bluuebunny/crossref_metadata_2025 huggingface dataset:
SIMULTANEOUS EQUATION SYSTEMS: A CONSISTENT ESTIMATOR FOR UNKNOWN PARAMETERS IN CONFINED AQUIFERS1
Authors: Loaiciga Hugo A. , Mariño Miguel A.
Published: June 2007

ABSTRACT: This paper presents criteria for establishing the identification status of the inverse problem for confined aquifer flow. Three linear estimation methods (ordinary least squares, two‐stage least squares, and three‐stage least squares) and one nonlinear method (maximum likelihood) are used to estimate the matrices of parameters embedded in the partial differential equation characterizing confined flow. Computational experience indicates several advantages of maximum likelihood over the linear methods.
IDENTIFICATION OF AQUIFER DISPERSIVITIES: METHODS OF ANALYSIS AND PARAMETER UNCERTAINTY1
Authors: Yeh William W‐G. , Wang Chuching
Published: June 2007

ABSTRACT: This paper presents a method for estimating aquifer dispersivities in solute transport models. Sensitivity equations are derived for the calculation of sensitivity coefficients. A modified Gauss‐Newton algorithm is used to perform the least‐squares minimization. A statistical procedure is outlined to assess reliability of the estimated parameters. The solute transport model is solved by the upstream weighted, multiple cell balance method which combines the concepts of local mass balance and finite element approximations. A one‐dimensional solute transport problem in a vertical column system is first used to illustrate the inverse technique. A second example considers the parameter identification problem for three‐dimensional solute transport with a unidirectional steady and uniform flow field. The third example solves the parameter identification problem in a three‐dimensional, stream‐aquifer, solute transport system with steady state flow. Numerical experiments are conducted to study data requirements for parameter identification.
AN EXAMINATION OF RELATIVE PERMEABILITY RELATIONS FOR TWO‐PHASE FLOW IN POROUS MEDIA1
Authors: Demond Avery H. , Roberts Paul V.
Published: June 2007

ABSTRACT: A key parameter in modeling two‐phase flow phenomena is relative permeability. It is important to understand which variables influence relative permeability, especially since so few measurements of relative permeability have been made for typical contaminants at hazardous waste sites. This paper focuses on the effect of five variables on relative permeability: intrinsic permeability, pore‐size distribution, viscosity ratio, interfacial tension, and wettability, by critically reviewing previously published relative permeability experiments. The wide variability in the functional relationship between relative permeability and saturation should be considered in attempts to model two‐phase flow.
APPLICABILITY OF THE t‐TEST FOR DETECTING TRENDS IN WATER QUALITY VARIABLES1
Authors: Montgomery Robert H. , Loftis Jim C.
Published: June 2007

ABSTRACT:A major concern in managing water resources is whether or not water quality variables have changed over time or space. The two‐sample Student's t‐test is probably the most commonly used statistical test for this purpose. Given that the underlying assumptions of the test may often be violated by water quality variables, a major concern regarding applicability of the test arises. This paper reviews and synthesizes available information in order to examine the effects of non‐normality, unequal variances, serial dependence, and seasonality on the performance of the two‐sample t‐test. The results suggest the t‐test is robust for non‐normal distributions if the distributions have the same shape (either symmetric or skewed) and sample sizes are equal. The t‐test is also robust for unequal variances if the sample sizes are equal. The t‐test appears not to be robust when: 1) samples come from two distributions of different shape, 2) samples have unequal variances and unequal sample sizes, 3) serial dependence in observations is present, or 4) seasonal changes, in concentration are present and not removed.
SUSPENDED SEDIMENT AND TURBIDITY FOLLOWING ROAD CONSTRUCTION AND LOGGING IN WESTERN MONTANA1
Authors: Anderson Bruce , Potts Donald F.
Published: June 2007

ABSTRACT: Forest management activities in a second order drainage basin increased suspended sediment yields 7.7 fold in the first year following road construction, and two‐fold following logging in the second year. Sediment supply limitations resulted in poor correlations between sediment concentrations with discharge. Sediment transport was strongly hysteretic, with the highest sediment concentrations occurring on the rising limbs of snowmelt hydrographs and individual peaks. In addition to discharge, hydrograph characteristics such as limb, dQ/dt, and the product of dQ/dt and limb aided in explaining variability of observed sediment concentrations. Sediment‐turbidity relationships were strongly discharge dependent, reflecting the changing composition of the suspended load with stream power and sediment supplies.
APPLICATION OF SELECTED SOIL LOSS EQUATIONS TO TRAMPLED SOIL CONDITIONS1
Authors: Savabi M. Reza , Giffor Gerald F.
Published: June 2007

ABSTRACT: Soil loss prediction equations (Universal Soil Loss Equation, Modified Universal Soil Loss Equation, and Onstad‐Foster Method) were modified to reflect the impact of trampling on soil erosion. The erosion control practice factor, P, was replaced by a trampling ratio, Tr, which is a function of the change in soil erosion due to animal trampling. Trampling impact on soil erosion varied With soil type. The data are a preliminary attempt to account for the impact of trampling on soil erosion.
BASINWIDE WATER‐BALANCE MODELING WITH EMPHASIS ON SPATIAL DISTRIBUTION OF GROUND WATER RECHARGE1
Authors: Sophocleous Marios , McAllister J. A.
Published: June 2007

