Note: This page contains sample records for the topic tailings dam failure from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Safety of Tailings Dams  

NSDL National Science Digital Library

Contains information on different aspects of tailings dams; tailings dam properties, disasters, failure modes, slurry waves, stability analysis, and safe tailings disposal. Also includes a slope stability calculator and a tailings flow slide calculator.

2008-08-25

2

Survey of Radionuclide Distributions Resulting from the Church Rock, New Mexico, Uranium Mill Tailings Pond Dam Failure.  

National Technical Information Service (NTIS)

In response to the uranium mill tailings pond dam failure on July 16, 1979, at Church Rock, New Mexico, the U.S. Nuclear Regulatory Commission through a contract with the Pacific Northwest Laboratory provided an on-site mobile laboratory capable of comple...

W. C. Weimer, R. R. Kinnison, J. H. Reeves

1981-01-01

3

Determination of the Failure Surface Geometry in Quick Slides Using Balanced Cross Section Techniques - Application to Aznalcóllar Tailings Dam Failure  

NASA Astrophysics Data System (ADS)

In a landslide investigation, the location of the failure surface is a difficult task when measures of subsurface displacement are lacking, as it occurs in old landslides or in recent but quick ones. The subsurface geological data and ground surface displacement data may not be enough to formulate a unique interpretation of the failure surface. However, an accurate determination of the failure surface is possible when balanced cross section techniques are applied to preliminary interpretations. The former is proved by means of the example of Aznalcóllar dam failure (Seville, Spain).

Moya, José

4

Internet Case Study #12: Dam Failure and Tailings Release at Aznalcóllar (Los Frailes), Spain - One Year Later  

Microsoft Academic Search

In the early morning of April 25, 1998, a 700-m-long portion of the tailings dam at Boliden's Minas de Aznalcóllar slid laterally up to nearly 70 m. This resulted in a dam breach which allowed acidic tailings water and sulphide-rich tailings solids to move rapidly through the breach and then downstream towards a national park and the ocean. The movement

Kevin A. Morin; M. Hutt

5

Determination of the Failure Surface Geometry in Quick Slides Using Balanced Cross Section Techniques - Application to Aznalcóllar Tailings Dam Failure  

Microsoft Academic Search

In a landslide investigation, the location of the failure surface is a difficult task when measures of subsurface displacement are lacking, as it occurs in old landslides or in recent but quick ones. The subsurface geological data and ground surface displacement data may not be enough to formulate a unique interpretation of the failure surface. However, an accurate determination of

José Moya

2004-01-01

6

Determination of the Failure Surface Geometry in Quick Slides Using Balanced Cross Section Techniques - Application to Aznalcóllar Tailings Dam Failure  

Microsoft Academic Search

In a landslide investigation, the location of the failure surface is a difficult task when measures of subsurface displacement are lacking, as it occurs in old landslides or in recent but quick ones. The subsurface geological data and ground surface displacement data may not be enough to formulate a unique interpretation of the failure surface. However, an accurate determination of

José Moya

7

Stability analysis of a copper tailings dam via laboratory model tests: A Chinese case study  

Microsoft Academic Search

The upstream method is a popular method for raising tailings dams. Currently in China there are more than 12,000 tailings impoundments and almost 95% of them use the upstream method for the construction of the dam. Statistical data has shown that the tailings impoundment is one of the main sources of risk in the mining industry. Failures of tailings impoundments

Guangzhi Yin; Guangzhi Li; Zuoan Wei; Ling Wan; Guohong Shui; Xiaofei Jing

2011-01-01

8

Survey of Radionuclide Distributions Resulting from the Church Rock, New Mexico, Uranium Mill Tailings Pond Dam Failure  

SciTech Connect

An intensive site survey and on-site analysis program were conducted to evaluate the distribution of four radionucliGes in the general vicinity of Gallup, New Mexico, subsequent to the accidental breach of a uranium mill tailings pond dam and the release of a large quantity of tailings pond materials. The objective of this work was to determine the distribution and concentration levels of {sup 210}Pb, {sup 226}Ra, {sup 230}Th, and {sup 238}U in the arroyo that is immediately adjacent to the uranium tailings pond (pipeline arroyo) and in the Rio Puerco arroyo into which the pipeline arroyo drains. An intensive survey between the United Nuclear Corporation (UNC) Church Rock Mill site and the New Mexico-Arizona state border was performed. Sampling locations were established at approximately 500-ft intervals along the arroyo. During the weeks of September 24 through October 5, 1979, a series of samples was collected from alternate sampling locations along the arroyo. The purpose of this collection of samples and their subsequent analysis was to provide an immediate evaluation of the extent and the levels of radioactive contamination. The data obtained from this extensive survey were then compared to action levels which had been proposed by the Nuclear Regulatory Commission and were adapted by the New Mexico Environmental Improvement Division (NMEID) for {sup 230}Th and {sup 226}Ra concentrations that would require site cleanup. The Pacific Northwest Laboratory/Nuclear Regulatory Commission mobile laboratory van was on-site at the UNC Church Rock Mill from September 22, 1979, through December 13, 1979, and was manned by one or more PNL personnel for all but four weeks of this time period. Approximately 1200 samples associated with the Rio Puerco survey were analyzed 1n the laboratory. An additional 1200 samples related to the Rio Puerco cleanup operations which the United Nuclear Corporation was conducting were analyzed on-site in the mobile laboratory. The purpose of these analyses was to determine the effectiveness of the cleanup operations that were ongoing and to evaluate what additional cleanup would be required. This on-site analysis of radioactive contamination constituted the principal task of this project, with the identification of those portions of the arroyo exceeding the NMEID proposed cleanup criteria being the major output. Additiond1 tasks included an evaluation of the initial soil sampling scheme (letter from T. Wolff [NMEID] to J. Abiss [UNC]. oated September 25, 1979) and the proposed NMEID verification sampling scheme (letter from T. Buhl [NMEID] to H. Miller [NRC]. dated April 23, 1980).

Weimer, W. C.; Kinnison, R. R.; Reeves, J. H.

1981-12-01

9

Groundwater pollution due to a tailings dam  

Microsoft Academic Search

In 1982, the Oman Mining Company (OMC) commenced copper mining and smelting operations in the area of Sohar (Wadi Suq), Sultanate of Oman. Seawater was used for mining operations until 1993. During this period, 11 million tonnes of tailings had been deposited behind an unlined tailings dam. This has resulted in a major groundwater pollution problem.This paper presents results from

R. S Sharma; T. S Al-Busaidi

2001-01-01

10

3. VIEW OF WEST TAILING DAM, LARGE TANK, AND TAILING, ...  

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

3. VIEW OF WEST TAILING DAM, LARGE TANK, AND TAILING, LOOKING NORTHEAST. A SIX-FOOT SCALE IS LOCATED AGAINST WALL ON LEFT. PURPOSE OF TANK IS UNKNOWN, BUT APPEARS TO HAVE FALLEN FROM ITS ORIGINAL LOCATION AT THE MILL SITE, UP AND TO THE RIGHT OF THIS VIEW. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

11

Design of tailing dam using red mud  

NASA Astrophysics Data System (ADS)

Red mud, waste industrial product from aluminum industries produced approximately 75 million tonnes every year with less than half of this is used. Storage of this unutilized red mud takes vast tracts of usable land and pollutes, land, air and water. Construction of high embankments, under passes, flyovers, tailing dams uses vast tract of natural resources (top soil) is also matter of concern as its takes thousands of years to form the natural soil. This paper discusses use of red mud for construction of tailing dam based on laboratory findings and finite element analysis. The geotechnical properties such as plasticity, compaction, permeability, shear strength characteristics and dispersion of red mud are presented. Stability and seepage analysis of tailing dams as per finite element analysis using the above geotechnical parameters is presented.

Rout, Subrat K.; Sahoo, Tapaswini; Das, Sarat K.

2013-06-01

12

12. Credit PED. View of tail race and dam showing ...  

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

12. Credit PED. View of tail race and dam showing dumping of construction rubble into river bed by rail car; and preparations for pouring a concrete cap onto tail race wall. Photo c. 1909. - Dam No. 4 Hydroelectric Plant, Potomac River, Martinsburg, Berkeley County, WV

13

Earth Dam Sliding Failure: Aznalcóllar Dam, Spain  

Microsoft Academic Search

\\u000a Mines in the area of Aznalcóllar, a town in the province of Sevilla, southwest Spain, have exploited from ancient times a\\u000a number of metallic minerals (zinc, lead, silver) associated with pyritic formations. The process of mineral extraction produces\\u000a large volumes of pyritic tailings which, in the Aznalcóllar mine, were stored under water in a large pond area. The pond,\\u000a whose

Eduardo E. Alonso; Núria M. Pinyol; Alexander M. Puzrin

14

Environmentally safe design of tailing dams for the management of iron ore tailings in Indian context.  

PubMed

The need for the disposal of iron ore tailings in an enviornmentally firiendly manner is of great concern. This paper investigates the soil engineering properties for the construction of iron ore tailing dam, its foundation, construction materials and design data used for the construction analysis of the tailing dam. Geophysical investigations were carried out to establish the bedrock below the spillway. A computer programme taking into account the Swedish Slip Circle Method of analysis was used in the stability analysis of dam. It also focuses on the charactierstics of the tailings reponsible for the determination of optimum size of tailing pond for the containment of the tailings. The studies on the settling characteristics of tailings indicate much less area in comparison to the area provided in the existing tailing ponds in India. In the proposed scheme, it is suggested to provide an additional unit of sedimentation tank before the disposal of tailings to the tailing pond. PMID:17051916

Ghose, Mrinal K; Sen, P K

2005-10-01

15

Dam Failure Inundation Map Project  

NASA Technical Reports Server (NTRS)

At the end of the first year, we remain on schedule. Property owners were identified and contacted for land access purposes. A prototype software package has been completed and was demonstrated to the Division of Land and Natural Resources (DLNR), National Weather Service (NWS) and Pacific Disaster Center (PDC). A field crew gathered data and surveyed the areas surrounding two dams in Waimea. (A field report is included in the annual report.) Data sensitivity analysis was initiated and completed. A user's manual has been completed. Beta testing of the software was initiated, but not completed. The initial TNK and property owner data collection for the additional test sites on Oahu and Kauai have been initiated.

Johnson, Carl; Iokepa, Judy; Dahlman, Jill; Michaud, Jene; Paylor, Earnest (Technical Monitor)

2000-01-01

16

2. VIEW OF EAST TAILING DAM (FOREGROUND), LOOKING EAST SOUTHEAST ...  

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

2. VIEW OF EAST TAILING DAM (FOREGROUND), LOOKING EAST SOUTHEAST UP WASH TOWARD ORE BIN, OVERBURDEN, ADITS, AND ROAD SHOWN IN CA-290-1. MILL SITE IS UP AND TO THE RIGHT OF THIS VIEW. STANDARD FIFTY-GALLON DRUM IN FOREGROUND GIVES SCALE OF WALL. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

17

Geochemical modeling of cyanide in tailing dam gold processing plant  

NASA Astrophysics Data System (ADS)

This research is aimed at investigating possible neutralization of cyanide in tailing dam of Muteh gold processing plant in Isfahan, Iran at various conditions such as pH and temperature using USEPA Visual MINTEQ geochemical model simulation. The model is based on geochemical equilibrium which uses the simultaneous solution of the non-linear mass action expressions and linear mass balance relationships to formulate and solve the multiple-component chemical equilibrium problems. In this study the concentration of aqueous species in tailing dam as an aqueous, solid and gaseous were used as input in the model. Temperature and pH variation were simulated. The results of the model indicated that cyanide may be complexes in 10 < pH < 5. In other pH values complexation is not important. The results also indicated that cyanide reduction mechanism in acidic pH and temperature above 30°C is due to cyanide acid formation which is vaporized.

Khodadadi, Ahmad; Monjezi, M.; Mehrpouya, H.; Dehghani, H.

2009-09-01

18

Geochemical modeling of cyanide in tailing dam gold processing plant  

Microsoft Academic Search

This research is aimed at investigating possible neutralization of cyanide in tailing dam of Muteh gold processing plant in\\u000a Isfahan, Iran at various conditions such as pH and temperature using USEPA Visual MINTEQ geochemical model simulation. The\\u000a model is based on geochemical equilibrium which uses the simultaneous solution of the non-linear mass action expressions and\\u000a linear mass balance relationships to

Ahmad Khodadadi; M. Monjezi; H. Mehrpouya; H. Dehghani

2009-01-01

19

Analysis of seismic disaster failure mechanism and dam-break simulation of high arch dam  

NASA Astrophysics Data System (ADS)

Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformable distinct element code (3DEC) and its re-development functions. The proposed analysis model considers the dam-foundation-reservoir coupling effect, influence of nonlinear contact in the opening and closing of the dam seam surface and abutment rock joints during strong earthquakes, and radiation damping of far field energy dissipation according to the actual workability state of an arch dam. A safety assessment method and safety evaluation criteria is developed to better understand the arch dam system disaster process from local damage to ultimate failure. The dynamic characteristics, disaster mechanism, limit bearing capacity and the entire failure process of a high arch dam under a strong earthquake are then analyzed. Further, the seismic safety of the arch dam is evaluated according to the proposed evaluation criteria and safety assessment method. As a result, some useful conclusions are obtained for some aspects of the disaster mechanism and failure process of an arch dam. The analysis method and conclusions may be useful in engineering practice.

Zhang, Jingkui; Zhang, Liaojun

2014-06-01

20

The geomorphic influences of beaver dams and failures of beaver dams  

NASA Astrophysics Data System (ADS)

Uncounted millions of beaver ponds and dams existed in North America prior to European contact and colonization. These ponds acted as sediment traps that contained tens to hundreds of billions of cubic meters of sediment that would otherwise have passed through the fluvial system. Removal of beavers by overtrapping in the 16th-19th centuries severely reduced their number and the number of ponds and dams. Dam removal altered the fluvial landscape of North America, inducing sediment evacuation and entrenchment in concert with widespread reduction in the wetlands environments. Partial recovery of beaver populations in the 20th century has allowed reoccupation of the entirety of the pre-contact range, but at densities of only one-tenth the numbers. Nevertheless, modern beaver ponds also trap large volumes of sediment in the high hundred millions to low billions of cubic meters range. Failure of beaver dams is a more common phenomenon than often assumed in the literature. During the past 20 years, numerous cases of dam failure have been documented that resulted in outburst floods. These floods have been responsible for 13 deaths and numerous injuries, including significant impacts on railway lines.

Butler, David R.; Malanson, George P.

2005-10-01

21

A New Method for System Reliability Analysis of Tailings Dam Stability  

NASA Astrophysics Data System (ADS)

For the purpose of stability evaluation, a tailings dam can be considered as an artificial slope made of special soil materials which mainly come from mine tailings. As a particular engineering project, a tailings dam generally has experienced multi-loop hydraulic sediments as well as a long-term consolidation in the process of construction. The characteristics of sediment and consolidation result in a unique distribution of the soil layers with significant uncertainties, which come from both nature development and various human activities, and thus cause the discrete and the variability of the physical-mechanical properties dramatically greater than the natural geo-materials. Therefore, the location of critical slip surface (CSS) of the dam usually presents a notable drift. So, it means that the reliability evaluation task for a tailings dam is a system reliability problem indeed. Unfortunately, the previous research of reliability of tailings dam was mainly confined to the limit equilibrium method (LEM), which has three obvious drawbacks. First, it just focused on the variability along the slip surface rather than the whole space of the dam. Second, a fixed CSS, instead of variable one, was concerned in most cases. Third, the shape of the CSS was usually simplified to a circular. The present paper tried to construct a new reliability analysis model combined with several advanced techniques involving finite difference method (FDM), Monte Carlo simulation (MCS), support vector machine (SVM) and particle swarm optimization (PSO). The new framework was consisted of four modules. The first one is the limit equilibrium finite difference mode, which employed the FLAC3D code to generate stress fields and then used PSO algorithm to search the location of CSS and corresponding minimum factor of safety (FOS). The most value of this module was that each realization of stress field would lead to a particular CSS and its FOS. In other words, the consideration of the drift of CSS was significant to system reliability analysis. Besides, the CSS was described with non-circular shape, which was much more superior to the circular one. Moreover, compare with the LEM, the numerical method has the ability to reflect the variability in a whole space of the dam. The second one is the orthogonal design modules aimed to generate high-quality training samples according to the variability of soil layers. The third one is the response surface model based on SVM, which was designed to obtain the explicit performance function through the well-prepared training samples. The fourth one is the MCS model, which can perform steady and effective reliability analysis through the explicit performance function. As a result, a new approach for reliability analysis of tailings dam stability was presented. As a case study, the Yong-ping Copper Mine Tailings Dam in Jiangxi Province of China was analyzed in detail by this new method. It was shown that the effectiveness of the new method is considerable. In sum, this research is geared towards providing new ideas and available examples for future reliability assessment of tailings dam stability.

Liu, X.; Tang, H.; Xiong, C.; Ni, W.

2012-12-01

22

Tail Behavior of the Failure Rate Functions of Mixtures  

Microsoft Academic Search

The tail behavior of the failure rate of mixtures of lifetime distributions is studied. A typical result is that if the failure\\u000a rate of the strongest component of the mixture decreases to a limit, then the failure rate of the mixture decreases to the\\u000a same limit. For a class of distributions containing the gamma distributions this result can be improved

Henry Block; Harry Joe

1997-01-01

23

Dynamics of Dam Sliding: Aznalcóllar Dam, Spain  

Microsoft Academic Search

\\u000a Aznalcóllar dam, a 28 m high rockfill dyke, failed catastrophically on April 25, 1998 and triggered an uncontrolled flow of\\u000a acid pyritic tailings whose volume was estimated in 5.5 Mm3. Chapter 4 describes the failure, the geotechnical properties of stored tailings and foundation soils and the stability analysis\\u000a performed to explain the reasons for the failure. The failure was described

Eduardo E. Alonso; Núria M. Pinyol; Alexander M. Puzrin

24

Hydrogeophysical Modeling of Spatial and Temporal Salt Flushing of a Tailings Dam  

NASA Astrophysics Data System (ADS)

The Southwest Sand Storage (SWSS) is a large tailings dam located at Syncrude Canada’s Mildred Lake Operations, 40 km north of Fort McMurray, Alberta. It is 25 km2 in area, up to 40 m high and contains 300 million cubic metres of tailings sand. Sand was mounded and compacted to form a perimeter dyke that consists of 10 m high slopes separated by benches that are either “tipped-in” or “tipped-out”. The dyke is undrained and has an overall shallow slope of 10:1. The pond within the dam receives a slurry of sand tailings containing about 50% (by weight) of process affected water with high concentrations of sodium, calcium, sulphate and bicarbonate ions. The performance and viability of the reclaimed and vegetated landform following closure was questioned because the landscape might be negatively affected by the movement and discharge of process affected water through the dam. Some degree of temporal salt flushing from the percolation of rainwater was anticipated, but the vertical and the lateral extent of this flushing could not be modeled in the absence of detailed field measurements. To quantify the spatial and temporal flushing of salt at SWSS, two detailed monitoring transects were established. Nests of piezometers were installed along each transect to obtain point measurements for hydraulic head, electrical conductivity, soil-moisture and temperature. Water samples were periodically collected from the piezometers and from multi-level sampling ports distributed across the watertable. To supplement and complement the hydrogeologic data, Electrical Resistivity Tomography (ERT) surveys were conducted concurrently with hydrogeologic data collection in 2001, 2004, and 2008. Electrical conductivity difference plots (DmS/m) illustrate temporal salt flushing along the transects. The results indicate that the degree of flushing is closely associated with groundwater flow system scale, recharge rates, and dyke topography. Tipped-in (i.e., relatively flat) benches result in higher recharge rates and deeper water tables that are more favourable to salt flushing and to enhanced separation between plant roots and salty groundwater, as compared to tipped-out (i.e., slightly sloped) benches. Similarly, local flow systems established over the bench scale have a greater tendency for flushing compared to intermediate flow systems that may require centuries to flush. The conductivity difference plots closely match the hydrogeologic data, thus demonstrating the effectiveness of ERT as a non-invasive technique to model salt flushing within a tailings dam.

Cheema, T. J.; Mendoza, C. A.; Price, A.

2009-12-01

25

Quantitative and Qualitative Geospatial Analysis of a Probable Catastrophic Dam Failure  

NASA Astrophysics Data System (ADS)

Geospatial techniques were used in assessing inundation extents that would occur in the event of a catastrophic failure of Fort Peck dam. Fort Peck dam, located in Montana, USA has a spillway design which under dam failure the crest is expected to reach Williston a major economic hub in North Dakota in 1.4 days with a peak elevation of 1891 ft (576.377 m) msl (mean sea level). In this study, we address flooding extents and impacts on establishments with respect to a peak elevation of 1891 ft. From this study, we can unequivocally state that the City of Williston will be significantly impacted if Fort Peck dam fails with almost all critical needs, for example, gasoline stations, emergency facilities and grocery stores completely inundated. A secondary catastrophic event may be tied to the primary economic activity in Williston, that is, oil rigs of which most lie on the pathway of an inadvertent flood crest. We also applied a Discrete Fourier Transformation (DFT), and Lomb-Scargle normalized periodogram analyses and fitting of Fort Peck dam reservoir level fluctuations to gauge (a) likelihood of the dam overtopping, and (b) anatomic life span. Whereas we found that inasmuch as the dam could be considered stable by directly analyzing other dams that have failed, there is still a lower likelihood of it to fail at a 99-232 years range from construction. There was lack of concomitancy between overtopping and dam failure rates.

Oduor, P. G.; Stenehjem, J.

2011-12-01

26

Residual Strength of Sand from Dam Failure in the Chilean Earthquake of March 3, 1985,  

National Technical Information Service (NTIS)

The slope failures at La Marquesa and La Palma Dams in the Chilean earthquake of March 3, 1985 were apparently due to liquefaction of loose sand layers near the base of the embankments. The dams were low structures (4 to 10 m high) and the horizontal move...

E. Retamal H. B. Seed P. De Alba R. B. Seed

1987-01-01

27

Groundwater Flow and Salt Transport at a Sand Tailings Dam: Field Observations and Modelling Results.  

NASA Astrophysics Data System (ADS)

Large volumes of sand tailings are produced during the extraction of bitumen from the oil sands of Northeastern Alberta. The long-term groundwater response and subsequent movement of water and solutes within the large permeable sand tailings storage areas is uncertain. At the Southwest Sand Storage (SWSS) Facility, located at Syncrude's Mildred Lake operations near Ft. McMurray, there is concern that salts from the tailings water may discharge to newly placed reclamation material that covers the sand tailings. This saline discharge water could destroy the reclamation soil structure and negatively impact vegetation. The steady-state groundwater flow and transient movement of salts at the local (bench and slope) and intermediate (pile) scales in the SWSS are investigated. Water levels, seepage and groundwater quality (including TDS) have been measured for over a year along two transects of piezometers installed in the SWSS. The field data have been used to complete traditional hydrogeological interpretations of the site, and to develop a conceptual model of flow and transport. The local and intermediate flow systems and salt transport in the dam are being evaluated with numerical models. The models will allow possible future hydrogeological behaviour of the structure to be tested. Preliminary results show differences in flow systems and salinity distribution that depend on the deposition of the SWSS. This research will facilitate better long-term environmental management of this and similar sites.

Price, A. C.; Mendoza, C. A.

2004-05-01

28

Seismic analysis of the Par Pond Dam: Study of slope failure and liquefaction. Technical evaluation report.  

National Technical Information Service (NTIS)

Stability concerns of the Par Pond Dam, an embankment structure in the Savannah River Site complex, resulted in a comprehensive evaluation of the state of its integrity. Specifically, excessive seepage through the embankment, slope failure due to an earth...

N. Simos M. Reich

1994-01-01

29

Scale amplification of natural debris flows caused by cascading landslide dam failures  

NASA Astrophysics Data System (ADS)

Debris flows are typically caused by natural terrain landslides triggered by intense rainfalls. If an incoming mountain torrent collapses a series of landslide dams, large debris flows can form in a very short period. Moreover, the torrent can amplify the scale of the debris flow in the flow direction. The catastrophic debris flows that occurred in Zhouqu, China, on 8 August 2010 were caused by intense rainfall and the upstream cascading failure of landslide dams along the gullies. In the wake of the incident, a field study was conducted to better understand the process of cascading landslide dam failures and the formation of debris flows. This paper looks at the geomorphic properties of the debris-flow gullies, estimates the peak flow discharges at different locations using three different methods, and analyzes the key modes (i.e., different landslide dam types and their combinations) of cascading landslide dam failures and their effect on the scale amplification of debris flows. The results show that five key modes in Luojiayu gully and two modes in Sanyanyu gully accounted for the scale amplification of downstream debris flows in the Zhouqu event. This study illustrates how the hazardous process of natural debris flows can begin several kilometers upstream as a complex cascade of geomorphic events (failure of landslide dams and erosion of the sloping bed) can scale to become catastrophic discharges. Neglecting recognition of these hazardous geomorphic and hydrodynamic processes may result in a high cost.

Cui, P.; Zhou, Gordon G. D.; Zhu, X. H.; Zhang, J. Q.

2013-01-01

30

Mineralogical characterization of tailing dams: incidence of abandoned mining works on soil pollution (Linares, Jaén)  

NASA Astrophysics Data System (ADS)

The metallogenic district of Linares-La Carolina (Jaén, Spain) consists of dyke mineralizations mainly of galena, accompanied by blende, chalcopyrite and barite. Associated to these abandoned mines, relatively extensive areas occupied by spoil heaps and tailing impoundments exist and constitute potential sources of soil pollution by metals and semimetals. In order to analyze the pollution potential of these mining wastes, we have carried out a mineralogical and geochemical study of seven tailing dams and surrounding soils in the area. The mineralogy of the samples was studied by x-ray diffraction (XRD) and scanning electron microscope (SEM). In addition, the total metal content of samples was determined by inductively coupled plasma mass spectrometry (ICP-MS) analysis. Samples were taken from the first 30 cm of the waste piles and soil deposits and white efflorescences were also obtained from the surface of the tailings. In all analyzed heaps, high to very high total contents in Pb (1220-22890 mg/kg), Zn (150-51280 mg/kg), Mn (2658-4160 mg/kg), Ba (1026-19610 mg/kg) and Fe (19400-138000 mg/kg) were observed. The concentrations for these same elements in the studied soils range from 527-9900 mg/kg for Pb, 27-1700 mg/kg for Zn, 506-2464 mg/kg for Mn, 2832-4306 for Ba and 8642-29753 mg/kg for Fe, and these figures indicate a contamination of the soils, according to the guidelines established by the Spanish law. The XRD and SEM results indicate that the tailings are primarily constituted by gangue of the exploited mineralization: quartz, calcite, ankerite, feldspars and phyllosilicates. They are inherited, primary mineral phases. Galena, also primary, appears in low proportion, as well as lepidocrocite, melanterite and cerussite, being these three last secondary minerals and indicating a certain remobilization of metal cations, especially lead and iron. On the other hand, quartz and phyllosilicates predominate in the soils, in which, in addition, is identified a little proportion of galena (primary mineral) and ferro-hexahydrite, also indicating mobilization of Fe. As regarding white surface blooms, they are formed mostly of magnesium sulphate with different hydration states. The morphology of these mineral precipitates reveals that they have been subject to cycle of washing and subsequent dehydration, which indicates that these phases present a great mobility in the environment, and they may be contributing to the transport of metals from the tailings into the surroundings soils.

de la Torre, M. J.; Hidalgo, C.; Rey, J.; Martínez, J.

2012-04-01

31

Spill Alert Device for Earth Dam Failure Warning.  

National Technical Information Service (NTIS)

A spill alert device for determining earth dam safety based on the monitoring of the acoustic emissions generated in a deforming soil mass was developed and field-tested. The acoustic emissions are related to the basic mechanisms from which soils derive t...

R. M. Koerner A. E. Lord

1984-01-01

32

Dams  

NSDL National Science Digital Library

National Geographic's Dams Web site offers an interactive investigation into the good and bad impacts of dam construction. Visitors choose to view a river system before, during, or after a dam is built. Then at each time interval they can click on various sections of the river and read a short description of what is happening there. For example, after the dam is built, the reservoir that is created upstream causes several hydrological problems such as loss of water from evaporation. Although the text provided on the site is somewhat lacking, the well-done graphics and interactivity make it worth a visit.

1997-01-01

33

Dams  

NSDL National Science Digital Library

Through eight lessons, students are introduced to many facets of dams, including their basic components, the common types (all designed to resist strong forces), their primary benefits (electricity generation, water supply, flood control, irrigation, recreation), and their importance (historically, currently and globally). Through an introduction to kinetic and potential energy, students come to understand how dams generate electricity. They learn about the structure, function and purpose of locks, which involves an introduction to Pascal's law, water pressure and gravity. Other lessons introduce students to common environmental impacts of dams and the engineering approaches to address them. They learn about the life cycle of salmon and the many engineered dam structures that aid in their river passage, as they think of their own methods and devices that could help fish migrate past dams. Students learn how dams and reservoirs become part of the Earth's hydrologic cycle, focusing on the role of evaporation. To conclude, students learn that dams do not last forever; they require ongoing maintenance, occasionally fail or succumb to "old age," or are no longer needed, and are sometimes removed. Through associated hands-on activities, students track their personal water usage; use clay and plastic containers to model and test four types of dam structures; use paper cups and water to learn about water pressure and Pascal's Law; explore kinetic energy by creating their own experimental waterwheel from two-liter plastic bottles; collect and count a stream's insects to gauge its health; play an animated PowerPoint game to quiz their understanding of the salmon life cycle and fish ladders; run a weeklong experiment to measure water evaporation and graph their data; and research eight dams to find out and compare their original purposes, current status, reservoir capacity and lifespan. Woven throughout the unit is a continuing hypothetical scenario in which students act as consulting engineers with a Splash Engineering firm, assisting Thirsty County in designing a dam for Birdseye River.

Integrated Teaching And Learning Program

34

The potential for catastrophic dam failure at Lake Nyos maar, Cameroon  

USGS Publications Warehouse

The upper 40 m of Lake Nyos is bounded on the north by a narrow dam of poorly consolidated pyroclastic rocks, emplaced during the eruptive formation of the Lake Nyos maar a few hundred years ago. This 50-m-wide natural dam is structurally weak and is being eroded at an uncertain, but geologically alarming, rate. The eventual failure of the dam could cause a major flood (estimated peak discharge, 17000 m3/s) that would have a tragic impact on downstream areas as far as Nigeria, 108 km away. This serious hazard could be eliminated by lowering the lake level, either by controlled removal of the dam or by construction of a 680-m-long drainage tunnel about 65 m below the present lake surface. Either strategy would also lessen the lethal effects of future massive CO2 gas releases, such as the one that occurred in August 1986. ?? 1988 Springer-Verlag.

Lockwood, J. P.; Costa, J. E.; Tuttle, M. L.; Nni, J.; Tebor, S. G.

1988-01-01

35

Seismic analysis of the Par Pond Dam: Study of slope failure and liquefaction. Technical evaluation report  

SciTech Connect

Stability concerns of the Par Pond Dam, an embankment structure in the Savannah River Site complex, resulted in a comprehensive evaluation of the state of its integrity. Specifically, excessive seepage through the embankment, slope failure due to an earthquake event as well as liquefaction potential of the embankment and the foundation are addressed and the potential of failure is evaluated. Lastly, remedial benefits of the addition of a berm structure are also assessed.

Simos, N.; Reich, M.

1994-07-01

36

The history and dynamics of a welded pyroclastic dam and its failure  

NASA Astrophysics Data System (ADS)

The 2,360 BP eruption of Mount Meager, British Columbia began as an explosive, dacitic sub-Plinian eruption that waned rapidly to a sustained period of Vulcanian, eruption-triggered dome collapse events producing voluminous block and ash flow (BAF) deposits. The earliest BAF deposits accumulated rapidly enough immediately downslope of the vent to retain heat and weld; using the deposit as a paleoviscometer determines an effective viscosity of 109-1010 Pa s during welding. This prolific production of hot lava and block and ash flows, in a steep mountainous terrain, created a ˜110 m high, largely impermeable dam capped by permeable, non-welded BAF deposits and unconsolidated avalanche deposits that blocked the flow of the Lillooet River and created a temporary lake. The welded pyroclastic dam was compromised and overtopped at least once before the peak dam height was reached. Renewed eruption caused buildup of the dam to a maximum of 780 m above sea level (asl) and grew the temporary lake to an elevation of 740 m asl and a minimum volume of 0.55 km3. The rise of lake level led to catastrophic failure of the top of the dam, generating an outburst flood that carved a canyon through most of the dam and resulted in a voluminous lahar that is traced at least 65 km downstream. Based on current flow rates of the Lillooet River, the lake would have overtopped the final dam at a minimum of 39-65 days after its formation. The peak deluge lasted approximately 8 h and eroded a 2.5-km long canyon into the still-hot dam core before returning to background flow rates.

Andrews, Graham D. M.; Russell, James K.; Stewart, Martin L.

2014-04-01

37

The impact of tailings dam spills and clean-up operations on sediment and water quality in river systems: the R??os Agrio–Guadiamar, Aznalcóllar, Spain  

Microsoft Academic Search

The Aznalcóllar tailings dam at Boliden Apirsa's Aznalcóllar\\/Los Frailes Ag–Cu–Pb–Zn mine 45 km west of Seville, Spain, was breached on 25 April 1998, flooding approximately 4600 hectares of land along the R??os Agrio and Guadiamar with approximately 5.5 million m3 of acidic water and 1.3×106 m3 of heavy metal-bearing tailings. Most of the deposited tailings and approximately 4.7×106 m3 of

Karen A Hudson-Edwards; Mark G Macklin; Heather E Jamieson; Paul A Brewer; Tom J Coulthard; Andy J Howard; Jon N Turner

2003-01-01

38

Real time prediction approach for floods caused by failure of natural dams due to overtopping  

NASA Astrophysics Data System (ADS)

This paper presents a real time prediction approach for floods caused by failure of natural dams due to overtopping. The approach adopts the observed outflow data of the preceding failure process for calibrating a simulation model, and the calibrated model is then implemented to predict the remaining failure process and flood characteristics. A widely used parametric model of dam failure is adopted in consideration of practicability and computational simplicity. The problems raised by interrelation among the model parameters and impeding the model calibration are analytically identified, and a simple but effective solution method is proposed. The approach was examined through two idealized cases where there exist no model inadequacy and measurement errors. Its effectiveness of and applicability to predicting the peak discharge and the time to peak of various outflows were exhibited. The real world case of Tangjiashan Quake Lake in China was further analyzed. The outflow peak discharge and the time to peak were reasonably predicted with one and a half hours ahead, demonstrating its potential for practical applications. Multistage features of the breach growth in nature may lower its performance due to raising difficulties in the identification of reasonable predictions. Future work of improving the model adequacy and observation accuracy would enhance its applicability to natural environments.

Ma, Hongbo; Fu, Xudong

2012-01-01

39

Comparison of Failure Modes from Risk Assessment and Historical Data for Bureau of Reclamation Dams. Dam Safety Research Report.  

National Technical Information Service (NTIS)

In the summer of 1997, the Bureau of Reclamation Dam Safety Office funded a student summer sabbatical to review initial studies of Risk Analysis of various dams. Two major questions were addressed: (1) Are risk analyses producing consistent results from t...

J. Tatalovich

1997-01-01

40

Hydrology, geomorphology, and dam-break modeling of the July 15, 1982, Lawn Lake Dam and Cascade Lake Dam failures, Larimer County, Colorado  

USGS Publications Warehouse

On July 15, 1982, Lawn Lake Dam, a 26-foot-high earthfill irrigation dam built in 1903 in Rocky Mountain National Park, Colorado, failed, due to piping, releasing 674 acre-feet of water with a peak discharge of 18,000 cubic feet per second down the Roaring River. Three people were killed, and damages were estimated at $31 million. Cascade Lake Dam, downstream from Lawn Lake Dam, subsequently failed as a result of the flood, increasing the peak flow at this point from 7,210 cubic feet per second to 16,000 cubic feet per second. The flood wave took 3.28 hours to travel 12.5 miles to Lake Estes, where all the floodwater was stored. The channel of the Roaring River was scoured as much as 50 feet and widened 300 feet. An alluvial fan of 42.3 acres, containing 10 million cubic feet of material, was deposited at the mouth of the Roaring River, damming the Fall River and forming a 17-acre lake. Various methods were used to indirectly compute peak discharge, attenuation of flow, and flood traveltime. A version of the National Weather Service dam-break flood model was used to evaluate its performance on high-gradient streams, to provide supplemental hydrologic information, and to evaluate various scenarios of dam-break development. (USGS)

Jarrett, R. D.; Costa, J. E.

1984-01-01

41

Geochemistry of Mercury and other trace elements in fluvial tailings upstream of Daguerre Point Dam, Yuba River, California, August 2001  

USGS Publications Warehouse

This study was designed to characterize the particle-size distribution and the concentrations of total mercury (HgT), methylmercury (MeHg), and other constituents in sediments trapped behind Daguerre Point Dam, a 28-foot-high structure on the lower Yuba River in California. The results of the study will assist other agencies in evaluating potential environmental impacts from mobilization of sediments if Daguerre Point Dam is modified or removed to improve the passage of anadromous fish. Methylmercury is of particular concern owing to its toxicity and propensity to bioaccumulate. A limited amount of recent work on hydraulic and dredge tailings in other watersheds has indicated that mercury and MeHg concentrations may be elevated in the fine-grained fractions of placer mining debris, particularly clay and silt. Mercury associated with tailings from placer gold mines is a source of continued contamination in Sierra Nevada watersheds and downstream water bodies, including the Sacramento?San Joaquin Delta and the San Francisco Bay of northern California. Churn drilling was used to recover sediments and heavy minerals at 5-foot intervals from six locations upstream of Daguerre Point Dam. Maximum depth of penetration ranged from 17.5 to 35 feet below land surface, resulting in 31 discreet drilled intervals. Drilling in permeable, unconsolidated sediments below the streambed of the Yuba River released a significant volume of water along with the sediment, which complicated the sampling and characterization effort. Overflow of a silty fraction sampled at the drill site contained suspended sediment consisting predominantly of silt and clay, with HgT concentration ranging from 33 to 1,100 ng/g (nanogram per gram) dry weight. A sandy fraction, collected after sieving sediment through a 2-millimeter vibratory screen, contained from 14 to 82 percent sand and 1 to 29 percent silt plus clay, and had HgT concentrations ranging from 6.8 to 81 ng/g dry weight. A clay-silt fraction, sampled from material remaining in suspension after the sandy fraction settled for 15-20 minutes, contained mercury concentrations from 23 to 370 ng/g dry weight. Concentrations of MeHg were less than the detection limit (<0.001 ng/g dry weight) in 30 of 31 samples of the sandy fraction. In the suspended clay-silt fraction, MeHg was detected in 16 of 31 samples, in which it ranged in concentration from 0.04 (estimated) to 0.61 ng/g wet weight. Potential rates of mercury methylation and demethylation were evaluated in seven samples using radiotracer methods. Mercury methylation (MeHg production) potentials were generally low, ranging from less than 0.15 to about 1.6 ng/g/d (nanogram per gram of dry sediment per day). Mercury demethylation (MeHg degradation) potentials were moderately high, ranging from 1.0 to 2.2 ng/g/d. The ratio of methylation potential (MP) to demethylation potential (DP) ranged from less than 0.14 to about 1.4 (median = 0.24, mean = 0.44, number of samples = 7), suggesting that the potential for net production of MeHg in deep sediments is generally low. The MeHg production rates and MP/DP ratios were higher in the shallower interval in two of the three holes where two depth intervals were assessed, whereas the MeHg concentrations were higher in the shallower interval for all three holes. A similar spatial distribution was found for concentrations of solid-phase sulfide (measured as total reduced sulfur and likely representing iron-sulfide and iron-disulfide compounds), which were much higher in shallower samples (about 700 to about 2,100 nanomoles per gram, dry sediment) than in deeper samples (32 to 55 nanomoles per gram, dry sediment) in these three holes. If reduced sulfur compounds are oxidized to sulfate as a consequence of sediment disturbance, the activity of sulfate-reducing bacteria might be stimulated, causing a short-term increase in methylation of inorganic Hg(II) (divalent mercury). The extent of increased Hg(II)-methylation w

Hunerlach, Michael P.; Alpers, Charles N.; Marvin-DiPasquale, Mark; Taylor, howard E.; DeWild, John F.

2004-01-01

42

Assessment of Vegetation Establishment on Tailings Dam at an Iron Ore Mining Site of Suburban Beijing, China, 7 Years After Reclamation with Contrasting Site Treatment Methods  

NASA Astrophysics Data System (ADS)

Strip-mining operations greatly disturb soil, vegetation and landscape elements, causing many ecological and environmental problems. Establishment of vegetation is a critical step in achieving the goal of ecosystem restoration in mining areas. At the Shouyun Iron Ore Mine in suburban Beijing, China, we investigated selective vegetation and soil traits on a tailings dam 7 years after site treatments with three contrasting approaches: (1) soil covering (designated as SC), (2) application of a straw mat, known as "vegetation carpet", which contains prescribed plant seed mix and water retaining agent (designated as VC), on top of sand piles, and (3) combination of soil covering and application of vegetation carpet (designated as SC+VC). We found that after 7 years of reclamation, the SC+VC site had twice the number of plant species and greater biomass than the SC and VC sites, and that the VC site had a comparable plant abundance with the SC+VC site but much less biodiversity and plant coverage. The VC site did not differ with the SC site in the vegetation traits, albeit low soil fertility. It is suggested that application of vegetation carpet can be an alternative to introduction of topsoil for treatment of tailings dam with fine-structured substrate of ore sands. However, combination of topsoil treatment and application of vegetation carpet greatly increases vegetation coverage and plant biodiversity, and is therefore a much better approach for assisting vegetation establishment on the tailings dam of strip-mining operations. While application of vegetation carpet helps to stabilize the loose surface of fine-structured mine wastes and to introduce seed bank, introduction of fertile soil is necessary for supplying nutrients to plant growth in the efforts of ecosystem restoration of mining areas.

Yan, Demin; Zhao, Fangying; Sun, Osbert Jianxin

2013-09-01

43

Arsenic Concentrations in Soils Impacted by Dam Failure of Coal-Ash Pond in Zemianske Kostolany, Slovakia  

Microsoft Academic Search

In this study, the concentrations of arsenic were determined in the soils around old coal-ash pond. The soils in the study\\u000a area were severely contaminated with arsenic after dam failure of the coal-ash pond. The mean concentrations of arsenic in\\u000a soils collected from three sampling depths of 0–20, 20–40 and >40 cm were 173, 155 and 426 ?g\\/g, respectively, exceeding greatly\\u000a the

L’ubomír Jurkovi?; Edgar Hiller; Veronika Veselská; Katarína Pet’ková

2011-01-01

44

Formation and failure of volcanic debris dams in the Chakachatna River valley associated with eruptions of the Spurr volcanic complex, Alaska  

USGS Publications Warehouse

The formation of lahars and a debris avalanche during Holocene eruptions of the Spurr volcanic complex in south-central Alaska have led to the development of volcanic debris dams in the Chakachatna River valley. Debris dams composed of lahar and debris-avalanche deposits formed at least five times in the last 8000-10,000 years and most recently during eruptions of Crater Peak vent in 1953 and 1992. Water impounded by a large debris avalanche of early Holocene (?) age may have destabilized an upstream glacier-dammed lake causing a catastrophic flood on the Chakachatna River. A large alluvial fan just downstream of the debris-avalanche deposit is strewn with boulders and blocks and is probably the deposit generated by this flood. Application of a physically based dam-break model yields estimates of peak discharge (Qp) attained during failure of the debris-avalanche dam in the range 104 < Qp < 106 m3 s-1 for plausible breach erosion rates of 10-100 m h-1. Smaller, short-lived, lahar dams that formed during historical eruptions in 1953, and 1992, impounded smaller lakes in the upper Chakachatna River valley and peak flows attained during failure of these volcanic debris dams were in the range 103 < Qp < 104 m3 s-1 for plausible breach erosion rates. Volcanic debris dams have formed at other volcanoes in the Cook Inlet region, Aleutian arc, and Wrangell Mountains but apparently did not fail rapidly or result in large or catastrophic outflows. Steep valley topography and frequent eruptions at volcanoes in this region make for significant hazards associated with the formation and failure of volcanic debris dams. Published by Elsevier Science B.V.

