Water Engineering

Rancho Bernardo Reservoir Rehabilitation | San Diego, CA

City of San Diego


Civil Engineering
Seismic Design


ASCE – Award of Merit
AWPA – Honorable Mention
APWA – Honor Award

Extending Old Reservoir’s Useful Life by 30 Years

Originally constructed in 1964, the Rancho Bernardo Reservoir is a 10 MG, 83,000 SF earthen embankment reservoir. The original 2:1 side slopes and floor were lined with porous asphalt and rubber butyl. The original roof system consisted of a post-tensioned concrete roof slab supported by reinforced concrete columns, beams, girders and perimeter wall.

Corrosion and deterioration was causing concern about its longevity as a reliable storage facility. In addition, the structure no longer complied with current seismic standards. Psomas was retained to study and design improvements.

After investigation, the decision was made to demolish the entire roof system including slabs, beams, girders and columns along with the perimeter wall and floor. The reservoir was given a new aluminum roof with stainless steel columns, new concrete floor, asphalt side slopes and perimeter wall. The interior of the reservoir was lined with a 60 mil Hypalon liner. New mixer piping, chlorination piping, motor operated plug valve, chlorine analyzer, sampling station, motor operated ball valve, mud valve, ultrasonic level sensor, drain outlet, valve vault hatch door have been installed. The useful life of the reservoir has been extended another 30 years.