Replacement of Lake Wohlford dam is ‘shovel ready’

The city of Escondido is planning to replace the Lake Walford Dam, a structure made of soil and rock that has stood in its current location since 1895.

Lake Wohlford is about five miles northeast of downtown Escondido, just beyond the unincorporated area of ​​San Diego County, and the dam is owned by the city. The lake has long served the city as a recreational asset for boaters and fishing enthusiasts, and as an emergency reservoir for supplying drinking water in the event of a drought.

Almost 10 years after planning, design work and environmental reviews, once the funds are available, the project is ready to proceed, said Christopher McKinney, Deputy Mayor and Utility Director of Escondido.

“The replacement dam is ready for a shovel,” McKinney said.

Approximately 30 years after the first dam was built, the city pulled up and expanded the dam in 1924, increasing its water storage capacity to about 6,500 acre feet and its surface area to 225 acres, according to environmental documents.

However, a state safety inspection conducted in 2007 found that the addition of dams could cause catastrophic damage in earthquakes of magnitude 7.5 and above. As a safety measure, the city has lowered the water level to the height of the original dam and reduced its storage capacity by more than half over the last 14 years.

The city’s current plan is to build a new dam about 300 yards downstream or west of the existing dam, McKinney said. The new dam will be constructed with a layer of concrete spread from bottom to top. When the new dam is complete, remove the top of the old dam and make a cut in the old dam to allow water to flow through the new structure. Most of the old dam is left untouched and submerged under the surface of the lake.

According to McKinney, the construction of the new dam will take about two years, and the city hopes to begin construction in early 2022.

One of the problems facing city authorities is the rising cost of projects. The initial estimate for the 2012 project was $ 30 million for construction. According to McKinney, this figure more than doubled to $ 72 million, including some restructuring of Oakvale Road.

Road readjustments will take place prior to dam construction, and bids for the construction may be submitted to the city council soon this month, McKinney said.

According to McKinney, the city is considering three external sources of funding to replace the dam. The first is a $ 15 million state grant that has already been approved, but legislative approval is required to extend the grant’s eligibility.

The city is also working on a final decision on federal grants and low-interest federal loans to cover most of the remaining costs of the project, McKinney said. Based on the amount the city receives in the grant, the loan amount will be adjusted to keep its funding source as low as possible. The city also secured $ 16 million in capital reserves allocated to the project.

“I’m happy to say that I’m optimistic that all three sources will ultimately bear fruit,” McKinney said. “With all three (sources of funding) and our cash, we can complete this project.”

Last year, in light of rising project costs, the city considered alternatives to building new dams, such as rehabilitating existing dams to meet current seismic safety standards. However, McKinney said these alternatives are too expensive and unlikely to be approved by the Dam Safety Department, a regulatory body that must approve the modification and construction of new California dams. ..

“Unfortunately, we haven’t found a better alternative than building a new dam,” McKinney said. “We refocused on the exchange. It was clear that it was the most viable option.”

When the new dam is built, the city will be able to bring the lake back to full levels, helping to improve water quality, increase lake storage capacity and increase the surface area of ​​the lake for recreational users, McKinney said. I will.

The city is also working with the California Department of Fish and Wildlife (CDFW) to manage the impact on wetland habitats around the lake.

Authorities were concerned during an environmental review of the project that the wetlands formed when the lake fell in 2007 could be flooded when the lake’s water level returns to full height. In response, McKinney said the city agreed to raise the lake’s water level more slowly, allowing new wetlands to form as existing habitats submerge. The agreement has significantly reduced the cost of mitigation.

Jennifer Turner, senior environmental scientist / supervisor at CDFW’s San Diego office, is concerned about several flora and fauna species that may be affected by the dam exchange project, including Engelmann Oak, Golden Eagle, Mountain Lion, and Deer. He said he was doing it. CDFW also wanted to make sure that invasive and non-native species such as the Red-eared Slider and Bullfrog were controlled.

Before the city can proceed with the project, Turner said it needs to complete a lake and river modification agreement with CDFW “to meet the needs of the project and avoid affecting as many flora and fauna as possible.” It was.

McKinney said transactions with regulators in both states are on track.

Replacement of Lake Wohlford dam is ‘shovel ready’ Source link Replacement of Lake Wohlford dam is ‘shovel ready’

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