bluuebunny/crossref_metadata_2025 huggingface dataset:
APPLICATION OF COMPUTER INTENSIVE STATISTICS TO PARAMETER UNCERTAINTY IN STREAMFLOW SYNTHESIS1
Authors: Cover K. A. , Unny T. E.
Published: June 2007

ABSTRACT:This paper introduces the application of Computer Intensive Statistics (CIS) to the evaluation of parameter uncertainty with specific reference to the parameters in the ARMA models used in the synthesis of streamflows. The CIS provides an empirically derived joint distribution for all parameters. Random values from this distribution can be drawn for application in the model for the generation of a specific synthetic sample. The CIS originally proposed by Efron and discussed herein is of general applicability in the evaluation of uncertainty in any statistic derived from a set of data. Some comments and limitations of the CIS are discussed in the concluding remarks.
ENVIRONMENTAL DESIGNS FOR STREAMBANK PROTECTION PROJECTS1
Authors: Henderson Jim E.
Published: June 2007

ABSTRACT:Streambank protection projects are intended to prevent streambank erosion, thereby preventing streambank failure and maintaining a desirable channel alignment. Streambank erosion is a natural process of unaltered, dynamic river systems, and protection projects seek to impose stability on this natural system. The environmental impacts of such projects are primarily changes to terrestrial and aquatic habitats and to aesthetics. Adverse environmental impacts have been minimized and enhancement of existing habitat and aesthetics have been achieved through the development of new, innovative designs or modifications to existing designs and through use of construction and maintenance practices that promote habitat and aesthetics. Designs based on channel flow characteristics, e.g., revetments using a variety of structural materials, can result in preservation of wildlife habitat by reducing the use of structural protection by matching the erosion potential of flow at the bank with the protection capability of the materials used. Designs based on streambed stabilization prevent bank failure caused by bank undermining, result in preservation or establishment of streamside vegetation, and enhance aesthetics. Protection schemes that manage and preserve floodplains, berms, and riparian areas preserve the natural condition of the floodplain area. Designs based on deflection of erosive flows, e.g., dikes, minimize disturbance to the bank vegetation and create low‐velocity aquatic habitats. Use of vegetation for bank protection is most effective when used in combination with structural components. Construction and maintenance practices can be scheduled and modified to minimize impacts to floodplain areas and to enhance wildlife habitat while preserving the integrity of the protection structure.
EFFECT OF RAINFALL EXCESS CALCULATIONS ON MODELED HYDROGRAPH ACCURACY AND UNIT‐HYDROGRAPH PARAMETERS1
Authors: Garklavs George , Oberg Kevin A.
Published: June 2007

ABSTRACT:Two methods of computing rainfall excess in the U.S. Army Corps of Engineers’flood hydrograph package (HEC‐1), the Initial and Uniform method and the Exponential method, are compared to evaluate the effects on modeled hydrograph accuracy. Two computed unit‐hydrograph parameters, time of concentration and storage coefficient, were also compared. Rainfall and runoff data from 209 storms in 32 gaged basins in Illinois were used to calibrate the HEC‐1 model. Three hydrograph characteristics ‐ sum of incremental flows, peak discharge, and time of peak discharge ‐ were used to evaluate modeled hydrograph accuracy. Mean percent error for each basin and hydrograph characteristic was computed. An evaluation of the mean errors indicates that, although some bias in modeled hydrograph accuracy is evident, rainfall excess computed using either method results in a computed hydrograph accuracy that is within generally accepted limits. Application of a linear‐regression model shows no significant differences in computed values of unit‐hydrograph parameters.
HISTORY OF THE FEDERAL‐STATE COOPERATIVE WATER RESOURCES RESEARCH INSTITUTE PROGRAM1
Authors: Burton James S.
Published: June 2007

ABSTRACT: This paper presents a condensed history of the State Water Resources Research Institute Program, which evolved from the Water Resources Research Act of 1964, as amended, the Water Research and Development Act of 1978, Public Law (P.L.) 96–457, and the Water Research and Development Act of 1984. These laws authorized the following components of the Institute Program: (1) the annual allotment and matching grants program for the Institutes, and (2) the additional and saline water research programs for organizations in addition to the State Water Resources Research Institutes. The paper covers the legislative history of the Institute Program and reviews authorized and appropriated funds for the program from fiscal year 1965 to fiscal year 1986. It also discusses the Institutes’role in conducting and sponsoring water‐resources research and development, training of scientists and engineers, and coordinating, disseminating, and transferring water‐research results. The State Water Resources Research Program has been administered by the Office of Water Resources Research (OWRR) (1964–1974), the Office of Water Research and Technology (OWRT) (1974–1982), the Office of Water Policy (OWP) (1982–1983), and the U.S. Geological Survey (USGS) (1983‐present).
COMPARISON OF STOCHASTIC AND DETERMINISTIC DYNAMIC PROGRAMMING FOR RESERVOIR OPERATING RULE GENERATION1
Authors: Karamouz Mohammad , Houck Mark H.
Published: June 2007

