bluuebunny/crossref_metadata_2025 huggingface dataset:
SIMULATING SEDIMENT TRANSPORT IN THE CARSON RIVER AND LAHONTAN RESERVOIR, NEVADA, USA1
Authors: Heim K. J. , Warwick J. J.
Published: June 2007

ABSTRACT: The discovery of the Comstock Lode in western Nevada in 1859 initiated the use of liquid mercury (Hg) or “quicksilver” to remove gold (Au) and silver (Ag) from crushed ore. Today, Hg is present in historic mill tailings piles, in alluvial deposits adjacent to the Carson River, and in Lahontan Reservoir. Mercury concentrations in Carson River water have been reported as high as 61 μg/L by the U.S. Geological Survey. Fish from Lahontan Reservoir have methylmorcury (MeHg) concentrations as much as four times the 1.0 μg/g limit for human consumption. Since more than 95 percent of total Hg in water can be associated with particulates, the transport of sediment must be quantified to understand the fate of Hg in the system. By linking the RIVMOD hydrodynamic model with the WASP5 water quality model, and using suspended sediment rating curves along with bedload transport equations, reliable predictions of sediment transport can be made. Measured suspended sediment data from the Carson River, and an estimate of annual sediment loading to Lahontan Reservoir, were used to create a calibrated sediment transport model. Model simulations predicted the long term transport of sediment into Lahontan Reservoir, the transport of sediment into Lahontan Reservoir during a flood year (1986 water year), and concentrations of total Hg in the Carson River using an estimate of sediment Hg concentrations. This research will eventually be used with an Hg model to predict the fate of Hg in the river and reservoir system.
PROMOTING GROUND WATER POLLUTION PREVENTION IN SMALL BUSINESSES1
Authors: Lowrie Karen W. , Greenberg Michael
Published: June 2007

ABSTRACT: Although they have not been the focus of major regulations, small businesses can contribute pollutants to ground water through routine practices. Because strict regulation of millions of micro firms is not likely, water resource professionals face a challenge of how to reach small business operators with effective pollution prevention messages. The purpose of this study was to examine the factors that influence a small business operator to adopt measures that reduce potential ground water pollution. We looked at how information delivery, internal business characteristics, and external relationships are associated with voluntary preventive measures. Mail surveys from small businesses in New Jersey municipalities and interviews with business owners provided data about business characteristics and current pollution prevention activities. Findings suggested that businesses doing the most to prevent ground water pollution were generally more connected to external organizations and had more financial and technical resources. The study also discovered that small business owners fear government involvement in their affairs. The study concludes with recommendations to encourage more voluntary adoption of prevention measures by businesses. These center on separating assistance programs from enforcement and involving industry peer groups in an effort to make information available in a non‐threatening manner.
TRENDS IN PRECIPITATION AND STREAM CHEMISTRY IN A PRISTINE OLD‐GROWTH FOREST WATERSHED, OLYMPIC NATIONAL PARK, WASHINGTON1
Authors: Edmonds Robert L. , Blew Roger D.
Published: June 2007

ABSTRACT: Human induced long‐term changes in precipitation and stream chemistry have been observed in eastern North America and Europe, but few long‐term studies have been conducted in coastal western North America. The objectives of this research were to determine: (1) time trends in precipitation and stream chemistry in a pristine old‐growth forest watershed, and (2) seasonal patterns in precipitation and stream chemistry. It was conducted in 58 ha West Twin Creek Watershed, Hoh River Valley, Olympic National Park, Washington from 1984 to 1993. Vegetation consists of old‐growth forest, with western hemlock, Douglas‐fir, western redcedar, Pacific silver fir, and Sitka spruce being the dominant tree species. Annual precipitation varied from 2336 to 4518 mm during the study period with the majority of the rain falling between October and May. Chemistry of precipitation was strongly dominated by oceanic influences with Na and Cl being the dominant ions. The chemistry of the stream was influenced by bedrock weathering and was dominated by Ca, HCO3, and SO4 and was not strongly related to precipitation chemistry. The pH of precipitation averaged 5.3 over time and ranged from 4.3 to 7.1, while the stream pH averaged 7.5 and ranged from 5.5 to 9.0. There were few long‐term trends in the chemical constituents of bulk precipitation or stream water with the exception of a slight decrease in NO3 in precipitation and an increase of SO4 in stream water. A trend of decreasing concentrations of Ca, Mg and Na in precipitation also occurred. There were no significant seasonal patterns in precipitation although the highest SO4 concentrations usually occurred in late spring and summer perhaps due marine algal activity. Strong seasonal trends occurred in concentrations of HCO3, SO4, Ca, Mg, and Na in stream water resulting from weathering and stream flow patterns, with highest ion concentrations occurring just before the onset of the rainy season. Pulses of NO3 in the stream were observed during fall and early winter resulting from the release of NO3 which had accumulated in soils or sediments.
A WATERSHED APPROACH TO ECOSYSTEM MONITORING IN DENALI NATIONAL PARK AND PRESERVE, ALASKA1
Authors: Thorsteinson Lyman K. , Taylor Dale L.
Published: June 2007

