PALMDALE — The Palmdale Water District looks to take the next step in its years-long project to remove sediment from the reservoir behind the Littlerock Dam and increase its water storage capacity.
On Monday, the Board of Directors will consider a $1.6 million contract with Aspen Environmental Group for work involved with the design, permitting and construction of the project over the next three years, with potentially two years after that.
The Littlerock Reservoir Sediment Removal Project has been in the works for more than 25 years. The project calls for removing more than 1.16 million cubic yards of sediment that has built up behind the dam since 1992, reducing the water storage capacity by 500 acre-feet, according to District officials.
An acre-foot is 325,851 gallons, or approximately the amount of water a typical Antelope Valley household used in one year, before the last drought reduced usage.
The reservoir collects rain and snow melt from the watershed in the San Gabriel Mountains, and is one of three sources of water for the District. The others are groundwater pumped from wells and State Water Project water carried through the California Aqueduct.
The first phase of the project was construction of a subterranean grade control structure, which began in October 2018 and was completed early last year.
The grade control structure was required before sediment removal may begin, in order to shore up the ground to prevent erosion once sediment is taken out of the stream.
The next phase of the project will involve renewing permits with the California Department of Fish and Wildlife, Lahontan Regional Water Quality Control Board and the US Forest Service.
It will also include designing the grading plans for removing sediment over a three-to-five-year period, to be updated every year, according to the staff report.
The consulting contract includes these services, plus providing biological and construction inspection.
Aspen Environmental Group was one of two companies with qualified proposals for the project in answer to a request for proposals from the District. They were chosen for recommendation to the Board based on experience, availability and lower proposed fee by almost $740,00, according to the staff report.
The firm has already been working with the District on earlier aspects of the project, including biological surveys and the biological assessment in regards to the endangered arroyo toad. Last year, they assisted in the emergency sediment removal due to debris from the Bobcat Fire, by conducting surveys, reviewing plans and obtaining permits, according to the proposal.
The Board meeting begins at 6 p.m. and is available to the public through teleconference only. The dial-in number is 571-748-4021; Attendee pin: 923-073-515#
Public comments may also be submitted at https://www.gomeet.com/923-073-515