A Sediment Budget for the Pipers Creek Watershed: Applications for Urban Stream Restoration

Abstract

Changes in land use and hydrology resulting from urbanization alter the processes of sediment production, delivery, and fluvial transport within a watershed. In this study, a sediment budget was constructed for the Pipers Creek watershed to determine how the magnitude and character of sediment production has changed as a result of basin urbanization and subsequent engineering efforts to control channel enlargement and erosion. In addition, the condition of instream sediment was evaluated to determine if the physical characteristics of the substrate currently constrains the quality of salmonid habitat. The sediment-production rate in the Pipers Creek watershed is half the estimated maximum sediment-production rate following the onset of urbanization but prior to effects to control erosion, but it remains six times higher than the estimated production rate before development. The quantity of coarse sediment being delivered into the channel is not a concern for resource managers; however, fine sediment being delivered by hillslope processes and urban runoff may impair quality salmonid habitat.