ABSTRACT: The National Park Service and the National Biological Service initiated research in Denali National Park and Preserve, a 2.4 million‐hectare park in southcentral Alaska, to develop ecological monitoring protocols for national parks in the Arctic/Subarctic biogeographic area. We are focusing pilot studies on design questions, on scaling issues and regionalization, ecosystem structure and function, indicator selection and evaluation, and monitoring technologies. Rock Creek, a headwater stream near Denali headquarters, is the ecological scale for initial testing of a watershed ecosystem approach. Our conceptual model embraces principles of the hydrological cycle, hypotheses of global climate change, and biological interactions of organisms occupying intermediate, but poorly studied, positions in Alaskan food webs. The field approach includes hydrological and depositional considerations and a suite of integrated measures linking key aquatic and terrestrial biota, environmental variables, or defined ecological processes, in order to establish ecological conditions and detect, track, and understand mechanisms of environmental change. Our sampling activities include corresponding measures of physical, chemical, and biological attributes in four Rock Creek habitats believed characteristic of the greater system diversity of Denali. This paper gives examples of data sets, program integration and scaling, and research needs.
STREAM CHANNEL ADJUSTMENTS FOLLOWING ELIMINATION OF CAVFLE GRAZING1
Authors: Magilligan Francis J. , McDowell Patricia F.
Published: June 2007

ABSTRACT: Cattle grazing practices in the western United States have contributed to widespread riparian degradation resulting in unstable channel morphologies and the loss of fish habitat. Because of prolonged disturbance, numerous riparian areas on both public and private lands have been fenced to exclude cattle in order to promote vegetation establishment and riparian improvement. We selected four gravel‐bedded, steep alluvial streams in eastern Oregon with cattle exclosures greater than 14 years old for an analysis of geomorphic adjustments following the removal of cattle grazing. We compare channels inside exclosures and in adjacent grazed reaches to identify the salient stream channel properties that respond to the removal of riparian stresses and to document the magnitude of these changes. Results indicate that significant changes occur, with reductions in bankfull dimensions and increases in pool area being the most common and identifiable changes. At all four sites, bankfull widths are narrower by 10 to 20 percent, and the percentage of channel area occupied by pools is higher in the exclosure by 8 to 15 percent. The increase in pool area is primarily offset by a reduction in the percent glide area. Not all of the channel properties demonstrate adjustment, indicating that perhaps 14 years is an insufficient duration for these variables to adjust.
PREDICTIVE MODEL FOR NITRATE LOAD IN THE BULL RUN WATERSHED, OREGON1
Authors: Bakke Paul D. , Pyles Marvin R.
Published: June 2007

ABSTRACT:Predictive models for nitrate in four streams in the Bull Run Watershed in the Cascade Mountains of Oregon were developed from a record of 17 years of nitrate samples. The models are time series regression models written in terms of Log(nitrate load). The independent variables are logarithm of 14‐day mean daily stream discharge, current day's precipitation, logarithm of the previous day's precipitation, total precipitation for the previous seven days, a hydrograph position variable that indicates rising or falling limb, and average maximum air temperature for the preceding 14 days. The models describe annual cycle and seasonable trends and variations in nitrate load, but are unable to describe large day to day variations like those associated with hydrograph peaks.
IMPACT OF COAL SURFACE MINING ON THREE OHIO WATERSHEDS ‐ SURFACE‐WATER HYDROLOGY1
Authors: Bonta J. V. , Amerman C. R. , Harlukowicz T. J. , Dick W. A.
Published: June 2007

ABSTRACT: A study was conducted to determine the effects of mining and reclaiming originally undisturbed watersheds on surface‐water hydrology in three small experimental watersheds in Ohio. Approximately six years of data were collected at each site, with differing lengths of premining (Phase 1), mining and reclamation (Phase 2), and post‐reclamation (Phase 3) periods. Mining and reclamation activities showed no consistent pattern iii base‐flow, and caused slightly more frequent higher daily flow volumes. Phase 2 activities can cause reductions in seasonal variation in double mass curves compared with Phase 1. Restoration of seasonal variations was noticeably apparent at one site during Phase 3. The responses of the watersheds to rainfall intensities causing larger peak flow rates generally decreased due to mining and reclamation, but tended to exceed responses observed in Phase 1 during Phase 3. Natural Resources Conservation Service (NRCS) curve numbers increased due to mining and reclamation (Phase 2), ranging from 83 to 91. During Phase 3, curve numbers remained approximately constant from Phase 2, ranging from 87 to 91.
PUMP SYSTEM FOR IMPROVING RUNOFF RECORDS DURING WINTER1
Authors: Bonta James V
Published: June 2007

ABSTRACT: Freezing winter temperatures can cause icing of outdoor weirs used to measure surface runoff. Ice typically forms in the notch and on the crests of short‐crested V‐notch weirs, causing incorrect gage heights to be measured. A method for reducing the effects of ice formation on weirs and weir pools using a pump is presented and evaluated. Warmer water from the bottom of the weir pool is pumped to the surface, reducing the opportunity for the water surface to freeze. The pump is shown to work except under extremely cold conditions, improving runoff records from 27 percent to 60 percent. The pump system has no practical effect on measured gage height. Frequency distributions of flow rates and air temperatures under measured ice‐free and other weir conditions are presented. Suggestions for use of the pump system under temperature conditions other than those in this study are given.
ELEVATED ATMOSPHERIC CO2 INCREASES WATER AVAILABILITY IN A WATER‐LIMITED GRASSLAND ECOSYSTEM1
Authors: Fredeen Arthur L. , Randerson James T. , Holbrook N. Michele , Field Christopher B.
Published: June 2007

