ACWP

Year Completed:
In Progress

Construction Cost:
Estimated $101 Million

Client:

Contact: Name:
Gary Jackson, PMP

Nature of the Work:
  • Route Study
  • Design
  • Permitting
  • Bid Phase Services
  • Creek Remediation/Restoration
  • Construction Phase Services

Waller Creek Tunnel Project

Project Description

Waller Creek Tunnel Project

The Waller Creek 100-year floodplain covers much of downtown Austin, spreading out up to 800 feet wide in areas and leaving homes, businesses, and downtown parks at risk for severe flooding and stream bank erosion. As a result of the flood risk and consequent development limitations, the area has never reached its full potential as a vibrant, economically viable part of downtown Austin. Historically, Waller Creek has experienced several dangerous floods, including the flood of 1915, in which 35 people died; the events of September 1921, October 1973, Memorial Day Flood of May 24, 1981, December 1991, October 1998, November 2004 and January 2007. Since the 1970’s, diversion of Waller Creek flood flow has been a goal of the City of Austin to reduce the risk of flooding downtown, thereby encouraging planned development at the creek side and at the street level above.

In 1999, the City of Austin selected a joint venture comprised of Espey Consultants, Inc. and Kellogg Brown & Root Services, Inc. (JV) to provide professional services for preliminary design, final design and construction management services for the proposed Waller Creek Flood Diversion Tunnel Project in downtown Austin, Texas. The project design objective is to provide the City of Austin with a cost-effective flood control system for the lower Waller Creek (downstream of 15th Street) that will include multiple benefits such as: reduced flood risk, water-quality enhancement, aesthetically pleasing aboveground structures and ultimately, economic development. “The Waller Creek Tunnel Project is a long-term investment in Austin’s future and an opportunity to turn a forgotten, flood-prone creek into a vibrant part of downtown,” said Council Member Sheryl Cole.

The project consists of a one-mile long, 20- to 26-foot diameter “inverted siphon” bypass tunnel, inlet and outlet facilities, and two creek side inlets. During flood events, the main inlet at Waterloo Park will divert stormwater from approximately 85% of the 5.75 square mile watershed through the tunnel directly into Lady Bird Lake at Waller Beach. The two visually obscured creek side inlets located upstream of 4th and 8th Streets will divert additional stormwater flow from the lower portion (approximately 15%) of the watershed through a series of shafts and tunnels into the main flood control tunnel. During normal, dry weather conditions, water will be pumped from the tunnel at the inlet in Waterloo Park and discharge into Waller Creek to maintain a constant flow in the creek, improving water quality and the appearance of the creek. In order to prevent regular required maintenance of the tunnel and improve water quality, stormwater screening and debris removal will be performed at surface level at the main inlet and at the two creek inlets at 4th and 8th Streets.

Upon completion in 2014, the project will contain the 100-year floodplain within the channel of Waller Creek downstream of the 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. The project will result in construction of a new Parks and Recreation Department (PARD) boat facility, improvements to Waterloo Park, and surface improvements adjacent to the creek side inlets. Once the tunnel is operational and the threat of flooding is reduced, the tunnel will allow public and private redevelopment so that the community’s vision for the remainder of the area may be achieved.

Construction

Waller Creek Tunnel Project

The $144M Waller Creek Tunnel project is divided into four main sub projects (Main Tunnel / 4th Street Creek Side Inlet, Outlet Facility at Waller Beach, Inlet Facility at Waterloo Park, and 8th Street Creek Side Inlet) in order to streamline the construction schedule, solicit contractors with appropriate skill sets and attempt to increase the number of bidders. The project also includes several auxiliary sub projects including the relocation and replacement of the PARD Boat Facility at Waller Beach, the replacement of the Lady Bird Lake Hike & Bike Trail Pedestrian Bridge over Waller Creek, and site restoration after the main construction projects are complete. A description of the four main sub projects follows:

Construction of the Main Tunnel / 4th Street Creek Side Inlet sub project is scheduled to start in spring of 2011. This sub project includes construction of the main tunnel, including excavation, initial supports and final concrete lining, and the 4th Street creek side inlet facility and associated creek improvements. An access shaft will be excavated and materials will be removed from a construction staging site at the northwest corner of East 4th Street and IH-35 located near the midpoint of the tunnel alignment. The tunnel will be constructed 60 to 70 feet underground using a roadheader method of construction with both northern and southern headings. The excavation will not require trenching, and individuals on the surface will likely not realize construction is taking place far below them. The 4th Street Creek Side Inlet will consist of a small in-channel dam / ecological grade control structure, side overflow weir, and underground screening facility that will divert additional stormwater in the downtown area into the main flood control tunnel.

The Inlet Facility at Waterloo Park sub project is scheduled to start construction in the fall of 2011. Located in Waterloo Park, this contract will include a large morning glory spillway inlet to divert creek flows into the tunnel, an enclosed pump station, trash and debris management system, and a pond to reduce the velocity of flood waters approaching the inlet facility.

The Outlet Facility at Waller Beach sub project is scheduled to start construction in the spring of 2012. This contract will include a tunnel outfall structure and lagoon adjacent to Lady Bird Lake. The outfall structure will primarily be constructed below grade and will discharge flood waters into the lagoon and then into Lady Bird Lake.

The 8th Street Creek Side Inlet sub project, located between 8th and 9th Streets is scheduled to start construction in spring of 2013. Similar to the 4th Street Creek Side Inlet, this facility will consist of a small in-channel dam / ecological grade control structure, side overflow weir, and underground screening facility that will divert additional stormwater in the downtown area into the main flood control tunnel.

Funding

In 2007, the Austin City Council and Travis County Commissioners joined forces to fund the tunnel by creating a Tax Increment Financing District (TIF) including properties alongside Waller Creek between Waterloo Park and Lady Bird Lake. The City of Austin will contribute 100% of its property tax revenue from the TIF and the County will contribute 50% of its tax revenue. The TIF will terminate after 20 years in 2028. Revenues will go toward debt service of the bonds to be issued for the tunnel’s construction as well as costs for operations and maintenance during the first 20 years. After the TIF terminates, the City will take over the cost of maintaining the tunnel.

 

 

 

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