Photo via

 The Vallecitos Water District received two awards for its innovative use of technology to reduce algae blooms at Mahr Reservoir, it was announced Thursday.

The district received the “Excellence in Action” national award from the WateReuse Association and the “Innovation and Resiliency” state award from the California Association of Sanitation Agencies for its use of an ultrasound technology to address water quality at the Stanley A. Mahr Reservoir with a reduced need for chemical treatment.

The most common method of treating algal blooms is with chemicals. VWD instead uses technology developed by the international company LG Sonic, which provides an overview of the water quality allowing identification and treatment of algal blooms.

“This award is proof of the Vallecitos Water District’s commitment to innovation,” said Mike Sannella, Vallecitos board president. “District staff are to be commended for their efforts to use innovative technology to improve and enhance our operations.”

Every 10 minutes, a buoy in the reservoir measures and monitors green and blue-green algae population, pH, turbidity, dissolved oxygen and water temperature. The data are collected in real time and uploaded to a web-based software. The software uses the data to predict algal blooms three to 10 days in advance.

The LG Sonic buoy can create a sound barrier in the top water layer, which affects the buoyancy of the algae, preventing it from rising where it can absorb sunlight for photosynthesis to grow.

Without sunlight and nutrients, algae cells sink to deeper water where they degrade due to natural bacteria and do not release toxins into the water. With overall algae levels reduced by this technology, the need for chemical treatment is also reduced, allowing the district to provide reclaimed water to its customers.

Originally called La Costa Storage No. 1 Dam and Reservoir, Mahr Reservoir was renamed after VWD’s founder, 35-year board member Stanley A. Mahr. It stores up to 54 million gallons of reclaimed water to be used later for irrigation and was completed in 1981.

The VWD has contracts with Carlsbad and Olivenhain Municipal Water District to provide water as needed, as much as five million gallons of recycled water daily.

Because the reservoir receives intense sunlight with little rain, algal blooms can occur in the nutrient-rich recycled water.

–City News Service