TRA West Fork (WF) 10 and 13 Wastewater Interceptor
Bedford and Euless, Texas
NDM completed the preliminary analysis, design, and plan preparation for the replacement of 6,000 LF of existing gravity sewer line and two meter stations at the West Fork Interceptor. The proposed pipeline improvements included 160 LF feet of 12-inch and 27-inch line; 1,000 LF of 21-inch line; 4,700 LF of 15-inch line; and 685 LF of 8-inch line. The two meter stations included Parshall flume assemblies of 6-inch and 9-inch widths. The project included the rehabilitation of an existing 12-inch line, connection of existing lines, closed-circuit television (CCTV) of the existing line, and access ramps. The evaluation of rehabilitation options included pipe bursting with line replacement, slip lining, and cured-in-place. The cured-in-place approach was selected as the preferred rehabilitation option because it improved the system hydraulic performance, allowed for elimination of aerial crossings, and was less costly than pipe bursting. Project tasks included phasing of improvements, incorporation of Phase 2 improvements into the design/build improvements at SH 183, constructability review, environmental analysis/permitting, survey, and easement preparation. The constructability review and project evaluation resulted in adjustments to the proposed alignment to address costs and potential construction risks. This evaluation included the development of OPC’s that compared rehabilitation with cured-in-place to options without rehabilitation; tunneling portions of improvements to eliminate construction, access, and easement issues related to open cut; and pipeline adjustments to reduce construction risks, eliminate impacts to adjacent apartment complexes, and minimize tunneling costs.