For the second year in a row, massive flooding shut down Interstate 5 and forced evacuations in Western Washington.
What is going on here? And how can we protect ourselves from floods, which seem to be becoming more frequent and intense?
Floods are a natural part of a healthy river ecosystem. But scientists say that severe floods will happen more often in the Puget Sound area as global warming worsens – and as the impact of a changing climate is compounded by unsustainable logging practices, the paving over of wetlands and construction in floodplains.
It’s encouraging that state legislators like Sen. Phil Rockefeller, D-Bainbridge Island, are starting to discuss how we can prepare for the effects of global warming, such as increased flooding, in a way that promotes community safety and environmental health.
Government leaders on the local, state, and federal levels should follow that lead and develop science-based policies to make our human and natural communities more resilient in the face of global warming and population growth.
In the past, many cities and towns reacted to floods by building levees and floodwalls, and channeling rivers into concrete straitjackets – an approach that actually increases flood damage downstream. We now know that the best way to reduce flood damage, and to safeguard people and property, is by reconnecting rivers with their floodplains and by protecting and restoring wetlands.
Abundant, healthy wetlands should be the first line of defense against floods. They act like natural sponges, soaking up floodwaters and releasing them gradually after storms pass. A single wetland acre, saturated to a depth of one foot, retains 330,000 gallons of water – enough to flood 13 average-sized homes thigh-deep. Wetlands that are drained, filled or isolated behind levees provide little or no flood protection for the surrounding community.
Healthy wetlands that are connected to rivers and streams are good for salmon and the overall health of Puget Sound. These marshy areas provide important nurseries for imperiled salmon and steelhead. Wetland protection and restoration is an important step in restoring salmon to numbers healthy enough to support fishing and serve as an important food source for resident orcas. Wetlands also act as natural filtration systems, providing clean water to our communities.
In addition to safeguarding wetlands, we should protect trees and limit clear-cutting, especially on steep slopes, which are particularly vulnerable to erosion and landslides. We should direct new development outside floodplains, with an eye toward decreasing impervious surfaces, like pavement, which can quickly overwhelm streams and exacerbate flooding during periods of heavy rainfall.
And, we need to make sure that federal regulations protect our communities and the health of our rivers. For example, the National Marine Fisheries Service found late last year that the Federal Emergency Management Authority’s National Flood Insurance Program has enabled floodplains to be affected in ways that don’t protect people or the environment. Activities like levee construction and placing fill in floodplains have increased flood intensity, harmed water quality, and destroyed critical salmon habitat.
Levees and other structural solutions will continue to be part of the flood control strategy in some communities to protect existing development within floodplains, but the real answer to long-term safety and well-being lies in working with nature, not against it.
In some places, where no reasonable amount of wetland protection, restoration or engineering can protect a neighborhood or business from chronic flooding, the safest and most cost-effective approach to sparing life and property is to relocate buildings to higher ground.
The benefits that healthy wetlands and rivers offer to communities in terms of flood protection, clean water, wildlife and recreation are clear. Our elected officials at the local, state and federal levels should place new emphasis on the restoration of natural flood protection as the most cost-effective way of safeguarding lives and property, as well as ensuring the health of our rivers and the fish and wildlife that depend on them.
Michael Garrity of Tacoma is Washington conservation director of American Rivers, an advocacy organization that promotes healthy rivers.
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