Big dam monitoring network East Bay Municipal Utility District safeguards critical infrastructure with intelligent GPS monitoring systems. By Angus W. Stocking, LS
Camanche Reservoir in February 2017 with the snow-capped Sierra Nevada Mountains in the background. Photo: © EBMUD, used with permission
In early 2017, Californians watched first with glee, and then horror, as drought-busting winter storms filled and then overfilled reservoirs, threatening 770-foot-tall Oroville Dam. It’s the nation’s tallest dam and impounds Lake Oroville, California’s second largest manmade lake, ca- pable of storing more than 3.5 million acre-feet. As the dam reached and then exceeded capacity, the main and emergency spillways were dam- aged, leading to the evacuation of 188,000 downstream residents. It was a sobering reminder that infrastructure matters and that infrastructure can fail. About 100 miles away, the Pardee Dam, along with Camanche Main Dam and Dikes 1 through 6, impound the Pardee and Camanche reservoirs. The two reservoirs have a total capacity of approximately 620,000 acre- feet and are the centerpiece of the East Bay Municipal Utility District’s (EBMUD) water supply system, which serves 1.4 million customers in the Bay Area’s Alameda and Contra Costa counties. (About 90 percent of EBMUD’s water supply comes from Pardee Reservoir.) These reservoirs also filled from the 2017 storms, reaching 103 percent of capacity in March, but the dams were not overtopped and releases were sustainable within the waterways. Thanks to the installation of one of the nation’s most advanced auto- mated GPS-based dam monitoring systems at these two facilities, along with other instrumentation improvements, EBMUD had the technology in place to monitor crest elevations at these dams and dikes remotely with improved temporal resolution. Having this type of data available is one more tool in an infrastructure owner’s tool belt for monitoring the condition and performance of critical facilities. “The original survey monitoring system developed in the 1960s at Camanche Dam and Dikes involved sight-lining from reference monu-
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csengineermag.com
april 2018
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