Puget Sound’s major rivers and their floodplains deliver a wealth of economic, natural and cultural benefits and make the region a place we all love to call home. Yet floodplain management has not kept pace with our growing communities- people are living in the path of flood waters; our water quality is on the decline; and habitat critical to restoring salmon populations is disappearing. The Floodplains by Design partnership is bringing funding to implement projects that achieve multiple objectives – they improve flood protection, restore salmon habitats, improve water quality, improve agricultural vitality and enhance outdoor recreation.
Puget Sound’s lowland river valleys are among the region’s most valuable assets, delivering a wealth of economic, natural and social benefits. These floodplain areas contain the region’s richest farmland, and host the Sound’s signature salmon runs. They feature commercial, residential, and industrial development valued at over $18 billion. They support wetlands and forests that filter pollutants out of our water sources. They recharge aquifers and provide recreational opportunities for the 4 million people who live in the Puget Sound region. However, Puget Sound communities are at increasing risk from rising sea levels, more extreme coastal storms, and more frequent river flooding.
Despite the many values they contain, Puget Sound floodplains are also home to the most damaging natural disasters in the state: floods. Over 1000 critical public facilities, including hospitals, schools, and fire stations are located within Puget Sound’s floodplain areas.
Population growth and development continues to change the landscape, increasing the number of people in harm’s way and compromising river functions. The agricultural industry is trying to maintain its viability in the face of increasing development, habitat restoration and regulatory pressure. Further, flood response and repair costs are increasing while federal funds for
flood control facilities are decreasing, and investments in habitat or water quality improvements are overwhelmed by investments in activities that degrade river functions.
Habitats and Species
Meanwhile, salmon runs continue to decline, despite the recognition that the protection and restoration of floodplain ecosystems is a critical component of salmon recovery in Puget Sound. With the region’s population growing rapidly and climate change forecasts calling for more frequent and severe winter flooding, the problems continue to grow.
In 2013, the State of Washington invested $33 million in nine projects that are using the Floodplains by Design integrated approach to enhance floodplain management in the Puget Sound watershed. These projects leverage an additional $80 million in other state and federal funds. A comprehensive framework is being developed for the highly developed Green River; the Skagit River Fish Farm and Flood Initiative is identifying ways to reduce flood risk while planning for salmon recovery and preserving farmland. Similar efforts are underway on the Cedar, Dungeness, Pysht, Skokomish, Snohomish, Snoqualmie, Stillaguamish and Tolt rivers. What we do over the next 10 years will define the quality of life for Puget Sound’s communities. It will influence the health of the region’s agricultural industry, the cleanliness of its waters, and the vitality of its salmon runs.
The main goal in Puget Sound is to improve the resiliency of these floodplains for the protection of human communities and the health of the ecosystem, while supporting values important in the region such as agriculture, clean water, a vibrant economy and recreation.
The Calistoga Reach Setback Levee and Side-Channel Construction project near the City of Orting, WA involved moving people out of harms’ way and removing existing levees and a road. By installing a setback levee, this project restored natural functions to approximately 280 acres that were previously the site of repeated flood damages, creating economic burdens and putting citizens and responders at risk.
Reconnecting rivers to their floodplains helps restore habitat for native species including ESA-listed Chinook and steelhead trout, and reduces flood risks to public infrastructure and private farms. The Snoqualmie River Fall City Corridor project will restore up to 105 acres of degraded floodplain. Ultimately, this solution will improve habitat, protect farmland and reduce flooding by reconnecting the river to 250 acres of floodplain area in this reach.
Sometimes nature-based solutions can work together with built infrastructure to provide the biggest benefit. The Port Susan Bay Estuary Restoration Project restored 150 acres of tidal marsh in the Stillaguamish River estuary. An outer dike was removed and an inner dike redesigned to provide greater protection for neighboring farmlands during floods, and improve the ability of fish caught in flood waters to return to the natural system.
Now, native tidal-wetlands that support estuary-dependent animals are in better condition, juvenile chinook salmon have access to restored rearing habitats, and the stronger connection between the river and tidal habitats will improve the resilience of the estuary and dike infrastructure to sea level rise. Healthier tidal wetlands also mean more food in the system for salmon, Dungeness crab, gray whales . . . and people.
The Floodplains by Design partnership is led by The Nature Conservancy, Puget Sound Partnership, and the Department of Ecology. Participating partners on the Floodplains by Design partnership also include the Federal Emergency Management Agency, King County, Kramer Consulting, Carol MacIlroy Consulting, Master Builders Association of King and Snohomish Counties, National Oceanic and Atmospheric Administration, Normandeau Associates, Pierce County, Skokomish Tribe, Snohomish County, Snohomish County Sustainable Lands Strategy, Tulalip Tribe, United States Army Corps of Engineers, United States Environmental Protection Agency, United States Geological Survey, Washington Military Department Emergency Management Division, Washington State Dairy Federation, Washington State Department of Fish and Wildlife, and the Washington State Department of Transportation.
For the latest reports, publications, and information on Puget Sound Coastal Resilience and Floodplains by Design, please visit www.floodplainsbydesign.org