Waythomas, C. F.

2001-01-01

45

A physically-based method for predicting peak discharge of floods caused by failure of natural and constructed earthen dams  

USGS Publications Warehouse

We analyse a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V.D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether < ??? 1 or < ??? 1. Theoretical predictions agree well with data from dam failures for which k could be reasonably estimated. The analysis provides a rapid and in many cases graphical way to estimate plausible values of Qp at the breach.We analyze a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V/D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether ?????1 or ?????1. Theoretical predictions agree well with data from dam failures for which k could be reasonably estimated. The analysis provides a rapid and in many cases graphical way to estimate plausible values of Qp at the breach.

Walder, J. S.; O'Connor, J. E.; Costa, J. E.

1997-01-01

46

A physically-based method for predicting peak discharge of floods caused by failure of natural and constructed earthen dams  

USGS Publications Warehouse

We analyse a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V/ D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether ?? > 1. Theoretical predictions agree well with data from dam failures for which k could be reasonably estimated. The analysis provides a rapid and in many cases graphical way to estimate plausible values of Qp at the breach.

Walder, J. S.

1997-01-01

47

Bioaccumulation of Heavy Metals in the Lizard Psammodromus algirus After a Tailing-Dam Collapse in Aznalcóllar (Southwest Spain)  

Microsoft Academic Search

Quantification of heavy metal concentrations in biota is a common technique that helps environmental managers measure the\\u000a level of pollutants circulating in ecosystems. Despite interest in heavy metals as indicators of localized pollution, few\\u000a studies have assessed these pollutants in reptiles. In 1998, the tailing pond of a pyrite mine near Aznalcóllar (southwestern\\u000a Spain), containing mud with high heavy metal

Rocío Márquez-Ferrando; Xavier Santos; Juan M. Pleguezuelos; Diego Ontiveros

2009-01-01

48

Dam Pass or Fail  

NSDL National Science Digital Library

Students conduct Internet research to investigate the purpose and current functioning status of some of the largest dams throughout the world. They investigate the success or failure of eight dams and complete a worksheet. While researching the dams, they also gain an understanding of the scale of these structures by recording and comparing their reservoir capacities. Students come to understand that dams, like all engineered structures, have a finite lifespan and require ongoing maintenance and evaluation for their usefulness.

Integrated Teaching And Learning Program

49

Probable hydrologic effects of a hypothetical failure of Mackay Dam on the Big Lost River Valley from Mackay, Idaho to the Idaho National Engineering Laboratory  

USGS Publications Warehouse

Mackay Dam is an irrigation reservoir on the Big Lost River, Idaho, approximately 7.2 kilometers northwest of Mackay, Idaho. Consequences of possible rupture of the dam have long concerned the residents of the river valley. The presence of reactors and of a management complex for nuclear wastes on the reservation of the Idaho National Engineering Laboratory (INEL), near the river , give additional cause for concern over the consequences of a rupture of Mackay Dam. The objective of this report is to calculate and route the flood wave resulting from the hypothetical failure of Mackay Dam downstream to the INEL. Both a full and a 50 percent partial breach of this dam are investigated. Two techniques are used to develop the dam-break model. The method of characteristics is used to propagate the shock wave after the dam fails. The linear implicit finite-difference solution is used to route the flood wave after the shock wave has dissipated. The time of travel of the flood wave, duration of flooding, and magnitude of the flood are determined for eight selected sites from Mackay Dam, Idaho, through the INEL diversion. At 4.2 kilometers above the INEL diversion, peak discharges of 1,550.2 and 1,275 cubic meters per second and peak flood elevations of 1,550.3 and 1,550.2 meters were calculated for the full and partial breach, respectively. Flood discharges and flood peaks were not compared for the area downstream of the diversion because of the lack of detailed flood plain geometry. (Kosco-USGS)

Druffel, Leroy; Stiltner, Gloria J.; Keefer, Thomas N.

1979-01-01

50

Bioaccumulation of heavy metals in the lizard Psammodromus algirus after a tailing-dam collapse in Aznalcóllar (Southwest Spain).  

PubMed

Quantification of heavy metal concentrations in biota is a common technique that helps environmental managers measure the level of pollutants circulating in ecosystems. Despite interest in heavy metals as indicators of localized pollution, few studies have assessed these pollutants in reptiles. In 1998, the tailing pond of a pyrite mine near Aznalcóllar (southwestern Spain), containing mud with high heavy metal concentrations, collapsed, releasing 6 million m(3) of toxic sludge into the Guadiamar Basin. Here we analyze heavy metal concentrations in the most common reptile in the area, the large psammodromus, Psammodromus algirus, a rather small lizard. We quantified levels of several elements (Hg, Sb, Cd, Cr, Tl, Sn, Ba, Cu, Pb, Sr, Mn, Rb, As, and Zn) in lizard tail clips collected in and around the affected area during the springs of 2005 and 2006. Samples were collected from two contaminated localities, one directly affected by the spill, and another adjacent to the tailing pond, but not covered by toxic mud. We also collected samples from a nonpolluted control site in the same basin. We found higher concentrations of As, Tl, Sn, Pb, Cd, and Cu in lizards from the affected area than in lizards from the control site, indicating the continued presence of heavy metal pollutants in the terrestrial food chain 8 years after the mine accident. We did not uncover sexual or annual differences in heavy metal concentrations, although concentrations increased with lizard size. We discuss how heavy metals moved across the food chain to lizards, despite intensive restoration efforts after the accident, and suggest that reptiles to be included in biomonitoring programs of heavy metals pollution in terrestrial habitats. PMID:18587604

Márquez-Ferrando, Rocío; Santos, Xavier; Pleguezuelos, Juan M; Ontiveros, Diego

2009-02-01

51

Northwest Montana Libby/Hungry Horse Dams Wildlife Mitigation; Columbian Sharp-Tailed Grouse, 1990-1991 Final Report.  

SciTech Connect

Distribution, habitat use and survival of transplanted Columbian sharp-tailed grouse in the Tobacco Plains, Montana were studied from April, 1990 to August, 1991. For transplant purposes, 12 grouse (5 female and 7 male) were trapped on dancing grounds near Douglas Lake, British Columbia, Canada during spring, 1990. In April, 1991, trapping of 4 female and 2 male grouse for transplant occurred on the Sand Creek Wildlife Management Area in southeast Idaho while 3 additional males were transplanted from Douglas Lake. Minimum annual survival of transplanted grouse in the Tobacco Plains is relatively high (47%). High survival is possibly due to 2 factors: (1) topography and habitat characteristics that discourage dispersal and (2) the presence of limited but relatively good habitat. Two of 18 radio-equipped grouse dispersed out of the study area, while 2 others survived in the area for over 590 days. A negative correlation in distances moved between consecutive relocations and length of survival was seen in radio-equipped grouse in this study. Data collected during this study showed the importance of habitat associated with the Dancing Prairie Preserve. Three of 5 females transplanted in 1990 attempted to nest after being released. Nesting and brood rearing sites were characterized by dense grass cover with an average effective height {ge}20 cm. Shrub cover was associated only with brood rearing sites. Overall habitat use by transplanted Columbian Sharp-tailed grouse showed an apparent avoidance of agricultural land and use of other habitat types in proportion to their availability.

Cope, Michael G. [Montana State Univ., Bozeman, MT (United States)]|[Montana Dept. of Fish, Wildlife and Parks, Kalispell, MT (United States)

1992-07-01

52

75 FR 62024 - Metal and Nonmetal Dams  

Federal Register 2010, 2011, 2012, 2013

...and 57 RIN 1219-AB70 Metal and Nonmetal Dams AGENCY: Mine Safety and Health Administration...construction, operation, and maintenance of safe dams which can assure miners are protected from the hazards of dam failures. DATES: The comment period...

2010-10-07

53

NRC (Nuclear Regulatory Commission) Inventory of Dams.  

National Technical Information Service (NTIS)

The NRC Inventory of Dams has been prepared as required by the charter of the NRC Dam Safety Officer. The inventory lists 51 dams associated with nuclear power plant sites and 14 uranium mill tailings dams (licensed by NRC) in the U.S. as of February 1, 1...

G. E. Lear O. O. Thompson

1983-01-01

54

Assessment of dam failure flood and a natural, high-magnitude flood in a hyperarid region using paleoflood hydrology, Nahal Ashalim catchment, Dead Sea, Israel  

Microsoft Academic Search

A dam failure flood in 1993 with a peak discharge of 600–700 m3 s?1 (volume of 0.5 × 106 m3) and a natural, rainfall-runoff flood with a peak discharge of 420 m3s?1 (volume of >2.0 × 106 m3) in 2004 in the Nahal Ashalim catchment (75 km2) in the hyperarid Dead Sea region were comparatively analyzed. The two floods, which

Noam Greenbaum

2007-01-01

55

Elevations and discharges produced by a simulated flood wave on the lower Sabine River, Louisiana and Texas, caused by a theoretical dam failure  

USGS Publications Warehouse

The Toledo Bend Reservoir is located on the lower Sabine River between Louisiana and Texas. Two mathematical models were coupled to calculate the flood wave that would result from the theoretical failure of 25 percent of Toledo Bend Dam and route the wave downstream to Orange, Tex. Computations assumed failure (1) at the peak of the 100-year flood when discharge of the Sabine River is 102,000 cubic feet per second and (2) when the average discharge is 10,000 cubic feet per second. Two techniques were used in the dam-break model. The method of characteristics was used to propagate the shock wave following dam failure. The linear implicit finite-difference solution was used to route the flood wave following shock wave dissipation. The magnitude of the flow was determined for Burkeville, Bon Wier, Ruliff, and Orange, Tex., along the lower Sabine River. For these sites, respectively, the following peak elevations were calculated: 119, 82, 31, and 13 feet for the 100-year flood and 110, 75, 27, and 9 feet for the average discharge. (Woodard-USGS)

Neely, Braxtel L; Stiltner, Gloria J.

1979-01-01

56

Small dams need better management  

NASA Astrophysics Data System (ADS)

Many small dams around the world are poorly maintained and represent a safety hazard, according to Pisaniello et al. Better oversight of small dams is needed, the authors argue. The researchers reviewed literature, conducted case studies in four states in Australia, and developed policy benchmarks and best practices for small-dam management. Small dams, often just several meters high and typically privately owned by individual farmers, have historically caused major damage when they fail. For instance, in China in 1975, 230,000 people died when two large dams failed because of the cumulative failure of 60 smaller upstream dams. In the United States, in 1977 the 8-meter-high Kelly Barnes Lake dam failed, killing 39 people. Many other small-dam failures around the world have resulted in casualties and severe ecological and economic damage.

Balcerak, Ernie

2012-03-01

57

Nonlinear Aeroelastic Behavior of Tail / Rudder Systems with Freeplay and Actuator Failure  

NASA Astrophysics Data System (ADS)

This thesis discusses the development of numerical simulations implemented in MATLAB and of an experimental tail/rudder model for the investigation of the effects of non-linearities on control surface flutter of a three-degree of freedom typical section airfoil. Non-linearities investigated include a structural non-linearity in the form of freeplay about the control surface hinge line as well as velocity-squared damping, simulating a failed actuator. The mathematical modeling, design, and testing of a prototype velocity-squared damper is also presented for use in the numerical simulations. In both cases, the describing function method has been used to predict the amplitudes of possible Limit-Cycle Oscillations (LCOs) in the rudder DOF. Response amplitudes and frequencies in the frequency domain, are shown to agree extremely well with results obtained in the time-domain via direct numerical integration of the equations of motion. Both stable and unstable limit-cycle behavior has been predicted, resulting in a detailed set of predictions for the response of the system below the flutter boundary.

Noble, Matthew

58

Revegetation of coarse taconite iron ore tailing using municipal solid waste compost  

Microsoft Academic Search

On Minnesota's Mesabi Iron Range, coarse taconite iron ore tailing is often used as the principal material in the construction of dams for large tailing impoundments. Mineland reclamation rules in Minnesota require that tailing dams be vegetated to control erosion for dam stability and safety. Coarse taconite iron ore tailing is characterized chemically by an alkaline pH, low organic matter

Michael R. Norland; David L. Veith

1995-01-01

59

Flood wave attenuation by a wetland following a beaver dam failure on a second order boreal stream  

Microsoft Academic Search

On June 8 1994, a beaver dam on Rocky Creek, a small stream in central Alberta, failed and released about 7500 m3 of water. The estimated peak of the resulting flood wave was 15 m3 s?1, which is 3.5 times the maximum discharge recorded for the creek over 23 years. The flood wave destroyed five hydrometric\\u000a stations, scoured some channel

Graham R. Hillman

1998-01-01

60

Debris flows from failures Neoglacial-age moraine dams in the Three Sisters and Mount Jefferson wilderness areas, Oregon  

USGS Publications Warehouse

The highest concentration of lakes dammed by Neoglacial moraines in the conterminous United States is in the Mount Jefferson and Three Sisters Wilderness Areas in central Oregon. Between 1930 and 1980, breakouts of these lakes have resulted in 11 debris flows. The settings and sequences of events leading to breaching and the downstream flow behavior of the resulting debris flows provide guidance on the likelihood and magnitude of future lake breakouts and debris flows.

O'Connor, J. E.; Hardison, J. H.; Costa, J. E.

2001-01-01

61

The 26 May 1982 breakout flows derived from failure of a volcanic dam at El Chicho??n, Chiapas, Mexico  

USGS Publications Warehouse

The eruptions of El Chicho??n between 28 March and 4 April 1982 produced a variety of pyroclastic deposits. The climactic phase, on 3 April at 07:35 (4 April at 01:35 GMT), destroyed the central andesitic dome and fed pyroclastic surges and flows that dammed nearby drainages, including the Magdalena River. By late April, a lake had formed, 4 km long and 300-400 m wide, containing a volume of 26 ?? 106 m3 of hot water. At 01:30 on 26 May, the pyroclastic dam was breached and surges of sediment and hot water soon inundated the town of Ostuaca??n, 10 km downstream. This hot flood was finally contained at Pen??itas Hydroelectric Dam, 35 km downstream, where one fatality occurred and three workers were badly scalded. Stratigraphic and sedimentologic evidence indicates that the rapidly draining lake initially discharged two debris flows, followed by five smaller debris flows and water surges. The main debris flows became diluted with distance, and by the time they reached Ostuaca??n, they merged into a single hyperconcentrated flow with a sediment concentration of ???30 vol%. Deposits from this hyperconcentrated flow were emplaced for 15 km, as far as the confluence with another river, the Mas-Pac, below which the flow was diluted to sediment-laden streamflow. The minimum volume of the breakout-flow deposits is estimated at 17 ?? 106 m3. From high-water marks, flow profiles, and simulations utilizing the DAMBRK code from the National Weather Service, we calculated a maximum peak discharge of 11,000 m3/s at the breach; this maximum peak discharge occurred 1 h after initial breaching. The calculations indicated that ???2 h were required to drain the lake.

Macias, J. L.; Capra, L.; Scott, K. M.; Espindola, J. M.; Garcia-Palomo, A.; Costa, J. E.

2004-01-01

62

Phosphorus deficiency is the major limiting factor for wheat on alluvium polluted by the copper mine pyrite tailings: a black box approach  

Microsoft Academic Search

Failures of tailings dams have degraded large areas of agricultural alluvial soils worldwide, and concomitant soil pollution\\u000a studies are abundant. Yet, the data on the actual effects of thereby imposed stresses on major crops are scarce. This work\\u000a analyses the effect of pyrite tailings from a copper mine, deposited over crop fields by long-term flooding, on wheat (Triticum aestivum L.)

Nina Nikolic; Ljiljana Kostic; Aleksandar Djordjevic; Miroslav Nikolic

2011-01-01

63

Dam Impacts  

NSDL National Science Digital Library

While the creation of a dam provides many benefits, it can have negative impacts on local ecosystems. Students learn about the major environmental impacts of dams and the engineering solutions used to address them.

Integrated Teaching And Learning Program

64

Dam Forces  

NSDL National Science Digital Library

Students learn how the force of water helps determine the size and shape of dams. They use clay to build models of four types of dams, and observe the force of the water against each type. They conclude by deciding which type of dam they, as Splash Engineering engineers, will design for Thirsty County.

Integrated Teaching And Learning Program And Laboratory

65

14. Credit PED. Downstream elevation, near completion, showing tail race ...  

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

14. Credit PED. Downstream elevation, near completion, showing tail race and trestle used to carry excavated rock and construction materials across tail race. Photo c. 1909. - Dam No. 4 Hydroelectric Plant, Potomac River, Martinsburg, Berkeley County, WV

66

106. DAM EARTH DIKE SUBMERSIBLE DAMS & DIKE ...  

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

106. DAM - EARTH DIKE - SUBMERSIBLE DAMS & DIKE CONN. AT MOVABLE DAM (ML-8-52/2-FS) March 1940 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

67

Hydroelectric Dams  

NSDL National Science Digital Library

Although hydroelectric power represents a relatively small portion of the world's energy resources, it is still an important commodity with great potential. To harness hydropower, civil engineers must design dams that convert the kinetic energy of water into electricity.The fundamentals of general-use dams are discussed on the home page of the US Society on Dams (1). Besides providing brief background information, there are a few examples of the benefits of dams to society. For a much more technical perspective, check out the Hydropower Program of the US Department of Energy (2). This site examines (among other things) research and development and turbine systems used in hydropower operations. There are several reports available for download, many of which deal with improved technology that minimizes environmental hazards. A good place for grade school students to learn about dams is at National Geographic's Geoguide Web site (3). On the main page, the user can learn about different stages of development in dam construction. A section for classroom and family activities suggests many fun, educational projects that are suitable for kindergarten through high school. The Hydroelectric Design Center (see #4 above for URL) is part of the Army Corps of Engineers. The center's home page has a lot of information about hydropower projects with which it is involved, as well as descriptions of processes and components of a hydropower plant. Possibly the most famous dam in North America is the Hoover Dam (5). History, articles, functional descriptions, pictures, and other media are on the Hoover Dam Web site. A sharp contrast to the glory of the Hoover Dam is the Three Gorges Dam project in China (6). If it is completed, it will be the biggest dam on Earth; however, environmental concerns plague the project with controversy. This Web site outlines the enormous scale of the project and explains the possible benefits and disastrous consequences that may result. The Three Gorges Dam is the subject of a great activity for middle school students at DiscoverySchool.com (7). The activity is set up as a detailed lesson plan that lets teachers introduce the problems and benefits of the dam; additionally, basic engineering concepts are discussed. Hydropower could mean more than just electricity for the Lao People's Democratic Republic, a small country in Indochina where poverty is widespread. The Nam Theun 2 hydroelectric project (8) could bring substantial revenues from exported electricity.

Leske, Cavin.

2002-01-01

68

Numerical modelling dam break analysis for water supply project  

NASA Astrophysics Data System (ADS)

Dam provides many benefits to the society, but it can also cause extensive damage to downstream area when it fails. Dam failure can cause extensive damage to properties and loss of human life due to short warning time available. In general, dam spillway was designed to drain the maximum discharge from the dam during the Probable Maximum Flood (PMF). The spillway is functioned to prevent the dam from failure due to overtopping, which can lead to the dam failure. Dam failure will result in large volume of water travelling at very high velocity to the downstream area of the dam. It can cause extensive property damage, destruction of important facilities, and significant loss of human life along the way. Due to the potential of high hazard it poses to the downstream area, a dam break analysis is considered very essential. This paper focuses into the dam failure analysis for Kahang Dam by prediction of breach flow hydrographs and generation of inundation map at downstream area. From the PMF scenario simulation, the maximum inflow is 525.12 m3/s and peak discharge from the dam during dam failure is 6188m3/s. The results are able to provide information for preparation of Emergency Response Plan (PMF), in which appropriate steps can be taken by relevant authorities to avoid significant loss of human lives.

Lariyah, M. S.; Vikneswaran, M.; Hidayah, B.; Muda, Z. C.; Thiruchelvam, S.; Abd Isham, A. K.; Rohani, H.

2013-06-01

69

Peak outflow from a breached embankment dam  

USGS Publications Warehouse

A relation for rapidly predicting the peak outflow rate from a breached embankment dam has been presented. The prediction equation is based on reliable data from 19 embankment dam failures and requires as input the volume of water in the reservoir at the time a breach begins to form, and the estimated height of the final breach. Peak outflow predicted by the equation can be used with simplified flood routing procedures to determine peak flows at locations downstream of a dam. Use of the prediction equation will improve the accuracy of rapid assessments of damage that would be caused by the flood resulting from an embankment dam failure.

Froehlich, David, C.

1989-01-01

70

Twin-tailed fail-over for fileservers maintaining full performance in the presence of a failure  

DOEpatents

A method for maintaining full performance of a file system in the presence of a failure is provided. The file system having N storage devices, where N is an integer greater than zero and N primary file servers where each file server is operatively connected to a corresponding storage device for accessing files therein. The file system further having a secondary file server operatively connected to at least one of the N storage devices. The method including: switching the connection of one of the N storage devices to the secondary file server upon a failure of one of the N primary file servers; and switching the connections of one or more of the remaining storage devices to a primary file server other than the failed file server as necessary so as to prevent a loss in performance and to provide each storage device with an operating file server.

Coteus, Paul W. (Yorktown Heights, NY); Gara, Alan G. (Mount Kisco, NY); Giampapa, Mark E. (Irvington, NY); Heidelberger, Philip (Cortlandt Manor, NY); Steinmacher-Burow, Burkhard D. (Mount Kisco, NY)

2008-02-12

71

107. DAM EARTH DIKE SUBMERSIBLE DAMS PLANS ...  

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

107. DAM - EARTH DIKE - SUBMERSIBLE DAMS - PLANS & SECTIONS (ML-8-52/3-FS) March 1940 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

72

Natural Debris Dams and Debris-Dam Lakes  

NSDL National Science Digital Library

This site contains information that will help students to realize that in addition to the direct risk from debris flows and debris avalanches, voluminous deposition of volcanic material in valleys commonly forms unstable natural dams by blocking preexisting drainages and that if the size and structural integrity of the blockage is insufficient to hold back the reservoir that will form, catastrophic failure of the dam will result. Such a hazardous situation may persist for months, years, or decades following an eruption. An example is given of Mount St. Helens, where the debris avalanche raised the level of Spirit Lake 64 meters and dammed its natural outlet even higher and lakes formed in the tributaries of Coldwater and Castle Creeks. In addition, the site has links to publications and reports documenting historical landslide dams from around the world.

73

Outbursts of landslide dammed lakes - mapping their potential across the Himalaya  

NASA Astrophysics Data System (ADS)

Lake formation as a result of river damming by landslides is frequently observed in the Himalayas. Historic records are riddled with sudden failures of debris dams that culminated in catastrophic outburst floods and debris flows with far-reaching devastating consequences for downstream communities and infrastructure. In addition, it has been argued that the formation of large orogens is tightly coupled with the damming of these lakes as they trap sediments and abate river incision. The severity of outburst floods of landslide dammed lakes is directly related to the impounded water volume and downstream channel morphology both of which are controlled by topography. Prime insights into the spatial patterns of hazards generated by landslide dammed lakes can thus be inferred from digital elevation models (DEMs) that are available at sufficient detail at even the remotest localities. Here we quantify from topographic constraints the physically possible size range of catastrophic outburst events at the mountain-belt scale. By manipulating digital topographic, climatic, and river discharge data we estimate to first order the potential peak discharge arising from failure of hypothetical dams occurring anywhere throughout the Himalayan drainage network. Thus modelled peak discharges encompass four to six orders of magnitude, with the most extreme events surpassing the largest documented monsoon floods by a factor of >100. For a range of pre-defined breach rates, the heavy-tailed size distribution of peak discharge stretches with increasing dam height. Our simulation predicts the highest peak discharge for dam breaks outside of the Higher Himalaya, i.e. along the margins of the Tibetan Plateau, and the large orogen-parallel rivers of the Sub-Himalaya. Many of the bedrock rivers slicing through the Higher Himalaya are simply too steep to allow for trapping large quantities of water behind natural dams. This regional consistent pattern underscores the notion that high transient stream power associated with episodic natural dam breaks may play a dominant role in enhancing fluvial bedrock incision in the Higher Himalayas. From a hazard management perspective our data provide a promising and proactive tool for rapidly assessing the likely impacts of outburst events anywhere in the Himalayas.

Schwanghart, Wolfgang; Blöthe, Jan; Andermann, Christoff; Korup, Oliver

2013-04-01

74

HEC-RAS DAM BREAK MODELING OF GWINNETT COUNTY'S NRCS FACILITIES  

Microsoft Academic Search

The potential flood risk caused by dam failure is often more severe and can behave very different to that of natural flooding events. The tragedy of dam failure is all too familiar to Georgia with the failure of the Kelly Barnes dam near Toccoa Georgia which resulted in 39 deaths in the early hours of November 6th 1977. Floodplain maps

Sam Crampton

75

Probabilistic Concept for Gravity Dam Analysis.  

National Technical Information Service (NTIS)

This report describes a probabilistic concept for evaluating the safety of concrete dams against sliding and overturning failures in terms of the various sources of uncertainty underlying the design parameters. This concept is used to compute the probabil...

J. D. Prendergast

1979-01-01

76

Performance Parameters for Theodore Roosevelt Dam.  

National Technical Information Service (NTIS)

This focused summary of the performance parameters evaluation for Theodore Roosevelt Dam provides a guide to understanding and a quick means for review of (1) the potential failure modes and (2) the most important aspects of visual inspection and instrume...

1997-01-01

77

Proceedings of Dam-Break Flood Routing Model Workshop Held in Bethesda, Maryland on October 18-20, 1977.  

National Technical Information Service (NTIS)

Contents: The dam-break wave and the bore collapse on a beach; Unsteady flow analysis of dam-break waves; Flood plain inundation caused by dam failure; Simplified routing through reservoir; Floods from breaching of dams; Unsteady flow modeling of dam-brea...

1977-01-01

78

New Mexico: Dam Rio Grande  

Microsoft Academic Search

Flowing from southwestern Colorado to the Gulf of Mexico is the Rio Grande. Pictured is a dam along the the major river. With a total length of 1,896 miles, there are a large number of dams along the Rio Grande. These include: Cochiti Dam, Elephant Butte Dam, Caballo Dam, Amistad Dam, Falcon Dam, Anzalduas Dam, and Retamal Dam.

Chet Smolski

1993-01-01

79

Factors affecting the failure of copper connectors brazed to copper bus bar segments on a 615-MVA hydroelectric generator at Grand Coulee Dam  

SciTech Connect

On March 21, 1986, the United States Bureau of Reclamation experienced a ground fault in the main parallel ring assembly of Unit G19 - a 615-MVA hydroelectric generator - at Grand Coulee Dam, Washington. Inspection of the unit revealed that the ground fault had been induced by fracture of one or more of the copper connectors used to join adjacent segments of one of the bus bars in the north half of the assembly. Various experimental techniques were used to detect and determine the presence of cracks, crack morphology, corrosion products, and material microstructure and/or embrittlement. The results of these inspections and recommendations are given. 7 refs., 27 figs.

Atteridge, D.G.; Klein, R.F.; Layne, R.; Anderson, W.E.; Correy, T.B.

1988-01-01

80

Historic mills and mill tailings as potential sources of contamination in and near the Humboldt River basin, northern Nevada. Chapter D.  

USGS Publications Warehouse

Reconnaissance field studies of 40 mining districts in and near the Humboldt River basin have identified 83 mills and associated tailings impoundments and several other kinds of mineral-processing facilities (smelters, mercury retorts, heap-leach pads) related to historic mining. The majority of the mills and tailings sites are not recorded in the literature. All tailings impoundments show evidence of substantial amounts of erosion. At least 11 tailings dams were breached by flood waters, carrying fluvial tailings 1 to 15 km down canyons and across alluvial fans. Most of the tailings sites are dry most of the year, but some are near streams. Tailings that are wet for part of the year do not appear to be reacting significantly with those waters because physical factors such as clay layers and hard-pan cement appear to limit permeability and release of metals to surface waters. The major impact of mill tailings on surface- water quality may be brief flushes of runoff during storm events that carry acid and metals released from soluble mineral crusts. Small ephemeral ponds and puddles that tend to collect in trenches and low areas on tailings impoundments tend to be acidic and extremely enriched in metals, in part through cycles of evaporation. Ponded water that is rich in salts and metals could be acutely toxic to unsuspecting animals. Rare extreme storms have the potential to cause catastrophic failure of tailings impoundments, carry away metals in stormwaters, and transport tailings as debris flows for 1 to 15 km. In most situations these stormwaters and transported tailings could impact wildlife but probably would impact few or no people or domes-tic water wells. Because all identified historic tailings sites are several kilometers or more from the Humboldt River and major tributaries, tailings probably have no measurable impact on water quality in the main stem of the Humboldt River.

Nash, J. Thomas; edited by Stillings, Lisa L.

2003-01-01

81

Enhancing the safety of tailings management facilities  

SciTech Connect

Unsafe tailings management facilities (TMFs) have caused serious accidents in Europe threatening human health/life and the environment. While advanced design, construction and management procedures are available, their implementation requires greater emphasis. An integrated research project funded by the European Union was carried out between 2002 and 2005 with the overall goal of improving the safety of TMFs (Sustainable Improvement in Safety of Tailings Facilities - TAILSAFE, http://www.tailsafe.com/). The objective of TAILSAFE was to develop and apply methods of parameter evaluation and measurement for the assessment and improvement of the safety state of tailings facilities, with particular attention to the stability of tailings dams and slurries, the special risks inherent when such materials include toxic or hazardous wastes, and authorization and management procedures for tailings facilities. Aspects of tailings facilities design, water management and slurry transport, non-destructive and minimally intrusive testing methods, monitoring and the application of sensors, intervention and remediation options were considered in TAILSAFE. A risk reduction framework (the TAILSAFE Parameter Framework) was established to contribute to the avoidance of catastrophic accidents and hazards from tailings facilities. Tailings from the mining and primary processing of metals, minerals and coal were included within the scope of TAILSAFE. The project focused on the avoidance of hazards by developing procedures and methods for investigating and improving the stability of tailings dams and tailings bodies.

Meggyes, T.; Niederleithinger, E.; Witt, K.J.; Csovari, M.; Kreft-Burman, K.; Engels, J.; McDonald, C.; Roehl, K.E. [BAM, Berlin (Germany). Federal Institute for Material Research & Testing

2008-07-01

82

Methodology for Risk Analysis of Dam Gates and Associated Operating Equipment Using Fault Tree Analysis.  

National Technical Information Service (NTIS)

With limited maintenance dedicated to aging dam spillway gate structures, there is an increased risk of gate inoperability and corresponding dam failure due to malfunction or inadequate design. This report summarizes research on methodologies to assist in...

R. C. Patev C. Putcha S. D. Foltz

2005-01-01

83

226Ra bioavailability to plants at the Urgeiriça uranium mill tailings site  

Microsoft Academic Search

Large amounts of solid wastes (tailings) resulting from the exploitation and treatment of uranium ore at the Urgeiriça mine (north of Portugal) have been accumulated in dams (tailing ponds). To reduce the dispersion of natural radionuclides into the environment, some dams were revegetated with eucalyptus (Eucalyptus globolus) and pines (Pinus pinea). Besides these plants, some shrubs (Cytisus spp.) are growing

M. J Madruga; A Brogueira; G Alberto; F Cardoso

2001-01-01

84

Correlation of serum IgG concentration in foals and refractometry index of the dam's pre- and post-parturient colostrums: an assessment for failure of passive transfer in foals.  

PubMed

The object of this study was to evaluate the usefulness of measuring the differences in the values of the serum total protein (DVSTP) concentration of foals and the refractometry index (DVRI) of the milk of dams before and after nursing of the colostrum for assessing failure of passive transfer (FPT) in foals. Serum samples from 31 foals were collected before the first nursing and other 1 to 6 times between 4 and 24 hr after birth. Paired colostrum and milk samples were collected from 14 of their dams at the same time. Serum samples were analyzed for IgG concentration using a single radial immunodiffusion (SRID) test (98 samples) and total protein concentration using a temperature-compensating refractometer (98 samples). Colostrum and milk samples were analyzed for refractometry index (RI) using a Brix refractometer (71 samples). DVSTP concentration and DVRI were significantly correlated with serum IgG concentration. The negative predictive values (NPVs) of DVSTP concentration for detecting serum IgG concentrations<400 mg/dl and<800 mg/dl were 98.2% and 91.3% when the cutoff value is set to 0.4 mg/dl and 0.8 mg/dl, respectively. Furthermore, the NPVs of DVRI for detecting serum IgG concentrations<400 mg/dl and<800 mg/dl were 97.3% and 96.3% when the cutoff value is set to 6% and 10%, respectively. The results suggest that measurement of DVRI is useful in assessing FPT as an initial "stall-side" screening test, because it is easy, inexpensive to perform and allows for rapid interpretation. PMID:22785030

Korosue, Kenji; Murase, Harutaka; Sato, Fumio; Ishimaru, Mutsuki; Kotoyori, Yasumitsu; Nambo, Yasuo

2012-11-01

85

National Program for Inspection of Non-Federal Dams. West Lake Dam (MA 00288), Connecticut River Basin, Sandisfield, Massachusetts. Phase 1 Inspection Report.  

National Technical Information Service (NTIS)

The dam is an earthfill embankment about 920 feet in length, and 25 feet in height and has a reinforced concrete principle spillway, The dam has been rated fair. It has a classification of intermediate size and high hazard. Failure of the dam would pose a...

1979-01-01

86

Experimental Research on the Dam-Break Mechanisms of the Jiadanwan Landslide Dam Triggered by the Wenchuan Earthquake in China  

PubMed Central

Dam breaks of landslide dams are always accompanied by large numbers of casualties, a large loss of property, and negative influences on the downstream ecology and environment. This study uses the Jiadanwan landslide dam, created by the Wenchuan earthquake, as a case study example. Several laboratory experiments are carried out to analyse the dam-break mechanism of the landslide dam. The different factors that impact the dam-break process include upstream flow, the boulder effect, dam size, and channel discharge. The development of the discharge channel and the failure of the landslide dam are monitored by digital video and still cameras. Experimental results show that the upstream inflow and the dam size are the main factors that impact the dam-break process. An excavated discharge channel, especially a trapezoidal discharge channel, has a positive effect on reducing peak flow. The depth of the discharge channel also has a significant impact on the dam-break process. The experimental results are significant for landslide dam management and flood disaster prevention and mitigation.

Xu, Fu-gang; Yang, Xing-guo; Hao, Ming-hui

2013-01-01

87

Are Dams Forever?  

NSDL National Science Digital Library

Students learn that dams do not last forever. Similar to other human-made structures, such as roads and bridges, dams require regular maintenance and have a finite lifespan. Many dams built during the 1930-70s, an era of intensive dam construction, have an expected life of 50-100 years. Due to inadequate maintenance and/or for environmental reasons, some of these dams will fail or be removed in the next 50 years. The engineers with Splash Engineering have an ethical obligation to remind Thirsty County of the maintenance and lifespan concerns associated with its dam.

Integrated Teaching And Learning Program And Laboratory

88

106. Photocopied August 1978. EXTENSION OF TAIL PIT WALLS, APRIL ...  

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

106. Photocopied August 1978. EXTENSION OF TAIL PIT WALLS, APRIL 28, 1917. THE TIMBERWORK IN THE FOREGROUND WAS USED AS A COMBINATION COFFER DAM AND FORM FOR POURING THE CONCRETE TAIL RACE WALL EXTENSION. IN THE BACKGROUND ALONG THE POWER HOUSE SEVERAL COMPLETED WALL EXTENSIONS CAN BE SEEN DIMLY. (787) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

89

Engineer a Dam  

NSDL National Science Digital Library

In this activity, learners explore the function and engineering of dams and how dams have many uses and solve many problems in the world. Learners work in teams to engineer their own dam structure in a water trough that has the ability to release water in a controlled manner, as might be used in irrigation. Learners present their plans, execute and test their dams, and reflect on the experience.

Ieee

2014-05-22

90

Animal Tails  

NSDL National Science Digital Library

Call it tail envy. With only a vestigial nub to show for ourselves, perhaps it's no wonder that animal tails capture our attention. The following Web sites present some of the more interesting tails to be found in the animal kingdom. The first Web site contains a recent article from Discovery News describing new findings that at least one species of scorpion produces two distinct types of tail venom, which have completely different effects on their victims (1). The next site from Singapore Zoological Gardens introduces the cebids (our New World monkey cousins), some of which have amazing prehensile tails that are used like a fifth limb (2). The rattlesnake is another famously-tailed creature, highlighted in the following site from the Arizona-Sonora Desert Museum (3). The site covers the main aspects of rattlesnake natural history, including a section on how the rattle forms. The Great Plains Nature Center in Wichita, Kansas, offers a Web page devoted to the beaver, including tail trivia and an audio clip of a resident beaver surprised in his den at the Kansas Wildlife Exhibit (4). Anyone who has witnessed the freakishly fascinating spectacle of a gecko leaving its tail behind to distract a would-be predator will appreciate this brief bio of the Tokay gecko, presented by ReptileCenter.com, the Herpetologist's Portal (5). Stacy's Wag'N'Train -- offering dog-training classes in San Jose, California -- provides this online guide to dog body language, which would have a very limited vocabulary without the tail (6). So, how did the peacock get its tail? It's a simple question that has driven zoologists crazy for over a century. The next Web site (7) contains an in-depth article on the subject from the Independent (London), offered through National Geographic News. And finally, the bizarre gulper eel -- able to tie its tail in several knots -- gets is own Web page on Pangea, the Web server for the Department of Educational Leadership and Technology at Southeastern Louisiana University (8). This deep-sea curiosity uses its bioluminescent tail tip to lure hapless prey into its impossibly gigantic mouth.

Sohmer, Rachel.

2003-01-01

91

Safety Goals for High-Hazard Dams: Are Dams Too Safe?  

NASA Astrophysics Data System (ADS)

The 1977 National Dam Inspection Program determined that many high-hazard dams in the United States were incapable of passing a probable maximum flood (PMF). Retrofitting these dams was estimated to cost at least $10 billion. Since the PMF is revised upward periodically, retrofit is a continual issue. But surviving a PMF is a more stringent safety criterion than preventing other sources of dam failure; in addition, it is more stringent than safety criteria for other structures with respect to wind, earthquakes, or storm surges. This higher safety goal has large social costs. We propose an alternative safety goal, separating property damage from possible loss of lives. For a proposed dam whose failure could cause large loss of life or property damage, a careful evaluation should be done as to whether the dam should be built. For dams that impose smaller hazards, property damage should be handled by an analysis based on expected values of annualized benefits and costs. An adjustment for scale could be used if the property damage were extremely large. Danger to lives should be handled by establishing programs to warn and evacuate people. Our proposal should (1) lead to less injury and death, (2) use society's limited resources more efficiently, and (3) put the determination of safety goals on a more scientific and sensible basis.

Lave, Lester B.; Resendiz-Carrillo, Daniel; McMichael, Francis C.

1990-07-01

92

Safety goals for high-hazard dams: Are dams too safe  

SciTech Connect

The 1977 National Dam Inspection Program determined that many high-hazard dams in the US were incapable of passing a probable maximum flood (PMF). Retrofitting these dams was estimated to cost at least $10 billion. Since the PMF is revised upward periodically, retrofit is a continual issue. But surviving a PMF is a more stringent safety criterion than preventing other sources of dam failure; in addition, it is more stringent than safety criteria for other structures with respect to wind, earthquakes, or storm surges. This higher safety goal has large social costs. The authors propose an alternative safety goal, separating property damage from possible loss of lives. For a proposed dam whose failure could cause large loss of life or property damage, a careful evaluation should be done as to whether the dam should be built. For dams that impose smaller hazards, property damage should be handled by an analysis based on expected values of annualized benefits and costs. An adjustment for scale could be used if the property damage were extremely large. Danger to lives should be handled by establishing programs to warn and evacuate people. The authors' proposal should (1) lead to less injury and death, (2) use society's limited resources more efficiently, and (3) put the determination of safety goals on a more scientific and sensible basis.

Lave, L.B.; Resendiz-Carrillo, D.; McMichael, F.C. (Carnegie-Mellon Univ., Pittsburgh, PA (USA))

1990-07-01

93

Tail planes  

NASA Technical Reports Server (NTRS)

This report presents methods by which the cells of large commercial airplanes may be reduced. The tail of large airplanes represent an area where considerable improvement in weight and size reduction can be attained.

Constantin, L

1926-01-01

94

Tail Buffeting  

NASA Technical Reports Server (NTRS)

An approximate theory of buffeting is here presented, based on the assumption of harmonic disturbing forces. Two cases of buffeting are considered: namely, for a tail angle of attack greater and less than the stalling angle, respectively. On the basis of the tests conducted and the results of foreign investigators, a general analysis is given of the nature of the forced vibrations the possible load limits on the tail, and the methods of elimination of buffeting.

Abdrashitov, G.

1943-01-01

95

EARTHEN & CONCRETE DAMS  

NSDL National Science Digital Library

Civil Engineers will work on a wide variety of projects. One area that they may specialize in is Earthen and Concrete Dams. As a civil drafter you may find yourself working on one of these massive projects. This instructional unit will give you a basic introduction to the many different types of dams and how they are constructed. Lets begin by introducing you to the basic terminology and design structures of a dam. The following link will help you in gaining a basic knowledge of these amazing structures. Learn About Dams Even though you now have a basic understanding of dams, you are still a long ways away from being an ...

Taylor, Professor D.

2005-11-17

96

A model of sturgeon distribution under a dam of a hydro-electric power plant  

Microsoft Academic Search

This article is dedicated to the question of passage of sturgeon through a dam of a hydro-electric power plant (HPP) during spawning migrations. A model of distribution of water velocity in the tail water of HPP was constructed. On the basis of this model a model of sturgeon distribution under a dam of HPP was created. The latter model was

V. I. Gertsev; V. V. Gertseva

1999-01-01

97

16. Parker Dam, only top fourth of dam visible, at ...  

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

16. Parker Dam, only top fourth of dam visible, at 320' high, Parker Dam is one of the highest in the world. Much of this height is because dam penetrates well below river bottom to fasten to bedrock. - Parker Dam, Spanning Colorado River between AZ & CA, Parker, La Paz County, AZ

98

Stability analysis of White Oak Dam  

SciTech Connect

White Oak Dam is located in the White Oak Creek watershed which provides the primary surface drainage for Oak Ridge National Laboratory. A stability analysis was made on the dam by Syed Ahmed in January 1994 which included an evaluation of the liquefaction potential of the embankment and foundation. This report evaluates the stability of the dam and includes comments on the report prepared by Ahmed. Slope stability analyses were performed on the dam and included cases for sudden drawdown, steady seepage, partial pool and earthquake. Results of the stability analyses indicate that the dam is stable and failure of the structure would not occur for the cases considered. The report prepared by Ahmed leads to the same conclusions as stated above. Review of the report finds that it is complete, well documented and conservative in its selection of soil parameters. The evaluation of the liquefaction potential is also complete and this report is in agreement with the findings that the dam and foundation are not susceptible to liquefaction.

