bluuebunny/crossref_metadata_2025 huggingface dataset:
RAINGAGE NETWORK DESIGN USING NEXRAD PRECIPITATION ESTIMATES1
Authors: Bradley A. Allen , Peters‐Lidard Christa , Nelson Brian R. , Smith James A. , Young C. Bryan
Published: June 2007

ABSTRACT: A general framework is proposed for using precipitation estimates from NEXRAD weather radars in raingage network design. NEXRAD precipitation products are used to represent space time rainfall fields, which can be sampled by hypothetical raingage networks. A stochastic model is used to simulate gage observations based on the areal average precipitation for radar grid cells. The stochastic model accounts for subgrid variability of precipitation within the cell and gage measurement errors. The approach is ideally suited to raingage network design in regions with strong climatic variations in rainfall where conventional methods are sometimes lacking. A case study example involving the estimation of areal average precipitation for catchments in the Catskill Mountains illustrates the approach. The case study shows how the simulation approach can be used to quantify the effects of gage density, basin size, spatial variation of precipitation, and gage measurement error, on network estimates of areal average precipitation. Although the quality of NEXRAD precipitation products imposes limitations on their use in network design, weather radars can provide valuable information for empirical assessment of rain‐gage network estimation errors. Still, the biggest challenge in quantifying estimation errors is understanding subgrid spatial variability. The results from the case study show that the spatial correlation of precipitation at subgrid scales (4 km and less) is difficult to quantify, especially for short sampling durations. Network estimation errors for hourly precipitation are extremely sensitive to the uncertainty in subgrid spatial variability, although for storm total accumulation, they are much less sensitive.
CLIMATIC AND HYDROLOGIC VARIABILITY IN A COASTAL WATERSHED OF SOUTHWESTERN BRITISH COLUMBIA1
Authors: Kiffney Peter M. , Bull Jennifer P. , Feller Michael C.
Published: June 2007

ABSTRACT: Climate data from the Malcolm Knapp Research Forest (MKRF) in the Coast Range mountains of southwestern British Columbia were used to examine relationships between climate and hydrology and variations in the El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Air and water temperatures were higher and precipitation was lower during in‐phase or warm PDO/E1 Niño events than in other years. In contrast, in‐phase or cool PDO/La Niña years were generally cooler and wetter than other years. Precipitation and East Creek discharge were positively related to the Southern Oscillation Index (SOI) and negatively related to the PDO index. Conversely, air and water temperatures were negatively related to the SOI and positively related to the PDO index. Differences in precipitation and air temperature were also evident at longer time scales when separated by PDO phase. Because of drier conditions during in‐phase El Niño events, the flow of organic matter from East Creek to downstream portions of the channel network was lower compared to other years. This reduction has implications for downstream communities, as these subsidies provide a major source of energy for stream food webs. Therefore, short term and long term shifts in climate, discharge, and water temperature may have profound impacts on the ecology of Pacific Northwest (PNW) watersheds due to changes in a number of ecosystem processes such as altered flux of organic matter from headwater streams to larger rivers.
HEAVY RAINSTORMS IN CHICAGO: INCREASING FREQUENCY, ALTERED IMPACTS, AND FUTURE IMPLICATIONS1
Authors: Changnon Stanley A. , Westcott Nancy E.
Published: June 2007

ABSTRACT: Operations of a dense raingage network in the Chicago area since 1989 provided data to assess the temporal and spatial distributions of heavy rainstorms. The 12‐year average was 4.4 storms per year, 40 percent more than in the 1948 to 1980 period, reflecting an ongoing Midwestern increase in heavy rains. The total rainfall from the 53 heavy rainstorms maximized over the city, reflecting previous observations that the influence of the city and Lake Michigan on the atmosphere causes an increase in heavy rains. Impacts from the record high number of eight storms in 2001 revealed that efforts to control flooding including the Deep Tunnel system, had reduced street and basement flooding in the moderate intensity storms, but the two most intense storms, each with 100‐year rainfall values, led to excessive flooding and a need to release flood waters into Lake Michigan. Results suggest continuing increases in the number of heavy rainstorms in future years, which has major implications for water managers in Chicago and elsewhere.
ADJUSTMENT OF STREAM CHANNEL CAPACITY FOLLOWING DAM CLOSURE, YEGUA CREEK, TEXAS1
Authors: Chin Anne , Harris Daniel L. , Trice Todd H. , Given Jeffrey L.
Published: June 2007

ABSTRACT: In Yegua Creek, a principal tributary of the Brazos River in Texas, surveys of a 19 km channel reach downstream of Somerville Dam show that channel capacity decreased by an average of 65 percent in a 34 year period following dam closure. The decrease corresponds with an approximately 85 percent reduction in annual flood peaks. Channel depth has changed the most, decreasing by an average of 61 percent. Channel width remained stable with an average decrease of only 9 percent, reflecting cohesive bank materials along with the growth of riparian vegetation resulting from increased low flows during dry summer months. Although large changes in stream channel geometry are not uncommon downstream of dams, such pronounced reductions in channel capacity could have long‐term implications for sediment delivery through the system.
EFFECTS OF DAM IMPOUNDMENT ON THE FLOOD REGIME OF NATURAL FLOODPLAIN COMMUNITIES IN THE UPPER CONNECTICUT RIVER1
Authors: Nislow Keith H. , Magilligan Francis J. , Fassnacht Heidi , Bechtel Doug , Ruesink Ana
Published: June 2007

