WATER-SURFACE PROFILES WITHOUT ENERGY LOSS COEFFICIENTS1

ABSTRACT: This paper describes a new method of computing water-surface profiles, which does not require the assumption of hydrostatic pressure or of roughness coefficients. The method is based upon distributing entropy production values along a channel as uniformly as boundary conditions permit. The method requires a discharge capacity rating at a channel cross-section within the limits of the reach of the channel. A new theoretical relationship between the kinetic and momentum coefficients for the velocity profile is used, together with a dynamic programming technique for optimal distribution of energy losses along the channel. A computer model was developed and was used to verify the methodology for flood flow and channel data at four locations.     

OPTIMIZING FLOOD CONTROL ALLOCATION FOR A MULTIPURPOSE RESERVOIR1

ABSTRACT. In the last decade much research has been devoted to applying the systems analysis approach to water resources problems. A popular research goal has been determination of the “best” method of operating a multipurpose reservoir. The goal of this study was to derive the economically optimum flood control diagram for a multipurpose reservoir by systems analysis. The technique employed to optimize the flood control diagram was programmed so that the optimization process could be applied to other multipurpose reservoirs. Two computer programs developed at the U.S. Army Corps of Engineers' Hydrologic Engineering Center were utilized with modifications to simulate the operation of Folsom Reservoir in central California. Economic analyses were incorporated along with an optimization technique into the reservoir operations program; and the resultant program was capable of routing a sequence of monthly reservoir inflows, computing benefits for various flood control diagrams (as dictated by the optimization procedure), and selecting the economically optimum flood control diagram. The univariate gradient technique was the optimization procedure employed. The two computer programs are on file at the Hydrologic Engineering Center in Davis, California.     

OWNERSHIP OF INTERNATIONAL WATERS1

When the boundaries of nations cover the same watershed, who owns the border water? The answer to that question is the premise of this paper. A discussion of international water law is given. Implementing the law is portrayed in an outline for (1) administration, (2) a procedure for data collecting, and (3) a computer system for data processing and determining ownership of water for each country. Special situations are considered, and a conclusion developed. After international law between two countries has been established, determining the ownership of boundary water is both feasible and practical. A computer method is shown whereby this is accomplished. The unique aspect of the method is the fact that cooperation and mutual esteem between individuals of both countries are necessary in order to obtain results.     

AQUIFER PARAMETERS FROM CONSTANT DRAWDOWN NONSTEADY-LEAKY TYPE CURVES1

ABSTRACT: A drain function and set of type curves were defined for the mathematical solution that represents one-dimensional flow under nonsteady conditions in a leaky aquifer for the constant drawdown boundary condition. A match point procedure was developed for determining the aquifer parameters transmissivity, storage coefficient, and leakance based on the drain function and type curves. Use of the procedure is illustrated by an example that utilizes simulated aquifer drawdowns and flowrate data. The drain function and type curves developed in this investigation include the effects of leakage for the constant drawdown boundary condition, which is not included in the existing drain function and type curve found in the literature. Thus, a new set of type curves was developed that can be used to analyze drawdowns for one-dimensional flow in a leaky aquifer with constant drawdown at a line sink. Applications would include flow to a canal or river, drainage of agricultural lands, and dewatering associated with strip mining operations.     

COMBINED SURFACE WATER-GROUNDWATER ANALYSIS OF HYDROLOGICAL SYSTEMS WITH THE AID OF THE HYBRID COMPUTER1

The solution with the aid of the hybrid computer of the partial and total differential equations for an integrated surface water groundwater system is described. A versatile computing technique has been developed to make a rapid and accurate study of the groundwater response due to varying inputs (deep percolation) or outputs (evapotranspiration) from the groundwater system. Spatial variations in basic vegetation phenomena, such as pattern, and hydrological parameters, are represented by means of a grid network which also allows the input of variable boundary conditions. The model is applied to an area in Columbia, South America which is subject to high water-table conditions. Various reclamation schemes and management practices under conditions of irrigated agriculture are assessed.     

A LUMPED APPROACH TO THE INVERSE PROBLEM IN GROUND WATER HYDROLOGY1

ABSTRACT: A solution procedure to solve the inverse problem in ground water, based on lumped approach, has been proposed. The method has the following advantages: 1) exact determination of the boundary conditions and the physical laws of flow through porous media is not required; 2) all errors of approximation in describing the boundary conditions, physical laws, and the aquifer properties are lumped into the surrogate parameters; and 3) the same mathematical model can be employed both in the identification process and in the subsequent management studies. The optimal values of the surrogate parameters are found by using a multidimensional unconstrained optimization code devised by Powell. The solution procedure and the convergence characteristics of the proposed algorithm have been illustrated by two hypothetical problems.     

