Rainbow MWD approves Warner Ranch water supply assessment

The Rainbow Municipal Water District board voted 5-0 Feb. 26 to approve the Warner Ranch water supply assessment.

The assessment indicates that the Rainbow district has sufficient long-term supplies to serve the planned development along State Route 76 approximately five miles east of Interstate 15. “Basically it says that we will supply them water,” said Rainbow general manager Dave Seymour. “The developer could use that and go to the county and show that they have water available for their project.”

The 513.49-acre project consists of seven parcels, five of which are already within the Rainbow Municipal Water District boundaries and two of which are adjacent to the water district and would likely be annexed as a development condition. When the county updated its General Plan in 2011, the Warner Ranch parcels were designated as a Special Study Area which requires a focused land use planning analysis to determine the most compatible and consistent land uses for the property.

The project as currently proposed would include 534 single-family detached homes with lots ranging from 3,000 to 8,000 square feet, 246 multi-family homes or attached townhomes, a 10,000 square foot fire station, 7.69 acres of private neighborhood parks including a clubhouse and pool, 14.68 acres of privately-maintained landscape areas, a 4.23-acre public park for active recreation, and 359.12 acres of preserved open space.

A water reservoir would be constructed on the western portion of the property and would receive water from an eight-inch water line along Jeremy Way which is currently maintained by the Rainbow district. Water would be distributed to the project through a 12-inch line connected to the reservoir. The development would fund approximately 3,000 feet of eight-inch pipeline which would be constructed from the end of the existing line to the property’s northern boundary. The off-site improvements also include a six-inch forced sewer main which would run from a new pump station on the site’s southwestern boundary to the west where it would connect with another new pump station which would be provided by the Rainbow Municipal Water District.

The project would be constructed in phases. Facilities such as the fire station, the reservoir, the sewer line, and drainage improvements are slated to be built in the initial phases.

The water supply assessment calculates an average water usage of 463,674 gallons per day, or 519 acre-feet per year. The gallons per day estimate consists of 267,000 for single-family homes, 73,800 for multi-family dwellings, 58,250 for the community landscape, 47,680 for the public and private parks, 8,000 for fire management zones, 7,674 for right-of-way and utility easements, and 1,000 for the fire station.

The water supply assessment will be used in the project’s Environmental Impact Report as well as in the county’s process to determine whether to grant a general plan amendment, specific plan, rezone, administrative permit for gated access, and vesting tentative map and in the process of water agencies to determine whether to annex the two parcels. “It’s a long drawn-out process. This is the first step of many,” Seymour said.

The county will likely require annexation of at least one of the parcels as a condition for development. (The other parcel not currently within the Rainbow Municipal Water District is designated for open space, but the desire of the Local Agency Formation Commission and the San Diego County Water Authority to avoid “islands” may result in that parcel also being added to agency territory.) “A portion of it is already within our service area, so we would just need to change our sphere of influence to include the portions that fall outside of our service area,” Seymour said.

The annexation process would not be feasible until a tentative map is approved. The parcels would also need to be annexed to the San Diego County Water Authority and to the Metropolitan Water District of Southern California, which is a complex process due to coordinating approvals, and annexation to the North County Fire Protection District will also likely be part of the LAFCO process. “They’ve got a lot more obstacles they’ve got to get past before they can start their development plans,” Seymour said.