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SEDIMENT SOURCES IN AN URBANIZING, MIXED LAND-USE WATERSHED. (R825284)
Citation:
Nelson, E. J. AND D. B. Booth. SEDIMENT SOURCES IN AN URBANIZING, MIXED LAND-USE WATERSHED. (R825284). JOURNAL OF HYDROLOGY. American Chemical Society, Washington, DC, 264(1-4):51-68, (2002).
Description:
Abstract
The Issaquah Creek watershed is a rapidly urbanizing watershed of 144 km2 in western Washington, where sediment aggradation of the main channel and delivery of fine sediment into a large downstream lake have raised increasingly frequent concerns over flooding, loss of fish habitat, and degraded water quality. A watershed-scale sediment budget was evaluated to determine the relative effects of land-use practices, including urbanization, on sediment supply and delivery, and to guide management responses towards the most effective source-reduction strategies. Human activity in the watershed, particularly urban development, has caused an increase of nearly 50% in the annual sediment yield, now estimated to be 44 tonnes km-2 yr-1. The main sources of sediment in the watershed are landslides (50%), channel-bank erosion (20%), and road-surface erosion (15%). This assessment characterizes the role of human activity in mixed-use watersheds such as this, and it demonstrates some of the key processes, particularly enhanced stream-channel erosion, by which urban development alters sediment loads.
Author Keywords: Sediment budget; Urbanization; Washington; Development; Streams