NONE

1995-04-11

99

Combination of lung ultrasound (a comet-tail sign) and N-terminal pro-brain natriuretic peptide in differentiating acute heart failure from chronic obstructive pulmonary disease and asthma as cause of acute dyspnea in prehospital emergency setting  

PubMed Central

Introduction We studied the diagnostic accuracy of bedside lung ultrasound (the presence of a comet-tail sign), N-terminal pro-brain natriuretic peptide (NT-proBNP) and clinical assessment (according to the modified Boston criteria) in differentiating heart failure (HF)-related acute dyspnea from pulmonary (chronic obstructive pulmonary disease (COPD)/asthma)-related acute dyspnea in the prehospital setting. Methods Our prospective study was performed at the Center for Emergency Medicine, Maribor, Slovenia, between July 2007 and April 2010. Two groups of patients were compared: a HF-related acute dyspnea group (n = 129) and a pulmonary (asthma/COPD)-related acute dyspnea group (n = 89). All patients underwent lung ultrasound examinations, along with basic laboratory testing, rapid NT-proBNP testing and chest X-rays. Results The ultrasound comet-tail sign has 100% sensitivity, 95% specificity, 100% negative predictive value (NPV) and 96% positive predictive value (PPV) for the diagnosis of HF. NT-proBNP (cutoff point 1,000 pg/mL) has 92% sensitivity, 89% specificity, 86% NPV and 90% PPV. The Boston modified criteria have 85% sensitivity, 86% specificity, 80% NPV and 90% PPV. In comparing the three methods, we found significant differences between ultrasound sign and (1) NT-proBNP (P < 0.05) and (2) Boston modified criteria (P < 0.05). The combination of ultrasound sign and NT-proBNP has 100% sensitivity, 100% specificity, 100% NPV and 100% PPV. With the use of ultrasound, we can exclude HF in patients with pulmonary-related dyspnea who have positive NT-proBNP (> 1,000 pg/mL) and a history of HF. Conclusions An ultrasound comet-tail sign alone or in combination with NT-proBNP has high diagnostic accuracy in differentiating acute HF-related from COPD/asthma-related causes of acute dyspnea in the prehospital emergency setting. Trial registration ClinicalTrials.gov NCT01235182.

2011-01-01

100

9. Excavation work at Pleasant Dam (now called Waddell Dam). ...  

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

9. Excavation work at Pleasant Dam (now called Waddell Dam). Photographer unknown, July, 22, 1926. Source: Maricopa County Municipal Water Conservation District Number One (MWD). - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

101

Bearing capacity of desiccated tailings  

SciTech Connect

The development of matric suctions in soils contributes to their shear strength, resulting in an enhanced factor of safety against bearing-capacity failure. In this paper, matric suction profiles of desiccated mine tailings are predicted from a steady-state solution for evaporative conditions, and from an isothermal mathematical model that simulates liquid and vapor water flow through soils. The shear-strength envelope with respect to matric suction is established by testing reconstituted tailings samples in a modified triaxial cell, in which matric suction can be controlled. The contribution of matric suction to the shear strength is interpreted as an additional apparent cohesion for use in bearing-capacity calculations. Because of the nonlinearity of the shear-strength profile, a numerical method of analysis is adopted to predict the ultimate bearing capacity of the desiccated tailings. A subsequent decrease in bearing capacity following 2D water infiltration into a partially capped tailings deposit and accompanying suction loss is investigated.

Rassam, D.W.; Williams, D.J. [Univ. of Queensland, Brisbane, Queensland (Australia). Dept. of Civil Engineering] [Univ. of Queensland, Brisbane, Queensland (Australia). Dept. of Civil Engineering

1999-07-01

102

NEW ENGLAND DAMS  

EPA Science Inventory

With the National Dam Inspection Act (P.L. 92-367) of 1972, Congress authorized the U.S. Army Corps of Engineers (USACE) to inventory dams located in the United States. The Water Resources Development Act of 1986 (P.L 99-662) authorized USACE to maintain and periodically publish...

103

Dammed or Damned?  

ERIC Educational Resources Information Center

Summarizes issues raised at a workshop on "People and Dams" organized by the Society for Participatory Research in Asia. Objectives were to (1) understand problems created by dams for people, (2) consider forces affecting displaced populations and rehabilitation efforts, and (3) gain a perspective on popular education efforts among affected…

Hirsch, Philip

1988-01-01

104

Morris Dam Ballistic Range.  

National Technical Information Service (NTIS)

The Morris Dam Ballistic Range is located on a lake formed by Morris Dam on the San Gabriel River, about five miles north of Azusa, California. The range facilities are used in the acquisition and study of water entry data, underwater trajectory character...

1964-01-01

105

Risk assessment of patient handling with ambulance stretcher systems (ramp/(winch), easi-loader, tail-lift) using biomechanical failure criteria.  

PubMed

The research aims to carry out a detailed analysis of the loads applied by the ambulance workers when loading/unloading ambulance stretchers. The forces required of the ambulance workers for each system are measured using a load cell in a force handle arrangement. The process of loading and unloading is video recorded for all the systems to register the posture of the ambulance workers in different stages of the process. The postures and forces exerted by the ambulance workers are analyzed using biomechanical assessment software to examine if the work loads at any stage of the process are harmful. Kinetic analysis of each stretcher loading system is performed. Comparison of the kinetic analysis and measurements shows very close agreement for most of the cases. The force analysis results are evaluated against derived failure criteria. The evaluation is extended to a biomechanical failure analysis of the ambulance worker's lower back using 3DSSPP software developed at the Centre for Ergonomics at the University of Michigan. The critical tasks of each ambulance worker during the loading and unloading operations for each system are identified. Design recommendations are made to reduce the forces exerted based on loading requirements from the kinetic analysis. PMID:17064948

Cooper, G; Ghassemieh, E

2007-09-01

106

Simulating dam-breach flood scenarios of the Tangjiashan landslide dam induced by the Wenchuan Earthquake  

NASA Astrophysics Data System (ADS)

Floods from failures of landslide dams can pose a hazard to people and property downstream, which have to be rapidly assessed and mitigated in order to reduce the potential risk. The Tangjiashan landslide dam induced by the Mw = 7.9 2008 Wenchuan earthquake had impounded the largest lake in the earthquake affected area with an estimated volume of 3 × 108 m3, and the potential catastrophic dam breach posed a serious threat to more than 2.5 million people in downstream towns and Mianyang city, located 85 km downstream. Chinese authorities had to evacuate parts of the city until the Tangjiashan landslide dam was artificially breached by a spillway, and the lake was drained. We propose an integrated approach to simulate the dam-breach floods for a number of possible scenarios, to evaluate the severity of the threat to Mianyang city. Firstly, the physically-based BREACH model was applied to predict the flood hydrographs at the dam location, which were calibrated with observational data of the flood resulting from the artificial breaching. The output hydrographs from this model were inputted into the 1-D-2-D SOBEK hydrodynamic model to simulate the spatial variations in flood parameters. The simulated flood hydrograph, peak discharge and peak arrival time at the downstream towns fit the observations. Thus this approach is capable of providing reliable predictions for the decision makers to determine the mitigation plans. The sensitivity analysis of the BREACH model input parameters reveals that the average grain size, the unit weight and porosity of the dam materials are the most sensitive parameters. The variability of the dam material properties causes a large uncertainty in the estimation of the peak flood discharge and peak arrival time, but has little influence on the flood inundation area and flood depth downstream. The effect of cascading breaches of smaller dams downstream of the Tangjiashan dam was insignificant, due to their rather small volumes, which were only 2% of the volume of the Tangjiashan lake. The construction of the spillway was proven to have played a crucial role in reducing the dam-breach flood, because all the other natural breach scenarios would have caused the flooding of the downstream towns and parts of Mianyang city. However, in retrospect improvements on the spillway design and the evacuation planning would have been possible. The dam-break flood risk will be better controlled by reducing the spillway channel gradient and the porosity of the coating of the channel bottom. The experience and lessons we learned from the Tangjiashan case will contribute to improving the hazard mitigation and risk management planning of similar events in future.

Fan, X.; Tang, C. X.; van Westen, C. J.; Alkema, D.

2012-10-01

107

Hydraulics of embankment-dam breaching  

NASA Astrophysics Data System (ADS)

Constructed or natural earthen dams can pose hazards to downstream communities. Experiments to date on earthen-dam breaching have focused on dam geometries relevant to engineering practice. We have begun experiments with dam geometries more like those of natural dams. Water was impounded behind dams constructed at the downstream end of the USGS debris-flow flume. Dams were made of compacted, well-sorted, moist beach sand (D50=0.21 mm), 3.5 m from toe to toe, but varying in height from 0.5 to 1 m; the lower the dam, the smaller the reservoir volume and the broader the initially flat crest. Breaching was started by cutting a slot 30-40 mm wide and deep in the dam crest after filling the reservoir. Water level and pore pressure within the dam were monitored. Experiments were also recorded by an array of still- and video cameras above the flume and a submerged video camera pointed at the upstream dam face. Photogrammetric software was used to create DEMs from stereo pairs, and particle-image velocimetry was used to compute the surface-velocity field from the motion of tracers scattered on the water surface. As noted by others, breaching involves formation and migration of a knickpoint (or several). Once the knickpoint reaches the upstream dam face, it takes on an arcuate form whose continued migration we determined by measuring the onset of motion of colored markers on the dam face. The arcuate feature, which can be considered the head of the "breach channel", is nearly coincident with the transition from subcritical to supercritical flow; that is, it acts as a weir that hydraulically controls reservoir emptying. Photogenic slope failures farther downstream, although the morphologically dominant process at work, play no role at all in hydraulic control aside from rare instances in which they extend upstream so far as to perturb the weir, where the flow cross section is nearly self-similar through time. The domain downstream of the critical-flow section does influence the hydrograph in another way: the broader the initial dam crest, the longer the time before critical flow control is established. Flood duration is thus increased but peak discharge is decreased. Visual inspection and overhead videography reveal little turbidity in water pouring over the weir, implying that sediment there moves dominantly as bedload. Furthermore, underwater videography gives the overall impression that along the upstream dam face, erosion occurs without redeposition. Thus it would be a mistake to use empiricisms for equilibrium bedload transport to model erosion of the embankment. In mathematical terms, erosion rate cannot be backed out by calculating the divergence of transport rate; rather, transport rate should be regarded as the spatial integral of erosion rate. We use photogrammetry and motion of the colored markers to determine the erosion rate of the weir, and then infer shear stress at the weir by applying the van Rijn sediment-pickup function. Shear stress determined in this fashion is much less than what one calculates from the gradient of the energy head (an approach appropriate to steady flow). Shear stress inferred from the pickup-function calculation can serve as a constraint on computational fluid-dynamics models. Another constraint on such models, revealed by the underwater videography, is the upstream limit of sand movement, where bed shear stress equals the critical value for sand entrainment.

Walder, J. S.; Iverson, R. M.; Logan, M.; Godt, J. W.; Solovitz, S.

2012-12-01

108

Gypsum-karst problems in constructing dams in the USA  

USGS Publications Warehouse

Gypsum is a highly soluble rock and is dissolved readily to form caves, sinkholes, disappearing streams, and other karst features that typically are also present in limestones and dolomites. Gypsum karst is widespread in the USA and has caused problems at several sites where dams were built, or where dam construction was considered. Gypsum karst is present (at least locally) in most areas where gypsum crops out, or is less than 30-60 m below the land surface. These karst features can compromise on the ability of a dam to hold water in a reservoir, and can even cause collapse of a dam. Gypsum karst in the abutments or foundation of a dam can allow water to pass through, around, or under a dam, and solution channels can enlarge quickly, once water starts flowing through such a karst system. The common procedure for controlling gypsum karst beneath the dam is a deep cut-off trench, backfilled with impermeable material, or a close-spaced grout curtain that hopefully will fill all cavities. In Oklahoma, the proposed Upper Mangum Dam was abandoned before construction, because of extensive gypsum karst in the abutments and impoundment area. Catastrophic failure of the Quail Creek Dike in southwest Utah in 1989 was due to flow of water through an undetected karstified gypsum unit beneath the earth-fill embankment. The dike was rebuilt, at a cost of US $12 million, with construction of a cut-off trench 600 m long and 25 m deep. Other dams in the USA with severe gypsum-karst leakage problems in recent years are Horsetooth and Carter Lake Dams, in Colorado, and Anchor Dam, in Wyoming. ?? 2007 Springer-Verlag.

Johnson, K. S.

2008-01-01

109

Consolidation of Tailings.  

National Technical Information Service (NTIS)

The integrity of cover systems placed on tailings impoundments will be affected by the potential for differential settlement of the tailings surface. This report reviews the phenomenon of consolidation for saturated and unsaturated tailings. The effect of...

J. D. Nelson R. E. Wardell S. R. Abt W. P. Staub

1983-01-01

110

United States Society on Dams  

NSDL National Science Digital Library

The United States Society on Dams (USSD) is a professional organization that promotes the advancement of dam engineering and technology, and fosters public awareness of the importance of dams. The best feature on the society's home page is its excellent introduction to dams and their benefits. First, a short definition of a dam is given, and then some reasons for their construction are outlined with specific examples. There are many pictures of dams across the country, and most have explanations for their importance. Hydroelectric power as a renewable resource is discussed in detail. This Web site is a good learning resource for both kids and adults.

2002-01-01

111

The impact of the Aznalcóllar mine tailing spill on groundwater  

Microsoft Academic Search

As a consequence of a mine tailing dam collapse on the 25th April 1998, more than 4000 ha of the Guadiamar riverflat and farmlands were flooded by 4 hm3 of sulphide slurry. A number of open wells (12 of the 47 analysed) were also flooded and the water was contaminated. Before the spill, the groundwater in the aquifers was of

Marisol Manzano; Carlos Ayora; Cristina Domenech; Paloma Navarrete; Antonio Garralon; Maria-Jesús Turrero

1999-01-01

112

Dams and Intergovernmental Transfers  

NASA Astrophysics Data System (ADS)

Gainers and Losers are always associated with large scale hydrological infrastructure construction, such as dams, canals and water treatment facilities. Since most of these projects are public services and public goods, Some of these uneven impacts cannot fully be solved by markets. This paper tried to explore whether the governments are paying any effort to balance the uneven distributional impacts caused by dam construction or not. It showed that dam construction brought an average 2% decrease in per capita tax revenue in the upstream counties, a 30% increase in the dam-location counties and an insignificant increase in downstream counties. Similar distributional impacts were observed for other outcome variables. like rural income and agricultural crop yields, though the impacts differ across different crops. The paper also found some balancing efforts from inter-governmental transfers to reduce the unevenly distributed impacts caused by dam construction. However, overall the inter-governmental fiscal transfer efforts were not large enough to fully correct those uneven distributions, reflected from a 2% decrease of per capita GDP in upstream counties and increase of per capita GDP in local and downstream counties. This paper may shed some lights on the governmental considerations in the decision making process for large hydrological infrastructures.

Bao, X.

2012-12-01

113

Bearing capacity of desiccated tailings  

Microsoft Academic Search

The development of matric suctions in soils contributes to their shear strength, resulting in an enhanced factor of safety against bearing-capacity failure. In this paper, matric suction profiles of desiccated mine tailings are predicted from a steady-state solution for evaporative conditions, and from an isothermal mathematical model that simulates liquid and vapor water flow through soils. The shear-strength envelope with

Daud W. Rassam; David J. Williams

1999-01-01

114

Usoi Dam (Tajikistan) the highest landslide dam on the world  

NASA Astrophysics Data System (ADS)

Natural dams an integral part of the landscape formation. They are formed when the soil from slopes blocks the watercourse. The development of such dam may lead to two rare but desirable extreme outcomes: quick easing of the new dam and leakage of water accumulated behind it or stabilization of the dam and the establishment of a permanent outflow of water from the newly formed lake before it overflows the dam. All outcomes between these two extremes pose a threat commonly resulting in catastrophic floods causing massive damage to the flooded areas. The largest known dam of this kind, more than 500 m high and existing already 100 years, is the Usoi Dam in Tajikistan. The dam is located in the Amur Darya river basin.

Roje-Bonacci, Tanja

2014-05-01

115

7 CFR 1724.55 - Dam safety.  

Code of Federal Regulations, 2010 CFR

...publications regarding dam safety are available from...Planning Guidelines for Dams,âFEMA 64. (ii...Federal Guidelines for Earthquake Analysis and Design of Dams,âFEMA 65. (iii...94. (iv)âDam Safety: An Owner's...

2010-01-01

116

7 CFR 1724.55 - Dam safety.  

Code of Federal Regulations, 2010 CFR

...publications regarding dam safety are available from...Planning Guidelines for Dams,âFEMA 64. (ii...Federal Guidelines for Earthquake Analysis and Design of Dams,âFEMA 65. (iii...94. (iv)âDam Safety: An Owner's...

2009-01-01

117

12. DIABLO DAM: VIEW OF DIABLO DAM AND SEATTLE CITY ...  

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

12. DIABLO DAM: VIEW OF DIABLO DAM AND SEATTLE CITY LIGHT BOATHOUSE AS SEEN FROM THE ROSS RESORT BOAT LANDING NORTH SIDE OF DIABLO LAKE, 1989. - Skagit Power Development, Diablo Dam, On Skagit River, 6.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

118

11. DIABLO DAM: VIEW OF DIABLO DAM AS SEEN FROM ...  

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

11. DIABLO DAM: VIEW OF DIABLO DAM AS SEEN FROM NORTH SHORE BETWEEN THE INTAKE STRUCTURE AND SEATTLE CITY LIGHT BOAT DOCK AND SHOWING THE FORMER, 1989. - Skagit Power Development, Diablo Dam, On Skagit River, 6.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

119

Documented historical landslide dams from around the world  

USGS Publications Warehouse

This data compilation consists of dBase IV1 data files of the location, date, triggering mechanism, kind, size, failure time and mechanism, breach dimensions, subsequent controls, materials, and references for 463 historical landslide dams and associated natural reservoirs that have been recorded throughout the World. The data base presented in this report is a compilation of information on the characteristics of 463 landslide dams from around the World. It forms a basis on which to assess potential threats from existing landslide dams, or newly-formed landslide dams. The data base includes only landslide dams that have formed in historical times - that is, those formed during times when humans were able to record their occurrence, and the information transferred through various means of written and/or oral documentation. There have been far more prehistoric landslide dams about which relatively little is known. None of these is included in this data base. The focus on historical landslide dams allows insights into this natural process that will aid in understanding their role as a significant geologic process in recent Earth history.

Costa, John E.; Schuster, Robert L.

1991-01-01

120

An Investigation on the Characteristics of the Seismic Signals Induced by Overtopping Dam Breach  

NASA Astrophysics Data System (ADS)

Deep-seated landslide masses often block rivers and form landslide dams. Most landslide dams are prone to failure by overtopping water and may induce strong surge wave in the downstream. This study discussed the characteristics of dam break surge wave by experimental methods. We established an artificial dam on a creek in Nantou, Taiwan, for the large-scale dam breach test by overtopping. Flume tests in laboratory were also setup to observe the stability and erosion process of model dams. Accelerometers were used to record the vibrational signals induced by the overtopped water. The vibration signals induced by the surge wave were successfully captured. The velocity of the surge wave front was calculated using the time-frequency spectral magnitude obtained from Hilbert-Huang Transform (HHT). The frequency contents of the seismic signals of the surge waves were also analyzed. The erosion process and erosion rate and duration were discussed. The characteristics including frequency range, duration and corresponding processes, of the vibration signals from the artificial dam and flume tests were compared to the analyzed characteristics of the actual landslide dam breach event at Xiaolin, Kaohsiung occurred in 2009 (Feng, 2012).; An artificial dam on a creek in Nantou, Taiwan, for the large-scale dam breach test by overtopping. ; Opening after the large-scale dam breach test by overtopping.

Feng, Z.; Chen, S.; Kao, S.

2012-12-01

121

A Catalog of Italian Dams.  

National Technical Information Service (NTIS)

This handbook has been compiled with the aim to systematize the information on Italian dams in order to use it in the construction of dams in the USSR. The handbook includes information on 325 dams of height 20 m and more, constructed up to July 1, 1967. ...

V. A. Romanova

1971-01-01

122

Spectroscopy of MPS(3):DAMS(+) composite materials  

NASA Astrophysics Data System (ADS)

Composite materials are comprised of two separate components that are brought together to form a new material that exhibits unique properties not found in the individual components. The composite material studied in this work is a guest dye cation, (4-[4-(dimethylamino)-alpha-styrl]-1-methylpyridinium) or DAMS+, intercalated into an inorganic host lattice (MPS 3, where M = Cd2+ or Mn2+). MPS3 :DAMS+ exhibits high-efficiency second-harmonic generation (SHG), which is only observed when a material lacks a center of symmetry. There must be an organization of dye molecules upon intercalation to induce the noncentrosymmetry necessary for SHG. The formation of dye aggregates will be studied as a possible noncentrosymmetric arrangement. The intercalated materials (MPS3:DAMS+) exhibited spectral features of J-aggregates. These features included a sharp aggregate absorption and emission band, known as the J-band. There was a small Stokes shift (250 cm-1) between aggregate absorption and emission bands, and a red-shift between the J-band and isolated dye absorption band (3,700 cm-1). The low-energy tail of the emission J-band was theoretically modeled using the Urbach-Martienssen equation, while the high-energy states were fit to a Gaussian to determine aggregate disorder. Disorder was also modeled using a Monte-Carlo lineshape analysis program. From these theoretical models, the aggregate was found to be two-dimensional and weakly coupled. A variety of sample types were studied including intercalated powders and single crystals using absorbance, reflectance and emission spectroscopy. Reflectance spectra were directly compared with absorbance spectra using the Kramers-Kronig Transformation2 to determine that the surface aggregates and the interior aggregates were structurally similar. A new imaging microspectrophotometer was developed to investigate the topology of the composite materials. Kinetics of the intercalation front were studied and a layer-by-layer intercalation mechanism was developed. Surface studies using other materials indicated the polyanion nature of MPS3 :DAMS+ was essential for aggregation. Infrared microspectroscopy was used to determine the orientation of dye molecules on the surface of the large composite crystals. The DAMS+ in MPS 3:DAMS+ was shown to form two-dimensional brickwork aggregates with the molecules aligned "edge-on" on the surface and interior of the host lattice.

Holt, Jennifer Suzanne

123

Application of lead stable isotopes to the Guadiamar Aquifer study after the mine tailings spill in Aznalcóllar (SW Spain)  

Microsoft Academic Search

On 25 April 1998 the tailings dam of the Aznalcóllar mine burst, a great quantity of pyrite waste sludge and acid water was spilled reaching the vicinity of the Doñana National Park. In surface and ground water samples taken a week after dam breaking, metals, trace elements and Pb isotopic ratios ( 206Pb\\/ 207Pb and 208Pb\\/ 206Pb) were analysed. In

I. Fernández; M. Olías; J. C. Cerón; J. De la Rosa

2005-01-01

124

33 CFR 222.6 - National Program for Inspection of Non-Federal Dams.  

Code of Federal Regulations, 2012 CFR

...such as limestone, gypsum, salt, basalt, claystone...be based upon either time-history or response spectra techniques...the dam. 7.Construction History including diversion scheme...human life or property. d. History of previous failures or...

2012-07-01

125

33 CFR 222.6 - National Program for Inspection of Non-Federal Dams.  

Code of Federal Regulations, 2011 CFR

...such as limestone, gypsum, salt, basalt, claystone...be based upon either time-history or response spectra techniques...the dam. 7.Construction History including diversion scheme...human life or property. d. History of previous failures or...

2011-07-01

126

Methods for Estimating the Impact of Hypothetical Dam Break Floods  

Microsoft Academic Search

This paper presents a method for estimating the impact of floods resulting from dam failure. These methods were developed for implementation at the Pacific Disaster Center in Hawaii. A hydraulic model embedded in a Geographic Information System (GIS) is used to estimate the downstream attenuation of the flood. The model output is then integrated with a Digital Elevation Model in

Jene Michaud; Carl Johnson; Judy Iokepa; Jillian Marohnic

127

Geomorphic hazard assessment of landslide dams in South Westland, New Zealand: fundamental problems and approaches  

NASA Astrophysics Data System (ADS)

Quantitative assessments of landslide hazard usually employ empirical, heuristic, deterministic, or statistical methods to derive estimates of magnitude-frequency distributions of landsliding. The formation and failure of landslide dams are common geomorphic processes in mountain regions throughout the world, causing a series of consequential off-site hazards such as catastrophic outburst floods, debris flows, backwater ponding, up- and downstream aggradation, and channel instability. Conceptual and methodological problems of quantifying geomorphic hazard from landslide dams result from (a) aspects of defining "landslide-dam magnitude", (b) scaling effects, i.e. the geomorphic long-range and long-term implications of river blockage, and (c) paucity of empirical data. Geomorphic hazard from a landslide dam-break flood on the basis of conditional probabilities is being analysed for the alpine South Westland region of New Zealand, where formation and failure of landslide dams is frequent. Quantification of the annual probability of landsliding and subsequent dam formation in the area is limited by historical and only partially representative empirical data on slope instability. Since landslide-dam stability is a major control governing the potential of catastrophic outburst flooding, the ensuing hazard is best assessed on a recurring basis. GIS-based modelling of virtual landslide dams is a simple and cost-effective approach to approximate site-specific landslide dam and lake dimensions, reservoir infill times, and scaled magnitude of potential outburst floods. Although crude, these order-of-magnitude results provide information critical to natural hazard planning, mitigation, or emergency management decisions.

Korup, Oliver

2005-03-01

128

Risk Perception Analysis Related To Existing Dams In Italy  

NASA Astrophysics Data System (ADS)

In the first part of this work, the progress of Italian National Rules about dams design, construction and operation are presented to highlight the strong connection existing between the promulgation of new decrees, as a consequence of a dam accidents, and the necessity to prevent further loss of lives and goods downstream. Following the Gleno Dam failure (1923), a special Ministerial Committee wrote out the first Regulations and made the proposal to establish, within the High Council of Public Works, a special department that become soon the "Dam Service", with the tasks of control and supervision about construction and operation phases of the dams and their reservoirs. A different definition of tasks and the structure of Dam Service were provided in accordance with law n° 183/1989, which transferred all the technical services to the Office of the Prime Minister; the aim was to join the Dam Office with the Department for National Technical Services, with the objective of increasing the knowledge of the territory and promoting the study on flood propagation downstream in case of operations on bottom outlet or hypothetical dam-break. In fact, population living downstream is not ready to accept any amount of risk because has not a good knowledge of the efforts of experts involved in dam safety, both from the operators and from the safety Authority. So it's important to optimize all the activities usually performed in a dam safety program and improve the emergency planning as a response to people's primary needs and feeling about safety from Civil Protection Authority. In the second part of the work, a definition of risk is provided as the relationship existing between probability of occurrence and loss, setting out the range within to plan for prevention (risk mitigation), thanks to the qualitative assessment of the minimum safety level that is suited to assign funds to plan for Civil Protection (loss mitigation). The basic meaning of the reliability of a zoned earthfill dam is illustrated by defining the risk analysis during its construction and operation. A qualitative "Event Tree Analysis" makes clear with an example the probability of occurrence of the events triggered by an earthquake, and leads to a classification of the damage level. Finally, a System Dynamics (SD) approach is presented to investigate possibilities of a preventive planning in relationship to the risk, so that it's possible to establish shared procedures to achieve the correct management in any crisis phase. As a qualitative result of a SD application, figure 1 presents a flow-chart about a case study on the same dam so to illustrate the emergency planning in a step by step procedure according to the Regulations.

Solimene, Pellegrino

2013-04-01

129

226Ra bioavailability to plants at the Urgeiriça uranium mill tailings site.  

PubMed

Large amounts of solid wastes (tailings) resulting from the exploitation and treatment of uranium ore at the Urgeiriça mine (north of Portugal) have been accumulated in dams (tailing ponds). To reduce the dispersion of natural radionuclides into the environment, some dams were revegetated with eucalyptus (Eucalyptus globolus) and pines (Pinus pinea). Besides these plants, some shrubs (Cytisus spp.) are growing in some of the dams. The objective of this study is to determine the 226Ra bioavailability from uranium mill tailings by quantifying the total and available fraction of radium in the tailings and to estimate its transfer to plants growing on the tailing piles. Plant and tailing samples were randomly collected and the activity concentration of 226Ra in plants (aerial part and roots) and tailings was measured by gamma-spectrometry. The exchangeable fraction of radium in tailings was quantified using one single step extraction with 1 mol dm-3 ammonium acetate (pH = 7) or 1 mol dm-3 calcium chloride solutions. The results obtained for 226Ra uptake by plants show that 226Ra concentration ratios for eucalyptus and pines decrease at low 226Ra concentrations in the tailings and appear relatively constant at higher radium concentrations. For shrubs, the concentration ratios increase at higher 226Ra solid waste concentrations approaching a saturation value. Percentage values of 16.0 +/- 8.3 and 12.9 +/- 8.9, for the fraction of radium extracted from the tailings, using 1 mol dm-3 ammonium acetate or calcium chloride solutions, respectively, were obtained. The 226Ra concentration ratios determined on the basis of exchangeable radium are one order of magnitude higher than those based on total radium. It can be concluded that, at a 95% confidence level, more consistent 226Ra concentration ratios were obtained when calculated on the basis of available radium than when total radium was considered, for all the dams. PMID:11379070

Madruga, M J; Brogueira, A; Alberto, G; Cardoso, F

2001-01-01

130

Uranium Mill Tailings Management  

SciTech Connect

This book presents the papers given at the Fifth Symposium on Uranium Mill Tailings Management. Advances made with regard to uranium mill tailings management, environmental effects, regulations, and reclamation are reviewed. Topics considered include tailings management and design (e.g., the Uranium Mill Tailings Remedial Action Project, environmental standards for uranium mill tailings disposal), surface stabilization (e.g., the long-term stability of tailings, long-term rock durability), radiological aspects (e.g. the radioactive composition of airborne particulates), contaminant migration (e.g., chemical transport beneath a uranium mill tailings pile, the interaction of acidic leachate with soils), radon control and covers (e.g., radon emanation characteristics, designing surface covers for inactive uranium mill tailings), and seepage and liners (e.g., hydrologic observations, liner requirements).

Nelson, J.D.

1982-01-01

131

Child with a Tail  

PubMed Central

Spina Bifida occulta usually presents with some cutaneous stigmata e.g. hair patch, sinus, lipoma, hyperpigmented skin and very rarely a congenital tail. A congenital tail may and may not be associated with spina bifida occulta and tethered cord. A four month old male child presented with congenital tail which was associated with spinal dysraphism and caused tethering of the cord itself. The tail and tethering lesion were excised successfully.

Sandhu, Asif Iqbal; Khan, Feeroz Alam; Ehmed, Ejaz; Dar, Sajid Hameed

2013-01-01

132

Length of Magnetospheric Tail  

Microsoft Academic Search

It is shown that hydromagnetic waves, through the action of radiation pressure, can prevent the tail of the magnetosphere from closing near the earth. It is argued that the tail of the magnetosphere may be 20 to 50 AU long. The tail can close at such heliocentric distances in the charge-exchange boundary shell where the solar wind is terminated and

A. J. Dessler

1964-01-01

133

Geomorphic and Ecological Issues in Removal of Sediment-Filled Dams in the California Coast Ranges (Invited)  

NASA Astrophysics Data System (ADS)

Water-supply reservoirs in the actively eroding California Coast Ranges are vulnerable to sediment filling, thus creating obsolete impounding dams (Minear & Kondolf 2009). Once full of sediment, there is more impetus to remove dams for public safety and fish passage, but managing accumulated sediments becomes a dominant issue in dam removal planning. We analyzed the planning process and sediment management analyses for five dams, all of which have important ecological resources but whose dam removal options are constrained by potential impacts to downstream urban populations. Ringe Dam on Malibu Ck, Matilija Dam on the Ventura River, Searsville Dam on San Francisquito Ck, and Upper York Creek Dam on York Ck cut off important habitat for anadromous steelhead trout (Oncorhynchus mykiss). San Clemente Dam on the Carmel River has a working fish ladder, but only some of the migratory steelhead use it. By virtue of having filled with sediment, all five dams are at greater risk of seismic failure. San Clemente Dam is at greater risk because its foundation is on alluvium (not bedrock), and the poor-quality concrete in Matilija Dam is deteriorating from an akali-aggregate reaction. Simply removing the dams and allowing accumulated sediments to be transported downstream is not an option because all these rivers have extremely expensive houses along downstream banks and floodplains, so that allowing the downstream channel to aggrade with dam-dervied sediments could expose agencies to liability for future flood losses. Analyses of potential sediment transport have been based mostly on application of tractive force models, and have supported management responses ranging from in-situ stabilization (San Clemente and Matilija) to removal of stored sediment (York) to annual dredging to maintain capacity and prevent sediment passing over the dam (proposed for Searsville).

Kondolf, G. M.; Oreilly, C.

2010-12-01

134

Simulation on particle crushing of tailings material under high pressure  

NASA Astrophysics Data System (ADS)

With continuous increase of the high tailings dam, it has an important practical and theoretical significance to study the mechanical characteristics of the tailings material under high pressures. It is indicated that strength envelopes of the tailings material have a remarkable nonlinear characteristics through the triaxial test under high pressures. A further study stated that the particle crushing has a critical effect on the mechanical behavior of the tailings material. In order to quantitatively research its influence, the grain size distribution of the tailings material is analyzed for pre-and post-test and the particle crushing of the tailings material is measured. The particle flow code is employed to simulate and monitor the sample during testing. Firstly, a model which considers the particle crushing is built under the plane strain condition. Then, a series of biaxial numerical tests of the tailings specimen are simulated by using the model. It is found that the simulation result agrees with the triaxial test. Finally, a law between the particle crushing and strain of the tailings material under different confining pressures is obtained.

Liu, Hai-ming; Liu, Yi-ming; Yang, Chun-he; Cao, Jing

2013-06-01

135

Detailing the human tail.  

PubMed

There have been 23 true vestigial tails reported in the literature since 1884. A new case is described, and its magnetic resonance imaging and pathological features are presented. A review of the literature and analysis of the pathological characteristics reveal that the vestigial human tail may be associated with other abnormalities. Vestigial tails contain adipose and connective tissue, blood vessels, and nerves and are covered by skin. Bone, cartilage, notochord, and spinal cord elements are lacking. Tails are easily removed surgically without residual effects. Since 29% (7 of 24) of the reported tails have been associated with other malformations, careful clinical evaluation of these patients is recommended. PMID:3284435

Dubrow, T J; Wackym, P A; Lesavoy, M A

1988-04-01

136

Experimental Study of Overtopping Induced Landslide Dam Break Flow and Two Layer Two Phase Mixture Model  

NASA Astrophysics Data System (ADS)

A series of experiments were conducted to investigate flood flow generated by the failure of landslide dams due to overtopping. These experiments aim to quantify the influences of inflow discharge, downstream slope, width of dam crest, dam height, and dam material on the flood flow. Images from high-speed cameras are used to determine the profiles of dam body and flow discharge during the failure processes. Results showed that the water level in the upstream reservoir and the erosion of dam body are the dominant factors affecting the downstream flood flow. A physical-based model is established to calculate the arriving time and the peak discharge of dam break flow using two phase mixture model. Both analytical and numerical solutions were derived for the model. The modelling results were verified using data from this and several other laboratory experimental datasets. The agreement between the calculated and measured data showed the applicability of the proposed model for predicting the peak discharge of overtopping induced dam break flow.

Liu, L.; Duan, J. G.; Zhong, D.; Zhang, H.

2013-12-01

137

Simulation of Soil Moisture Development in Flood Protecting Earth Dams  

NASA Astrophysics Data System (ADS)

Extreme floods represent an increased risk for urban areas and agriculture. Time to time the protective earth dams are destroyed by a suddenly increased amount of water with destroing or even cathastrophic consequences. A numerical study of the soil moisture development within the earth body during the flood is simulated under a selection of boundary conditions. Several soil materials are considered. Simulations are performed firstly for homogeneous materials using the 2D single domain approach, in the second step the dual permeability simulations are done assuming inhomogeneities in the construction which may lead to the preferential flow. Results for saturated as well as for unsaturated part of the dam are analyzed. Using the appropriate simulation model may help to design safer flood dams and evaluate the reason of possible failures to prevent future disasters. The research has been performed in the frame of research project VZ 04 CEZ MSM 6840770005.

Cislerova, M.; Zumr, D.; Dusek, J.; Vogel, T.

2007-12-01

138

Health impacts of large dams  

Microsoft Academic Search

Large dams have been criticized because of their negative environmental and social impacts. Public health interest largely has focused on vector-borne diseases, such as schistosomiasis, associated with reservoirs and irrigation projects. Large dams also influence health through changes in water and food security, increases in communicable diseases, and the social disruption caused by construction and involuntary resettlement. Communities living in

Leonard B Lerer; Thayer Scudder

1999-01-01

139

Why Do We Build Dams?  

NSDL National Science Digital Library

Students are introduced to the concept of a dam and its potential benefits, which include water supply, electricity generation, flood control, recreation and irrigation. This lesson begins an ongoing classroom scenario in which student engineering teams working for the Splash Engineering firm design dams for a fictitious client, Thirsty County.

Integrated Teaching And Learning Program

140

Steam generator nozzle dam system  

Microsoft Academic Search

Many utilities are utilizing steam generator nozzle dams inside their steam generators to permit refueling and eddy-current testing or repair of steam generator tubes to occur simultaneously. Prior to consideration of this application, steam generator nozzles did not have any means to positively hold such dams in place. However, some of the current steam generator nozzles are supplied with flange

1985-01-01

141

6. GENE WASH DAM, LOOKING NORTHWEST. SURVEY REFLECTOR IN FOREGROUND ...  

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

6. GENE WASH DAM, LOOKING NORTHWEST. SURVEY REFLECTOR IN FOREGROUND FOR MONITORING MOVEMENT OF DAM AND EARTH. - Gene Wash Reservoir & Dam, 2 miles west of Parker Dam, Parker Dam, San Bernardino County, CA

142

Three Dams in Central Arizona: A Study in Technological Diversity.  

National Technical Information Service (NTIS)

Three important dams in central Arizona will be used to illustrate relevant issues of dam technology in the United States. These three structures - Roosevelt Dam (completed in 1911), Stewart Mountain Dam (1930), and Horseshoe Dam (1946) - Were built under...

D. C. Jackson C. B. Fraser

1992-01-01

143

Inspection of earthen embankment dams using time lapse electrical resistivity tomography  

NASA Astrophysics Data System (ADS)

According to the National Inventory of Dams (NID), the number of dams across the United States is approximately 85,000. Many of these dams are more than 50 years old and need vast attention to ensure their safety. It is difficult to obtain a full assessment of the dam just by visual inspections alone. This is because many problems associated with dam failure occur internally, which makes it difficult to be observed by the dam inspectors. Examples of these flaws are piping and seepage (flow of water through or around dam walls). It is in this area where geophysical methods can aid in obtaining a more confident evaluation of a dam's integrity. Electrical resistivity is one geophysical technique that would be useful in detecting internal flaws associated with seepage and piping because it is sensitive to moisture changes. A study is being conducted to examine the feasibility of electrical resistivity tomography (ERT) to map and monitor internal compromised zones within earthen embankment dams. Two quarter-scaled earthen embankment dams were built at the United States Department of Agriculture (USDA) Agriculture Research Service (ARS) Hydraulics and Engineering Research Unit (HERU) in Stillwater, Oklahoma. These two dams were constructed with known internal compromised zones that are susceptible to seepage and piping. Electrical resistivity surveys were conducted on the completed dams using a 56 electrode dipole-dipole array. The collected data was then processed using electrical resistivity tomography (ERT) imaging software and evidence of these two compromised zones was easily visible. Also, additional surveys were conducted in order to monitor the changes in electrical signatures associated with changes in these zones due to filling of the reservoir and environmental/climate changes.

Case, Jared S.

144

Tails of Bacterial Motility  

NASA Astrophysics Data System (ADS)

The cytoplasm of living cells provides a complex fluid environment in which intracellular bacteria live and move. By analyzing the easily visible curved actin ``comet-tail'' of polymerization-based-motility bacteria such as Listeria monocytogenes, we can learn about sub-micron structure and dynamics of the tail and of the bacterial surface enzyme that catalyzes tail formation. By characterizing the motility, we can transform such motile systems into probes of the cytoplasmic environment.

Rutenberg, Andrew; Grant, Martin

2001-03-01

145

Theseus Tail Being Unloaded  

NASA Technical Reports Server (NTRS)

The tail of the Theseus prototype research aircraft is seen here being unloaded at NASA's Dryden Flight Research Center, Edwards, California, in May of 1996. The Theseus aircraft, built and operated by Aurora Flight Sciences Corporation, Manassas, Virginia, was a unique aircraft flown at NASA's Dryden Flight Research Center, Edwards, California, under a cooperative agreement between NASA and Aurora. Dryden hosted the Theseus program, providing hangar space and range safety for flight testing. Aurora Flight Sciences was responsible for the actual flight testing, vehicle flight safety, and operation of the aircraft. The Theseus remotely piloted aircraft flew its maiden flight on May 24, 1996, at Dryden. During its sixth flight on November 12, 1996, Theseus experienced an in-flight structural failure that resulted in the loss of the aircraft. As of the beginning of the year 2000, Aurora had not rebuilt the aircraft. Theseus was built for NASA under an innovative, $4.9 million fixed-price contract by Aurora Flight Sciences Corporation and its partners, West Virginia University, Morgantown, West Virginia, and Fairmont State College, Fairmont, West Virginia. The twin-engine, unpiloted vehicle had a 140-foot wingspan, and was constructed largely of composite materials. Powered by two 80-horsepower, turbocharged piston engines that drove twin 9-foot-diameter propellers, Theseus was designed to fly autonomously at high altitudes, with takeoff and landing under the active control of a ground-based pilot in a ground control station 'cockpit.' With the potential ability to carry 700 pounds of science instruments to altitudes above 60,000 feet for durations of greater than 24 hours, Theseus was intended to support research in areas such as stratospheric ozone depletion and the atmospheric effects of future high-speed civil transport aircraft engines. Instruments carried aboard Theseus also would be able to validate satellite-based global environmental change measurements. Dryden's Project Manager was John Del Frate.

1996-01-01

146

Review of Tiber Dam--Raising of Dam and Dike.  

National Technical Information Service (NTIS)

The Division of Technical Review performs conceptual reviews of the design, construction, and initial operation of dams and major structures, including modifications to such structures. The purpose of this report is to summarize and document the technical...