ABSTRACT: A detailed but simple hydrologic budget for the entire Rattlesnake Creek basin (3,768 km2) in south‐central Kansas was developed. With this budget, using minimal daily‐weather input data and the soil‐plant‐water system‐analysis methodology, we were able to characterize the spatial distribution of the hydrologic components of the water balance within the basin. A combination of classification and meteorological methods resulted in a basinwide integration methodology. Using this methodology, we found that, in addition to obvious climatic controls, soil, vegetation, and land‐use factors also exert considerable influence on the water balance of the area. The available‐water capacity (AWC) of soil profiles plays a dominant role in soil‐water‐deficit development and deep drainage. Vegetation and dryland or irrigated farming particularly affect the evapotranspiration (ET) components, with ET from irrigated corn and alfalfa being two to three times that from wheat. Deep drainage from irrigated wheat fields was found to be significantly higher than that from grassland and dryland wheat; deep drainage from alfalfa is practically nonexistent. We demonstrated how vegetation changes may affect components of the hydrologic cycle. We also showed that different portions of the watershed have different water‐balance components and that use of single average values of hydrologic variables in management practices may not be realistic.
RAPID WATER TABLE RESPONSES TO RAINFALL IN A NORTHERN PEATLAND ECOSYSTEM1
Authors: Heliotis Francis D. , DeWitt Calvin B.
Published: June 2007

ABSTRACT: Two types of rapid water table responses to rain were observed in a northern Michigan peatland. The first, called the Lisse effect, occurred during rains of high intensity when the infiltrating water acted as a tightly closing lid that forced the water table to rise to the level required to compensate for the pressure increase. The second, called the Wieringermeer effect, was a rapid rise of the water table to the surface due to the conversion of capillary to phreatic water and was always followed by an equally rapid decline after cessation of the rainfall. We simulated these phenomena in the laboratory and estimated the critical parameters that determine their occurrence. The recognition of the importance of the capillary fringe is essential in evaluating the role of wetlands in flood control and in wastewater treatment.
COMPARISON OF RESERVOIR LINEAR OPERATION RULES USING LINEAR AND DYNAMIC PROGRAMMING1
Authors: Bhaskar Nageshwar Rao , Whitlatch E. Earl
Published: June 2007

ABSTRACT: Mathematical optimization techniques are used to study the operation and design of a single, multi‐purpose reservoir system. Optimal monthly release policies are derived for Hoover Reservoir, located in Central Ohio, using chance‐constrained linear programming and dynamic programming‐regression methodologies. Important characteristics of the former approach are derived, discussed, and graphically illustrated using Hoover Reservoir as a case example. Simulation procedures are used to examine and compare the overall performance of the optimal monthly reservoir release policies derived under the two approaches. Results indicate that, for the mean detention time and the corresponding safe yield target water supply release under existing design of Hoover Reservoir, the dynamic programming policies produce lower average annual losses (as defined by a two‐sided quadratic loss function) while achieving at least as high reliability levels when compared to policies derived under the chance‐constrained linear programming method. In making this comparison, the reservoir release policies, although not identical, are assumed to be linear. This restricted form of the release policy is necessary to make the chance‐constrained programming method mathematically tractable.
OXIDIZED NITROGEN IN PRECIPITATION, THROUGHFALL, AND STREAMFALL FROM A FORESTED WATERSHED IN OKLAHOMA1
Authors: Lawrence Stephen J. , Wigington Parker J.
Published: June 2007

ABSTRACT: Oxidized nitrogen (nitrite + nitrate N) concentrations were measured from bulk precipitation, bulk through‐fall, and streamflow in a 7.86 hectare forested watershed in southeastern Oklahoma during the wet season from March through June 1983. Oxidized nitrogen inputs comparable to results of other studies were recorded during the 19 rainstorms sampled. Oxidized nitrogen concentrations appeared to increase after rainfall interacted with the pine and hardwood canopies and were inversely related to both rainfall and through‐fall depth. Oxidized N concentrations in streamflow were greatest during the rising limb of storm flow with subsequent decreases during the falling limb of storm hydrographs and lowest during base flow. The oxidized N inputs from bulk precipitation were considerably greater than outputs from streamflow resulting in a net retention of oxidized nitrogen within the watershed during the study period.
MODELING THE EFFECTS OF URBANIZATION ON BASIN WATER YIELD AND RESERVOIR SEDIMENTATION1
Authors: Arnold J. G. , Bircket M. D. , Williams J. R. , Smith W. F. , McGill H. N.
Published: June 2007

ABSTRACT: The dam impounding White Rock Lake was completed in 1910 to provide water for the City of Dallas. Since then, land use on the watershed has changed from entirely rural to over 77 percent urban. A model called SWRRB (Simulator for Water Resources in Rural Basins) was utilized to determine the effect of urbanization on water and sediment entering the lake. The simulation results show that, if urbanization had not occurred, then the annual surface runoff would be 135 mm rather than 151 mm and the annual sediment yield would be 4.4 t/ha rather than 4.1 t/ha. Also, the effect of urbanization on delivery ratios was shown and a positive linear correlation was found. Finally, the weather generator in SWRRB was utilized to estimate the loss of reservoir capacity until 2050 for three different land use management scenarios.
WATER BALANCE OF PACIFIC ATOLLS1
Authors: Nullet Dennis
Published: June 2007

