WaterWatch4C

PALMDALE — The Antelope Valley Watermaster gave preliminary approval to the first two water storage agreements to come before the Board tasked with overseeing the 2015 court settlement that set limits on groundwater pumping for users across the Valley.

The Watermaster Board reviewed applications from the Rosamond Community Services District and the Littlerock Creek Irrigation District regarding projects that would, in effect, store water underground in the aquifer by allowing it to percolate through the soil. It may then be withdrawn in the future through wells.

The storage agreements with the Watermaster are required for the districts to get credit for the water recharged into the aquifer, which will, in turn, impact how much groundwater they are allowed to pump.

The Board, on Sept. 25, granted preliminary approval to the water storage applications; the full legal agreements will be brought back at a later date for final approval. Because these were the first two such agreements presented to the Board, the legal language had not yet been finalized, Watermaster Engineer Phyllis Stanin said.

Both applications required review by the engineer under contract to the Watermaster to ensure the projects would not harm the underlying aquifer.

The Rosamond project is part of a plan to meet a requirement to reduce excess nitrates seeping into the ground­water from water treat­ed to a secondary level at the wastewater treatment plant. The treat­ed water is currently sent to evaporation ponds on site.

Instead, the district will take the secondary-treated ef­flu­ent, run it through the somewhat modified ter­tiary treatment equipment to remove nitrates, then percolate the resulting water into the ground. The application seeks credit for that percolation into the groundwater.

“This is a really great recycling wastewater

project,” Stanin said.

The agreement has conditions set by the Watermaster, which the District must meet, for approval. These conditions mirror those required by the Lahontan Re­gion­al Water Quality Control Board, which issued the order for the District to reduce the excess nitrates. The Watermaster agreement just asks to be included in the reporting, Stanin said.

“We don’t want to provide an additional level of regulatory effort after they are already compliant with requirements from the regional water quality Board,”

she said.

Watermaster Board Chairman Rob Parris said it’s a creative project and one that they’re very interest in, but one they want to be fully knowledgeable about before they

approve it.

“I think we need to move slowly on this and have all the information before us before we approve it,”

he said.

With the design of the project, calculating the amount of water to credit for storage “is a little bit easier,” Stanin said, as there is some certainty of the timing and flow into the percolation ponds. “It’s a relatively straightforward

calculation.”

There are losses associated with underground water banking, which is set at a standard 10% for the Watermaster purposes.

The Littlerock Creek Irrigation District’s project would take State Water Project water straight from the California Aqueduct via an existing turnout and flow it into a recharge basin just east of Littlerock Creek with a bottom area of about 1.2 acres and sloping sides.

“It’s a good place for getting water into the ground,” Stanin said.

The imported water would percolate into the groundwater basin through this recharge basin, and be recovered in the future using existing wells.

Concerns regarding the project included the interaction of the imported water recharge with natural recharge in Littlerock Creek, an important feature of the groundwater basin.

“We wanted to make sure that natural recharge did not prevent the project from storing water and that the stored water did not prevent recharge from occurring from natural systems,”

Stanin said.

Analysis alleviated the concerns, and “everything looks good from a hydro-geologic standpoint,” she said.

However, the project should be monitored to ensure this stays true, she said, conditions that the District agreed to follow.

“We feel comfortable that the project will not create any issues of material injury,” given the

monitoring, she said.

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