ABSTRACT: Understanding the effects of dams on the inundation regime of natural floodplain communities is critical for effective decision making on dam management or dam removal. To test the implications of hydrologic alteration by dams for floodplain natural communities, we conducted a combined field and modeling study along two reaches in the Connecticut River Rapids Macrosite (CRRM), one of the last remaining flowing water sections of the Upper Connecticut River. We surveyed multiple channel cross sections at both locations and concurrently identified and surveyed the elevations of important natural communities, native species of concern, and nonnative invasive species. Using a hydrologic model, HEC‐RAS, we routed estimated pre‐and post‐impoundment discharges of different design recurrence intervals (two year through 100 year floods) through each reach to establish corresponding reductions in elevation and effective wetted perimeter following post‐dam discharge reductions. By comparing (1) the frequency and duration of flooding of these surfaces before and after impoundment and (2) the total area flooded at different recurrence intervals, our goal was to derive a spatially explicit assessment of hydrologic alteration, directly relevant to natural floodplain communities.

Post‐impoundment hydrologic alteration profoundly affected the subsequent inundation regime, and this impact was particularly true of higher floodplain terraces. These riparian communities, which were flooded, on average, every 20 to 100 years pre‐impoundment, were predicted to flood at 100 ≫ 100 year intervals, essentially isolating them completely from riverine influence. At the pre‐dam five to ten year floodplain elevations, we observed smaller differences in predicted flood frequency but substantial differences in the total area flooded and in the average flood duration. For floodplain forests in the Upper Connecticut River, this alteration by impoundment suggests that even if other stresses facing these communities (human development, invasive exotics) were alleviated, this may not be sufficient to restore intact natural communities. More generally, our approach provides a way to combine site specific variables with long term gage records in assessing the restorative potential of dam removal.
ASSESSMENT USING GIS AND SEDIMENT ROUTING OF THE PROPOSED REMOVAL OF BALLVILLE DAM, SANDUSKY RIVER, OHIO1
Authors: Evans James E. , Levine Norman S. , Roberts Sheila J. , Gottgens Johan F. , Newman Diane M.
Published: June 2007

ABSTRACT: The proposed removal of Ballville Dam was assessed by (1) using a new Geographic Information Systems (GIS) based method for calculating reservoir sediment storage, (2) evaluating sediment properties and contamination from core data, and (3) assessing downstream impacts from sediment routing calculations. A 1903 (pre‐dam) map was manipulated using GIS to recreate the reservoir bathymetry at time of dam construction and used in combination with a detailed 1993 bathymetric survey to calculate sediment volumes and thickness. Reservoir sediment properties and geochemistry were determined from 14 sediment vibracores. Annual sedimentation rates varied from 1.7 to 4.3 g/cm2/yr based on Cesium‐137 (137Cs) and Lead‐210 (210Pb) geochronology and dated flood layers. The pore fluid geochemistry (Ba, Co, Cu, Mn) of four cores showed surficial enrichments in Cu, while Co and Mn show secondary peaks within the sediments. GIS calculations showed that a designed channel through the former reservoir able to accommodate the 10 percent Probable Maximum Flood (PMF) would require removing approximately 0.35 million m3 of sediment (27 percent of the reservoir fill), either by dredging at a cost of up to $6.3 million or by releasing fine grained sediment downstream. A sediment routing model was applied for the critical 6 km downstream using four cross sections. The sediment routing model predicts that, for flows exceeding minimum Mean Daily Flow (1924 to 1998 data), greater than 90 percent of this sediment would be transported through downstream reaches into Lake Erie (Sandusky Bay).
GEOMORPHIC ANALOGIES FOR ASSESSING PROBABLE CHANNEL RESPONSE TO DAM REMOVAL1
Authors: Doyle Martin W. , Stanley Emily H. , Harbor Jon M.
Published: June 2007

ABSTRACT: There is a pressing need for tools to predict the rates, magnitudes, and mechanisms by which sediment is removed from a reservoir following dam removal, as well as for tools to predict where this sediment will be deposited downstream and how it will impact downstream channel morphology. In the absence of adequate empirical data, a good initial approach is to examine the impacts of dam removal within the context of the geomorphic analogies of channel evolution models and sediment waves. Channel changes at two dam breaching sites in Wisconsin involved a succession of channel forms and processes consistent with an existing channel evolution model. Sediment transported downstream after removal of other dams suggests that reservoir sediment may be translated downstream either as a distinct wave or gradually eroded away. More extensive data collection on existing dam removals is warranted before undertaking the removal of a large number of dams. However, if removal is to proceed based on current knowledge, then geomorphic analogies can be used as the foundation for sediment management and stabilization schemes.
AN INTEGRATIVE APPROACH TOWARDS UNDERSTANDING ECOLOGICAL RESPONSES TO DAM REMOVAL: THE MANATAWNY CREEK STUDY1
Authors: Bushaw‐Newton Karen L. , Hart David D. , Pizzuto James E. , Thomson James R. , Egan Jennifer , Ashley Jeffrey T. , Johnson Thomas E. , Horwitz Richard J. , Keeley Melissa , Lawrence Joy , Charles Don , Gatenby Catherine , Kreeger Daniel A. , Nightengale Tim , Thomas Roger L. , Velinsky David J.
Published: June 2007