ABSTRACT: This study presents an estimate of water balance components for Pacific atolls under average dimatological conditions. Figures show annual potential evapotranspiration, annual recharge for rain‐fed and aquifer‐fed vegetated areas, and the number of months that potential evapotranspiration exceeds actual evapotranspiration (indicating water stress) under average conditions. The method relies on the assumption that small islands have minimal influence on cloudiness and precipitation. The potential evapotranspiration is computed using the equilibrium evaporation concept, and estimates of monthly soil water storage and recharge follow Thornthwaite's bookkeeping method. Gradients in potential evapotranspiration run primarily north‐south, though for the equatorial zone potential evapotranspiration declines from east to west, opposing the trend in rainfall. Recharge estimates range from 250 mm in the central Tuamotu Archipelago and zero in eastern Kiribati to over 2000 mm per year in the southern Caroline Islands (U.S. Trust Territory) and Solomon Islands. The sensitivity of the model to intra‐month rainfall variability and a range of available soil moisture values is discussed.
USE OF STREAMFLOW INCREASES FROM VEGETATION MANAGEMENT IN THE VERDE RIVER BASIN1
Authors: Brown Thomas C. , Fogel Martin M.
Published: June 2007

ABSTRACT: Although the effects of vegetation management on streamflow have been studied in many locations, the effects of augmented streamflow on downstream water users have not been carefully analyzed. This study examines the routing of streamflow increases that could be produced in the Verde River Basin of Arizona. Reservoir management and water routing to users in the Salt River Valley around Phoenix were carefully modeled. Simulation of water routing with and without vegetation modification indicates that, under current institutional conditions, less than one‐half of the streamflow increase would reach consumptive users as surface water. Most of the remainder would accumulate in storage until a year of unusually heavy runoff, when it would add to reservoir spills. Under alternative scenarios, from 39 to 58 percent of the streamflow increase was delivered to consumptive users.
400 YEARS OF CENTRAL CALIFORNIA PRECIPITATION VARIABILITY RECONSTRUCTED FROM TREE‐RINGS1
Authors: Michaelsen Joel , Haston Laura , Davis Frank W.
Published: June 2007

ABSTRACT: Coastal central California is a region that has never been the subject of tree‐ring studies. New tree‐ring chronologies developed from cores of big cone spruce (Pseudotusuga macrocarpa (Torr.) Mayr.) growing in the Transverse Ranges of central Santa Barbara county were used to reconstruct precipitation fluctuations for this region. To verify the new reconstructions, calibration with recorded rainfall using cross‐validation, comparison with other reconstructions, and documentary evidence from historical sources were utilized. The precipitation reconstructions show that there have not been fluctuations in mean precipitation on time scales longer than 30 years, but there have been major fluctuations in precipitation variability including changes in the frequency of extremes and rare events that have not occurred in the modern record.
DESIGN OF AN INDEX OF WATER QUALITY1
Authors: Dinius S. H.
Published: June 2007

ABSTRACT: This paper describes the formulation of an Index of Water Quality to evaluate the level of pollution in fresh water. A Four‐Round Delphi equation, using a panel of seven nationally recognized water scientists, was performed to ascertain the pollutants to be included in the index, the relationship between the quantity of these pollutants in the water and the resulting quality of the water, and the importance of each pollution variable to each water use as well as to overall pollution. A multiplicative index was used to bring the pollutants together into one system.
CATCHMENT RESPONSE TIME AS A PREDICTOR OF FLOOD QUANTILES1
Authors: Potter Kenneth W. , Faulkner Ellen Baldwin
Published: June 2007

ABSTRACT: A regression analysis using a generalized least squares approach on flow data from the driftless area of Wisconsin indicates that the ratio of drainage area to time‐to‐peak is a good predictor of flood quantiles. The estimation of time‐to‐peak (or some other measure of basin response time) requires direct measurement of river stage and possibly rainfall at the site of which the quantiles are to be estimated. The cost‐effectiveness of such an approach must yet be determined.
CONTRIBUTIONS OF RAINFALL TO CONSTITUENT LOADS IN STORM RUNOFF FROM URBAN CATCHMENTS1
Authors: Ebbert J. C. , Wagner R. J.
Published: June 2007

ABSTRACT: Rainfall is a significant source of some constituents, particularly nitrogen species, in storm runoff from urban catchments. Median contributions of rainfall to storm runoff loads of 12 constituents from 31 urban catchments, representing eight geographic locations within the United States, ranged from 2 percent for suspended solids to 74 percent for total nitrite plus nitrate nitrogen. The median contribution of total nitrogen in rainfall to runoff loads was 41 percent. Median contributions of total‐recoverable lead in rainfall to runoff loads varied by as much as an order of magnitude between catchments in the same geographic location. This indicates that average estimates of rainfall contributions to constituent loading in storm runoff may not be suitable in studies requiring accurate constituent mass‐balance computations.
FECAL COLIFORM CONCENTRATIONS IN RUNOFF FROM A GRAZED, RECLAIMED SURFACE MINE1
Authors: Boyer D. G. , Peny H. D.
Published: June 2007