Land classification used to select abandoned hazardous waste study sites

The biological effects of hazardous substances in the environment are influenced by climate, physiography, and biota. These factors interact to determine the transport and fate of chemicals, but are difficult to model accurately except for small areas with a large data base. The requirement for a large data base may be reduced locally if the regional influences of these factors were predetermined from existing data. Knowledge of the regional factors would also relax the restriction to considering only small areas. This paper advocates consideration of regional characteristics of the environment in the early stages of waste management strategy development. It presents as an example a procedure for selecting study sites from candidate-abandoned hazardous waste dumpsites in the southeastern United States. It uses small-scale maps of low resolution from the National Atlas to delineate the boundaries and to determine the environmental characteristics that prevail over units of land within the region. A computer map-overlay and graphic approach is used to facilitate the grouping of land types. Abandoned hazardous waste dumpsites found within land types that best represent the region are surveyed for selecting a study site. It is expected that environmental impact data obtained from a representative site would be useful for predicting impact potentials in similar remotely located areas within the same general region.     

Evaluating the Illinois Stream Valley Segment Model as an Effective Management Tool

Stream habitat assessments are conducted to evaluate biological potential, determine anthropogenic impacts, and guide restoration projects. Utilizing these procedures, managers must first select a representative stream reach, which is typically selected based on several criteria. To develop a consistent and unbiased procedure for choosing sampling locations, the Illinois Department of Natural Resources and the Illinois Natural History Survey have proposed a technique by which watersheds are divided into homogeneous stream segments called valley segments. Valley segments are determined by GIS parameters including surficial geology, predicted flow, slope, and drainage area. To date, no research has been conducted to determine if the stream habitat within a valley segment is homogeneous and if different valley segments have varying habitat variables. Two abutting valley segments were randomly selected within 13 streams in the Embarras River watershed, located in east-central Illinois. One hundred meter reaches were randomly selected within each valley segment, and a transect method was used to quantify habitat characteristics of the stream channel. Habitat variables for each stream were combined through a principal components analysis (PCA) to measure environmental variation between abutting valley segments. A multivariate analysis of variance (MANOVA) was performed on PCA axes 1–3. The majority of abutting valley segments were significantly different from each other indicating that habitat variability within each valley segment was less than variability between valley segments (5.37 ≤ F ≤ 245.13; P ≤ 0.002). This comparison supports the use of the valley segment model as an effective management tool for identifying representative sampling locations and extrapolating reach-specific information.     

A PLANNING METHOD FOR EVALUATING DOWNSTREAM EFFECTS OF DETENTION BASINS1

While storm water detention basins are widely used for controlling increases in peak discharges that result from urbanization, recent research has indicated that under certain circumstances detention storage can actually cause increases in peak discharge rates. Because of the potential for detrimental downstream effects, storm water management policies often require downstream effects to be evaluated. Such evaluation requires the design engineer to collect additional topographic and land use data and make costly hydrologic analyses. Thus, a method, which is easy to apply and which would indicate whether or not a detailed hydrologic analysis of downstream impacts is necessary, should decrease the average cost of storm water management designs. A planning method that does not require either a large data base or a computer is presented. The time co-ordinates of runoff hydrographs are estimated using the time-of-concentration and the SCS runoff curve number; the discharge coordinates are estimated using a simple peak discharge equation. While the planning method does not require a detailed design of the detention basin, it does provide a reasonably accurate procedure for evaluating whether or not the installation of a detention basin will cause adverse downstream flooding.     

SURFACE AREA CORRECTIONS APPLIED TO A RESOURCE MAP1

ABSTRACT: Generally a difference exists between the horizontal planar area of a watershed as measured on a map and the actual surface area. A technique is presented, utilizing a topographic map, for computing the difference in the two areas as well as yielding a prediction of the actual surface area. Spatial variations in the magnitude of the difference in the two areas for small local sites over the watershed are displayed on computer generated maps. The technique is also used to adjust various inventory variables on maps, such as vegetation density, to reflect actual surface coverage. This allows estimates to be made of the difference in using corrected versus uncorrected area related parameters in mathematical functions describing processes occurring in the atmosphere-surface boundary layer.     