ABSTRACT: Two dynamic programming models — one deterministic and one stochastic — that may be used to generate reservoir operating rules are compared. The deterministic model (DPR) consists of an algorithm that cycles through three components: a dynamic program, a regression analysis, and a simulation. In this model, the correlation between the general operating rules, defined by the regression analysis and evaluated in the simulation, and the optimal deterministic operation defined by the dynamic program is increased through an iterative process. The stochastic dynamic program (SDP) describes streamflows with a discrete lag‐one Markov process. To test the usefulness of both models in generating reservoir operating rules, real‐time reservoir operation simulation models are constructed for three hydrologically different sites. The rules generated by DPR and SDP are then applied in the operation simulation model and their performance is evaluated. For the test cases, the DPR generated rules are more effective in the operation of medium to very large reservoirs and the SDP generated rules are more effective for the operation of small reservoirs.
PREPLANTING SOIL MOISTURE USING PASSIVE MICROWAVE SENSORS1
Authors: Jackson T. J. , Hawley M. E. , O'Neill P. E.
Published: June 2007

ABSTRACT: Accurate assessment of preplanting soil moisture conditions is necessary for good agricultural management, and can have a significant influence on crop yield in the Texas Panhandle region. The Texas High Plains Underground Water Conservation District invests considerable time and money in developing a soil moisture deficit map each year in the hopes of achieving optimal use of irrigation water. Microwave sensors are responsive to surface soil moisture and, if used in this application, can provide timely and detailed information on root zone soil moisture. For this reason, an experiment was conducted in 1984 to evaluate the potential of aircraft‐mounted passive microwave sensors. Microwave radiometer data were collected over a 2700 km2 area near Lubbock, Texas, with a processed resolution of 0.32 km2. These data were ground registered and converted to estimates of soil moisture using an appropriate model and land cover and soil texture information. Analyses indicate that the system provides an efficient means for mapping variations in soil moisture over large areas.
PROJECTED INCREASES IN MUNICIPAL WATER USE IN THE GREAT LAKES DUE TO CO2‐INDUCED CLIMATIC CHANGE1
Authors: Cohen Stewart J.
Published: June 2007

ABSTRACT: Two scenarios of CO2‐induced climatic change are used to estimate changes in water use for a number of municipalities in the Great Lakes region of Canada and the United States. Both scenarios, based on General Circulation Models produced by the Goddard Institute for Space Studies (GISS) and Geophysical Fluid Dynamics Lab (GFDL), project warmer temperatures for the region. Using regression models based on monthly potential evapotranspiration for individual cities, it is projected that annual per capita water use will increase by a small amount, which will probably have only a marginal effect on water supplies in the Great Lakes basin. This method could also be used to assess the potential impacts of CO2‐induced climatic change on water use by the agriculture and power sectors, as well as the effectiveness of water policy initiatives, such as price changes. More work is needed to project water use during peak periods (warm dry spells), which may occur more frequently in a 2 × CO2 climate in this region.
MODELING COST‐EFFECTIVENESS OF AGRICULTURAL NONPOINT POLLUTION ABATEMENT PROGRAMS ON TWO FLORIDA BASINS1
Authors: Heatwole C. D. , Bottcher A. B. , Baldwin L. B.
Published: June 2007

ABSTRACT: A model was developed to evaluate the cost‐effectiveness of alternative “best management practice” (BMP) implementation schemes on two agricultural basins in Florida. The model selectively applies BMPs throughout the basin on a field by field basis, estimates the associated costs, and predicts the relative water quality improvement (reductions in nitrogen and phosphorus). The water quality model links field scale simulation (for detailed BMP evaluation) with basin delivery and attenuation functions to predict the basin‐wide effects of any combination of BMPs. Fifteen BMP scenarios were evaluated to aid in prioritizing BMPs for implementation in these basins. Applying the maximum level of BMPs is estimated to cost around $1.2 million (annually), while the four most cost‐effective BMPs would cost only one quarter as much, yet are projected to provide approximately 90 percent of the water quality improvement.
WATER CONSERVATION METHODS IN URBAN LANDSCAPE IRRIGATION: AN EXPLORATORY OVERVIEW1
Authors: Ferguson Bruce K.
Published: June 2007

ABSTRACT: The increasing use of irrigation for urban landscapes is causing new demands for efficient watering systems. Conservation techniques for irrigated agricultural fields cannot be applied to urban landscapes without amendment. This paper attempts to review methods of urban landscape water conservation in the context of the diversity and complexity of urban landscapes and the demands upon them for quality of the urban environment. A development's initial site layout and planting design fundamentally determine how much irrigation water will be required; the complexity and creativity inherent in urban design open a number of specific possibilities for reducing water demand. Irrigation hardware is then designed to deliver the required volume of water to the specified landscape efficiently by implementing a number of physical and operational principles. Maintenance of the finished development involves monitoring results and making adjustments as the plantings grow and develop. The potential for conserving urban irrigation water is large. Effective conservation need not compromise other qualities of the urban environment such as aesthetics, screening, or shade. Urban design can address both the kinds of landscapes people need, and minimal consumption of irrigation water.
STEADY‐STATE ANALYSIS OF INFILTRATION AND OVERLAND FLOW FOR SPATIALLY‐VARIED HILLSLOPES1
Authors: Hawkins R. H. , Cundy T. W.
Published: June 2007