The relatively scarcity of flat or moderately sloping land in Central Appalachia make reclaimed surface mined lands attractive for agricultural uses. A reclaimed surface coal mine in southern West Virginia was placed under grazing management during the 1984 and 1985 growing seasons. Discharge was collected from summer‐grazed watersheds of about 2.8 ha and 8.9 ha and analyzed, by the membrane‐filtration method, for fecal coliforms (FC). Prior to grazing, in 1984, FC counts were < 20/100 ml. During the grazing season, FC ranged from <0/100 ml to> 1000/100 ml in 1984 and from 0/100 ml to > 2500/100 ml in 1985. FC counts remained high during warm periods for several months after grazing ceased. It was concluded that the bacteriological quality of receiving streams was impacted by grazing the reclaimed area and recommended standards for point sources were often exceeded; however, the FC counts did not appear to be any greater than what would have been expected from grazed, undisturbed areas. Reclaimed surface mine areas in Appalachia have the potential to be a valuable “flat land” resource and grazing appears to be an alternative post mine land use that affects bacteriological water quality in a similar manner as “natural” pastures. However, good management practices may be necessary to avoid bacterial contamination of adjacent bodies of water.
ASSESSING FLUSHING‐FLOW REQUIREMENTS FOR BROWN TROUT SPAWNING GRAVELS IN STEEP STREAMS1
Authors: Kondolf G. M. , Cada G. F. , Sale M. J.
Published: June 2007

Flushing flows are re1eses from dams designed to remove fine sediment from downstream spawning habitat. We evaluated flushing flows on reaches proposed for hydroelectric diversions on seven streams in the eastern Sierra Nevada, California, with wild populations of brown trout (Salmo trutta). The stream reaches are steep (average map slopes range from 7 to 17 percent), are dominated by boulder cascades, and afford few opportunities for gravel deposition. Methods for estimating flushing flows from flow records, developed from studies in other localities, produced widely differing results when applied to the study streams, probably reflecting differences in the hydrologic and geomorphic characteristics of the streams on which the methods were developed. Tracer gravel experiments demonstrated that all sampled gravels were washed out by the flows of 1986, a wet year. Size analyses of gravel samples and hydraulic data from field surveys were used in tractive‐force calculations in an attempt to specify the flow required to flush the gravels. However, these calculations produced some unrealistic results because the flows were nonuniform in the study reaches. This suggests that the tractive‐force approach may not be generally applicable to small, steep streams where nonuniform flow conditions prevail.
BIOECONOMIC CONSIDERATIONS FOR WASTEWATER REUSE IN AGRICULTURAL PRODUCTION1
Authors: Wilson Paul N. , Goldammer Teddy J. , Wade James C.
Published: June 2007

ABSTRACT: Urban wastewater can be a valuable source of water and plant nutrients for agricultural producers, particularly in arid regions. The scientific literature reveals cautious optimism concerning the biological, institutional, and economic viability of irrigating crops with secondary‐treated effluent. A derived effluent demand function for agricultural producers near Tucson, Arizona, reveals a potential annual demand of 11,000 acre‐feet under present price and proposed delivery system conditions. In this case, wastewater could be exchanged for ground water and both the urban and rural areas would gain.
INTERBASIN WATER TRANSFERS IN RIPARIAN STATES: A CASE STUDY OF GEORGIA1
Authors: Kundell James E.
Published: June 2007

ABSTRACT: Under the riparian doctrine of eastern states, transfers of water to nonriparian lands and, thus, to different river basins, are only possible if the natural flow theory has been modified to allow for reasonable use. Even this adaptation is too nebulous to provide water managers and water users with certainty regarding water transfers. To provide a more precise mechanism for allocating water, 14 eastern states have adopted some form of administrative permitting process. Of these, five states statutorily allow for interbasin transfers of water. Thus far, no states have successfully issued permits for interbasin water transfers but Georgia and South Carolina are positioned to do so. Whether the permitting process will deter court action may rest on the ability of affected parties to negotiate an equitable agreement.
AGRICULTURAL WATER MODELING AND ECONOMIC INFORMATION NEEDS UNDER THE MODEL WATER CODE1
Authors: Lynne Gary D.
Published: June 2007

ABSTRACT: Economic information for efficient water allocation is difficult and costly to acquire under administrative water systems evolving under the Model Water Code. One approach to obtaining more information is to use a simulator like the Florida AGWATER model. The advantage of AGWATER is the potential for realistic prediction, because it operates at the field and day levels, using detailed information for each crop and tract. Unfortunately, such simulators are complex and require large amounts of costly input data. A better solution to the information problem may be to use markets for the marketable goods associated with water, because information is inherent in such a process. This approach will allow limited modeling and management resources to be put into using water models to generate information for the goods dependent on water that are difficult to market, like wildlife services.
VALUING IRRIGATION WATER: A SIMULATION/MATHEMATICAL PROGRAMMING APPROACH1
Authors: Bernardo D. J. , Whittlesey N. K. , Saxton K. E. , Bassett D. L.
Published: June 2007

