers were highly polymorphic and generated high numbers of amplification products. Nei's genetic distances were calculated between locations. The overall average genetic distance among all the six locations was 0.295. The Fst value within the Ganga was 0.469 and within the Hooghly it was 0.546. The overall Fst value for the six populations analyzed was 0.590. The UPGMA dendrogram clustered the hilsa into two distinct clusters: Ganga and Yamuna populations and the Hooghly and Narmada populations.

  6. Anatomical delineation of congenital heart disease using 3D magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Adams Bornemeier, Renee; Fellows, Kenneth E.; Fogel, Mark A.; Weinberg, Paul M.

    1994-05-01

    Anatomic delineation of the heart and great vessels is a necessity when managing children with congenital heart disease. Spatial orientation of the vessels and chambers in the heart and the heart itself may be quite abnormal. Though magnetic resonance imaging provides a noninvasive means for determining the anatomy, the intricate interrelationships between many structures are difficult to conceptualize from a 2-D format. Taking the 2-D images and using a volumetric analysis package allows for a 3-D replica of the heart to be created. This model can then be used to view the anatomy and spatial arrangement of the cardiac structures. This information may be utilized by the physicians to assist in the clinical management of these children.

  7. Delineation of six species of the primitive algal genus Glaucocystis based on in situ ultrastructural characteristics

    PubMed Central

    Takahashi, Toshiyuki; Nishida, Tomoki; Tuji, Akihiro; Saito, Chieko; Matsuzaki, Ryo; Sato, Mayuko; Toyooka, Kiminori; Yasuda, Hidehiro; Nozaki, Hisayoshi

    2016-01-01

    The field of microbiology was established in the 17th century upon the discovery of microorganisms by Antonie van Leeuwenhoek using a single-lens microscope. Now, the detailed ultrastructures of microorganisms can be elucidated in situ using three-dimensional electron microscopy. Since the availability of electron microscopy, the taxonomy of microscopic organisms has entered a new era. Here, we established a new taxonomic system of the primitive algal genus Glaucocystis (Glaucophyta) using a new-generation electron microscopic methodology: ultra-high-voltage electron microscopy (UHVEM) and field-emission scanning electron microscopy (FE-SEM). Various globally distributed Glaucocystis strains were delineated into six species, based on differences in in situ ultrastructural features of the protoplast periphery under UHVEM tomography and in the mother cell wall by FE-SEM, as well as differences in the light microscopic characteristics and molecular phylogenetic results. The present work on Glaucocystis provides a model case of new-generation taxonomy. PMID:27383831

  8. Use of high-resolution ground-penetrating radar in kimberlite delineation

    USGS Publications Warehouse

    Kruger, J.M.; Martinez, A.; Berendsen, P.

    1997-01-01

    High-resolution ground-penetrating radar (GPR) was used to image the near-surface extent of two exposed Late Cretaceous kimberlites intruded into lower Permian limestone and dolomite host rocks in northeast Kansas. Six parallel GPR profiles identify the margin of the Randolph 1 kimberlite by the up-bending and termination of limestone reflectors. Five radially-intersecting GPR profiles identify the elliptical margin of the Randolph 2 kimberlite by the termination of dolomite reflectors near or below the kimberlite's mushroom-shaped cap. These results suggest GPR may augment magnetic methods for the delineation of kimberlites or other forceful intrusions in a layered host rock where thick, conductive soil or shale is not present at the surface.

  9. The utility of Landsat images in delineating volcanic cones in Harrat Kishb, Kingdom of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Chagarlamudi, P.; Moufti, M. R.

    1991-07-01

    The effectiveness of Landsat images is assessed with respect to the representation of cones and vents in a Cenozoic volcanic field. The images are analyzed visually by identifying volcanic cones from six sets of Landsat data and then comparing them to field observations and aerial photographs. The data are derived from the TM, MSS, and the RBV, and the results are measured for accuracy with a method that incorporates both commission and omission errors. The mapping accuracies for the TM, MSS, and RBV are 85, 70, and 80 percent respectively, and single-band images offer the same accuracies as color composites. The geometrical properties of the volcanic cones are described based on the images, and the cone orientation parallels a series of Cenozoic faults. The analysis of Landsat images is found to be an effective method for locating, delineating, and computing geometrical properties of volcanic cones and fields.