ABSTRACT: Californian annual grassland on sandstone (moderately fertile) and serpentine (very infertile) soils at the Jasper Ridge Biological Preserve, Stanford, California, were exposed to ambient or elevated (ambient + 36 Pa CO2) atmospheric CO2 in open‐top chambers since December 1991. We measured ecosystem evapotranspiration with open gas‐exchange systems, and soil moisture with time‐domain reflectometry (TDR) over 0–15 cm (serpentine) and 0–30 cm (sandstone) depths, at times of peak above ground physiological activity. Evapotranspiration decreased by 12 to 63 percent under elevated CO2 in three consecutive years in the sandstone ecosystem (p = 0.053, p = 0.162, p = 0.082 in 1992, 1993, and 1994, respectively). In correspondence with decreased evapotranspiration, late‐season soil moisture reserves in the sandstone were extended temporally by 10 ± 3 days in 1993 and by 28 ± 11 days in 1994. The effect of elevated CO2 on soil moisture was greater in the drier spring of 1994 (419 mm annual rainfall) than in 1993 (905 mm annual rainfall). In the serpentine ecosystem, evapotranspiration and soil moisture reserves were not clearly affected by elevated CO2. Soil water may be conserved in drought‐affected ecosystems exposed to elevated CO2, but the amount of conservation appears to depend on the relative importance of transpiration and soil evaporation in controlling water flux.
CHARACTERIZING GROUND WATER FLOW IN THE MUNICIPAL WELL FIELDS OF CEDAR RAPIDS, IOWA, WITH SELECTED ENVIRONMENTAL TRACERS1
Authors: Boyd Robert A.
Published: June 2007

ABSTRACT: Cedar Rapids obtains its municipal water supply from a shallow alluvial aquifer along the Cedar River in east‐central Iowa. Water samples were collected and analyzed for selected isotopes and chlorofluorocarbons to characterize the ground‐water flow system near the municipal well fields. Analyses of deuterium and oxygen‐18 indicate that water in the alluvial aquifer and in the underlying carbonate bedrock aquifer was recharged from precipitation during modern climatic conditions. Analyses of tritium indicate modern, post‐1952, water in the alluvial aquifer and older, pre‐1952, water in the bedrock aquifer. Mixing of the modern and older waters occurs in areas where (1) the confining layer between the two aquifers is discontinuous, (2) the bedrock aquifer is fractured, or (3) pumping of supply wells induces the flow of water between aquifers. Analyses of chlorofluorocarbons were used to determine the date of recharge of water samples. Water in the bedrock aquifer likely was recharged prior to the 1950s. Water in the alluvial aquifer likely was recharged from the 1960s to 1990s. Biodegradation or sorption probably affected some of the ground water analyzed for chlorofluorocarbons. These processes reduce the concentrations of CFCs, which results in older than actual calculated dates of recharge.
EVALUATING THE ACCURACY OF RAINFALL CATCH BY THREE DIFFERENT GAGES1
Authors: Chang Mingtah , Flanneiy Lee A.
Published: June 2007

ABSTRACT: A U.S. standard gage, a weighing‐type recording gage, a standard gage fitted with an Alter windshield, and a pit gage were installed to evaluate the accuracy and wind effects on rainfall catch. The study was conducted at the Stephen F. Austin Experimental Forest, about 20 km SW of Nacogdoches, Texas. A recording anemometer was also installed at a height corresponding to the standard gage orifice. Based on data from 67 storms collected over a one‐year period (July 1995‐August 1996), all three conventional gages consistently caught less rainfall than the reference pit gage with an average percent deficiency greater than 10 percent. However, the recording gage caught 2.7 percent less and the shielded gage caught 1 percent more than the standard gage—differences less than those reported elsewhere. The deficiencies were highly correlated with storm intensity, duration, or total rainfall. When the correction for wind effect on angle of raindrop inclination is included, the percent catch deficiency of the standard gage was reduced from 11 percent to 6 percent. The remaining errors may be attributed to wind effects (streamline vs. turbulent flow), nonrandom errors, or other unknown sources.
AN ECONOMIC EVALUATION OF TWO WATERSHED MANAGEMENT PRACTICES IN TAIWAN1
Authors: Wang Hurng‐Jyuhn , Hu Su‐Cherng , Kao Chieh‐Chich
Published: June 2007

