Hilary's aftermath: Palm Desert OKs $4.6M contract to expand flood retention basin along I-10
About four months after Tropical Storm Hilary dropped several inches of rain and wreaked havoc on parts of the Coachella Valley, the Palm Desert City Council approved a $4.63 million contract for upgrades and an expansion of a major retention basin just south of Interstate 10.
The council unanimously approved the contract with The Van Dyke Corporation, along with a few other steps to continue the city’s post-storm response, during its meeting Thursday.
Tropical Storm Hilary had widespread impacts when it struck the valley in August, causing major flooding in Cathedral City and elsewhere. Much of Palm Desert was relatively unscathed from the historic storm, but Hilary caused major damage to the city’s Spanish Walk neighborhood, displacing a handful of residents and filling some homes with mud and floodwater.
The mud and flooding that came into parts of Spanish Walk were caused by overflowing from a mid-valley diversion channel that starts just west of Palm Desert and extends through the city, running alongside the Union Pacific railroad and Interstate 10.
The contract approved by the council Thursday will expand the capacity of a retention basin just west of the Spanish Walk neighborhood that connects with the mid-valley channel. The basin, which runs along Interstate 10 north of Dinah Shore Drive and Portola Road, is located on a parcel of land known as Section 29.
City officials were working to evaluate and expand the channel even before Tropical Storm Hilary struck in August. In March 2022, the city hired an engineering firm to evaluate the basin.
The engineering team found that based on the basin’s current physical capacity of 45.4 acre-feet, another 16.3 acre-feet of retention volume would reduce the risk of overflows and provide the storage necessary for a 100-year storm event, according to a council report from Project Manager Lucero Leyva. (An acre-foot is approximately 326,000 gallons.)
The roughly 36% capacity expansion of the Section 29 retention basin is expected to take several months. City spokesperson Thomas Soule said Friday the best estimate is the project will be completed by the end of August 2024.
More: A month after Hilary, people in hard-hit Palm Desert neighborhood still looking for help
The roughly $4.63 million approved for the basin’s expansion is in addition to $5.05 million the city council has budgeted for its initial storm response, as well as upgrades to the mid-valley channel’s infrastructure. President Joe Biden also recently approved an emergency declaration related to Tropical Storm Hilary, so city officials are now working to maximize FEMA assistance and reimbursements.
As a result of the storm, the city is also working on a maintenance and repair project that involves assessing and cleaning the mid-valley channel from Monterey Avenue to Washington Street. The project will also involve cleaning culverts along the Whitewater River channel at Cook Street, as well as other infrastructure impacted by the storm.
Contractor proposals for that project are due in early January. Given the city council’s winter break and the possibility of rain in the near future, the city council also voted Thursday to allow City Manager Todd Hileman to award contracts to qualified vendors, not to exceed a total of $2 million. That money will largely come from the $5.05 million already approved by the city council, along with another $500,000 appropriation.
Tom Coulter covers the cities of Palm Desert, La Quinta, Rancho Mirage and Indian Wells. Reach him at thomas.coulter@desertsun.com.
This article originally appeared on Palm Springs Desert Sun: Tropical Storm Hilary: Palm Desert OKs $4.6 million to expand flood retention basin
