Environmental

Willamette Valley operations could be impacted by Corps changes

Engineers and planners with the U.S. Army Corps of Engineers are considering changes that may impact ongoing operations and maintenance (O&M) activities of the Willamette Valley System (WVS) in Oregon.

The Corps’ Portland District operates 13 dams in the Willamette River basin. Each contributes to a water resource management system that provides flood risk management, power generation, water quality improvement, irrigation, fish and wildlife habitat and recreation for the river and its tributaries. Nine of the Willamette Valley dams generate hydroelectricity, with a total capacity of 500 MW. Eight of these facilities are owned and operated by the Corps and one is a private facility licensed by the Federal Energy Regulatory Commission.

Corps staff continue developing an Environmental Impact Statement (EIS) for WVS O&M in accordance with authorized project purposes, while meeting Endangered Species Act (ESA) obligations to avoid jeopardizing the continued existence of listed species.

As part of the EIS development, the Corps is hosting a virtual information session on Jan. 19 to review its progress. The meeting will provide summarize the process the Corps has gone through to identify alternative ways of operating and maintaining the WVS, while meeting ESA requirements. The Corps said the information session and virtual room are not a forum for public comment. It said it will seek public comment on the draft EIS in the fall.

The WVS EIS is reshaping future operations in the Willamette Valley and the Corps is analyzing a broad range of alternatives, including:

  • High-value structural options such as floating fish facilities and temperature control towers
  • Operations, which may be impactful for some authorized purposes. This can include water release through diversion tunnel, regulating outlets, delayed refills or spillways, which could affect recreation, water supply and water temperature (quality).
  • A combination of the structures and operations

Through the WVS operations & maintenance EIS, the Corps will disclose the environmental impacts of its continued O&M of 13 multipurpose dams and federal oversight of 43 miles of revetments in the Willamette River Basin. It will further disclose the environmental impacts of implementation of various operations, construction and related activities, including for downstream fish passage and temperature control at various projects.

These alternate approaches to balancing authorized purposes will not affect flood risk management but will have important tradeoffs for stakeholders and decision makers to consider.