A new study conducted by Oregon State University economists and a U.S. Geological Survey hydrologist has found that groundwater use in Oregon’s Harney Basin exceeded sustainable rates 20 years before its impacts were widely recognized.
The analysis reveals that managing groundwater is challenging due to its hidden nature and lack of comprehensive regulation.
As a result, over-extraction has led to declines in groundwater levels, affecting both agricultural irrigation and residential water supplies, as well as environmental flows crucial to areas like the Malheur National Wildlife Refuge.
The study highlights that, despite various proposed solutions, none would sufficiently stabilize groundwater levels without drastic changes. For example, even the adoption of water-efficient irrigation technologies would only reduce water pumping by 5%.
To reverse the declines and maintain environmental and residential water supplies, the study suggests reducing groundwater pumping by nearly half, which could result in a $7.5 million to $9 million annual loss in farm profits.
The researchers developed a hydro-economic model combining geologic, climate, and agricultural data to simulate the impacts of different scenarios over the next 30 years.
The status quo trajectory showed continuing declines in groundwater levels, with up to 65 feet of decline in some areas, leading to a 19% drop in environmental flows and 65 more wells going dry. Solutions like limiting water use or reducing pumping in specific areas would still lead to significant reductions in farm profits.
The study emphasizes that Oregon’s water laws currently lack the flexibility seen in other resource management systems, such as ocean fisheries, where managers can adjust allowable catch levels annually to ensure long-term sustainability.
Groundwater managers in Oregon do not have similar tools, which makes effective and adaptive management more difficult.
The study’s findings are aimed at helping not only Harney Basin but also other regions facing similar groundwater management challenges.