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Otay Reservoir Spills Over Its Dam For The First Time Since 2011

Reported by Megan Burks

The Lower Otay Reservoir spilled over its dam Tuesday for the first time in six years because of Monday's heavy rainfall.

The Lower Otay Reservoir spilled over its dam Tuesday because of Monday's heavy rainfall, the city of San Diego reported Tuesday.

The reservoir crested and began to spill into the Otay River Valley, but no downstream danger was anticipated, city spokeswoman Alma Rife said.

This isn't the first time the dam has spilled over. Water flowed through its floodgates in 2011 after above average rainfall. And the dam breached back in 1916, the water washing away farmlands and taking some lives with it.

Photo by Megan Burks

A fish spills through the floodgates on the Lower Otay Reservoir dam, Feb. 28, 2017.

That incident came after city leaders — desperate from four years of drought — hired a rainmaker. That winter the region saw 30 inches of rain.

This time around, the dam is in working order. The water is expected to wind through the Otay riverbed and spill into the Pacific.

"The reservoir serves as a terminal reservoir for a significant-sized watershed, imported water aqueducts and a source of local water for the Otay Drinking Water Treatment Plant," Rife said. "For these reasons, the reservoir intentionally operates at a higher capacity level than many of the other city reservoirs which are used primarily for storage and rely on local rain and snow runoff."

According to city records, the reservoir can hold nearly 49,849 acre feet of water, and on Monday, it was reported to have been at more than 93 percent of capacity.

The National Weather Service recorded more than 2-3 inches of rain Monday in the South Bay area.

Rife said no other city-operated dams were spilling. The only others even close to capacity in Monday's observations were Lake Murray at almost 88 percent, and Miramar at nearly 85 percent.

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