ABSTRACT: The main purpose of this study is to evaluate the management practice effects on Ming‐Hu and Ming‐Tan reservoir watersheds during the past 15 years. It is difficult to economically evaluate a watershed project consisting of a number of multisectoral and long term management practices and regulations. However, the reservoirs’ hydropower operations and their associated benefits and costs are highlighted in this study. The estimated management practice value (net present value) of 351 million NT (New Taiwan) dollars and a benefit‐cost ratio of 1.189 are obtained for the Ming‐Hu subwatershed. Because the Ming‐Tan hydropower station only began commercial operation in 1992 the estimated management practice value is negative 103 million NT dollars (net present value) and the benefit‐cost ratio is 0.653 in the Ming‐Tan subwatershed. If the analysis period is contained to the year 2010, the benefit‐cost ratio of Ming‐Tan reservoir subwatershed becomes 1.103. Ming‐Hu and Ming‐Tan subwatersheds together share the benefit‐cost ratio of 1.182 and the net present value of 1,589 million NT dollars. The results of the analyses indicate that the Taiwan Power Company, the watershed management agency, has implemented economically efficient watershed practices and regulations in Ming‐Hu and Ming‐Tan reservoir watersheds and the watershed management practices are worthwhile and should be sustained.
CHANNEL CHANGES DOWNSTREAM FROM A DAM1
Authors: Hadley Richard F. , Emmett William W.
Published: June 2007

ABSTRACT: 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 rime 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.
FOREST HYDROLOGY IN THE PACIFIC NORTHWEST: ADDITIONAL RESEARCH NEEDS1
Authors: Beschta Robert L.
Published: June 2007

ABSTRACT: While much is known about the hydrology of forested mountain catchments in the Pacific Northwest, important research questions remain. For example, the dynamics of storm precipitation amounts and the modeling of catchment outflows represent a continuing research need. Without an improved understanding of the spatial and temporal aspects of storm precipitation patterns, our ability to evaluate and improve physically‐based hydrologic models is limited. From a practical perspective, tens of thousands of kilometers of access roads have been constructed across forested catchments of the Pacific Northwest. Yet, few forestry research programs focus on road drainage (e.g., ditches, culverts, fords). The few studies that address this issue indicate road drainage systems need to function effectively over a wide range of flow events and terrain conditions. In addition, historical forest practices associated with hillslopes and riparian systems have altered the character of many Pacific Northwest aquatic ecosystems. If restoration of these systems is to be effective, research efforts are needed to better understand the linkages between riparian forests, geomorphic processes, and hydrologic disturbance regimes.
COST COMPARISON BETWEEN CESSPOOL AND SANITARY SEWERAGE SYSTEMS IN SAUDI URBAN AREAS1
Authors: Abu‐Rizaiza Omar S. , Hammadur Rahman
Published: June 2007

ABSTRACT: Extensive use is made of on‐site wastewater disposal systems of cesspools due to the absence of a sanitary sewerage system in Saudi urban areas. This system has caused the groundwater table to rise to a public nuisance level. A health risk has also evolved. There are several infrastructural, environmental, and social impacts from this, resulting in great financial losses. Examples are: surface water flooding, damage to foundations of buildings and asphalt street pavements, flooded basements and added construction costs required for excavation, dewatering, insulation materials, and special cements. Most of these costs are indirectly being paid by the private and public sectors. This study compares the estimated costs of damage and losses with the estimated costs of building, operating, and maintaining sanitary sewerage systems in the cesspool‐served areas. The annual cost of the cesspool system, depending on the severity of the adverse impacts, ranges from 2.2 to 4.4 times the annual cost of the sanitary sewerage system. Remedies for these impacts are very expensive, and delays in the implementation of the sanitary sewerage facility will make the damage recovery more expensive, and in some cases, impossible. Thus, it is recommended that highest priority to be given to the sanitary sewerage systems in Saudi urban areas.
RUNOFF RESPONSE FROM TWO RECLAIMED WATERSHEDS1
Authors: Harms T. E. , Chanasyk D. S.
Published: June 2007

ABSTRACT: Detailed studies of the surface hydrology of reclaimed surface‐mined watersheds for both rainfall and snowmelt events are non‐existent for central Alberta yet this information is crucial for design of runoff conveyance and storage structures. A study was initiated in 1992 with principal objectives of quantifying surface runoff for both summer rainfall and spring snowmelt events and identifying the dominant flow processes occurring in two reclaimed watersheds. Snowmelt accounted for 86 and 100% of annual watershed runoff in 1993 and 1994, respectively. The highest instantaneous peak flow was recorded during a summer rainfall event with a return period of greater than 50 years. Infiltration‐excess overland flow was identified as the dominant flow process occurring within the Sandy Subsoil Watershed, whereas saturation overland flow was the principal runoff process occurring within the West Watershed.
NONPARAMETRIC TEST PERFORMANCE FOR TRENDS IN WATER QUALITY WITH SAMPLING DESIGN APPLICATIONS1
Authors: Thas O. , Vooren L. Van , Ottoy J. P.
Published: June 2007

ABSTRACT: In this paper four nonparametric tests for monotonic trend detection are compared with respect to their power and accuracy. The importance of comparing powers at equal empirical significance levels rather than nominal levels is stressed. Therefore, an appropriate graphical method is presented. The effect of the sampling frequency is also assessed using Monte Carlo simulations and a trajectory representation that visualizes the dynamics of the trade‐off between the type I and type II errors. These methods are applied to compare four nonparametrical tests (seasonal Mann. Kendall, modified seasonal Mann‐Kendall, covariance eigenvalue and covariance inversion) under several conditions. It is concluded with respect to the power that it is not worthwhile for the modified seasonal Mann‐Kendall test applied to the AR(1) process considered in this paper to increase the sampling frequency from monthly to biweekly for detecting a monotonic trend of 5 percent, 10 percent, or 15 percent of the process variance. Under these conditions the seasonal Mann‐Kendall test is highly liberal, while the covariance inversion and the covariance eigenvalue test are conservative. This research is situated in the development of an efficient sampling design for the Flemish water quality monitoring network.
STRATEGIES FOR SEPARATING METALS FROM ACID MINE WATERS1
Authors: Cheney Marcos A. , Swinehart James H.
Published: June 2007

