Chehalis: A Town That Floods

Chehalis, Washington sits in a river valley that floods with unusual regularity. The town and the neighboring city of Centralia just to the north have been inundated repeatedly by the Chehalis River, which drains a large watershed in the western Cascades and can rise with remarkable speed. The flood of December two thousand seven was among the worst in recorded history, closing Interstate Five for about four days, cutting off the main north-south corridor in Washington State and stranding thousands of travelers.

Entire neighborhoods sat under eight or more feet of water. The economic damage ran into hundreds of millions of dollars. The community has debated flood control infrastructure for decades, with proposals ranging from upstream flood retention dams to levee systems, each carrying significant environmental and financial tradeoffs.

The Chehalis Basin is one of the few remaining significant salmon-bearing river systems in the region, which complicates engineering solutions.