Replacing Stream Diversions with Wells

The Cascadia Conservation District (CCD) and Trout Unlimited (TU) are working together to decrease instream structures that divert water from the Entiat River and Roaring Creek in Central Washington. These streams provide valuable salmon habitat and the direct diversions reduce streamflow in the lower Entiat basin during the irrigation season to a dangerous level for steelhead rearing and spawning.

In an effort to substitute groundwater sources for direct surface water diversions, and thereby reduce impacts on salmon habitat and streamflow, CCD and TU submitted 15 water right change applications to the Washington State Department of Ecology as part of the State’s Cost Reimbursement Program. The biological benefits to this change are numerous and important to the long term management goals for the Entiat River basin, as laid out in the Entiat (WRIA 46) Watershed Plan. CCD, as part of their Offstream Water Well Implementation project, or “surface water to wells,” proposed to replace a diversion on the Entiat River. TU targeted diversions of Roaring Creek, the only perennially accessible stream supporting steelhead rearing and spawning in the lower Entiat basin. These efforts address the major biological limiting factors of low flow, temperature and fish passage.

Approach

GeoEngineers coordinated the water rights applications processing with the CCD and TU, which are funding construction and equipping new shallow irrigation wells for the thriving fruit-growing community in the Entiat River basin.

In total, GeoEngineers helped Ecology process 15 applications. Our services included:

• Reviewing historic maps and aerial photographs, water right files, and court documents related to a complex adjudication in 1919.
• Examining numerous technical references related to the geology and hydrogeology of basin.
• Conducting a site visit confirming the surface water diversions and groundwater sources.
• Evaluating the four-part test that is conducted for each water right application: 1) the water must be available, both physically and legally; 2) there must be no impairment of existing senior water rights; 3) the water must be put to beneficial use; and 4) the water use must not be detrimental to the public interest.
• Completing 15 Reports of Examination for Ecology that served as official documentation of the water rights analysis.

The main challenge in this project was developing a clear understanding of the complex court adjudication documents and the history of irrigation water usage for each application. Some rights had overlapping places of use, intricate ownership histories, and complex irrigation share allocations. Another challenge was coordinating the processing with 12 different water-right holders for two different projects, each with unique goals and considerations.

Results

In general, removing stream diversions and instream structures from a river has a positive impact on aquatic habitat. Diversions and instream pumps require frequent servicing that involves entering the river to repair structures, removing silt and debris from screens and maintaining pushup dams. Replacing a stream diversion with a well alleviates the need for repeat construction in the river and the associated disturbances from increased silt loading and streambank modifications. The added benefit to the farmers is sand-free water from a groundwater source, which reduces the frequency of clogged filters and sprinkler heads.

Initially, the water right analysis project was for seven change applications on the Entiat River. However, based on our efforts there, Ecology contracted GeoEngineers to process the eight applications on Roaring Creek. GeoEngineers successfully produced 15 concise Reports of Examinations that met the State’s water right process and the applicant’s needs.