ABSTRACT: Strategies for the precipitation and separation of the primary metal ions, Fe(II), Cu(II), Zn(II), Mn(II), and Cd(II) in acid waste waters such as those in tributaries of the upper Sacramento River in northern California, are discussed. The strategies exploit the: (1) differential oxygen and hydrogen peroxide oxidation and precipitation properties of the metal ions as a function of pH, (2) the addition of ions, such as Mg2 + and Cl‐, to reduce unfavorable coprecipitation, and (3) the facilitation of oxidation‐reduction reactions between metal ions and the stabilization of particular oxidation states. This may be accomplished with specific complexing agents such as thiocyanate, SCN‐, and thiourea (TU), S = C(NH2)2 in order to separate copper at low pH as Cu(I) using Fe(II) as a reducing agent.
CHARACTERIZATION OF TOXIC CONDITIONS ABOVE WILSON'S CREEK NATIONAL BATTLEFIELD PARK, MISSOUR1
Authors: Pulley Trudy Steidl , Nimmo Del Wayne R. , Tessari John D.
Published: June 2007

ABSTRACT: Wilson's Creek has an extensive history of toxicity from both point and nonpoint sources. Seven‐day chronic daphnid (Ceriodaphnia dubia) bioassays identified one toxic site in the Wilson's Creek watershed. Procedures for the characterization phase of a Toxicity Identification Evaluation (TIE) were modified for chronic assessment and performed on four water samples from the toxic site. The characterization involved chemical/physical alterations of samples, combined with bioassays, to help in identification of the class(es) of toxicants; followed by chemical analyses. To help understand the additivity of mixtures, toxic units were derived. Successive samples contained concentrations of copper, cadmium, nickel and zinc that literature values describe as being chronically toxic to daphnids. Summed chronic toxic units for these values greatly exceeded ambient toxic units, and more than accounted for observed toxicity.

Substantial fluctuations in water quality occurred over the five sampling periods of the characterization studies and a Test of Methods, June through August, 1991. This variability illustrates the difficulty in detecting and documenting nonpoint sources of pollution. Tests using living organisms, in conjunction with toxicity identification methods, on samples taken over time appear to be appropriate for detecting acute and chronic toxicity in areas impacted by intermittent point and nonpoint‐source toxicity.
MODELING TIDAL HYDRODYNAMICS OF SAN DIEGO BAY, CALIFORNIA1
Authors: Wang P. F. , Cheng Ralph T. , Richter Kenneth , Gross E. S. , Sutton Don , Gartner Jeffrey W.
Published: June 2007

ABSTRACT: In 1983, current data were collected by the National Oceanic and Atmospheric Administration using mechanical current meters. During 1992 through 1996, acoustic Doppler current profilers as well as mechanical current meters and tide gauges were used. These measurements not only document tides and tidal currents in San Diego Bay, but also provide independent data sets for model calibration and verification. A high resolution (100‐m grid), depth‐averaged, numerical hydrodynamic model has been implemented for San Diego Bay to describe essential tidal hydrodynamic processes in the bay. The model is calibrated using the 1983 data set and verified using the more recent 1992–1996 data. Discrepancies between model predictions and field data in both model calibration and verification are on the order of the magnitude of uncertainties in the field data. The calibrated and verified numerical model has been used to quantify residence time and dilution and flushing of contaminant effluent into San Diego Bay. Furthermore, the numerical model has become an important research tool in ongoing hydrodynamic and water quality studies and in guiding future field data collection programs.
EFFECT OF WOODY DEBRIS ENTRAPMENT ON FLOW RESISTANCE1
Authors: Dudley Syndi J. , Fischenich J. Craig , Abt Steven R.
Published: June 2007

ABSTRACT: Recent environmental concerns in floodplain management have stimulated research of the effect vegetation and debris have on flow conveyance, and their function in a productive riparian ecosystem. Although the effect of stable, in‐channel woody debris formations on flow resistance has been noted by several authors, studies concerning entrapment of detrital debris in vegetation are lacking. Logs, limbs, branches, leaves and other debris transported during flooding often become lodged against bridges, hydraulic structures, trees and vegetation, and other obstacles, particularly in and near the overbank areas. Hydraulic measurements obtained in a channel prior to and following the removal of woody debris indicated that the average Manning's n value was 39 percent greater when woody debris was present. An examination of the drag‐velocity relation for vegetation indicated that an increase in the frontal area of debris and/or vegetation results in a nearly proportional increase in Manning's n. The influence of debris on flow resistance decreased as flow depth increased.
ANALYSIS OF NITROGEN MANAGEMENT STRATEGIES USING EPIC1
Authors: Ramanarayanan Tharacad S. , Storm Daniel E. , Smolen Michael D.
Published: June 2007