  10. A topological system for delineation and codification of the Earth's river basins

    USGS Publications Warehouse

    Verdin, K.L.; Verdin, J.P.

    1999-01-01

    A comprehensive reference system for the Earth's river basins is proposed as a support to fiver basin management, global change research, and the pursuit of sustainable development. A natural system for delineation and codification of basins is presented which is based upon topographic control and the topology of the fiver network. These characteristics make the system well suited for implementation and use with digital elevation models (DEMs) and geographic information systems. A demonstration of these traits is made with the 30-arcsecond GTOPO30 DEM for North America. The system has additional appeal owing to its economy of digits and the topological information that they carry. This is illustrated through presentation of comparisons with USGS hydrologic unit codes and demonstration of the use of code numbers to reveal dependence or independence of water use activities within a basin.

  11. Delineation of an octopus-like thrombus attached to the eustachian valve.

    PubMed

    Kalcik, Macit; Toprak, Cüneyt; Ozan Gursoy, M; Yesin, Mahmut; Ocal, Lutfi; Eren, Hayati; Özkan, Mehmet

    2014-04-01

    Eustachian valve (EV) is a vestige of the valve of the inferior vena cava which directs the umbilical vein blood through open foramen ovale in fetal life. Following birth it gradually regresses, but it may persist in variable size, shape, and thickness as a functionless and benign structure. However, there are reports suggesting that persistent EV may not be completely innocent. It has been accused of being a predisposing cause of patent foramen ovale and paradoxical embolism and also interfering with transseptal interventional procedures. It may serve as a site of infective vegetations and be mistaken as a tumor or thrombus. In the present case, an octopus-like thrombus attached to the EV was delineated with the utility of two-dimensional and real time three-dimensional transesophageal echocardiography. EV was considered to play an essential role in preventing potential pulmonary embolism.

  12. A whole body atlas for segmentation and delineation of organs for radiation therapy planning

    NASA Astrophysics Data System (ADS)

    Qatarneh, S. M.; Crafoord, J.; Kramer, E. L.; Maguire, G. Q.; Brahme, A.; Noz, M. E.; Hyödynmaa, S.

    2001-09-01

    A semi-automatic procedure for delineation of organs to be used as the basis of a whole body atlas database for radiation therapy planning was developed. The Visible Human Male Computed Tomography (CT)-data set was used as a "standard man" reference. The organ of interest was outlined manually and then transformed by a polynomial warping algorithm onto a clinical patient CT. This provided an initial contour, which was then adjusted and refined by the semi-automatic active contour model to find the final organ outline. The liver was used as a test organ for evaluating the performance of the procedure. Liver outlines obtained by the segmentation algorithm on six patients were compared to those manually drawn by a radiologist. The combination of warping and semi-automatic active contour model generally provided satisfactory segmentation results, but the procedure has to be extended to three dimensions.

  13. Rapid 3-D delineation of cell nuclei for high-content screening platforms.

    PubMed

    Gertych, Arkadiusz; Ma, Zhaoxuan; Tajbakhsh, Jian; Velásquez-Vacca, Adriana; Knudsen, Beatrice S

    2016-02-01

    High-resolution three-dimensional (3-D) microscopy combined with multiplexing of fluorescent labels allows high-content analysis of large numbers of cell nuclei. The full automation of 3-D screening platforms necessitates image processing algorithms that can accurately and robustly delineate nuclei in images with little to no human intervention. Imaging-based high-content screening was originally developed as a powerful tool for drug discovery. However, cell confluency, complexity of nuclear staining as well as poor contrast between nuclei and background result in slow and unreliable 3-D image processing and therefore negatively affect the performance of studying a drug response. Here, we propose a new method, 3D-RSD, to delineate nuclei by means of 3-D radial symmetries and test it on high-resolution image data of human cancer cells treated by drugs. The nuclei detection performance was evaluated by means of manually generated ground truth from 2351 nuclei (27 confocal stacks). When compared to three other nuclei segmentation methods, 3D-RSD possessed a better true positive rate of 83.3% and F-score of 0.895±0.045 (p-value=0.047). Altogether, 3D-RSD is a method with a very good overall segmentation performance. Furthermore, implementation of radial symmetries offers good processing speed, and makes 3D-RSD less sensitive to staining patterns. In particular, the 3D-RSD method performs well in cell lines, which are often used in imaging-based HCS platforms and are afflicted by nuclear crowding and overlaps that hinder feature extraction.