ABSTRACT: An envelope of steady‐state surface runoff response for a hilislope is established in terms of the probability distribution and spatial arrangement of individual point infiltration capacities and the rainfall intensity. Minimum overland flow is shown to occur when point infiltration capacities are ordered with the highest at the slope bottom, while maximum overland flow occurs when the highest point capacities are at the top of the slope. Equations for envelope curves are developed for both continuous distributions and discretely sampled data; examples for each case are given. Use of the analysis as a rainfall‐runoff model is also discussed.
COMPUTATION OF UNSTEADY FLOWS IN THE ALABAMA RIVER1
Authors: Jeffcoat Hillary H. , Jennings Marshall E.
Published: June 2007

ABSTRACT: An application is described of the branch‐network flow model, BRANCH, to the upper Alabama River system in central Alabama. The model is used to simulate one‐dimensional unsteady flows and water surface elevations in approximately 60 river miles of the Alabama River system. Preliminary calibration was made using 72 hours of observed data. Simulated discharges are about 10 percent lower than observed discharges at higher discharge rates and computed flows lag observed flows by about 30 minutes.
OPTIMAL MANAGEMENT OF A REGIONAL AQUIFER IN EASTERN SAUDI ARABIA1
Authors: Yazicigil Hasan , Al‐Layla Rashid I. , de Jong Remy L.
Published: June 2007

ABSTRACT: This paper describes the formulation and application of a ground‐water hydraulic management model to determine the optimal development and operating policies of a regional aquifer in the Eastern Province of Saudi Arabia. The hydraulic response of the aquifer system is represented by a simulation model that is linked to an optimization management model using response functions. Yearly optimal ground‐water extraction rates over a planning horizon of 15 years are determined for four scenarios, each reflecting alternative ground‐water development policies. The results are presented in the form of tradeoff curves, relating drawdowns to optimal pumpage, which may enhance the decisionmaker's ability to select the best development policy from a set of alternatives. The results illustrate how various optimal management schemes can be devised to increase the total withdrawal from the aquifer while preventing excessive de‐watering.
REGIONAL RAINFALL INTENSITY‐DURATION‐FREQUENCY CURVES FOR PENNSYLVANIA1
Authors: Aron Gert , Wall David J. , White Elizabeth L. , Dunn Christopher N.
Published: June 2007

ABSTRACT: A statistical analysis of all available continuous hourly and 15‐minute duration rainfall records for Pennsylvania was performed to develop an updated procedure to estimate design storms. As a resuit of this study, Pennsylvania was divided into five homogeneous rainfall regions and a set of rainfall intensity‐duration curves developed for each region, for return periods of 1 to 100 years and durations ranging from 5 minutes to 24 hours. The PDT‐IDF curves were judged to be a better representation of Pennsylvania rainfall than the nationwide TP‐40 maps, particularly for storm events of 10‐years and lower return periods.

The average time distribution of 24‐hour storms in Pennsylvania was found to be well represented by the SCS Type II distribution. The Corps of Engineers SPS 24‐hour distribution was found to differ appreciably from both the SCS Type H and the Pennsylvania 24‐hour storm distribution. For storm durations between 15 and 90 minutes the standard Yarnell intensity‐duration curves closely resemble Pennsylvania storm distributions.
PROCESS‐ORIENTED ESTIMATION OF SUSPENDED SEDIMENT CONCENTRATION1
Authors: Irvine Kim Neil , Drake John J.
Published: June 2007

ABSTRACT:Least squares regression and ARIMA models were developed from suspended sediment data for the Ausable River, Southern Ontario, Canada. A poor correlation between discharge and suspended sediment concentration results from the dynamics of the physical system, including seasonality, antecedent conditions, and hysteresis. Regression model results were significantly improved by the division of the data set into seasons and the addition of simple. but physically meaningful variables. Misleading improvements obtained from the regression of sediment load and discharge are discussed. ARIMA models provided accurate forecasts of sediment concentration on a real‐time basis, but the rigorous data requirements limit their use in modeling suspended sediment concentrations in Canadian rivers.
BACTERIAL LEVELS IN CISTERN WATER SYSTEMS OF NORTHERN KENTUCKY1
Authors: Lye Dennis J.
Published: June 2007

ABSTRACT: In rural Northern Kentucky, rainwater is commonly collected from rooftops and stored in cement block cisterns as the sole source of drinking water. Although every cistern system is unique in some aspect of design, use, or maintenance, a bacterial survey of 30 rural Northern Kentucky cistern systems suggests that coliforms and heterotrophic bacteria are common to all types of cistern storage systems. An average of 600 coliforms/ml and 3.6 ± 105 heterotrophic bacteria/ml were detected in water samples from the bottoms of the cistern storage tanks. Bacterial levels in water delivered to household cold tap faucets were similar to the levels found in the storage tanks. When detected, fecal coliforms were recovered throughout the entire system including the household cold tap faucet. Current U.S. regulations for drinking water quality are discussed, with a suggestion that fecal coliform levels may be a more appropriate guideline for interpreting the water quality of individually maintained, nonchlorinated, nonpiped water supplies, such as cistern storage systems.
A COMPARISON OF METHODS FOR ESTIMATING LOW FLOW CHARACTERISTICS OF STREAMS1
Authors: Tasker Gary D.
Published: June 2007

