Legislators hear Steamboat Sl. dike repair needs

Local officials last week enlisted the help of District 19 members of the Washington State Legislature in finding support for repairs of the eroding Steamboat Slough Dike.

The Columbia River has been eating into the bank below the dike, which protects the Julia Butler Hansen National Wildlife Refuge for the Columbian White-tailed Deer, and Wahkiakum County officials have closed the road because of a potential for a landslide that would take out the dike and road.

The dike is no longer in the US Army Corps of Engineers dike maintenance plan, and neither the Corps, USFWS, diking district or county have funds to repair the dike.

County Commissioner Lisa Marsyla convened a meeting May 2 with USFWS officials and State Senator Brian Hatfield and State Representatives Brian Blake and Dean Takko to discuss the situation.

A dike breach would lead to flooding of the refuge and probable flooding of SR 4 on the back side of the refuge, Marsyla said.

She added that Washington Department of Transportation officials haven't been involved in discussions but should be. If there were a threat to the highway, the Corps might be able to find funding for repairing a breach she said. Flooding from the Elochoman River closed the highway in 1996 and 2009, she said.

The representatives said they would contact WSDOT officials and urge them to take part in the discussions.

Mark Wharry, a consulting engineer engaged by USFWS, explained how the erosion is proceeding. His firm has done surveys and used sounding data to analyze the threat.

The dike and SR 4 both have an 11' elevation, he said, and the 100 year flood level is a bit over 10', so the highway would be impacted, possibly closed, in severe flooding, he said.

Sounding shows the river has eaten into the bank just at the downstream end of bank reinforcement done in the 1990's when similar erosion occurred.

The firm has identified several options for addressing the problem and developed rough estimates of their costs. The options and rough cost estimates include:

1. Using riprap rock to plug the hole and armor the bank; $3 million.

2. Building a new section of levee set back 100'; this should give good protection, Wharry said. Estimated cost is $2.75 million.

3. Building a new levee section along the existing, threatened portion, and driving sheet pile into the ground for protection against slides; $4.5 million.

4. Building a new section of levee 120-200' back from the existing levee and in effect building a beach between the levee and the river, $3.25 million.

5. Building a new levee section along the existing, threatened portion, and driving sheet pile into the ground for protection against slides, but removing the road, thereby ending public access to the area, $3.5 million.

A possible funding source is Economic Development Administration block grants for disaster relief and job creation, commented Jennifer Keene of the Cowlitz/Wahkiakum Council of Governments. She said she would investigate this possibility.

The group said they would meet again in June to discuss what they've learned by that time.