University of New Hampshire Stormwater Center 2005 Data Report
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About this Report

In 1998, Phase II of the Clean Water Act broke over U.S. towns and cities a bit like a storm. The purpose of the new regulations was to reduce the impact of nonpoint source pollution carried by stormwater runoff—the single greatest threat to water quality nationwide. Under Phase II, governments of communities under 100,000, as well as commercial enterprises, are required to develop stormwater programs to improve water quality and reduce the volume of runoff.

To create the infrastructure for these programs, there is no lack of stormwater treatments from which to choose—from long, winding swales that sweep along roads and highways to manufactured systems that fit neatly in a manhole. The challenge that land use decision makers face is choosing an approach that will do the best job of protecting local water quality, is within their budgets, has a proven operations and maintenance record, and will meet regulatory requirements. The information needed to make these decisions is not readily available, particularly for emerging stormwater treatments. Unfamiliar with new technologies, and lacking access to performance data, engineers, planners, and regulators are often slow to adopt them.

At the same time, the reliability of traditional approaches is in question. A three-year study of nine New Hampshire sites in the 1990’s found that using conventional stormwater treatment practices degraded water quality with regard to at least one contaminant at least two-thirds of the time. When it comes to manufactured stormwater treatments, end users must rely on vendor claims about product performance—much of which is based on data collected in the laboratory, not the field.

The University of New Hampshire Stormwater Center was created to address this critical lack of information. This inaugural report is a compilation of data from our first year of monitoring the effectiveness of stormwater treatment systems in addressing water quality and the volume of runoff. We hope that it will become a valued resource for those who must comply with Phase II rules. It is, however, only the beginning. We will continue to refine our methods and broaden the scope of our evaluation to meet both the needs of stormwater managers and the rigorous scrutiny of the research community.