Lower Snake River Dams Transportation Study
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On this page: How to use this site | Study overview | Study area | Scenarios overview | Total Logistics Cost (TLC) model status | Future mitigation scenarios | Next steps | How to stay involved | Tell us how we did! | Additional feedback
How to use this site
This online open house provides information about the Lower Snake River Dams Transportation Study and describes future mitigation scenarios to show how transportation and infrastructure might change if the Lower Snake River dams are removed. The mitigation scenarios have been developed based on technical analysis and stakeholder feedback.
The site is organized into three main sections that allow you to:
- Review the benchmark and future mitigation scenarios
- Learn about the modeling process
- Provide feedback on the proposed mitigation scenarios
The information presented in this online open house is being shared to keep the community informed of the study progress and to provide an opportunity for input on the future mitigation scenarios that the study team will consider as they refine the scenarios. The study team will take your feedback into consideration as they continue working with the scenarios. Please be as specific as possible with your comments, focusing on the study and the mitigation scenarios.
Note that comments in favor of or in opposition to removing the dams or impacts on salmon are outside the scope of this study.
Your answers will be anonymous. This online open house will be open from January 26-February 9, 2026.
Study overview
WSDOT is conducting an analysis of the road, rail, and barge systems in the Lower Snake River region to understand the impacts on transportation if four dams along the river are removed: Ice Harbor, Lower Monumental, Little Goose and Lower Granite. Recent studies by the U.S. Army Corps of Engineers, Bureau of Reclamation, and Bonneville Power Administration (July 2020) and another by National Oceanographic and Atmospheric Administration (NOAA) National Marine Fisheries Service (September 2022), have explored in detail the benefits and drawbacks of removing the Lower Snake River dams for the benefit of native fish species. However, there has been limited focus and understanding of how transportation would be affected. To this end, the Washington State Legislature asked WSDOT to conduct an analysis of the effects of shifting the movement of freight and goods that currently move by barge to instead be transported by truck and rail.
Currently, large quantities of freight and goods move by barge through the Lower Snake River dams. Several industries, especially the agricultural sector, have relied on barge transportation for decades. If the dams are removed, barges would no longer operate on this section of the river, and those goods would need to shift to truck, train, and/or via the Columbia River. This study looks at what infrastructure changes and improvements would be needed to accommodate this shift, and assesses the impacts on safety, air quality, greenhouse gas emissions, and physical infrastructure.
Study area
Image caption: The Snake River originates in Wyoming and travels across southern Idaho, then north along the Idaho-Oregon border where it enters Washington and flows west to the Columbia River. The study area is focused on the region surrounding the Lower Snake River in the southeast Washington counties of Whitman, Asotin, Garfield, Columbia, Walla Walla, Benton, and Franklin.
In the 1960s and early 1970s, the federal government built four large locks and dams on the Lower Snake River: Ice Harbor, Lower Monumental, Little Goose, and Lower Granite. The U.S. Army Corps of Engineers owns and operates the four dams along the Lower Snake River. These dams are multiple-use facilities that provide navigation for barge traffic, hydropower used as part of local energy transmission, recreation, and fish and wildlife conservation benefits. These locks and dams allow for barge transportation by raising and lowering barges between different pools along the river.
Scenarios overview
If the dams on the Lower Snake River are removed, barge traffic will be shifted to road, rail, and downstream ports on the Columbia River. The study team developed a Total Logistics Cost (TLC) diversion model to estimate the changes in train, truck, and barge traffic (to transport grain, fertilizer, and wood) and to develop alternative infrastructure if the dams are removed. Using the model, the study team has identified and evaluated seven scenarios to describe current and future transportation conditions if the Lower Snake River dams remain in place or are removed. These scenarios are summarized directly below and detailed in the subsequent sections.
Benchmark scenarios | Future Mitigation scenarios |
These scenarios show how transportation would function with and without the dams. These scenarios do not include any changes to rail or road infrastructure.
| If the dams are removed, goods currently moved by barge would need to shift to rail or truck. These scenarios present changes to rail or road infrastructure that would be needed to mitigate impacts of truck and train traffic. These scenarios are in progress as of December 2025. To date, three future mitigation scenarios have been developed:
Click here to learn more about Future Mitigation Scenarios 5 - 7 >> |
Total Logistics Cost (TLC) model status
The model results for the future mitigation scenarios below is current as of December 2025 and is a work in progress. The study team is continuing to update the models and refine the scenarios based on technical analysis and community input. The Next Steps section below includes an overview of the study timeline.
