The Adams Street Water Main Replacement Project will replace approximately 14,020 linear feet (LF) of 18- to 24-inch DIP transmission water mains along Adams Street in North Indio adjacent to the Sun City Palm Desert subdivision with 24-inch zinc-coated DIP wrapped in polyethylene. The existing northern end of the pipeline is located within the subdivision in Falsetto Drive, which is congested with utilities and cannot accommodate a pipeline replacement. Therefore, the northern end of the pipeline (approximately 1,970 linear feet of the total 14,020 linear feet) would be installed in the future Adams Street alignment. This alignment jogs to the east, resulting in a slightly longer new alignment; therefore, this section is referred to as a realignment/extension. The project would also replace approximately nine fire hydrants and approximately 30 1-inch domestic water service lines. Pipeline would be replaced along Adams Street right-of-way between Espana Boulevard (to the south) and undeveloped Coyote Song Way (to the north) (shown as Frances Way in some maps).
The purpose of the replacement project is to maintain reliability of service, minimize disruptions to customers and the community, and avoid costly emergency repairs. The area has corrosive soils which have damaged the existing DIP water main causing leaks, including a major leak in December 2017. These leaks result in a lack of water service to customers during repairs, disruption to the community, unexpected expenses, and additional staff time to address the impacts resulting from the pipe failures
Project design specifies that the majority of the replacement water main would be installed utilizing an open-cut construction methodology and approximately 285 LF of trenchless installation. A total of two sections of pipeline would be installed using trenchless drilling techniques to avoid underground utilities and a drainage feature located at the existing flood control channel of the Sun City Palm Desert subdivision. Approximately six air release valves and five blow-off assemblies would also be installed along the water main at localized high and low points. The existing water main pipeline will be abandoned in place. Staging would also occur in the roadway right-of-way. The terrain throughout the entire project area has been disturbed extensively by residential development, utility installations, and road maintenance.
Construction of the project would require approximately 11 months. The open trench excavation width would be up to 5 feet wide and the pipeline would be installed at depths ranging between 6 feet and 20 feet below ground surface depending on soil conditions and the location of other utilities within the project area. Trenchless drilling depths are estimated to range from 10 feet to 23 feet bgs.
A cultural resources identification study was prepared for the project in October 2020. The project would not have a significant effect on historical or archaeological resources and no adverse effect on historic properties under Section 106 of the National Historic Preservation Act. The project would adhere to regulations regarding the unanticipated discovery of human remains.
A biological resources and Coachella Valley Multi-Species Habitat Conservation Plan/Natural Communities Conservation Plan (CVMSHCP/NCCP) Consistency Analysis was prepared for the project in June 2020. The analysis determined that all special-status wildlife species with potential to occur in the survey area (which included a buffer around the Project site) are covered species under the CVMSHCP/NCCP. The project site is adjacent to the East Indio Hills Conservation Area and Thousand Palms Conservation Area designated in the CVMSHCP/NCCP. Project activities that would occur adjacent to these conservation areas would be required to implement applicable measures identified in in the Land Use Adjacency Guidelines section of the CVMSHCP/NCCP.