ABSTRACT: A two‐stage simulation/mathematical programming model was developed to derive irrigation water values that reflect efficient response to reduced water supplies. The failure of many previous water valuation studies to represent the dynamic dimension of irrigation was shown to result in overestimation of derived water values. Water values are also shown to be dramatically influenced by both application system characteristics, as well as the relative costs of irrigation inputs. Finally, the marginal value of irrigation water was shown to vary considerably over the irrigation season, reaching its maximum when atmospheric demand is highest and crops are most susceptible to water stress. Results presented should be of interest to policymakers investigating the viability of alternative water reallocation mechanisms.
PARAMETRIC AND NONPARAMETRIC TESTS FOR DEPENDENT DATA1
Authors: El‐Shaarawi A. H. , Damsleth Eivind
Published: June 2007

ABSTRACT: Simulation and analytical results show that ignoring serial dependence can have serious effects on the performance of the t, sign, and Wilcoxen tests. In particular, the true significance levels of these tests are altered significantly from the intended nominal levels. Modifications for these tests are given and shown to have the correct significance levels. Furthermore, an estimate of serial correlation is suggested for binary data and evaluated by simulation. An application to the toxic contaminants data from the Niagara River concludes the paper.
NONPARAMETRIC TESTS FOR TREND DETECTION IN WATER QUALITY TIME SERIES1
Authors: Berryman David , Bobée Bernard , Cluis Daniel , Haemmerli John
Published: June 2007

ABSTRACT:A review of nonparametric tests for trend leads to the conclusion that Mann‐Whitney, Spearman, and Kendall tests are the best choice for trend detection in water quality time series. Recently these tests have been adapted to account for dependence and seasonality in such series (Lettenmaier, 1976; Hirsch,et al., 1972; Hirsch and Slack, 1984). For monotonic trends, a procedure allowing to select the pertinent tests considering the characteristics of time series is proposed and the practical limitations of the tests are also brought out. This procedure has been applied to identify the appropriate trend detection test for the time series of nine water quality parameters at Lake Laflamme (Québec). When a time series can be tested with the Mann‐Whitney, Kendall, Spearman, or Lettenmaier (1976) test, the number of observations required to detect trends of a given magnitude, for selected significance and power levels can be calculated with the power function of the t test. When the test proposed by Hirsch,et al. (1984), Hirsch and Slack (1984), or Farrell (1980) need to be used, the number of observations can only be estimated approximately from the results of empirical power studies.
SIMULATION OF REGIONAL GROUND WATER FLOW IN BEDROCK, SOUTHWESTERN NEW YORK‐NORTHWESTERN PENNSYLVANIA1
Authors: Gould Gerald , Siegel D. I.
Published: June 2007

ABSTRACT: This paper presents the results of steady‐state three‐dimensional computer simulations to determine the hydrogeologic setting of formation water in the hydrocarbon producing formations of southwestern New York and northwestern Pennsylvania. Recharge areas for the regional ground water flow systems in the study area are the Valley Heads Moraine and Allegheny uplands; discharge areas are Lakes Erie and Ontario to the north and the northern margin of the Appalachian basin to the south.

Simulated ground water flow in all model layers moves north from the ground water divide on the Valley Heads Moraine towards Lake Erie at a rate from 10−‐6 to 10−‐3 ft/day. South of the divide intermediate‐scale and local‐scale flow systems occur in the upper 4000 feet of the stratigraphic section and the directions of ground water flow diverge towards major rivers and other topographically low areas.
STREAM CHEMISTRY IN THE SOUTHERN BLUE RIDGE: FEASIBILITY OF A REGIONAL SYNOPTIC SAMPLING APPROACH1
Authors: Messer Jay J. , Ariss Charles W. , Baker John R. , Drousé Sevdâ K. , Eshleman Keith N. , Kinney Andrew J. , Overton W. Scott , Sale Michael J. , Schonbrod Robert D.
Published: June 2007

ABSTRACT: A pilot study, which was conducted in the Southern Blue Ridge geographical province of the Southeastern U.S., demonstrated the feasibility of a probability‐based regional synoptic design for the National Stream Survey, which is a project aimed at estimating the number and percentage of streams in various regions of the U.S. that are acidic or at risk from acid deposition. Estimated population distributions for key chemical variables were not appreciably affected by week‐to‐week variability in stream chemistry during the spring index period chosen for the study. Differences were observed in estimated acid neutralizing capacity (ANC), nitrate, and pH frequency distributions between spring and summer. Observations made at the downstream node did not represent the chemistry of the entire reach for some variables (ANC and nitrate) as indicated by differences in chemical concentrations between upstream and downstream sampling locations. Coefficients of variation in chemical species were low enough to provide a reasonably stable classification of streams based on ANC. Although median ANC, sulfate, and nitrate concentrations were quite low in the region, the probability of finding streams with ph < 6.3 is less than 1.3 percent at the α= 0.05 confidence level.
SEDIMENT NUTRIENT FLUXES IN A TIDAL FRESHWATER EMBAYMENT1
Authors: Cerco Carl F.
Published: June 2007

