Waller Creek Tunnel Project: Water Quality Action Plan

The City of Austin has long been interested in improving flood control and providing water quality enhancements to the lower Waller Creek Watershed. The City of Austin (COA) has conducted several flood management and water quality enhancement studies in this area which indicate that a stormwater bypass tunnel with surface-level inlet and outlet structures and a recirculation system would achieve the flood protection objective while also providing a means of improving the water quality within the lower portion of Waller Creek (COA, 1996; Loomis and Assoc., 1996). Design objectives for the Waller Creek Tunnel Project include effective flood control, water-quality enhancement, ease of operation and maintenance, cost-effectiveness and aesthetically pleasing above ground structures. The benefits provided by the project, both primary and secondary, include reducing floatable debris and sediment loading; as well as establishing a base flow to the lower portion of the creek which enhances its biotic and aesthetic nature. This paper summarizes previous data and reports produced for and by the COA on the water quality benefits the project will have on Waller Creek and Lady Bird Lake; no additional studies, calculations, or models were conducted as a part of this effort. The revisions to this paper dated October 13, 2008 were made in response to comments from the Environmental Resource Management Division dated September 22, 2008 (Revised September 26, 2008).Waller Creek Working Grou