Restore Natural Flood Protectionsby Rob Masonis
Seattle Post-Intelligencer, January 17, 2006
Mudslides. Road washouts. That constant drip, drip, drip. After 27 consecutive days of rain in Western Washington, we are all feeling the effects. Land is saturated and local rivers such as the Green and Nisqually are rising, and still the forecast calls for more rain.
Officials have issued flood warnings for some low-lying communities. While we work as a region to ensure the safety of these communities, we also need to assess what we can do to prevent dangerous and damaging floods in the future.
Floods are a natural part of a healthy river ecosystem. In the past, many communities reacted to floods by building levees and floodwalls, channelizing rivers in concrete straitjackets. We've learned that approach actually increases flood damage downstream. We now know 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 and healthy wetlands should be the first line of defense against floods. They act like natural sponges, soaking up floodwaters and releasing them gradually after a storm has passed. 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 are good for salmon, too. These marshy areas provide important nurseries for endangered salmon, and wetland protection and restoration is an important step in recovering salmon to healthy, fishable numbers. Wetlands also act as natural filtration systems, providing clean water to our communities.
In addition to protecting wetlands, we should protect trees, especially on steep slopes, and limit clearcuts. We should also build neighborhoods and other developments with an eye toward decreasing impervious surfaces, like pavement, which can quickly overwhelm streams and exacerbate flooding during periods of heavy rainfall. Instead we should promote more natural drainage solutions that allow rain to soak into the ground, which has the added benefit of increasing water supply during the dry summer months.
Levees and other structural solutions will continue to be part of the flood control strategy in some towns to protect existing developments, but the real answer to long-term community safety and well-being lies in working with nature, not against it. Additionally, in cases where no amount of habitat protection, restoration or engineering will protect a neighborhood from chronic flooding, the safest and most cost-effective approach to sparing life and property is to relocate buildings to higher ground.
The recent rains and flood warnings should drive home the importance of strong land-use protections, such as Critical Areas Ordinances that are being updated by many Washington counties. To decrease the risk of flood damage, these ordinances should steer development away from wetlands and flood-prone areas. Doing so will not only protect clean water and fish and wildlife habitat, but also will keep people out of harm's way and protect residents from flooding, erosion, mudslides and property damage.
We weaken land protections at our own peril.
The personal safety and many other benefits that healthy wetlands and rivers offer to communities are clear.
Our elected officials 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.
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