ABSTRACT:Four methods for estimating the 7‐day, 10‐year and 7‐day, 20‐year low flows for streams are compared by the bootstrap method. The bootstrap method is a Monte Carlo technique in which random samples are drawn from an unspecified sampling distribution defined from observed data. The nonparametric nature of the bootstrap makes it suitable for comparing methods based on a flow series for which the true distribution is unknown. Results show that the two methods based on hypothetical distributions (Log‐Pearson III and Weibull) had lower mean square errors than did the Box‐Cox transformation method or the Log‐Boughton method which is based on a fit of plotting positions.
AGGREGATE MARGINAL RETURNS FROM WESTERN IRRIGATED AGRICULTURE1
Authors: Long Roger B.
Published: June 2007

ABSTRACT: Pressure is increasing in the western United States to reallocate water from irrigated agriculture to other competitive uses. Since water is normally allocated through water rights and not necessarily by the price system, the question of economic efficiency is a continual concern. Study results show that returns per acre‐foot of water used in western irrigation are quite high and are closely tied to the livestock industry. Returns per acre‐foot of water used for crops ranged from $60 to $1,500. When water was used to support livestock, returns per acre‐foot ranged from $100 to $600. Clearly, losses of water supply that reduced irrigation production could also lower farm income significantly. Estimated returns also show what alternative uses would have to pay for water under competitive market conditions. Production elasticities are also shown for various states.
INFILTRATION CAPACITY OF DISTURBED SOILS: TEMPORAL CHANGE AND LITHOLOGIC CONTROL1
Authors: Jorgensen David W. , Gardner Thomas W.
Published: June 2007

ABSTRACT: The hydrologic character and response of disturbed land is controlled, to a large degree, by soil infiltration characteristics. Reconstructed soils on surface mines (minesoils) of different age (1 to 4 years old) are used to investigate infiltration rates on disturbed landscapes. The data consist of soil/surface properties and runoff volumes fit to the Horton infiltration equation.

Infiltration rates on newly reclaimed minesoils are an order of magnitude lower than adjacent, undisturbed soil. Few significant correlations exist between soil/surface properties and infiltration parameters for newly reclaimed soils. However, the correlation between infiltration and minesoil characteristics increases with soil age. Multiple regressions are used to explore relationships between infiltration parameters and soil/surface properties for each soil age. Regression models of 30‐min infiltration volume and the steady‐state rate consistently include the percent silt and clay, slope, bulk density, and vegetation.

Mean infiltration volumes at different mines are equal in the first year following reclamation, but become significantly different with surface age. The magnitude of the increase is controlled by the soil texture, vegetation, slope, and bulk density. Soil characteristics are determined ultimately by the overburden lithology and its effect on mineralogy and grain size during physical redistribution of soil particles and initial weathering.
REUSE OF DOMESTIC WASTEWATER FOR IRRIGATION IN ARID ZONES: A CASE STUDY1
Authors: Oron Gideon , DeMalach Joel
Published: June 2007

ABSTRACT: The domestic sewage of the city of Beer‐Sheva, Israel, which is located in an arid region, is treated in a series of facultative ponds. The treated effluent is stored temporarily in an open surface earthen reservoir (about 0.5 ± 106 m3 in volume) and then used for irrigation. The effluent is applied via sprinkler and trickle irrigation systems. The main crops irrigated are cotton, wheat, alfalfa, and corn. Total cotton yield is over 5500 kg/ha, and the wheat grain yield is over 7500 kg/ha. The amount of effluent applied is about 6500 m3/ha for cotton (including preplant irrigation), and the wheat receives about 4500 m3/ha via irrigation and an additional 2000 m3/ha from precipitation. Due to the nutrient content in the effluent, the above yields are obtained without any additional fertilization.
A PRELIMINARY STUDY OF THE EFFECTS OF DRAINAGE AND HARVESTING ON WATER QUALITY IN OMBROTROPHIC BOGS NEAR SEPT‐ILES, QUEBEC1
Authors: Moore T. R.
Published: June 2007

ABSTRACT: Runoff and ground‐water samples were collected from four ombrotrophic bogs, representing undisturbed and drained/harvested conditions, at two‐week intervals during the summer of 1984. Analyses of samples for water quality parameters revealed significant (P < 0.05 level) increases in specific conductance, NH4+‐N, total dissolved P, Mg, K, and Na and a decrease in the E4:E6 ratio (suggesting increased proportions of humic acid) associated with drainage. There were no significant changes in dissolved organic carbon, Ca concentrations, or pH. Comparison of samples collected before, during, and after ditching showed increases in the dissolved organic carbon, NH4+‐N, total dissolved P, K, and Na and a decrease in the E4:E6 ratio, but these changes were short lived; water quality returned to preditching values after about a week. The observed changes in water quality are small, probably because the peat is very acid (pH 3.0 to 4.5).
OVERVIEW OF LANDFILL BOTTOM LINER HYDRAULICS1
Authors: Demetracopoulos Alexander C.
Published: June 2007

