128th Street Comprehensive Setback Levee Feasibility Study
About the Study
Pierce County Planning and Public Works is conducting a feasibility study to reduce the flooding risk and impacts along both the right and left banks of the Puyallup River, near the 128th Street East bridge crossing.
Though levees are present along both banks of the Puyallup River, this area experiences widespread flooding due to insufficient channel capacity and existing levee protection. Setback levee features can help to reduce risk from flooding to nearby property, infrastructure, and also improve fish and wildlife habitat.
The objective of this study is to learn how levee setbacks or other flood risk reduction measures would benefit the public, residents, and natural environment.
Thank you to everyone who attended the in-person and online open houses and provided comments during the public comment period. The team is currently working on reviewing and compiling the comments. View the draft study for the 128th Street East Comprehensive Setback Levee Feasibility Study.
Throughout this study, Pierce County is committed to working with the community and nearby property owners to develop alternatives and prioritize potential future projects.
- Winter 2020: Preliminary information and data gathering and early stakeholder engagement.
- Summer 2020 to Winter 2021: Study scoping, fieldwork, and early public engagement.
- Spring to Summer 2021: Identify opportunities and problems, and interim outreach and public feedback in advance of study alternatives development. Watch the 2021 Open House presentation.
- Fall 2021 to Winter 2022: Identify and evaluate draft alternatives and prepare draft feasibility report.
- Fall 2022: Share draft study findings and gather public feedback about draft alternatives.
- Fall 2022/Winter 2023: Finalize study and share results. (We are here.)
- 2023 & Beyond: Design, property acquisition, project environmental permitting and SEPA review.
Stakeholders & Community
We are committed to engaging stakeholders early and keeping the community involved throughout this study process.
A series of open houses, mail notices, surveys and interviews and will be available to the community and to those directly impacted by this project. Based on current public health guidelines from local, state, and federal public health agencies, open houses and other outreach may take place online throughout this project. We will share the most up to date information here as it is available.
2021 Survey Results
To better understand residents and stakeholders' priorities with developing flood risk reduction measures, Pierce County recently conducted an online open house, an online survey, and a series of workshops. Thank you to those of you who responded! Your responses will make sure that we are including important information in the study and prioritizing the right problems and opportunities as the work continues.
What did we hear?
- Most people who participated in the outreach period are interested community members. Some live or own property near the study area, and a few live near or on the Puyallup River.
- The community’s most common concerns regarding the Puyallup River include environmental and habitat concerns, flooding and property concerns, and development and roadway concerns.
- Most participants agreed with the identified problems and disagreed with the identified opportunities.
- Most participants think that flood risk reduction is an important, habitat creation is less important, and feel neutral about cost as a benefit.
- Participants suggested that additional benefit categories should include impacts to local residents and farmland conservation.
What will we do with the feedback?
- This results from this survey help us learn about the community’s priorities with flooding near the 128th Street Bridge. We will use this to identify additional problems, opportunities, and benefits that will inform the alternatives development.
- We heard that you want to stay connected, so as this study progresses we will send periodic updates about progress in the field and we will continue to be available for community briefings and questions.
This study is funded through a combination of SWM funds, Flood Control District funds, and grants.
The study area is east of State Route 162, west of McCutcheon Road East, south of 112th Street East and north of 144th Street East and along both the right and left banks of the Puyallup River between river miles 15.7 and 17.5, bisected by the 128th Street East bridge crossing (and north of the City of Orting limits).
This area is divided into four quadrants: NE, NW, SE, and SW to help assess the unique existing conditions, flood risk reduction opportunities and problems in each. A proposed levee setback in one quadrant may influence flood risk reduction in all three of the others. Therefore, all the quadrants are being evaluated concurrently.
The Puyallup River is Evolving
Over time, rivers erode rocks, dirt, and other sediments and deposit them downstream. This is one of several factors that can cause rivers to change course and flow into new areas over time.
The maps below show how the Puyallup River near the 128th Street East bridge crossing has changed its course over time.
The Height Above Water Surface Map (shown to the left below) shares more information about this. For example, the purple areas on the mapping indicate locations on the floodplains that are relatively lower than other areas, and the darker the purple color the lower the floodplain surface.
The patterns that are evident in the mapping show old river meander locations and other depressions that can provide increased flood storage and more frequent seasonal habitat benefits if re-connected to the river.
Historical Channel Occupation
The Historic Channel Occupation Tract Map (shown to the right above) reflects how the dynamic Puyallup River has shifted its active channel over time. Starting in 1880, the US General Land Office did a survey to start tracking river meanders. Incorporating this with the historical aerial photos taken between 1931 and 1998, we start to see a picture of how much the Puyallup river systems has changed in the last 140 years.
This Historical Channel Occupation Tract map is produced using a compilation of active historical Puyallup River channel occupation location areas changing over time. With this ever evolving channel, it’s important to understand the changes in history so we can help protect for the future.
Puyallup River (and 128th ST E Bridge Crossing) 1931 Historical Aerial Photograph
As the river moves and changes, flooding can become more pronounced during times of heavy rainfall. This flooding can damage property and public infrastructure, impact travel and evacuation routes, and cause a loss of fish habitat. Moving existing levees back from the river’s edge and reconnecting floodplains provide increased storage for flood waters. This additional capacity helps to reduce flood risks to the public, residents and property, create more reliable access to roads, reduce flooding of structures and risk of damage to the levees, fields and farmland, and create more fish habitat and spawning areas.
From our work to date, we have analyzed existing flood conditions in the study area, identified opportunities to reduce flood risk, and are starting to develop conceptual alternatives.
The video below shows a flood event passing through the study area. This animation was generated from a hydraulic model simulation of the November 2006 flood event on the Puyallup River. The animation shows the pattern, timing, and the spatial extent of flooding for existing conditions during a major flood. The peak discharge in the Puyallup River for the simulated flood event is 40,300 cubic feet per second.
What do we expect will happen if no changes are made?
There are several existing problems along the Puyallup River in the study area. If no changes are made to the current configuration of levees along this stretch of river, we can expect to experience problems in the future. These include: