Moses Lake water demand to outstrip supply by 2034

MOSES LAKE — If the city of Moses Lake keeps growing at its current rate, demand for water will exceed the city’s current supply, according to Jill Van Hulle, a senior water resource specialist with Aspect Consulting told the Moses Lake City Council during a special study meeting on Thursday.

“You currently have water rights for 13,104 acre-feet per year from 18 wells, and you used 9,461 in 2021,” Van Hulle said.

Currently, Van Hulle said the city’s water system serves 22,000 customers in and around the city — not all city residents are on city water — and Moses Lake is growing at a rate of 3% per year.

“At that rate, demand will exceed supply in 2034,” she said.

Aspect, a Wenatchee-based consultancy, has been retained by the city to help maintain its current water rights and seek new ones, especially in a shallow gravel aquifer about 100 feet below ground. One of the city’s 18 wells is currently drilled into that aquifer, Van Hulle said, with the city looking at developing a second shallow well.

Of the city’s other 17 wells, nine have been sunk into the Wanapum aquifer, a layer of water in basalt around 500-800 feet below the surface, and eight have been sunk into the Grande Ronde aquifer about 900-1,200 feet down. The levels of the groundwater in both the Wanapum and Grande Ronde wells are declining an average of 1 foot to nearly 20 feet per year, according to data from the city of Moses Lake, making it imperative the city find sources of drinking water.

Kelsey Mach, a water rights specialist with Aspect, said the consultancy began looking in 2020 to acquire water rights from the shallow aquifer — a large lake of underground water in gravel rather than basalt, and far more quickly and easily recharged from rainfall and snowmelt percolating into the ground than the much older water in the deeper basalt formations — from whoever might have them to sell. Right now, Mach said the city holds around 1,600 acre-feet per year of rights to shallow aquifer water and is in talks to buy another 200.

“There’s more to come,” Mach said.

Van Hulle said since around 20%-25% of the city’s summer water use is for lawn irrigation, the presence of the lake and the Moses Lake Irrigation and Rehabilitation District’s right to use 50,000 acre-feet per year for irrigation provide the city with a unique opportunity to find alternatives to drinking water from wells.

Both Van Hulle and Mach said the city should also consider acquiring a municipal and industrial water right to Columbia Basin Project water from the Bureau of Reclamation. That water would only be seasonal, but towns like Othello are already investigating treating project water and storing it underground in one of the city’s already existing aquifers for later use.

“There are a lot of questions about how feasible this is,” Mach said.

Mach and Van Hulle said water rights in the Columbia Basin retail for around $3.5 million for 1,000 acre-feet a year, and that Aspect has been doing what it can to help the city secure additional water, noting the process can be very slow and complex.

“Hiring a good water consultant is paramount,” said Council Member Mark Fancher, who said as a real estate developer he’s had plenty of experience working with water rights. “It’s not just punching a hole in the ground.”

Charles H. Featherstone can be reached at cfeatherstone@columbiabasinherald.com.

What is an acre-foot?

An acre-foot is a unit of volume equal to the volume of a sheet of water one acre in area and one foot in depth, or about 43,560 cubic feet according to the Oxford Dictionary.