  14. Magnetic Resonance Imaging Protocol Optimization for Delineation of Gross Tumor Volume in Hypopharyngeal and Laryngeal Tumors

    SciTech Connect

    Verduijn, Gerda M.; Bartels, Lambertus W. Ph.D.; Pameijer, Frank A.

    2009-06-01

    Purpose: To optimize the use of MRI for delineation of gross tumor volume for radiotherapy treatment planning purposes in hypopharyngeal and laryngeal tumors. Methods and Materials: Magnetic resonance images (T1 weighted and T2 weighted) of a healthy volunteer were acquired using a 1.5 T and 3.0 T MR scanner. Various receiver coils were investigated that were compatible with the immobilization mask needed for reliable coregistration with computed tomography data. For the optimal receiver coil, the influence of resolution, slice thickness, and strength of magnetic field on the signal-to-noise ratio (SNR) was studied. Feasibility of the definitive protocol was tested on patients with hypopharyngeal (n = 19) and laryngeal (n = 42) carcinoma. Results: Large differences in SNR were obtained for the various coils. The SNR values obtained using surface coils that were compatible with the immobilization mask were three times higher than those obtained using a standard head-and-neck coil and five times higher than those obtained using a body coil. High-resolution images (0.4 x 0.4 x 4 mm{sup 3}) showed superior anatomic detail and resulted in a 4-min scan time. Image quality at 3.0 T was not significantly better compared with 1.5 T. In 3 patients the MR study could not be performed; for 5 patients images were severely deteriorated by motion artefacts. High-quality MR images were obtained in 53 patients. Conclusions: High-resolution MR images of the hypopharynx and larynx can be obtained in the majority of patients using surface receiver coils in combination with the radiotherapy mask. These MR images can be successfully used for tumor delineation in radiotherapy.

  15. An approach for delineating drinking water wellhead protection areas at the Nile Delta, Egypt.

    PubMed

    Fadlelmawla, Amr A; Dawoud, Mohamed A

    2006-04-01

    In Egypt, production has a high priority. To this end protecting the quality of the groundwater, specifically when used for drinking water, and delineating protection areas around the drinking water wellheads for strict landuse restrictions is essential. The delineation methods are numerous; nonetheless, the uniqueness of the hydrogeological, institutional as well as social conditions in the Nile Delta region dictate a customized approach. The analysis of the hydrological conditions and land ownership at the Nile Delta indicates the need for an accurate methodology. On the other hand, attempting to calculate the wellhead protected areas around each of the drinking wells (more than 1500) requires data, human resources, and time that exceed the capabilities of the groundwater management agency. Accordingly, a combination of two methods (simplified variable shapes and numerical modeling) was adopted. Sensitivity analyses carried out using hypothetical modeling conditions have identified the pumping rate, clay thickness, hydraulic gradient, vertical conductivity of the clay, and the hydraulic conductivity as the most significant parameters in determining the dimensions of the wellhead protection areas (WHPAs). Tables of sets of WHPAs dimensions were calculated using synthetic modeling conditions representing the most common ranges of the significant parameters. Specific WHPA dimensions can be calculated by interpolation, utilizing the produced tables along with the operational and hydrogeological conditions for the well under consideration. In order to simplify the interpolation of the appropriate dimensions of the WHPAs from the calculated tables, an interactive computer program was written. The program accepts the real time data of the significant parameters as its input, and gives the appropriate WHPAs dimensions as its output.

  16. A System for Continual Quality Improvement of Normal Tissue Delineation for Radiation Therapy Treatment Planning

    SciTech Connect

    Breunig, Jennifer; Hernandez, Sophy; Lin, Jeffrey; Alsager, Stacy; Dumstorf, Christine; Price, Jennifer; Steber, Jennifer; Garza, Richard; Nagda, Suneel; Melian, Edward; Emami, Bahman; Roeske, John C.

