Lessons from another year of Puget Sound flooding must be embraced

THIS isn't the first time Puget Sound rivers have flooded, and it most certainly won't be the last. Perhaps it's time to start asking why.

First, some facts. Four rivers in our region experienced record flood levels this week. Twelve rivers had major flooding, and another seven had minor to moderate flooding. Even minor flooding is a problem if the water ends up in your living room.

And let's not forget that Interstate 5 is underwater and shut down for the second time in two years. Washington state Department of Transportation estimates the cost of the December 2007 storm, which closed I-5 and other roads for four days, was $62 million in repairs due to storm damage and $47 million in freight-related impacts. How much will it cost this time? And the next?

There are a variety of reasons for the recent rash of destructive flooding, some less obvious than others.

The most obvious reason is that our climate is changing. Global warming is a term that doesn't quite describe what's really happening. A more appropriate term might be climate disruption. Our climate is becoming more volatile and more variable, leading to extreme weather events and increased weather-related disasters.

This winter, we broke multiple records for high temperatures in November, followed in December by multiple records for low temperatures and a paralyzing snowstorm. And then in the course of a few days in January, the temperature rose more than 20 degrees, leading to rain, quickly melting snow and our current flooding disaster.

We should expect more of this wacky weather in the future. As the climate changes and becomes less predictable, we are likely to get more extremes, including more rain and less snow, increasingly severe storms, and even more record floods.

There are two actions we must take to address climate change. First, we must cap and significantly reduce our carbon emissions. To do that, we must pass Washington state's cap-and-invest legislation this year and also pass a similar bill at the federal level to curb global-warming pollution. Second, we must invest in clean energy, efficient buildings and vehicles, and green jobs to increase options for minimizing carbon emissions.

The less obvious reasons for the region's repeated flooding problems are loss of natural floodplains and reliance on engineered stormwater systems.

Storms wouldn't be such a problem if we kept our buildings and communities out of floodplains. Floodplains are nature's way of managing stormwater — think of them as built-in safety valves. They absorb excess flow, slow it down, and help trap impurities before they reach the Sound. However, instead of allowing natural systems to manage stormwater, we've destroyed floodplains, built levees, channeled rivers, and constructed concrete stormwater systems that are typically designed to handle a 100-year flood. Unfortunately, our current 100-year flood levels are being surpassed year after year. With climate change and record flooding, we are now paying the price for our misguided treatment of floodplains.

Although federal and state laws are supposed to protect floodplains, it turns out that the most influential federal policy on floodplain protection, the National Flood Insurance Program, actually encourages development in floodplains by insuring losses for structures built in flood-prone areas. Fortunately, a successful lawsuit filed by the National Wildlife Federation led to a recent decision requiring changes to the National Flood Insurance Program. If implemented appropriately, these changes will help keep people out of harm's way, reduce costly flood-damage claims, and also improve water quality and habitat for fish and wildlife.

While the mandated changes must be implemented, they won't be enough to prevent devastating and costly flood damage in the future. The Puget Sound region must prepare for stronger and more frequent storms, and it must rethink how it manages stormwater. This will mean updating many of our state and local codes, regulations and laws to incorporate the impacts of climate change.

Many of these impacts, including sea-level rise, flooding and reduced snowpack, are already being felt. Their effects will only become more pronounced over time.

We must also rely more on natural approaches to managing stormwater, not only preventing development in sensitive areas, but also encouraging low-impact-development approaches that enhance the land's natural ability to absorb, cleanse and manage stormwater. Our goal should be to create a sustainable, systems approach to managing stormwater that benefits the environment, reduces costly flood damage, and protects human health and communities.

This won't be the last time massive rains hit Puget Sound. Perhaps its time to start doing something about it.