ABSTRACT: Dam removal has been proposed as an effective method of river restoration, but few integrative studies have examined ecological responses to the removal of dams. In 1999, we initiated an interdisciplinary study to determine ecological responses to the removal of a 2 m high dam on lower Manatawny Creek in southeastern Pennsylvania. We used an integrative monitoring program to assess the physical, chemical, and biological responses to dam removal. Following removal in 2000, increased sediment transport has led to major changes in channel form in the former impoundment and downstream reaches. Water quality did not change markedly following removal, probably because of the impoundment's short hydraulic residence time (less than two hours at base flow) and infrequent temperature stratification. When the impoundment was converted to a free flowing reach, the composition of the benthic macroinvertebrate and fish assemblages in this portion of Manatawny Creek shifted dramatically from lentic to lotic taxa. Some fish species inhabiting the free flowing reach downstream from the dam were negatively affected by large scale sediment transport and habitat alteration following dam removal, but this appears to be a short term response. Based on our observations and experiences in this study, we provide a list of issues to evaluate when considering future dam removals.
MAKING SMARTER ENVIRONMENTAL MANAGEMENT DECISIONS1
Authors: Gregory Robin S. , Keeney Ralph L.
Published: June 2007

ABSTRACT: This paper outlines a sound, practical approach for making more informed decisions about environmental policy choices. It emphasizes the importance of using a structured decision process to specify and organize values, use these values to create alternatives, and assess tradeoffs to help achieve a desired balance across key objectives. Although these decision making steps are based on common sense, they are often neglected or poorly carried out as part of the complex evaluations of natural resource options. We discuss several reasons for this frequent neglect of decision making principles and provide examples from recent water use planning projects to demonstrate some of the benefits of using a structured, decision focused approach: new and better solutions, increased and more productive participation by stakeholders, and greater defensibility and acceptance of the resource management evaluation process and its conclusions.
INTERACTIVE DISTRIBUTED CONSERVATION PLANNING1
Authors: Brown Elaine M. , Ouyang Da , Asher A. Jeremiah , Bartholic Jon F.
Published: June 2007

ABSTRACT: In the environmental and agricultural conservation planning process, more efficient and effective tools are needed for planners to assist private landowners with making wiser land use decisions. Current methods are slow, inefficient, and costly. Scientific techniques have not been fully implemented within the planning process, yet such plans are increasingly needed to meet water quality and Total Maximum Daily Load (TMDL) requirements. The objectives of this study are to (a) utilize the web for accessing an integrated science‐based land use decision support system; (b) link decision tools, models, and databases to the user via the web; (c) link distributed models and databases for enhanced planning efficiency; and (d) integrate the above into an easily usable and readily accessible system. The procedures resulting in the initial design involved planning expertise and focus groups' input. The system was developed in partnership with the Natural Resources Conservation Service of the U.S. Department of Agriculture and several state agencies. A survey of 150 certified conservation planners, the end users, was conducted to identify the data sets and planning tools needed. Data, tools, and models then were selected and integrated into a web accessible system. Specifically, the first generation used a web interactive Geographic Information System (GIS) that overlaid onto digital orthoquads and/or soils polygons field boundaries, transportation, hydrologic features (such as drains, rivers, lakes, etc.), and high pesticide risk runoff or infiltration areas. Conservation planners found they could save time with the system. Clients could access the system quickly to help them prepare for meeting with their planner. Previously acquiring GIS maps in some cases had been a lengthy process that limited use of the information in land use decisions.
INTEGRATING SCIENCE AND TECHNOLOGY TO SUPPORT STREAM NATURALIZATION NEAR CHICAGO, ILLINOIS1
Authors: Wade Rebecca J. , Rhoads Bruce L. , Rodriguez Jose , Daniels Melinda , Wilson David , Herricks Edwin E. , Bombardelli Fabian , Garcia Marcelo , Schwartz John
Published: June 2007

ABSTRACT: Many urban and suburban communities in the Midwest are seeking to establish sustainable, morphologically and hydraulically varied, yet dynamically stable fluvial systems that are capable of supporting healthy, biologically diverse aquatic ecosystems — a process known as stream naturalization. This paper describes an integrated research program that seeks to develop a scientific and technological framework to support two stream naturalization projects near Chicago, Illinois. The research program integrates theory and methods in fluvial geomorphology, aquatic ecology, hydraulic engineering and social theory. Both the conceptual and the practical challenges of that integration are discussed. Scientific and technical support emphasize the development of predictive tools to evaluate the performance of possible naturalization designs at scales most appropriate to community based projects. Social analysis focuses on place based evaluations of how communities formulate an environmental vision and then, through decision making, translate this vision into specific stream naturalization strategies. Integration of scientific and technical with social components occurs in the context of community based decision making as the predictive tools are employed by project scientists to help local communities translate their environmental visions into concrete environmental designs. Social analysis of this decision making process reveals how the interplay between the community's vision of what they want the watershed to become, and the scientific perspective on what the watershed can become to achieve the community's environmental goals, leads to the implementation of specific stream naturalization practices.
A DECISION SUPPORT TOOL FOR THE MANAGEMENT OF MULTI‐RESERVOIR SYSTEMS1
Authors: Koutsoyiannis D. , Efstratiadis A. , Karavokiros G.
Published: June 2007

