HDR Inc. has been given the Eastern Municipal Water District contract for the preliminary and final design of the erosion mitigation project for the Warm Springs Creek sewer crossing.
Eastern’s board voted 5-0 Oct. 7, to award HDR, which is based in San Diego, the $152,900 design contract. The board action also appropriated $392,900 to fund the contract, the geotechnical and other survey work to be conducted during the design phases and the initial environmental planning and permitting.
The district installed a sewer across Warm Springs Creek in 2004. The sewer provides service to approximately 850 homes in Murrieta and to Daniel N. Buchanan Elementary School. The alignment runs from Manzanita Street through undeveloped land and crosses under Warm Springs Creek before discharging into the Warm Springs Creek Interceptor Sewer.
Recent storms have caused damage to the articulating concrete block installed on top of the sewer and the concrete encasement surrounding the sewer, which were included in the construction as erosion protection measures. An August 2020 EMWD administrative action provided HDR with a contract for $88,820 to perform a hydrologic assessment of the creek. HDR determined that flow velocities within the creek can exceed the velocities recommended for the application of articulating concrete block as an erosion control measure. The damage to the articulating concrete block and the effects of head cutting downstream into the concrete encasement has caused an erosion mitigation measure to be deemed an urgent issue to be addressed on an expedited basis.
After HDR completes the design phase, the construction work will replace the existing erosion control measures with engineered riprap within the high water mark of the streambed. The environmental planning and permitting will require coordination with the U.S. Army Corps of Engineers, the Regional Water Quality Control Board, the California Department of Fish and Wildlife and the Riverside County Flood Control and Water Conservation District.
Eastern has a list of on-call engineering consultants, and the competitive selection process determined that HDR’s performance of similar services for the district made the company the preferred consultant. EMWD staff negotiated the $152,900 contract amount with HDR.
Joe Naiman can be reached by email at firstname.lastname@example.org.