1982-01-01

147

JAPANESE EXPERIENCES IN RESETTLEMENT FOR DAM CONSTRUCTION  

Microsoft Academic Search

Some modalities planned or implemented in Japan in the past may be applied for future dam construction projects in the developing world. For example, some innovative ideas were planned for the Numata Dam, the largest dam construction project ever considered in Japan. The major concern of the planned Numata Dam was the number of resettlers, which was then estimated to

MIKIYASU NAKAYAMA

148

Arsenic and heavy metals in native plants at tailings impoundments in Queretaro, Mexico  

NASA Astrophysics Data System (ADS)

Ten native plants species that grow in three tailings dams from Ag, Pb, Cu and Zn mine in Queretaro, Mexico were studied. Total concentrations in tailings were 183-14,660 mg/kg As, 45-308 mg/kg Cd, 327-1754 mg/kg Pb, 149-459 mg/kg Cu and 448-505 mg/kg Zn. In the three tailings dams, the solubility of these elements is low. Tailings in dam 1 are acid generating while tailings in dams 2 and 3 are not acid-generating potential. Plants species that accumulate arsenic and heavy metals was identified; Nicotina glauca generally presented the highest concentrations (92 mg/kg As, 106 mg/kg Cd, 189 mg/kg Pb, 95 mg/kg Cu and 1985 mg/kg Zn). Other species that accumulate these elements are Flaveria pubescens, Tecoma stans, Prosopis Sp, Casuarina Sp and Maurandia antirrhiniflora. Two species were found that accumulates a large amount of metals in the root, Cenchrus ciliaris and Opuntia lasiacantha. Concentrations in soils in which plants grow were 488-5990 mg/kg As, 5-129 mg/kg Cd, 169-3638 mg/kg Pb, 159-1254 mg/kg Cu and 1431-13,488 mg/kg Zn. The Accumulation Factor (AF) determined for plants was less than 1, with exception of N. glauca for Cd. The correlation between arsenic and heavy metals found in soils and plants was low. Knowledge of plant characteristics allows it use in planning the reforestation of tailings dams in controlled manner. This will reduce the risk of potentially toxic elements are integrated into the food chain of animal species.

Santos-Jallath, José; Castro-Rodríguez, Alejandrina; Huezo-Casillas, José; Torres-Bustillos, Luis

149

Seismic safety of earth dams: A probabilistic approach  

SciTech Connect

The evaluation of the potential for slope sliding and/or liquefaction failure of earthen dams subjected to earthquake loadings is most often based on deterministic procedures of both the excitation input and of the physical model. Such treatment provides answers in the form of either factor of safety values or a yes or no as to whether liquefaction will occur or not. Uncertainties in the physical properties of the soil in the embankment and the foundation layers underlying the dam are typically treated with parametric studies. Consideration of probabilities pertaining to the uncertainties of the earthquake and of the site characterization is expected to augment the prediction of failure potential by associating slope and liquefaction failure to generic properties of the earthquake and of the site characterization. In this study, the procedures for conditional slope failure/liquefaction probabilities are formulated based on a series of simulated deterministic analyses of a dam cross section . These synthetic earthquakes emanate from a 1-D stationary stochastic process of zero mean and an analytical form of power spectral density function. The response of the dam section is formed upon a dynamic finite element approach which provides the temporal variations of the stresses, strains and pore water pressure throughout the model. The constitutive response of the granular soil skeleton and its coupling with the fluid phase is formulated based on the Biot dynamic equations of motion with nonlinear terms compensated for into soil hysteretic damping. Lastly, a stochastic approach to liquefaction based on the transferring of the input motion statistics to the cross section is presented.

Simos, N.; Costantino, C.J.; Reich, M.

1994-08-01

150

CLEARWATER SUBBASIN, ID -- DAM LOCATIONS  

EPA Science Inventory

This map includes locations of dams in the Clearwater subbasin, Idaho. Source: US Army Corps of Engineers, BPA, and State Water Resource Departments from the Eastside Ecosystems Management Project. ...

151

Economic Analysis of Dam Decommissioning.  

National Technical Information Service (NTIS)

This report describes the typical range of direct implementation cost, other direct cost (lost benefits), and benefit components, along with potential measurement methodologies, associated with economic benefit-cost analyses of dam decommissioning.

J. L. Platt

2003-01-01

152

Performance of heterogeneous earthfill dams under earthquakes: optimal location of the impervious core  

NASA Astrophysics Data System (ADS)

Earthfill dams are man-made geostructures which may be especially damaged by seismic loadings, because the soil skeleton they are made of suffers remarkable modifications in its mechanical properties, as well as changes of pore water pressure and flow of this water inside their pores, when subjected to vibrations. The most extreme situation is the dam failure due to soil liquefaction. Coupled finite element numerical codes are a useful tool to assess the safety of these dams. In this paper the application of a fully coupled numerical model, previously developed and validated by the authors, to a set of theoretical cross sections of earthfill dams with impervious core, is presented. All these dams are same height and have the same volume of impervious material at the core. The influence of the core location inside the dam on its response against seismic loading is numerically explored. The dams are designed as strictly stable under static loads. As a result of this research, a design recommendation on the location of the impervious core is obtained for this type of earth dams, on the basis of the criteria of minor liquefaction risk, minor soil degradation during the earthquake and minor crest settlement.

López-Querol, S.; Moreta, P. J. M.

2008-01-01

153

Study of damage to a high concrete dam subjected to underwater shock waves  

NASA Astrophysics Data System (ADS)

To study the effect of a strong underwater shock wave on a concrete dam, this research aims to improve hammer impact methods in model tests. Six 1:200 scale models were designed and tested under distributed impact loads. A device was deployed for a direct measurement of the impact force at the upstream face of the dams. The model dam bases were anchored to prevent displacement. The experimental results indicate that the top part of the concrete dam is a weak zone, and the impact failure initiates with a fracture on the top of the dam. The peak value of impact stress increases when the second crack appears in the concrete dam from the upstream face to the downstream face. And, the level of the second crack in the dam body is lower as the peak value of impact stress increases. In this study, dynamic analysis was conducted by calculating the results to verify the effectiveness of a device to directly measure the impact force. This method may be used to approximately forecast the damage of concrete dam and may also be useful in other engineering applications.

Lu, Lu; Li, Xin; Zhou, Jing

2014-06-01

154

WATER QUALITY AND METAL TRANSPORT IN WATER-COVERED MINE TAILINGS DEPOSITS AT SULPHIDE ORE MINES - IN SITU MEASUREMENTS AND MODELLING BY DGT SAMPLERS  

Microsoft Academic Search

This poster to Mine Water 2009, presents results from studies of metals in the surface layers of a mine tailing sediment from a water covered pyrite mine tailing dam in Norway. We used the Diffusive Gradients in Thin films (DGT) probe in parallell with Diffusive Equilbrium in Thin Films (DET) probe and a modified peeper to collect metals in porewater.

ODDVAR RØYSET; BIRGER BJERKENG; EIGIL IVERSEN; KARL JAN AANES

155

Human tails and pseudotails.  

PubMed

A case of a tail in a 2-week-old infant is reported, and findings from a review of 33 previously reported cases of true tails and pseudotails are summarized. The true, or persistent, vestigial tail of humans arises from the most distal remnant of the embryonic tail. It contains adipose and connective tissue, central bundles of striated muscle, blood vessels, and nerves and is covered by skin. Bone, cartilage, notochord, and spinal cord are lacking. The true tail arises by retention of structures found normally in fetal development. It may be as long as 13 cm, can move and contract, and occurs twice as often in males as in females. A true tail is easily removed surgically, without residual effects. It is rarely familial. Pseudotails are varied lesions having in common a lumbosacral protrusion and a superficial resemblance to persistent vestigial tails. The most frequent cause of a pseudotail in a series of ten cases obtained from the literature was an anomalous prolongation of the coccygeal vertebrae. Additional lesions included two lipomas, and one each of teratoma, chondromegaly , glioma, and a thin, elongated parasitic fetus. PMID:6373560

Dao, A H; Netsky, M G

1984-05-01

156

Management of uranium mill tailing: Geochemical processes and radiological risk assessment  

Microsoft Academic Search

This paper describes the geochemical processes regulating the mobilisation of heavy metals and radionuclides in the tailing dam of the uranium mining and milling facilities of Poços de Caldas, Brazil. The operational effluent release pollution of surface and groundwater was evaluated by means of monitoring data. The potential environmental impact after the future closure of the installation was assessed by

Horst M. Fernandes; Mariza R. Franklin; Lene H. S. Veiga; Patricia Freitas; Luis A. Gomiero

1996-01-01

157

Estimating tail probabilities  

SciTech Connect

This paper investigates procedures for univariate nonparametric estimation of tail probabilities. Extrapolated values for tail probabilities beyond the data are also obtained based on the shape of the density in the tail. Several estimators which use exponential weighting are described. These are compared in a Monte Carlo study to nonweighted estimators, to the empirical cdf, to an integrated kernel, to a Fourier series estimate, to a penalized likelihood estimate and a maximum likelihood estimate. Selected weighted estimators are shown to compare favorably to many of these standard estimators for the sampling distributions investigated.

Carr, D.B.; Tolley, H.D.

1982-12-01

158

Elwha River Riparian Vegetation Response to Dams and Dam Removal  

NASA Astrophysics Data System (ADS)

Riparian vegetation is highly diverse and influences habitat of aquatic and terrestrial wildlife. Riparian vegetation dynamics are driven by stream flow regime, and fluxes of sediment and large woody debris, all of which can be altered by river damming. Dam removal is often implemented, in part, to help restore degraded riparian vegetation by reversing the alteration of these key drivers. However, increased disturbance and sediment flux associated with transport and exposure of trapped reservoir sediment can complicate a simple return to pre-dam conditions and can favor exotic species. We are studying the effects of dams and their removal on riparian vegetation along the Elwha River in Washington State, where removal of two large dams began in September 2011. To characterize vegetation composition, structure, and diversity prior to dam removal, we sampled 60-150 vegetation plots in 2004, 2005, and 2010 along five cross-valley transects in each of three river reaches: above both dams (upper reach), between the dams (middle reach), and downstream of both dams (lower reach). In summer 2012, we resampled a subset of our plots in the lower and middle reaches to evaluate vegetation and geomorphic change. We also sampled vegetation, topography, and grain size along newly-established transects within the exposed former reservoir behind Elwha Dam, which was removed in 2011 and 2012. Plant community distribution on bottomland geomorphic surfaces along the Elwha is typical of other systems in the region. We identified 8 overstory and 26 understory communities using multivariate analyses. Young bar surfaces (5-20 yrs) were dominated by willow, red alder, and black cottonwood. Floodplains and transitional fluvial terraces (<90yrs) were generally dominated by alder and cottonwood. Mature terraces (>90yrs) were often dominated by big-leaf maple. Douglas fir occurred on both young and old floodplains and terraces. Overstory species composition was more stable from 2005 to 2010 than understory, understory species composition was more influenced by reach than overstory, and understory communities on younger landforms were less stable. From 2005 to 2010, there was a 26% increase in species richness in the lower reach but no significant changes elsewhere. In both 2005 and 2010 there was a significant decrease in native species richness (26% and 30% respectively) from the furthest upstream to furthest downstream reach. Exotic species richness was significantly higher in the downstream reach compared to the upstream reach in both years. Following dam removal, we documented different pioneer plant communities growing on different surfaces within the former reservoir behind Elwha Dam. Some surfaces were dominated by exotic species of concern to resource managers, such as Canada thistle and reed canarygrass, while others contained typical, native pioneer communities dominated by willow, alder, and cottonwood. Along our existing monitoring transects, we documented some sediment deposition on channel margins, bars and low floodplain surfaces, particularly in the lower reach; relatively little new deposition occurred in the more armored and stable middle reach. Future monitoring will reveal changes to existing vegetation communities and development of new communities in the former reservoirs as removal of the upstream dam is completed and millions of m3 of sediment are redistributed.

Shafroth, P. B.; Brown, R. L.; Clausen, A. J.; Chenoweth, J.

2012-12-01

159

Modelling Cometary Sodium Tails  

NASA Astrophysics Data System (ADS)

Neutral sodium is readily observed in cometary spectra and can be seen to form its own distinct tail around high activity comets. We present a brief overview of neutral sodium tail observations to date and discuss the importance of theoretical modelling in understanding these data. We have developed a new, 3D Monte-Carlo model of cometary sodium that incorporates several advancements over previous models. It includes weightings due to solar flux variation with heliocentric distance, and comprehensive handling of the Swings and Greenstein effects on the neutral sodium tail, which can have particularly dramatic effects in near-Sun comets. Some preliminary results from this model are presented, including predictions of the structure of the eagerly anticipated neutral sodium tail at Comet C/2012 S1 (ISON).

Birkett, K. S.; Jones, G. H.; Coates, A. J.

2013-09-01

160

Wagging tail vibration absorber  

NASA Technical Reports Server (NTRS)

A 750-foot cantilever length of extendible-tape boom (very low stiffness) was considered as the main system to be damped. A number of tail lengths were tried from 20 feet to 80 feet after which 40 feet was investigated further as a desirable compromise between performance and practical lengths. A 40-foot damping tail produced a damping effect on the main boom for the first mode equivalent in decay rate to 3.1 percent of critical damping. In this case the spring-hinge and tail were tuned to the main boom first mode frequency and the hinge damping was set at 30 percent of critical based on the tail properties. With this same setting, damping of the second mode was .4 percent and the third mode .1 percent.

Barclay, R. G.; Humphrey, P. W.

1969-01-01

161

Uranium Mill Tailings.  

National Technical Information Service (NTIS)

This bibliography contains information on uranium mill tailings included in the Department of Energy's Energy Data Base from January 1981 through October 1982. The abstracts are grouped by subject category as shown in the table of contents. Entries in the...

L. H. McLaren

1982-01-01

162

The Tail Suspension Test  

PubMed Central

The tail-suspension test is a mouse behavioral test useful in the screening of potential antidepressant drugs, and assessing of other manipulations that are expected to affect depression related behaviors. Mice are suspended by their tails with tape, in such a position that it cannot escape or hold on to nearby surfaces. During this test, typically six minutes in duration, the resulting escape oriented behaviors are quantified. The tail-suspension test is a valuable tool in drug discovery for high-throughput screening of prospective antidepressant compounds. Here, we describe the details required for implementation of this test with additional emphasis on potential problems that may occur and how to avoid them. We also offer a solution to the tail climbing behavior, a common problem that renders this test useless in some mouse strains, such as the widely used C57BL/6. Specifically, we prevent tail climbing behaviors by passing mouse tails through a small plastic cylinder prior to suspension. Finally, we detail how to manually score the behaviors that are manifested in this test.

Terrillion, Chantelle E.; Piantadosi, Sean C.; Bhat, Shambhu; Gould, Todd D.

2012-01-01

163

17. VIEW OF MAIN AND DIVERSION DAMS FROM WATERGATE AFTER ...  

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

17. VIEW OF MAIN AND DIVERSION DAMS FROM WATER-GATE AFTER REMOVAL OF DRIFTWOOD. DIVERSION DAM IN LEFT FOREGROUND, MAIN DAM TO THE RIGHT. Photographed July 18, 1938. - Forge Creek Dam-John Cable Mill, Townsend, Blount County, TN

164

Beaver dams, hydrological thresholds, and controlled floods as a management tool in a desert riverine ecosystem, Bill Williams River, Arizona  

USGS Publications Warehouse

Beaver convert lotic stream habitat to lentic through dam construction, and the process is reversed when a flood or other event causes dam failure. We investigated both processes on a regulated Sonoran Desert stream, using the criterion that average current velocity is < 0.2 m s-1 in a lentic reach. We estimated temporal change in the lotic:lentic stream length ratio by relating beaver pond length (determined by the upstream lentic-lotic boundary position) to dam size, and coupling that to the dam-size frequency distribution and repeated censuses of dams along the 58-km river. The ratio fell from 19:1 when no beaver dams were present to < 3:1 after 7 years of flows favourable for beaver. We investigated the dam failure-flood intensity relationship in three independent trials (experimental floods) featuring peak discharge ranging from 37 to 65 m3 s-1. Major damage (breach ??? 3-m wide) occurred at ??? 20% of monitored dams (n = 7-86) and a similar or higher proportion was moderately damaged. We detected neither a relationship between dam size and damage level nor a flood discharge threshold for initiating major damage. Dam constituent materials appeared to control the probability of major damage at low (attenuated) flood magnitude. We conclude that environmental flows prescribed to sustain desert riparian forest will also reduce beaver-created lentic habitat in a non-linear manner determined by both beaver dam and flood attributes. Consideration of both desirable and undesirable consequences of ecological engineering by beaver is important when optimizing environmental flows to meet ecological and socioeconomic goals. ?? 2010 John Wiley & Sons, Ltd.

Andersen, D. C.; Shafroth, P. B.

2010-01-01

165

Three Gorges Dam, China  

NASA Technical Reports Server (NTRS)

This ASTER image shows a 60 km stretch of the Yangtze River in China, including the Xiling Gorge, the eastern of the three gorges. In the left part of the image is the construction site of the Three Gorges Dam, the world's largest.

This image was acquired on July 20, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

Size: 60 x 24 km (36 x 15 miles) Location: 30.6 deg. North lat., 111.2 deg. East long. Orientation: North at top Image Data: ASTER bands 1,2, and 3. Original Data Resolution: 15 m Date Acquired: July 20, 2000

2002-01-01

166

The Dramatic Methods of Hans van Dam.  

ERIC Educational Resources Information Center

Interprets for the American reader the untranslated dramatic methods of Hans van Dam, a leading drama theorist in the Netherlands. Discusses the functions of drama as a method, closed dramatic methods, open dramatic methods, and applying van Dam's methods. (SR)

van de Water, Manon

1994-01-01

167

The Best Dam Simulation Ever  

NSDL National Science Digital Library

This online simulation game explores the different consequences of water levels on the Columbia River in the Pacific Northwest. Learners play the role of dam operator, controlling how much water passes through the dam each season. First, learners choose whether it's a very dry or wet (or average) year and adjust the level of the reservoir in fall, winter, spring and summer. Learners see how their choices affect the migrating river salmon, power bills, recreation, agriculture, flooding, and fish that live in the reservoir. The results are compared to those of the real operators, and learners can print out a copy of your final report.

Omsi

2006-01-01

168

Should We Dam Nanticoke Creek?  

NSDL National Science Digital Library

In this decision-making exercise, students investigate what would occur if a dam were built along Nanticoke Creek, a real stream just north of West Corners near the Village of Endicott, New York. They will use topographic maps to determine how much area would be flooded by the new reservoir, to study river drainages, and to consider the impacts of dams on a region. They must also consider rivers in the context of their relation to humankind. The exercise can be extended to other, more local locations having similar topography.

Childs, Philip

169

33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.  

Code of Federal Regulations, 2013 CFR

...Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. 208...Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. ...objectives of the Marshall Ford Reservoir (Lake Travis) are the improvement of...

2013-07-01

170

Safety of Dams: Flood and Earthquake Criteria.  

National Technical Information Service (NTIS)

The Safety of Dams: Flood and Earthquake Criteria concerns the levels of safety to be provided at new and existing dams to withstand extreme floods and earthquakes. The report includes a thorough inventory of safety criteria for dams in use in the United ...

1985-01-01

171

Teton Dam flood of June 1976, Menan Buttes quadrangle, Idaho  

USGS Publications Warehouse

The failure of the Teton Dam caused extreme flooding along the Teton River, Henrys Fork, and Snake River in southeastern Idaho on June 5-8, 1976. No flooding occurred downstream from American Falls Reservoir. The inundated areas and maximum water-surface elevations are shown in a series of 17 hydrologic atlases. The area covered by the atlases extends from Teton Dam downstream to American Falls Reservoir, a distance of 100 miles. The extent of flooding shown on the maps was obtained by field inspections and aerial photographs made during and immediately after the flood. There may be small isolated areas within the boundaries shown that were not flooded, but the identification of these sites was beyond the scope of the study. The elevation data shown are mean-sea-level elevations of high-water marks identified in the field. This particular map (in the 17-map series) shows conditions in the Menan Buttes quadrangle. (Woodard-USGS)

Thomas, Cecil A.; Ray, Herman A.; Harenberg, William A.

1976-01-01

172

Altering Reservoir Withdrawal: a modeling approach to tail-water eutrophication on the South Fork Humboldt Reservoir, NV USA  

Microsoft Academic Search

The South Fork Humboldt Reservoir (south of Elko, Nevada) represents an arid, hypolimnetic release dam with tail-water eutrophication exceeding 300mg Chla per m2. The USEPA model AQUATOX 3 has been used to simulate reservoir nutrient loadings on tail-water periphyton and to predict changes in stream response to top release conditions. From April to September of 2009, an investigation characterized reservoir

D. W. Smith; J. J. Warwick; C. H. Fritsen; C. Davis; J. Memmott; E. Wirthlin

2010-01-01

173

Dam Safety and the Environment.  

National Technical Information Service (NTIS)

The volume is a compendium of papers presented at the Seminar on Dam Safety and the Environment held in Washington, D.C., in April 1989, and sponsored by the World Bank. The main objective of the seminar was to consolidate the experience of World Bank sta...

G. Le Moigne S. Barghouti H. Plusquellec

1990-01-01

174

Subdaily Hydrologic Variability by Dams  

NASA Astrophysics Data System (ADS)

The effects dams have on hydrologic, geomorphic, and ecologic regimes has been well characterized using mean daily discharge. Subdaily discharge variation (herein flashiness) has not been well characterized for a variety of dam, watershed, and land cover characteristics. The hourly hydrologic records for 30 sites across the continental United States were analyzed for flashiness using the Richards-Baker Index, coefficient of daily variation, percent of total flow variation, and the percent of the year when daily discharge is greater than mean daily discharge. The goal of this analysis is to evaluate the role of catchment variables such as mean slope and land use conditions across receiving watersheds in predicting flashiness; compare flashiness metrics across sites to identify relationships between dam related variables such as type and size; and determine the most appropriate temporal extent for assessing flashiness in streamflow. Our approach relies on data at the watershed scale with a fine temporal grain to determine flashiness over a decade of operation for each dam.

Costigan, K. H.; Ruffing, C.; Smith, J. M.; Daniels, M. D.

2012-12-01

175

Human tail: nature's aberration.  

PubMed

Human tail refers to a congenital cutaneous appendix protruding from the lumbosacral region. It is usually associated with an underlying spina bifida occulta, a form of spinal dysraphism. A contiguous fibrolipoma can sometimes be seen extending from the subcutaneous portion of the tail into the inferior spinal cord, resulting in tethered cord syndrome. Management of such lesions includes complete neurologic examination and magnetic resonance imaging. Early diagnosis and microsurgical intervention can prevent development or progression of severe neurologic defects in later life. PMID:22241711

Kumar, Dipti; Kapoor, Akshay

2012-07-01

176

The Dos Bocas dam in Puerto Rico.  

NSDL National Science Digital Library

The Dos Bocas dam in Puerto Rico was constructed in 1942 to generate hydroelectric power. Dams in this region prevent the migration of shrimp and fish to areas upstream of the dam. As a result, compared to similar reaches of undammed streams, areas that are upstream of dammed rivers have higher amounts of organic and inorganic nutrients as well as altered invertebrate populations. Loss of migratory shrimp and fish upstream from dams alters basal resources and assemblages of invertebrate competitors and prey. This photograph originally appeared on the cover of Ecological Applications (16:1) in February of 2006.

Klemow, Kenneth

2010-02-11

177

Multiple flow processes accompanying a dam-break flood in a small upland watershed, Centralia, Washington  

USGS Publications Warehouse

On October 5, 1991, following 35 consecutive days of dry weather, a 105-meter long, 37-meter wide, 5.2-meter deep concrete-lined watersupply reservoir on a hillside in the eastern edge of Centralia, Washington, suddenly failed, sending 13,250 cubic meters of water rushing down a small, steep tributary channel into the city. Two houses were destroyed, several others damaged, mud and debris were deposited in streets, on lawns, and in basements over four city blocks, and 400 people were evacuated. The cause of failure is believed to have been a sliding failure along a weak seam or joint in the siltstone bedrock beneath the reservoir, possibly triggered by increased seepage into the rock foundation through continued deterioration of concrete panel seams, and a slight rise (0.6 meters) in the pool elevation. A second adjacent reservoir containing 18,900 cubic meters of water also drained, but far more slowly, when a 41-cm diameter connecting pipe was broken by the landslide. The maximum discharge resulting from the dam-failure was about 71 cubic meters per second. A reconstructed hydrograph based on the known reservoir volume and calculated peak discharge indicates the flood duration was about 6.2 minutes. Sedimentologic evidence, high-water mark distribution, and landforms preserved in the valley floor indicate that the dam failure flood consisted of two flow phases: an initial debris flow that deposited coarse bouldery sediment along the slope-area reach as it lost volume, followed soon after by a water-flood that achieved a stage about one-half meter higher than the debris flow. The Centralia dam failure is one of three constructed dams destroyed by rapid foundation failure that defines the upper limits of an envelope curve of peak flood discharge as a function of potential energy for failed constructed dams worldwide.

Costa, John E.

1994-01-01

178

Estimating flooding potential associated with dam breach using GIS-based modeling  

Microsoft Academic Search

One of the damaging events attributable to engineering structures is inundation flooding due to dam breach. A variety of programs exist for determining the extent and magnitude of flooding downstream, which are in widespread use to determine the lives and property at risk to such a failure. The U.S. Army Corps of Engineers' Hydraulic Engineering Center's River Analysis System (HEC-RAS)

B. J. Gunter; J. S. Kuszmaul; R. M. Holt

2008-01-01

179

Estimating flooding potential associated with dam breach using GIS-based modeling  

NASA Astrophysics Data System (ADS)

One of the damaging events attributable to engineering structures is inundation flooding due to dam breach. A variety of programs exist for determining the extent and magnitude of flooding downstream, which are in widespread use to determine the lives and property at risk to such a failure. The U.S. Army Corps of Engineers' Hydraulic Engineering Center's River Analysis System (HEC-RAS) is an example of such a dam break/flood routing model used to breach a dam and route the water downstream. Producing a stable dam break model and inundation map from HEC-RAS is a process requiring days to weeks of the modelers time. Such an effort is reasonable and appropriate for a detailed examination of the risks associated with such a failure, but the demands of such an approach preclude this tool to be used for a large inventory of dams that might fall under the regulatory responsibilities of a government agency. In an effort to minimize the time required for generating dam breach inundation maps, a method was developed to delineate dam inundation using a simplified procedure that is 1) consistent with conventional practice of estimating inundation resulting from a dam breach, 2) capable of being applied broadly to data layers that are available on the scale of entire state, and 3) computationally robust to enable it to be applied across a broad set of topographic and geographic conditions. VADUS Vulnerability Assessment of Dams using Simplifications automates generation of inundation maps by extracting data from a standard set of data Geographic Information Systems (GIS) layers. The VADUS methodology is based on a combination of procedures from 1) United States Bureau of Reclamation (USBR), 2) Washington State's Department of Ecology (WSDE), and 3) United States Geological Survey (USGS). USBR's method for determining flood peak discharges downstream was used to determine the magnitude of dam break flood waves, WSDE's method of estimating flood extent due to roughness and cross-section area was incorporated to determine cross-sectional area through which peak discharge passes, and a USGS methodology for determining the areal extent of inundation was incorporated to find the extent of the flooded area. The modeling tools were applied to over 3000 dams in Mississippi across a range of sizes and geographic conditions.

Gunter, B. J.; Kuszmaul, J. S.; Holt, R. M.

2008-12-01

180

REAR PROFILE OF TAIL FROM SECOND LEVEL OF TAIL DOCK ...  

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

REAR PROFILE OF TAIL FROM SECOND LEVEL OF TAIL DOCK STAND, SHOWING AIRCRAFT NUMBER (319), HORIZONTAL STABILIZER, TAIL CONE AND COOLING CTS FOR THE AUXILIARY POWER UNIT (APU), MECHANIC PAUL RIDEOUT IS LOWERING THE BALANCE PANELS ON THE STABILIZERS FOR LUBRICATION AND INSPECTION. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

181

Diversion dam reduces decomposition, fungal biomass, and macroinvertebrate abundance and diversity: Implications for dam removal  

NASA Astrophysics Data System (ADS)

Dam decommissioning projects are rarely accompanied by adequate baseline data needed to test if the effects of dams are reversible. Although the effects of dams on aquatic species have been well-documented, there are few studies that document the effects of dams on ecosystem processes. In this study we examine how in-stream leaf litter processing rates and associated fungal and macroinvertebrate populations are affected by a dam in Fossil Creek, Arizona, which will be decommissioned in 2005. We found significantly faster decomposition rates above the dam accompanied by higher fungal biomass, invertebrate abundances and invertebrate diversity compared to below the dam. We predict that return of full flows will increase decomposition, fungal biomass, and secondary productivity in areas where flow is currently reduced. This study shows how diversion dams can inhibit ecosystem processes and provides data for testing the restoration potential of dam decommissioning on decomposition and decomposer communities.

Muehlbauer, J. D.; Lovett, J. M.; Jones, K. L.; Plichta, J. R.; Patrick, M. M.; Delaney, I. A.; Bennett, S. E.; Norman, P. A.; Flaccus, K. K.; Vlieg, J. A.; Leroy, C. J.; Marks, J. C.

2005-05-01

182

Scale-dependency of macroinvertebrate communities: responses to contaminated sediments within run-of-river dams.  

PubMed

Due to their nutrient recycling function and their importance in food-webs, macroinvertebrates are essential for the functioning of aquatic ecosystems. These organisms also constitute an important component of biodiversity. Sediment evaluation and monitoring is an essential aspect of ecosystem monitoring since sediments represent an important component of aquatic habitats and are also a potential source of contamination. In this study, we focused on macroinvertebrate communities within run-of-river dams, that are prime areas for sediment and pollutant accumulation. Little is known about littoral macroinvertebrate communities within run-of-river dam or their response to sediment levels and pollution. We therefore aimed to evaluate the following aspects: the functional and structural composition of macroinvertebrate communities in run-of-river dams; the impact of pollutant accumulation on such communities, and the most efficient scales and tools needed for the biomonitoring of contaminated sediments in such environments. Two run-of-river dams located in the French alpine area were selected and three spatial scales were examined: transversal (banks and channel), transversal x longitudinal (banks/channel x tail/middle/dam) and patch scale (erosion, sedimentation and vegetation habitats). At the patch scale, we noted that the heterogeneity of littoral habitats provided many available niches that allow for the development of diversified macroinvertebrate communities. This implies highly variable responses to contamination. Once combined on a global 'banks' spatial scale, littoral habitats can highlight the effects of toxic disturbances. PMID:21272919

Colas, Fanny; Archaimbault, Virginie; Devin, Simon

2011-03-01

183

Maximum Stream Power? Projecting Catastrophic Dam Breaks at the Mountain-Belt Scale  

NASA Astrophysics Data System (ADS)

Lake formation as a result of river damming by landslides is frequently observed in areas with steep terrain and high tectonic activity. The sudden collapse of such natural dams often generates high-magnitude floods and debris flows that pose a significant threat to human well-being and infrastructure. Furthermore, the rates of bedrock river incision may be tightly coupled with the episodic damming and emptying of these lakes as they intermittently trap sediments and abate river incision. Empirical observations show that the severity of outburst events is directly related to the impounded water volume and downstream channel morphology both of which are controlled by topography. We thus argue that prime insights into the spatial patterns of hazards generated by landslide dammed lakes should thus be inferred from digital elevation models (DEMs) that are available at sufficient detail at even the remotest localities. Here we present first results of a Himalaya-wide assessment of backwater volumes generated by a range of natural dam scenarios derived from an empirical database. The GIS based analysis utilizes SRTM3 data that was preprocessed by advanced hydrological conditioning techniques to obtain an accurate representation of drainage patterns and valley morphology. Natural dams are simulated at each river location where the adjacent topography is susceptible to landslide initiation. Backwater volumes are corrected for dam geometry modeled as a function of dam height and river gradient. The possible range of backwater volumes spans various orders of magnitude from 10-4-102 km3 with high variability within and between different dam scenarios. The frequency-magnitude distributions of simulated backwater volumes are fitted using the generalized extreme value distribution with a strong positive modal shift observed for greater dam heights. Large backwater volumes are particularly observed along the Tibetan Plateau margin and orogen-parallel river courses. We modified a dimensionless blockage index to incorporate runoff magnitudes and seasonality to develop an outburst flood immediacy index. We argue that the index is valuable for hazard mitigation and monitoring and provides a basis to further investigate the effects of outburst floods on long-term landscape evolution. Future efforts will be directed towards an assessment of downstream flood peak translation and will thus provide means to finally quantify the risks associated with the failure of naturally dammed lakes at an orogen-wide scale. We anticipate that our results will deliver quantitative estimates of volumes of involved sediment movements and thus provide important input to investigation the effects of landslide damming on bedrock river incision, and ultimately, long-term landscape evolution.

Schwanghart, W.; Bloethe, J. H.; Andermann, C.; Korup, O.

2012-12-01

184

Constraining the timing of the most recent cataclysmic flood event from ice-dammed lakes in the Russian Altai Mountains, Siberia, using cosmogenic in situ 10Be  

NASA Astrophysics Data System (ADS)

Ice-dammed lakes were repeatedly formed in intermontane basins in the Russian Altai Mountains throughout the Pleistocene. These cataclysmic outburst floods, caused by ice-dam failures, were documented as Earth's largest flood waves by other geoscientists. Using in situ 10Be, we successfully dated surfaces of flood-associated boulders located in a former lake basin and downvalley from a former ice dam. Our precise surface exposure ages suggest that all boulders were associated with the most recent out of a number of cataclysmic floods that occurred at 15.8 ± 1.8 ka. The field location of the boulders implies that they were deposited by the largest late Pleistocene flood that drained the Chuya-Katun Lake completely following initial dam failure. A published reconstruction of the late glacial paleoenvironment in the vicinity of the former ice dam indicates that dam failure was likely a result of climatically induced downwasting of glaciers. The failure of the ice dam provides more evidence for the timing of widespread warming during the late glacial in southern Russia. This flooding event in the headwaters of the Ob River coincides with a freshwater peak as recorded in isotopic records of the Kara Sea and the Arctic Ocean.

Reuther, Anne U.; Herget, Jürgen; Ivy-Ochs, Susan; Borodavko, Pavel; Kubik, Peter W.; Heine, Klaus

2006-11-01

185

ANTIBODIES TO SPIROCHETES IN WHITE-TAILED DEER AND PREVALENCE OF INFECTED TICKS FROM FOCI OF LYME DISEASE IN CONNECTICUT  

Microsoft Academic Search

White-tailed deer (Odocoileus virginianus) were examined for the tick, Ixodes dam- mini, and sera were analyzed for antibodies to spirochetes during 1982. Of the 323 animals inspected in four areas endemic for Lyme disease, 188 (58%) had adult ticks; parasitism ranged from 43% at Haddam to 82% at East Lyme. Direct and indirect fluorescent antibody tests detected spirochetes in 18

Louis A. Magnarelli; John F. Anderson; W. Adrian Chappell

186

Dynamic decision making for dam-break emergency management - Part 1: Theoretical framework  

NASA Astrophysics Data System (ADS)

An evacuation decision for dam breaks is a very serious issue. A late decision may lead to loss of lives and properties, but a very early evacuation will incur unnecessary expenses. This paper presents a risk-based framework of dynamic decision making for dam-break emergency management (DYDEM). The dam-break emergency management in both time scale and space scale is introduced first to define the dynamic decision problem. The probability of dam failure is taken as a stochastic process and estimated using a time-series analysis method. The flood consequences are taken as functions of warning time and evaluated with a human risk analysis model (HURAM) based on Bayesian networks. A decision criterion is suggested to decide whether to evacuate the population at risk (PAR) or to delay the decision. The optimum time for evacuating the PAR is obtained by minimizing the expected total loss, which integrates the time-related probabilities and flood consequences. When a delayed decision is chosen, the decision making can be updated with available new information. A specific dam-break case study is presented in a companion paper to illustrate the application of this framework to complex dam-breaching problems.

Peng, M.; Zhang, L. M.

2013-02-01

187

A tool to aid emergency managers and communities in appraising private dam safety and policy.  

PubMed

Issues concerning dam safety and equitable sharing of catchment run-off are receiving more attention throughout the world. This paper assesses these matters in the context of Australia, and the need for policy responses. Landholders often overlook the common law obligation to review/design dams to current standards because of high costs, leaving them vulnerable to litigation if their dam fails. The paper reports on an innovative spillway design/review procedure, applicable to southeast Australia, but transferable to any region worldwide. Dam safety policy models and guidelines derived from international best practice are linked to the procedure and intended to aid government decision-making. The procedure minimises costs to landholders and provides an acceptable level of safety assurance to downstream communities. Also discussed are recent surveys testing community attitudes to the procedure and implemented dam safety and water allocation policies. These further guide any government wanting to implement this'integrated engineering and community partnerships'approach to preventing potential disasters due to private dam failure and achieving sustainable and safe water storage and use. PMID:17461922

Pisaniello, John D; McKay, Jennifer

2007-06-01

188

Egypt: after the Aswan Dam  

SciTech Connect

Ten years after its completion, the controversial Aswan High Dam's hydrologic and human consequences are clearer because of a joint US-Egyptian interdisciplinary study. Water supply and distribution is emerging as a major world resource problem with the recognition that unsafe drinking water and inadequate sanitation contribute to health problems. Dams provide water supplies, but they also create conditions favorable to the spread of water-borne diseases. The Aswan Dam solved problems of flooding and drought by opening 2.5 million acres to year-round irrigation, although some of the reclaimed land has been lost to urban expansion and shoreline erosion, and provides hydroelectric power. The negative effects include increasing soil salinity, changes in the water table, excessive downstream water plant growth, and diseases such as schistosomiasis and other intestinal parasites, and the social impact on the Nubians, whose homeland was flooded. Planners must use the information gathered in this study to see that the benefits outweigh the human costs. 22 references, 7 figures.

Walton, S.

1981-05-01

189

Faun tail nevus  

PubMed Central

Faun tail nevus is a posterior midline cutaneous lesion of importance to dermatologists as it could be a cutaneous marker for its underlying spine and spinal cord anomaly. We report a 13-year-old girl with excessive hair growth over the lumbosacral region since birth. There was associated spinal anomaly with no neurological manifestation affecting the lower spinal cord. The diagnosis was made on clinical basis. The patient reported for cosmetic disability. This case is reported for its clinical importance.

Yamini, M.; Sridevi, K. S.; Babu, N. Prasanna; Chetty, Nanjappa G.

2011-01-01

190

Modelling Cometary Sodium Tails  

NASA Astrophysics Data System (ADS)

Neutral sodium is readily observed in cometary spectra and can be seen to form its own distinct tail at high activity comets. Solar radiation pressure accelerates the sodium atoms antisunward and, as strong sodium absorption lines are present in the solar spectrum, the magnitude of this force is dependent upon the Doppler shift of the incident solar radiation. Therefore the heliocentric velocity of the sodium atom directly determines its acceleration. This can produce unique effects, such as a stagnation region. Sodium is relatively easy to detect and so can potentially be used to trace mechanisms in the coma that are otherwise difficult to observe. The source of neutral sodium in the tail currently remains unknown. We have therefore developed a new, three dimensional Monte-Carlo model of neutral cometary sodium in order to facilitate testing of different source production functions. It includes weightings due to neutral sodium lifetime, variation of cometary sodium emission due to Fraunhofer absorption lines and solar flux variation with heliocentric distance. The Swings and Greenstein effects, which can have particularly dramatic effects in near-Sun comets, are also considered comprehensively. Preliminary results from this model are presented, focusing on a comparison of predictions of the neutral sodium tail of Comet C/2012 S1 (ISON) with initial observations.

Birkett, K. S.; Jones, G. H.; Coates, A. J.

2013-12-01

191

The tail plane  

NASA Technical Reports Server (NTRS)

This report deals with the calculation of the equilibrium, statistical stability, and damping of the tail plane. The author has simplified the present theory of longitudinal stability for the particular purpose of obtaining one definite coefficient characteristics of the effect of the tail plane. This coefficient is obtained by substituting certain aerodynamic characteristics and some dimensions of the airplane in a comparatively simple mathematical expression. Care has been taken to confine all aerodynamical information necessary for the calculation of the coefficient to the well-known curves representing the qualities of the wing section. This is done by making use of the present results of modern aerodynamics. All formulas and relations necessary for the calculation are contained in the paper. They give in some cases only an approximation of the real values. An example of calculation is added in order to illustrate the application of the method. The coefficient indicates not only whether the effect of the tail plane is great enough, but also whether it is not too great. It appears that the designer has to avoid a certain critical length of the fuselage, which inevitably gives rise to periodical oscillations of the airplane. The discussion also shows the way and in what direction to carry out experimental work.

Munk, Max M

1923-01-01

192

Analysis of dam safety management system in China  

Microsoft Academic Search

Due to an increasing amount of dam damage or break in resent years, great importance is attached to dam safety management in many countries. This paper analyzes the status of Chinese dam safety management according to the integral safety concept for dam including structural safety, dam safety monitoring, operational safety and emergency planning. Comparing with the safety management of large

Cheng Cuiyun; Qian Xin; Zhang Yuchao; Sheng Jinbao

2010-01-01

193

18. DETAIL AT JUNCTION OF MAIN DAM AT LEFT AND ...  

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

18. DETAIL AT JUNCTION OF MAIN DAM AT LEFT AND DIVERSION DAM AT RIGHT SHOWING LOG CRIBBING. SPACES INSIDE CRIBBING WERE FILLED WITH STONE TO ANCHOR DAM; DETERIORATION OF DAM HAS ALLOWED STONE BALLAST TO WASH AWAY. Photographed July 18, 1938. - Forge Creek Dam-John Cable Mill, Townsend, Blount County, TN

194

PROBABILISTIC METHOD FOR SEISMIC VULNERABILITY RANKING OF CANADIAN HYDROPOWER DAMS  

Microsoft Academic Search

A probabilistic method was developed for ranking Canadian hydropower dams according to their seismic vulnerability. The method is based on the probabilistic seismic hazard at the dam location, the seismic fragility of the dam, and the construction date of the dam. The seismic hazard is represented by the peak ground acceleration of seismic motions at the dam location for a

Lan Lin; John Adams

195

Exporting dams: China's hydropower industry goes global.  

PubMed

In line with China's "going out" strategy, China's dam industry has in recent years significantly expanded its involvement in overseas markets. The Chinese Export-Import Bank and other Chinese financial institutions, state-owned enterprises, and private firms are now involved in at least 93 major dam projects overseas. The Chinese government sees the new global role played by China's dam industry as a "win-win" situation for China and host countries involved. But evidence from project sites such as the Merowe Dam in Sudan demonstrates that these dams have unrecognized social and environmental costs for host communities. Chinese dam builders have yet to adopt internationally accepted social and environmental standards for large infrastructure development that can assure these costs are adequately taken into account. But the Chinese government is becoming increasingly aware of the challenge and the necessity of promoting environmentally and socially sound investments overseas. PMID:18992986

McDonald, Kristen; Bosshard, Peter; Brewer, Nicole

2009-07-01

196

Winnibigoshish Dam, Mississippi River, Minnesota, Reconnaissance Report for Dam Safety Assurance Program.  

