The Miramar Water Treatment Plant, situated on the shore of Lake Miramar, is the sole provider of drinking water to an estimated 500,000 customers in the northern section of San Diego. The reservoir is a popular community recreational site. Since the facility and associated equipment, such as valves, pipes and controls, were approaching the end of their useful life, the City needed to expand the plant capacity from 140 MGD to 215 MGD to meet existing and future water demand. Facility upgrades consisted of a new rapid mix facility; installation of new aeration basins and disinfection facilities; new chemical facilities; new and refurbished administration facilities; flocculation and sedimentation basins; a wash water recovery system; and water filters. The new state- of-the-art facility is projected to have a useful life of 75 years. The total cost for the entire upgrade over $135 million.
Beyaz & Patel was responsible for the structural design, drawings and specifications for the ozone facilities, filters, rapid mixing structures, flocculation and sedimentation basins, and operations buildings. During construction, we visited the site to answer questions and to ensure that structural elements were being built as designed. We also conducted a seismic evaluation of the plant and assessed the structural condition of Clearwell No. 2 Reservoir, which was an aging rectangular covered 30 Mg concrete reservoir. Our seismic analysis was performed based on Seismic Zone 4, using the 1997 UBC, ACI 350, NEHRP Standards, and Miramar Structural Design Criteria. Two options were considered for retrofitting the reservoir along with order-of-magnitude cost estimates and retrofit recommendations. A composite carbon and glass fiber- strengthening method was selected.