Groundwater levels in Southeast Oregon’s Harney Basin are dropping but a potential solution might hammer farmers’ wallets, according to a new study.

The analysis, from Oregon State University economists and a U.S. Geological Survey hydrologist, comes as the Oregon Water Resources Department is working with community stakeholders to develop a plan dealing with overpumping.

“One of the issues is how much reduction is going to be needed and over what time period,” said William Jaeger, an OSU professor of applied economics.

About half of the irrigation in the basin comes from groundwater, Jaeger added.

The new study also showed that sustainable rates of groundwater withdrawal in the Harney Basin were surpassed 20 years prior to the time declining groundwater levels were generally recognized.

Halving groundwater pumping rates would help halt groundwater level declines, prevent wells from drying up and stabilize environmental flows.

Doing so, however, would cut area farm profits by $7.5 million to $9 million annually, essentially half what they are today.

The profit baseline for Harney Basin groundwater irrigators, who primarily grow alfalfa, was about $18 million.

The baseline for total revenue in the study was $49.6 million and that dropped to $25.4 million in the scenario where groundwater irrigation is trimmed by roughly half the initial level.

Global groundwater decline

Groundwater levels have been declining globally, across the U.S. and in other parts of Oregon, so the study’s modeling methods and findings will provide benefits well beyond Harney County, Jaeger said.

“Groundwater is challenging to manage because it is hidden below ground and poorly understood,” Jaeger said.

“It’s frequently extracted at unsustainable rates because, without effective regulation, individual water users have an incentive to act without considering impacts on others. This can lead to negative effects on all water users and the environment,” he added.

Considering alternative scenarios

In the semi-arid and sparsely populated Harney Basin, groundwater pumpage has increased since the 1990s, resulting in declines in groundwater levels.

Researchers considered 15 alternative scenarios 30 years in the future with various actions to stabilize groundwater levels.

The baseline was calibrated from 2018 and used average years — at that point — in terms of climate and precipitation. “The true situation is likely somewhat different,” Jaeger acknowledged.

The study found several proposed solutions wouldn’t help much. Requiring more water-efficient irrigation technologies, for example, would reduce water pumped by only 5%.

All scenarios resulted in lower annual farm profits.

Under the status quo, $2 million or 10% of farm profits would be lost, 65 additional wells would go dry and environmental flows would drop 19%.

Jaeger said a surprising result was projected profit per acre decreases wouldn’t be significant enough to stop ag operators from pumping. “The problem won’t self-correct,” he said.

New management tool needed

The groundwater decline in the Harney Basin illustrates a structural problem for managing the resource in Oregon, Jaeger said.

Oregon’s water laws aren’t designed with the kind of flexibility necessary to manage a changing resource like groundwater.

He pointed to coastal fisheries, where the allowable catch can be adjusted up or down from year to year to ensure sustainability.

“We need a better tool, we need a better mechanism, to deal with that transition from abundant groundwater to scarce groundwater,” Jaeger said.

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