ABSTRACT: Landfill bottom liners are important elements in the analysis and design of solid waste disposal facilities. This study presents an overview of several models, describing the flow over and through liners. The examined models are compared against data from a laboratory investigation. A quasi‐steady state (QSS) and a transient (TS) model yield the most complete description of linear hydraulics, and allow for estimation of the system's collection efficiency. The TS model performed slightly better than the QSS model, although the latter has the advantage of simplicity. The hydraulic conductivities of the liner and the drainage layer and the leachate accretion rates are parameters whose magnitudes must be known with relative accuracy for good evaluation of system performance.
MULTIVARIATE NONPARAMETRIC TESTS FOR TREND IN WATER QUALITY1
Authors: Lettenmaier Dennis P.
Published: June 2007

ABSTRACT: National and state fixed station stream quality monitoring networks have now been in existence for over ten years. The resulting data bases provide opportunities and challenges for statistical trend assessment. Although nonparametric tests have been developed that are well suited to such problems, the interpretation of variations in trend significance between seasons and variables remains a problem. One recently developed test is based on the sum of Mann‐Kendall statistics over seasons or variables, with the test statistic variance computed as the sum of the covariances of the individual Mann‐Kendall statistics. In this method, up‐ and downtrends can cancel, giving an overall indication of no trend. A related test which is sensitive to trend regardless of direction has been shown to behave poorly for typical stream quality record lengths. An alternative formulation which is sensitive to up‐ and downtrends and has power approaching that of the covariance sum method, is described. In addition, a variation of a contrast test for discriminating trend directions and magnitudes among variables or seasons where correlation between seasons or variables is present is described, and tests of its performance reported.
TECHNOLOGY, INSTITUTIONS, AND SOCIAL GOALS1
Authors: Viessman Warren
Published: June 2007

ABSTRACT: The cries of pending water crises are usually cast in terms of water availability and/or water quality. Unfortunately, the real factors underlying a perceived crisis are often overlooked and the solutions prescribed are fax from optimal when measured in either economic or social terms. Today's technology outstrips its implementation, yesterday's solutions are imposed on a new breed of problems, and a static game is being played in a dynamic world. There is a need for the application of innovative and revolutionary tactics, for modernizing institutions, and for educating technologists and decision makers alike in the art of communicating their views and skills. This is the challenge. If it is met, some predicted crises will not materialize, and many others will be diminished in scale. An exciting opportunity exists to extend the boundaries of a new era in water management.
IDENTIFYING CRITICAL ISSUES IN RECREATION PLANNING AND MANAGEMENT: IMPROVING THE MANAGEMENT‐RESEARCH PARTNERSHIP1
Authors: Schomaker John H. , Lime David W.
Published: June 2007

ABSTRACT:The “nominal group” process is a proven technique to systematically arrive at a consensus about critical information needs in recreation planning and management. Using this process, 41 managers who attended a 1983 conference on river management identified 114 specific information needs grouped under 11 general questions. Clearly, some concerns of administrators are researchable; many are not.
EMPIRICAL MODELS FOR TROPHIC STATE IN SOUTHEASTERN U.S. LAKES AND RESERVOIRS1
Authors: Reckhow Kenneth H.
Published: June 2007

ABSTRACT: A cross‐sectional data set of 80 lakes and reservoirs in nine southeastern states was examined to specify and parameterize trophic state relationships. The relationships fitted are based on measurements of several limnological variables taken over the course of a growing season or year in each of the lakes. The trophic state models relate phosphorus and nitrogen loading to inlake phosphorus and nitrogen concentrations, which in turn are related to maximum chlorophyll level, Secchi disk depth, dominant algal species, and hypolimnetic dissolved oxygen status. Due to the empirical nature of the study, causal conclusions are limited; rather, the models are most useful for prediction of average growing season conditions related to trophic state.
RESIDENTIAL WATER DEMAND IN METRO MANILA1
Authors: Palencia Lamberto C.
Published: June 2007

ABSTRACT: An econometric demand function is estimated for residential water use in Metropolitan Manila. Regression results using annual time series data from 1970 to 1981 show that residential water consumption responds to changes in economic variables. Residential demand showed an income (household) elasticity of 0.542 and a combined price elasticity of ‐0.287. Implications for planning and management are discussed.
DESIGNATION OF WETLANDS BY WEIGHTED AVERAGES OF VEGETATION DATA: A PRELIMINARY EVALUATION1
Authors: Wentworth Thomas R. , Johnson George P. , Kologiski Russell L.
Published: June 2007

ABSTRACT: Weighted averages (WA) was investigated as a vegetation‐based method for wetland designation, to be used in conjunction with the wetland indicator status of plants from Wetland Plants of the United States of America 1986 (Reed, 1986). Ecological indices were assigned to indicator groups and were used to compute weighted averages for quantitative data obtained from four studies of wetland vegetation conducted in various regions of the United States. Weighted averages of vegetation data proved to be a useful tool for assessing wetland status of the vegetation types included in our study: (1) rankings of vegetation stands or types by WA correlated well with their positions on environmental moisture gradients; and (2) the results of WA could be used, together with a wetland/upland break‐point, to designate vegetation types as wetland or upland in a way that agreed well, in three of the four studies, with an alternative classification of wetland habitats. The variation of weighted averages among the sampling units representing a vegetation type was generally small relative to the range of ecological indices assigned. However, designations based on weighted average scores close to the break‐point should be considered provisional and must be verified with supplementary data on soils and hydrology.
PRIVATIZING THE GROUND WATER RESOURCE: INDIVIDUAL USE AND ALTERNATIVE SPECIFICATIONS1
Authors: Fractor David T.
Published: June 2007