ABSTRACT: This paper illustrates a method of using a hydrologic/water quality model to analyze alternative management practices and recommend best management practices (BMPs) to reduce nitrate‐nitrogen (NO3‐‐N) leaching losses. The study area for this research is Tipton, an agriculturally intensive area in southwest Oklahoma. We used Erosion Productivity Impact Calculator (EPIC), a field‐scale hydrologic/water quality model, to analyze alternative agricultural management practices. The model was first validated using observed data from a cotton demonstration experiment conducted in the Tipton area. Following that, EPIC was used to simulate fertilizer response curves for cotton and wheat crops under irrigated and dryland conditions. From the fertilizer response functions (N‐uptake and N‐leaching), we established an optimum fertilizer application rate for each crop. Individual crop performances were then simulated at optimum fertilizer application rates and crop rotations for the Tipton area, which were selected based on three criteria: (a) minimum amount of NO3‐‐N leached, (b) minimum concentration of NO3‐‐N leached, and (c) maximum utilization of NO3‐‐M. Further we illustrate that by considering residual N from alfalfa as a credit to the following crop and crediting NO3‐‐N present in the irrigation water, it is possible to reduce further NO3‐‐N loss without affecting crop yield.
NORMALIZED UNIT HYDROGRAPH AGGREGATION1
Authors: Tomic' Saša , Burian Steven J.
Published: June 2007

ABSTRACT: The unit hydrograph is a common tool in hydraulic design. Used correctly, it allows a design engineer to estimate a runoff hydrograph from a drainage basin given a rainfall event. The typical method for estimating a unit hydrograph for a gaged watershed is by deconvolution. However, distinct storms produce different unit hydrographs for a single watershed. Consequently, a design engineer usually develops a composite, or average, unit hydrograph based on several recorded storm events. Common methods for estimating this composite unit hydrograph include curve fitting, simple aggregation, and multistorm optimization techniques. This paper introduces a new method to perform aggregation of unit hydrographs. The method is an extension to the simple averaging technique, in which prior to averaging, the individual unit hydrograph time ordinates are normalized with respect to the average time to peak. The normalization method is compared to a simple averaging technique and two multistorm aggregation techniques at six rural watersheds in Alabama. The results indicate that on average the normalization method predicts runoff nearly as accurately as the multistorm techniques, and displays improvement for 60 percent of the storms tested when compared with the simple averaging technique.
AGRICULTURAL NITRATE CONTAMINATION OF GROUND WATER: AN EVALUATION OF ENVIRONMENTAL POLICY1
Authors: Livingston M. L. , Gory D. C.
Published: June 2007

ABSTRACT: The contribution of agriculture to nitrate pollution of 8Urface and ground water is a growing concern throughout the world. The objective of this article is to evaluate the current environmental policy governing nitrate contamination of ground water in the South Platte alluvial aquifer. In particular, the “best management practice” approach is assessed in its relationship to optimal policy design. First, the current physical environmental problem and existing institutional arrangements are described. Second, legal and economic criteria are brought to bear on the question of appropriate policy design. Finally, the strengths and weaknesses of the existing policy are evaluated in this context and changes in policy that would increase effectiveness are recommended. Considerable justification is found for state‐initiated control because victims of ground water pollution are dispersed and risk assessment is technically demanding. However, ex post elements of existing policy must be improved, perhaps through targeting and some devolution in monitoring and enforcement responsibilities.
NONLINEAR MODELING AND PREDICTION OF A RIVER FLOW SYSTEM1
Authors: Tabrizi M. H. N. , Said S. E. , Badr A. W. , Mashor Y , Billings S. A.
Published: June 2007

ABSTRACT: Model estimation and prediction of a river flow system are investigated using nonlinear system identification techniques. We demonstrate how the dynamics of the system, rainfall, and river flow can be modeled using NARMAX (Nonlinear Autoregressive Moving Average with eXogenuous input) models. The parameters of the model are estimated using an orthogonal least squares algorithm with intelligent structure detection. The identification of the nonlinear model is described to represent the relationship between local rainfall and river flow at Enoree station (inputs) and river flow at Whitmire (output) for a river flow system in South Carolina.
APPLICATIONS OF FUZZY LOGIC IN THE DESIGN OF VEGETATED WATERWAYS UNDER UNCERTAINTY1
Authors: Perret J. S. , Prasher S. O.
Published: June 2007

ABSTRACT: Two methods for analyzing uncertainty are described and compared in terms of their applicability for designing vegetated waterways. The first approach uses First and Second Order Analysis and the second employs Fuzzy Logic. The two methods were used to evaluate the uncertain parameters in the Manning formula, which is used for calculating the velocity of water flow in vegetated channels. Results indicate that both approaches can provide the designer with an indication of reliability of the estimates, a way of selecting a design option which meets a specified probability of success, as well as a means of comparing the relative importance of uncertainty in various input parameters. Also, the two methods have the common advantage of being simple and requiring less data about the uncertain parameters compared to the more comprehensive stochastic approaches. Although the Fuzzy Logic approach appears to provide a more conservative design because of its slightly higher variance, compared with the First and Second Order Analysis, both methods have proven to be reliable and suitable to deal with uncertainty.
ANALYSIS OF LAKE‐BOTTOM SEDIMENT TO ESTIMATE HISTORICAL NONPOINT‐SOURCE PHOSPHORUS LOADS1
Authors: Juracek Kyle E.
Published: June 2007

