Abstract
It has long been recognized that nonpoint sources of pollution contribute significantly to receiving water loadings of both nutrients and toxic elements such as heavy metals (Harper, 1983; Sarton, et al., 1974). As a means of protecting Florida surface waters from the effects of nonpoint source pollution, the Florida Department of Environmental Regulation has establiched regulations which require new developments or projects to retain or detain specified volumes of runoff water on-site. In most cases runoff is collected in shallow ponds which infiltrate all or part of the retained or detained volumes into groundwaters.
When stormwater management facilities receive inputs of stormwater containing nutrients, heavy metals and other pollutants, processes such as precipitation, coagulation, settling and biological uptake deposit a large percentage of the input mass into the sediments. Recently, concern has been expressed that this continual accumulation of pollutants in the secdiments of stormwater management ponds may begin to present a toxicity or pollution potential to underlying groundwater. Specifically, do these pollutant accumulations cause physical and chemical changes to occur within the sediments of stormwater management facilities which mobilize certain pollutant species from the sediment phase into water phase.
The research efforts described in this report present a detailed investigation of groundwater impactes from four common stormwater management practices, including a wet swale, dry swale, wet detention pond and dual pond systems, receiving stormwater runoff from interstate highway, residential and commercial land use. Field investigations and laboratory studies began in October 1986 and continued through April 1988. in excess of 40,000 separate field and laboratory measurements were generated during the course of this project.
This report is divided into two separate volumes. Volume I is titled "Effects of
Stormwater Management Systems on Groundwater Quality" and contsis of a presentation and
discussion of the experimental data and conclusions. Volume II is titled "Effects of
Stormwater Management Systems on Groundwater Quality - Appendices" and contains the entire
data set of laboratory measurements and selected portions of the field data set.
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