ABSTRACT: Sediment‐water exchanges of ammonium, nitrate, and phosphate are incorporated into a eutrophication model of Gunston Cove, Virginia. The exchange rates are obtained from laboratory measurements and are modeled as empirical functions of temperature, concentration, and pH. Simulation of the period from June 1 to September 30, 1983, indicates nitrogen, phosphorus, and chlorophyll ‘a’ are correctly modeled only when the sediment‐water nutrient exchanges are taken into account.
DERIVING THE NONLINEAR RISK‐BENEFIT ALGORITHM FOR RESERVOIRS1
Authors: Uan‐On Thanakorn , Helweg Otto J.
Published: June 2007

ABSTRACT: The Nonlinear Risk‐Benefit (NRB) Algorithm includes risk as one of the objectives in a multiple‐objective optimization problem. The NRB Algorithm is derived by extending the Surrogate Worth Trade‐Off method to quadratic programming. This category of problem is common in water resources planning and design, especially multipurpose reservoir systems. Consequently, an example is given using the algorithm for optimally operating a multipurpose reservoir.
EXPERIMENTAL VERIFICATION OF MULTICOMPONENT GROUND WATER CONTAMINATION PREDICTIONS1
Authors: Clancy Kathleen M. , Jennings Aaron A.
Published: June 2007

ABSTRACT: Recent advances in mass transport modeling have made possible computation of the theoretical consequences of intricate multicomponent species interactions during ground water contamination events. Predictions such as strong chromatographic effects and induced downstream precipitations may have considerable impact on environmental analysis and regulation. Results of laboratory attempts to verify theoretical multicomponent transport predictions are discussed. Evidence presented here indicates that natural variability of soil properties make such verifications difficult. Although species interactions are easily confirmed, dramatic effects often exist only within small mathematical windows in strongly variable coefficient sets. Currently, the ability to generate multicomponent predictions apparently exceeds the ability to quantify the necessary, presumably deterministic, information required for real soils.
INFILTRATION AND WATER QUALITY ON RANGE SITES AT FORT STANTON, NEW MEXICO1
Authors: Wood James C. , Wood M. Karl.
Published: June 2007

ABSTRACT: The hydrologic impacts of livestock grazing schemes on selected plant communities and soils at Fort Stanton, New Mexico, were evaluated. Simulated rainfall was applied to 1 m2plots. On a mesa‐top, infiltration rates for a grassland livestock exclosure and a pinyon pine‐juniper community closely approximated each other and were significantly greater (P = 0.10) than either a moderate continuous or a heavy continuous treatment in a grassland community. Sediment concentration from the heavy continuous treatment was more than twice that of the other treatments. Infiltration rates on the hillside site were highest in a pinyon pine‐juniper community receiving short duration grazing. Infiltration for this treatment was found to be significantly higher (P = 0.10) than that of a short duration grazing treatment, but not from a rest rotation grazing treatment on grassland. The short duration grazing treatment on a grassland had the highest sediment concentration, while the rest rotation grazing on a grassland and the short duration pinyon pine‐juniper treatments were found to be similar. In the bottomland site, a fertilized and unfertilized treatment showed no significant difference in infiltration or sediment concentration, although twice as many animals were present on the fertilized treatment.
MODELING THE PERFORMANCE OF DEEP WASTE STABILIZATION PONDS1
Authors: Moreno Maria D. , Medina Miguel A. , Moreno Joaquin , Soler Antonio , Saez Jose
Published: June 2007

ABSTRACT: The performance characteristics of a deep waste stabilization pond operating in Southeast Spain were studied for one year; the results show a high reduction in organic load and nutrients, as well as disinfection of the effluent, after a retention time that varies as a function of climatic conditions. Mathematical models describing its hydraulic, thermal, and biochemical bahavior are presented and compared with a set of measured data.
MODEL PREDICTIONS OF WATERSHED EROSION COMPONENTS1
Authors: Hetrick D. M. , Travis C. C.
Published: June 2007

ABSTRACT: Model predictions for surface runoff and sediment yield from the coupled SESOIL/EROS soil compartment model are compared with empirical measurements from three watersheds. The model is summarized and descriptions are given for the two cornfield watersheds and one grassland watershed used in the analysis. Model performance and limitations are discussed. (KEY WORDS: soil erosion; sediment yield; soil compartment model.
PUBLIC INFORMATION AND CITIZEN INVOLVEMENT1
Authors: Grisham Alice
Published: June 2007

ABSTRACT: Public information, an important contributer to citizen involvement in the governmental decision making process, has traditionally been given a low priority by government agencies. However, citizens are becoming increasingly concerned about governmental decisions that affect their lives and are demanding more information about governmental activities, including information about water resource issues, Because of this active citizen interest and involvement, the role of public information in increasing citizen awareness is becoming more important.

