US Army Corps of Engineers
Seattle District


Chief of Engineers' response

The Final Independent External Peer Review Report (Final IEPR) is now available for download below. The Chief of Engineers' response to the independent panel's peer review report is currently under development, and will be posted and distributed within 10 days of completion and signature. 

Puyallup River Basin Flood Risk Management Study


The Puyallup River Basin Flood Risk Management General Investigation is a single-purpose flood risk management feasibility study to address flood risks in the Puyallup River Basin in Washington. The non-Federal sponsor for this study is Pierce County, Washington.  

The intent of Federal action is to reduce flood risks, life safety threats and damages in the Puyallup River Basin as a result of flooding. The action is needed because the basin experiences frequent flooding, resulting in damages to both rural and urban areas throughout the basin.  

The purpose of the Puyallup River Flood Risk Management General Investigation Study is to identify, evaluate and recommend an appropriate, coordinated, implementable solution to the identified flood risk problems and opportunities in the basin.

About the Puyallup River Basin    

The Basin drains approximately 1,000 square miles of western-central Washington and originates on the glaciers of Mount Rainier in the Cascade mountain range and flows in a northwesterly direction to Commencement Bay on Puget Sound.  

The Basin is diverse and comprised of three glacially-fed rivers, the Puyallup River and its tributaries, the White River and the Carbon River. Each of these major river systems originates on the northern slopes of Mount Rainier and join together upstream of Tacoma before draining into Puget Sound.  

In addition to two Federal authorized levees, the Basin contains a patchwork of locally constructed and maintained levee systems on each of the tributaries and the mainstem river. Most of the non-Federal levees were constructed during a period between the 1910s and the 1930s and many have been repaired, realigned or otherwise modified in the ensuing decades. The existing levee systems have experienced significant and repetitive damages increasing overall flood risks. Portions of the basin are subject to channel constrictions caused by levees, revetments and bridges, which limit channel capacity, thereby increasing flood risks.  

About the Tentatively Selected Plan (TSP)  

Using a risk-informed decision-making process and following the U.S. Army Corps of Engineers’ (Corps) six-step planning process, the Corps has identified the Levee Modification Alternative as the TSP. This alternative would modify the existing levee system to manage flood risk by setting back an existing levee, increasing existing levee heights, improving existing levee reliability, or constructing new levees or floodwalls. The proposed levee modifications would be the primary flood risk management measure within this alternative and would work with other flood risk management measures in the alternative to reduce flood risk in the basin. This is a passive approach to managing sediment, where levees are modified in order to accommodate the sediment deposition expected over the planning period of analysis.  

The TSP includes approximately 11.2 total miles of new levee and/or floodwall construction and approximately 8.7 total miles of modification to existing features, including a levee setback. Actual levee alignments and alternative measures will be refined during feasibility-level design analysis.  Details of the plan formulation process and the TSP are included in an integrated Draft Feasibility Report / Environmental Impact Statement (DFR/EIS). The DFR/EIS documents the planning process for flood risk management in the Puyallup River Basin, to demonstrate consistency with Corps planning policy and to meet the regulations that implement the National Environmental Policy Act (NEPA).

Officials from the Corps and Pierce County, Washington accepted public comments on the DFR/EIS during a 45-day public comment period, March 25 to May 23, 2016. The DFR/EIS is available for viewing online via document links on the left.  A paper copy was available at the Puyallup Public Library and Pierce County Library branch in Orting for the public comment period. Check with the libraries on availability.

The Corps hosted a public meeting to provide project updates and accept public comments on the DFR/EIS and the Tentatively Selected Plan April 19, 2016 at the Puyallup Activity Center.

Public comments received during the public comment period and at the public meeting will be considered as the Corps and Pierce County work toward completing a basin-wide flood risk management plan.

For more information contact:

Mail: Scott Long

U.S. Army Corps of Engineers


P.O. Box 3755

Seattle, WA, 98134-3755

Phone: (206) 764-6697