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Rainbow Municipal Water District Reservoir Project Selected for Award

The Rainbow Municipal Water District’s (RMWD) Morro Reservoir Rehabilitation Project (2010-2012), performed by Hilts Consulting Group of Yorba Linda, CA, was selected for the inaugural Fabricated Geomembrane Engineering Innovation Award in 2016.  The award was presented by the Fabricated Geomembrane Institute at the University of Illinois at its annual membership meeting in Miami Beach, Florida, in early May of last year.  The award is given to recognize engineers who have creatively used fabricated geomembranes to successfully fulfill a client’s need, including technical, scheduling and budget requirements.

RMWD General Manager Tom Kennedy commented, “We were thrilled to learn of this award to our contractor on this project.  They helped us develop and install a system that not only assures the district is within code compliance, but more importantly provides us with better operational efficiencies while assuring the quality of the water we provide our customers.”

RMWD’s Morro Reservoir was originally constructed in 1964 and has a maximum storage capacity of 151 million gallons with a 12.5-acre surface area.  The man-made reservoir has a maximum depth of 60 feet with side slopes being 2:1 (horizontal to vertical).

The project was required to comply with the Safe Drinking Water Act, which in general requires the reservoir to be covered or provide treatment on the reservoir outlet.  The floating cover construction was slightly more than $8 million.  As part of the same project, RMWD also decided to upgrade the reservoir liner to further protect the potable water.  A composite geomembrane liner was installed to reduce seepage of water through the bottom of the reservoir.  The liner also enhances the maximum allowable drawdown rate for the reservoir. 

The floating flexible cover protects the drinking water quality, provides a barrier to wind driven contaminants, reduces evaporation, and reduces overall use of chemicals.  It is equipped it access hatches, automated drainage system to remove rain water as well as automatic pumps and blowers to remove air trapped between the cover and water surface.  It requires regular maintenance, inspections and periodic cleaning to assure proper operation and care.  On site security systems ensure that unauthorized access is detected and deterred.

This project is an example of RMWD’s commitment to its rate payers to provide both a safe supply of quality water and efforts to increase efficiency of its infrastructure.  These efforts help the district to keep rates at the lowest possible levels.