National Technical Information Service (NTIS)

This reconnaissance report evaluates the Winnibigoshish Dam and Lake project for potential safety hazards using current standards and state of the art. Winnibigoshish Dam is located on the Mississippi River in north central Minnesota, 1247.9 river miles a...

1985-01-01

197

78 FR 53494 - Dam Safety Modifications at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams  

Federal Register 2010, 2011, 2012, 2013

...Modifications of Dam Structures: Combination of Concrete Floodwalls and Earthen Embankments...Bar). TVA also installed a permanent concrete apron on approximately 2 acres of the...Modifications of Dam Structures: Combination of Concrete Floodwalls and Earthen...

2013-08-29

198

Hoover Dam: The American Experience Online  

NSDL National Science Digital Library

The American Experience Online presents this companion site to its recent American Experience film about the one of the greatest hydroengineering feats in history. The Hoover Dam, in Black Canyon on the Colorado River, at the Arizona-Nevada border, was built between 1930 and 1936 and is the highest concrete arch dam in the US. The site provides a program description, an enhanced transcript of the film, a brief bibliography, a list of the dam facts, an essay that explores the economic and environmental effects of the dam, a timeline, a map, a People and Events Database, and a teacher's guide.

1999-01-01

199

World Wide Web Pages for Dam Design  

NSDL National Science Digital Library

This site is a very informative and well presented resource for dam design, primarily intended to give undergraduates or anyone interested in the subject a solid introduction to the basic concepts. Maintained at the University of Durham in Britain, there are many sections that provide a good overview of the many processes involved in building a dam. Many different types of dams are described in detail, including concrete and embankment dams. Hydrology and geology, important factors that need to be considered when choosing a suitable location, are also covered. The layout of the site is fairly good overall, but navigating the many sections and subsections can sometimes get confusing.

1997-01-01

200

Defining Successful Dam Removal and Shifting the Focus of Restoration; A Midwest Perspective.  

NASA Astrophysics Data System (ADS)

The number of dam removals in the US has increased in the last decade because design lives are being exceeded for an increasing number of dams, and because interest groups have pushed for removal as part of attempts to restore river ecology. Large numbers of small dams have been removed, despite the paucity of information regarding the physical and biological impacts of removal. Here we offer a Midwestern perspective on dam removal, based on issues endemic to rivers of this region. In the absence of comprehensive national studies of dam removal, regionally specific studies provide a starting point for the debate over the efficacy of dam removal as a river restoration tool. Three of the most important issues in Midwestern river management are; excessive nutrient export, endangered mussel populations, and high sediment inputs. Some of the most diverse assemblages of freshwater mussels reside in the Midwest. These populations have been historically impacted by over-harvesting and increased sediment inputs to lotic environments. Dam removal results in two impacts that operate against mussel populations. First, the rapid dewatering of the upstream reservoir can cause nearly total mortality of the upstream (impoundment) community. Second, large volumes of sediment are released and deposited into downstream reaches, effectively smothering downstream communities. Sediment deposition downstream exacerbates the well-documented negative impacts that years of poor land use have had on stream and river biota, thus not only does deposition impact mussel communities, but interferes with all aquatic communities. Closely related to the movement of sediment out of the former impoundment is the export of nutrients. Issues of eutrophication have been documented in water bodies ranging from small receiving lakes to the Gulf of Mexico. Removing a dam releases nutrients that have been stored for the duration of the dam's existence, allowing them to flow downstream in a concentrated release that can last long after the initial removal. All three key Midwestern river management issues are directly impacted by the removal of dams. Though few comprehensive studies have quantified specific impacts following removal, information from chance failure observations and unpublished documentation can be used to support the argument that dam removal evaluation should move away from perceived needs, such as restoring connectivity and opening up habitat for non-endangered aquatic species, toward other relevant regional issues. Given the importance of excessive nutrient export, endangered mussel populations, and high sediment inputs, they should be substantial components in defining the potential success of removal as a restoration option in the Midwest, and possibly other areas of the US.

Selle, A. R.; Doyle, M. W.; Stanley, E. H.; Harbor, J. M.; Lyn, D. A.

2002-12-01

201

10. BRIDGE IN CONTEXT OF DAM, THIRD POWER HOUSE IN ...  

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

10. BRIDGE IN CONTEXT OF DAM, THIRD POWER HOUSE IN FOREGROUND, LOOKING NORTH BY 360 DEGREES - Columbia River Bridge at Grand Coulee Dam, Spanning Columbia River at State Route 155, Coulee Dam, Okanogan County, WA

202

10. DIABLO DAM: DETAIL OF TAINTOR GATES FROM UPSTREAM ON ...  

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

10. DIABLO DAM: DETAIL OF TAINTOR GATES FROM UPSTREAM ON NORTH END OF DAM, 1989. - Skagit Power Development, Diablo Dam, On Skagit River, 6.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

203

77 FR 9265 - Glen Canyon Dam Adaptive Management Work Group  

Federal Register 2010, 2011, 2012, 2013

...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

2012-02-16

204

78 FR 47695 - Sam Rayburn Dam Power Rate  

Federal Register 2010, 2011, 2012, 2013

...Southwestern Power Administration Sam Rayburn Dam Power Rate AGENCY: Southwestern Power Administration...SUMMARY: The current Sam Rayburn Dam Project rate was approved by the Federal...Southwestern has developed a proposed Sam Rayburn Dam rate to recover the required...

2013-08-06

205

77 FR 67813 - Sam Rayburn Dam Project Power Rate  

Federal Register 2010, 2011, 2012, 2013

...Southwestern Power Administration Sam Rayburn Dam Project Power Rate AGENCY: Southwestern...existing power rate for the Sam Rayburn Dam Project (Rayburn), Rate Schedule SRD-08...Hydro Power and Energy Sold to Sam Rayburn Dam Electric Cooperative, Inc., for a...

2012-11-14

206

77 FR 22801 - Glen Canyon Dam Adaptive Management Work Group  

Federal Register 2010, 2011, 2012, 2013

...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

2012-04-17

207

78 FR 7810 - Glen Canyon Dam Adaptive Management Work Group  

Federal Register 2010, 2011, 2012, 2013

...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

2013-02-04

208

78 FR 21415 - Glen Canyon Dam Adaptive Management Work Group  

Federal Register 2010, 2011, 2012, 2013

...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

2013-04-10

209

76 FR 24516 - Glen Canyon Dam Adaptive Management Work Group  

Federal Register 2010, 2011, 2012, 2013

...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...SUMMARY: The Glen Canyon Dam Adaptive Management Work Group (AMWG...Secretary of the Interior concerning Glen Canyon Dam operations and other management...

2011-05-02

210

2. East side of lower dam shown with water flowing ...  

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

2. East side of lower dam shown with water flowing over dam. VIEW WEST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

211

14. VIEW OF DAM SITE, LOOKING SOUTH (DOWNSTREAM). MIXING PLANT ...  

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

14. VIEW OF DAM SITE, LOOKING SOUTH (DOWNSTREAM). MIXING PLANT IS VISIBLE AT RIGHT, COFFER DAM IS UPSTREAM OF PLACING TOWER. EAST DOME IS VISIBLE AT LEFT OF TOWER, c. 1927 - Coolidge Dam, Gila River, Peridot, Gila County, AZ

212

21 CFR 872.6300 - Rubber dam and accessories.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Rubber dam and accessories. 872.6300 Section... Miscellaneous Devices § 872.6300 Rubber dam and accessories. (a) Identification. A rubber dam and accessories is a device...

2013-04-01

213

1996 McNary Dam, Ice Harbor Dam, and Lower Monumental Dam Smolt Monitoring Program. Annual report.  

National Technical Information Service (NTIS)

The Washington Department of Fish & Wildlife (WDFW) assumed responsibility for the Smolt Monitoring Program at McNary Dam on the Columbia River in 1990 and at the new juvenile collection facility at Lower Monumental Dam on the Snake River in 1993. In 1996...

T. Hillson P. Hoffarth S. Lind W. Price R. Tudor

1997-01-01

214

Fragility Analysis of Concrete Gravity Dams  

NASA Astrophysics Data System (ADS)

Concrete gravity dams are an important part ofthe nation's infrastructure. Many dams have been in service for over 50 years, during which time important advances in the methodologies for evaluation of natural phenomena hazards have caused the design-basis events to be revised upwards, in some cases significantly. Many existing dams fail to meet these revised safety criteria and structural rehabilitation to meet newly revised criteria may be costly and difficult. A probabilistic safety analysis (PSA) provides a rational safety assessment and decision-making tool managing the various sources of uncertainty that may impact dam performance. Fragility analysis, which depicts fl%e uncertainty in the safety margin above specified hazard levels, is a fundamental tool in a PSA. This study presents a methodology for developing fragilities of concrete gravity dams to assess their performance against hydrologic and seismic hazards. Models of varying degree of complexity and sophistication were considered and compared. The methodology is illustrated using the Bluestone Dam on the New River in West Virginia, which was designed in the late 1930's. The hydrologic fragilities showed that the Eluestone Dam is unlikely to become unstable at the revised probable maximum flood (PMF), but it is likely that there will be significant cracking at the heel ofthe dam. On the other hand, the seismic fragility analysis indicated that sliding is likely, if the dam were to be subjected to a maximum credible earthquake (MCE). Moreover, there will likely be tensile cracking at the neck of the dam at this level of seismic excitation. Probabilities of relatively severe limit states appear to be only marginally affected by extremely rare events (e.g. the PMF and MCE). Moreover, the risks posed by the extreme floods and earthquakes were not balanced for the Bluestone Dam, with seismic hazard posing a relatively higher risk.

Tekie, Paulos B.; Ellingwood, Bruce R.

2002-09-01

215

The geomagnetic tail  

SciTech Connect

A review is presented of the plasma sheet and lobe regions of the magnetotail, focusing principally on large-scale processes or microprocesses with some large-scale effects. Consideration is given to quiet and average structures, not necessarily related to activity phases, with quasi-steady convection aspects, and with the characteristics of dynamic phases including acceleration mechanisms and single particle aspects. Attention is given to various activity models, average and quiet time properties, properties and effects of magnetospheric convection, dynamics of the magnetotail, and the near tail, substorm current wedge.

Birn, J. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

216

Experiments in dam removal, sediment pulses and channel evolution on the Clark Fork River, MT and White Salmon River, WA  

NASA Astrophysics Data System (ADS)

Two recent dam removals on tributaries to the Columbia River in the northwestern United States present contrasting examples of how dam removal methods, reservoir contents, and geomorphic settings influence system responses. The 2008 removal of Milltown Dam, from the Clark Fork River (CFR), Montana, and the 2011 removal of Condit Dam from the White Salmon River (WSR), Washington (Table 1), represent two of the largest dam removals to date. The Milltown Dam removal was notable because the dam stored millions of cubic meters of contaminated mine tailings, a portion of which were excavated as part of Superfund remediation but a portion of which flowed downstream after the removal. On the CFR, post-breach high flows in 2008 produced reservoir erosion and downstream deposition in bed interstices, along bars, and on the floodplain, but above-average (3-15 year recurrence interval) floods since then have remobilized this material and have, to a large extent, erased signs of downstream sedimentation. The Condit Dam removal entailed dynamiting of a 4m by 5.5m hole at the base of the dam, which produced rapid and dramatic draining of fine reservoir sediments within hours of the blast. Downstream of Condit Dam, the initial hyperconcentrated flows and sediment pulse draped the WSR with fine sediment, filled pools, and, in an unconfined reach influenced by the Columbia River's backwater, caused meters of aggradation and new bar formation. In the confined, bedrock-dominated reach downstream of the Condit site, pool-riffle structure has started to reemerge as of summer 2012 and the finest bed materials have been evacuated from the main channel, although sediment storage in pools and eddies persists. Whereas post-breach geomorphic responses on the CFR have been largely driven by hydrology, the post-breach evolution of the WSR has been predominantly influenced by antecedent geomorphic conditions (slope, confinement, and Columbia River backwater). On both the CFR and WSR, the pace of post-breach reservoir erosion and of geomorphic recovery from the disturbances produced by dam removal has been rapid, far exceeding pre-breach predictions.Table 1: Comparison of Milltown and Condit Dam removals

Wilcox, A. C.

2012-12-01

217

McNary Dam, Ice Harbor Dam, and Lower Monumental Dam Smolt Monitoring Program; 1996 Annual Report.  

SciTech Connect

The Washington Department of Fish & Wildlife (WDFW) assumed responsibility for the Smolt Monitoring Program at McNary Dam on the Columbia River in 1990 and at the new juvenile collection facility at Lower Monumental Dam on the Snake River in 1993. In 1996, Smolt Monitoring Program activities also began at the new juvenile collection facility located at Ice Harbor Dam. This report summarizes the 1996 Smolt Monitoring work at all three sites. The work at Ice Harbor consisted of Gas Bubble Trauma (GBT) monitoring only. In general, the 1996 passage season at both the McNary and Lower Monumental sites can be characterized by reduced passage of juveniles through the collection systems due to elevated river flows and spill, and low (<1%) overall facility mortality rates most likely resulting from cooler water temperatures. In accordance with the National Marine Fisheries Service recommendations (NMFS, 1995) all spring migrants were bypassed at McNary Dam in 1996. Mechanical problems within the McNary collection system resulted in collection and sampling activities being delayed until April 18 at this site, while sampling and collection began on the scheduled starting date of April 1 at Lower Monumental Dam. Monitoring operations were conducted through December 14 at McNary Dam and through October 28 at Lower Monumental Dam. An ongoing transportation evaluation summer migrant marking program was conducted at McNary Dam in 1996 by the NMFS. This necessitated the sampling of 394,211 additional fish beyond the recommended sampling guidelines. All total, 509,237 and 31,219 juvenile salmonids were anesthetized and individually counted, examined for scale loss, injuries, and brands by WDFW Smolt Monitoring personnel in 1996 at McNary Dam and Lower Monumental Dam, respectively.

Hillson, Todd; Lind, Sharon; Price, William (Washington Department of Fish and Wildlife, Olympia, WA)

1997-07-01

218

Helicopter Tail-Boom Strakes  

NASA Technical Reports Server (NTRS)

Yaw control and overall efficiency increased at hover and low speeds. Wind-tunnel investigation showed strake located on left side of tail boom has potential to reduce high adverse side loads on tail boom in hover and in sideward flight. Test demonstrated addition of single long strake to left side of tail boom most effective configuration for reducing left pedal requirements in right sideward flight.

Kelley, H. L.; Phelps, A. E., III; Wilson, J. C.

1986-01-01

219

Estimating flow through an earthen dam  

NSDL National Science Digital Library

Students make measurements of dam dimensions and water levels above and below a small, accessible earthen dam. They assess the soil texture in the field. They follow up by developing a simple flow net and estimating seepage rate as part of a problem set. They discuss their assumptions and the likely sources and magnitude of error.

Savage, Kaye

220

Historic American Engineering Record, Stewart Mountain Dam.  

National Technical Information Service (NTIS)

The report provides a written narrative of the events leading to the construction of Stewart Mountain Dam on the Salt River, in Central Arizona. Stewart Mountain Dam was constructed by the Salt River Valley Water Users' Association between 1928 and 1930. ...

D. C. Jackson

1992-01-01

221

Historic American Engineering Record: Horseshoe Dam.  

National Technical Information Service (NTIS)

The report provides a written narrative of the events leading to the construction of Horseshoe Dam on the Verde River, in Central Arizona. Horseshoe Dam was constructed between 1944 and 1946 by the Salt River Valley Water Users' Association and the Phelps...

D. C. Jackson C. B. Fraser

1991-01-01

222

Horizontal displacements of rock foundations of dams  

SciTech Connect

This paper uses geodetic survey methods to assess the horizontal displacements of dam foundations for several hydroelectric power plants in the Soviet Union. The effects of filling the reservoirs are outlined and the dependence of the degree of displacement on dam height is analyzed. The results are tabulated.

Karlson, A.A.

1987-08-01

223

104. DAM TAINTER GATE NONSUBMERGIBLE UPPER FRAME ...  

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

104. DAM - TAINTER GATE - NON-SUBMERGIBLE - UPPER FRAME AND SKIN PLATE (ML-8-48/2-FS) June 1935 - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

224

Uranium mill tailings and radon  

SciTech Connect

The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the US may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action Program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

Hanchey, L A

1981-01-01

225

Uranium mill tailings and radon  

SciTech Connect

The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is extremely small. If the assumptions used in the studies are correct, one or two people per year in the United States may develop cancer as a result of radon exhaled from all the Uranium Mill Tailings Remedial Action program sites. The remedial action should reduce the hazard from the tailings by a factor of about 100.

Hanchey, L A

1981-04-01

226

Time-Lapse Seismic Tomography and Electrical Resistivity Mapping of a Small Embankment Dam with Possible Zones of Weakness  

NASA Astrophysics Data System (ADS)

Earthen dam or levee failure can occur with little to no warning. Internal problems such as seepage and piping are among the major causes of failure in earthen embankment dams and levees. Identifying and mitigating these problems requires a cost effective and non-invasive method of investigating these critical structures. This study focuses on the early detection of internal problems such as seepage and piping using time lapse seismic refraction tomography (SRT) and electrical resistivity tomography (ERT). For this study, two quarter scale model dams were built at the USDA-ARS Hydraulic Engineering Research Unit in Stillwater, OK. These dams were constructed with two internal compromised zones that would be susceptible to seepage and piping. The zones consist of a sandy region and a region compacted at lower moisture content. Time lapse seismic refraction and electrical resistivity measurements were conducted over a course of two years to monitor changes in the internal structure of the model dams due to seasonal changes, cyclic loadings and internal erosion failure. The results will provide an insight on how compromised zones due to seepage and piping can be identified at an early stage using both SRT and ERT time-lapse measurements and how joint interpretation of these two methods helps in closely identifying what attributed to the compromised zone. [This research was funded by the department of Homeland Security- sponsored Southeast Region Research Initiative (SERRI) at the Department of Energy's Oak Ridge National Laboratory.

Wodajo, L. T.; Hickey, C. J.; Song, C. R.

2013-12-01

227

Do we need construct more dams?  

NASA Astrophysics Data System (ADS)

This paper reviews global dam development in association with the growths of global population, economy, and energy consumption in the past several decades, and also evaluates contributions of dam development to future world sustainable development. Eventually, this paper answers whether we need more dams in the future or not. The world population has rapidly increased from 1.6 billion in 1900, 2.5 billion in 1950, 6.1 billion in 2000, to 7.0 billion in 2011, and is projected to reach 9.5 billion in 2050; similarly, the world economy has dramatically expanded. To maintain socioeconomic development, the consumption of water, food and energy has increased rapidly as well. However, the total volume of available water resource over the world is limited, the food production largely depends on water supply, and the main energy sources are still oil, coal and gas at present, which are regarded as non-renewable resources. Accordingly, it is expected that we will face serious problems to deal with the challenges of water crisis, food security and energy shortage in the near future. In order to enhance the capability of regulating water resource, a great number of global dams (and related reservoirs) have been constructed in the last one hundred years; currently, almost all large rivers over the world have been regulated by dams. The reservoirs can supply sufficient water for irrigated land to ensure food production, and the associated hydropower stations can generate electricity. This article collects the dam data from the ICOLD (International Commission on Large Dams) and GRanD (Global Reservoir and Dam) databases, and some socioeconomic data, including population, economy, and consumptions of water, food and energy over the world. Analysis of these data reveals that global dam development has a great impact on the world sustainable development. Further, it is concluded that we need further dam development to maintain our future development.

Chen, J.; Shi, H.

2013-12-01

228

[Limnetic zooplankton run-off a high-head dam and their fate in a river with high current velocity (case of the Krasnoiarsk hydroelectric power station on the Yenisei river].  

PubMed

The vertical distribution of net zooplankton in head-water of Krasnoyarsk hydroelectric power station and its horizontal distribution in the tail-water were studied during two years in winter and summer seasons. In order to distinguish living and dead individuals the special staining was used. It was revealed that on average 77% of living plankton pass through high-head dam with deep water scoop to the tailwater. While passing through dam aggregates some individuals of the reservoir plankton are traumatized and die, that results in some increase of portion of dead individuals in the tail water near dam (from 3 to 6%). Alive zooplankton passed through the dam aggregates is eliminated under the Upper Yenisei highly turbulent conditions. There is approximately 10% of it in 32 km from the dam if compare with biomass in 20-40 m layer of reservoir, the portion of dead increases to 11%. The biomass of zooplankton suspended in the water column of the tail-water sometimes increases (till > 1 g/m3) due to large Copepoda Heteroscope borealis, which inhabits near-bottom and near-shore river zones and can be found in the central part of the river during reproductive period. Limnetic zooplankton from the reservoir cannot be considered as important food for planktivores in the tail-water. PMID:15032067

Dubovskaia, O P; Gladyshev, M I; Makhutova, O N

2004-01-01

229

Application of parallel computing to seismic damage process simulation of an arch dam  

NASA Astrophysics Data System (ADS)

The simulation of damage process of high arch dam subjected to strong earthquake shocks is significant to the evaluation of its performance and seismic safety, considering the catastrophic effect of dam failure. However, such numerical simulation requires rigorous computational capacity. Conventional serial computing falls short of that and parallel computing is a fairly promising solution to this problem. The parallel finite element code PDPAD was developed for the damage prediction of arch dams utilizing the damage model with inheterogeneity of concrete considered. Developed with programming language Fortran, the code uses a master/slave mode for programming, domain decomposition method for allocation of tasks, MPI (Message Passing Interface) for communication and solvers from AZTEC library for solution of large-scale equations. Speedup test showed that the performance of PDPAD was quite satisfactory. The code was employed to study the damage process of a being-built arch dam on a 4-node PC Cluster, with more than one million degrees of freedom considered. The obtained damage mode was quite similar to that of shaking table test, indicating that the proposed procedure and parallel code PDPAD has a good potential in simulating seismic damage mode of arch dams. With the rapidly growing need for massive computation emerged from engineering problems, parallel computing will find more and more applications in pertinent areas.

Zhong, Hong; Lin, Gao; Li, Jianbo

2010-06-01

230

Seismic Analysis of Morrow Point Dam  

SciTech Connect

The main objective of this study is to perform nonlinear dynamic earthquake time history analyses on Morrow Point Dam, which is located 263 km southwest of Denver, Colorado. This project poses many significant technical challenges, one of which is to model the entire Morrow Point Dam/Foundation Rock/Reservoir system which includes accurate geology topography. In addition, the computational model must be initialized to represent the existing dead loads on the structure and the stress field caused by the dead loads. To achieve the correct dead load stress field due to gravity and hydrostatic load, the computer model must account for the manner in which the dams were constructed. Construction of a dam finite element model with the correct as-built geometry of the dam structure and simply ''turning on'' gravity in the computer model will generally lead to an incorrect initial stress field in the structure. The sequence of segmented lifts typical of dam construction has a significant impact on the static stress fields induced in the dam. In addition, the dam model must also account for the interaction between the adjacent dam segments across the dam contraction joints. As a result of these challenges, it was determined that a significant amount of code development was required in order to accurately simulate the motion of the dam structure. Modifications to the existing slide surfaces are needed to allow for appropriate modeling of the shear keys across the contraction joints. Furthermore, a model for hydrodynamic interaction was also implemented into NIKE3D and DYNA3D for fluid representation in the 3D dam system finite element model. Finally, the modeling of the 3D dam system results in a very large computational model, which makes it difficult to perform a static initialization using an implicit code. Traditionally, for these large models, the model has been initialized over a long time scale using an explicit code. However, recent advancements have made it possible to run NIKE3D in ''parallel'' on relatively small parallel machines as well as on the ASCI platforms.

Noble, C R

2002-04-01

231

Teratoma in Human Tail Lipoma  

Microsoft Academic Search

We report a case of a rare congenital teratoma that developed in a lipoma attached to a remnant human tail. A male newborn baby presented with a large, 3-cm mass with an open margin, which pedunculated from a tail attached to the midline skin of the coccygeal area. Magnetic resonance images demonstrated multiple sacral spinal bifida without cord tethering, and

Se-Hyuck Park; Jee Soon Huh; Ki Hong Cho; Yong Sam Shin; Se Hyck Kim; Young Hwan Ahn; Kyung Gi Cho; Soo Han Yoon

2005-01-01

232

Helicopter Tail Rotor Noise Analyses.  

National Technical Information Service (NTIS)

A study was made of helicopter tail rotor noise, particularly that due to interactions with the main rotor tip vortices, and with the fuselage separation mean wake. The tail rotor blade-main rotor tip vortex interaction is modelled as an airfoil of infini...

A. R. George S. T. Chou

1986-01-01

233

On Tail Biting Convolutional Codes  

Microsoft Academic Search

In this paper, we introduce generalized tail biting encoding as a means to ameliorate the rate deficiency caused by zero-tail convolutional encoding. This technique provides an important link between quasi-cyclic block and convolutional codes. Optimum and suboptimum decoding algorithms for these codes are described and their performance determined by analytical and simulation techniques.

H. H. Ma; J. Wolf

1986-01-01

234

Uranium Mill Tailings and Radon.  

National Technical Information Service (NTIS)

The major health hazard from uranium mill tailings is presumed to be respiratory cancer resulting from the inhalation of radon daughter products. A review of studies on inhalation of radon and its daughters indicates that the hazard from the tailings is e...

L. A. Hanchey

1981-01-01

235

Human tail with spina bifida.  

PubMed

A true human tail is a rare occurrence and is defined as a caudal, vestigial, midline protrusion with skin covering connective tissue, muscle, vessels and nerves. We report a case of true human tail in a child, which is a very rare happening in humans. PMID:19922280

Chauhan, S P S; Gopal, N N; Jain, Mohit; Gupta, Anurag

2009-12-01

236

Runaway tails in magnetized plasmas  

NASA Technical Reports Server (NTRS)

The evolution of a runaway tail driven by a dc electric field in a magnetized plasma is analyzed. Depending on the strength of the electric field and the ratio of plasma to gyrofrequency, there are three different regimes in the evolution of the tail. The tail can be (1) stable with electrons accelerated to large parallel velocities, (2) unstable to Cerenkov resonance because of the depletion of the bulk and the formation of a positive slope, (3) unstable to the anomalous Doppler resonance instability driven by the large velocity anisotropy in the tail. Once an instability is triggered (Cerenkov or anomalous Doppler resonance) the tail relaxes into an isotropic distribution. The role of a convection type loss term is also discussed.

Moghaddam-Taaheri, E.; Vlahos, L.; Rowland, H. L.; Papadopoulos, K.

1985-01-01

237

Reply [to “Lake Nyos Dam  

NASA Astrophysics Data System (ADS)

The Lake Nyos natural d am consists largely of unconsolidated pyroclastic surge deposits emplaced during the formation of Nyos maar [Lockwood et al., 1987]. The emplacement age of the d am is critical for an evaluation of this flood hazard to northwestern Cameroon and eastern Nigeria, and for preparation of mitigation strategies. Carbonized wood from the base of the d am has been dated at 5000 and 400 years B.P. by Lockwood and Rubin [1988]. Because of the lack of weathering or of significant erosion of the associated pyroclastic deposits around Lake Nyos we suggested that the youngest radiocarbon age (0.4 kyr) best dated the formation of the Nyos maar and present dam. The 5-kyr date was obtained on water-worn material in stream deposits beneath the pyroclastic section; we suggested that this sample was contaminated by radiogenically “dead” CO2.

Lockwood, John P.

238

Analysis and dynamic modeling of a moraine failure and glacier lake outburst flood at Ventisquero Negro, Patagonian Andes (Argentina)  

NASA Astrophysics Data System (ADS)

SummaryAlthough moraine dams are inherently prone to failure because of their often weak structure, loose internal composition and lack of an engineered spillway, the understanding of dam breaching processes remains largely incomplete and appropriate modeling approaches are scarce. This paper analyzes a recent glacier lake outburst, caused by the failure of the terminal moraine of Ventisquero Negro (Patagonian Andes, Argentina) in May 2009. The dam breach trigger, breaching and lake emptying processes, plus the dynamics of the outburst flood were reconstructed based on field evidence and the application of a dynamic dam break model. Results indicate that the moraine failure was caused most probably by a rising lake level due to heavy precipitation, resulting in high lake outflow which led to dam erosion and finally to dam failure. The lake volume of ca. 10 × 106 m3 was released in ca. 3 h, producing high-discharge (ca. 4100 m3 s-1) debris flows and hyperconcentrated flows as the escaping water entrained large volumes of clastic material. The methodology presented in this paper provides valuable insights into complex dam breach and GLOF processes, and closes a critical gap in dynamic dam break modeling aimed at providing the lake outburst hydrograph. An accurate determination of outburst hydrographs constitutes one of the most crucial aspects for hazard assessment of unstable lakes and will gain further importance with ongoing glacier retreat and glacier lake formation.

Worni, Raphael; Stoffel, Markus; Huggel, Christian; Volz, Christian; Casteller, Alejandro; Luckman, Brian

2012-06-01

239

Recovery of Potash Feldspar from Molybdenite Tailings.  

National Technical Information Service (NTIS)

The Bureau of Mines used several laboratory batch flotation schemes combined with magnetic separation to investigate the feasibility of recovering potash feldspar and glass sands from molybdenite tailings. Four molybdenite tailings or prospective tailings...

W. H. Eddy G. V. Sullivan

1980-01-01

240

Methane release below a tropical hydroelectric dam  

NASA Astrophysics Data System (ADS)

Tropical reservoirs upstream from hydroelectric dams are known to release significant amounts of methane to the atmosphere. Here we demonstrate that methane emissions downstream from hydroelectric dams can also be large. Emissions of CH4 downstream of Balbina reservoir in the central Amazon basin (Brazil) were calculated from regular measurements of degassing in the outflow of the turbines and downstream diffusive losses. Annual emissions from the reservoir surface and downstream from the dam were 34 and 39 Gg C, respectively. The downstream emission alone represented the equivalent of 3% of all methane released from central Amazon floodplain.

Kemenes, Alexandre; Forsberg, Bruce Rider; Melack, John Michael

2007-06-01

241

46. Photocopy of photograph, c. 1933. VIEW OF DAM AND ...  

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

46. Photocopy of photograph, c. 1933. VIEW OF DAM AND FOREBAY. NOTE ALL WATER FLOWING THROUGH FOREBAY AND OUT EITHER TAILRACE OR SLUICE GATE (INSTEAD OF OVER DAM) BECAUSE OF LOW WATER FLOW. (Courtesy of the Potomac Edison Company Library (Hagerstown, MD), Historical Data Files, Dam No. 5 listing - Dam No. 5 Hydroelectric Plant, On Potomac River, Hedgesville, Berkeley County, WV

242

8. WEST DAM, LOOKING DUE NORTH OVER TOP OF WEST ...  

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

8. WEST DAM, LOOKING DUE NORTH OVER TOP OF WEST DAM, SHOWING RELATIONSHIP BETWEEN OUTLET TO RIGHT OF DAM, NEW PUMP PLANT BUILDING AND CANAL TO LEFT OF DAM. - Eastside Reservoir, Diamond & Domenigoni Valleys, southwest of Hemet, Hemet, Riverside County, CA

243

[Tail Plane Icing  

NASA Technical Reports Server (NTRS)

The Aviation Safety Program initiated by NASA in 1997 has put greater emphasis in safety related research activities. Ice-contaminated-tailplane stall (ICTS) has been identified by the NASA Lewis Icing Technology Branch as an important activity for aircraft safety related research. The ICTS phenomenon is characterized as a sudden, often uncontrollable aircraft nose- down pitching moment, which occurs due to increased angle-of-attack of the horizontal tailplane resulting in tailplane stall. Typically, this phenomenon occurs when lowering the flaps during final approach while operating in or recently departing from icing conditions. Ice formation on the tailplane leading edge can reduce tailplane angle-of-attack range and cause flow separation resulting in a significant reduction or complete loss of aircraft pitch control. In 1993, the Federal Aviation Authority (FAA) and NASA embarked upon a four-year research program to address the problem of tailplane stall and to quantify the effect of tailplane ice accretion on aircraft performance and handling characteristics. The goals of this program, which was completed in March 1998, were to collect aerodynamic data for an aircraft tail with and without ice contamination and to develop analytical methods for predicting the effects of tailplane ice contamination. Extensive dry air and icing tunnel tests which resulted in a database of the aerodynamic effects associated with tailplane ice contamination. Although the FAA/NASA tailplane icing program generated some answers regarding ice-contaminated-tailplane stall (ICTS) phenomena, NASA researchers have found many open questions that warrant further investigation into ICTS. In addition, several aircraft manufacturers have expressed interest in a second research program to expand the database to other tail configurations and to develop experimental and computational methodologies for evaluating the ICTS phenomenon. In 1998, the icing branch at NASA Lewis initiated a second multi-phase research program for tailplane icing (TIP II) to develop test methodologies and tailplane performance and handling qualities evaluation tools. The main objectives of this new NASA/Industry/Academia collaborative research programs were: (1) define and evaluate a sub-scale wind tunnel test methodology for determining tailplane performance degradation due to icing. (2) develop an experimental database of tailplane aerodynamic performance with and without ice contamination for a range of tailplane configurations. Wind tunnel tests were planned with representative general aviation aircraft, i.e., the Learjet 45, and a twin engine low speed aircraft. This report summarizes the research performed during the first year of the study, and outlines the work tasks for the second year.

1997-01-01

244

Helicopter tail rotor noise analyses  

NASA Technical Reports Server (NTRS)

A study was made of helicopter tail rotor noise, particularly that due to interactions with the main rotor tip vortices, and with the fuselage separation mean wake. The tail rotor blade-main rotor tip vortex interaction is modelled as an airfoil of infinite span cutting through a moving vortex. The vortex and the geometry information required by the analyses are obtained through a free wake geometry analysis of the main rotor. The acoustic pressure-time histories for the tail rotor blade-vortex interactions are then calculated. These acoustic results are compared to tail rotor loading and thickness noise, and are found to be significant to the overall tail rotor noise generation. Under most helicopter operating conditions, large acoustic pressure fluctuations can be generated due to a series of skewed main rotor tip vortices passing through the tail rotor disk. The noise generation depends strongly upon the helicopter operating conditions and the location of the tail rotor relative to the main rotor.

George, A. R.; Chou, S. T.

1986-01-01

245

78 FR 60271 - Hollow Dam Power Company; Ampersand Hollow Dam Hydro, LLC; Notice of Application for Transfer of...  

Federal Register 2010, 2011, 2012, 2013

...Dam Power Company; Ampersand Hollow Dam Hydro, LLC; Notice of Application for Transfer...transferor) and Ampersand Hollow Dam Hydro, LLC (transferee) filed an application...Dam Power Company, c/o SilverStreet Hydro, 15 East Silver Street, Westfield,...

2013-10-01

246

Mercury's Dynamic Magnetic Tail  

NASA Technical Reports Server (NTRS)

The Mariner 10 and MESSENGER flybys of Mercury have revealed a magnetosphere that is likely the most responsive to upstream interplanetary conditions of any in the solar system. The source of the great dynamic variability observed during these brief passages is due to Mercury's proximity to the Sun and the inverse proportionality between reconnection rate and solar wind Alfven Mach number. However, this planet's lack of an ionosphere and its small physical dimensions also contribute to Mercury's very brief Dungey cycle, approx. 2 min, which governs the time scale for internal plasma circulation. Current observations and understanding of the structure and dynamics of Mercury's magnetotail are summarized and discussed. Special emphasis will be placed upon such questions as: 1) How much access does the solar wind have to this small magnetosphere as a function of upstream conditions? 2) What roles do heavy planetary ions play? 3) Do Earth-like substorms take place at Mercury? 4) How does Mercury's tail respond to extreme solar wind events such coronal mass ejections? Prospects for progress due to advances in the global magnetohydrodynamic and hybrid simulation modeling and the measurements to be taken by MESSENGER after it enters Mercury orbit on March 18, 2011 will be discussed.

Slavin, James A.

2010-01-01

247

ESTIMATION OF NAVIGATION - DAM DISCHARGE IN ILLINOIS.  

USGS Publications Warehouse

Techniques were used to estimate discharge for the Brandon Road Dam on the Des Plaines River and the Dresden Island, Marseilles, and Starved Rock Dams on the Illinois River in northern Illinois. Tainter gates are operated to regulate streamflow at all dams. Additionally, headgates are used for regulation of the Brandon Road Dam. Stage-discharge, gate-opening relations were developed from a total of 91 discharge measurements that range from 198 to 86,400 cubic feet per second (5. 6 to 2,450 cubic meters per second). Values for discharge coefficients, in equations that express discharge as a function of tailwater depth, headwater depth, and vertical height of gate opening, were determined for conditions of free-orifice, submerged-orifice, free-weir, and submerged-weir flow past a tainter gate.

Weiss, Linda, S.

1987-01-01

248

The Hoover Dam: Lonely Lands Made Fruitful  

NSDL National Science Digital Library

Project designer Janet Haven of the University of Virginia American Studies Program presents the construction of the Hoover Dam as an alternative narrative to the devastation of the Great Depression in her photoessay, The Hoover Dam: Lonely Lands Made Fruitful. Five slide shows created in Flash2 cover the construction from diverting the Colorado River to pouring concrete and adding the final touches to a completed dam. The slide shows are prefaced by historical background, including short essays on topics such as the Dam as the "Machine in the Desert" and the text of Franklin D. Roosevelt's Dedication Speech upon completion, September 30, 1935. Images of maps and plans are linked throughout, and a list of Works Consulted gives concise source descriptions as well as ideas for further reading.

1998-01-01

249

Industrial design of an earth overflow dam  

SciTech Connect

As a result of theoretical and experimental investigations of earth overflow dams of various types and purpose conducted by the author in the past ten years, methods of calculating the stability of protective structures of riprap, reinforcement meshes, gabions, and in situ and precast reinforced concrete were substantiated; the limits of economic applicability of various types of revetments and structures were determined; and new efficient designs of dams and revetments allowing the overflow of water with large discharge intensities were proposed. An earth overflow dam with the downstream slope protected by a precast reinforced-concrete revetment was determined to be the most effective design-technological solution. Both the entire dam or a part of it can be made overflow. The design has been realized on a number of experimental water-management objects which are reviewed.

Pravdivets, Yu.P.

1988-06-01

250

Historic American Engineering Record, Theodore Roosevelt Dam.  

National Technical Information Service (NTIS)

Roosevelt Dam comprises the key structure in one of the first major federally sponsored reclamation project in the West. Authorized as one of the Reclamation Service's first projects in 1903, it continues to store water for agricultural lands, homeowners,...

D. C. Jackson

1992-01-01

251

76 FR 12094 - Whitman River Dam, Inc.  

Federal Register 2010, 2011, 2012, 2013

...2705, 2708. h. Applicant Contact: Robert T. Francis, P.O. Box 145, 10 Tommy Francis Road, Westminster, MA 01473, (978) 874-1010...adjacent to the dam containing one 145-kilowatt turbine generating unit. The proposed project is...

2011-03-04

252

78 FR 62627 - Sam Rayburn Dam Rate  

Federal Register 2010, 2011, 2012, 2013

...Southwestern Power Administration Sam Rayburn Dam Rate AGENCY: Southwestern Power Administration, DOE. ACTION: Notice of Rate Order...placed into effect on an interim basis Rate Order No. SWPA-67, which...

2013-10-22

253

Hydraulic Model Study of Brantley Dam Spillway.  

National Technical Information Service (NTIS)

Hydraulic model studies on the spillway at Brantley Dam in New Mexico confirmed the design of the spillway, slotted bucket energy dissipator, and the spillway tailwater channel. Side piers at the spillway entrance were modified to improve spillway flow; a...

E. R. Zeigler

1987-01-01

254

Dam-breach analysis and flood-inundation mapping for Lakes Ellsworth and Lawtonka near Lawton, Oklahoma  

USGS Publications Warehouse

Dams provide beneficial functions such as flood control, recreation, and reliable water supplies, but they also entail risk: dam breaches and resultant floods can cause substantial property damage and loss of life. The State of Oklahoma requires each owner of a high-hazard dam, which the Federal Emergency Management Agency defines as dams for which failure or misoperation probably will cause loss of human life, to develop an emergency action plan specific to that dam. Components of an emergency action plan are to simulate a flood resulting from a possible dam breach and map the resulting downstream flood-inundation areas. The resulting flood-inundation maps can provide valuable information to city officials, emergency managers, and local residents for planning the emergency response if a dam breach occurs. Accurate topographic data are vital for developing flood-inundation maps. This report presents results of a cooperative study by the city of Lawton, Oklahoma, and the U.S. Geological Survey (USGS) to model dam-breach scenarios at Lakes Ellsworth and Lawtonka near Lawton and to map the potential flood-inundation areas of such dam breaches. To assist the city of Lawton with completion of the emergency action plans for Lakes Ellsworth and Lawtonka Dams, the USGS collected light detection and ranging (lidar) data that were used to develop a high-resolution digital elevation model and a 1-foot contour elevation map for the flood plains downstream from Lakes Ellsworth and Lawtonka. This digital elevation model and field measurements, streamflow-gaging station data (USGS streamflow-gaging station 07311000, East Cache Creek near Walters, Okla.), and hydraulic values were used as inputs for the dynamic (unsteady-flow) model, Hydrologic Engineering Center's River Analysis System (HEC-RAS). The modeled flood elevations were exported to a geographic information system to produce flood-inundation maps. Water-surface profiles were developed for a 75-percent probable maximum flood scenario and a sunny-day dam-breach scenario, as well as for maximum flood-inundation elevations and flood-wave arrival times for selected bridge crossings. Some areas of concern near the city of Lawton, if a dam breach occurs at Lakes Ellsworth or Lawtonka, include water treatment plants, wastewater treatment plants, recreational areas, and community-services offices.

Rendon, Samuel H.; Ashworth, Chad E.; Smith, S. Jerrod

2012-01-01

255

Delineation of subsurface structures using resistivity, VLF and radiometric measurement around a U-tailings pond and its hydrogeological implication  

NASA Astrophysics Data System (ADS)

The hydrogeological characteristics of the uranium mill tailings pond in the vicinity of Jaduguda (Jharkhand, India) were investigated to examine possible contamination and suggest suitable remedial measures, if required. As the hydrogeological characteristics of subsurface geology are closely related to the electrical properties of the subsurface, geophysical measurements using electrical resistivity coupled with Very Low Frequency electromagnetic method and radiation study were used to investigate the geophysical and geological condition of mill tailings in order to characterize the subsurface structures of the tailings pond. The resistivity interpretation depicted the thickness of the soil cover and thickness of tailings in the pond, as well as the depth to the basement. It also suggested the possible flow direction of leachate. It was observed that the resistivity of the top layer decreases in the direction opposite to the dam axis, which in turn, indicated that the groundwater movement occurs in the opposite direction of the dam axis (in the northwest direction). The VLF method depicted the fractures through which groundwater moves, and also showed the current density alignment in the northwest direction at 10 m depth. The radiation measurement showed relatively higher counts in the northwest direction. This correlated well with the resistivity measurement. The current density at a depth of 20 m showed a closed contour suggesting no groundwater movement in the area at this depth, and that high conductivity material was confined to the tailings area only. It was concluded that groundwater moves in opposite direction of the dam axis at shallower depth only. It was found that continuation of fractures do not extend to deeper depths, which suggested that the tailings storage facility at Jaduguda was reasonably safe from any downward contamination.

Banerjee, K. S.; Sharma, S. P.; Sarangi, A. K.; Sengupta, D.