The information presented in this online open house is being shared to keep the community informed of the study progress and to provide an opportunity for input on the future mitigation scenarios that the study team will consider as they refine the scenarios.
Future mitigation scenarios
This online open house shows the status of the current TLC model and how it estimates changes to transportation of goods if the dams are removed - This is covered in the following four sections:
- Annual grain tonnage flows
- Annual barge volumes
- Annual train volumes
- Peak daily trucks
Each section describes the model results for the three future mitigation scenarios (Scenarios 5-7) in terms of how they move product through the transportation network. You can leave a comment in any section where you have feedback on the proposed mitigation scenarios.
Note that barge, train, and truck volumes include both loaded and empty vehicles for all scenarios. All future scenarios are a 2045 analysis year and compare themselves to Scenario 3 (conditions in 2045 with the dams in place).
The study team is continuing to make model improvements to some of the scenarios, including refining the rail terminal capacity, and correcting the representation of rail infrastructure near Pullman and Walla Walla.
Provide input to the future mitigation scenarios in each section below
Annual grain tonnage flows
The future mitigation scenarios in this section show what might happen to annual grain tonnage flows for barge, rail, and truck transport compared to Scenario 3 (2045 with dams in place). In these scenarios, the Lower Snake River dams are removed and barge traffic is eliminated on the Snake River from Ice Harbor dam to Lewiston, Idaho, however barge operations are maintained on the Columbia River.
Scenarios 5, 6, and 7 show how goods might change and what infrastructure improvements might be needed in the future (2045) if the dams were removed.
Click the green button on the right to learn more about and provide feedback on the future mitigation scenarios for this metric.
Annual barge volumes
The future mitigation scenarios in this section show how barge volumes on the Columbia River might change compared to Scenario 3 (2045 with dams in place). In these scenarios, the Lower Snake River dams are removed and barge traffic is eliminated on the Snake River from Ice Harbor dam to Lewiston, Idaho. Barge operations are maintained on the Columbia River.
Click the green button on the right to learn more about and provide feedback on the future mitigation scenarios for this metric.
Annual train volumes
The results in this section show how train traffic might change under each mitigation scenario compared to Scenario 3 (2045 with dams in place). Each scenario shows different levels of train traffic and depending on the type and the location of rail infrastructure improvements. Some scenarios use large unit train terminals that carry goods directly to export markets, while others use shortline rails.
Click the green button on the right to learn more about and provide feedback on the future mitigation scenarios for this metric.
Peak daily trucks
The scenarios in this section show how truck traffic might change under each mitigation scenario compared to Scenario 3 (2045 with dams in place). Peak daily trucks refers to the number of trucks that are traveling in the study area during an average day in the harvest season, which is the time period of peak traffic conditions. Without barges on the Lower Snake River, freight must travel to rail terminals or to barge ports on the Columbia River. Each scenario shows different levels of truck traffic based on the location of the loading facilities.
Click the green button on the right to learn more about and provide feedback on the future mitigation scenarios for this metric.
Next steps
The study team is continuing to make model improvements to some of the scenarios, including refining the rail terminal capacity and fixing the rail infrastructure near Pullman and Walla Walla. In addition to their work addressing the model updates, the study team will take feedback from the online open house into account to develop a new Scenario 8 and move into Phase 3 of the study.
During phases 3-4, the study team will continue to gather feedback through various engagement activities with agency partners, Tribes, key interested parties, and community members. The final mitigation scenarios will be shared with the community this summer and the final report will be submitted to the State Legislature at the end of this year.
Upcoming engagement will include:
- Coordinating with industry partners
- Continuing the technical and community advisory committees
- Hosting a final set of in-person open houses
- Providing briefings to groups and organizations within the study area
- Sharing study updates through WSDOT’s GovDelivery online email service and study website
How to stay involved
There are several ways you can stay involved in the study:
- Our study website provides links to reports and resources: wsdot.wa.gov/construction-planning/search-studies/lower-snake-river-dams-transportation-study
- Sign up for study updates via WSDOT GovDelivery
- Questions? Contact:
Tell us how we did!
We are looking for feedback on the effectiveness of our outreach. We want to make sure we are reaching the community affected by this study, providing valuable information and meaningful opportunities for engagement. Please take a few minutes to fill out this survey and tell us how we did!
Survey link: https://bit.ly/LSRD-public-engagement-survey-2026
Additional feedback
Please let us know if you have additional questions below.
Do you have additional feedback about the study, model, or future mitigation scenarios?
Write your question below and we will get back to you as soon as possible.
Note that questions or comments in favor of or in opposition to removing the dams or impacts on salmon are outside the scope of this study.
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