Floating Cover for Potable Water Reservoir

LOCATION: Pacific Palisades, CA TIMEFRAME: January 2011 – June 2011 SCOPE OF WORK: Furnish and install 45 mil CSPE custom color floating cover system, chaffer strip, and cover appurtenances PROJECT PARTNERS: Owner: Los Angeles Department of Water and Power Client: LADWP Installation: Layfield Environmental Systems Corp Material supplier: Burke Industries

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The 41 year old Santa Ynez Reservoir in Pacific Palisades California was an open water reservoir; up until recently when the Los Angeles Department of Water and Power decided to cover the reservoir in order to conserve water, decrease water contamination and switch from using chlorine to chloramines to treat the water. The reservoir is situated on about 9 acres of land and is approximately 70 feet deep. When full it will hold nearly 120 million gallons of potable water and will serve both Pacific Palisades and the Highlands. The reservoir also functions as an emergency water resource for fire crews during Southern California’s fire season. This put a strict requirement on the timeline of the project and the amount of time the reservoir was allowed to be offline.

The Santa Ynez Reservoir is tucked between two mountains in the Topanga State Park just north of Santa Monica, CA. The reservoir is overlooked by thousands of homeowners in an upscale neighborhood. The surrounding community was very concerned with the visual appearance of the reservoir as this is a main focal point for most of them. In order to cover the Reservoir the LADWP had to meet several challenging requirements that were set forth by the Pacific Palisades Community Council and several local homeowners.

Originally, it was specified that the Reservoir would be covered using a Hypalon material made by Burke Industries from Dupont resin. A major challenge was thrown at Layfield, the installer, and the Project Engineers when Dupont unexpectedly decided to stop making the resin used to produce Hypalon.


In order to meet the stringent visual requirements set forth by the community, the LADWP worked with Burke and Layfield to find a custom material color that would blend in with the surroundings. Burke Industries produced several large samples of material in different colors. These were reviewed by the community and a green/black camouflage color was chosen.

The Dupont closure came as a surprise to everyone involved with the project. Burke and Layfield had to work quickly to get a new material specified and approved by the Project Engineer. There were a couple of options offered to the Engineer and the choice was made to use a Chlorosulfinated Polyethelyene (CSPE) Resin to produce the material.

Layfield received the CSPE cover material from Burke Industries and fabricated it into large cover panels – over 600,000 SF of cover material was needed to cover the reservoir. There was also a chaffer strip placed around the perimeter of the reservoir to prevent the cover from chaffing on the asphalt below as the water level raised and lowered the cover. In all, nearly 1 million SF of 45 mil CSPE material was used to complete the project. The project also included the installation of several cover appurtenances. Among these were thirteen access hatches on the cover, to allow access for divers and to sample water quality. Three equipment hatches were installed so that two large mixers, placed at the toe of the slope could be removed in the future for any necessary service required. A textured walkway was installed on the cover over a ramp to allow the LADWP operations department easy access onto the cover surface. A system of sand tubes and CSPE covered floats were installed to create a defined sump along the toe of the slope and extending out into each corner of the reservoir. Six rainwater removal pumps were installed inside pump housings that were placed in the sumps to remove any rainwater from the covers’ surface. There were also sand tube strap assemblies, buffer strips, large and small cover vents, and an overflow flap gate installed in the reservoir.


The Santa Ynez Reservoir was completed in time to bring it back online for Southern California’s fire season, the community expressed their approval of the final appearance of the project and LADWP added another covered potable water reservoir to their portfolio.
When it was finished in June 2011, the Santa Ynez Reservoir was a highly customized and visually attractive Reservoir, it also became the first Potable Water Reservoir in the United States to be covered with a custom camouflage colored CSPE material.