    2012-08-01

    Purpose: To implement the 'plan-do-check-act' (PDCA) cycle for the continual quality improvement of normal tissue contours used for radiation therapy treatment planning. Methods and Materials: The CT scans of patients treated for tumors of the brain, head and neck, thorax, pancreas and prostate were selected for this study. For each scan, a radiation oncologist and a diagnostic radiologist, outlined the normal tissues ('gold' contours) using Radiation Therapy Oncology Group (RTOG) guidelines. A total of 30 organs were delineated. Independently, 5 board-certified dosimetrists and 1 trainee then outlined the same organs. Metrics used to compare the agreement between the dosimetrists' contours and the gold contours included the Dice Similarity Coefficient (DSC), and a penalty function using distance to agreement. Based on these scores, dosimetrists were re-trained on those organs in which they did not receive a passing score, and they were subsequently re-tested. Results: Passing scores were achieved on 19 of 30 organs evaluated. These scores were correlated to organ volume. For organ volumes <8 cc, the average DSC was 0.61 vs organ volumes {>=}8 cc, for which the average DSC was 0.91 (P=.005). Normal tissues that had the lowest scores included the lenses, optic nerves, chiasm, cochlea, and esophagus. Of the 11 organs that were considered for re-testing, 10 showed improvement in the average score, and statistically significant improvement was noted in more than half of these organs after education and re-assessment. Conclusions: The results of this study indicate the feasibility of applying the PDCA cycle to assess competence in the delineation of individual organs, and to identify areas for improvement. With testing, guidance, and re-evaluation, contouring consistency can be obtained across multiple dosimetrists. Our expectation is that continual quality improvement using the PDCA approach will ensure more accurate treatments and dose assessment in radiotherapy

  17. Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists

    SciTech Connect

    Baldini, Elizabeth H.; Abrams, Ross A.; Bosch, Walter; Roberge, David; Haas, Rick L.M.; Catton, Charles N.; Indelicato, Daniel J.; Olsen, Jeffrey R.; Deville, Curtiland; Chen, Yen-Lin; Finkelstein, Steven E.; DeLaney, Thomas F.; Wang, Dian

    2015-08-01

    Purpose: The purpose of this study was to evaluate the variability in target volume and organ at risk (OAR) contour delineation for retroperitoneal sarcoma (RPS) among 12 sarcoma radiation oncologists. Methods and Materials: Radiation planning computed tomography (CT) scans for 2 cases of RPS were distributed among 12 sarcoma radiation oncologists with instructions for contouring gross tumor volume (GTV), clinical target volume (CTV), high-risk CTV (HR CTV: area judged to be at high risk of resulting in positive margins after resection), and OARs: bowel bag, small bowel, colon, stomach, and duodenum. Analysis of contour agreement was performed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. Results: Ten radiation oncologists contoured both RPS cases, 1 contoured only RPS1, and 1 contoured only RPS2 such that each case was contoured by 11 radiation oncologists. The first case (RPS 1) was a patient with a de-differentiated (DD) liposarcoma (LPS) with a predominant well-differentiated (WD) component, and the second case (RPS 2) was a patient with DD LPS made up almost entirely of a DD component. Contouring agreement for GTV and CTV contours was high. However, the agreement for HR CTVs was only moderate. For OARs, agreement for stomach, bowel bag, small bowel, and colon was high, but agreement for duodenum (distorted by tumor in one of these cases) was fair to moderate. Conclusions: For preoperative treatment of RPS, sarcoma radiation oncologists contoured GTV, CTV, and most OARs with a high level of agreement. HR CTV contours were more variable. Further clarification of this volume with the help of sarcoma surgical oncologists is necessary to reach consensus. More attention to delineation of the duodenum is also needed.

  18. The comparison of manual vs automated disc margin delineation using spectral-domain optical coherence tomography

    PubMed Central

    Iverson, S M; Sehi, M

    2013-01-01

    Aims To examine the impact of manual vs automated disc margin delineation on optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters using spectral-domain optical coherence tomography (SDOCT). Methods A prospective cohort study consisting of normal, glaucoma suspect (GS) and glaucoma patients who underwent ONH and RNFL measurements using SDOCT technology (RTVue; Optovue Inc.). The retinal pigment epithelium/Bruch's membrane (RPE/BM) complex end points were automatically determined first, and were manually redefined subsequently. Analysis of variance, coefficient of variation (COV), concordance correlation coefficient (CCC), and Bland–Altman plots were used for the analyses. Results Ninety-nine eyes of 50 subjects (age 68±10 years) consisting of 36 glaucoma, 56 GS, and 7 normal eyes were included. The RNFL thickness measurements were similar (P>0.05) between the two methods of demarcation, except for the inferior-nasal sector (P=0.04). For the ONH measurements, the cup-to-disc (C/D) ratio and rim area showed significant differences between the two methods (P<0.001). COV/CCC values for the ONH parameters were as follows: cup area 17.6%/0.88; cup volume 7.4%/0.91; average C/D ratio 18.1%/0.78; rim area 25.3%/0.69; and rim volume 42.6%/0.71, respectively. CCC/COV values for the RNFL parameters were as follows: average 2.1%/0.98; inferior-temporal quadrant 8.1%/0.79; inferior-nasal quadrant INQ quadrant 12.6%/0.67; SNQ quadrant 7.8%/0.83; and STQ quadrant 7.8%/0.88, respectively. Conclusion An overall high agreement and moderate–substantial concordance was observed between the demarcation methods. Automated disc margin delineation of SDOCT can be used reliably in clinical practice. PMID:23907624

