San Diego plans to pay an engineering firm $100 million over the next decade to thoroughly evaluate the city’s aging dams and create a strategy to prioritize and coordinate repairs and possible rebuild projects.
The strategic plan will include proposals to shore up every dam, including cost estimates and specific timelines. It will also evaluate safety risks and how much each dam upgrade would boost reservoir capacity.
Because four city dams have been deemed safety risks, the city has been forced by the state to reduce how much water they can hold. Those restrictions have lowered the city’s reservoir capacity by 20 percent.
The plan, which city officials call a long-term strategic phasing plan, will also evaluate the accuracy of a loose city estimate that the dams require a total of $1 billion in repairs and upgrades.
That $1 billion estimate includes $275 million to build a new replacement for the Hodges Dam about 100 feet downstream from the existing dam.
City officials recently agreed to accelerate construction of the new Hodges Dam, moving estimated groundbreaking up from 2031 to 2029. Design work should reach the crucial 10 percent threshold in September, they said.
Most of the other city dams are expected to need renovations, not complete rebuilds, even though they are an average of 92 years old. But the new strategic plan could call for more rebuilds than expected.
The city’s greater attention to its dams is part of a statewide trend that began after the near failure in 2017 of Sacramento’s Oroville Dam.
San Diego’s dams are among the oldest in the state and the nation, with many nearing or surpassing the end of their useful service lives, officials said.
Nine of the city’s 11 dams pose an “extremely high hazard for downstream impacts” should dams fail while operating with a full reservoir, officials said. That means flooding, property damage and possible deaths.
Because the dams and the attached reservoirs play a crucial role in storing the city’s drinking water, costs for the renovations and rebuilds will be passed on to the city’s water customers.
But the County Water Authority, which shares ownership and maintenance responsibility for some of the dams, will share some of the costs.
The City Council’s infrastructure committee unanimously approved last month a 10-year contract with GEI Consultants. The full council is scheduled to vote on the deal July 15.
“This programmatic approach will provide a blueprint to phase in our dam safety projects methodically,” said Juan Guerreiro, director of the city’s Public Utilities Department.
The contract could pay GEI, which has completed major dam projects all across the nation, as much as $100 million. And city officials said they estimate the work will cost at least that much.
The city and some hired consultants have completed 43 of roughly 150 individual evaluations needed of the city’s 11 dams and two water storage tanks.
The evaluations include assessing the dams for seismic vulnerabilities, structural deficiencies and flood risk — how many people’s lives would be in jeopardy in the event of a partial or complete dam failure.
GEI’s help is needed despite the city creating a new division devoted entirely to dam evaluation and staffing the division with 23 full-time workers, officials said.
City officials say GEI will weigh the potential cost impact for ratepayers against safety concerns, the need to comply with state regulations and the potential impact on the city’s water supply.
Lake Murray was recently added to the list of city dams that must be kept below their maximum volume because of structural concerns, joining Lake Hodges, Lake Morena and El Capitan Reservoir.
Despite that, heavy rains last winter allowed the city to store enough water that reservoirs supplied 26 percent of the city’s water supply, up from the typical 10 percent to 15 percent.
State officials have deemed Hodges “unsatisfactory” and have rated three others as being in “poor” condition — Morena, El Capitan and Lower Otay.
Murray and Barrett got ratings of “fair,” while San Vicente, Miramar, Sutherland, Chollas and Upper Otay got the highest rating of “satisfactory.”
The city’s two large water tanks, one in Rancho Bernardo and one on Black Mountain, are also rated “satisfactory.”
Many of San Diego’s dams are outside city limits.
Lake Morena, near Campo, dates to 1912. Lower Otay, near Chula Vista, opened in 1916. Lake Hodges opened in 1919. Murray, near La Mesa, opened in 1918. Barrett, near Jamul, opened in 1922.
El Capitan, near Lakeside, opened in 1935. San Vicente, also near Lakeside, opened in 1943. Sutherland, in Ramona, opened in 1954. And Miramar opened in 1960.