ABSTRACT: A decision support tool is developed for the management of water resources, focusing on multipurpose reservoir systems. This software tool has been designed in such a way that it can be suitable to hydrosystems with multiple water uses and operating goals, calculating complex multi‐reservoir systems as a whole. The mathematical framework is based on the parameterization‐simulation‐optimization scheme. The main idea consists of a parametric formulation of the operating rules for reservoirs and other projects (i.e., hydropower plants). This methodology enables the radical decrease of the number of decision variables, making feasible the location of the optimal management policy, which maximizes the system yield and the overall operational benefit and minimizes the risk for the management decisions. The program was developed using advanced software engineering techniques. It is adaptable in a wide range of water resources systems, and its purpose is to support water and power supply companies and related authorities. It already has been applied to two of the most complicated hydrosystems of Greece, the first time as a planning tool and the second time as a management tool.
RESERVOIR WATER LEVEL IMPACTS ON RECREATION, PROPERTY, AND NONUSER VALUES1
Authors: Hanson Terrill R. , Hatch Luther Upton , Clonts Howard C.
Published: June 2007

ABSTRACT: Wise interbasin management of Southeastern U.S. water resources is important for future development. Alabama‐Coosa‐Tallapoosa and Apalachicola‐Flint‐Chattahoochee River basins' water usage has evolved from power generation to multiple uses. Recreation and housing have become increasingly valuable components. Changing use patterns imply changing resource values. This study focused on six Alabama reservoirs, using contingent valuation questions in on‐site, telephone, and mail surveys to estimate impacts on lakefront property values, recreational expenditures, and preservation values for scenarios of permanent changes to reservoir water quantity. As summer full‐pool duration decreased, lakefront property value decreased, and as duration increased, property values increased, but at a lesser rate. Similar findings occurred for winter draw down alternatives. Permanent one‐foot reductions in summer full‐pool water levels resulted in a 4 to 15 percent decrease in lakefront property values. Recreational expenditures decreased 4 to 30 percent for each one‐foot lowering of reservoir water levels. Current nonusers of the six reservoirs showed strong preferences for protecting study reservoirs with willingness to pay values of 47 per household or approximately 29 million for the entire six‐reservoir watershed basin area. Resource management based on historic use patterns may be inappropriate and more frequent and comprehensive valuation of reservoir resources is needed.
A LARGE ELECTRONIC WEIGHING LYSIMETER SYSTEM: DESIGN AND INSTALLATION1
Authors: Barani Gholam‐Abbas , Khanjani Mohammad Javad
Published: June 2007

ABSTRACT: To measure crop evapotranspiration, a large double tank, electronic weighting lysimeter system was designed and installed at the Shahid Bahonar University farm, Kerman, Iran. The system was installed in a 50 m2 underground building. It includes two tanks of 3.00 m in diameter and 1.75 m deep. The weighing mechanism for each tank is a set of three compression strain gage load cells, which are fixed on 1.20 m height column above the floor. According to the specification of the load cells, the maximum possible weighing error may be about 0.01 percent of total mass, which is equivalent to 0.28 mm of water, but the measured error was equal to 1 kg mass, which is equivalent to 0.14 mm of water. The load cell data from each tank and the on‐site environmental data (temperature, humidity, and wind velocity and direction) are automatically recorded and saved in a personal computer hard disk for further use and analysis.
IMPLICATIONS OF CLIMATIC VARIABILITY FOR REGULATORY LOW FLOWS IN THE SOUTH PLATTE RIVER BASIN, COLORADO1
Authors: Saunders James F. , Lewis William M.
Published: June 2007

ABSTRACT: The maximum concentration of a regulated substance that is allowed in a wastewater effluent usually is determined from the amount of dilution provided by the receiving water. Dilution flow is estimated from historical data by application of statistical criteria that define low flow conditions for regulatory purposes. Such use of historical data implies that the past is a good indicator of future conditions, at least for the duration of a discharge permit. Short records, however, introduce great uncertainty in the estimation of low flows because they are unlikely to capture events with recurrence frequencies of multiple years (e.g., ENSO events or droughts). We conducted an analysis of daily flows at several gages with long records in the South Platte River basin of Colorado. Low flows were calculated for successive time blocks of data (3‐, 5‐, 10‐, and 20‐years), and these were compared with low flows calculated for the entire period of record (> 70 years). In unregulated streams, time blocks of three or five years produce estimates of low flows that are highly variable and consistently greater than estimates derived from a longer period of record. Estimates of low flow from 10‐year blocks, although more stable, differ from the long term estimates by as much as a factor of two because of climate variation. In addition, the hydrographs of most streams in Colorado have been influenced by dams, diversions, or water transfers. These alterations to the natural flow regime shorten the record that is useful for analysis, but also tend to increase the calculated low flows. The presence of an upward trend in low flows caused by water use represents an unanticipated risk because it fails to incorporate societal response to severe drought conditions. Thus, climate variability poses a significant risk for water quality both directly, because it may not be represented adequately in the short periods of the hydrologic record that are typically used in permits, and indirectly, through its potential to cause altered use of water during time of scarcity.
LIMITATIONS AND IMPLICATIONS OF STREAM CLASSIFICATION1
Authors: Juracek Kyle E. , Fitzpatrick Faith A.
Published: June 2007