256

The structure of comet tails  

NASA Technical Reports Server (NTRS)

Present models of the plasma tails of comets are described. The interaction of the solar wind with ions from the cometary atmosphere is discussed, and the phenomenon of magnetic reconnection observed in plasma tails is explained. The accomplishments of the ICE mission to the Comet Giacobini-Zinner are summarized, and the tasks and expected contributions from upcoming Soviet, European, and Japanese missions to Comet Halley are addressed.

Brandt, J. C.; Niedner, M. B., Jr.

1986-01-01

257

Financial Risk and Heavy Tails  

Microsoft Academic Search

It is of great importance for those in charge of managing risk to understand how financial asset returns are distributed. Practitioners often assume for convenience that the distribution is normal. Since the 1960s, however, empirical evidence has led many to reject this assumption in favor of various heavy-tailed alternatives. In a heavy-tailed distribution the likelihood that one encounters significant deviations

Brendan O. Bradley; Murad S. Taqqu

2001-01-01

258

Sirenomelia apus with vestigial tail.  

PubMed

Sirenomelia is an exceptionally rare congenital malformation characterized by complete or near complete fusion of lower limbs. A newborn with clinical features of sirenomelia including fused lower limbs in medial position, absent fibula, anal atresia, complete absence of urogenital system (bilateral renal agenesis, absent ureters, urinary bladder, absent internal and external genitalia), a single umbilical artery and a vestigial tail is reported. Association of vestigial tail with sirenomelia is not described in the literature. PMID:15876775

Parikh, Tushar B; Nanavati, Ruchi N; Udani, Rekha H

2005-04-01

259

Numerical modelling of Glacial Lake Outburst Floods using physically based dam-breach models  

NASA Astrophysics Data System (ADS)

The rapid development and instability of moraine-dammed proglacial lakes is increasing the potential for the occurrence of catastrophic Glacial Lake Outburst Floods (GLOFs) in high-mountain regions. Advanced, physically-based numerical dam-breach models represent an improvement over existing methods for the derivation of breach outflow hydrographs. However, significant uncertainty surrounds the initial parameterisation of such models, and remains largely unexplored. We use a unique combination of numerical dam-breach and two-dimensional hydrodynamic modelling, employed with a Generalised Likelihood Uncertainty Estimation (GLUE) framework to quantify the degree of equifinality in dam-breach model output for the reconstruction of the failure of Dig Tsho, Nepal. Monte Carlo analysis was used to sample the model parameter space, and morphological descriptors of the moraine breach were used to evaluate model performance. Equifinal breach morphologies were produced by parameter ensembles associated with differing breach initiation mechanisms, including overtopping waves and mechanical failure of the dam face. The material roughness coefficient was discovered to exert a dominant influence over model performance. Percentile breach hydrographs derived from cumulative distribution function hydrograph data under- or overestimated total hydrograph volume and were deemed to be inappropriate for input to hydrodynamic modelling. Our results support the use of a Total Variation Diminishing solver for outburst flood modelling, which was found to be largely free of numerical instability and flow oscillation. Routing of scenario-specific optimal breach hydrographs revealed prominent differences in the timing and extent of inundation. A GLUE-based method for constructing likelihood-weighted maps of GLOF inundation extent, flow depth, and hazard is presented, and represents an effective tool for communicating uncertainty and equifinality in GLOF hazard assessment. However, future research should focus on the utility of the approach for predictive, as opposed to reconstructive GLOF modelling.

Westoby, M. J.; Brasington, J.; Glasser, N. F.; Hambrey, M. J.; Reynolds, J. M.; Hassan, M. A. A. M.

2014-06-01

260

Geophysical investigations of geology and structure at the Martis Creek Dam, Truckee, California  

NASA Astrophysics Data System (ADS)

A recent evaluation of Martis Creek Dam highlighted the potential for dam failure due to either seepage or an earthquake on nearby faults. In 1972, the U.S. Army Corps of Engineers constructed this earthen dam, located within the Truckee Basin to the north of Lake Tahoe, CA for water storage and flood control. Past attempts to raise the level of the Martis Creek Reservoir to its design level have been aborted due to seepage at locations downstream, along the west dam abutment, and at the base of the spillway. In response to these concerns, the U.S. Geological Survey has undertaken a comprehensive suite of geophysical investigations aimed at understanding the interplay between geologic structure, seepage patterns, and reservoir and groundwater levels. This paper concerns the geologic structure surrounding Martis Creek Dam and emphasizes the importance of a regional-scale understanding to the interpretation of engineering-scale geophysical data. Our studies reveal a thick package of sedimentary deposits interbedded with Plio-Pleistocene volcanic flows; both the deposits and the flows are covered by glacial outwash. Magnetic field data, seismic tomography models, and seismic reflections are used to determine the distribution and chronology of the volcanic flows. Previous estimates of depth to basement (or the thickness of the interbedded deposits) was 100 m. Magnetotelluric soundings suggest that electrically resistive bedrock may be up to 2500 m deep. Both the Polaris Fault, identified outside of the study area using airborne LiDAR, and the previously unnamed Martis Creek Fault, have been mapped through the dam area using ground and airborne geophysics. Finally, as determined by direct-current resistivity imaging, time-domain electromagnetic sounding, and seismic refraction, the paleotopography of the interface between the sedimentary deposits and the overlying glacial outwash plays a principal role both in controlling groundwater flow and in the distribution of the observed seepage.

Bedrosian, Paul A.; Burton, Bethany L.; Powers, Michael H.; Minsley, Burke J.; Phillips, Jeffrey D.; Hunter, Lewis E.

2012-02-01

261

Geophysical investigations of geology and structure at the Martis Creek Dam, Truckee, California  

USGS Publications Warehouse

A recent evaluation of Martis Creek Dam highlighted the potential for dam failure due to either seepage or an earthquake on nearby faults. In 1972, the U.S. Army Corps of Engineers constructed this earthen dam, located within the Truckee Basin to the north of Lake Tahoe, CA for water storage and flood control. Past attempts to raise the level of the Martis Creek Reservoir to its design level have been aborted due to seepage at locations downstream, along the west dam abutment, and at the base of the spillway. In response to these concerns, the U.S. Geological Survey has undertaken a comprehensive suite of geophysical investigations aimed at understanding the interplay between geologic structure, seepage patterns, and reservoir and groundwater levels. This paper concerns the geologic structure surrounding Martis Creek Dam and emphasizes the importance of a regional-scale understanding to the interpretation of engineering-scale geophysical data. Our studies reveal a thick package of sedimentary deposits interbedded with Plio-Pleistocene volcanic flows; both the deposits and the flows are covered by glacial outwash. Magnetic field data, seismic tomography models, and seismic reflections are used to determine the distribution and chronology of the volcanic flows. Previous estimates of depth to basement (or the thickness of the interbedded deposits) was 100 m. Magnetotelluric soundings suggest that electrically resistive bedrock may be up to 2500 m deep. Both the Polaris Fault, identified outside of the study area using airborne LiDAR, and the previously unnamed Martis Creek Fault, have been mapped through the dam area using ground and airborne geophysics. Finally, as determined by direct-current resistivity imaging, time-domain electromagnetic sounding, and seismic refraction, the paleotopography of the interface between the sedimentary deposits and the overlying glacial outwash plays a principal role both in controlling groundwater flow and in the distribution of the observed seepage.

Bedrosian, P. A.; Burton, B. L.; Powers, M. H.; Minsley, B. J.; Phillips, J. D.; Hunter, L. E.

2012-01-01

262

Morphogenesis of the T4 tail and tail fibers  

PubMed Central

Remarkable progress has been made during the past ten years in elucidating the structure of the bacteriophage T4 tail by a combination of three-dimensional image reconstruction from electron micrographs and X-ray crystallography of the components. Partial and complete structures of nine out of twenty tail structural proteins have been determined by X-ray crystallography and have been fitted into the 3D-reconstituted structure of the "extended" tail. The 3D structure of the "contracted" tail was also determined and interpreted in terms of component proteins. Given the pseudo-atomic tail structures both before and after contraction, it is now possible to understand the gross conformational change of the baseplate in terms of the change in the relative positions of the subunit proteins. These studies have explained how the conformational change of the baseplate and contraction of the tail are related to the tail's host cell recognition and membrane penetration function. On the other hand, the baseplate assembly process has been recently reexamined in detail in a precise system involving recombinant proteins (unlike the earlier studies with phage mutants). These experiments showed that the sequential association of the subunits of the baseplate wedge is based on the induced-fit upon association of each subunit. It was also found that, upon association of gp53 (gene product 53), the penultimate subunit of the wedge, six of the wedge intermediates spontaneously associate to form a baseplate-like structure in the absence of the central hub. Structure determination of the rest of the subunits and intermediate complexes and the assembly of the hub still require further study.

2010-01-01

263

Federal Guidelines for Dam Safety: Emergency Action Planning for Dam Owners.  

National Technical Information Service (NTIS)

In April 1977, President Carter issued a memorandum directing the review of federal dam safety activities by an ad hoc panel of recognized experts. In June 1979, the ad hoc interagency committee on dam safety (ICODS) issued its report, which contained the...

2004-01-01

264

Spontaneous Mutations Occur near Dam Recognition Sites in a dam-Escherichia coli Host  

PubMed Central

The mismatch repair system of Escherichia coli K12 removes mispaired bases from DNA. Mismatch repair can occur on either strand of DNA if it lacks N6-methyladenines within 5'-GATC-3' sequences. In hemimethylated heteroduplexes, repair occurs preferentially on the unmethylated strand. If both strands are fully methylated, repair is inhibited. Mutant (dam-) strains of E. coli defective in the adenine methylase that recognizes 5'-GATC-3' sequences (Dam), and therefore defective in mismatch repair, show increased spontaneous mutation rates compared to otherwise isogenic dam+ hosts. We have isolated and characterized 91 independent mutations that arise as a consequence of the Dam- defect in a plasmid-borne phage P22 repressor gene, mnt. The majority of these mutations are A:T?G:C transitions that occur within six base pairs of the two 5'-GATC-3' sequences in the mnt gene. In contrast, the spectrum of mnt- mutations in a dam+ host is comprised of a majority of insertions of IS elements and deletions that do not cluster near Dam recognition sites. These results show that Dam-directed post-replicative mismatch repair plays a significant role in the rectification of potential transition mutations in vivo, and suggest that sequences associated with Dam recognition sites are particularly prone to replication or repair errors.

Carraway, Margaretha; Youderian, Philip; Marinus, M. G.

1987-01-01

265

Heart Failure  

MedlinePLUS

... and empower Americans to make heart-healthy choices. Web Sites with More Information About Heart Failure For ... Educational Materials For Patients For Professionals Related CDC Web Sites Heart Disease Stroke High Blood Pressure Salt ...

266

Testicular failure  

MedlinePLUS

... for testicular failure: Activities that may cause constant, low-level injury to the scrotum , such as riding a ... mineral density and fractures. Blood tests may show low levels of testosterone and high levels of prolactin, FSH , ...

267

Cliff Failure  

USGS Multimedia Gallery

Cliff failure just south of San Gregorio Beach. Slide is 18.3 meters (60 ft) high and displaces approximately 6881 cubic meters (9,000 cubic yards) of material. Large boulders are 1 m (3 ft) across....

2009-01-26

268

SUBAQUEOUS DISPOSAL OF MILL TAILINGS  

SciTech Connect

A study of mill tailings and sulfide minerals was carried out in order to understand their behavior under subaqueous conditions. A series of electrochemical experiments, namely, cyclic voltammetry, electrochemical impedance spectroscopy and galvanic coupling tests were carried out in artificial seawater and in pH 6.8 buffer solutions with chloride and ferric salts. Two mill tailings samples, one from the Kensington Mine, Alaska, and the other from the Holden Mine, Washington, were studied along with pyrite, galena, chalcopyrite and copper-activated sphalerite. SEM analysis of mill tailings revealed absence of sulfide minerals from the Kensington Mine mill tailings, whereas the Holden Mine mill tailings contained approximately 8% pyrite and 1% sphalerite. In order to conduct electrochemical tests, carbon matrix composite (CMC) electrodes of mill tailings, pyrite and galena were prepared and their feasibility was established by conducting a series of cyclic voltammetry tests. The cyclic voltammetry experiments carried out in artificial seawater and pH 6.8 buffer with chloride salts showed that chloride ions play an important role in the redox processes of sulfide minerals. For pyrite and galena, peaks were observed for the formation of chloride complexes, whereas pitting behavior was observed for the CMC electrodes of the Kensington Mine mill tailings. The electrochemical impedance spectroscopy conducted in artificial seawater provided with the Nyquist plots of pyrite and galena. The Nyquist plots of pyrite and galena exhibited an inert range of potential indicating a slower rate of leaching of sulfide minerals in marine environments. The galvanic coupling experiments were carried out to study the oxidation of sulfide minerals in the absence of oxygen. It was shown that in the absence of oxygen, ferric (Fe3+) ions might oxidize the sulfide minerals, thereby releasing undesirable oxidation products in the marine environment. The source of Fe{sup 3{minus}} ions may be attributed to iron-bearing sulfide (and oxide) minerals present in the mill tailings. However, the concentration of available Fe{sup 3{minus}} ions can be reduced by the precipitation of insoluble ferric hydroxides (Fe(OH ){sub 3}) by seawater due to its near neutral pH. In such case, the oxidation of a sulfide mineral is inhibited due to the absence of an oxidizing agent (viz. oxygen and/or Fe{sup 3+} ions). The experiments carried out in this study provided a better understanding of behavior of sulfide minerals and mill tailings in subaqueous conditions and may be useful for further investigation of sulfide minerals and mill tailings in other environments.

Neeraj K. Mendiratta; Roe-Hoan Yoon; Paul Richardson

1999-09-03

269

Does climate have heavy tails?  

NASA Astrophysics Data System (ADS)

When we speak about a distribution with heavy tails, we are referring to the probability of the existence of extreme values will be relatively large. Several heavy-tail models are constructed from Poisson processes, which are the most tractable models. Among such processes, one of the most important are the Lévy processes, which are those process with independent, stationary increments and stochastic continuity. If the random component of a climate process that generates the data exhibits a heavy-tail distribution, and if that fact is ignored by assuming a finite-variance distribution, then there would be serious consequences (in the form, e.g., of bias) for the analysis of extreme values. Yet, it appears that it is an open question to what extent and degree climate data exhibit heavy-tail phenomena. We present a study about the statistical inference in the presence of heavy-tail distribution. In particular, we explore (1) the estimation of tail index of the marginal distribution using several estimation techniques (e.g., Hill estimator, Pickands estimator) and (2) the power of hypothesis tests. The performance of the different methods are compared using artificial time-series by means of Monte Carlo experiments. We systematically apply the heavy tail inference to observed climate data, in particular we focus on time series data. We study several proxy and directly observed climate variables from the instrumental period, the Holocene and the Pleistocene. This work receives financial support from the European Commission (Marie Curie Initial Training Network LINC, No. 289447, within the 7th Framework Programme).

Bermejo, Miguel; Mudelsee, Manfred

2013-04-01

270

Mercury and other trace elements in soils affected by the mine tailing spill in Aznalcóllar (SW Spain)  

Microsoft Academic Search

The Aznalcóllar accident (28th April 1998) occurred because the collapse of the tailing-dam dike of the Aznalcóllar–Los Frailes mines. Soils were affected by a slurry of acidic water loaded with trace elements, finely divided metal sulphides, and materials used in the refining \\/floating process. Studies carried out before and after the soil restoration activities (sludge removal, amending, tilling, and afforestation)

F. Cabrera; J. Ariza; P. Madejón; E. Madejón; J. M. Murillo

2008-01-01

271

Uranium-mill-tailings conditioning technology  

Microsoft Academic Search

Conditioning of uranium mill tailings involves the physico-chemical alteration of tailings to remove or immobilize mobile radionuclides and toxic trace elements before disposal in a repository. The principal immobilization approach under investigation is sntering tailings at high temperatures (1100 to 1200°C) to radically alter the structure of tailings. This thermal stabilization at 1200°C reduced radon emanation power for tailings sands

D. R. Dreesen; E. J. Cokal; P. D. OBrien; E. F. Thode; L. E. Wangen; J. M. Williams

1982-01-01

272

Field verification of reconstructed dam-break flood, Laurel Run, Pennsylvania  

USGS Publications Warehouse

A one-dimensional dam-break flood routing model is verified by using observed data on the flash flood resulting from the failure of Laurel Run Reservoir Dam near Johnstown, Pennsylvania. The model has been developed on the basis of an explicit scheme of the characteristics method with specified time intervals. The model combines one of the characteristic equations with the Rankine-Hugoniot shock equations to trace the corresponding characteristic backward to the known state for solving the depth and velocity of flow at the wave front. The previous version of the model has called for a modification of the method of solution to overcome the computational difficulty at the narrow breach and at any geomorphological constraints where channel geometry changes rapidly. The large reduction in the computational inaccuracies and oscillations was achieved by introducing the actual "storage width" in the equation of continuity and the imaginary "conveyance width" in the equation of motion. Close agreement between observed and computed peak stages at several stations downstream of the dam strongly suggests the validity and applicability of the model. However, small numerical noise appearing in the computed stage and discharge hydrographs at the dam site as well as discrepancy of attenuated peaks in the discharge hydrographs indicate the need for further model improvement.

Chen, Cheng-lung; Armbruster, Jeffrey T.

1979-01-01

273

The Remains of the Dam: What Have We Learned From 10 Years of Dam Removals?  

NASA Astrophysics Data System (ADS)

Over the past 10 years in the U.S., dam removal has evolved from an occasionally implemented, rarely studied, and poorly understood intervention to improve rivers, to a much more frequently accomplished and better studied and understood approach to river restoration. Over that same time period, the numbers and sizes of dams and volumes of sediment released have dramatically increased. By some estimates close to 1000 dams have been removed over the last 100 years, with most of those occurring within the last 10. While most of these are small (less than 15 m high) dams, removals of dams up to 70 m high are presently underway. Releases of sediment associated with these removals over the past 10 years have also increased by close to four orders of magnitude; for example removal of the Elwha River dams in Washington is estimated to release almost 107 m3 of sediment into the lower Elwha River. Given a decade's worth of dam removals and, in some cases, well-orchestrated case studies of the effects of removal on the geomorphology and (to a lesser extent) ecology of rivers, what have we learned? More specifically, where do we now stand with respect to being able to predict the consequences of future dam removals? Drawing on both field examples and numerical models of dam removals in the western U.S., several key lessons stand out. Although every dam removal and river are different, removals initiate very rapid upstream river response and reservoir erosion and evacuation of sediment by various mechanisms that are strongly controlled by grain size of the deposit, volumes of residual sediment relative to total reservoir volume, and style of dam removal (instantaneous versus staged). Erosion of sediment accumulations in fully and partially filled (by sediment) reservoirs proceeds by different trajectories and rates, with full reservoirs releasing sediment primarily by upstream knickpoint retreat while erosion and sediment release in partially-filled reservoirs proceeds by vertical incision and delta progradation. Coarse grained non-cohesive sediment deposits erode by both vertical incision and lateral migration; fine-grained non-cohesive deposits can slump and fail catastrophically by landsliding. The rate of upstream reservoir erosion sets the tempo of downstream river adjustments and sedimentation. Prediction of location of sediment accumulations is bolstered by both 1- and 2-D hydrodynamic models that have proven to be remarkably accurate in predicting the spatial extent and pattern of deposition, but are less accurate with respect to predicting timing and longevity of deposits.Erosion of Marmot coffer dam on the Sandy River, OR following dam breach, October 19, 2007

Grant, G. E.; O'Connor, J. E.; Major, J. J.

2012-12-01

274

Channel changes downstream from a dam  

USGS Publications Warehouse

A flood-control dam was completed during 1979 on Bear Creek, a small tributary stream to the South Platte River in the Denver, Colorado, area. Before and after dam closure, repetitive surveys between 1977 and 1992 at five cross sections downstream of the dam documented changes in channel morphology. During this 15-year period, channel width increased slightly, but channel depth increased by more than 40 percent. Within the study reach, stream gradient decreased and median bed material sizes coarsened from sand in the pools and fine gravel on the riffle to a median coarse gravel throughout the reach. The most striking visual change was from a sparse growth of streamside grasses to a dense growth of riparian woody vegetation.

Hadley, R. F.; Emmett, W. W.

1998-01-01

275

Magnetohydrodynamics of Mira's cometary tail  

NASA Astrophysics Data System (ADS)

Aims: The asymptotic giant-branch, long-period variable star Mira exhibits a 4 parsec long cometary tail in the far-ultraviolet. We address the issue of the origin of this structure and its emission process by simulating the transition of this star from the interstellar medium to the Local Bubble, which is a tenuous, high-pressure medium. Methods: We use the hydrodynamic and the magnetohydrodynamic modules of the PLUTO astrophysical code to carry out our simulations. We study the system without a cooling function, with a simplified exponential cooling function, and with a simplified nonequilibrium cooling function. Results: We find evidence that magnetohydrodynamics constrain the shape of the cometary tail and explain features of its far-ultraviolet emission. We suggest an emission process that involves C0 excitation through inelastic electron collisions and a two-photon continuum to explain the luminosity of Mira's tail.

Gómez, E. A.

2013-10-01

276

Optimizing the dammed: water supply losses and fish habitat gains from dam removal in California.  

PubMed

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic and riparian habitat. Restoring some rivers reaches to free-flowing conditions may restore substantial environmental benefits, but at some economic cost. This study uses a systems analysis approach to preliminarily evaluate removing rim dams in California's Central Valley to highlight promising habitat and unpromising economic use tradeoffs for water supply and hydropower. CALVIN, an economic-engineering optimization model, is used to evaluate water storage and scarcity from removing dams. A warm and dry climate model for a 30-year period centered at 2085, and a population growth scenario for year 2050 water demands represent future conditions. Tradeoffs between hydropower generation and water scarcity to urban, agricultural, and instream flow requirements were compared with additional river kilometers of habitat accessible to anadromous fish species following dam removal. Results show that existing infrastructure is most beneficial if operated as a system (ignoring many current institutional constraints). Removing all rim dams is not beneficial for California, but a subset of existing dams are potentially promising candidates for removal from an optimized water supply and free-flowing river perspective. Removing individual dams decreases statewide delivered water by 0-2282 million cubic meters and provides access to 0 to 3200 km of salmonid habitat upstream of dams. The method described here can help prioritize dam removal, although more detailed, project-specific studies also are needed. Similarly, improving environmental protection can come at substantially lower economic cost, when evaluated and operated as a system. PMID:24594701

Null, Sarah E; Medellín-Azuara, Josué; Escriva-Bou, Alvar; Lent, Michelle; Lund, Jay R

2014-04-01

277

Migration of arsenic from old tailings ponds-A case study on the King Edward Mine, Cornwall, UK  

SciTech Connect

A methodology is presented to study the physico-chemical processes in old tailings ponds using an array of analytical-physical chemistry approaches. A case study was conducted on the sorption/desorption behaviour of arsenic in tailings pond 2406, at the King Edward Mine (KEM) in Cornwall, UK. The tailings pond was in operation from approximately 1907 to 1921. The methodology involves two principal stages: (1) sequential extraction followed by subsequent arsenic species determination to characterise the material with regards to the association of arsenic with soil phases and identification of As (III/V) in the easily accessible soil phase; (2) batch contacting/equilibrating the tailings pond material with As(III/V), followed by a similar procedure as in stage 1 to establish the material's As(III/V) phase distribution kinetics/thermodynamics. By extrapolating the data from present day samples we infer past and future elemental mobility. From this study it is concluded that adsorption and desorption from tailings material is a rapid process for the most unstable soil phases (non-specific and specific) and a slow process for the more stable phases (poorly crystalline and well crystalline). The hypothetical application of this conclusion to the tailings from dam 2406 is that, during the initial phases of the dam's creation (ca. 100 years ago), when arsenic was both in solution and bound to mineralogical components, arsenic must have dispersed into the environment as a result of slow As(V) adsorption/phase distribution processes. Aging of the tailings material sees the movement of the arsenic to the more stable soil phases, producing a situation that is seen at present day.

Beeston, Michael Philip [National Institute of Chemistry (Kiribati), Hajdrihova 19, SI-1001 Ljubljana (Slovenia); University of Exeter in Cornwall (UEC), Tremough Campus, TR10 9EZ Penryn, Cornwall (United Kingdom)], E-mail: Michael.Beeston@ki.si; Tuen van Elteren, Johannes [National Institute of Chemistry (Kiribati), Hajdrihova 19, SI-1001 Ljubljana (Slovenia); Slejkovec, Zdenka [Jozef Stefan Institute (JSI), Jamova 39, SI-1000 Ljubljana (Slovenia); Glass, Hylke Jan [University of Exeter in Cornwall (UEC), Tremough Campus, TR10 9EZ Penryn, Cornwall (United Kingdom)

2008-09-15

278

Panoramic view from bluff south of Grand Coulee Dam; this ...  

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

Panoramic view from bluff south of Grand Coulee Dam; this segment of the panorama shows the westernmost extend of Franklin D. Roosevelt Lake and part of Grand Coulee Dam, looking north. - Columbia Basin Project, Grand Coulee, Grant County, WA

279

4. Aerial view of Whitsett intake (lower right), Parker Dam ...  

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

4. Aerial view of Whitsett intake (lower right), Parker Dam and village (left), Gene Wash Reservoir, Gene Pump Plant and village (right). - Parker Dam, Spanning Colorado River between AZ & CA, Parker, La Paz County, AZ

280

55. Downstream face of diversion dam looking northwest. Photographer Mark ...  

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

55. Downstream face of diversion dam looking northwest. Photographer Mark Durben, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

281

7. Aggregate operations downstream from dam. Photographer unknown, March 1924. ...  

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

7. Aggregate operations downstream from dam. Photographer unknown, March 1924. Source: Salt River Project. - Mormon Flat Dam, On Salt River, Eastern Maricopa County, east of Phoenix, Phoenix, Maricopa County, AZ

282

49. Downstream face of Humbug Creek Diversion Dam with sluice ...  

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

49. Downstream face of Humbug Creek Diversion Dam with sluice opening at center. Photographer James Eastwood, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

283

44. Reinforcement construction to Pleasant Dam. Photographer unknown, 1935. Source: ...  

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

44. Reinforcement construction to Pleasant Dam. Photographer unknown, 1935. Source: Huber Collection, University of California, Berkeley, Water Resources Library. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

284

70. Downstream view of Waddell Dam spillway and taintor gates. ...  

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

70. Downstream view of Waddell Dam spillway and taintor gates. Photographer Mark Durben. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

285

56. Upstream face of diversion dam looking east. Headgates are ...  

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

56. Upstream face of diversion dam looking east. Headgates are partially visible at far left. Photographer Mark Durben, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

286

40. Reservoir behind Pleasant Dam, looking downstream, spillway is at ...  

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

40. Reservoir behind Pleasant Dam, looking downstream, spillway is at right. Photographer unknown, c. late 1920s. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

287

45. Reinforcement work to buttresses at Pleasant Dam. Support work ...  

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

45. Reinforcement work to buttresses at Pleasant Dam. Support work for roadway and roadway visible. Photographer unknown, 1935. Source: Huber Collection. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

288

60. Waddell Dam in relation and spillway tailrace. Photographer Mark ...  

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

60. Waddell Dam in relation and spillway tailrace. Photographer Mark Durben, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

289

39. Pleasant Dam from east abutment with spillway visible at ...  

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

39. Pleasant Dam from east abutment with spillway visible at center. Photographer unknown, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

290

1. Site of Mormon Flat Dam looking upstream. Photographer unknown, ...  

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

1. Site of Mormon Flat Dam looking upstream. Photographer unknown, 1923. Source: Salt River Project. - Mormon Flat Dam, On Salt River, Eastern Maricopa County, east of Phoenix, Phoenix, Maricopa County, AZ

291

57. Downstream side of left section of diversion dam. Photographer ...  

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

57. Downstream side of left section of diversion dam. Photographer Mark Durben, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

292

50. Upstream face of Humbug Creek Diversion Dam showing sluice ...  

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

50. Upstream face of Humbug Creek Diversion Dam showing sluice opening. Photographer James Eastwood, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

293

Corrective Action Study Geotechnical Issues at Salmon Lake Dam.  

National Technical Information Service (NTIS)

The Modification Decision Analysis (MDA) decision memorandum indicated that Salmon Lake Dam has dam safety deficiencies caused by the Maximum Credible earthquake (MCE) and the Probable Maximum Flood (PMF) (1)1. This technical memorandum (TM) presents the ...

R. L. Torres R. W. Luehring

1996-01-01

294

Nonlinear Earthquake Response of Concrete Gravity Dam Systems.  

National Technical Information Service (NTIS)

The earthquake response of concrete gravity dam systems is investigated with emphasis on the nonlinear behavior associated with tensile concrete cracking and water cavitation. A single dam-monolith is considered and is assumed to respond independently as ...

B. El-Aidi

1988-01-01

295

1. Salmon Creek Diversion Dam, weir (to left), sand and ...  

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

1. Salmon Creek Diversion Dam, weir (to left), sand and silt sluice gate (center), main canal headworks (to right), view to northwest - Salmon Creek Diversion Dam, Salmon Creek, Okanogan, Okanogan County, WA

296

2. Salmon Creek Diversion Dam, overview, diversion weir center foreground, ...  

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

2. Salmon Creek Diversion Dam, overview, diversion weir center foreground, headworks overflow weir to center left, view to east - Salmon Creek Diversion Dam, Salmon Creek, Okanogan, Okanogan County, WA

297

12. LOCK, ELECTRICAL SYSTEM, LOCK, DAM, AND NAVIGATION LIGHTING UNITS ...  

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

12. LOCK, ELECTRICAL SYSTEM, LOCK, DAM, AND NAVIGATION LIGHTING UNITS (October 1935) - Mississippi River 9-Foot Channel Project, Lock & Dam No. 18, Upper Mississippi River, Gladstone, Henderson County, IL

298

76. LOCK, ELECTRICAL SYSTEM, LOCK, DAM AND NAVIGATION LIGHTING UNITS. ...  

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

76. LOCK, ELECTRICAL SYSTEM, LOCK, DAM AND NAVIGATION LIGHTING UNITS. February 1938 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 17, Upper Mississippi River, New Boston, Mercer County, IL

299

2. VIEW EAST OF HEADGATES AT SPOOL DAM; DRAIN GATE ...  

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

2. VIEW EAST OF HEADGATES AT SPOOL DAM; DRAIN GATE MECHANISM AND DAM EDGE AT RIGHT - Willimantic Linen Company, Mill No. 1, Immediately West of South Main Street, North Bank of Willimantic River, Windham, Windham County, CT

300

4. INTERIOR OF THE VALVE HOUSE, DIABLO DAM, SHOWING CONTROLS ...  

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

4. INTERIOR OF THE VALVE HOUSE, DIABLO DAM, SHOWING CONTROLS FOR RELIEF VALVE, 1989. - Skagit Power Development, Diablo Dam, On Skagit River, 6.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

301

19. View of low crib dam, headworks, and tramway above ...  

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

19. View of low crib dam, headworks, and tramway above dam, looking southeast. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

302

117. Maricopa Dam Water System, Electric Transmission Lines, Catwalk, Derrick ...  

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

117. Maricopa Dam Water System, Electric Transmission Lines, Catwalk, Derrick at Elev. +65. October 15, 1934. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

303

VIEW FROM NORTH BANK LOOKING SOUTHWEST SHOWING DAM CREST, FISH ...  

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

VIEW FROM NORTH BANK LOOKING SOUTHWEST SHOWING DAM CREST, FISH ATTRACTION FLOW STRUCTURE (LEFT) AND WASTE FLOW GATE OUTLET (RIGHT) - Trout Creek Dam, River Mile 1.8 on Trout Creek, Carson, Skamania County, WA

304

View of Lake Sabrina Dam upstream face from ridge showing ...  

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

View of Lake Sabrina Dam upstream face from ridge showing spillway at lower right of photo, view southwest - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

305

23. INTAKE DIVERSION DAM UNDER CONSTRUCTION, FACING NORTHWEST AND DOWNSTREAM ...  

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

23. INTAKE DIVERSION DAM UNDER CONSTRUCTION, FACING NORTHWEST AND DOWNSTREAM Photographer: Walter J. Lubken, September 17, 1906 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

306

78. POWER CANAL DIVERSION DAM, EXISTING STRUCTURE Courtesy of Dept. ...  

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

78. POWER CANAL DIVERSION DAM, EXISTING STRUCTURE Courtesy of Dept. of the Interior, Bureau of Reclamation, Salt River Project - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

307

21. THE WHITNEY CONSTRUCTION CAMP AT THE DIVERSION DAM, FACING ...  

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

21. THE WHITNEY CONSTRUCTION CAMP AT THE DIVERSION DAM, FACING SOUTH. WOOD BURNING PLANT AT RIGHT, INTAKE GATES AT CENTER LEFT. Photographer: Walter J. Lubken, June 13, 1906 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

308

1. TEMPORARY POWER HOUSE AT ROOSEVELT DAM. TRAMWAY LINES CAN ...  

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

1. TEMPORARY POWER HOUSE AT ROOSEVELT DAM. TRAMWAY LINES CAN BE SEEN AT TOP OF PHOTOGRAPH Photographer: Walter J. Lubken, May 10, 1906 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

309

72. ARRANGEMENT OF SLUICE GATES AND HOISTS, DIVERSION DAM ...  

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

72. ARRANGEMENT OF SLUICE GATES AND HOISTS, DIVERSION DAM - POWER CANAL Courtesy of U.S.G.S., Reclamation Service, Salt River Project - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

310

73. GENERAL ASSEMBLY OF MECHANISM, FOR OPERATING DIVERSION DAM SLUICE ...  

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

73. GENERAL ASSEMBLY OF MECHANISM, FOR OPERATING DIVERSION DAM SLUICE GATES Courtesy of U.S.R.S., Salt River Project - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

311

27. Evening view of downstream face of Pleasant Dam under ...  

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

27. Evening view of downstream face of Pleasant Dam under construction. Part of construction camp housing is visible in foreground. Photographer unknown, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

312

"No. 169. Congressional party visiting the roller crest dam in ...  

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

"No. 169. Congressional party visiting the roller crest dam in 1915. Dedication." - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

313

1. OVERALL VIEW OF UPSTREAM FACE OF DAM; SPILLWAY IN ...  

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

1. OVERALL VIEW OF UPSTREAM FACE OF DAM; SPILLWAY IN FOREGROUND, LOCK IN BACKGROUND ON NORTH RIVER BANK. VIEW TO NORTH. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

314

GENERAL AERIAL VIEW TO SOUTH OF ELWHA DAM AND POWERHOUSE ...  

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

GENERAL AERIAL VIEW TO SOUTH OF ELWHA DAM AND POWERHOUSE WITH NORTH END OF RESERVOIR. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

315

GENERAL AERIAL VIEW OF LAKE ALDWELL AND ELWHA DAM AND ...  

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

GENERAL AERIAL VIEW OF LAKE ALDWELL AND ELWHA DAM AND POWERHOUSE, WITH STRAIT OF JUAN DE FUCA TO THE NORTH. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

316

22. TWIN FALLS MAIN CANAL HEADWORKS WITH MILNER DAM IN ...  

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

22. TWIN FALLS MAIN CANAL HEADWORKS WITH MILNER DAM IN DISTANCE; LOOKING EAST. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

317

23. TWIN FALLS MAIN CANAL HEADWORKS WITH MILNER DAM IN ...  

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

23. TWIN FALLS MAIN CANAL HEADWORKS WITH MILNER DAM IN DISTANCE; LOOKING NORTHEAST. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

318

5. View of upper dam side sluice taken from east ...  

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

5. View of upper dam side sluice taken from east bank of Millstone Creek. VIEW WEST - Loleta Recreation Area, Upper Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

319

3. Side view of upper dam overspill, taken from east ...  

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

3. Side view of upper dam overspill, taken from east bank of Millstone Creek. VIEW WEST - Loleta Recreation Area, Upper Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

320

1. East side of lower dam shown with water level ...  

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

1. East side of lower dam shown with water level dropped. VIEW WEST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

321

4. Side of view of upper dam overspill, taken from ...  

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

4. Side of view of upper dam overspill, taken from west bank of Millstone Creek, VIEW EAST - Loleta Recreation Area, Upper Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

322

3. POOL, DAM, AND INTAKE TO PIPELINE LEADING TO FISH ...  

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

3. POOL, DAM, AND INTAKE TO PIPELINE LEADING TO FISH WHEEL, LOOKING WEST-NORTHWEST. - Santa Ana River Hydroelectric System, Bear Creek Diversion Dam & Confluence Pool, Redlands, San Bernardino County, CA

323

Interior of dam, showing one of the ten bays, looking ...  

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

Interior of dam, showing one of the ten bays, looking west through arched openings along the center of the dam. - Robert B. Morse Water Filtration Plant, 10700 and 10701 Columbia Pike, Silver Spring, Montgomery County, MD

324

1. SNAKE RIVER VALLEY IRRIGATION DISTRICT DAM, VIEW OF NORTH ...  

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

1. SNAKE RIVER VALLEY IRRIGATION DISTRICT DAM, VIEW OF NORTH ELEVATION OF INTAKE ON EAST SIDE OF DAM - Snake River Valley Irrigation District, East Side of Snake River (River Mile 796), Shelley, Bingham County, ID

325

7. ISLAND PLANT AND HORSESHOE DAM FROM WEST BANK (negative ...  

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

7. ISLAND PLANT AND HORSESHOE DAM FROM WEST BANK (negative reversed) - American Falls Water, Power & Light Company, Island Power Plant, Snake River, below American Falls Dam, American Falls, Power County, ID

326

20. HORSESHOE DAM LOOKING EAST WITH UPPER END DEMOLISHED FOR ...  

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

20. HORSESHOE DAM LOOKING EAST WITH UPPER END DEMOLISHED FOR NEW SPILLWAY (negative reversed) - American Falls Water, Power & Light Company, Island Power Plant, Snake River, below American Falls Dam, American Falls, Power County, ID

327

1. OVERALL VIEW SHOWING FACE OF CONCRETE GRAVITY DAM AND ...  

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

1. OVERALL VIEW SHOWING FACE OF CONCRETE GRAVITY DAM AND FISH LADDER, LOOKING SOUTHWEST (UPSTREAM) FROM SNORE OPPOSITE FISH LADDER - Van Arsdale Dam, South Fork of Eel River, Ukiah, Mendocino County, CA

328

59. AERIAL VIEW OF OWYHEE DAM SHOWING RINGGATE SPILLWAY. VIEW ...  

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

59. AERIAL VIEW OF OWYHEE DAM SHOWING RING-GATE SPILLWAY. VIEW TO NORTHEAST. Aerial photo by Glade Walker, U.S. Bureau of Reclamation, Pacific Northwest Region, September 29, 1989. - Owyhee Dam, Across Owyhee River, Nyssa, Malheur County, OR

329

32. Otter Lake Dam. View from downstream show how the ...  

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

32. Otter Lake Dam. View from downstream show how the dam blends into its environment. Looking east-northeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

330

Dam-Break Flood Analysis Upper Hurricane Reservoir, Hartford, Vermont.  

National Technical Information Service (NTIS)

The purpose of this study was to determine the downstream hazard potential of the Upper Hurricane Reservoir in Hartford, Vermont. The work was completed for the Vermont Department of Environmental Conservation's Dam Safety Program. Various dam break flood...

S. Acone C. Hatfield

1995-01-01

331

2. EASTSIDE RESERVOIR UNDER CONSTRUCTION LOOKING WEST WITH EAST DAM ...  

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

2. EASTSIDE RESERVOIR UNDER CONSTRUCTION LOOKING WEST WITH EAST DAM IN MIDDLE GROUND, WEST DAM IN DISTANCE. - Eastside Reservoir, Diamond & Domenigoni Valleys, southwest of Hemet, Hemet, Riverside County, CA

332

2. SOUTHEAST VIEW OF BIG TUJUNGA DAM SHOWING THE LEFT ...  

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

2. SOUTHEAST VIEW OF BIG TUJUNGA DAM SHOWING THE LEFT ABUTMENT WITH THE CONTROL HOUSE IN THE BACKGROUND. PHOTO TAKEN FROM THE ACCESS ROAD. - Big Tujunga Dam, 809 West Big Tujunga Road, Sunland, Los Angeles County, CA

333

6. EASTERLY VIEW OF BIG DALTON DAM SHOWING THE SHELTER ...  

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

6. EASTERLY VIEW OF BIG DALTON DAM SHOWING THE SHELTER HOUSE IN THE BACKGROUND. PHOTO TAKEN FROM THE ACCESS ROAD LEADING TO THE CONTROL HOUSE. - Big Dalton Dam, 2600 Big Dalton Canyon Road, Glendora, Los Angeles County, CA

334

34. DOWNSTREAM VIEW OF COOLIDGE DAM COMPLETED. POWER HOUSE, INTAKE ...  

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

34. DOWNSTREAM VIEW OF COOLIDGE DAM COMPLETED. POWER HOUSE, INTAKE TOWERS, WEST SPILLWAY CHANNEL AND DECORATIVE EAGLES ALL CLEARLY VISIBLE, c. 1928 - Coolidge Dam, Gila River, Peridot, Gila County, AZ

335

Field Experiences in Improving Water Quality Downstream from Dams.  

National Technical Information Service (NTIS)

Recent experiences by the Tennessee Valley Authority in improving water quality and fish habitat downstream from dams are presented. At Douglas Dam, floating pumps near the surface of the large, thermally stratified reservoir are being used to move surfac...

