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Introduction
Over the last century the Great Lakes have been subjected to many impacts from human activities: the release of nutrients and contaminants; resource harvesting, especially of fish; transformation of wetlands and other habitats; and entry, by accident or design, of nonindigenous species. But there has been progress in addressing these impacts: the lakes are in several ways cleaner today than they were in the 1960s, while awareness of the benefits of intact natural ecosystems and vigilance with respect to invasive species have increased.
One problem, however, remains unresolved, and indeed may have become worse in the last three decades: urban nonpoint source pollution (defined as urban runoff discharged into receiving waters in either of two forms: stormwater discharges from storm sewers, or overflows from combined sewer systems [Marsalek and Ng 1989]). This form of pollution has many origins. Contaminants generated in diverse ways-from atmospheric deposition to disintegrating tires-accumulate on impervious surfaces, and are then washed into streams and lakes. Septic systems release effluent. Millions of lawns are treated with pesticides and herbicides, much of which travels more widely.
Nonpoint source pollution from urban areas poses unique challenges. Most obviously, there are countless sources. Even more significantly, these sources cannot readily be eliminated, or cured through some "magic bullet". A variety of strategies have been developed to deal with nonpoint source pollution-some effective, others, less so. But this form of pollution is also rooted in fundamental aspects of the North American way of life: the expansion of low-density suburban areas; the fact that much of these areas consists of impervious, contaminated surfaces; and the transformation of natural habitats into suburban lawns, often drenched in herbicides and pesticides.
Just as the origins of nonpoint source urban pollution are diffused across the landscape, so too is responsibility for the problem. Regulation of urban development largely rests with hundreds of municipalities or other regional bodies within the Great Lakes region. These are often poorly equipped to adopt a broad, ecosystem perspective to the issue; they also often lack the expertise necessary to understand the problem or to regulate its sources effectively.
Given the complexity of the problem, and the lack of capacity of many of the responsible agencies, the challenge of using science effectively is an especially critical one. Attention needs to be focused not simply on research or information needs with respect to managing urban nonpoint source pollution, but on identifying problems in the linkage between scientific information and land use decisions more generally.
This document will focus on this challenge of ensuring effective links between science and land use policy: connecting what we know, with what we do. We will begin with an overview of urban development and its impacts in the Great Lakes region, and of responses to this issue. Available scientific information will then be surveyed, identifying significant uncertainties and information gaps. The prospects for applying this information to reducing the impacts of development will then be considered. Challenges in linking science with land use policy are then examined. First, general challenges evident across the Great Lakes region are identified. Second, a specific case study, that of urban land use decisions on the Oak Ridges Moraine, north of Toronto, is examined, in order to understand how scientific information is drawn on in suburban land use decisions. The choice of this case study was guided by the view that these challenges can only be fully understood within their specific local political and ecological contexts. The report concludes with recommendations for improving the science-policy link with respect to urban nonpoint source pollution.
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