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- Info
Urban stormwater hydrology
| Author: |
Kibler, David F. ed. |
| Date: |
1982 |
| Periodical: |
Water Resources Monograph 7. Washington, DC: American Geophysical Union. |
| Abstract: |
The primary purpose of this monograph is to present in a coherent fashion the state of the art in urban hydrology and stormwater management. A secondary objective is to communicate recent research findings as they apply to improved methods of analysis of urban runoff. This monograph attempts to bridge the gap between current practice and research. The first chapter is an introduction to urban hydrology and stormwater management. The effects of urbanization on the quantity and quality of the runoff and the associated problems are presented in general terms. A brief history of urban hydrology highlights the progress made during the last decade. The interaction of the land use and urban runoff is presented in quantitative terms followed by a brief discussion of urban air quality since it affects stormwater quality. The chapter closes with a section on stormwater planning in the urban metroplex which includes a brief discussion on urban water balance, an introduction to stormwater and land use models and their use as elements of urban planning. Chapter 2 discusses the concept of the 'design storm' which provides a means of estimating rainfall depth or intensity for a specified duration and frequency, which in turn can be used in estimating runoff peaks and volumes. In the early applications the rainfall intensity-duration-frequency relationships were used to obtain a rainfall intensity of uniform duration for use with the rational formula. More recent applications include the development of a synthetic hydrograph or storm profile. Recent research has demonstrated the limitations of the design storm concept. Chapter 3 deals with rainfall losses in the form of interception, depression storage, and infiltration. The methods of estimating these losses are basic to both the desktop and the computer-oriented methods of analysis. It is one of the topics which has received little attention by researchers during the last decade. Nevertheless, it is a very important part of the rainfall-runoff process in urban areas. Frequently, the most important parameter in determining the abstractions from urban areas is the exact determination of the impervious areas directly connected to the drainage systems since these areas contribute, almost instantaneously, a runoff volume very close to the amount of incident precipitation, while most of the rainfall on the pervious areas and on the areas not directly connected may infiltrate and does not produce immediate runoff. Chapter 4 is concerned with simplified methods for urban stormwater calculations. Traditionally, the rational formula has been used for estimating the peak runoff from small urban catchments. During the last 15 years an increased awareness of the limitations of the rational formula has evolved. An important limitation of the rational formula is that it is concerned only with a peak flow and is thus of little help to quantify those effects which depend upon the availability of a sewer outlet hydrograph. A modification of the rational method for estimating detention storage volumes is presented in chapter 4 along with several other methods capable of producing an outlet hydrograph. Simplified methods are also given to estimate the annual pollutant loads from urban watersheds. The pollutants considered are the biological oxygen demand (BOD), total organic carbon (TOC), suspended solids, volatile solids, phosphates, total nitrogen, and coliforms. The detailed formulation of stormwater runoff processes and their inclusion in large-scale simulation models are discussed in chapter 5. The surface runoff and transport subsystems are discussed first, leading to the receiving water subsystem. The combined sewer systems encountered in many older cities are described, followed by the conceptualization of the physical drainage as used in simulation models. The basic hydraulic transport equations for the channel and sewer transport system are stated. Chapter 6 describes the quality aspects of urban runoff starting with the, water quality criteria for urban stormwater and combined sewer overflows. The entry of pollutants from dry fall and wet fall is quantified, leading to the determination of the pollutants washed off. Chapter 7 discusses data collection and instrumentation. It covers in some detail the techniques and procedures used by the U.S. Geological Survey (USGS) for the measurement of precipitation (dry fall and wet fall) quantity and chemical constituents and runoff quantity and chemical and bacteriological constituents. The primary flow measuring devices are compared, and the water quality constituents analyzed in the current EPA/USGS urban runoff program are listed, along with a discussion of automatic sampling techniques. The typical installation of the USGS urban hydrology monitoring system is described in detail. Chapter 8 gives an overview of the principal large-scale planning and design urban runoff models. These include such programs as STORM, SEMSTORM, ILLUDAS, SWMM, RUNQUAL, HSPF, and others. The basic objectives and generalized flowcharts are given for these several models. The application of the models, with examples, are discussed in chapter 9. The several flow management alternatives are discussed. An example is given of the application of ILLUDAS and QUAL-ILLUDAS to Bloomington-Normal, Illinois. Finally, the chapter closes with examples of the application of the transport block of SWMM to analyze complex sewer systems subject to extensive surcharging. |
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