ABSTRACT Bottom sediment in Hillsdale Lake, Kansas, was analyzed to estimate the annual load of total phosphorus deposited in the lake from nonpoint sources. Topographic, bathymetric, and sediment‐core data were used to estimate the total mass of phosphorus in the lake‐bottom sediment. Available streamflow and water‐quality data were used to compute the mean annual mass of phosphorus (dissolved plus suspended) exiting the lake. The mean annual load of phosphorus added to the lake from point sources was estimated from previous studies. A simple mass balance then was used to compute the mean annual load of phosphorus from non‐point sources. The total mass of phosphorus in the lake‐bottom sediment was estimated to be 924,000 kg, with a mean annual load of 62,000 kg. The mean annual mass of phosphorus exiting in the lake outflow was estimated to be about 8,000 kg. The mean annual loads of phosphorus added to the lake from point and nonpoint sources were estimated to be 5,000 and 65,000 kg, respectively. Thus, the contribution to the total mean annual phosphorus load in Hillsdale Lake is about 7 percent from point sources and about 93 percent from nonpoint sources.
RELATIONSHIPS BETWEEN LAND USES AND RAINWATER QUALITY IN A SOUTHCENTRAL PENNSYLVANIA WATERSHED1
Authors: Shertzer Richard H. , Hall David W. , Steffy Scott A. , Kime Rodney A.
Published: June 2007

ABSTRACT: Spatial and temporal variability in rainfall concentrations of nutrients, major ions, and herbicides was monitored at 7 locations in or near the Conodoguinet Creek watershed in south‐central Pennsylvania from 1991.1993. Results were used to (1) compare precipitation quality in forested, agricultural and urban areas, and (2) assess the practicality of using volunteer citizen monitoring in such a study.

As indicated in previous studies, sulfate and nitrogen concentrations in precipitation were linked to sample pH. Concentrations of major ions in precipitation appeared to relate more to regional influences rather than local influences. However, concentrations of herbicides in precipitation may have been influenced by both regional and local use which caused compounds like atrazine, deethylatrazine, propazine, simazine, metolachior, alachlor, ametryn, and prometon to be present in detectable concentrations in rainfall.

Seasonality was evident in nitrogen, sulfate, pH, and herbicide data and was suggested in calcium, iron, manganese, magnesium, orthophosphate, and chloride data. Agricultural weed control activities were probably responsible for the seasonal pattern in pesticide data which peaked in May and June. Tropical storm Danielle may have caused the apparent seasonal patterns for the other nine parameters. This storm did not follow the typical west to east movement pattern and consequently produced rainfall of relative high quality.

A variety of quality assurance checks indicated that trained volunteer citizen monitors were successful participants in this intensive and extensive scientific study, collecting good quality samples in a timely manner. Without this kind of volunteer help, it is extremely difficult to complete studies that require sampling in response to natural events such as rainfall.
EFFECTS OF IMPROVED PRECIPITATION ESTIMATES ON AUTOMATED RUNOFF MAPPING: EASTERN UNITED STATES1
Authors: Bishop Gary D. , Church M. Robbins , Daly Christopher
Published: June 2007

ABSTRACT: We evaluated maps of runoff created by means of two automated procedures. We implemented each procedure using precipitation estimates of both 5‐km and 10‐km resolution from PRISM (Parameter‐elevation Regressions on Independent Slopes Model). Our goal was to determine if using the 5‐km PRISM estimates would improve map accuracy. Visual inspection showed good general agreement among our runoff maps, as well as between our maps and one produced using a manual method. A quantitative uncertainty analysis comparing runoff interpolated from our maps with gage data that had been withheld showed slightly smaller actual and percentage interpolation errors for the 5‐km PRISM‐based maps. Our analyses suggest a modest region‐wide improvement in runoff map accuracy with the use of PRISM‐based precipitation estimates of 5‐km (compared to 10‐km) resolution.
THE WESTERN WATER COMMISSION: WATERSHED MANAGEMENT RECEIVES THE AVI'ENTION OF A NEW GENERATION1
Authors: Fort Denise D.
Published: June 2007

ABSTRACT: Our nation periodically reviews national water policy and considers its directions for the future. The most recent examination was directed at the western United States and the role of the federal agencies in meeting its needs. The West is no longer the frontier, but rather contains vibrant cities and booming centers of international trade, as well as tourism, mineral, and oil and gas development, agricultural, and other development. In this changing environment, federal water policies need to consider the long term sustainability of the West, provide justice to Indian tribes, protect the rivers and ecosystems on which natural systems depend, balance the needs of newcomers with those of agricultural users and communities, and meet a myriad of other demands. The Western Water Policy Review Advisory Commission has just concluded its review of these issues and issued its report. Key among the recommendations is the need to coordinate federal agencies at the basin and watershed level and make government more responsive to local needs, but within a framework that includes national mandates. The Commission's recommendations are presented here, along with some of the issues that surrounded the operations of the Commission.
MODELING DEVELOPED COASTAL WATERSHEDS WITH THE AGRICULTURAL NON‐POINT SOURCE MODEL1
Authors: Choi Kyoung Sik , Blood Elizabeth
Published: June 2007

