Wohlford Lake Dam replacement ‘shovel-ready’
The town of Escondido plans to replace the Lake Walford Dam, a structure made of earth 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 city-owned. The lake has long served the city as a recreational asset for boaters and fishing enthusiasts, and as an emergency reservoir for the supply of drinking water in times of drought.
Almost 10 years after planning, design work and environmental reviews, once funds are available the project is ready to move forward, said Christopher McKinney, deputy mayor and director of utilities at Escondido.
“The replacement dam is ready for a shovel,” McKinney said.
About 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 area to 225 acres, according to environmental documents.
However, a 2007 state safety inspection found that adding 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 past 14 years.
The city’s current plan is to build a new dam about 300 meters 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 intact and submerged below the surface of the lake.
According to McKinney, construction of the new dam will take around two years and the city hopes to begin construction in early 2022.
One of the problems facing municipal authorities is the increasing cost of projects. The original estimate for the 2012 project was $ 30 million for construction. According to McKinney, that figure more than doubled to $ 72 million, including some restructuring of Oakvale Road.
Road readjustments will take place before the dam is built, and bids for construction could be submitted to 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 expand grant eligibility.
The city is also working on a final decision on federal grants and low-interest federal loans to cover most of the project’s remaining costs, McKinney said. Depending on the amount the city receives as part of the grant, the loan amount will be adjusted to keep its source of funding as low as possible. The city also secured $ 16 million in capital reserves allocated to the project.
“I’m happy to say I’m optimistic that all three sources will eventually pay off,” McKinney said. “With all three (funding sources) and our money, we can make this project a success.”
Last year, in light of increasing 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 modification and construction of new dams in California. ..
“Unfortunately, we haven’t found a better alternative than building a new dam,” McKinney said. “We refocused on the exchange. It was clear that this was the most viable option. “
When the new dam is built, the city will be able to bring the lake back to its full level, helping to improve water quality, increase the lake’s storage capacity and increase the area of the lake for recreational users. McKinney said. I go.
The city is also working with the California Department of Fish and Wildlife (CDFW) to manage the impact on wetland habitats around the lake.
During an environmental review of the project, authorities feared that the wetlands formed when the lake fell in 2007 would be flooded when the lake’s water level returned to its full height. In response, McKinney said the city has agreed to raise the lake’s water level more slowly, allowing new wetlands to form as existing habitats submerge. The agreement significantly reduced the cost of mitigation.
Jennifer Turner, senior environmental scientist / supervisor at CDFW’s San Diego office, is concerned about several species of flora and fauna that may be affected by the dam exchange project, including Engelmann Oak, Golden Eagle, Mountain Lion and Deer. He said he was doing it. The CDFW also wanted to ensure that invasive and non-native species such as the red-eared gladiator and the bullfrog were controlled.
Before the city could proceed with the project, Turner said it needed to enter into a lakes and rivers modification agreement with CDFW “to meet the needs of the project and avoid affecting as much flora and fauna as possible.” . It was.
McKinney said transactions with regulators in both states are on track.
Wohlford Lake Dam replacement ‘shovel-ready’ Source link Wohlford Lake Dam replacement ‘shovel-ready’