Proposed pipeline would deliver water to farmers east of Moxee

A private water bank isn’t the only project in the Selah-Moxee Irrigation District that aims to improve water availability there.

The district also is proposing a 10-mile pipeline to divert water from the Yakima River to farmers east of Moxee.

The intent is to reduce farmers’ reliance on groundwater in the Black Rock area, where aquifers have been declining as much as 13 feet a year the past several years, according to a water marketing study.

The proposed $84 million pipeline that would include a 3,500 acre-foot reservoir will be briefly discussed during a 6 p.m. open house the irrigation district is having Thursday at the Yakima Area Arboretum. The district’s private water bank will be the focus of the open house.

“It’s more about taking demand off groundwater for domestic users,” said Nathan Draper, who oversees the irrigation district.

The project would need to be part of the Yakima Basin Integrated Plan to qualify for county, state and federal funds, he said.

YBIP is a multi-agency project that aims to assure enough water in the basin for fish, farmers and rural development.

The 7,400-acre irrigation district has been working with water marketer Aspect Consulting on the private water bank and the proposed pipeline.

Years ago the Black Rock area was the proposed site for a massive reservoir, but that project was deemed unfeasible.

Unlike most areas in the Yakima Basin, farmers east of Moxee rely on groundwater rather than surface water for agricultural operations. They’ve long pulled water from the ground for hops, fruit orchards, vegetables and dairy cows.

Many landowners are also pulling water for rural residential use and the aquifers are showing signs of depletion, said Aspect Consulting’s Dan Haller, who is in charge of the water science work on the projects.

“Everybody has been mining groundwater and it can’t remain that way forever,” he said.

Diverting water from the Yakima River to farmers east of Moxee would reduce the toll on the aquifers below and allow the irrigation district to deliver water well beyond its present service area, Haller said.

Water tables have consistently declined in all the aquifers in the area — the Upper and Lower Saddle Mountain, the Wanapum and the Grand Ronde, according to the study.

Years ago a federal study found that groundwater was linked to surface water in the Yakima Basin, where water long has been overallocated. The study suggests groundwater consumption impacts surface water supply.

Large underground basalt walls isolate the aquifers beneath the Black Rock area from the surface flow with little recharge, Haller said.

Water diverted from the Yakima River to farmers east of Moxee would have to be done in a way that doesn’t infringe on other water rights.

That could be done through water storage or by acquiring water rights from lands that have been removed from agriculture, Haller said.

Existing canals and pumps in the irrigation district would be used to move water through the pipe, he said.

The pipeline would be considered a public project — as opposed to the private water bank — and would rely on funding from farmers as well as state and federal grants.

So far, a handful of farmers each contributed $5,000 to go toward the project’s study, Haller said.

So far, the project has raised about $490,000 in grants and farmer support, he said.

Just how far east the pipeline would reach depends on the number of farmers participating.

Farmers would be assessed water fee based on acreage. But they would no longer have the pumping costs associated with pulling water from wells, some as deep as 1,000 feet, Haller said.

There’s only so much water in the aquifers and only so much time to mitigate their rate of decline before there is no water left, he said.

“We need to let folks know that there is a finite timeclock that they are living under,” Haller said.