Assessing the incorporation of watershed protection techniques in new urban versus conventional low-density development site plans.

摘要

Polluted runoff is the largest source of water resource degradation in the United States. Sprawling urban development, accelerating during the second half of the twentieth century, is the primary reason. Although researchers have not derived clear solutions to the problem, most agree that the spatial unit on which to focus strategy is the watershed: the entire physical area or basin drained by a stream or river.; This study examines the role of the local development planning process in formulating a strategy to integrate more watershed protection techniques in the site plans prerequisite to urban development. Several factors are posited to have a significant effect on the number of techniques that reduce impervious surfaces, protect hydrologically sensitive areas, and achieve stormwater runoff management (known collectively as site plan watershed protectiveness). Possible predictors of site plan watershed protectiveness are site plan design (new urban versus conventional low-density), community development management program, planning staff commitment and capacity to achieve watershed protection, and site and community context. Surveys of 100 site plans and case studies of six new urban site plans were administered to assess predictors of site plan watershed protectiveness.; The key findings from the study support that new urban site plans exhibit greater watershed protectiveness than conventional low-density site plans. Also, the more watershed protective policies incorporated in a community's development management program, the greater the site plan watershed protectiveness. The best examples of watershed protectiveness are those sites where watershed protection policies, anchored by a land suitability analysis, frame a strong new urban site design. Such examples successfully compact development in less hydrologically sensitive areas by reducing imperviousness and preserving open spaces for stormwater runoff management.; Additional findings from the study show larger sites provide more opportunities to incorporate watershed protection techniques. Older sites exhibit lower site plan watershed protectiveness because of more recent awareness of polluted runoff as the leading cause of watershed degradation. Finally, local planning staff commitment and capacity to achieve watershed protection do not significantly affect site plan watershed protectiveness, although it is important to recognize they are likely key players in the development of the watershed protection policies that do have a significant effect.