The Water Authority is building a new flow regulatory structure to upgrade the untreated water system in the northwest area of Mission Trails Regional Park. When complete, the project will upgrade the untreated water system that delivers water to treatment plants that serve the central and southern areas of San Diego County.

Construction is taking place Monday through Friday between 7 a.m. and 7 p.m. and will close some trails in the western portion of the park. Trail closure signs, including a park map showing alternate trails are posted to help park users navigate the trails.

The project currently underway will construct a new 5-million-gallon underground covered reservoir, a flow control facility and pipeline interconnections. The reservoir will be covered with soil and vegetation, except for several access hatches and vents that allow for air movement inside the reservoir.

This work is part of a suite of projects called the Mission Trails Project located in the western portion of the park. In 2010, a new pipeline tunnel, removal of existing blue vent stacks and a new all-weather crossing of the San Diego River was completed. Construction of the flow regulatory structure portion of the project was planned to begin soon after but was delayed by the Water Authority’s Board of Directors in early 2011, citing increasing water rates due to lower water demands.

The contractor set up work areas in March and started construction in April. Work is scheduled to be complete in early 2022.

Nearby residents will see an increase in construction traffic on Clairemont Mesa Boulevard, Calle de Vida, Portobelo Drive and Antigua Boulevard as well as in and near the western portion of Mission Trails Regional Park. Construction vehicles will use park trails to access work areas.

Prior to starting construction, the Water Authority conducted habitat management activities that allowed the safe and humane relocation of small mammals and amphibians outside the work area. This work was in accordance with federal and state environmental permits to help protect and preserve sensitive species. Environmental fencing placed around work areas closed off trail access in these areas to prevent animals from returning to the work areas.

For more information about the project and to access maps of closed trails with alternate routes, visit sdcwa.org/mission-trails-FRS.