Protecting I-5 and residents occupying the Chehalis River, Washington floodplain may provide an opportunity offer additional benefits.
In Chapter 8 of Floodplain Management we offer a case study concerning protecting Interstate 5 from flood damage.
For those who have not read the chapter during the first week of December 2007, record-setting precipitation dumped on the Pacific Northwest. Torrents of water-gouged hillsides broke levees and overtopped dikes as floods reached record highs. One man was swept away in the deluge. The I-5 freeway in Lewis County, Washington was closed for three days and traffic was rerouted an extra 400 miles. The Department of Transportation estimated the cost of the I-5 closure exceeded $4 million per day.
The Chronicle (Lewis county Washington) editorial board in “OUR VIEWS: Our State Reps Push for Water Retention” (October 30, 2009) stated that water retention deserves a chance if studies bear out its effectiveness. And beyond flood protection, water retention has the possibility of improving water quality in the river, enhanced fisheries, agricultural benefits and expansion of recreation. Currently the Army Corps is only focusing on building 11 miles of levees that might protect Interstate 5 during big flooding events, and perhaps parts of the Twin Cities, but certainly would not help out in other areas along the Chehalis River
Not mentioned were expected impacts from Climate change. The Climate Impact Group (CIG) and the International Panel on Climate Change (IPCC) project increases in winter rain quantity and intensity leading to greater flooding. And, increasingly, summers will be hotter and dryer contributing to drought. These changes are being notice now.
Retention alternatives could reduce winter discharges while increasing summer ones.
Can flood reduction efforts resulting from the 2007 incident be viewed as an opportunity to address expected climate change impact?
