SAWS Multiple Sewershed Package 6

Project Purpose

KFA assisted with the rehabilitation of approximately 8,694 LF of 21”-48” diameter deteriorated wastewater main using CIPP as part of the SSO Program. In addition to trenchless rehabilitation, approximately 1,137 LF of 24” diameter wastewater main is to be fully replaced via open cut construction. The segments are located at 18 different project locations throughout the city of San Antonio.

Project Approach

KFA was awarded a work order off the 2017 Pipelines Engineering Condition Improvements Contract to perform the pipeline design for the rehabilitation and replacement of approximately 9,831 LF of 21”-48” wastewater main. KFA staff managed four subconsultants (archaeological/environmental, survey, civil, cost estimating), developed the project schedule, and led meetings with SAWS. KFA performed a field investigation of all of the project locations and reviewed CCTV to establish locations for point repairs and obstruction removals. KFA coordinated with the city of San Antonio and TxDOT for ROW permits, the San Antonio River Authority for access agreements, and the city of San Antonio TCI department for floodplain development permits. Traffic control was a challenge for multiple sites, with many of them located in heavily traveled roadways. KFA developed preliminary bypass pumping layouts and estimated the number of pumps required in order to accurately account for the large layout required at the suction manholes. One of the more challenging segments was located along SW 36th Street, as the segment extends into the intersection of Castroville Road which is a heavily traveled 5 lane roadway. This section required open cut construction because the existing main was in too poor a condition to allow for CIPP. While construction is being completed in the intersection, coordination with Silber Eagle Distributors is required as multiple lanes will need to be shut down and detoured around. The wastewater main cannot be accessed by heavy equipment through the golf course without causing significant damage to the fairways, requiring the site to be access from the dam. KFA was concerned about the weight of the CIPP liner and the ability of the equipment to traverse the flood retention dam. KFA proposed adding an additional pipe segment downstream of the pipe that was originally identified to be rehabilitated, allowing for a more easily accessed location for insertion of the CIPP liner and eliminating the need to transport the liner into the golf course. Another pipeline segment is located within the SAWS Medio Creek Wastewater Recycling Facility. KFA developed special provisions to address concerns about temperatures and styrene levels within the cure water to avoid upsetting the treatment process.

Project Results

This project addressed numerous segments of high priority large diameter projects as part of the SSO Program for SAWS. Traffic control was of primary importance for many of these segments located in congested roadways, careful planning helped minimize negative impacts during construction.