The preferred alternative

5 May 2020

The proposal to remove four dams on the Lower Snake River in the US has been rejected in the draft environmental impact statement for the Columbia River System. Agencies have been working to identify the best way to establish a more collaborative and creative approach to river operations and salmon protection.

The US Army Corps of Engineers (USACE), Bureau of Reclamation (USBR) and Bonneville Power Administration (BPA) released the Columbia River System Operations draft environmental impact statement on 28 February 2020. This draft includes the preferred alternative action for operating and maintaining 14 federal dam and reservoir projects that comprise the Columbia River System in Idaho, Montana, Oregon and Washington. The idea of removing four dams along the Lower Snake River - Ice Harbor, Lower Monumental, Little Goose Lock and Lower Granite Lake dams - was rejected. 

The three co-lead agencies say that they prepared the document “in response to the need to review and update management of the CRS, including evaluating impacts to resources in the context of new information and changed conditions in the Columbia River Basin”. Furthermore, they added that information and insights from the process have enabled the development of a comprehensive approach to CRS management that meets multiple statutory authorities and complies with all applicable laws and regulations.

Lower Granite Lake Dam

Environmental impact statement

More than 30 entities from across the region, consisting of tribes, federal agencies, and state and local governments, agreed to participate as cooperating agencies in the process which is required under the National Environmental Policy Act. 

The EIS identifies and evaluates six alternatives for operations, maintenance and configuration of the CRS. After evaluating the potential effects of these on flood risk management, water supply, hydropower generation, fish and wildlife, navigation, cultural resources, recreation and other environmental and socioeconomic resources, the co-lead agencies identified a preferred alternative that sought to achieve a reasonable balance of multiple river resource needs and co-lead agency mission requirements.

In a joint statement, USACE, USBR and BPA said that, unsurprisingly, there is a wide range of views and opinions about the best approaches to managing the Columbia River System.

“However,” they continued, “it was also apparent that people throughout the Northwest share many common values and interests. Our goal has been to develop an approach to river management that balances these multiple perspectives and can serve as a springboard to continued progress in the region on recovery and mitigation for fish and wildlife, reliable and affordable clean electricity, and economic vitality for the many communities that depend on the CRS for their livelihoods. “

“The draft EIS represents a remarkable collaborative effort to gather public input and information for a current and thorough analysis of options that meet the goals of the EIS and our future responsibilities to the region,” said Brig. Gen. D. Peter Helmlinger, Northwestern Division Commander with the US Army Corps of Engineers.

“We could not have reached this important milestone without the expertise and input of the many cooperating agencies that have participated in this process,” BPA Administrator Elliot Mainzer added. “This was truly a regional effort, and we are especially grateful to our tribal partners for providing their perspectives and expertise on the Columbia River System.”

Ice Harbor Dam

The alternatives

The last comprehensive update to the operating strategy for the Columbia River System was issued in 1995. Twenty-five years on, this new draft document contains detailed analyses of environmental, social and economic benefits and consequences to affected resources of the six considered alternatives for improved integrated operations.

Upon closer analysis it was considered that the no action alternative did not provide adequate improvements for juvenile and adult salmon, resident fish and lamprey as required by the EIS.

Multiple objective alternative 1 (MO1) was developed to meet all objectives while prioritising benefits to lamprey and ESA-listed fish species relative to the no action alternative.

MO2 was developed to prioritise hydropower production and flexibility and reduce regional GHG emissions, benefit lamprey and ESA-listed salmon through structural measures, and benefit ESA-listed salmon through increased transport. It will also meet the other study objectives and avoid or minimise adverse impacts to other resources.

MO3 was developed to evaluate the effects of breaching the four lower Snake River dams (Lower Granite, Little Goose, Lower Monumental, and Ice Harbor) along with actions for water management flexibility, limited increases in hydropower generation in certain areas of the basin at specific times, and altered water supply (small increases in volume and small change in timing).

However, the draft EIS states that MO3 would “only partially” meet EIS objectives to various levels. Additionally, breaching the dams would not allow the co-lead agencies to operate and maintain the dams for their congressionally authorised purposes of navigation, hydropower, envisioned recreational benefits, and water supply for irrigation purposes. It also has the highest adverse impacts to other resources, especially social and economic effects, but has the highest benefits for several of the ESA-listed juvenile and adult salmon and provides additional riverine type recreational opportunities. In addition it will also return access and opportunities to some of the traditional cultural resources and properties for tribal purposes.

The co-lead agencies stated in the report that: “Despite the major benefits to fish expected from MO3, this alternative was not identified as the preferred alternative due to the adverse impacts to other resources such as transportation, power reliability and affordability, and greenhouse gas emissions. The region’s understanding of the impacts, both beneficial and adverse, of the Columbia River System will improve over time just as the perspectives and values of the people living in the Columbia Basin will continue to change as well. 