The application of charging schemes for the management of water pollution

This paper examines lessons from the experience in the use of charges for water resource management, considers how charges have been used in Europe, and how a new charging system could be developed. It focuses particularly on the case for pollution charges, or charges for using a river for the disposal of waste. The paper falls into four sections. The first reviews briefly the case for pollution charges, both theoretical and practical, and shows how they can complement regulatory systems. The experience of pollution charging schemes in the Netherlands, Germany and France, where charges have been used as a major mechanism for environmental and water resource management for upwards of 10 years are examined. The basis for charge schemes, their effectiveness as policy instruments and the institutional framework within which they operate are discussed. The paper addresses some questions which are central to the definition and development of charge schemes- the objectives, the problems and constraints. A case study is used to establish the feasibility of introducing emission charges for water resource management. How the charge could be designed and administered and how the charge level could be set is also described. Finally, some broad recommendations on the effectiveness and issues associated with charge schemes are presented.     

ADVANCES IN THE BOUNDARY INTEGRAL EQUATION METHOD IN SUBSURFACE FLOW1

ABSTRACT: This paper explores some of the advances of the boundary element method, as applied to ground-water problems, during the last five years. Although the method is still somewhat limited compared to solution by finite elements, the range of solutions has increased considerably. Diffusion and advection-diffusion solutions are done efficiently. These include the incorporation of inhomogeneity, anisotropy, and nonlinear diffusion. The difficult problem of stream-aquifer interaction is an important application as it is much easier to follow a free surface with its multiple configurations. The application must be able to cycle between ground-water connection and disconnection with the stream and include seepage surfaces. Flow in fractured media is a natural application where the flow in fractures can usually be treated without a computational exception in spite of extremely high aspect ratios. The case of seawater intrusion forms a type of free surface problem and thus is a case for which the method has special advantages. For these and other applications the boundary element method provides an inexpensive technique for calculation where the data preparation and setup time is minimal. In most of these cases, programs can and have been written on microcomputers.     

COOPERATIVE MODELING: BUILDING BRIDGES BETWEEN SCIENCE AND THE PUBLIC1

As freshwater resources become more scarce and water management becomes more contentious, new planning approaches are essential to maintain ecologic, economic, and social stability. One technique involves cooperative modeling in which scientists and stakeholders work together to develop a computer simulation model to assist in planning efforts. In the Middle Rio Grande region of New Mexico, where water management is hotly debated, a stakeholder team used a system dynamics approach to create a computer simulation model to facilitate producing a regional plan. While the model itself continues to be valuable, the process for creating the model was also valuable in helping stakeholders jointly develop understanding of and approaches to addressing complex issues. In this paper, the authors document results from post‐project interviews designed to identify strengths and weaknesses of cooperative modeling; to determine if and how the model facilitated the planning process; and to solicit advice for others considering model aided planning. Modeling team members revealed that cooperative modeling did facilitate water planning. Interviewees suggested that other groups try to reach consensus on a guiding vision or philosophy for their project and recognize that cooperative modeling is time intensive. The authors also note that using cooperative modeling as a tool to build bridges between science and the public requires consistent communication about both the process and the product.     

Resampling methods for evaluating classification accuracy of wildlife habitat models

Predictive models of wildlife-habitat relationships often have been developed without being tested The apparent classification accuracy of such models can be optimistically biased and misleading. Data resampling methods exist that yield a more realistic estimate of model classification accuracy These methods are simple and require no new sample data. We illustrate these methods (cross-validation, jackknife resampling, and bootstrap resampling) with computer simulation to demonstrate the increase in precision of the estimate. The bootstrap method is then applied to field data as a technique for model comparison We recommend that biologists use some resampling procedure to evaluate wildlife habitat models prior to field evaluation.     

INTEGRATING GEOGRAPHIC INFORMATION SYSTEMS IN GROUND-WATER APPLICATIONS USING NUMERICAL MODELING TECHNIQUES1

ABSTRACT: The Sand and Gravel Aquifer is the sole source of potable water in Escambia County, Florida. In order to better understand the hydraulics of the aquifer, a numerical computer model of the aquifer was developed. The model applied a finite element technique which allowed for density-dependent transport and flow in three dimensions. The modeling technique was integrated with GIS to develop a system for optimal management of the resource. The GIS was the primary tool in the development of the model grid, as well as being the integral component in the modeling procedure. Multiple model grids were developed for simulating regional flow and local flow/transport phenomena. The model grids were generated by the GIS where nodal and element sequencing were recorded. The grid topology was stored in the GIS with the element numbers, node numbers, and the related hydrogeologic attributes. The Triangulated Irregular Network (TIN) module was used for transferring interpolated value between GIS coverages. TIN allowed a fit of the model grid to the physical dimensions of the aquifer and for interpolating boundary values for telescopically refined grids. Calculations between TIN surfaces provided the residuals of the dependent variable from observed TIN surfaces. Model calibration was conducted within the GIS environment through a combination of visual and relational querying. The GIS provided an integrated environment which facilitated model analyses and data storage and retrieval.     

