BOOK REVIEWS

Ernst M. B v i s , Ph. D. Associate Professor of Environmental

The University of Texas at Houston School of Public Health Houston, Texas

Science

Development of a General Planning Methodology for Storm Water Management in Urban Watersheds, Lindell E. Orms- bee, J. W. Delleur, and Mark H. Houck. Water Resources Research Center, Purdue University, West Lafayette, Indiana. Technical Report 163, Submitted to Bureau of Reclamation, Grant 1434-001-0498. March 1984. 217 pages. No charge.

This report addresses the problem of planning detention basins for the control of stormwater runoff in urban areas. The use of detention basins is and will continue to be one of the prime techniques for controlling flows and pollutant loads. However, a detention basin may cause higher flows down- stream than would occur naturally, if, for example, the peak runoff from the basin were lagged to coincide with the peak runoff from another sub-catchment. Thus flood control sys- tems should be designed on an area-wide or regional basis rather than on a sub-area, piecemeal basis. (This argument in no way supports the adoption of the recommended metho- dology, of course; it merely supports region-wide planning.)

The report purportedly develops new methodology for use in the planning of systems of detention basins in urban water- sheds for both pollution management and flood control. The methodology employs continuous simulation, statistical analy- sis, and a general design “heuristic” in an effort t o obtain an optimal (least-cost, maximum benefit), integrated system of detention basins. Water quantity and water quality constraints are considered. Several different approaches were considered in the development of the design heuristic. The recommended methodology uses a dynamic program to obtain a feasible starting point for a nonlinear search algorithm. The nonlinear search algorithm employs the Complex Method of Box. The methodology was applied t o a watershed in Glen Ellyn, I1- linois, and to an imaginary watershed derived from average geomorphic data for the state of Indiana.

The 21 7-page report is reproduced from a reasonably read- able dot-matrix printer using double spacing, and the stand- ard of the illustrations and other mathematical symbols is quite good. The format is the normal 8%’’ x 11”. A good literature review is presented (30 pages, 139 references), and the development of the detention basin design procedure is presented in some detail. The application of the methodology to the two watersheds is similarly presented in detail. Un- fortunately, neither listings nor schematics of the code are presented, and the hydrological treatment is sketchy. The report includes 30 tables and 35 figures.

A discussion of water quality and methods of estimating the pollution control capability of detention basins and ponds is presented. Suspended solids are taken to be one of the

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major contributing factors to pollutant buildup. While good historical data are lacking, it has generally been found that detention basins can reduce suspended solids by up to 9 0 per- cent, heavy metals by up to 80 percent, and BOD and TOC levels by 10-25 percent. The report reviews three different methods of handling hydrologic input data: design storm analysis, continuous simulation, and the derived distribution approach. The merits and drawbacks of each of these methods is discussed. Four models for overall planning methodology were considered: SWMM3, STORM, DR3M-QUAL, and HSPF. The SWMM3 model was chosen because of its capabilities and relative ease of use. (Readers may wish to consider other criteria such as algorithms for pesticides, computing environ- ment, resolution, etc.)

After considering various linear and non-linear program- ming methods, the authors chose a non-linear, dynamic pro- gramming approach. The use of a direct formulation utilizing the Box Complex method is the basis for producing the general detention basin design procedure. This results in a design for a specific design event.

The 534-acre Glen Ellyn watershed located in Illinois was used to test the method. Four different cases based on vary- ing cost and constraint selections were studied by applying the general design “heuristic” and a composite design event. The results indicated a tradeoff between storage capability and pipe costs, which in turn depends on the specific case being investi- gated. The application is close to a sensitivity analysis.

The report finally deals with a generalized watershed appli- cation, wherein representative planning indices are established using average design parameters and average values of water- shed parameters, both geomorphic and hydrologic, such as Horton’s laws, Shreve network classifications, the Random Topology Model, and the WATER computer program. Hydro- logic considerations such as land use data, pollutant loading data, and precipitation data are also covered. Hydrographs for both developed and undeveloped conditions were com- puted, and the detention basin planning methodology applied for a design period of 20 years. A statistical analysis was per- formed on continuous results for both conditions. A com- posite design event was derived for each selected design fre- quency.

The design heuristic was applied to the imaginary repre- sentative watershed and an attempt was made to derive a simple design that would meet all constraints for all fre- quencies. Two strategies were studied: a sequential design process and single design approach. The authors conclude that (a) the single design strategy produced designs that satis- fied both the pollutant and flow rate constraints at the lower design frequencies, (b) neither strategy is consistently superior, (c) the single design strategy will always produce the least cost design, and (d) the sequential strategy will usually produce a feasible design. The authors caution that further case studies are required. No evidence of the optimality of the algorithm is given.