ABSTRACT: Stream classifications that are based on channel form, such as the Rosgen Level II classification, are useful tools for the physical description and grouping of streams and for providing a means of communication for stream studies involving scientists and (or) managers with different backgrounds. The Level II classification also is used as a tool to assess stream stability, infer geomorphic processes, predict future geomorphic response, and guide stream restoration or rehabilitation activities. The use of the Level II classification for these additional purposes is evaluated in this paper. Several examples are described to illustrate the limitations and management implications of the Level II classification. Limitations include: (1) time dependence, (2) uncertain applicability across physical environments, (3) difficulty in identification of a true equilibrium condition, (4) potential for incorrect determination of bankfull elevation, and (5) uncertain process significance of classification criteria. Implications of using stream classifications based on channel form, such as Rosgen's, include: (1) acceptance of the limitations, (2) acceptance of the risk of classifying streams incorrectly, and (3) classification results may be used inappropriately. It is concluded that use of the Level II classification for purposes beyond description and communication is not appropriate. Research needs are identified that, if addressed, may help improve the usefulness of the Level II classification.
A MODIFIED RATIONAL FORMULA FOR FLOOD DESIGN IN SMALL BASINS1
Authors: Hua Jiapeng , Liang Zhongmin , Yu Zhongbo
Published: June 2007

ABSTRACT: New formulas and procedures under the framework of the Rational Formula are presented that are applicable to flood design problems for a small basin if the geometry of the basin can be approximated as an ellipse or a rhombus. Instead of making the assumption in the traditional rational formula that the rainfall is uniformly distributed in the whole duration (Dw) of a design storm, the new method modifies that assumption as: the rainfall is uniformly distributed only in each time interval CD) of the design storm hyetograph, thus extending the rational formula applicable to the case that the rainfall duration is less than the basin concentration time (Tc). The new method can be applied to estimate the flood design peak discharge, and to generate the flood hydrograph simultaneously. The derivation of the formulas is provided in detail in this paper, and an example is also included to illustrate how to apply the new formulas to the flood design problems in small basins.
WATER TRANSFERS AND THEIR IMPACTS: LESSONS FROM THREE COLORADO WATER MARKETS1
Authors: Howe Charles W. , Goemans Christopher
Published: June 2007

ABSTRACT: This paper presents an analysis of the effects of different institutional arrangements and economic environments on water markets. Characteristics of water rights transfers in the South Platte Basin of Colorado and transfers of shares of the Northern Colorado Water Conservancy District (NCWCD) are compared to show how different institutional arrangements can affect the types and size distributions of transfers. The characteristics of water rights transfers in the prosperous South Platte are then compared with water rights transfer characteristics in the economically marginal Arkansas River basin of Colorado to identify the effects of different economic environments. Finally, the economic losses from reductions in irrigated acreage resulting from water transfers are estimated for the South Platte and Arkansas and compared with purchase prices by municipalities. Transfers in the South Platte were to new uses in the same basin, while more recent transfers in the Arkansas were to out of basin users. Transfers of South Platte rights and especially NCWCD shares were small and continuous over time, while transfers in the Arkansas were dominated by a few very large transfers. The negative impacts are judged to be more severe in the Arkansas basin than in the South Platte. Purchase prices paid by municipalities substantially exceeded capitalized transitional losses in the selling areas. In the South Platte, gains and losses were in the same basin, while the Arkansas absorbed the losses, with the benefits going to the purchasing basin.
IMPROVED RAINFALL/RUNOFF ESTIMATES USING REMOTELY SENSED SOIL MOISTURE1
Authors: Jacobs Jennifer M. , Myers David A. , Whitfield Brent M.
Published: June 2007

ABSTRACT: Remotely sensed soil moisture data measured during the Southern Great Plains 1997 (SGP97) experiment in Oklahoma were used to characterize antecedent soil moisture conditions for the Soil Conservation Service (SCS) curve number method. The precipitation‐adjusted curve number and the soil moisture were strongly related (r2= 0.70). Remotely sensed soil moisture fields were used to adjust the curve numbers and the runoff estimates for five watersheds, in the Little Washita watershed; the results ranged from 2.8 km2 to 601.6 km2. The soil moisture data were applied at two spatial scales, a finer one (800 m) measuring spatial resolution and a coarser one (28 km). The root mean square error (RMSE) and the mean absolute error (MAE) of the runoff estimated by the standard SCS method was reduced by nearly 50 percent when the 800 m soil moisture data were used to adjust the curve number. The coarser scale soil moisture data also significantly reduced the error in the runoff predictions with 41 percent and 28 percent reductions in MAE and RMSE, respectively. The results suggest that remote sensing of soil moisture, when combined with the SCS method, can improve rainfall runoff predictions at a range of spatial scales.
COLD WATER PATCHES IN WARM STREAMS: PHYSICOCHEMICAL CHARACTERISTICS AND THE INFLUENCE OF SHADING1
Authors: Ebersole Joseph L. , Liss William J. , Frissell Christopher A.
Published: June 2007

