Nearly a mile long and with an average diameter of 24 feet, the tunnel will capture and redirect flood waters.
When Bill Espey studied Waller Creek as part of his dissertation (“A Study of Some Effects of Urbanization on Storm Runoff From a Small Watershed”), he never imagined that almost half a century later he would be leading a $144 million Waller Creek Tunnel project to divert flood waters from downtown Austin.
He became familiar with Waller Creek, which winds through The University of Texas campus, in the mid 1950s when he came to UT on a football scholarship. He found his way to the Civil Engineering Department, where he completed his B.S., M.S., and Ph.D. “Maybe I can attribute my engineering career to my poor football skills,” he laughs.
“I was very fortunate to get a good sound foundation in engineering, hydraulics, and hydrology at UT,” says Espey, noting in particular the impact of his professors “the 3 M’s: Carl Morgan, Frank Masch, and Walter Moore, as well as former dean Earnest Gloyna.
”Much of his groundbreaking work in engineering and hydrology began at UT; the Urban Unit Hydrograph Equations he presented in his dissertation have been used in design and floodplain delineation throughout the country. And his work with Waller Creek, which has come full circle, comes with extraordinary benefits to the City and people of Austin.
“The results of the Waller Creek Tunnel project will be a drainage/floodplain/erosion solution that the City of Austin can use to create a master plan to guide development and improvements that will create an urban oasis,” says Espey.
Like many creeks in Central Texas, Waller Creek is prone to flash flooding, particularly along the lower portion, which flows through the eastern edge of downtown Austin to Lady Bird Lake.
"In search of an effective flood control solution, in 1999 the City of Austin selected Espey Consultants, Inc. (the environmental and engineering consulting firm founded by Espey in 1993) and Kellogg Brown & Root Services to design and manage the diversion of lower Waller Creek. The Austin City Council and Travis County Commissioners found a unique funding solution for the project, establishing a Tax Increment Financing District (TIF), in which a property tax increase was issued to those expected to benefit most from reduced flooding along the waterway.
Begun in 2011, the project includes a mile-long, underground tunnel extending from an inlet structure at Waterloo Park to an outlet near Lady Bird Lake. The tunnel portion of the project will be capable of diverting 85% of 100-year floodwater downstream to a lagoon at the edge of Lady Bird Lake. Also included in the project are two smaller, creek side inlets at 4th Street and 8th Street, which together will be able to redirect 15% of floodwater to the outlet lagoon.
Because the tunnel elevation will be lower than that of Lady Bird Lake, it will contain water at all times; to prevent this water from becoming stagnant, the inlet facility design features a pump station for the purpose of transferring water from the tunnel to Waller Creek. This means that perennial flows will be returned to Waller Creek, which currently runs dry during summer months. The inlet facility also includes an aeration chamber to ensure that water transferred to the creek will contain adequate levels of dissolved oxygen to support a healthy ecosystem, year-round.
Upon completion in 2014, the project will contain the 100-year floodplain within the channel of Waller Creek downstream of Waterloo Park and provide flood relief for nearly 28 acres of land currently subject to flooding and erosion, including approximately 42 commercial and residential structures and 12 roadway crossings. Once the tunnel is operational and the threat of flooding is reduced, the tunnel will allow public and private redevelopment of one million square feet of downtown Austin.
The people of Austin—sensitive to water and environmental issues and ever-protective of the natural terrain—expressed “overwhelming” concern, remarked Joe Pantalion (BSCE 1987), project sponsor, that the project respect the natural character of Waller Creek and Lady Bird Lake.
The main inlet, a rather significant structure, has been designed with a tremendous attention to detail. It will be energy efficient, architecturally pleasing, and environmentally thoughtful, incorporating a series of rock structures that allow migration of certain organisms up an “ecological ladder” from the creek through the upstream dam. The same careful thought has been given to the outlet structure on Lady Bird Lake.
“A tremendous effort was put into ensuring that this project met the engineering objectives of effective flood control but also remained harmonious with the environmental needs of the creek and surrounding areas,” explains Espey. “We gave great respect to the natural beauty and integrity of the creek.”
Throughout his career, Espey has accumulated extraordinary professional achievements and accolades, including being named Engineer of the Year by the Texas Society of Professional Engineers, the EWRI/ASCE Lifetime Achievement Award, and Department of the Army Outstanding CivilianService Medal. He is one of the founding member(s)of the Board of Trustees of AAWRE and on the Accreditation Board for Engineers and Technology (ABET). He was also appointed (USACE New Orleans District) as a member of the Independent Technical Review panel (ITR) for the USACE/FEMA Joint Texas Coastal Hurricane Surge Project.
In his 70’s, Espey is grateful for the opportunity to have worked on so many interesting projects around the country, and for being able to spend time with his family, including his wife of 51 years and his eight grandchildren. He appreciates that in many ways, the Waller Creek Tunnel project represents the best of the things he holds dear: engineering, innovation, and community engagement, all in the heart of Austin, his home.
For more information please visit: http://www.austintexas.gov/department/waller-creek