Government officials and professionals should recognize that public information efforts also play an important role in achieving increased credibility and respect for their agencies. Once an agency recognizes the importance of public information and decides to initiate a public information program, careful planning is required to develop a program that addresses the needs of both the citizens and the agency. Two of the most flexible and cost effective ways to get information to the publié are through publications and public meetings. Both can be easily adapted to suit the needs of specific audiences and projects.

A successful public information program can be carried out at a relatively low cost, but it requires a substantial amount of time and energy. The commitment of time and energy for this purpose is a good investment, however, because an effective public information program can play a significant role in improving the quality of governmental decisions through the increased involvement of the citizenry.
FRACTALS AND THE RIVER‐LENGTH CATCHMENT‐AREA RATIO1
Authors: Hjelmfelt Allen T.
Published: June 2007

ABSTRACT: The fractal nature of stream‐length and catchment‐area measurement is investigated using eight rivers in Missouri. The fractal dimension for the length measurement was found to average 1.158 and for area to average 1.0105. These values are close to those hypothesized by Mandeibrot (1983).
BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1
Authors: Sindermann Carl J.
Published: June 2007

ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish ‐ their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species ‐ probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.
SMALL FISH MODELS FOR IDENTIFYING CARCINOGENS IN THE AQUEOUS ENVIRONMENT1
Authors: Hawkins William E. , Overstreet Robin M. , Walker William W.
Published: June 2007

ABSTRACT: Contaminants in water and sediments can be carcinogenic to aquatic wildlife as well as humans. Identifying those carcinogens, however, is difficult because they often occur in low concentrations and exert their effects over a large part of the life span of affected organisms. Furthermore, the carcinogens are often components of complex mixtures. Recent studies suggest that laboratory‐reared fish species might be well suited for testing water‐associated and other carcinogens. Here, we review the principal carcinogen exposure methods that utilize small fish species or can be adapted to utilize small fish species to detect carcinogens in aqueous environments. Emphasis is placed on methods for which the end‐point is tumor induction. The methods discussed are dietary exposures, skin painting, embryo microinjection, early life stage (pulse) exposures, static water exposures, flow‐through exposures, and controlled field exposures. Early life stage exposures seem to have the greatest utility with regard to carcinogen sensitivity, ease of administration, disposal of test compounds, and economy of materials and effort. For certain types of carcinogens, however, long‐term flow‐through exposures are probably required. In summary, small fish carcinogenesis models offer an array of methodologies that can be utilized in a variety of combinations depending on compounds tested, exposure parameters employed, and end points sought.
CAGED FISH AS MONITORS OF POLLUTION: EFFECTS OF CHLORINATED EFFLUENT FROM A WASTEWATER TREATMENT PLANT1
Authors: Grizzle John M. , Horowitz Stephen A. , Strength D. Ralph.
Published: June 2007

ABSTRACT: Fish confined to cages were used to determine the effects of effluent from a wastewater treatment plant (WWTP). Control fish were kept in cages in an aquaculture pond. Acute effects of the effluent entering the final oxidation pond of the WWTP were determined by confining channel catfish (Ictalurus punctatus) at the pond inlet; the mean total residual chlorine (TRC) concentration was 0.9 mg/l during this exposure. After 8 h, 42 percent of the fish had died and survivors had severe lesions of the skin and gills. During the first two weeks of exposure, channel catfish at the outlet of the final oxidation pond (mean TRC=0.1 mg/l) were predisposed to bacterial infection but lost the parasitic trematodes that were on the gills when the fish were placed in cages. After several weeks, exposed fish had histologic lesions, enlarged livers, and reduced growth. The presence of unidentified carcinogen(s) in the effluent of this WWTP was indicated by papillomas developing on caged black bullheads (Ictalurus melas) and hepatic‐enzyme induction in channel catfish. In situ exposure of caged fish was advantageous because storage and pretreatment of water samples were not required, and exposure levels corresponded to those present in the environment. The use of cages for containment of fish during field exposure allowed confinement to the location of interest and convenient sampling of the fish. Unlike wild fish, the caged fish could be compared to control fish with the same pre‐exposure history.
DETERMINING THE RELATIONSHIP BETWEEN WATER QUALITY AND INFECTIOUS DISEASE IN FISHERY POPULATIONS1
Authors: Noga Edward J.
Published: June 2007

ABSTRACT: Diseases in wild fish populations may have multiple economic and social impacts. Epidemics of infectious diseases, which are associated with the presence of some microbe or parasite, have recently been observed in several major estuarine systems in the eastern United States. The most prevalent of these problems is ulcerative mycosis (UM), a fungal infection. The agents responsible for UM and many of these other diseases are opportunistic pathogens that are not believed to infect normal, immunocompetent individuals. While inroads have been made into determining the infectious agents associated with these diseases, we know very little of how pollution may influence their prevalence. Understanding the importance of pollution requires an awareness of all the environmental conditions that can affect the health of wild populations. In this paper, a multistep examination of the interactions between the host, pathogen(s), and environment is outlined.
A MULTIOBJECTIVE, DISCRETE SYSTEM REPRESENTATION OF RANGELAND WATERSHEDS1
Authors: Khalili Davar , Duckstein Lucien , Fogel Martin M.
Published: June 2007