ABSTRACT: While most inquiries into improving the efficiency of ground water allocation have focused upon various schemes involving centralized management, recently the focus has shifted towards exploring private property solutions to these problems. However, most of these studies, when modeling ground water use, have equated behavior under private property to that under common property conditions. This leads to the possibly mistaken conclusion that private property rights do not promote more efficient ground water use, because these models assume that producers ignore the future effects of current pumping. This paper attempts to correct this deficiency by formally modeling ground water use under common property, central management, and private property scenarios. Moreover, there are many ways that property rights can be defined over ground water, some establishing more exclusivity over the resource than others. Four specifications of property rights are analyzed for their likely effects on allocative efficiency: full stock‐flow, partial stock‐flow, limited stock‐flow, and pure flow rights.
IRRIGATION WATER DELIVERY SYSTEM OPERATION VIA AGGREGATE STATE DYNAMIC PROGRAMMING1
Authors: Houghtalen Robert J. , Loftis Jim C.
Published: June 2007

ABSTRACT: A modified dynamic programming (DP) approach that is called aggregate state dynamic programming (ASDP) is presented to optimally operate irrigation water delivery systems. ASDP can be applied to multiple reservoir systems without encountering dimensionality problems. In addition, the random nature of water supply and consumptive crop demands can be incorporated into the technique. A case study is presented to display the application of ASDP. Using a sum‐of‐squared shortages objective, ASDP out performs a traditional separation technique and approaches the theoretical (ideal) optimum. Problem settings that are conducive to the use of ASDP and limitations of the technique are presented.
FISH TUMORS AND ECOLOGICAL SURVEILLANCE: A CAUTIONARY EXAMPLE FROM PORT PHILLIP BAY1
Authors: Hard Gordon C.
Published: June 2007

ABSTRACT: Interest in the development of strategies using faunal populations for monitoring chemical contamination of the environment was promoted, in part, by earlier investigations of skin lesions that were mistakenly diagnosed as epidermal papillomas in flatfish from Pacific coastal waters of the northern hemisphere. A survey aimed at exploring chemical pollution effects was also undertaken in the southern hemisphere in Port Phillip Bay, Australia, where over 15,000 fish, involving ten mainly bottom‐feeding species, were sampled. Only two cases of true neoplasia (both in the sand flathead) were found, but there was a high prevalence of cancer‐like growths in certain species of leatherjacket and a low prevalence in spiky globe fish. Morphological analysis proved these to be subacute inflammatory or chronic granulomatous reactions possibly due to parasitic infestation. These findings were discussed in relation to recent work that shows the epidermal papilloma to be a pseudotumor, and the propensity for fish to develop exuberant inflammatory responses to exogenous stimuli which mimic neoplasia.
ESTIMATES OF MEAN CHLOROPHYLL‐a CONCENTRATION: PRECISION, ACCURACY, AND SAMPLING DESIGN1
Authors: Marshall C. Tara. , Morin Antoine , Peters Robert H.
Published: June 2007

ABSTRACT:Data from 56 north‐temperate lakes and reservoirs are used to develop models predicting temporal variance as a function of the mean chlorophyll‐a concentration. Trophy, as estimated by mean chlorophyll‐a concentration, is shown to have little effect on the sampling effort required to achieve a pre‐determined level of precision for lakes sampled year‐round. Collecting ten observations results in a coefficient of variation that averaged 20 percent; collecting more than ten observations yields increasingly marginal improvements in precision. The same guidelines apply to mesotrophic or eutrophic lakes sampled in the summer, whereas oligotrophic lakes sampled in the summer require fewer observations to achieve the same level of precision. The bias resulting from collecting too few observations is minimized if five or more observations are collected.
DETERMINATION OF UNGAGED TRIBUTARY FLOWS AND INTERSEGMENTAL RESERVOIR FLOWS USING SPREADSHEET SOFTWARE1
Authors: Dymond R. L. , McDonnell A. J.
Published: June 2007

ABSTRACT: Spreadsheet software was utilized on two related large scale trial and error problems. Gaged streamflow data and known reservoir volumes were used to construct a daily continuity balance in order to estimate the daily mean flows from ungaged portions of a study watershed over one year. Watershed yield coefficients were determined for two diverse types of watersheds with and without significant ground water contribution. Subsequently, a spreadsheet template was devised to ensure than an EPA supported water quality model, WASP, would successfully model the actual segmental volumes of a flood control reservoir. Inlet, outlet, and intersegmental advective flows were determined on a two week average basis using a continuity balance, segmental routing, and known segmental volumes. The protocols described relate the use of microcomputers to the resolution of hydraulic and hydrologic problems requiring iterative solutions.
A NONTRADITIONAL METHODOLOGY FOR FLOOD STAGE‐DAMAGE CALCULATIONS1
Authors: Das Sujit , Lee Russell
Published: June 2007

