Conconully Safety of Dams Modification Project Environmental Assessment

Frequently Asked Questions

 

Photo credit: Bureau of Reclamation

1. What is the proposed federal action?

Conconully Dam is sound and is performing as designed. The Bureau of Reclamation’s Safety of Dams program is focused on ensuring long-term stability of dams to protect lives and property. Results of the Bureau of Reclamation’s studies and analyses show the dam and foundation have a potential to liquefy during infrequent, high-magnitude earthquakes. The Bureau of Reclamation proposes to reduce the risk of dam failure by constructing a stability berm on a foundation of deep soil mixing reinforcement columns on the downstream face of Conconully Dam. To provide improved operational functionality and compatibility with the proposed stability berm, the Bureau of Reclamation also proposes to upgrade the outlet works by extending, lining, and reinforcing water conveyance components and installing contemporary water control systems and facilities (such as, multiple state-of-the-art valves and valve house). These modifications would be performed primarily downstream (dry or stream side) of the dam, with limited activities upstream (wet or reservoir side) of the dam.

2. Why is the proposed federal action necessary?

Evaluations of the risk of seismic failure associated with liquefaction of the dam’s embankment and foundation materials began in 1990s. The geotechnical and risk analyses indicated that risks were above public protection guideline values and justified additional work to better define or understand the risks. Subsequent geotechnical evaluations, field explorations, and risk analyses have shown that the dam requires modifications to reduce the seismic risks to the dam.

The need for the proposed action is to comply with the Bureau of Reclamation's Safety of Dams’ requirements and bring static and hydrologic risks at Conconully Dam below public protection guidelines, improve control of water flows through the outlet works, and increase the reliability and longevity of the dam and water conveyance system.

3. What are the benefits of the proposed federal action?

The Conconully Safety of Dams Modification project would reduce the seismic risks of dam failure, provide water deliveries and flows for irrigators and endangered species, and maintain additional benefits for recreation and fish and wildlife habitat. Improvements and modifications to the dam would effectively reduce the safety risks it imposes for the downstream public.

4. How did the Bureau of Reclamation engage the public during the scoping period?

The Bureau of Reclamation is committed to an open and inclusive NEPA process. All substantive comments will be carefully considered in our review and decision(s) on meeting the agency’s NEPA responsibilities and other applicable laws in this process.

The public can participate in the NEPA scoping process by helping to identify EA issues and potential alternatives to the proposed action and by evaluating the analysis of the proposed action and alternatives in the preliminary EA during the public review period. All substantive comments received are considered.

The Bureau of Reclamation initiated the scoping period on Aug. 9, 2024. A news release, newspaper ad, mailed postcards to potentially affected local residents, emails to interested public and stakeholders, and flyers posted in the local community were issued to announce the public comment opportunities. The public scoping comment period ended on Sept. 8.

During the comment period, the public had the opportunity to provide input and participate in the scoping process through two in-person public meetings. The in-person meetings were a combination of an open house, presentation, and opportunities for the public to submit comments. The public had the opportunity to submit comments through a variety of methods at any time during the scoping period. Comments received during the public scoping period will be summarized in a public scoping report that will be made available to the public.

5. How will the Bureau of Reclamation engage Native American Tribes?

The Bureau of Reclamation will engage the Tribes to identify sacred sites, Indian Trust Assets, and other concerns. The Bureau of Reclamation will offer the opportunity for Government–to–Government consultation with the Confederated Tribes of the Colville Reservation. Tribal representatives will be invited to actively participate in project coordination and offer expertise and Tribal perspective. The Tribes have a long history and deep cultural ties to the area. Consultation under Section 106 of the National Historical Protection Act and close coordination under NEPA will be the primary means of engagement.

6. Who are the cooperating agencies?

The Bureau of Reclamation is the lead federal agency under NEPA for development of the EA. While there are no formal cooperating agencies on the project at this time, the Bureau of Reclamation anticipates close coordination with the U.S. Army Corps of Engineers, NOAA Fisheries, U.S. Fish and Wildlife Service, Washington State Department of Fish and Wildlife, Washington State Department of Archaeology and Historic Preservation, Washington State Department of Ecology, and Okanogan County during the NEPA process and subsequent permitting efforts.

If you have more detailed questions about the Conconully Safety of Dams Modification project EA, you may reach us by email or phone via the contact information below.

 

For more information on the Conconully Safety of Dams Modification project EA, please visit the project website or contact Jason Sutter, Bureau of Reclamation NEPA lead at bor-sha-consod@usbr.gov.

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