C. E. Bohac E. D. Harshbarger M. H. Mobley

2009-01-01

336

68. LITTLE ROCK AND PALMDALE IRRIGATION DISTRICT, LITTLE ROCK DAM: ...  

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

68. LITTLE ROCK AND PALMDALE IRRIGATION DISTRICT, LITTLE ROCK DAM: STRESS SHEET, SHEET 4; MAY, 1918. Littlerock Water District files. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

337

71. PALMDALE WATER COMPANY, EASTWOOD MULTIPLEARCHED DAM: STRESS SHEET, SHEET ...  

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

71. PALMDALE WATER COMPANY, EASTWOOD MULTIPLE-ARCHED DAM: STRESS SHEET, SHEET 3; DECEMBER 20, 1918. Littlerock Water District files. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

338

2. DOWNSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING WEST. ...  

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

2. DOWNSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING WEST. - Washington Water Power Company Post Falls Power Plant, South Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

339

1. UPSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING EAST. ...  

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

1. UPSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING EAST. - Washington Water Power Company Post Falls Power Plant, South Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

340

1. DIVERSION GATE AT SPILLWAY, NORTH CANAL DAM (DIVERSION GATE ...  

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

1. DIVERSION GATE AT SPILLWAY, NORTH CANAL DAM (DIVERSION GATE FEEDING PIPE AT LOWER RIGHT), VIEW TO SOUTHWEST. - North Canal Dam & Diversion Canals, Deschutes Reclamation & Irrigation Company Canal, Empire Boulevard vicinity, Bend, Deschutes County, OR

341

10. DETAIL OF NONOVERFLOW SECTION OF DAM SHOWING PENSTOCK OF ...  

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

10. DETAIL OF NON-OVERFLOW SECTION OF DAM SHOWING PENSTOCK OF SUBMERSIBLE TURBINE-GENERATOR - Middle Creek Hydroelectric Dam, On Middle Creek, West of U.S. Route 15, 3 miles South of Selinsgrove, Selinsgrove, Snyder County, PA

342

7. Detail view of reinforced concrete archrings comprising dam's upstream ...  

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

7. Detail view of reinforced concrete arch-rings comprising dam's upstream face. Impressions of the wooden formwork used in construction are visible in the concrete. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

343

29. VIEW NORTHWEST ON SHELTON SIDE OF DAM DURING DEWATERING. ...  

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

29. VIEW NORTHWEST ON SHELTON SIDE OF DAM DURING DEWATERING. SHELTON GATEHOUSE IN LEFT CENTER. - Ousatonic Water Power Company, Dam & Canals, CT Routes 34 & 108, 1 mile North of Derby-Shelton Bridge, Derby, New Haven County, CT

344

Magnetospheric Substorms and Tail Dynamics  

NASA Technical Reports Server (NTRS)

This grant funded several studies of magnetospheric substorms and their effect on the dynamics of the earth's geomagnetic tail. We completed an extensive study of plasmoids, plasma/magnetic field structures that travel rapidly down the tail, using data from the ISEE 3 and IMP 8 spacecraft. This study formed the PhD thesis of Mark Moldwin. We found that magnetically plasmoids are better described as flux-ropes (twisted magnetic flux tubes) rather than plasma bubbles, as had been generally regarded up to that point (Moldwin and Hughes, 1990; 1991). We published several examples of plasmoids observed first in the near tail by IMP 8 and later in the distant tail by ISEE 3, confirming their velocities down tail. We showed how the passage of plasmoids distorts the plasma sheet. We completed the first extensive statistical survey of plasmoids that showed how plasmoids evolve as they move down tail from their formation around 30 RE to ISEE 3 apogee at 240 RE. We established a one-to-one correspondence between the observation of plasmoids in the distant tail and substorm onsets at earth or in the near tail. And we showed that there is a class of plasmoid-like structures that move slowly earthward, especially following weak substorms during northward IMF. Collectively this work constituted the most extensive study of plasmoids prior to the work that has now been done with the GEOTAIL spacecraft. Following our work on plasmoids, we turned our attention to signatures of substorm onset observed in the inner magnetosphere near geosynchronous orbit, especially signatures observed by the CRRES satellite. Using data from the magnetometer, electric field probe, plasma wave instrument, and low energy plasma instrument on CRRES we were able to better document substorm onsets in the inner magnetosphere than had been possible previously. Detailed calculation of the Poynting flux showed energy exchange between the magnetosphere and ionosphere, and a short burst of tailward convective flow just prior to onset, suggesting the active role of the ionosphere in the onset process, and adding credibility to the ballooning instability theory of substorm onset. This grant also supported a number of other substorm studies and reviews. These are represented by the list of publications and meeting presentations resulting out of this grant.

Hughes, W. Jeffrey

1998-01-01

345

2. View of the southern twothirds of the dam showing ...  

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

2. View of the southern two-thirds of the dam showing the Glens Falls Bridge over the Hudson River on the left, the Niagara Mohawk Power Corporation penstocks and inktake structure at the southeast corner of the dam, and the dam itself. The Finch Pruyn & Company Forebay is the foreground. Facing south. - Glens Falls Dam, 100' to 450' West of U.S. Route 9 Bridge Spanning Hudson River, Glens Falls, Warren County, NY

346

Evaluating the effects of dam breach methodologies on Consequence Estimation through Sensitivity Analysis  

NASA Astrophysics Data System (ADS)

Dam breach modeling often includes application of models that are sophisticated, yet computationally intensive to compute flood propagation at high temporal and spatial resolutions. This results in a significant need for computational capacity that requires development of newer flood models using multi-processor and graphics processing techniques. Recently, a comprehensive benchmark exercise titled the 12th Benchmark Workshop on Numerical Analysis of Dams, is organized by the International Commission on Large Dams (ICOLD) to evaluate the performance of these various tools used for dam break risk assessment. The ICOLD workshop is focused on estimating the consequences of failure of a hypothetical dam near a hypothetical populated area with complex demographics, and economic activity. The current study uses this hypothetical case study and focuses on evaluating the effects of dam breach methodologies on consequence estimation and analysis. The current study uses ICOLD hypothetical data including the topography, dam geometric and construction information, land use/land cover data along with socio-economic and demographic data. The objective of this study is to evaluate impacts of using four different dam breach methods on the consequence estimates used in the risk assessments. The four methodologies used are: i) Froehlich (1995), ii) MacDonald and Langridge-Monopolis 1984 (MLM), iii) Von Thun and Gillete 1990 (VTG), and iv) Froehlich (2008). To achieve this objective, three different modeling components were used. First, using the HEC-RAS v.4.1, dam breach discharge hydrographs are developed. These hydrographs are then provided as flow inputs into a two dimensional flood model named Flood2D-GPU, which leverages the computer's graphics card for much improved computational capabilities of the model input. Lastly, outputs from Flood2D-GPU, including inundated areas, depth grids, velocity grids, and flood wave arrival time grids, are input into HEC-FIA, which provides the consequence assessment for the solution to the problem statement. For the four breach methodologies, a sensitivity analysis of four breach parameters, breach side slope (SS), breach width (Wb), breach invert elevation (Elb), and time of failure (tf), is conducted. Up to, 68 simulations are computed to produce breach hydrographs in HEC-RAS for input into Flood2D-GPU. The Flood2D-GPU simulation results were then post-processed in HEC-FIA to evaluate: Total Population at Risk (PAR), 14-yr and Under PAR (PAR14-), 65-yr and Over PAR (PAR65+), Loss of Life (LOL) and Direct Economic Impact (DEI). The MLM approach resulted in wide variability in simulated minimum and maximum values of PAR, PAR 65+ and LOL estimates. For PAR14- and DEI, Froehlich (1995) resulted in lower values while MLM resulted in higher estimates. This preliminary study demonstrated the relative performance of four commonly used dam breach methodologies and their impacts on consequence estimation.

Kalyanapu, A. J.; Thames, B. A.

2013-12-01

347

Heart Failure  

Microsoft Academic Search

Summary Management 1. When performing the initial evaluation of a patient diagnosed with heart failure (HF), you should assess the following: a. The severity of the symptoms of impaired cardiac function (e.g., dyspnea on exertion, paroxysmal nocturnal dyspnea, orthopnea, fatigue, and leg edema) b. Evidence for risk factors strongly associated with HF: ischemic heart disease, hypertension, diabetes, valvular heart disease

William Lewis; Jim Nuovo

348

33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.  

Code of Federal Regulations, 2010 CFR

...Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. 208.19 Section...Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. The Secretary...River (entering the Colorado River between Lakes Inks and Lyndon B....

2010-07-01

349

33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.  

Code of Federal Regulations, 2010 CFR

...Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. 208.19 Section...Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex. The Secretary...River (entering the Colorado River between Lakes Inks and Lyndon B....

2009-07-01

350

33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.  

Code of Federal Regulations, 2012 CFR

...Mansfield Dam and Lake Travis), Colorado River, Tex. 208.19 Section 208.19...Mansfield Dam and Lake Travis), Colorado River, Tex. The Secretary of the Interior, through his agent, the Lower Colorado River Authority (LCRA) shall operate the...

2012-07-01

351

33 CFR 208.19 - Marshall Ford Dam and Reservoir (Mansfield Dam and Lake Travis), Colorado River, Tex.  

Code of Federal Regulations, 2011 CFR

...Mansfield Dam and Lake Travis), Colorado River, Tex. 208.19 Section 208.19...Mansfield Dam and Lake Travis), Colorado River, Tex. The Secretary of the Interior, through his agent, the Lower Colorado River Authority (LCRA) shall operate the...

2011-07-01

352

76 FR 34799 - Permanent Dam Safety Modification at Cherokee, Fort Loudoun, Tellico, and Watts Bar Dams, TN  

Federal Register 2010, 2011, 2012, 2013

...alternatives for permanent modifications to the existing dam facilities...solutions for dam safety modifications to replace interim modifications that were implemented at...assumes the most extreme weather event reasonably...

2011-06-14

353

20. VIEW FROM DOWNSTREAM SIDE OF DAM SHOWING BUTTS OF ...  

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

20. VIEW FROM DOWNSTREAM SIDE OF DAM SHOWING BUTTS OF LOGS PROJECTING BETWEEN CROSS LOGS. FREQUENTLY WHOLE TREES WERE USED IN CONSTRUCTING THESE DAMS. THE BRANCHES WERE PLACED UPSTREAM AND COVERED WITH EARTH AND STONE TO ANCHOR THEM. Photographed November 6, 1935. - Forge Creek Dam-John Cable Mill, Townsend, Blount County, TN

354

LOCK, DOG HOUSE, CONTROL STATION, DAM GATE, MANEUVER BOAT No. ...  

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

LOCK, DOG HOUSE, CONTROL STATION, DAM GATE, MANEUVER BOAT No. 1, AND DAM. NOTE LOWER LOCK GATE IN FOREGROUND. LOOKING NORTH NORTHEAST. - Illinois Waterway, La Grange Lock and Dam, 3/4 mile south of Country 795N at Illinois River, Versailles, Brown County, IL

355

77 FR 50493 - Sam Rayburn Dam Project Power Rate  

Federal Register 2010, 2011, 2012, 2013

...Southwestern Power Administration Sam Rayburn Dam Project Power Rate AGENCY: Southwestern...SUMMARY: The current Sam Rayburn Dam Project rate was approved by the Federal...with the Sam Rayburn and Robert D. Willis Dams, two Corps projects that are isolated...

2012-08-21

356

75 FR 34476 - Glen Canyon Dam Adaptive Management Work Group  

Federal Register 2010, 2011, 2012, 2013

...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group AGENCY...renewing the charter for the Glen Canyon Dam Adaptive Management Work Group. The purpose...respect to the operation of Glen Canyon Dam and the exercise of other authorities...

2010-06-17

357

75 FR 50777 - Minidoka Dam Spillway Replacement, Minidoka County, ID  

Federal Register 2010, 2011, 2012, 2013

...Reclamation [INT-FES 10-43] Minidoka Dam Spillway Replacement, Minidoka County...prepared a FEIS on the proposed Minidoka Dam Spillway Replacement. The U.S. Fish...be submitted electronically to minidoka_dam_eis@usbr.gov. FOR FURTHER...

2010-08-17

358

22. THE DIVERSION DAM UNDER CONSTRUCTION AT THE INTAKE OF ...  

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

22. THE DIVERSION DAM UNDER CONSTRUCTION AT THE INTAKE OF THE SALT RIVER POWER CANAL, SHOWING COMPLETED APRON OF DAM IN MAIN CHANNEL OF RIVER BED. Photographer: Walter J. Lubken, October 17, 1906 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

359

2. VIEW SHOWING UPSTREAM FACE OF DAM, WITH UPRIGHT (INOPERABLE) ...  

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

2. VIEW SHOWING UPSTREAM FACE OF DAM, WITH UPRIGHT (INOPERABLE) OUTLET GATE, LOOKING WEST - High Mountain Dams in Upalco Unit, Water Lily Lake Dam, Ashley National Forest, 1.1 miles Northeast of Swift Creek Campground, Mountain Home, Duchesne County, UT

360

3. VIEW SHOWING UPSTREAM FACE OF DAM, WITH UPRIGHT (INOPERABLE) ...  

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

3. VIEW SHOWING UPSTREAM FACE OF DAM, WITH UPRIGHT (INOPERABLE) OUTLET GATE, LOOKING EAST - High Mountain Dams in Upalco Unit, Water Lily Lake Dam, Ashley National Forest, 1.1 miles Northeast of Swift Creek Campground, Mountain Home, Duchesne County, UT

361

2. UPSTREAM SIDE OF DAM AND BRIDGE WITH ABANDONED SAN ...  

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

2. UPSTREAM SIDE OF DAM AND BRIDGE WITH ABANDONED SAN TAN FLOOD-WATER HEADGATE IN FOREGROUND. TAKEN FROM NORTH END OF DAM - San Carlos Irrigation Project, Sacaton Dam & Bridge, Gila River, T4S R6E S12/13, Coolidge, Pinal County, AZ

362

1. East apron upper dam with water flowing over overspill. ...  

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

1. East apron upper dam with water flowing over overspill. Photograph taken from crest of lower dam in foreground). VIEW WEST - Loleta Recreation Area, Upper Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

363

1 NONLINEAR SEISMIC ANALYSIS OF SWEETWATER MAIN DAM  

Microsoft Academic Search

This paper presents the results of advanced seismic analysis of Sweetwater Main Dam (Sweetwater Dam), a 118-foot-high curved concrete gravity dam owned and operated by Sweetwater Authority, Chula Vista, CA. Linear-elastic finite element analysis of the maximum cross-section was performed using the \\

Gilles Bureau; G. E. Scott; W. McClelland

364

1. VIEW OF DOWNSTREAM SIDE OF DIVERSION DAM ON THE ...  

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

1. VIEW OF DOWNSTREAM SIDE OF DIVERSION DAM ON THE SNAKE RIVER, LOOKING NORTHEAST. NOTE HEADGATE STRUCTURE ON NORTH BANK, SPILLWAY ON LEFT SIDE OF DAM, AND SPLASH LOGS ON DOWNSTREAM SIDE OF DAM. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

365

View of upstream face of the forebay dam of Grand ...  

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

View of upstream face of the forebay dam of Grand Coulee Dam, looking southwest. Note the trash racks at the entrance to the penstocks. - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

366

Problems of quality control in constructing earth dams  

Microsoft Academic Search

Conclusion 1.Current methods of conducting geotechnical control when constructing high earth dams do not have effective criteria for evaluating the technology and therefore they cannot provide real quality control of dam construction.2.A system of controlling the quality of constructing earth dams with the use of the technology safety factor analogous to the soil safety factor, realizing feedback of geotechnical control

A. G. Chernilov

1987-01-01

367

77. AVALON DAM Photographic copy of map dated 1895 ...  

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

77. AVALON DAM - Photographic copy of map dated 1895 (from Record Group 49, Division F, National Archives, Washington, D.C.) PLAT OF RESERVOIR NO. 2 BEING THE DISTRIBUTING RESERVOIR OF THE PECOS IRRIGATION AND IMPROVEMENT CO'S SOUTHERN CANAL SYSTEM INCLUDES PLAN AND CROSS SECTION OF DAM - Carlsbad Irrigation District, Avalon Dam, On Pecos River, 4 miles North of Carlsbad, Carlsbad, Eddy County, NM

368

Black-Tailed Prairie Dog  

USGS Multimedia Gallery

Black-tailed prairie dogs are quite susceptible to sylvatic plague, but a new plague vaccine put in their food shows significant promise in the laboratory. The prairie dogs transmit the disease to endangered black-footed ferrets, who eat the prairie dogs and are also quite susceptible to the disease...

2009-08-03

369

Estimating Tails of Probability Distributions  

Microsoft Academic Search

We study the asymptotic properties of estimators of the tail of a distribution based on the excesses over a threshold. A key idea is the use of Pickands' generalised Pareto distribution and its fitting, in most cases, by the method of maximum likelihood. The results cover all three limiting types of extreme value theory. We propose a new estimator for

Richard L. Smith

1987-01-01

370

Shape optimal design of materially nonlinear arch dams including dam-water-foundation rock interaction using an improved PSO algorithm  

Microsoft Academic Search

An efficient optimization procedure is proposed to find the optimal shape of arch dams including dam-water-foundation rock\\u000a interaction subject to earthquake. The arch dam is treated as a three-dimensional structure involving the material nonlinearity\\u000a effects. For this purpose, the nonlinear behavior of the dam concrete is idealized as an elasto-plastic material using the\\u000a Drucker-Prager model. In order to reduce the

Seyed Mohammad Seyedpoor; Javad Salajegheh; Eysa Salajegheh

371

Expression analysis of PpDAM5 and PpDAM6 during flower bud development in peach ( Prunus persica)  

Microsoft Academic Search

We previously reported transcript amounts of peach PpDAM5 and PpDAM6 (Prunus persica Dormancy-Associated MADS 5 and 6) were negatively correlated with endodormancy release of peach vegetative buds (Yamane et al., 2011). We here investigated PpDAM5 and PpDAM6 expressions in lateral flower buds of peach in relation to seasonal flower bud development by using peach cultivars differing in their chilling requirements,

Hisayo Yamane; Tomomi Ooka; Hiroaki Jotatsu; Ryuta Sasaki; Ryutaro Tao

2011-01-01

372

Federal Guidelines for Dam Safety: Earthquake Analyses and Design of Dams.  

National Technical Information Service (NTIS)

These guidelines provide the basic framework for the earthquake design and evaluation of dams. The general philosophy and principles for each part of the framework are described in sufficient detail to achieve a reasonable degree of uniform application am...

2005-01-01

373

Dams and Salmon: A Northwest Choice  

ERIC Educational Resources Information Center

This article describes an experiential exercise in which participants assume the roles of various stakeholder groups in the controversy surrounding possible dam removal to revive northwestern U. S. salmon populations. The role-play (a) increases environmental awareness in the context of the competing interests various stakeholders have in our…

Tucker, Michael; Tromley, Cheryl L.

2005-01-01

374

Aging Dams and Watersheds: Rehabilitation and Restoration  

NSDL National Science Digital Library

The US Department of Agriculture's Water Quality Information Center at the National Agricultural Library has placed a new database online. The bibliography on Aging Dams and Watersheds includes 33 citations (1984-1998) "intended primarily to provide awareness of recent investigations and discussions" of related topics; several citations are hyperlinked to the full-text articles.

375

Developments in Concrete Dam Construction in Turkey.  

National Technical Information Service (NTIS)

Economic exploitation of Turkey's water resources requires construction of about 600 dams. One-fifth of them are in operation, one-tenth under construction, one-eighth are at the stage of final design and more than half of them are only at the planning st...

U. Oezis M. Alsan

1990-01-01

376

Eye in the Sky: Floods and Dams  

NSDL National Science Digital Library

This site provides general information about floods and dams. There are sections on the science, the phenomenon, and effects of floods. One video clip shows the Mississippi River at flood and non-flood levels. Another clip shows actual footage of a flood wreaking havoc on a populated area.

377

Boca Dam Collapse Feature Investigation, Trip Report.  

National Technical Information Service (NTIS)

The purpose of the report is: 1. To conduct investigations of the collapse feature identified in MP-230's April 28, 2008 Earthquake Inspection Trip Report for Boca and Stampede Dams, to the left of the spillway, downhill from the toe of the dike. 2. To de...

G. Egan M. McCulla

2008-01-01

378

Hyraulic Model Studies Yellowtail Afterbay Dam Sluiceway.  

National Technical Information Service (NTIS)

The purpose of this study was to determine the best location for installing a flow deflector to reduce gas supersaturation below Yellowtail Afterbay Dam. Supersaturation occurs when entrained air in the hydraulic jump is carried to depth in the stilling b...

M. F. Young

1982-01-01

379

National Program for Inspection of Non-Federal Dams. Richville Dam (VT 00074) Richelieu River Basin, Shoreham, Vermont.  

National Technical Information Service (NTIS)

The dam is a concrete gravity dam with an overall length of 116 ft. and a height of 15 ft. It is small in size with a low hazard potential. The dam is in good condition. There are a few items which need maintenance and repair. (Author)

1978-01-01

380

National Dam Safety Program. Kooglers Dam (Inventory Number VA 16305), James River Basin, Rockbridge County, Virginia. Phase I Inspection Report.  

National Technical Information Service (NTIS)

The Dam is an earthfill structure about 1000 feet long and 23.3 feet high with a gravel roadway traversing the entire dam. The dam is classified as small on the basis of size, and given a hazard classification of significant on the basis of downstream are...

B. O. Taran

1981-01-01

381

National Dam Safety Program. Turner Dam (Inventory Number VA 16308), James River Basin, Rockbridge County, Virginia. Phase I Inspection Report.  

National Technical Information Service (NTIS)

The dam is an earthfill structure about 800 feet long and 45.2 feet high. The dam is classified as an intermediate size dam with a significant hazard classification. The designed principal spillway is a 10-inch steel drop-inlet stand pipe located in the r...

B. O. Taran

1981-01-01

382

National Dam Safety Program. Seneca Falls Dam, Seneca River Basin, Seneca River, Seneca County, New York. Phase I Inspection Report.  

National Technical Information Service (NTIS)

This report provides information and analysis on the physical condition of the dam as of the report date. Information and analysis are based on visual inspection of the dam by the performing organization. Seneca Falls Dam was found to be unsafe-non emerge...

J. J. Williams

1978-01-01

383

Uranium-Mill-Tailings Conditioning Technology.  

National Technical Information Service (NTIS)

Conditioning of uranium mill tailings involves the physico-chemical alteration of tailings to remove or immobilize mobile radionuclides and toxic trace elements before disposal in a repository. The principal immobilization approach under investigation is ...

D. R. Dreesen E. J. Cokal P. D. O'Brien E. F. Thode L. E. Wangen

1982-01-01

384

Uranium Mill Tailings Remedial Action Technology.  

National Technical Information Service (NTIS)

The uranium milling process involves the hydrometallurgical extraction of uranium from ores and the resultant generation of large quantities of waste referred to as tailings. Uranium mill tailings have been identified as requiring remediation because they...

J. N. Hartley G. W. Gee

1984-01-01

385

Turbo decoding with tail-biting trellises  

Microsoft Academic Search

Tail-biting codes are considered as component codes for parallel concatenated block codes. Based on the two-dimensional weight distribution of tail-biting codes, we calculate the minimum distance of the parallel concatenated code and give guidelines on how to choose good tail-biting component codes. We show how to encode tail-biting codes using systematic feedback encoders, which is an important design criterion. The

C. Weiss; Christian Bettstetter; Sven Riedel

1998-01-01

386

Failure Assessment  

NASA Technical Reports Server (NTRS)

Three questions to which software developers want accurate, precise answers are "How can the software system fail?", "mat bad things will happen if the software fails?t', and "How many failures will the software experience?". Numerous techniques have been devised to answer these questions; three of the best known are: 1) Software Fault Tree Analysis (SFTA) 2) Software Failure Modes, Effects, and Criticality Analysis (SFMECA 3) Software Fault/Failure Modeling. SFTA and SFMECA have been successfully used to analyze the flight software for a number of robotic planetary exploration missions, including Galileo, Cassini, and Deep Space 1. Given the increasing interest in reusing software components from mission to mission, one of us has developed techniques for reusing the corresponding portions of the SFTA and SFMECA, reducing the effort required to conduct these analyses. SFTA has also been shown to be effective in analyzing the security aspects of software systems; intrusion mechanisms and effects can easily be modeled using these techniques. The Bi- Directional Safety Analysis (BDSA) method combines a forward search (similar to SFMECA) from potential failure modes to their effects, with a backward search (similar to SFTA) from feasible hazards to the contributing causes of each hazard. BDSA offers an efficient way to identify latent failures. Recent work has extended BDSA to product-line applications such as flight-instrumentation displays and developed tool support for the reuse of the failure-analysis artifacts within a product line. BDSA has also been streamlined to support those projects having tight cost and/or schedule constraints for their failure analysis efforts. We discuss lessons learned from practice, describe available tools, and identi@ some future directions for the topic. A substantial amount of research has been devoted to estimating the number of failures that a software system will experience during test and operations, as well as the number of faults that have been inserted into that system during its development. One of us has found that the amount of structural change to a system during its development is strongly related to the number of faults inserted into it. Using techniques requiring no additional effort on the part of the development organization, the required measurements of structural evolution can be easily obtained from a development effort's configuration management system and readily transformed into an estimate of fault content. So far, structure-fault relationships have been identified for source code; current work seeks to examine artifacts available earlier in the lifecycle to determine if similar relationships between structure and fault content can be found. In particular, relationships between requirements change requests and the number of faults inserted into the implemented system would provide a significant improvement in our ability to control software quality during the early development phases.

Lutz, Robyn; Nikora, Allen

2005-01-01

387

School Failure  

Microsoft Academic Search

School failure is an important worldwide issue, leading to underemployment (unemployment or job dissatisfaction) and a lower\\u000a quality of life. The overall dropout rate in the United States is 10–25%, depending on how it is reckoned. But it is common\\u000a for the most struggling high schools to lose 25–50% of their students between 9th and 12th grade, and on any

Peter W. Dowrick; Natalie Crespo

388

Colonization of mine tailings by marine invertebrates  

Microsoft Academic Search

An experiment was conducted to determine if a tailings substrate would inhibit recolonization of benthic macrofauna upon closure of a submarine tailings disposal (STD) operation. Trays of defaunated marine sediment, serving as a reference, and trays of tailings from a proposed gold mine were placed at 21 m depth on the ocean floor to allow colonization via settlement from the

E. R Kline; M. S Stekoll

2001-01-01

389

Seismic risk ranking for large dams in South Africa  

NASA Astrophysics Data System (ADS)

Earthquake motion is one of the extreme loads acting on large dams. Dam owners and regulators must therefore ensure that dams are safely operated and present minimal risk to the public in case of extreme loads such as floods and earthquakes. Owners of many dams or officials in charge of dam safety programs may consider comparative assessment of the seismic risk associated with their dams and establish priorities for detailed evaluation. South Africa has in excess of 100 large state-owned dams and the characteristics of these dams have been used to perform a basic seismic hazard assessment and rank the vulnerability of these dams from the lowest to highest. One of the most decisive factors that contributes to the risk of a dam is the wall type; with gravity and earthfill dams being the most vulnerable to earthquake motion. Another aspect that needs further investigation is the downstream hazard potential which, if known to a better degree of accuracy, can provide more reasonable estimates of the risk factors.

Singh, Mayshree; Kijko, Andrzej; van den Berg, Leo

2011-02-01

390

Tail Dependence for Heavy-Tailed Scale Mixtures of Multivariate Distributions  

Microsoft Academic Search

The tail dependence of multivariate distributions is frequently studied via the tool of copulas. This paper develops a general method, which is based on multivariate regular variation, to evaluate the tail dependence of heavy-tailed scale mixtures of multivariate distributions, whose copulas are not explicitly accessible. Tractable formulas for tail dependence parameters are derived, and a sucient condition under which the

Haijun Li; Yannan Grace Sun

391

IMPACTS OF WHITE-TAILED DEER ON FOREST REGENERATION IN NORTHWEST ERN PENNSYLVANIA  

Microsoft Academic Search

Browsing by white-tailed deer (Odocoileus virginianus) is a major cause of regeneration failure in Allegheny hardwood forests of northwestern Pennsylvania. I examined the impact of deer at 5 different densities (0, 10, 20, 40, and 80 deer\\/259 ha) on tree seedlings, woody shrubs, and herbaceous plants in large enclosures over 5 years. I examined 3 silvicultural treatments (clearcut, thinning, and

NANCY G. TILGHMAN

392

The Uranium Mill Tailings Radiation Control Act of 1978 and NRC's Agreement State Program  

Microsoft Academic Search

The Uranium Mill Tailings Radiation Control Act of 1978 sought to remedy an earlier failure to regulate this environmental hazard and to provide funding for cleanup and management. The Act also links standards set in the Agreement State program of 1959 to minimum federal standards of the Nuclear Regulatory Commission. Analysis of the Act and the Agreement States program shows

ELISA J. GRAMMER

1981-01-01

393

Uranium mill tailings quarterly report, January-March 1982  

Microsoft Academic Search

Progress is reported on: radon barrier systems for uranium mill tailings; liner evaluation for uranium mill tailings; revegetation\\/rock cover for stabilization of inactive U-tailings sites; and application of long-term chemical biobarriers for uranium tailings.

Latkovich

1982-01-01

394

Extracting aluminum from dross tailings  

NASA Astrophysics Data System (ADS)

Aluminum dross tailings, an industrial waste, from the Egyptian Aluminium Company (Egyptalum) was used to produce two types of alums: aluminum-sulfate alum [itAl2(SO4)3.12H2O] and ammonium-aluminum alum [ (NH 4)2SO4AL2(SO4)3.24H2O]. This was carried out in two processes. The first process is leaching the impurities using diluted H2SO4 with different solid/liquid ratios at different temperatures to dissolve the impurities present in the starting material in the form of solute sulfates. The second process is the extraction of aluminum (as aluminum sulfate) from the purifi ed aluminum dross tailings thus produced. The effects of temperature, time of reaction, and acid concentration on leaching and extraction processes were studied. The product alums were analyzed using x-ray diffraction and thermal analysis techniques.

Amer, A. M.

2002-11-01

395

Tadpole tail regeneration in Xenopus.  

PubMed

Some organisms have a remarkable ability to heal wounds without scars and to regenerate complex tissues following injury. By gaining a more complete understanding of the biological mechanisms that promote scar-free healing and tissue regeneration, it is hoped that novel treatments that can enhance the healing and regenerative capacity of human patients can be found. In the present article, we briefly examine the genetic, molecular and cellular mechanisms underlying the regeneration of the Xenopus tadpole tail. PMID:24849228

Chen, Yaoyao; Love, Nick R; Amaya, Enrique

2014-06-01

396

Chapter 17 Placing soil covers on soft mine tailings  

Microsoft Academic Search

Mine tailings are typically silt-sized materials derived from mineral processing, which are conventionally pumped as an aqueous slurry, thickened tailings or tailings paste to a tailings storage facility, usually a surface impoundment. On discharge, an aqueous tailings slurry forms a delta, on which the tailings particles undergo hydraulic sorting, sedimentation and self-weight consolidation, and desiccation on exposure to evaporation. Their

David John Williams

2005-01-01

397

Dam removal increases American eel abundance in distant headwater streams  

USGS Publications Warehouse

American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwater streams increased significantly after the removal of Embrey Dam. Observed eel abundances after dam removal exceeded predictions derived from autoregressive models parameterized with data prior to dam removal. Mann–Kendall analyses also revealed consistent increases in eel abundances from 2004 to 2010 but inconsistent temporal trends before dam removal. Increasing eel numbers could not be attributed to changes in local physical habitat (i.e., mean stream depth or substrate size) or regional population dynamics (i.e., abundances in Maryland streams or Virginia estuaries). Dam removal was associated with decreasing minimum eel lengths in headwater streams, suggesting that the dam previously impeded migration of many small-bodied individuals (<300 mm TL). We hypothesize that restoring connectivity to headwater streams could increase eel population growth rates by increasing female eel numbers and fecundity. This study demonstrated that dams may influence eel abundances in headwater streams up to 150 river kilometers distant, and that dam removal may provide benefits for eel management and conservation at the landscape scale.

Hitt, Nathaniel P.; Eyler, Sheila; Wofford, John E. B.

2012-01-01

398

Heart failure.  

PubMed

Despite major improvements in the treatment of virtually all cardiac disorders, heart failure (HF) is an exception, in that its prevalence is rising, and only small prolongations in survival are occurring. An increasing fraction, especially older women with diabetes, obesity, and atrial fibrillation exhibit HF with preserved systolic function. Several pathogenetic mechanisms appear to be operative in HF. These include increased hemodynamic overload, ischemia-related dysfunction, ventricular remodeling, excessive neurohumoral stimulation, abnormal myocyte calcium cycling, excessive or inadequate proliferation of the extracellular matrix, accelerated apoptosis, and genetic mutations. Biomarkers released as a consequence of myocardial stretch, imbalance between formation and breakdown of extracellular matrix, inflammation, and renal failure are useful in the identification of the pathogenetic mechanism and, when used in combination, may become helpful in estimating prognosis and selecting appropriate therapy. Promising new therapies that are now undergoing intensive investigation include an angiotensin receptor neprilysin inhibitor, a naturally-occurring vasodilator peptide, a myofilament sensitizer and several drugs that enhance Ca++ uptake by the sarcoplasmic reticulum. Cell therapy, using autologous bone marrow and cardiac progenitor cells, appears to be promising, as does gene therapy. Chronic left ventricular assistance with continuous flow pumps is being applied more frequently and successfully as destination therapy, as a bridge to transplantation, and even as a bridge to recovery and explantation. While many of these therapies will improve the care of patients with HF, significant reductions in prevalence will require vigorous, multifaceted, preventive approaches. PMID:24621794

Braunwald, Eugene

2013-02-01

399

The hydrogeology of a tailings impoundment formed by central discharge of thickened tailings: implications for tailings management  

NASA Astrophysics Data System (ADS)

The Kidd Creek Cu-Zn sulfide mine is located near Timmins, Ontario. Mill tailings are thickened and deposited as a slurry in a circular impoundment with an area of approximately 1200 ha. Deposition of tailings as a thickened slurry from a central discharge ramp results in a conical-shaped tailings deposit with low perimeter dykes, a uniform grain-size distribution, uniform and low hydraulic conductivity, and a tension-saturated zone above the water table up to 5 to 6 m thick. These characteristics provide benefits over conventionally disposed tailings with respect to tailings management. The thick tension-saturated zone within the tailings limits the thickness of unsaturated tailings that are susceptible to rapid sulfide oxidation. The conical shape of the deposit results in the formation of a recharge area near the centre of the impoundment and discharge in the peripheral areas. In contrast, the elevated nature of many conventional, unthickened tailings impoundments results in recharge over most of the surface of the impoundment, with discharge occurring outside the impoundment through large containment dykes. Three-dimensional pore water flow modelling suggests that approximately 90% of the total discharge from the thickened tailings occurs within the tailings impoundment. When discharge is confined within the impoundment, there is improved control over low-quality effluent, and an opportunity to design passive control measures to reduce treatment costs and minimize environmental impacts.

Al, Tom A.; Blowes, David W.

1999-06-01

400

The Effects of Solute Breakthrough Curve Tail Truncation on Residence Time Estimates and Mass Recovery  

NASA Astrophysics Data System (ADS)

Solute transport and hydrologic retention strongly affect biogeochemical processes that are critical to stream ecosystems. Tracer injections are used to characterize solute transport and storage in stream reaches, but the range of processes accurately resolved using this approach is not clear. The solute residence time distribution (RTD) depends on both in-stream mixing and exchange with the hyporheic zone. For shorter residence times, in-stream breakthrough curves (BTCs) can be modeled well with the classical advection-dispersion equation, whereas longer RTDs produce highly skewed in-stream BTCs for which traditional solute models are inappropriate. Observed BTCs have most commonly been modeled with in-stream advection-dispersion plus an exponential RTD, but process-based models suggest that hyporheic retention extends to much longer times and a power-law RTD is more appropriate. We synthesized results from a variety of tracer-injection studies to investigate how experimental design and tracer sensitivity influence the interpretation of tailing behavior and RTDs. We found that BTC tails are often not well observed in stream tracer experiments. The two main reasons for this are: 1) experimental truncation, which occurs when sampling ends before all tracer mass reaches the sampling location, and 2) sensitivity truncation, when tracer concentrations in the tail are too low to be detected reliably above background levels. Continuous Time Random Walk (CTRW) theory was used to determine the effects of tail truncation on tracer mass recovery and tailing behavior. Tail truncation due to both experimental and sensitivity truncation decreased mass recovery and obscured assessment of BTC tailing. Failure to consider tail truncation leads to underestimation of the retention of solutes in the streambed and subsurface (i.e., transient storage). Based on these findings, we propose criteria for stream tracer experiments to minimize tail truncation and improve inverse modeling of solute transport.

Drummond, J. D.; Covino, T. P.; Aubeneau, A. F.; Patil, S.; Leong, D. N.; Ran, L.; Packman, A. I.; Schumer, R.

2010-12-01

401

Placental transfer of melamine and its effects on rat dams and fetuses.  

PubMed

In 2008, an epidemic of cases of renal failure among Chinese infants, due to melamine contamination of milk, raised international concern. Thus, numerous studies on the metabolism of melamine were broadly undertaken. However, little is known about placental transfer of melamine. In this study, the possibility of placental transfer of melamine and its effects on fetuses and pregnant dams were determined. Melamine was respectively administered at 0, 40 and 400mg/kg body weight by daily gavage from gestation day (GD) 13 to GD 20 to control (C), low melamine (LM) and high melamine (HM) groups of pregnant female F344 rats. Rats were sacrificed 30min after the last gavage. Melamine was not detected in any of the control and placental samples, or in amniotic fluid from the LM group. Plasma and fetal melamine concentrations in the HM group were significantly higher than in the LM group (P<0.01). Liver enzyme determination revealed no differences among the three groups. However, plasma creatinine, plasma uric acid and blood urea nitrogen concentrations in dams were significantly increased by melamine (P<0.05). These results show that ingested melamine affects renal function in dams and dose-dependently passes the placental barrier to reach the fetus. PMID:20362637

Jingbin, Wang; Ndong, Moussa; Kai, Hisahiro; Matsuno, Koji; Kayama, Fujio

2010-07-01

402

Distribution and prevention of dammed lakes triggered by Wenchuan earthquake  

NASA Astrophysics Data System (ADS)

Wenchuan earthquake induced large-scale of collapses and landslides which blocked river channels and brought about quantities of dammed lakes. The number and the scale of dammed lakes are extremely rare in the world. Besides the backwater of the dammed lakes can flood the road traffic, villages and farmland on the upstream, it can severely threaten the safety of the people's lives and properties on the downstream. Once the dammed lakes burst out, they can cause severe flood disaster. Therefore, it is urgent to monitor the dammed lakes, study their distribution and analyze their development by means of remote sensing (RS) and geography information system (GIS) after the earthquake. In this paper, 145 high-resolution images were processed and 31 severely-afflicted counties were studied through RS monitoring and field investigation. By the time of May 28,2008, 257 dammed lakes existing more than 14 days were identified and there were 34 dammed lakes with capacity of more than 100 000m3. Based on these conditions, the distribution and development of dammed lakes were discussed and the findings showed that: (a) The dammed lakes induced by Wenchuan earthquake mainly scatter in Beichuan, Wenchuan, Shifang, Mianzhu and Anxian counties, and there exist 154 dammed lakes in these regions, which is 59.92 percent of the total. (b) 95.3 percent of the dammed lakes are within 10km of three major fault zones of Longmen Mountains and the relationship between the number of dammed lakes and their distance to fault zone accords with the law of logarithmic decrement. (c) Most of dammed lakes are distributed in the upper reaches of Minjiang River, Tuojiang River, Jianjiang River and Fujiang River, etc. in rosary. (d) The distribution of dammed lakes in the study areas is dominated by seismic intensity, lithology, slope and altitude. In the next 5-10 years, collapses, landslides and debris flows in the study area will occur frequently and severely and they are likely to block river channels and form dammed lakes. As rainy season comes, the risk of dammed lakes forming and bursting is increasing. So it is necessary to reinforce the real-time monitoring of dammed lakes, make risk assessment and formulate the emergency countermeasures.

Han, Yongshun; Liu, Hongjiang; Zhu, Boqin; Han, Jun; Yang, Yingchang; Zhang, Yu

2009-09-01

403

Dams and Rivers: A Primer on the Downstream Effects of Dams  

USGS Publications Warehouse

The U.S. Geological Survey is charged with monitoring the water and mineral resources of the United States. Beginning in 1889, the Survey established a network of water gaging stations across most of the country's rivers; some also measured sediment content of the water. Consequently, we now have valuable long-term data with which to track water supply, sediment transport, and the occurrence of floods. Many variables affect the flow of water from mountain brook to river delta. Some are short-term perturbations like summer thunderstorms. Others occur over a longer period of time, like the El Ninos that might be separated by a decade or more. We think of these variables as natural occurrences, but humans have exerted some of the most important changes -- water withdrawals for agriculture, inter-basin transfers, and especially the construction of an extensive system of dams. Dams have altered the flow of many of the Nation's rivers to meet societal needs. We expect floods to be contained. Irrigation is possible where deserts once existed. And water is released downstream not according to natural cycles but as dictated by a region's hour-by-hour needs for water or electricity. As a result, river channels below dams have changed dramatically. Depending on annual flow, flood peaks, and a river's sediment load, we might see changes such as sand building up in one channel, vegetation crowding into another, and extensive bank erosion in another. This Circular explores the emerging scientific arena of change in rivers below dams. This science tries first to understand and then anticipate changes to river beds and banks, and to riparian habitats and animal communities. To some degree, these downstream changes can be influenced by specific strategies of dam management. Scientists and resource managers have a duty to assemble this information and present it without bias to the rest of society. Society can then more intelligently choose a balance between the benefits and adverse downstream effects of dams.

Collier, Michael; Webb, Robert H.; Schmidt, John C.

1996-01-01

404

Oblique view, looking west, of top side of diversion dam, ...  

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

Oblique view, looking west, of top side of diversion dam, also showing eastern profiles of piers and gatehouses. Roller gate (raised position) on right. Note detail of extension shield that, when lowered to a secure position against the dam sill, creates a virtually impervious seal - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

405

Characterization of landslide dams in the San Juan province (Argentina)  

NASA Astrophysics Data System (ADS)

River blockages caused by landslide deposition are common phenomena in active mountain chains, influencing erosion-sedimentation patterns and acting as primary and secondary hazards. Regional scale analyses regarding their spatial distribution and morphometry allow establishing boundary conditions for their occurrence and stability, and determine differences among regions with different landscape and climatic conditions. Owing to the combination of endogenous and exogenous factors, landslide dams are frequent phenomena in the Andes. In the Argentinean NW and the Patagonian Andes, previous studies showed that stability of landslide dams determined by morphometric parameters generally matched satisfactorily with dam behavior, with some exceptions in which climatic component played an important role in dam longevity. Aiming to expand the knowledge of landslide dams in the Argentinean Andes, in this work we analyzed the stability of rock avalanche dams in the Pampeam flat slab subduction zone. In the study area, mountain dynamics creates suitable conditions for the occurrence of 34 rock avalanches with volumes up to 0.3 km3. They developed in deeply carved valleys (Cordillera) and Inter-thrust valleys (Precordillera). 22 impoundments of rivers resulted from channelized rock avalanches with long runouts (4-10 km) that blocked tributaries rivers, but most of them by rock avalanches that filled the valley bottom, with run up in the opposite slope and limited movement parallel to the valley axis. Most of the dams breached in unknown times, except for the last event that occurred on November 12th 2005. The quantification of morphometric parameters and contributing areas indicates the existence of dams with dimensionless blockage index above 2.75 (stable domain) and below 3.08 (instable domain). The Los Erizos dam in our study area and the Barrancas dam in the Patagonian Andes show that besides morphometric parameters, climatic conditions are decisive. Stable landslide dams lasting for millennia can collapse suddenly due to anomalous weather conditions, and unstable dams can have a higher longevity depending on the season controlling the inflow into the lake.

Penna, Ivanna; Longchamp, Celine; Derron, Marc-Henri; Jaboyedoff, Michel

2013-04-01

406

Experimental investigation of dynamic pressure loads during dam break  

NASA Astrophysics Data System (ADS)

The objectives of this work are to revisit the experimental measurements on dam break flow over a dry horizontal bed and to provide a detailed insight into the dynamics of the dam break wave impacting a vertical wall downstream the dam, with emphasis on the pressure loads. The measured data are statistically analyzed and critically discussed. As a result, an extensive set of data for validation of computational tools is provided.

Lobovský, L.; Botia-Vera, E.; Castellana, F.; Mas-Soler, J.; Souto-Iglesias, A.