ABSTRACT: This paper presents a new methodology to calculate economic losses from hypothetical, extreme flood events, such as the Probable Maximum Flood. The methodology uses economic data compiled from already‐available secondary sources, such as U.S. Census data on magnetic tapes, utilizing microcomputer and other electronic media. Estimates of land elevations are obtained from topographic maps, and flood elevations axe estimated using, for example, a dam breach and flood routing (DAMBRK) model (Fread, 1984). The calculations are performed at a disaggregate spatial scale, by various land use and industrial classification categories. The basic areal units are city blocks (for urbanized areas), enumeration districts, and Census tracts. Depth‐damage functions, which provide an estimate of damages as a proportion of the existing value of the structure, are estimated statistically. Computer software (called DAMAGE) is used to combine the economic, flood elevation, and depth‐damage information to compute economic losses for different possible flood stages and for different inflow events. Two case studies are presented as illustrations of the method.
ASSESSING THE THREAT TO LIFE FROM DAM FAILURE1
Authors: Brown Curtis A. , Graham Wayne J.
Published: June 2007

ABSTRACT: To facilitate decisions regarding the need for modification of potentially unsafe dams, the U.S. Bureau of Reclamation developed procedures for assessing the threat to human lives posed by the failure of individual dams. The procedures provide a conceptual model of the variables influencing the loss of life from dam failure and a method for predicting loss of life based on the size of the population at risk from failure and the amount of warning time available for that population. The prediction equations are based on an analysis of 24 dam failures and major flash floods occurring since 1950. Adjustments to the predictions to reflect special local conditions are also discussed.
ASSESSMENT OF NUTRIENT EFFECTS AND NUTRIENT LIMITATION IN LAKE OKEECHOBEE1
Authors: Schelske Claire L.
Published: June 2007

ABSTRACT: Lake Okeechobee, the third largest lake in the United States, is a shallow, mixing basin with annual total phosphorus concentrations ranging from 50–100 μg P/L. Data, mainly from unpublished agency reports, are analyzed to determine if nutrients limit phytoplankton, to describe spatial and temporal variability in trophic state parameters, and to evaluate conclusions obtained from empirical trophic state models. Algal bioassay experiments that have been used to assess nutrient limitation have produced equivocal results. However, seasonal minima in orthophosphorus and inorganic nitrogen indicate that both nutrients may be limiting seasonally. Strong, but reverse north‐south gradients and large seasonal changes in phosphorus and nitrogen concentrations, show that empirical models based on annual phosphorus loadings or concentrations are not adequate to predict chlorophyll concentrations or other trophic state variables. Spatially‐segmented, multi‐class phytoplankton‐nutrient models of seasonal phytoplankton responses that are coupled with hydrodynamic models may provide predictability in assessing effects of changing nutrient loads on phytoplankton composition and standing crop. Successful modeling efforts of responses to nutrients also must deal with resuspended and benthic algae, periphyton, and emergent and submergent aquatic plants that must play important trophic roles in some of the lake basin.
LEAD AND CADMIUM ASSOCIATED WITH SALTWATER INTRUSION IN A NEW JERSEY AQUIFER SYSTEM1
Authors: Pucci Amleto A. , Harriman Douglas A. , Ervin Elisabeth M. , Bratton Lisa , Gordon Alison
Published: June 2007

ABSTRACT: The U.S. Geological Survey collected ground‐water samples from the upper and middle aquifers of the Potomac‐Raritan‐Magothy aquifer system in a 400‐square‐mile area of New Jersey from 1984 through 1986. Concentrations of lead were greater than the U.S. Environmental Protection Agency maximum contaminant level (MCL) of 50 micrograms per liter in water from 16 of 239 wells. The cencentrations of cadmium were greater than the MCL of 10 micrograms per liter in water from 10 to 241 wells. One‐half of the wells that exceeded the lead MCL were in known areas of saltwater intrusion, as were all 10 wells that exceeded the cadmium MCL. The association of elevated concentrations of these metals with elevated concentrations of chloride indicates a mochanism related to saltwater intrusion.
INTERPLAY BETWEEN PARAMETER UNCERTAINTY AND MODEL AGGREGATION ERROR1
Authors: Warwick John J.
Published: June 2007

ABSTRACTS: Modeling error can be divided into two basic components: use of an incorrect model and input parameter uncertainty. Incorrect model usage can be further subdivided into inappropriate model selection and inherent modeling error due to process aggregation. Total modeling error is a culmination of these various modeling error components, with overall optimization requiring reductions in all.

A technique, utilizing Monte Carlo analysis, is employed to investigate the relative importance of input parameter uncertainty versus process aggregation error. An expanded form of the Streeter‐Phelps dissolved oxygen equation is used to demonstrate the application of this technique. A variety of scenarios are analyzed to illustrate the relative obfuscation of each modeling error component. Under certain circumstances an aggregated model performs better than a more complex model, which perfectly simulates the real system. Alternately, process aggregation error dominates total modeling error for other situations. The ability to differentiate modeling error impact is a function of the desired or imposed model performance level (accuracy tolerance).
GROUNDWATER CONTAMINATION BY NEMATICIDES: INFLUENCE OF RECHARGE TIMING UNDER PINEAPPLE CROP1
Authors: Oki Delwyn S. , Giambelluca Thomas W.
Published: June 2007

