From ceginfo@u.washington.edu Fri Mar 2 09:39:12 2001 Received: from jason01.u.washington.edu (root@jason01.u.washington.edu [140.142.8.10]) by lists.u.washington.edu (8.9.3+UW00.05/8.9.3+UW00.12) with ESMTP id JAA40948 for ; Fri, 2 Mar 2001 09:39:11 -0800 Received: from homer26.u.washington.edu (ceginfo@homer26.u.washington.edu [140.142.8.36]) by jason01.u.washington.edu (8.9.3+UW00.05/8.9.3+UW00.12) with ESMTP id JAA29636; Fri, 2 Mar 2001 09:39:06 -0800 Received: from localhost (ceginfo@localhost) by homer26.u.washington.edu (8.9.3+UW00.05/8.9.3+UW00.12) with ESMTP id JAA156590; Fri, 2 Mar 2001 09:39:04 -0800 Date: Fri, 2 Mar 2001 09:39:03 -0800 (PST) From: Civil and Environmental Engineering To: , Subject: MSCE Defense for Adrienne Miller 3/7 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII The final MSCE defense for Adrienne Miller will be held on Wednesday, March 7, 2001 at 2:00 p.m. in Wilcox 264. Title: Hydrologic Monitoring of the Seattle Ultra-Urban Stormwater Management Projects ABSTRACT Increased urbanization has lead to significant hydrological and ecological changes throughout the Puget Sound Lowland region. Direct physical alteration of the subsurface soil water storage capacity, natural drainage network, and land use patterns have permanently modified the hydrologic regime. The results are increased stormwater peak flow rates and volumes, increased frequency of floods, and decreased water quality in the receiving bodies of water. In an attempt to mitigate urbanization impacts, creative approaches are necessary to manage urban stormwater. This report documents the monitoring of two Seattle Public Utilities (SPU) "ultra-urban" stormwater management projects. In this context "ultra-urban" is defined as any built environment within the City of Seattle, including a variety of industrial, commercial, residential, and mixed land use types. The two ultra-urban stormwater projects monitored are the Viewlands Demonstration Swale and the Street Edge Alternative (SEA) Streets Millennium Project, located in the Pipers Creek Watershed in North Seattle. The projects are designed to benefit runoff-receiving waters both in reducing stormwater quantities and improving runoff quality. This report examines the hydrologic and hydraulic performance of the Viewlands Swale during post-construction monitoring and compares it to theoretical pre-construction performance. The results demonstrate that the Viewland Demonstration Swale is limited in its ability to mitigate large amounts of stormwater (above volumes produced by a 6-month, 24-hr storm), directly before it reaches the natural drainage network. The main constraint on swale effectiveness is its limited soil water storage capacity and available land area. Once storage capacity is reached over the course of a storm, the swale has little impact in attenuating peak flow rates or reducing inflow volumes. At the SEA Street site, baseline performance is monitored and compared to the theoretical performance of both conventional and post-construction street designs. The dominant characteristic of the residential block is runoff-response that is precipitation-driven and flashy. As a result, the runoff hydrograph closely follows the start, rise, and fall of the precipitation hyetograph. The post-construction performance of the SEA Streets project has yet to be made, but the project attempts to control stormwater production at the source and in the upper watershed. Hence it focuses on the root of the problem and recognizes that the impacts of the developed upper-watershed ultimately dictate the health of the stream. Professor Stephen J. Burges, Chair Professor Derek Booth .