A METHOD FOR OBTAINING SLOPE INFORMATION FOR HYDROLOGIC MODELS1

: A method is described for obtaining surface slope information for analysis with other land resource and water quality data in hydrologic models of nonpoint sources of water pollution. The method described requires a point sampling scheme, topographic maps, and a coordinate digitizer. Sample point elevation, slope direction, and slope magnitude are calculated from locations of the sample point and the nearest upper and lower contour lines. Details of the data collection methodology and associated problems are discussed.     

A DIGITAL OVERLAY TECHNIQUE FOR EVALUATION OF POTENTIAL INFILTRATION AND RECHARGE1

ABSTRACT: A common problem encountered during regional planning and development of ground water dependent communities is the difficulty in deciding which areas should be preserved for aquifer recharge purposes. This paper describes the development and application of a digital overlay technique for objective evaluation and ranking of potential infiltration and potential recharge areas. Equations are developed which relate the hydrologic parameters pertaining to infiltration and recharge in a surface aquifer-confined aquifer system. These equations make use of discrete data, yet by application in a digital overlay technique results are obtained in the form of spatial distributions in order for regional trends and conditions to be examined. An application of this procedure to the 551,000 acre region of central Florida, known as the Green Swamp, is discussed. The results are presented in the form of computer generated maps which identify and rank areas of potential recharge to the aquifer system.     

UTILIZATION OF A GEOGRAPHIC INFORMATION SYSTEM TO IDENTIFY THE PRIMARY AQUIFER PROVIDING GROUND WATER TO INDWIDUAL WELLS IN EASTERN ARKANSAS1

ABSTRACT: A Geographic Information System (GIS) was used to develop an automated procedure for identifying the primary aquifers supplying ground water to individual wells in eastern Arkansas. As mandated by state law, water-use data are reported by ground-water withdrawers annually to the Arkansas Soil and Water Conservation Commission, and stored in the Arkansas Site-Specific Water-Use Data System provided and supported by the U.S. Geological Survey. Although most withdrawers are able to provide the amount of water withdrawn and the depth of their wells, very few are able to provide the name of the aquifer from which they withdraw water. GIS software was used to develop an automated procedure for identifying the primary aquifers supplying ground water to individual wells in eastern Arkansas. The software was used to generate a spatial representation of the bottom boundary for the Mississippi River Valley alluvial aquifer (the shallowest aquifer) in eastern Arkansas from well log-data collected by the U.S. Geological Survey. The software was then used to determine the depth of the aquifer bottom at reported well locations to ascertain whether the Mississippi River Valley alluvial aquifer or a deeper aquifer was the primary aquifer providing water to each well. The alluvial aquifer was identified as the primary aquifer for about 23,500 wells.     

GROUND WATER SIMULATION USING A ONE DIMENSIONAL FLOW MODEL1

ABSTRACT: In projects involving ground water problems, dependence on the mathematical modeling of the ground water flow phenomena is inescapable. At present, two dimensional flow models, which require tremendous amounts of computer time and storage, are generally used. When such bulky models are used for planning purposes, the two requirements (computer time and storage) can severely limit the number of alternatives that can be considered. A simple quantity and quality simulation model is developed here which requires considerably less computer time and storage and gives reasonably accurate results. The model was applied to simulate a ground water basin in San Luis Rey River in Southern California. The results were compared with those obtained by a USGS model. It was found that the simple model gave results which were consistentaly within five percent of the USGS model results, while the requirements on computer time and storage were drastically reduced.     

The demarcation of arbitrary boundaries for coastal zone management: The Israeli case

Integrated coastal zone management (ICZM) addresses the interconnections, complexities, and conflicts between many users of the coastal area with different goals. It requires setting managerial boundaries that capture many elements of human and natural systems. Experience teaches us that without a directed effort managerial rules and laws are not likely to coincide with the physical sensitivity of units that reflect different environmental characteristics of the coastal zone. Hence the aim of this study is to explore why coastal managerial boundaries are set arbitrarily and whether and how it is possible to address the problems this poses. We examine what influences the decisions of a new coastal management authority in Israel to determine how this body overcomes the limits of arbitrary boundary demarcation. The study found that real life management succeeded to both address areas outside the arbitrary boundaries and also to respect some of the different socio-economic needs and physical constraints of the coastal sub-units. Israel’s Coastal Environment Protection Law allows and, in fact, encourages the regulator to use discretion and to employ various criteria to balance development and conservation. This implies that policy makers are cognizant of a need to balance ecologically-sensitive boundaries that consider the homogeneity of the coast with politically feasible boundaries that are set arbitrarily.