So much for the content of the report. The main objective was stated to be a general planning methadology that can be used to design and locate a system of detention basins in urban

WATER RESOURCES BULLETIN

BOOK REVIEWS

areas so as to minimize costs and maximize water quality (minimize water quality degradation). The answer to the ques- tion of whether the report meets its objectives depends upon your point of view. Conservative readers will accept the basic premise that a large number of long computer runs is costly. They would also warily adapt event modeling to fit into the giddy world of coarse, continuous modeling. My view is more liberal: continuous SWMM3 can now be run, perhaps in vari- able time-steps, on IBM-PC compatibles at little or no cost at all. Why not do so? The authors used 60-minute integration intervals. In urban hydrology, where severe storm hyeto- graphs may last only 20 minutes and flood hydrographs 40 minutes or less, this makes little sense. They also considered spatial effects of detention storage without modeling spatially limited storms, or storm kinematics. This surely places the cart before the horse. Finally the report evidently offers little new guidance on joint design of a multitude of storages for both pollution abatement and flood control, especially where dry-day accumulation rates for various pollutants differ across the whole catchment.

“Heuristic” in this case means a search procedure. In computer-aided-design the word could literally denote a pro- cedure that helps in the solution of a problem, because it renders useful empirical results, but is otherwise incapable of justification, due to vague or dubious assertions. The al- gorithms described, however, are evidently fundamentally sound. Moreover they are not “heuristic programs” because they do not automatically produce initially exploratory de- signs and, thereafter, utilize artificial intelligence techniques to automatically improve the design against an established database.

It is difficult to understand why so much effort continues to be spent on event modeling. A system of detention basins is probably important enough to be designed over two days using a $2500 personal microcomputer and continuous SWMM3, especially since storm kinematics and pollution loadings can be more or less correctly computed. Surely continuous modeling is no longer just another typical academic pipedream.

William James Computational Hydraulics Group McMaster University Hamilton, Ontario, Canada

Water Management: Technology and Institutes, Warren Viess- man, Jr. and Claire Welty. Harper & Row. $41.95.

Professors Viessman and Welty have produced a text book that I have looked forward to for years. The politics and in- stitutions guiding water resources policy are far too often ig- nored while technical specialities of hydrology, structural de- sign, economics, or ecology are pursued. The detachment is frequently so great that beginning practitioners in water re- sources planning, design, and management are somehow con- ditioned to believe that a good project is one that maximizes

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net benefits for some combination of water resources program objectives - reduced flooding, increased water supply, treat wastewater treatment, navigation, or other services. When the single dimensioned decision model is ignored by the decision- makers, a high level of frustration often developes. This book makes substantial strides in providing a perspective of the necessary complexity of the objectives and the dimensions of water resources decisionmaking. The authors provide a good introduction to the historical evolution of Federal Water Re- sources Policy.

However, somehow the authors slight some of the richest political rationale for water resources development. Perhaps, because of their prescriptive conclusions about current na- tional priorities and current public perception, the potential utlity of navigation, water supply, wastewater treatment, flood control, and other water resources projects, to influence eco- nomic development and settlement patterns in localities and regionals of the U S . are not discussed. Thus, a major factor which continues to drive political assessment of project alter- natives and decisionmaking objectives is not included. One can argue this position from either a pro development or anti- development stance. However, most of the water resource interests continue to believe and act on the proposition that water projects do influence growth and that growth is not the same with and without projects, even when it comes from en- vironmentally oriented interests who are opposed to growth.

In spite of these reservations, this book provides balance in engineering, economic, environmental, institutional, and poli- tical factors that influence the definitions of objectives and the design and evaluation of alternatives which meet the ob- jectives of water development. Professor North’s chapter on economic analysis, the extensive discussion of various water resource simulation and optimizing models, and Professor Louch’s summary of case studies are balanced and thorough without being overloaded with systems (or other technical) jargon. The writers and editors have accomplished an extra- ordinary feat.

This book should find frequent use in undergraduate courses in water resources management (as intended), as well as courses on policy analysis, resource economics, and environ- mental economics and should be present in the library col- lections of professional water resources practitioners.

Lloyd G. Antle, Ph.D. Chief, Navigation Division U.S. Army Corps of Engineers Institute for Water Resources Fort Belvoir, Virginia

Water for the Energy Market, John A. Folk-Williams and James S. Cannon. Western Network, 214 McKenzie, Santa Fe, New Mexico. 1983. 162 pages. $35.00.

This book examines conflicts between one type of energy development - coal - and water resources in six states: New Mexico, Colorado, Utah, Wyoming, Montana, and North

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