Lower White River Countyline Levee Setback Project

Current Conditions

In October 2017, after a heavy rainstorm and with flows reaching 2000 cubic feet per second (CFS), the White River flows rejoined into its former floodplain at the Countyline project site. The overtopping occurred exactly where the Countyline project designers expected it to. The floodplain floodwaters are confined by a new levee that is set back from the river channel. Portions of the historical floodplain are now inundated, again, in keeping with project design.

Below is a flyover video taken on Oct. 23, 2017, showing the White River overtopping the excavated area of the old levee and flowing into the project area.

Overview

Significant flooding in January 2009 affected more than 100 residences and numerous businesses in the City of Pacific and temporarily closed Stewart Road E due to overtopping by floodwaters east of the 8th Street Bridge. This flooding was due in part to the ongoing sedimentation in the White River; because of its gradient change, the White River near Pacific has been gradually losing channel capacity over the last several years. The goal of the Countyline Levee Setback Project is to address this loss in channel capacity and reduce flood elevations in the City of Pacific by removing 4,500 linear feet of existing levee and reconnecting the river with 121 acres of off-channel aquatic habitat. The river has been isolated from its historical floodplain at Countyline for nearly a century. A new setback levee, 6,000 feet in length, has been built. The new levee is protected by a 5,780-foot wood structure called a bio-revetment and several engineered log jams. By giving the White River more room, the Countyline Levee Setback Project provides significant flood risk reduction benefits for more than 200 residential properties.

Project Status

The project was completed in the fall of 2017. It was built over two construction seasons (2016 and 2017). Staff are now monitoring the project to ensure the project is performing as designed. Construction during the summer of 2016 included clearing portions of the project area, grading the site and installing engineered log structures. During the 2017 season, a new setback levee was built, the bio-revetment was put in place, and the old levee was excavated in several locations so as to allow the water to overtop and flow into the off-channel during high-flow conditions.

Videos

Below is a video that was made in August 2017, during the second -- and final -- year of construction.

Other videos about the project:

• A time-lapse video that shows the 2016 construction process
• A flyover video right after the 2016 construction season
• A video from a media event at the site on Oct. 3, 2017, announcing the project's completion.
• A short video that shows the first breach of the excavated levee on Oct. 22, 2017

Project area

The Countyline reach of the Lower White River is bounded by the A Street and Burlington Northern-Santa Fe (BNSF) Railway bridges at the upstream end (River Mile 6.33 ) and the 8th Street Bridge at the downstream end (RM 5.00). The Countyline reach spans the King-Pierce County boundary.

Project elements

• Acquire all at-risk and necessary properties required to construct the project.
• Construct 6,000 lineal feet of new setback levee along the landward edge of a forested buffer to protect existing properties and structures.
• Construct 5,780 lineal feet of bio-engineered bank revetment along the existing wetland edge to protect existing properties and structures.
• Install engineered log structures in the existing wetland complex.
• Remove approximately 4,500 lineal feet of levee and bank armoring.
• Restore a forested riparian buffer (approximately 18 acres) adjacent to the wetland. 

Project costs and sponsors

The total project cost is estimated to be $24 million.

• $17.9 million - King County Flood Control District
• $823,000 - State Salmon Recovery Funding Board grant
• $500,000 - Pierce County funding
• $4.8 million - Natural Resource Damage Assessment participants

The King County River and Floodplain Management Section is overseeing the design and construction of this project, which is being implemented on behalf of the King County Flood Control District (external link).

Click the below image to enlarge the project's draft conceptual design.

Project milestones: Updated November 2017

Supporting documents

The project documents are available in Acrobat format.

SEPA documents

• Determination of Non-Significance, Oct. 2012 (118 KB)
• SEPA Checklist, Oct. 2012 (223 KB)
• Decision to proceed, July 2013 (68 KB)

Project design documents

• Final design drawings, March 2016 (27 MB)
  
• Basis of Design Full Report, Feb. 2014 (98 MB) Or as individual documents below
• Basis of Design Report (33 MB) Main report without appendices.
  • Appendix A – ELJ Concept Design Report, June 2011 (5.9 MB)
  • Appendix B – Geomorphic Assessment, Dec. 2013 (3.6 MB)
  • Appendix C – 8th Street E Bridge Scour Analysis, Aug. 2013 (0.3 MB)
  • Appendix D – Hydraulic and Sediment Transport Modeling, May 2012 (5.5 MB)
  • Appendix E – Final Hydraulic Modeling Results, Dec. 2012 (28 MB)
  • Appendix F – Floodplain Geomorphic Surface Development Approach, May 2012 (0.7 MB)
  • Appendix G – Hydraulic Modeling Approach – Initial Results, Oct. 2012 (5.6 MB)
  • Appendix H – Geotechnical Analysis, Sept. 2013 (10.6 MB)
  • Appendix I – ELS Design and Analysis, Feb. 2014 (16 MB)
  • Appendix J – Countyline 60 Percent Design Drawings, May 2013 (17.6 MB)
• Countyline Wood Recruitment Study, Aug. 2011 (5.2 MB)
• Countyline Large Wood Safety Checklist, March 2011 (0.6 MB)
• Countyline Design (30 percent) Alternatives Analysis, Oct. 2012 (15.4 MB)
• Public Safety Management Plan Countyline Levee Setback Project, Jan. 2017 (5.8 MB)

Monitoring Reports

• Countyline Levee Setback Project Year 3 Monitoring Report, Jan. 2022 (8.22 MB)
• Countyline Levee Setback Project Baseline Monitoring Report, Nov. 2020 (3.30 MB)
• Countyline Levee Setback Project Year 1 and 2 Monitoring Report, Nov. 2020 (7.78 MB)

Other information and external links

• White River Countyline Levee Setback Project Habitat Monitoring Plan - 2014 (13.8 MB)
• USGS Channel Capacity and Sediment Transport Report, 2010 (14.7 MB)
• USGS Geomorphic Analysis of the River Response to Sedimentation Downstream of Mount Rainier, Washington, 2012 (10.3 MB)
• Summary of Sediment Trends – Lower White River, 2010 (10.7 MB)
• Wetland Delineation Report, 2013 (3.8 MB)
• Lower White River 2009 to 2016 In-Channel Sediment Monitoring, 2017 (6.39 MB)       
• King County Flood Control District (external link)
• Pierce County’s Lead Entity home page for WRIA 10/12 (external link)
• Pierce County Levee Setback Feasibility Study (external link)
• Salmon Habitat Limiting Factors for the Puyallup River Basin (WRIA 10)
• WRIA 10/12 Salmon Habitat Protection and Restoration Strategy (pdf, external link)
• Pierce County Flood Control Zone District (external link)

For more information about the White River, contact Jeanne Stypula, White River Basin Supervisor, King County River and Floodplain Management Section.