HYDRAULIC AND ECONOMIC BENEFITS OF DOWNSPOUT DWERSION1

Authors

  • Martin M. Kaufman,

    1. Assistant Professor, University of Michigan-Flint, 516 Murchie Science Bldg., Flint, Michigan 48502–2186; and Waterworks System Operator, Beecher Water District, 1057 West Louis, Int. Morris Twp., Michigan 48458.
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  • Matthew Wurtz

    1. Assistant Professor, University of Michigan-Flint, 516 Murchie Science Bldg., Flint, Michigan 48502–2186; and Waterworks System Operator, Beecher Water District, 1057 West Louis, Int. Morris Twp., Michigan 48458.
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  • 1

    Paper No. 96155 of the Journal of the American Water Resources Association (formerly Water Resources Bulletin). Discussions are open until October 1, 1997.

Abstract

ABSTRACT: A downspout diversion program in an urban area is evaluated to assess the impacts on sanitary sewer flow volumes and cost effectiveness. Sanitary sewer flows and wastewater treatment cost data are compared for the five years before and 1.25 years after the downspout diversion was completed. In order to establish a cause and effect relationship between flow volumes and downspout diversion, measurements of precipitation, consumption patterns, and system loss (maintenance, fire flows, main ruptures) for the before and after time periods were obtained. The results indicate the downspout diversion contributed to a reduction of over 25 percent in the mean flow volumes within the sanitary sewer collection network during all rainfall events, with flow reductions ranging from 25 percent to 62 percent for rainfall depths between 6 mm (0.25 inches) and 25.4 mm (1.0 inches). Costs incurred for wastewater treatment were also reduced significantly, as overtime for overflow maintenance was eliminated. Downspout diversion is a viable nonstructural alternative for sthrmwater flow reduction in highly urbanized communities which may lack available space for large scale detention facilities.

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