Robert B. Diemer
Filtration Plant

Yorba Linda, CA

In 2002, MWA developed a master plan and design guidelines for the Metropolitan Water District of Southern California’s (MWD’s) Robert B. Diemer Filtration Plant, a 520-million-gallons-per-day clean water treatment plant located at the junction of Orange, Los Angeles, and Riverside counties.

In 2005, we provided design development, detailing, documentation, and construction administration for several new facilities in the Oxidation Retrofit Program, including the new, two-story ozone building with lobby, control room, ozone generator room, and support spaces; the new ozone contactor building; switchgear building; emergency generator building; liquid oxygen facility; and solids handling facility.

The ozonation buildings contain water treatment processing areas, administrative offices, laboratory spaces, chemical storage, and public galleries. The galleries allow visitors to see inside the generator building’s operational areas safely and securely.

Diemer sits on top of an 800-foot hill, visible from miles away. Surrounding the site are new and established residential communities and a State park. MWD's primary concern, after achieving a functional plant design, was to maintain good neighborhood relations. MWA placed most of the new construction downhill from the main plant in a valley, or in line with existing construction to reduce its overall visibility.

Using our new design guidelines, we prepared a series of recommendations to aesthetically organize the site’s new and existing buildings. We developed a contemporary architectural language for all new buildings onsite—even those designed by other architects. The original buildings were constructed of reinforced concrete in a late Art Deco style. While MWA did not replicate that style for the new buildings, we did incorporate some concepts, such as expansive overhangs.

Client: Metropolitan Water District of Southern California
Cost: $195 million
Completion: 2014

Photos: Tom Bleicher