2014-07-01

407

Dynamic analysis of an inflatable dam subjected to a flood  

Microsoft Academic Search

A dynamic simulation of the response of an inflatable dam subjected to a flood is carried out to determine the survivability\\u000a envelope of the dam where it can operate without rupture, or overflow. The free-surface flow problem is solved in two dimensions\\u000a using a fully nonlinear mixed Eulerian-Lagrangian formulation. The dam is modeled as an elastic shell inflated with air

K. Lowery; S. Liapis

1999-01-01

408

1. CONTEXTUAL VIEW OF THE NORTH CHANNEL DAM FROM PUBLICLY ...  

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

1. CONTEXTUAL VIEW OF THE NORTH CHANNEL DAM FROM PUBLICLY RESTRICTED PROPERTY OF THE RECENTLY CLOSED LOUISIANA PACIFIC LUMBER MILL. THE NORTH CHANNEL DAM'S HOLDING RESERVOIR AND TAINTER GATES ARE IN THE FOREGROUND, AND THE ROLLING SECTOR GATE IS IN THE BACKGROUND, LOOKING EAST. - Washington Water Power Company Post Falls Power Plant, North Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

409

The Tous Dam Disaster of 1982: Risk communication and the origins of integrated flood risk management in Spain  

NASA Astrophysics Data System (ADS)

The failure of Tous dam on the Júcar River near Valencia in 1982 was one of the most important socio-natural disasters in 20th century Spain. The death toll of 25 would have been much greater had not a local dam manager anticipated the failure and alerted mayors of a failure, before it actually occurred. The Tous Dam failure occurred a week before the first democratic elections in Spain after the Franco dictatorship, it received extensive coverage in the media. As a result, this disaster triggered a paradigm change in the way disaster risks were perceived and managed at multiple levels of government in Spain. Many factors, often of a qualitative and organisational nature, affect (vertical and horizontal) communication in disaster risk reduction learning and planning at the community level. Through interviews with key actors and stakeholders, content analysis of scientific literature, review of historical and media accounts, and analysis of legislation and regulation, we documented changes that resulted from the Tous Dam failure: (1) A process of institutional development, which led to the growth, and increase in complexity of the organisations involved both in vertical and horizontal communication of disaster risk reduction. (2) Actions taken and experiences gained in dealing with disaster risk reduction in the Tous area were used as a benchmark to develop new strategies, as well as new mechanisms for communication and planning in other territories and other risk domains in Spain.We identify three main stages from 1980s to present in the evolution of disaster risk reduction planning in the area, which show a progressive shift towards a more integrated and preventative approach: (1) After the collapse of the Tous Dam, disaster risk reduction strategies in Spain focused on improving preparedness in order to reduce short-term risks. (2) Disaster management in the 1990s was strongly influenced by international initiatives (e.g. the UN International Decade for Natural Disaster Reduction), which emphasized the contextualization of risk and the importance in long-term disaster risk reduction measures such as land use planning. (3) The European Water Framework Directive (2000) and, more recently, the Flood Directive (2007) are exerting a strong influence on the development of a new Spanish flood policy that focuses on preventive measures and integrates, for the first time, ecological concerns and climate change adaptation in flood management strategies.

Serra-Llobet, A.; Tàbara, J.; Sauri, D.

2012-12-01

410

5. EASTSIDE RESERVOIR, LOOKING WEST. WEST DAM UNDER CONSTRUCTION, QUARRIES ...  

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

5. EASTSIDE RESERVOIR, LOOKING WEST. WEST DAM UNDER CONSTRUCTION, QUARRIES TO LEFT MIDDLE GROUND OF PICTURE. - Eastside Reservoir, Diamond & Domenigoni Valleys, southwest of Hemet, Hemet, Riverside County, CA

411

2. FORMER INTAKE DAM NO. 2 AT 560" CONSTRUCTED OF ...  

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

2. FORMER INTAKE DAM NO. 2 AT 560" CONSTRUCTED OF RUBBLE MASONRY IN 1937-1938. VIEW LOOKING DOWN LINE FORMER INTAKE GRILLE WAS TO LEFT SIDE OF DAM (TWO 8" IRON PIPES FROM NEW INTAKE NOW ENTER OLD INTAKE OPENING), BOX FLUME EXITS AT RIGHT AND CARRIES WATER TO AERATOR. NOTE THE SMALL SLUICEWAY OPENING AT CENTER ALONG WATERLINE. THIS DAM WAS SUPERCEDED BY THE NEW INTAKE DAM TO REACH THE MORE RELIABLE WATER SOURCE OF THE MAIN STREAM. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

412

Thermal stabilization of uranium mill tailings  

Microsoft Academic Search

The treatment of uranium mill tailings by high-temperature sintering (>1050°C) has been investigated as a means of controlling the release of ²²²Rn and leachable contaminants. Thermal stabilization in laboratory trials at 1200°C reduced the radon emanation of various tailings by factors ranging from 37 to 1400 depending on the mineralogy of the tailings. The leachability of most contaminants (e.g., Al,

David R. Dreesen; Edward J. Cokal; Lawrence E. Wangen; Joel M. Williams; Edward F. Thode

1984-01-01

413

Active tails enhance arboreal acrobatics in geckos.  

PubMed

Geckos are nature's elite climbers. Their remarkable climbing feats have been attributed to specialized feet with hairy toes that uncurl and peel in milliseconds. Here, we report that the secret to the gecko's arboreal acrobatics includes an active tail. We examine the tail's role during rapid climbing, aerial descent, and gliding. We show that a gecko's tail functions as an emergency fifth leg to prevent falling during rapid climbing. A response initiated by slipping causes the tail tip to push against the vertical surface, thereby preventing pitch-back of the head and upper body. When pitch-back cannot be prevented, geckos avoid falling by placing their tail in a posture similar to a bicycle's kickstand. Should a gecko fall with its back to the ground, a swing of its tail induces the most rapid, zero-angular momentum air-righting response yet measured. Once righted to a sprawled gliding posture, circular tail movements control yaw and pitch as the gecko descends. Our results suggest that large, active tails can function as effective control appendages. These results have provided biological inspiration for the design of an active tail on a climbing robot, and we anticipate their use in small, unmanned gliding vehicles and multisegment spacecraft. PMID:18347344

Jusufi, Ardian; Goldman, Daniel I; Revzen, Shai; Full, Robert J

2008-03-18

414

The human tail and spinal dysraphism.  

PubMed

Recent publications have endeavoured to differentiate between the true, or vestigial tail, and the pseudotail by clinical and pathological examination, and have indicated the benign nature of the true tail. The true tail arises from the most distal remnant of the embryonic tail, contains adipose, connective, muscle, and nerve tissue, and is covered by skin. Pseudotails represent a variety of lesions having in common a lumbosacral protrusion and a superficial resemblance to vestigial tails. A review of the case reports indicates spina bifida to be the most frequent coexisting anomaly with both. A review of occult spinal dysraphism shows it to be associated with cutaneous signs in more than 50% of instances. Three cases of spinal dysraphism with tail-like cutaneous structures are described and their radiological, operative, and pathological findings presented. The classification of each of the appendages into true tail or pseudotail remains obscure. Although the finding of these three tails was the subject of much curiosity, surgical treatment was clearly designed to adequately deal with the associated dysraphic state. The presence of a tail-like appendage in the lumbosacral region should alert the clinician to the possibility of underlying spinal dysraphism. Preoperative assessment must include a complete neurological history and examination as well as computed tomographic or magnetic resonance imaging. PMID:1779337

Belzberg, A J; Myles, S T; Trevenen, C L

1991-10-01

415

The storage and release of water from a large glacier-dammed lake; Russell Lake near Yakutat, Alaska, 1986  

USGS Publications Warehouse

In May 1986, the entrance to Russell Fiord, Alaska, was blocked by the advancing Hubbard Glacier, forming a 34-mile long ice-dammed lake. Runoff to the lake, mainly runoff from melting snow and glacier ice, filled the lake to an elevation of 83 feet above sea level by October 8, when the ice dam failed. The lake level rose at an average rate of 0.6 ft/day, and average daily inflow to the lake was calculated to be 16,500 cu ft/sec. After failure of the ice dam, the water level fell to the former high tide level of Russell Fiord within 24 hours. Average discharge through the breach in the ice dam during a 4-hr period of maximum water level decline is estimated to have been 3.8 million cu ft/sec. The formation and breakout of the lake is expected to be repeated as the Hubbard Glacier continues to advance, though the timing of the phenomenon cannot be predicted with certainty. (USGS)

Seitz, H. R.; Thomas, D. S.; Tomlinson, Bud

1986-01-01

416

National Program for Inspection of Non-Federal Dams. Big Island Pond Dam (NH 470), Merrimack River Basin, Derry, New Hampshire. Phase I Inspection Report.  

National Technical Information Service (NTIS)

The dam is a stone masonry dam with earth abutments. The dam is 80 ft. long with a maximum height of 10 ft. The dam has an irregular configuration, having experienced various modifications and repairs. It is considered to be in the significant hazard cate...

1978-01-01

417

Dam Design can Impede Adaptive Management of Environmental Flows: A Case Study from the Opuha Dam, New Zealand  

NASA Astrophysics Data System (ADS)

The Opuha Dam was designed for water storage, hydropower, and to augment summer low flows. Following its commissioning in 1999, algal blooms (dominated first by Phormidium and later Didymosphenia geminata) downstream of the dam were attributed to the reduced frequency and magnitude of high-flow events. In this study, we used a 20-year monitoring dataset to quantify changes associated with the dam. We also studied the effectiveness of flushing flows to remove periphyton from the river bed. Following the completion of the dam, daily maximum flows downstream have exceeded 100 m3 s-1 only three times; two of these floods exceeded the pre-dam mean annual flood of 203 m3 s-1 (compared to 19 times >100 m3 s-1 and 6 times >203 m3 s-1 in the 8 years of record before the dam). Other changes downstream included increases in water temperature, bed armoring, frequency of algal blooms, and changes to the aquatic invertebrate community. Seven experimental flushing flows resulted in limited periphyton reductions. Flood wave attenuation, bed armoring, and a shortage of surface sand and gravel, likely limited the effectiveness of these moderate floods. Floods similar to pre-dam levels may be effective for control of periphyton downstream; however, flushing flows of that magnitude are not possible with the existing dam infrastructure. These results highlight the need for dams to be planned and built with the capacity to provide the natural range of flows for adaptive management, particularly high flows.

Lessard, JoAnna; Murray Hicks, D.; Snelder, Ton H.; Arscott, David B.; Larned, Scott T.; Booker, Doug; Suren, Alastair M.

2013-02-01

418

Dam design can impede adaptive management of environmental flows: a case study from the Opuha Dam, New Zealand.  

PubMed

The Opuha Dam was designed for water storage, hydropower, and to augment summer low flows. Following its commissioning in 1999, algal blooms (dominated first by Phormidium and later Didymosphenia geminata) downstream of the dam were attributed to the reduced frequency and magnitude of high-flow events. In this study, we used a 20-year monitoring dataset to quantify changes associated with the dam. We also studied the effectiveness of flushing flows to remove periphyton from the river bed. Following the completion of the dam, daily maximum flows downstream have exceeded 100 m(3) s(-1) only three times; two of these floods exceeded the pre-dam mean annual flood of 203 m(3) s(-1) (compared to 19 times >100 m(3) s(-1) and 6 times >203 m(3) s(-1) in the 8 years of record before the dam). Other changes downstream included increases in water temperature, bed armoring, frequency of algal blooms, and changes to the aquatic invertebrate community. Seven experimental flushing flows resulted in limited periphyton reductions. Flood wave attenuation, bed armoring, and a shortage of surface sand and gravel, likely limited the effectiveness of these moderate floods. Floods similar to pre-dam levels may be effective for control of periphyton downstream; however, flushing flows of that magnitude are not possible with the existing dam infrastructure. These results highlight the need for dams to be planned and built with the capacity to provide the natural range of flows for adaptive management, particularly high flows. PMID:23124551

Lessard, JoAnna; Hicks, D Murray; Snelder, Ton H; Arscott, David B; Larned, Scott T; Booker, Doug; Suren, Alastair M

2013-02-01

419

33 CFR 222.6 - National Program for Inspection of Non-Federal Dams.  

Code of Federal Regulations, 2013 CFR

...generally applicable to rockfill dams and to earth dams on foundations containing weak...of the dam and within the foundation; earth and silt loads; ice pressure...and abutments (concrete, rock, grass, earth) and length of limited service and...

2013-07-01

420

75 FR 439 - Glen Canyon Dam Adaptive Management Work Group (AMWG)  

Federal Register 2010, 2011, 2012, 2013

...INTERIOR Bureau of Reclamation Glen Canyon Dam Adaptive Management Work Group (AMWG...SUMMARY: The Glen Canyon Dam Adaptive Management Program (AMP) was...Decision on the Operation of Glen Canyon Dam Final Environmental Impact Statement...

2010-01-05

421

78 FR 54482 - Charter Renewal, Glen Canyon Dam Adaptive Management Work Group  

Federal Register 2010, 2011, 2012, 2013

...4073000] Charter Renewal, Glen Canyon Dam Adaptive Management Work Group AGENCY...renewing the charter for the Glen Canyon Dam Adaptive Management Work Group. The purpose...concerning the operation of Glen Canyon Dam and the exercise of other authorities...

2013-09-04

422

78 FR 35630 - Martin Dam Hydroelectric Project; Notice of Availability of the Draft Environmental Impact...  

Federal Register 2010, 2011, 2012, 2013

...Project No. 349-173] Martin Dam Hydroelectric Project; Notice of Availability of...Impact Statement for the Martin Dam Hydroelectric Project and Intention To Hold Public...application for license for the Martin Dam Hydroelectric Project (FERC No. 349),...

2013-06-13

423

77 FR 14516 - Alabama Power Company, Martin Dam Hydroelectric Project; Notice of Proposed Revised Restricted...  

Federal Register 2010, 2011, 2012, 2013

...Alabama Power Company, Martin Dam Hydroelectric Project; Notice of Proposed Revised...of Historic Places at the Martin Dam Hydroelectric Project. The Programmatic Agreement...pursuant to section 106 for the Martin Dam Hydroelectric Project would be fulfilled...

2012-03-12

424

Seismic Stability Evaluation of Folsom Dam and Reservoir Project. Report 6. Right and Left Wing Dams.  

National Technical Information Service (NTIS)

The man-made water retaining structures at the Folsom Dam and Reservoir Project, located on the American River about 20 miles upstream of the city of Sacramento, California, have been evaluated for their seismic safety in the event of a Magnitude 6.5 eart...

D. E. Yule D. J. Elton M. E. Hynes R. E. Wahl

1989-01-01

425

Seismic Stability Evaluation of Folsom Dam and Reservoir Project. Report 3. Concrete Gravity Dam.  

National Technical Information Service (NTIS)

The man-made water retaining structures at the Folsom Dam and Reservoir Project, located on the American River about 20 miles upstream of the City of Sacramento, CA, have been evaluated for their seismic safety in the event of a magnitude 6.5 earthquake o...

J. M. Nau R. L. Hall S. C. Woodson

1989-01-01

426

Dams. Bulletin of the Technical Service of Electric Power and Big Dams.  

National Technical Information Service (NTIS)

Three papers were selected in this issue of the bulletin of the Technical Service of Electric Power and Big Dams. The first one concerns the experience feedback gained from the accident of the Drac river near Grenoble (France) due to a spillover at the No...

1996-01-01

427

Social impacts of Brazil's Tucurui Dam  

SciTech Connect

The Tucurui Dam, which blocked the Tocantins River in 1984 in Brazil's eastern Amazonian state of Para, is a continuing source of controversy. Most benefits of the power go to aluminum smelting companies, where only a tiny amount of employment is generated. Often presented by authorities as a model for hydroelectric development because of the substantial power that it produces, the project's social and environmental impacts are also substantial. Examination of Tucurui reveals a systematic overestimation of benefits and underestimation of impacts as presented by authorities. Tucurui offers many as-yet unlearned lessons for hydroelectric development in Amazonia.

Fearnside, P.M.

1999-11-01

428

Earthquake safety assessment of concrete arch and gravity dams  

NASA Astrophysics Data System (ADS)

Based on research studies currently being carried out at Dalian University of Technology, some important aspects for the earthquake safety assessment of concrete dams are reviewed and discussed. First, the rate-dependent behavior of concrete subjected to earthquake loading is examined, emphasizing the properties of concrete under cyclic and biaxial loading conditions. Second, a modified four-parameter Hsieh-Ting-Chen viscoplastic consistency model is developed to simulate the rate-dependent behavior of concrete. The earthquake response of a 278m high arch dam is analyzed, and the results show that the strain-rate effects become noticeable in the inelastic range. Third, a more accurate non-smooth Newton algorithm for the solution of three-dimensional frictional contact problems is developed to study the joint opening effects of arch dams during strong earthquakes. Such effects on two nearly 300m high arch dams have been studied. It was found that the canyon shape has great influence on the magnitude and distribution of the joint opening along the dam axis. Fourth, the scaled boundary finite element method presented by Song and Wolf is employed to study the dam-reservoir-foundation interaction effects of concrete dams. Particular emphases were placed on the variation of foundation stiffness and the anisotropic behavior of the foundation material on the dynamic response of concrete dams. Finally, nonlinear modeling of concrete to study the damage evolution of concrete dams during strong earthquakes is discussed. An elastic-damage mechanics approach for damage prediction of concrete gravity dams is described as an example. These findings are helpful in understanding the dynamic behavior of concrete dams and promoting the improvement of seismic safety assessment methods.

Lin, Gao; Hu, Zhiqiang

2005-12-01

429

The impact of the Aznalcóllar mine tailing spill on groundwater.  

PubMed

As a consequence of a mine tailing dam collapse on the 25th April 1998, more than 4000 ha of the Guadiamar riverflat and farmlands were flooded by 4 hm3 of sulphide slurry. A number of open wells (12 of the 47 analyzed) were also flooded and the water was contaminated. Before the spill, the groundwater in the aquifers was of calcium-carbonate and calcium-sulphate type, with moderate mineralisation and near neutral pH. With the exception of some of the wells close to the mine, this groundwater had a low concentration of the metals associated with the Aznalcóllar mine. After the flood the following metals had anomalous concentrations in well water: Zn, Mn, Pb, Co, Cd and Tl. Of these, Zn seems to be the best tracer of the contamination, owing to its high concentrations. During the 5 months following the spill, water from the unflooded wells did not show an increase in metal concentration. Apart from some exceptions in August, the metal concentration in the affected wells showed a progressive decrease reaching levels closer to those in the wells free from contamination. Nevertheless, in the following dry seasons the draw-down of the water level may lead to exposure and weathering of sulphides in the wells, which could cause an increase in pollution. Therefore, thorough cleaning of all highly contaminated wells is strongly recommended. PMID:10635581

Manzano, M; Ayora, C; Domenech, C; Navarrete, P; Garralon, A; Turrero, M J

1999-12-01

430

Failure-Space  

Microsoft Academic Search

Multiple perspectives are presented on failure-event-chain analysis and failure cause categorization followed by description of a systems engineering framework for failure evaluation. The framework consists of engineering and organizational elements typically within the program manager span of control. The systems engineering lens is then used to evaluate 50 space system failures. The high level mapping of failure attributes (causal root

J. Steven Newman

2001-01-01

431

Thermal effects of dams in the Willamette River basin, Oregon  

USGS Publications Warehouse

Methods were developed to assess the effects of dams on streamflow and water temperature in the Willamette River and its major tributaries. These methods were used to estimate the flows and temperatures that would occur at 14 dam sites in the absence of upstream dams, and river models were applied to simulate downstream flows and temperatures under a no-dams scenario. The dams selected for this study include 13 dams built and operated by the U.S. Army Corps of Engineers (USACE) as part of the Willamette Project, and 1 dam on the Clackamas River owned and operated by Portland General Electric (PGE). Streamflows in the absence of upstream dams for 2001-02 were estimated for USACE sites on the basis of measured releases, changes in reservoir storage, a correction for evaporative losses, and an accounting of flow effects from upstream dams. For the PGE dam, no-project streamflows were derived from a previous modeling effort that was part of a dam-relicensing process. Without-dam streamflows were characterized by higher peak flows in winter and spring and much lower flows in late summer, as compared to with-dam measured flows. Without-dam water temperatures were estimated from measured temperatures upstream of the reservoirs (the USACE sites) or derived from no-project model results (the PGE site). When using upstream data to estimate without-dam temperatures at dam sites, a typical downstream warming rate based on historical data and downstream river models was applied over the distance from the measurement point to the dam site, but only for conditions when the temperature data indicated that warming might be expected. Regressions with measured temperatures from nearby or similar sites were used to extend the without-dam temperature estimates to the entire 2001-02 time period. Without-dam temperature estimates were characterized by a more natural seasonal pattern, with a maximum in July or August, in contrast to the measured patterns at many of the tall dam sites where the annual maximum temperature typically occurred in September or October. Without-dam temperatures also tended to have more daily variation than with-dam temperatures. Examination of the without-dam temperature estimates indicated that dam sites could be grouped according to the amount of streamflow derived from high-elevation, spring-fed, and snowmelt-driven areas high in the Cascade Mountains (Cougar, Big Cliff/Detroit, River Mill, and Hills Creek Dams: Group A), as opposed to flow primarily derived from lower-elevation rainfall-driven drainages (Group B). Annual maximum temperatures for Group A ranged from 15 to 20 degree(s)C, expressed as the 7-day average of the daily maximum (7dADM), whereas annual maximum 7dADM temperatures for Group B ranged from 21 to 25 degrees C. Because summertime stream temperature is at least somewhat dependent on the upstream water source, it was important when estimating without-dam temperatures to use correlations to sites with similar upstream characteristics. For that reason, it also is important to maintain long-term, year-round temperature measurement stations at representative sites in each of the Willamette River basin's physiographic regions. Streamflow and temperature estimates downstream of the major dam sites and throughout the Willamette River were generated using existing CE-QUAL-W2 flow and temperature models. These models, originally developed for the Willamette River water-temperature Total Maximum Daily Load process, required only a few modifications to allow them to run under the greatly reduced without-dam flow conditions. Model scenarios both with and without upstream dams were run. Results showed that Willamette River streamflow without upstream dams was reduced to levels much closer to historical pre-dam conditions, with annual minimum streamflows approximately one-half or less of dam-augmented levels. Thermal effects of the dams varied according to the time of year, from cooling in mid-summer to warm

Rounds, Stewart A.

2010-01-01

432

Critical points and transitions in an electric power transmission model for cascading failure blackouts  

Microsoft Academic Search

Cascading failures in large-scale electric power transmission systems are an important cause of blackouts. Analysis of North American blackout data has revealed power law (algebraic) tails in the blackout size probability distribution which suggests a dynamical origin. With this observation as motivation, we examine cascading failure in a simplified transmission system model as load power demand is increased. The model

B. A. Carreras; V. E. Lynch; I. Dobson; D. E. Newman

2002-01-01

433

The Weibull–Pareto Composite Family with Applications to the Analysis of Unimodal Failure Rate Data  

Microsoft Academic Search

The Weibull distribution is composited with Pareto model to obtain a flexible, reliable long-tailed parametric distribution for modeling unimodal failure rate data. The hazard function of the composite family accommodates decreasing and unimodal failure rates, which are separated by the boundary line of the space of shape parameter, gamma, when it equals to a known constant. The least square and

Kahadawala Cooray

2009-01-01

434

Comet tail formation: Giotto observations  

SciTech Connect

The process of mass loading of the solar wind by cometary ions, which forms comet tails, has been observed throughout the coma of comet Halley. Three distinct regimes were found where the nature of the energy and momentum coupling between solar wind and cometary ions is different. Outside the bow shock, where there is little angular scattering of the freshly ionized particles, the coupling is described by the simple pickup trajectory and the energy is controlled by the angle between the flow and the magnetic field. Just inside the bow shock, there is considerable scattering accompanied by another acceleration process which raises some particle energies well above the straightforward pickup value. Finally, closer to the nucleus, the amount of scattering decreases and the coupling is once more controlled by the magnetic field direction. 4 refs., 3 figs.

Wilken, B.; Jockers, K.; Johnstone, A.; Coates, A.; Heath, J.; Formisano, V.; Amata, E.; Winningham, J.D.; Thomsen, M.; Bryant, D.A.

1986-01-01

435

59. Downstream view of Waddell Dam showing buttress ties, crane, ...  

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

59. Downstream view of Waddell Dam showing buttress ties, crane, housing over penstock outlet (left) and storage building (right). Photographer Mark Durben, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

436

53. Humbug Creek looking downstream from Humbug Diversion Dam. Retaining ...  

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

53. Humbug Creek looking downstream from Humbug Diversion Dam. Retaining wall for canal is visible beginning at left center. Photographer James Eastwood, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

437

63. Upstream face of Waddell Dam as viewed from the ...  

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

63. Upstream face of Waddell Dam as viewed from the west abutment. Crane at center is used to service the penstock intake. Photographer Mark Durben. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

438

The Removal of the Edwards Dam: Renewed Debates  

NSDL National Science Digital Library

On July 1, 1999, the destruction of the Edwards Dam in Maine began, marking the first case of an order to remove a hydroelectric dam against the owner's wishes. Dams were constructed to provide mechanical power, and later electrical power, mainly for saw, grist, and textile mills. These mills were a substantial asset to the economy by providing jobs, but as the mills closed, the economic necessity of dams diminished. Ecologists have been identifying the environmental benefits fish and wildlife receive when rivers are restored by removing dams. The Edwards River is in the process of being restored, but the restoration of another, much larger river, the Snake River in Oregon, continues to be a source of debate. Ecologists and biologists believe restoring the Snake River will help the endangered wild salmon regain their numbers. Agricultural and industrial users of the Snake River argue that the dam still provides substantial economic benefits. The eight resources listed for this In the News topic provide current information on the Edwards dam removal, the Snake River debates, and general information on dams.

Schultz, Jennifer J.

439

86. LOCK AND DAM NUMBERS 1013, 1618, 2022. INCLUSIVEGASOLINE SERVICE ...  

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

86. LOCK AND DAM NUMBERS 10-13, 16-18, 20-22. INCLUSIVE-GASOLINE SERVICE PUMPS (ML-10-37/10/1-FS), December 1938. - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

440

33 CFR 117.705 - Beaver Dam Creek.  

Code of Federal Regulations, 2013 CFR

...Waters 1 2013-07-01 2013-07-01 false Beaver Dam Creek. 117.705 Section 117.705 Navigation and...Specific Requirements New Jersey § 117.705 Beaver Dam Creek. The draw of the Ocean County bridge,...

2013-07-01

441

5. General view of the Glens Falls Dam from the ...  

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

5. General view of the Glens Falls Dam from the vicinity of its southeast end. The log chute is in the background. Facing west-southwest. - Glens Falls Dam, 100' to 450' West of U.S. Route 9 Bridge Spanning Hudson River, Glens Falls, Warren County, NY

442

Sedimentation in bottomland hardwoods downstream of an east Texas dam  

Microsoft Academic Search

Dams and reservoirs are often efficient sediment traps, and conventional wisdom holds that fluvial sediment supplies are reduced well downstream. However, there are reasons to question the extent to which fluvial and alluvial sediment supplies are reduced more than a few kilometers downstream of dams. Sedimentation in bottomlands of Loco Bayou, east Texas, was investigated at a site less than

J. Phillips

2001-01-01

443

Effect of reservoir bottom on earthquake response of concrete dams  

Microsoft Academic Search

The absorption of hydrodynamic pressure waves at the reservoir bottom has dominant effects on the structural response of the dam when subjected to ground motion. In the present study, a model is proposed for the absorption effects of the reservoir bottom in the earthquake analysis of dams. The model utilizes the wave reflection coefficient approach and is based on the

Kianoosh Hatami

1997-01-01

444

5. DIABLO DAM: DETAIL VIEW OF RELIEF VALVES AT ELEVATION ...  

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

5. DIABLO DAM: DETAIL VIEW OF RELIEF VALVES AT ELEVATION 1044. VALVE IN FOREGROUND IS A BUTTERFLY VALVE SIX FEET IN DIAMETER; VALVE TO THE REAR IS A JOHNSON-TYPE NEEDLE VALVE BOTH VALVES WERE MANUFACTURED BY THE PELTON WATER WHEEL COMPANY, 1989. - Skagit Power Development, Diablo Dam, On Skagit River, 6.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

445

"No. 146. Looking west along dam. East side abutment." Note ...  

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

"No. 146. Looking west along dam. East side abutment." Note sluiceway and headgates at center rear of photograph; cofferdam at center right; and the screening and mixing plant at lower right. Rail cars are on the railroad grade in background - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

446

Attitudes of Operative Dentistry Faculty toward Rubber Dam Isolation.  

ERIC Educational Resources Information Center

Dental faculty responses (N=332) to a survey concerning use of rubber dams for excluding fluids from the working field in operative dentistry procedures indicated students receive adequate instruction in rubber dam use and are proficient at graduation, though motivating students to its use is problematic and patient resistance a factor. (MSE)

Brackett, William W.; And Others

1989-01-01

447

Correlations among the WISC-R, PIAT, and DAM.  

ERIC Educational Resources Information Center

The WISC-R, PIAT, and DAM were examined to ascertain relationships among the three instruments. Correlations indicate that information yielded by the PIAT may be obtained through WISC-R results, while the DAM may be tapping other abilities not adequately assessed by either of the other two measures. (Author)

White, Thomas H.

1979-01-01

448

View of Lake Sabrina Dam showing wooden planks along the ...  

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

View of Lake Sabrina Dam showing wooden planks along the upstream face and concrete base added in 1916/1917 and showing the iron grating covering upstream side of outlet structure is visible at lower photo center, view northeast - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

449

5. VIEW SHOWING HORSE MESA DAM UNDER CONSTRUCTION. THREE PENSTOCKS ...  

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

5. VIEW SHOWING HORSE MESA DAM UNDER CONSTRUCTION. THREE PENSTOCKS ARE AT CENTER AND CONCRETE TOWER LINES. AGGREGATE OPERATION IS VISIBLE ABOVE CONSTRUCTION SITE July 22, 1926 - Horse Mesa Dam, Salt River, 65 miles East of Phoenix, Phoenix, Maricopa County, AZ

450

GENERAL CLOSEUP AERIAL OF ELWHA DAM AND POWER HOUSE LOOKING ...  

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

GENERAL CLOSE-UP AERIAL OF ELWHA DAM AND POWER- HOUSE LOOKING DOWN ON SURGE TANK, BIFURCATED PENSTOCK, SPILLWAYS, AND NORTH END OF RESERVOIR. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

451

9. 'CRIB DAM IN LAKE FORK RIVER AT HEADING OF ...  

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

9. 'CRIB DAM IN LAKE FORK RIVER AT HEADING OF LAKE FORK CANAL, UINTAH PROJECT. TWO SLUICEWAYS TWENTY FEET WIDE HAVE BEEN LEFT IN THE DAM TO PASS BOULDERS DURING HIGH WATER. THESE SLUICEWAYS ARE CLOSED BY LOGS AND HAY DURING LOW WATER.' Date unknown - Irrigation Canals in the Uinta Basin, Duchesne, Duchesne County, UT

452

VIEW OF WARRIOR RIVER, OLIVER LOCK AND DAM LOOKING NORTHEAST, ...  

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

VIEW OF WARRIOR RIVER, OLIVER LOCK AND DAM LOOKING NORTHEAST, LURLEEN WALLACE BRIDGE IN BACKGROUND, GULF MOBILE & OHIO RAILROAD BRIDGE IN FRONT OF LURLEEN WALLACE BRIDGE, NORTHPORT LEFT SIDE, TUSCALOOSA RIGHT SIDE, UNIVERSITY OF ALABAMA IN RIGHT BACKGROUND. - William Baker Oliver Lock & Dam, Spans Warrior River between Tuscaloosa & Northport, Tuscaloosa, Tuscaloosa County, AL

453

6. View of lower dam masonry pier which houses the ...  

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

6. View of lower dam masonry pier which houses the sluice. Photograph taken from cut stone apron edging in Millstone Creek. VIEW WEST. - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

454

4. Side view of lower dam showing crest, overspill and ...  

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

4. Side view of lower dam showing crest, overspill and apron. Photograph taken from east side of Millstone Creek. VIEW SOUTHWEST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

455

11. Photographic copy of original Lower Dam for Loleta Camp ...  

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

11. Photographic copy of original Lower Dam for Loleta Camp Ground drawing by Paul Wakefield, 1933 (original in possession of United States Department of Agriculture-Forest Service-Allegheny National Forest). - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

456

3. Side view of lower dam showing crest, overspill and ...  

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

3. Side view of lower dam showing crest, overspill and apron. Photograph taken from west side of Millstone Creek. VIEW NORTHEAST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

457

2. Rear view of upper dam with Millstone Creek flowing ...  

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

2. Rear view of upper dam with Millstone Creek flowing over overspill. Photograph taken from west bank of Millstone Creek. VIEW SOUTHEAST - Loleta Recreation Area, Upper Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

458

5. Rear view of lower dam showing crest, masonry pier ...  

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

5. Rear view of lower dam showing crest, masonry pier and sluice gate. Photograph taken from east bank of the sandy beach. VIEW SOUTH - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

459

9. Photographic copy of historic photograph showing lower dam without ...  

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

9. Photographic copy of historic photograph showing lower dam without stone apron and water flowing over the overspill. Date and photographer unknown. (original in possession of United States Department of Agriculture-Forest Service-Allegheny National Forest) VIEW WEST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

460

5. LOOKING WEST ALONG THE AXIS OF THE DAM TOWARD ...  

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

5. LOOKING WEST ALONG THE AXIS OF THE DAM TOWARD THE OUTLET STRUCTURE. HAND OPERATED MECHANICAL TAMPERS ARE COMPACTING THE FILL ALONG THE STEEL SHEET PILING CUTOFF WALL IN THE FOREGROUND. Volume XIX, No. 6, April 12, 1940. - Prado Dam, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

461

Richard B. Russell Dam and Lake Oxygen Injection System.  

National Technical Information Service (NTIS)

When completed, the Richard B. Russell Dam and Lake will be a multipurpose project designed to provide hydropower, some flood control, recreation, and has a potential for water supply. The dam will consist of a 195-foot high, 1,900-foot long concrete grav...

J. W. Gallagher

1984-01-01

462

2. Photocopied June 1978 'THE IRON DAM.' VIEW OF THE ...  

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

2. Photocopied June 1978 'THE IRON DAM.' VIEW OF THE IRON DAM, THE OUTCROPPING OF THE ORE FOUND IN 1826 BY HENDERSON. FURNISHED WATER TO SAWMILL. SOURCE: BENSON LOSSING, THE HUDSON, FROM THE WILDERNESS TO THE SEA, TROY, NEW YORK, 1866, p. 25 - Adirondack Iron & Steel Company, New Furnace, Hudson River, Tahawus, Essex County, NY

463

1. INTAKE DAM NO. 1 AT HEAD OF SYSTEM (600 ...  

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

1. INTAKE DAM NO. 1 AT HEAD OF SYSTEM (600 ALTITUDE). CONSTRUCTED WITH CONCRETE AND RUBBLE MASONRY IN 1948. INCLUDES INTAKE SCREEN AT LEFT AND SLUICE GATE AT RIGHT. TWO 8" CAST-IRON PIPES CARRY WATER FROM THE INTAKE TO THE OLD DAM (FORMER INTAKE) DOWN LINE. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

464

95. AVALON DAM Photographic copy of construction drawing dated ...  

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

95. AVALON DAM - Photographic copy of construction drawing dated January 19, 1911 1912? (from Record Group 115, Box 17, Denver Branch of the National Archives, Denver) BALANCING DEVICE FOR 21 FT. DIA. CYLINDER GATE - Carlsbad Irrigation District, Avalon Dam, On Pecos River, 4 miles North of Carlsbad, Carlsbad, Eddy County, NM

465

PORTFOLIO RISK ASSESSMENT OF SA WATER'S LARGE DAMS  

Microsoft Academic Search

This paper summarises the Portfolio Risk Assessment (PRA) process that was implemented for SA Water's 17 large dams, the information obtained from the PRA, and its use by SA Water. The PRA was designed to provide a baseline assessment of the existing dams and an initial prioritisation of future investigations and possible risk reduction measures. The PRA comprised a reconnaissance-level

David S. Bowles; Andrew M. Parsons; Loren R. Anderson; Terry F. Glover

1999-01-01

466

3. CREST OF THE SOUTH CHANNEL DAM, SHOWING BLOCK HOUSE ...  

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

3. CREST OF THE SOUTH CHANNEL DAM, SHOWING BLOCK HOUSE (NOT ORIGINAL) COVERING THE ELECTRICALLY POWERED GATE-LIFTING MECHANISM THAT REPLACED THE ORIGINAL HAND-OPERATED LIFTING DEVICE, LOOKING NORTH. - Washington Water Power Company Post Falls Power Plant, South Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

467

Oblique overview, looking northnortheast, of south elevation of diversion dam, ...  

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

Oblique overview, looking north-northeast, of south elevation of diversion dam, showing all seven rollers, four gatehouses, and four piers. Note also the paved west river bank and training wall - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

468

1. VIEW NORTHEAST OF DAM AND HEADWORKS (LEFT), FROM SDK ...  

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

1. VIEW NORTHEAST OF DAM AND HEADWORKS (LEFT), FROM SDK OF WEST CANADA CREEK, WITH REMAINS OF 12 FOOT PIPELINE AND HIGH-LEVEL INTAKE PIPE (EXTREME LEFT) - Trenton Falls Hydroelectric Station, Dam & Headworks, On west bank of West Canada Creek, along Trenton Falls Road, 2 miles north of New York Route 28, Trenton Falls, Oneida County, NY

469

30. VIEW SOUTHEAST ON SHELTON SIDE OF DAM DURING DEWATERING. ...  

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

30. VIEW SOUTHEAST ON SHELTON SIDE OF DAM DURING DEWATERING. CORNER OF SHELTON LOCKS AND MITRE GATES AT RIGHT. - Ousatonic Water Power Company, Dam & Canals, CT Routes 34 & 108, 1 mile North of Derby-Shelton Bridge, Derby, New Haven County, CT

470

28. VIEW NORTH TOWARD DERBY DURING DEWATERING. DAM IN CENTER ...  

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

28. VIEW NORTH TOWARD DERBY DURING DEWATERING. DAM IN CENTER OF PICTURE WITH SHELTON GATEHOUSE ON LEFT AND DERBY GATEHOUSE ON RIGHT. - Ousatonic Water Power Company, Dam & Canals, CT Routes 34 & 108, 1 mile North of Derby-Shelton Bridge, Derby, New Haven County, CT

471

The Three Gorges Dam Affects Regional Precipitation  

NASA Technical Reports Server (NTRS)

Issues regarding building large-scale dams as a solution to power generation and flood control problems have been widely discussed by both natural and social scientists from various disciplines, as well as the policy-makers and public. Since the Chinese government officially approved the Three Gorges Dam (TGD) projects, this largest hydroelectric project in the world has drawn a lot of debates ranging from its social and economic to climatic impacts. The TGD has been partially in use since June 2003. The impact of the TGD is examined through analysis of the National Aeronautics and Space Administration (NASA) Tropical Rainfall Measuring Mission (TRMM) rainfall rate and Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature and high-resolution simulation using the Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) fifth-generation Mesoscale Model (MM5). The independent satellite data sets and numerical simulation clearly indicate that the land use change associated with the TGD construction has increased the precipitation in the region between Daba and Qinling mountains and reduced the precipitation in the vicinity of the TGD after the TGD water level abruptly rose from 66 to 135 m in June 2003. This study suggests that the climatic effect of the TGD is on the regional scale (approx.100 km) rather than on the local scale (approx.10 km) as projected in previous studies.

Wu, Liguang; Zhang, Qiang; Jiang, Zhihong

2006-01-01

472

Stability properties of a cometary plasma tail  

Microsoft Academic Search

The linear stability of the plasma tail of a comet is numerically investigated. Effects both of finite resistivity and of velocity shear are taken into account. The tail appears to be unstable against Kelvin-Helmholtz-like modes in which a certain amount of reconnection occurs. Because of the velocity flow shear the perturbation extends far beyond the singular layer and affects in

Francesco Malara; Giorgio Einaudi; Andre Mangeney

1989-01-01

473

CISLUNAR GEOMAGNETIC TAIL GRADIENT IN 1967  

Microsoft Academic Search

In this letter, the geomagnetic tail field gradient during the summers of 1966 and 1967 is examined for secular change. We use data from Ames magnetometers on Explorers 33 and 35. The 1967 data are compared with the earlier published 1966. Explorer 33 results [Mihalo. v et al., 1968]. Secular change of the tail field magnitude gradient is not found

J. D. Mihalov; C. P. Sonett

1968-01-01

474

Tale of tails: Parallelism and prehensility  

Microsoft Academic Search

The occurrence of prehensile tails among only five platyrrhine genera-Cebus, Alouatta, Lagothrix, Ateles, and Bmchyteles-might be inter- preted as evidence that these are a closely related, possibly monophyletic group. In the absence of behavioral data, it is impossible to test whether all possess equivalent biological roles; such would lend credence to the idea that their tails evolved from an homologous,

Alfred L. Rosenberger

1983-01-01

475

Unified Approach to Estimating Tail Behavior.  

National Technical Information Service (NTIS)

Tail estimators are proposed which make minimal assumptions and let the data dictate the form of the probability model. These estimators use only the observations in the tail and are based on a unifying density-quantile model. The fundamental result in th...

S. D. Grimshaw

1989-01-01

476

Factors influencing radon attenuation by tailing covers  

Microsoft Academic Search

The US NRC, in its Generic Environmental Impact Statement on uranium milling has specified that the radon flux escaping a uranium mill tailings pile will be reduced to pCi\\/m² s by application of covering layers of soils and clays. These covers present a radon diffusion barrier, which sufficiently increases the time required for radon passage from the tailings to the

W. B. Silker; V. C. Rogers

1981-01-01

477

EXPERIMENTAL RESEARCH ON HELICOPTER TAIL SHAKE PHENOMENON  

Microsoft Academic Search

Helicopter tail shake phenomenon is still remained as a long dragged issue that adversely affected the overall performance, occupants' comfort and handling qualities of helicopter. The objective of this research is to improve basic understanding of the viscous unsteady flow phenomenon observed behind the helicopter tail part. For this, a wind tunnel test had been conducted with a rigid 14%

Iskandar Shah Ishak; Shuhaimi Mansor; Tholudin Mat Lazim

478

Efficient Algorithms for Computing Sommerfeld Integral Tails  

Microsoft Academic Search

Sommerfeld-integrals (SIs) are ubiquitous in the analysis of problems involving antennas and scatterers embedded in planar multilayered media. It is well known that the oscillating and slowly decaying nature of their integrands makes the numerical evaluation of the SI real-axis tail segment a very time consuming and computationally expensive task. Therefore, SI tails have to be specially treated. In this

Ruzica Golubovic; Athanasios G. Polimeridis; Juan R. Mosig

2012-01-01

479

The histone tails of the nucleosome  

Microsoft Academic Search

Reversible acetylation of core histone tails plays an important role in the regulation of eukaryotic transcription, in the formation of repressive chromatin complexes, and in the inactivation of whole chromosomes. The high-resolution X-ray structure of the nucleosome core particle, as well as earlier evidence, suggests that the histone tails are largely responsible for the assembly of nucleosomes into chromatin fibers

Karolin Luger; Timothy J Richmond

1998-01-01

480

CONFIGURATION AND RECONNECTION OF THE GEOMAGNETIC TAIL  

Microsoft Academic Search

A description of certain aspects of the geomagnetic tail is made using data from the Ames magnetometer on the Explorer 33 satellite. The general shape corresponds with eaxlier fi