Our Views: Benefits of Chehalis Basin Process Reach Beyond Lewis County


The Chehalis Basin process includes projects for fish recovery and flood protection in every community along the river. 

One of the most important projects is the proposed North Shore Levee including the west extension to protect Aberdeen and Hoquiam from floods, sea level rise and future tsunamis. Today, thousands of homeowners in those communities cannot get federal flood insurance because their properties sit exposed to these threats. 

Without flood insurance, those homes and small business owners cannot get loans on their properties, they cannot refinance, and they cannot sell. This has resulted in a gigantic collective drop in property value for these property owners and for the entire community in turn. This crisis for the Twin Harbor communities has devalued entire neighborhoods and significantly reduced revenue to fund basic services through the cities of Aberdeen, Hoquiam and Grays Harbor County. 

The Chehalis River is only one contributor when catastrophic flooding occurs in Aberdeen and Hoquiam. Those communities sit at the end of the Chehalis River where it enters Grays Harbor and then the ocean. Water retention in the upper basin, holding 65,000 acre feet of flood water above Pe Ell, reduces the peak of a 100-year flood in the Chehalis River main stem by half of a foot as far downstream as Cosmopolis. It can have a positive impact of reducing the flood peak further downstream in Aberdeen, but there the tidal influence becomes a greater factor than the river level. 

The project that can provide the direct benefit to Aberdeen and Hoquiam is the proposed North Shore Levee project including its west extension. We see this project as a critical component to the Chehalis Basin strategy along with hundreds of miles of salmon habitat, water retention, restricting future growth in the floodplain and local projects. 

Already every community in the basin has benefitted by engagement in the Chehalis Basin process. In Gray Harbor alone, over $32 million in projects protecting homes, schools and businesses have been completed on time and on budget. In Grays Harbor County, these projects have been located in Montesano, Oakville on the Chehalis Reservation, Cosmopolis, Aberdeen and Hoquiam. The list is long in Lewis and Southern Thurston counties also. 

Throughout the Chehalis Basin process, many ideas for flood protection and fish enhancement have been proposed. Sometimes it almost seems that there are as many ideas as there are people in the basin. But methodically using the best science along with local input, these ideas have been evaluated and either adopted, modified or set aside. 

Last week, we saw a letter proposing an old idea: create more flood storage in the floodplain along the river above Chehalis and Centralia. Recently, a hydrologic analysis was done through the office of Chehalis Basin showing that there is a grand total of 500 acres of unused floodplain along the main stem of the Chehalis river, meaning land on the valley floor that isn’t already covered with river water during a catastrophic flood. Adding 500 acres of new storage, when catastrophic flows have reached 300,000 acre feet of water, is obviously not an idea that will add a measurable amount of flood protection for families and communities in the Chehalis basin. 


This is an installment of an ongoing series focusing on the proposed dam on the Chehalis River. Installments will be published in each Saturday edition of The Chronicle.