ABSTRACT: Resource utilization as practiced by humans is identified as the main cause of the degradation of rangeland watersheds, a process referred to as desertification. This paper introduces a multi‐objective decision making methodology for the selection of a plan which if implemented should limit the desertification process. The evaluation objectives are measured by quantitative and qualitative criteria. The quantitative criteria provide the performance level for production and sediment yield, while the qualitative criteria give such information as public acceptance of a particular alternative or worth of an appropriate wildlife habitat. A system model is applied to describe the dynamics of a range site in response to climatic and human inputs. As such it provides the information required by the quantitative criteria as well as a range condition index that identifies the productivity of a given range site. A multiobjective selection procedure is presented that will lead to the appropriate technique from an available set, in this case ESAP, Environmental Sensitivity Analysis Package. Four individuals with diverse backgrounds in natural resource management participated as decision makers and decided on their preferred alternatives. Finally, ranked alternatives in agreement with all of the decision makers were obtained.
INTERREGIONAL COMPARISON OF ALLUVIAL STREAM CHANNEL MORPHOLOGY: GREAT PLAINS VERSUS CENTRAL LOWLANDS1
Authors: Miller Theodore K. , Onesti Lawrence J.
Published: June 2007

ABSTRACT: Stream channel development is a complicated process involving many factors. A major goal of research in fluvial geomorphology is to develop an understanding of the relations between channel form, water discharge, and sediment discharge characteristics. The concept of thresholds has been introduced as an element in fluvial processes, with the implication that the factors involved in a process might change in some way as threshold boundaries are passed. This study is focused on the extent to which a particular regional boundary represents a threshold in the process of stream channel development. Twenty‐four alluvial stream channels from the Great Plains region and 24 from the Central Lowlands region are compared with regard to the distributional form, central tendency and dispersion characteristics, and correlation structure of ten variables, including indicators of discharge, channel sediment, and channel morphology. The results suggest that these aspects of the data are very similar between the regions, except for certain differences in central tendency characteristics, which are assumed to reflect underlying differences between the regions in geology and climate. In general, the results support the idea that this regional boundary is not an effective threshold with respect to the stream channel development process, and that, therefore, stream channels develop in these environmentally distinct regions by way of a similar process.
TESTS OF THE CREAMS MODEL ON AGRICULTURAL FIELDS IN VERMONT1
Authors: Jamieson Catherine A. , Clausen John C.
Published: June 2007

ABSTRACT: The computer model, CREAMS, has been developed for field‐sized agricultural areas to aid in best management practices evaluation and planning. A test of CREAMS was performed by comparing monthly observed and simulated values for runoff, sediment, and phosphorus exports from two agricultural fields in Vermont to determine the applicability of the model in cold climates. Water quality samples were collected from field runoff and analyzed for both total suspended solids and total phosphorus. Generally, exports were overestimated during low flow months and underestimated during high flow months. Significant r2values (p <0.05), ranging from 0.78 to 0.90, between simulated and observed data were found for all comparisons except for sediment export from one field. Comparisons of the slopes of the regressions between observed and simulated values and the ideal slope of one using t‐tests revealed significant differences between simulated and observed monthly runoff, sediment, and phosphorus exports. It is postulated that this lack of adequate prediction could be attributed to the use of average monthly, instead of daily, temperature and solar radiation in calculations of evapotranspiration and snowmelt, and the use of static parameter values for parameters that vary seasonally.
STORMWATER HARVESTING IN THE URBAN WATERSHEDS OF ARID ZONES1
Authors: Ishaq Achi M. , Khararjian Hraj A.
Published: June 2007

ABSTRACT: A representative city in an arid zone, such as the Kingdom of Saudi Arabia, is instrumented to determine the quantity and quality of storm runoff with a view to investigating the possibility of using it for industrial and agricultural purposes after appropriate treatments. In an urban watershed in the City of Dhahran, Saudi Arabia, quantity and quality of storm runoff had been monitored for the past six years, and the average annual runoff that can be harvested was determined. The quality of runoff is well within the range of possible reuse schemes, most notably for restricted irrigation. Treatment schemes for the harvested water are proposed.
MODELING WATER UTILIZATION IN LARGE‐SCALE IRRIGATION SYSTEMS: A QUALITATiVE RESPONSE APPROACH1
Authors: Ferguson Carol A.
Published: June 2007

ABSTRACT: Given limited available data and the present state of knowledge on the social aspects of irrigation, there is a need to develop new quantitative methods to measure water management performance in large‐scale systems. A qualitative response framework is adapted to formulate a dynamic logit model of weekly field water adequacy and quantify indirectly farmer water utilization. Model parameters are estimated in a weighted least‐squares regression using four seasons of data from a Philippine canal system. Estimated coefficients and independent model forecasts indicate greater effective use of rainfall than irrigation in sustaining high levels of water adequacy during the rainy season. Irrigation utilization is two times higher in the dry season, while system location has a much smaller but still significant impact. Utilization rates for both rain and irrigation showed considerable responsiveness to the prevailing scarcity of water. The qualitative response approach is well suited to the aggregated data available for large‐scale systems, and allows advances in modeling dynamic water management behavior. Formal evaluation of the model will require further empirical applications.