ABSTRACT: Discrete cold water patches within the surface waters of summer warm streams afford potential thermal refuge for cold water fishes during periods of heat stress. This analysis focused on reach scale heterogeneity in water temperatures as influenced by local influx of cooler subsurface waters. Using field thermal probes and recording thermistors, we identified and characterized cold water patches (at least 3°C colder than ambient streamflow temperatures) potentially serving as thermal refugia for cold water fishes. Among 37 study sites within alluvial valleys of the Grande Ronde basin in northeastern Oregon, we identified cold water patches associated with side channels, alcoves, lateral seeps, and floodplain spring brooks. These types differed with regard to within floodplain position, area, spatial thermal range, substrate, and availability of cover for fish. Experimental shading cooled daily maximum temperatures of surface waters within cold water patches 2 to 4°C, indicating a strong influence of riparian vegetation on the expression of cold water patch thermal characteristics. Strong vertical temperature gradients associated with heating of surface layers of cold water patches exposed to solar radiation, superimposed upon vertical gradients in dissolved oxygen, can partially restrict suitable refuge volumes for stream salmonids within cold water patches.
A STRATEGY FOR IMPLEMENTING BMPs FOR CONTROLLING NONPOINT SOURCE POLLUTION: THE CASE OF THE FEI‐TSUI RESERVOIR WATERSHED IN TAIWAN1
Authors: Lin Jen‐Yang , Hsieh Cheng‐Daw
Published: June 2007

ABSTRACT: This paper describes a concerted effort by the Taiwan Water Resources Bureau, the City of Taipei, and the Bureau of Fei‐tsui Reservoir Management to protect the water quality in the Fei‐tsui Reservoir.The reservoir is the major source of water supply for over two million people in the metropolitan area of Taipei. Over the years the reservoir has suffered from siltation and more recently eutrophication. The sources of the pollution are traced to the hundreds of tea gardens, rice fields and other agricultural areas in the watershed and to urban sources such as construction sites. Large amounts of nutrients enter the reservoir by way of storm water runoff during storm or typhoon events. Since 1999, various agencies have worked to initiate an effort to reduce nonpoint pollution in the Fei‐Tsui Reservoir watershed. Practices being considered include nonstructural measures such as nutrient management, and structural measures such as swales, detention basins, and wetlands, in addition to erosion and sediment control methods. A number of field tests have been completed on the performance of selected best management practices (BMPs). A strategy for implementing the BMPs at the watershed scale has been developed based on a total maximum daily load (TMDL) analysis that is reported in this paper.
HYDROLOGIC SIMULATION OF THE LITTLE WASHITA RIVER EXPERIMENTAL WATERSHED USING SWAT1
Authors: Van Liew Michael W. , Garbrecht Jurgen
Published: June 2007

ABSTRACT: Precipitation and streamflow data from three nested subwatersheds within the Little Washita River Experimental Watershed (LWREW) in southwestern Oklahoma were used to evaluate the capabilities of the Soil and Water Assessment Tool (SWAT) to predict streamflow under varying climatic conditions. Eight years of precipitation and streamflow data were used to calibrate parameters in the model, and 15 years of data were used for model validation. SWAT was calibrated on the smallest and largest sub‐watersheds for a wetter than average period of record. The model was then validated on a third subwatershed for a range in climatic conditions that included dry, average, and wet periods. Calibration of the model involved a multistep approach. A preliminary calibration was conducted to estimate model parameters so that measured versus simulated yearly and monthly runoff were in agreement for the respective calibration periods. Model parameters were then fine tuned based on a visual inspection of daily hydrographs and flow frequency curves. Calibration on a daily basis resulted in higher baseflows and lower peak runoff rates than were obtained in the preliminary calibration. Test results show that once the model was calibrated for wet climatic conditions, it did a good job in predicting streamflow responses over wet, average, and dry climatic conditions selected for model validation. Monthly coefficients of efficiencies were 0.65, 0.86, and 0.45 for the dry, average, and wet validation periods, respectively. Results of this investigation indicate that once calibrated, SWAT is capable of providing adequate simulations for hydrologic investigations related to the impact of climate variations on water resources of the LWREW.
SIMULATING HYDROLOGIC AND WATER QUALITY IMPACTS IN AN URBANIZING WATERSHED1
Authors: Im Sangjun , Brannan Kevin M. , Mostaghimi Saied
Published: June 2007

ABSTRACT: The Hydrologic Simulation Program‐Fortran (HSPF) was calibrated and used to assess the future effects of various land development scenarios on water quality in the Polecat Creek watershed in Caroline County, Virginia. Model parameters related to hydrology and water quality were calibrated and validated using observed stream flow and water quality data collected at the watershed outlet and the outlets of two sub water sheds. Using the county's Comprehensive Plan, land use scenarios were developed by taking into account the trends and spatial distributions of future development. The simulation results for the various land use scenarios indicate that runoff volume and peak rate increased as urban areas increased. Urbanization also increased sediment loads mainly due to increases in channel erosion. Constituent loads of total Kjeldal nitrogen, orthophosphorus, and total phosphorous for Polecat Creek watershed slightly decreased under future development scenarios. These reductions are due to increases in urban areas that typically contribute smaller quantities of nitrogen and phosphorous, as compared to agricultural areas. However, nitrate loads increased for the future land use scenarios, as compared to the existing land use. The increases in nitrate loads may result from increases in residential land and associated fertilizer use and concurrent decreases in forested land. The procedures used in this paper could assist local, state, and regional policy makers in developing land management strategies that minimize environmental impacts while allowing for future development.
ECOSYSTEM DYNAMICS AND POLLUTION EFFECTS IN AN OZARK CAVE STREAM1
Authors: Graening Gary O. , Brown Arthur V.
Published: June 2007

