Lake Hodges Dam faces additional repairs due to discovery of new defect

Repair work continues on Lake Hodges Dam.
(Karen Billing)

The ongoing emergency repairs to the Lake Hodges Dam will need to be expanded as recently a hole was uncovered at 285 feet. The extent of the damages was made apparent in mid-August due to the lowered water level and the discovery will delay the completion of the project by several months.

“Our top priority must be preserving the integrity and safety of the 104-year-old Hodges Dam and the surrounding communities,” said San Diego City Councilmember Marni von Wilpert, who represents District 5 in a news release. “While I understand that this news is frustrating, public safety and dam integrity must not be compromised and I thank the Public Utilities Department for their diligent work.”

The initial schedule had the refilling of the reservoir to 293 feet by the end of October. With the adjusted timeline, the work is now expected to continue into spring 2023. What started with an emergency repair budget of $6 million has now escalated to $10.1 million with this latest discovery.

Drew Kleis, the interim assistant director of the water delivery branch for the San Diego Public Utilities Department, shared the latest updates on the dam repairs at the Santa Fe Irrigation District’s Sept. 15 meeting.

The Lake Hodges Dam was constructed in 1918 and the reservoir provides water supply for the County Water Authority, San Dieguito Water District and the Santa Fe Irrigation District, which serves Rancho Santa Fe, Fairbanks Ranch and Solana Beach.

During an inspection earlier this year, the city found there was water leakage as well as concrete chipping away on the face of the dam, exposing rebar which was decaying. In March 2022, the city performed an underwater assessment and what they found was concerning, prompting the need for immediate repairs.

To complete the repairs required the water level to be lowered 18 feet to an elevation of 275 feet by transferring water to other reservoirs and treatment plants. As crews continued with repairs using floating barges, new issues were exposed on the dam face, including the hole. This was concerning to the Division of Safety of Dams (DSOD), who issued a letter in mid-August recommending that there be a temporary height restriction—the DSOD requires that the water be raised no higher than 285 for repairs and that it be back to 275 feet by Nov. 30 to avoid putting water pressure on the defect.

Kleis said the city is now required to conduct a consequence analysis and structural modeling analysis to determine at what height level would result in zero loss of life in the event of failure. The analysis is expected to be complete in November.

“There’s no question that with a dam that is 104 years old, it’s reaching the end of its useful life,” Kleis said. “We are also working in parallel with DSOD in evaluating potential replacement options or rehabilitation options for this dam.”

As crews won’t be able to raise the elevation of the floating barges as high, the revised plan for the dam repairs now includes additional rappelling work, which Kleis said is less efficient and will extend the construction time. The repairs are now anticipated to be complete by February 2023 and result in an additional cost of $1 million.

The adjusted water level could impact the ability to store water—water will need to be released below the dam if there is a rain event this coming winter.

SFID Director Andrew Menshek said in touring the dam a couple months ago, it was obvious to him that the damage has been going on for probably decades. He questioned the city’s preventative maintenance and if any below-level water inspections had previously been done. Kleis said the underwater inspections occurred only recently but staff does perform maintenance and visual inspections regularly at all nine city reservoirs.

Menshek wanted to state his concerns on the record about the current situation.

“We have based our budget projections on utilizing and having access to a certain number of acre-feet per year. Since that has been drastically cut and the unknowns with DSOD and the repairs, that’s going to adversely impact our water rates and our customers. It’s for the best because I am concerned about downstream issues should we have any failure of any magnitude,” Menshek said. “But having signed that contract I was always under the impression as a director that there had been ongoing maintenance provided and inspections and now just from what I’m seeing…there hasn’t been that maintenance done on that dam which is now going to impact our access to water, impact the safety downstream and also going to increase our costs for the repairs and I’m pretty sure we’re probably going to be looking at a new dam.”

As a result of the lower water level, Hodges Reservoir has been closed for boating and fishing since the project began. The San Dieguito River Park trails and facilities around Hodges Reservoir have remained open to the public during the drawdown.

The city is looking at ways it could restore some water recreation activities in the coming months but the concern is that the mud line is unsafe—in June San Diego Fire Rescue crews had to rescue two people by helicopter who got stuck in the mud along the bank.