Project Background

The Water Authority built a new flow regulatory structure to upgrade the untreated water system in the northwest area of Mission Trails Regional Park. The project, completed in May 2023, upgraded the untreated water system that delivers water to treatment plants that serve the central and southern areas of San Diego County.

The underground flow regulatory structure, or covered reservoir, was constructed to help regulate the water system’s flow of untreated water. It can hold up to five million gallons of untreated water. The facility is covered with soil and vegetation, with the exception of access hatches and above-ground vents to allow for air movement in and out of the reservoir.

The work was part of a suite of projects within the Mission Trails 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.