In most of the developed countries of the,World, significant efforts to control the pollution of surface waters have been underway for decades, and particularly the last 10-15 years. These efforts have focused mainly on eliminating or mitiga ting the effects of point sources of pollution. In many ca ses, however, it is clear that we have achieved only limited improvement in water quality, and that non-point sources of pollution are going to control any further improvement. It has long been known that urban runoff is a major non-point source, and much research has been done in an attempt to un derstand the mechanisms and processes which govern this source and to reduce or eliminate its impacts. Many urban jurisdic tions have adopted urban runoff pollution control measures, in spite of the fact that there is a great deal that we still do not know, and without really being able to quantify the benefits achieved. A major problem is that while a great deal of work is being done, both in Europe and North America, it is very difficult to keep abreast of new developments. The Urban Water Resources Research Council of the American Society of Civil Engineers has for many years had as one of its major objectives the transfer of urban runoff technology among researchers and practitioners in the field, as well as to those engineers who are not in the forefront but who nonetheless need the information on the latest developments.

The rapid conversion of land to urban and suburban areas has profoundly altered how water flows during and following storm events, putting higher volumes of water and more pollutants into the nation's rivers, lakes, and estuaries. These changes have degraded water quality and habitat in virtually every urban stream system. The Clean Water Act regulatory framework for addressing sewage and industrial wastes is not well suited to the more difficult problem of stormwater discharges. This book calls for an entirely new permitting structure that would put authority and accountability for stormwater discharges at the municipal level. A number of additional actions, such as conserving natural areas, reducing hard surface cover (e.g., roads and parking lots), and retrofitting urban areas with features that hold and treat stormwater, are recommended.

This manual comprises a holistic view of urban runoff quality management. For the beginner, who has little previous exposure to urban runoff quality management, the manual covers the entire subject area from sources and effects of pollutants in urban runoff through the development of management plans and the design of controls. For the municipal stormwater management agency, guidance is given for developing a water quality management plan that takes into account receiving water use objectives, local climatology, regulation, financing and cost, and procedures for comparing various types of controls for suitability and cost effectiveness in a particular area. This guidance will also assist owners of large-scale urban development projects in cost-effectively and aesthetically integrating water quality control to the drainage plan. The manual is also directed to designers who desire a self-contained unit that discusses the design of specific quality controls for urban runoff.

90 charts and tables.