  19. Delineation of Urban Active Faults Using Multi-scale Gravity Analysis in Shenzhen, South China

    NASA Astrophysics Data System (ADS)

    Xu, C.; Liu, X.

    2015-12-01

    In fact, many cities in the world are established on the active faults. As the rapid urban development, thousands of large facilities, such as ultrahigh buildings, supersized bridges, railway, and so on, are built near or on the faults, which may change the balance of faults and induce urban earthquake. Therefore, it is significant to delineate effectively the faults for urban planning construction and social sustainable development. Due to dense buildings in urban area, the ordinary approaches to identify active faults, like geological survey, artificial seismic exploration and electromagnetic exploration, are not convenient to be carried out. Gravity, reflecting the mass distribution of the Earth's interior, provides a more efficient and convenient method to delineate urban faults. The present study is an attempt to propose a novel gravity method, multi-scale gravity analysis, for identifying urban active faults and determining their stability. Firstly, the gravity anomalies are decomposed by wavelet multi-scale analysis. Secondly, based on the decomposed gravity anomalies, the crust is layered and the multilayer horizontal tectonic stress is inverted. Lastly, the decomposed anomalies and the inverted horizontal tectonic stress are used to infer the distribution and stability of main active faults. For validating our method, a case study on active faults in Shenzhen City is processed. The results show that the distribution of decomposed gravity anomalies and multilayer horizontal tectonic stress are controlled significantly by the strike of the main faults and can be used to infer depths of the faults. The main faults in Shenzhen may range from 4km to 20km in the depth. Each layer of the crust is nearly equipressure since the horizontal tectonic stress has small amplitude. It indicates that the main faults in Shenzhen are relatively stable and have no serious impact on planning and construction of the city.

  20. Postoperative radiation in esophageal squamous cell carcinoma and target volume delineation

    PubMed Central

    Zhu, Yingming; Li, Minghuan; Kong, Li; Yu, Jinming

    2016-01-01

    Esophageal cancer is the sixth leading cause of cancer death worldwide, and patients who are treated with surgery alone, without neoadjuvant therapies, experience frequent relapses. Whether postoperative therapies could reduce the recurrence or improve overall survival is still controversial for these patients. The purpose of our review is to figure out the value of postoperative adjuvant therapy and address the disputes about target volume delineation according to published data. Based on the evidence of increased morbidity and disadvantages on patient survival caused by postoperative chemotherapy or radiotherapy (RT) alone provided by studies in the early 1990s, the use of postoperative adjuvant therapies in cases of esophageal squamous cell carcinoma has diminished substantially and has been replaced gradually by neoadjuvant chemoradiation. With advances in surgery and RT, accumulating evidence has recently rekindled interest in the delivery of postoperative RT or chemoradiotherapy in patients with stage T3/T4 or N1 (lymph node positive) carcinomas after radical surgery. However, due to complications with the standard radiation field, a nonconforming modified field has been adopted in most studies. Therefore, we analyze different field applications and provide suggestions on the optimization of the radiation field based on the major sites of relapse and the surgical non-clearance area. For upper and middle thoracic esophageal carcinomas, the bilateral supraclavicular and superior mediastinal areas remain common sites of recurrence and should be encompassed within the clinical target volume. In contrast, a consensus has yet to be reached regarding lower thoracic esophageal carcinomas; the “standard” clinical target volume is still recommended. Further studies of larger sample sizes should focus on different recurrence patterns, categorized by tumor locations, refined classifications, and differing molecular biology, to provide more information on the