EXH1071039925

Richard R. Homer *'2,M. ASCE; Derek B. Booth2; Amanda Azous_; and Christopher W. May2 By the mid-1980s it was clear that urban stormwater runoff was strongly implicated in the alteration of streams and freshwater wetlands in the Puget Sound Basin of Washington state to ecosystems lower in biologically diversity and productivity of the species most valued by society. I.twas also apparent that the causes of these modifications were rooted in watershed hydrology and sediment transport as well as reduced water quality. Recognition of these connections and the rapid pace of , development in the region stimulated research to define the linkages among stream and wetland habitatstructure, conditions in the surrounding laAdscapes, and the _sociated biological responses. One project monitored watershed and riparian zone conditions, flow, physical habitat characteristics, water quality, benthic macroinvertebrates, and fish in 31 reaches on 19 low-order, Streams, representing a gradient of urbanization, over a three-year period. A second project followed 19 palustdne wetlands during an eight-year period when urbanization began or increased in the watersheds of about half, while the remainder were essentially unchanged. Overall, the findings of these projects agree that the effects of modified hydrology accompanying-urbanization exert the earliest and, at least initially, the ._tzongestdeleterious influences on the freshwater ecosystems studied. Further- more, the results agree that the steepest rates of decline in biological functioning of both streams and wetlands, and the conditions necessary to support that function- ing, occur as urbanization increases total impervious land cover from 0 tO about 6 percent, unless…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]