Topic: Built Environment | Region: Western Washington | Year: 2018

Climate Impacts and Adaptation Fact Sheets for Flood Risk Managers

  • Sonia A. Hall, SAH Ecologia LLC
  • Julie Morse, The Nature Conservancy
  • Heidi Roop, UW Climate Impacts Group
  • Crystal Raymond, UW Climate Impacts Group
  • Completed
  • The Nature Conservancy
  • Floodplains By Design
  • This work was contracted by The Nature Conservancy and is part of the Floodplains By Design program. Funding was provided by the United States Environmental Protection Agency under assistance agreement number PC-011J22301 through the Washington Department of Fish and Wildlife. The contents of this document do not necessarily reflect the views and policies of the Environmental Protection Agency or the Washington Department of Fish and Wildlife, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

We partnered with The Nature Conservancy and the Floodplains by Design initiative to produce a set of fact sheets to serve as a quick reference on climate change impacts for six Puget Sound rivers. We also produced a fact sheet highlighting a variety of flood risk adaptation actions being taken in Washington State. These seven facts sheets are intended to make climate change information accessible and relevant to resource managers, city planners, engineers and others who need to plan around changing flood risks in their work. 

Fact SheetDungeness Fact SheetNooksack Fact SheetPuyallup Fact SheetStillaguamish Fact SheetSkokomish Fact SheetSnohomish Fact Sheet

Project Background

Flooding is a major challenge for managers in Washington State, with implications for habitat, livelihoods and communities. In addition, climate change is projected to drastically alter the risk of floods in the state. Rising sea level, heavier rain events, and receding snowpack will all contribute to increasing flood risk in much of the region. Flood management policies and projects that are implemented today will have impacts for decades or more – well into the time when climate change is projected to significantly affect flood risk.

While there is widespread recognition of its importance, the available information about climate change is often quite general and not directly tailored for use in floodplain management or planning. This project takes two steps towards addressing that need. First, by producing succinct and well-researched summaries of the effects of climate change on six major watersheds in the state. And second, by showcasing possible actions that can be taken to lessen the impacts of changing flood risks.

Approach

The data presented in these facts sheets summarize mean values from multiple independent studies. Reference dates and more details for these studies are provided in the State of Knowledge: Climate Change in the Puget Sound Report.

All projections are based on the RCP 8.5 high emissions scenario except for snowpack, streamflow, and stream temperature estimates which used the A1B moderate emissions scenario.
State of Knowledge: Climate Change in the Puget Sound Report

Related resources

State of Knowledge: Climate Change in Puget Sound is a comprehensive synthesis report summarizing relevant research on the likely effects of climate change on the lands, water, and people of the Puget Sound region.

Projected Sea Level Rise for Washington State – A 2018 Assessment provides an updated set of absolute and relative sea level rise projections out to 2150 for Washington state.
State of Knowledge: Climate Change in Puget SoundProjected Sea Level Rise for Washington State – A 2018 Assessment