ABSTRACT: Many coastal states are facing increasing urban growth along their coast lines. The growth has caused urban non‐point source nitrogen runoff to be a major contributor to coastal and estuarine enrichment. Water resource managers are responsible for evaluating the impacts from point and non‐point sources in developed watersheds and developing strategies to manage future growth. Non‐point source models provide an effective approach to these management challenges. The Agricultural Non‐Point Source Model (AGNPS) permits the incorporation of important spatial information (soils, landuse, topography, hydrology) in simulating surface hydrology and nitrogen non‐point source runoff. The AGNPS model was adapted for developed coastal watersheds by deriving urban coefficients that reflect urban landuse classes and the amount of impervious surface area. Popperdam Creek watershed was used for model parameter development and model calibration. Four additional watersheds were simulated to validate the model. The model predictions of the peak flow and total nitrogen concentrations were close to the field measurements for the five sub‐basins simulated. Measured peak flow varied by 30 fold among the sub‐basins. The average simulated peak flow was within 14 percent of the average measured peak flow. Measured total nitrogen loads varied over an order of magnitude among the sub‐basins yet error between the measured and simulated loads for a given sub‐basin averaged 5 percent. The AGNPS model provided better estimates of nitrogen loads than widely used regression methods. The spatial distribution of important watershed characteristics influenced the impacts of urban landuse and projecting future residential expansion on runoff, sediment and nitrogen yields. The AGNPS model provides a useful tool to incorporate these characteristics, evaluate their importance, and evaluate fieldscale to watershed‐scale urban impacts.
PARAMETER UNCERTAINTY IN RAINFALL‐RUNOFF MODELING FOR POLDER SYSTEM DESIGN1
Authors: Yulianti J. S. , Lence Barbara J.
Published: June 2007

ABSTRACT: An approach is developed for incorporating the uncertainty of parameters for estimating runoff in the design of polder systems in ungaged watersheds. Monte Carlo Simulation is used to derive a set of realizations of streamflow hydrographs for a given design rainstorm using the U. S. Soil Conservation Service (SCS) unit hydrograph model. The inverse of the SCS curve number, which is a function of the antecedent runoff condition in the SCS model, is the random input in the Monte Carlo Simulation. Monte Carlo realizations of streamfiow hydrographs are used to simulate the performance of a polder flood protection system. From this simulation the probability of occurrence of flood levels for a particular hydraulic design may be used to evaluate its effectiveness. This approach is demonstrated for the Pluit Polder flood protection system for the City of Jakarta, Indonesia. While the results of the application indicate that uncertainty in the antecedent runoff condition is important, the effects of uncertainty in rainfall data, in additional runoff parameters, such as time to peak, in the hydraulic design, and in the rainfall‐runoff model selected should also be considered. Although, the SCS model is limited to agricultural conditions, the approach presented herein may be applied to other flood control systems if appropriate storm runoff models are selected.
HISTORICAL AND SOCIOPOLITICAL CONTEXT OF THE WESTERN WATERSHEDS MOVEMENT1
Authors: Kenney Douglas S.
Published: June 2007

ABSTRACT: The 1990s have featured a rapid proliferation of “watershed initiatives” in the western United States and elsewhere. Watershed initiatives are ad hoc, voluntary associations typically featuring both governmental and non‐governmental actors organized together to collaboratively seek new strategies for addressing water and related natural resource problems at physically relevant regional scales. These efforts are a response to historical and sociopolitical trends that have resulted in increasingly ineffective forums and processes of resource management decision‐making, and that have subordinated the role of local stakeholders in problem‐solving efforts. In most cases, watershed initiatives appear to provide a pragmatic vehicle for resource managers and stakeholders to address common concerns in a more efficient manner than is otherwise possible, and as such, deserve further application and continued support.
INTEGRATED WATERSHED MANAGEMENT ON THE TRUCKEE RWER IN NEVADA1
Authors: Cobourn John
Published: June 2007

ABSTRACT: The Truckee River is a vitally important water source for eastern California and western Nevada. It runs 100 miles from Lake Tahoe to Pyramid Lake in the Nevada desert and serves urban populations in greater Reno‐Sparks and agricultural users in three Nevada counties. In the 1980s and 1990s, a number of state and local groups initiated projects which, taken collectively, have accomplished much to improve watershed management on the Truckee River. However, the task of writing a management plan for the entire watershed has not yet been undertaken. Key players in state, federal and local government agencies have instead chosen to focus specific improvement efforts on more manageable, achievable goals. The projects currently underway include a new agreement on reservoir operation, restoration of high priority sub‐watersheds, public education and involvement, water conservation education, and water resource planning for the major urban population centers. The approach which has been adopted on the Truckee River continues to evolve as more and more people take an interest in the river's future. The many positive projects underway on the watershed are evaluated in terms of how well they meet the definition of the ambitious water resources strategy, “integrated watershed management.”