The first load of sediment was removed recently from Littlerock Dam to begin a Palmdale Water District project that was postponed in the early 1990s when the federally protected arroyo toad was discovered in the area.
The Littlerock Sediment Removal Project is a 12-year plan to restore the dam to its 1992 water storage capacity of 3,500 acre-feet. Currently, the capacity is at 2,800 acre-feet due to years of sediment buildup.
“This is a momentous occasion for PWD,” said General Manager Dennis D. LaMoreaux. “For almost 30 years, we have been waiting to restore it to its capacity. We’ve hit hurdles that were beyond our control and spent millions to meet requirements. This is a good day.”
Innovative Construction Solutions of Costa Mesa is the contractor removing 64,000 cubic yards of sediment from the reservoir and trucking it to a local gravel pit. The company has experience working at Littlerock Dam, having removed sediment in early 2021 after the Bobcat fire caused a buildup of debris. If the weather remains favorable, this year’s phase of the project should be completed in five weeks.
Cost of this sediment removal is $2.8 million, with $1.1 million coming from grants. Although the multi-year project initially called for the annual removal of 120,000 cubic yards to total 1.1 million cubic yards within 12 years, the total accumulation has now grown to 1.7 million cubic yards.
The project was finally given the green light in 2020 after a $14 million grade-control structure was built at Rocky Point. At 400 feet wide and 240 feet long, it is a staircase-designed structure that prevents erosion and protects the toad’s upstream habitat during sediment removal.
“After three decades of delay, it’s nice to finally see this project move forward with the removal of sediment,” said Engineering Manager Scott Rogers. “Our plan is to stay within our budget and seek out grant funding opportunities to help with this annual cost.”
“It is important that we restore the reservoir to its maximum water capacity, especially as we continue to face severe drought and more local water supply storage is needed,” Rogers added.