ABSTRACT: Toxic organic compounds, such as DBCP, EDB, and c TCP, that are associated with pineapple cultivation in Hawaii have been discovered in drinking water wells on Oahu. In order to reach and contaminate the Pearl Harbor aquifer, pesticides must be transported quickly downward away from the soil surface prior to complete volatilization, degradation, or adsorption of residuals. This paper assesses the role of pesticide application timing relative to subsequent rainfall‐induced recharge events in determining the amount and extent of chemical leaching from the soil. A water balance model for a pineapple crop is developed to estimate the time series of recharge from two fields for which soil contamination profiles are available. In general, the amounts of DBCP, EDB, and TCP found in the soil profiles of the two fields are consistent with expectations of leaching based on an analysis of the recharge time series. The results indicate that recharge during and immediately following the application of pesticides is important in determining whether groundwater contamination will result.
DEVELOPMENT OF A BACTERIAL TRANSPORT MODEL FOR COARSE SOILS1
Authors: Peterson Thomas C. , Ward Robert C.
Published: June 2007

ABSTRACT: A bacterial transport model, developed to analyze bacterial translocation in coarse‐grained soils, is presented. The complex governing equation is presented first, followed by analyses of each of the major processes influencing bacterial transport. These analyses suggest simplification of the governing equation is feasible when input data on specific processes are limited or unavailable. Model parameters, including bacterial die‐off, bacterial distribution, input bacterial concentration, and saturated hydraulic conductivity, were randomly generated using a procedure known to produce either a normal or log‐normal distribution of random numbers. Monte Carlo simulations were completed, and the resulting output was used to generate cumulative frequency distributions showing the probability of bacterial transport beyond various soil depths. Results from these simulations indicate that bacteria have a high probability of traveling through coarse‐grained soils when low clay content and soil water temperatures limit bacterial retention and die‐off.
UNCERTAINTY ANALYSIS OF RUNOFF ESTIMATES FROM A RUNOFF CONTOUR MAP1
Authors: Rochelle Barry P , Stevens Donald L. , Church M. Robbins.
Published: June 2007

ABSTRACT: The U.S. Environmental Protection Agency (EPA) in cooperation with the U.S. Geological Survey (USGS) conducted an analysis to quantify the uncertainty associated with interpolating runoff to specific sites using a runoff contour map. We interpolated runoff to 93 gaged watersheds from a runoff contour map using (1) hand interpolation to the watershed outlet, (2) a computer interpolation to the watershed outlet, and (3) hand interpolation to the watershed centroid. We compared the interpolated values to the actual gaged values and found that there was a bias in the average interpolated value for runoff estimated at basin outlets, with interpolated values being less than the actual. We found no significant difference between the hand interpolation method and the computer interpolation method except that the computer method tended to have higher variability due to factors inherent to the software used. There were no strong spatial correlations or regional patterns in the runoff interpolations, which indicates that there are no regional biases introduced in the development of the contour map.

We determined that we could estimate runoff, on the average, within approximately 8.9 cm (3.5 in; 15 percent) of the measured value using the three methods. The results of this work indicate that runoff contour maps can he used in regional studies to estimate runoff to ungaged systems with quantifiable uncertainty.
HYDROLOGIC UNCERTAINTY MEASURE AND NETWORK DESIGN1
Authors: Husain Tahir
Published: June 2007

ABSTRACT: This paper presents a simple methodology, using the entropy concept, to estimate regional hydro logic uncertainty and information at both gaged and ungaged grids in a basin. The methodology described in this paper is applicable for (a) the selection of the optimum station from a dense network, using maximization of information transmission criteria, and (b) expansion of a network using data from an existing sparse network by means of the information interpolation concept and identification of the zones from minimum hydrologic information. The computation of single and joint entropy terms used in the above two cases depends upon single and multivariable probability density functions. In this paper, these terms are derived for the gamma distribution.

The derived formulation for optimum hydrologic network design was tested using the data from a network of 29 rain gages on Sleeper River Experimental Watershed. For the purpose of network reduction, the watershed was divided into three subregions, and the optimum stations and their locations in each subregion were identified. To apply the network expansion methodology, only the network consisting of 13 stations was used, and feasible triangular elements were formed by joining the stations. Hydrologic information was calculated at various points on the line segments, and critical information zones were identified by plotting information contours. The entropy concept used in this paper, although derived for single and bivaviate gamma distribution, is general in type and can easily be modified for other distributions by a simple variable transformation criterion.
AN AUTO‐CAD‐BASED WATERSHED INFORMATION SYSTEM FOR THE HYDROLOGIC MODEL HEC‐11
Authors: Cline T J. , Molinas A. , Julien P. Y.
Published: June 2007

ABSTRACT: A micro computer based Watershed Information System (W.LS.) is developed to assist in the preparation of input files for the hydrologic simulation model HEC‐1. This system consists of three phases. Phase I utilizes the capabilities of AutoCAD version 9 and three programs, BASINS, PLANES, and CHANNELS, to extract, organize, and display watershed data. Phase II uses the program CN to calculate some HEC‐1 parameter values. Phase II utilizes the program HECUPDATE to create HEC‐1 input files. The system input includes topographic, soils, land use, watershed geometry data, and a skeletal HEC‐1 input file. Output from the system includes a summary User Reference File, a Soils File, a Land Use File, a Watershed Geometry File, a Curve Number File, and a HEC‐1 input file, which is ready to run. The W.I.S. has been applied to Macks Creek Watershed in southwest Idaho.