“This EIS is not expected to end the regional debate on the future of the four lower Snake River dams. On the contrary, this EIS provides information and analysis to inform that future dialogue. The co-lead agencies used the analysis in MO3 to inform and improve the development of the preferred alternative that seeks to balance managing the system for all purposes while providing additional benefits for fish and other study objectives.”

MO4 was developed with a primary focus on measures to benefit ESA-listed fish, integrated with measures for water management flexibility, hydropower production, and additional water supply. This alternative includes the highest level of spill in the range considered in this EIS, dry-year augmentation of spring flow with water stored in upper basin reservoirs, and annually drawing down the lower Snake River and Columbia River reservoirs to their minimum operating pools.

Other alternatives considered but not evaluated in detail included the reintroduction of salmon above Chief Joseph and Grand Coulee Dams into the upper Columbia Basin; plus requests to integrate the ongoing Columbia River Treaty negotiations between the US and Canada into the analysis. All of these concerns or measures were considered but removed from further analysis in the EIS.

Lower Monumental dam

The preferred alternative

The Preferred alternative was developed as part of an iterative process. It is a combination of measures included in the multiple objective alternatives using information learned during modelling and evaluation. Some of the measures were modified to improve their ability to meet objectives, or refined to avoid, reduce or minimise adverse environmental, economic and social impacts.

Examples of modified measures incorporated into the preferred alternative to address adverse impacts include:

  • A mitigation measure to address the potential for access to blocked tributaries for bull trout due to operations at Libby dam.
  • Modification of the John Day Reservoir for predator disruption. Reservoir levels would be increased before Caspian tern nesting season to dissuade nesting on islands in John Day’s reservoir, and then dropped back down to the minimum operating pool range in June as is normal during the juvenile fish migration season.

The preferred alternative is described as providing flexibility to adapt to changing conditions in the Columbia River Basin, ensuring that human life and safety can be protected through flood risk management, while protecting valuable fish and wildlife resources, supplying water to farmers and cities, and ensuring adequate, affordable and reliable power. 

Throughout this process, the co-lead agencies said that they “endeavoured to identify a way to best meet the multiple purposes and objectives of the Columbia River System, and build on recent progress in establishing a more collaborative, creative approach to river operations and salmon protection”.

The draft EIS states that many of the measures in the preferred alternative are intended to improve conditions for ESA-listed fish and lamprey. Other measures are intended to provide more flexible ways for the co-lead agencies to meet water needs for fish and wildlife, flood risk management, water supply, and hydropower in the Columbia Basin. 

Indeed, although the preferred alternative would meet objectives to provide a reliable and economic power supply, hydropower generation will still decrease by 160MW assuming average water, and 300MW assuming low water, in large part due to the increased spring spill for juvenile fish passage. However, reliability is comparable to that of the no action alternative because other measures increase hydropower generation slightly in the winter, and more substantially in late august, and increase hydropower flexibility in some locations and periods. Therefore, no additional resources are needed to maintain regional reliability. 

A reduction in hydropower generation under the preferred alternative marginally meets the minimize GHG emissions objective. In addition, air quality would most likely be degraded slightly and greenhouse gas emissions in the Northwest are likely increase by an estimated 0.70%.

“I commend the team for its commitment to identifying a preferred alternative that balances the system’s authorised purposes and our resource, legal and institutional obligations,” said Reclamation Regional Director Lorri Gray. “This is a significant accomplishment, made possible by the hard work and strong partnership with organisations throughout the region and among the US Army Corps of Engineers, Bureau of Reclamation and Bonneville Power Administration.” 

A 45-day public review and comment period followed the release of the draft EIS and will contribute toward the final EIS which is expected in summer 2020. Records of decision documenting final recommended actions will be issued in September 2020.

Little Goose Lock Dam


What is the Columbia River System?

Built and put into service between 1938 and 1976, the 14 multiple purpose dams that comprise the Columbia River System are:

  • Libby
  • Hungry Horse
  • Albeni Falls
  • Grand Coulee
  • Chief Joseph
  • Dworshak
  • Lower Granite
  • Little Goose
  • Lower Monumental
  • Ice Harbor
  • McNary
  • John Day
  • The Dalles
  • Bonneville

US Congress authorised USACE and USBR to construct, operate and maintain the dams as one interconnected system to meet multiple specified purposes, including flood risk management, navigation, hydropower generation, irrigation, fish and wildlife conservation, recreation and municipal and industrial water supply. BPA is authorised to market and transmit the power generated by coordinated system operations.

The river’s navigation system is an important component of the regional economy, allowing farmers to export grain and other crops grown in interior parts of the US to overseas markets. Cruise line operators also use the river for tourism, a growing business on the Columbia and Snake rivers.

The system is a source of economical, reliable and clean power generation and provides the region with some of the least greenhouse gas intensive electricity in the country. The Columbia River and its tributaries provide water for millions of people throughout the river basin, while farmers depend on system water to irrigate crops that contribute to the national economy.

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