ABSTRACT: Subterranean ecosystems harbor globally rare fauna and important water resources, but ecological processes are poorly understood and are threatened by anthropogenic stresses. Ecosystem analyses were conducted from 1997 to 2000 in Cave Springs Cave, Arkansas, situated in a region of intensive land use, to determine the degree of habitat degradation and viability of endangered fauna. Organic matter budgeting quantified energy flux and documented the dominant input as dissolved organic matter and not gray bat guano (Myotis grisescens). Carbon/nitrogen stable isotope analyses described a trophic web of Ozark cavefish (Amblyopsis rosae) that primarily consumed cave isopods (Caecidotea stiladactyla), which in turn appeared to consume benthic matter originating from a complex mixture of soil, leaf litter, and anthropogenic wastes. Septic leachate, sewage sludge, and cow manure were suspected to augment the food web and were implicated in environmental degradation. Water, sediment, and animal tissue analyses detected excess nutrients, fecal bacteria, and toxic concentrations of metals. Community assemblage may have been altered: sensitive species‐grotto salamanders (Typhlotriton spelaeus) and stygobro‐mid amphipods—were not detected, while more resilient isopods flourished. Reduction of septic and agricultural waste inputs may be necessary to restore ecosystem dynamics in this cave ecosystem to its former undisturbed condition.
BUILDUP, WASHOFF, AND EVENT MEAN CONCENTRATIONS1
Authors: Butcher Jonathan B.
Published: June 2007

ABSTRACT: Most watershed water quality simulation models require the user to specify pollutant buildup and washoff rate parameters for pollutants, by land use. Buildup and washoff rates are difficult to measure directly, and only limited guidance and few observed data are available from the literature. Many studies, however, report storm event mean concentrations (EMCs). These EMCs must arise as a result of the buildup and washoff processes, but typically represent the net contribution from a variety of pervious and impervious surfaces. This paper explores the relationship between EMCs and buildup/washoff parameters. An assumption of the mathematical form of the buildup/washoff relationship gives an algebraic expression for the EMC consistent with model assumptions. This yields techniques to separate observed EMCs into contributions from different land uses and from pervious and impervious surfaces. Given this relationship, numerical optimization may be used to estimate site specific values of buildup and washoff parameters from observed storm EMCs for use in modeling. Use of this approach helps ensure that model parameters are consistent with observed data, providing a rational starting point for final model calibration. Several site examples demonstrate use of the method.
GEOSTATISTICAL ESTIMATION OF HORIZONTAL HYDRAULIC CONDUCTIVITY FOR THE KIRKWOOD‐COHANSEY AQUIFER1
Authors: Vyas Vikram M. , Tong Saichiu N. , Uchrin Christopher , Georgopoulos Panos G. , Carter Gail P.
Published: June 2007

ABSTRACT: The Kirkwood‐Cohansey aquifer has been identified as a critical source for meeting existing and expected water supply needs for southern New Jersey. Several contaminated sites exist in the region; their impact on the aquifer has to be evaluated using ground water flow and transport models. Ground water modeling depends on availability of measured hydrogeologic data (e.g., hydraulic conductivity, for parameterization of the modeling runs). However, field measurements of such critical data have inadequate spatial density, and their locations are often clustered. The goal of this study was to research, compile, and geocode existing data, then use geostatistics and advanced mapping methods to develop a map of horizontal hydraulic conductivity for the Kirkwood‐Cohansey aquifer. Spatial interpolation of horizontal hydraulic conductivity measurements was performed using the Bayesian Maximum Entropy (BME) Method implemented in the BMELib code library. This involved the integration of actual measurements with soft information on likely ranges of hydraulic conductivity at a given location to obtain estimate maps. The estimation error variance maps provide an insight into the uncertainty associated with the estimates, and indicate areas where more information on hydraulic conductivity is required.
WEPP INTERNET INTERFACES FOR FOREST EROSION PREDICTION1
Authors: Elliot William J.
Published: June 2007

ABSTRACT: The Water Erosion Prediction Project (WEPP) is a physically based erosion model for applications to dryland and irrigated agriculture, rangeland, and forests. U.S. Forest Service (USFS) experience showed that WEPP was not being adapted because of the difficulty in building files describing the input conditions in the existing interfaces. To address this difficulty, a suite of Internet interfaces with a database was developed to more easily predict soil erosion for a wide range of climatic and forest conditions, including roads, fires, and timber harvest. The database included a much larger climate database than was previously available for applications in remote forest and rangeland areas. Validation results showed reasonable agreement between erosion values reported in the literature and values predicted by the interfaces to the WEPP model.
COST EFFECTIVE ARSENIC REDUCTIONS IN PRIVATE WELL WATER IN MAINE1
Authors: Sargent‐Michaud Jessica , Boyle Kevin J. , Smith Andrew E.
Published: June 2007

ABSTRACT: This study was undertaken to investigate the cost effectiveness of selected arsenic avoidance methods. Annual costs of reverse osmosis (RO), activated alumina (AA), bottled water, and rented and purchased water coolers for various household sizes in Maine were compared. Relative ranking of systems shows that RO ($411 annually) is the most cost effective, followed by AA ($518) and one‐gallon jugs of water ($321 to $1,285), respectively, for households larger than one person. One‐gallon jugs ($321) followed by 2.5‐gallon jugs ($358) of water were found to be the most cost effective for households of one person or for households with arsenic III concentrations of 0.02 to 0.06 mg/L and arsenic V concentrations of 0.08 to 1.0 mg/L. Point‐of‐entry systems and water coolers were not found to be cost effective under any of the study's conditions. The research reported here will help states make more definitive treatment recommendations to households regarding the cost effectiveness of alternative treatment systems to reduce arsenic concentrations below 0.01 mg/L. While arsenic removal technologies are improving, which enhances removal rates and reduces costs, the major insights from this analysis appear to be reinforced by technological improvements.
The use of extended dose range film for dosimetric calibration of a scanning liquid‐filled ionization chamber electronic portal imaging device
Authors: Mohammadi Mohammad , Bezak Eva , Reich Paul
Published: June 2007

A scanning liquid‐filled ionization chamber electronic portal imaging device (SLIC‐EPID) and extended dose range (EDR2) films were used to evaluate transmitted dose profiles for homogeneous and inhomogeneous phantoms. Calibrated ionization chamber measurements were used to convert the pixel values acquired from the electronic portal images to dose. Because SLIC‐EPID was developed to have a uniform response for all liquid ionization chambers, the off‐axis dose values were reconstructed using a correction factor matrix, defined as the ratio of the relative EDR2 film and the corresponding EPID dose values measured in air. The transmitted dose distributions in the EPID detector layer were also modeled using a treatment planning system (TPS: Philips Radiation Oncology Systems, Milpitas, CA). The gamma function algorithm was then used to assess agreement between transmitted dose distributions measured using a SLIC‐EPID and EDR2 film, and those calculated using the TPS. For homogenous and inhomogeneous phantoms, more than 90% agreement was achieved using gamma criteria of 2% and 3 mm and 3% and 2.5 mm respectively. Our results indicate that the calibration procedure proposed in the present study should be performed if SLIC‐EPID is to be used as a reliable two‐dimensional transmitted dosimeter for clinical purposes.

PACS numbers: 87.53.Tf, 87.53.Oq
Parallels Between Cytokinesis and Retroviral Budding: A Role for the ESCRT Machinery
Authors: Carlton Jez G. , Martin-Serrano Juan
Published: June 2007

During cytokinesis, as dividing animal cells pull apart into two daughter cells, the final stage, termed abscission, requires breakage of the midbody, a thin membranous stalk connecting the daughter cells. This membrane fission event topologically resembles the budding of viruses, such as HIV-1, from infected cells. We found that two proteins involved in HIV-1 budding—tumor susceptibility gene 101 (Tsg101), a subunit of the endosomal sorting complex required for transport I (ESCRT-I), and Alix, an ESCRT-associated protein—were recruited to the midbody during cytokinesis by interaction with centrosome protein 55 (Cep55), a centrosome and midbody protein essential for abscission. Tsg101, Alix, and possibly other components of ESCRT-I were required for the completion of cytokinesis. Thus, HIV-1 budding and cytokinesis use a similar subset of cellular components to carry out topologically similar membrane fission events.
Nuclease-Resistant Single-Stranded DNA Controls for Nucleic Acid Amplification Assays
Authors: Gotsch Antje , Schubert Andreas , Bombis Armin , Wiedmann Michael , Zauke Michael , Schorling Stefan
Published: June 2007

Molecular diagnostic tests based on the PCR or alternative nucleic acid amplification technologies are commonly used for pathogen screening at blood drawing centers. Contrived process surveillance using test-specific external and internal controls is critical for the efficient leverage of PCR power. We describe here novel control constructs for use in nucleic acid amplification assays for pathogens with a single-stranded DNA genome, e.g., parvovirus B19. These controls are derived from a deletion mutant of the filamentous phage fd-tet, fKN16, and consist of single-stranded DNA packaged in a protein coat. They are essentially noninfectious to
Escherichia coli
and highly resistant to nuclease degradation. fKN16 based controls can be readily manufactured and highly purified. Despite their confirmed filamentous morphology, they can be precisely and accurately diluted over a wide range. Stability studies reveal that the novel control constructs are highly resistant to temperature stress, regardless of whether they are tested as concentrated stocks in storage buffer or diluted in buffer or human plasma. Real-time amplification curves derived from recombinant control constructs containing a parvovirus B19 specific sequence fragment match those derived from native virus. In summary, our data demonstrate the feasibility of novel nuclease-resistant single-stranded DNA controls as surrogates for parvovirus B19 and their applicability in routine molecular diagnostics.