"It's just blind ignorance to keep (fillin in the floodplain)."

Tammy Baker,
Newaukum Valley resident

By John Henderer
The Chronicle

Before any more dams or dikes are added to control flooding in Lewis County, government officials will scrutinize local policies that allow filling in the 100-year floodplain.

On Monday, county commissioners both rejected a petition to create a proposed flood control district and pledged to address the filling issue. Filling involves the use of dirt or rock as a foundation for a building to raise it above the floodplain.

Commissioners will discuss filling in the floodplain Saturday, during a regularly scheduled Tri-Agency Meeting with city officials from Centralia and Chehalis. The meeting at the County Courthouse Annex, 345 W. Main St., Chehalis, starts at 8 a.m. and goes to 12:30 p.m. Other meeting topics include solid waste, growth management and waste water.

Promoters of the proposed Chehalis River basin district for Lewis County advocated building dams and excavating part of the river.

Official talks follow a drumbeat of pleas for action from citizens during recent public hearings on the proposed district.

"It's just blind ignorance to keep on doing it (filling in the floodplain)," said Tammy Baker, a Newaukum Valley resident who is suing the county over an approved floodplain development permit near her property.

Others called for a "moratorium" on filling in the floodplain.

Despite perceptions, recent filling may not have a direct relationship on the severity of flooding, county and city officials said.

"You look at the mass of the area that we have, and the area that has been filled is probably pretty insignificant," said Dennis Sabin, Lewis County building official. "(Citizens) have the idea that it's like dropping rocks in a bathtub: Eventually it's going to run over. But it's really different: It's running water."

Existing regulations in Lewis County and the Twin Cities allow filling in the floodplain. Developers must receive an approved floodplain development permit for such filling and a State Environmental Policy Act (SEPA) permit if the filling exceeds 500 cubic yards or 50 dump truck loads.

The floodplain permit requires developers to note whether their development is in a floodway or floodplain and how the site elevation compares with the floodplain elevation.

Floodways are areas officially designated by the U.S. Army Corps of Engineers where floodwaters are supposed to travel; they usually closely follow a riverbed and represent less acreage than the floodplain.

The floodplain is a larger area that has the likelihood of flooding every 100 years.

The floodway near the confluence of the Skookumchuck and Chehalis rivers is probably 600 feet wide, according to Terry Calkins, Centralia community development director. Near China Creek, which bisects the city diagonally, it's probably 20 feet wide, Calkins said.

The floodplain includes about one third of the city of Centralia. "There's a significant amount of our floodplain that has not been developed," Calkins said.

Development, and unlimited filling, is allowed in the floodplain because the Corps of Engineers determined this will not raise the height of a flood more than one foot, an elevation politically tolerated, Calkins said.

Centralia bars development in floodways, however, where filling could have a more dramatic impact.

"That's where the line is drawn in the sand," Calkins said. "As long as they stay out of the floodway, it's already been calculated - it's one foot (elevation increase) or less (that's allowable)."

A Corps of Engineers official expressed less confidence in the flood insurance rate maps his agency produced in 1981, using data from the late 1960s and early 1970s.

"We just don't know (the effects of filling in the floodplain)," said Dan Harvey, chief of the Corps of Engineers' hydraulic engineering section in Seattle. "Obviously, probably (there is) a little."

Several weeks ago the corps received orders from the Federal Emergency Management Agency to produce a new, more sophisticated hydraulic modeling study of floodwaters of the Chehalis River between Grand Mound and Adna. The study, which got $35,000 in FEMA funding, should be done by June, Harvey said.

"It's something we've been wanting to do down there for a long, long time," he said. "We haven't had the money for it."

County regulations allow floodway development if certain conditions are met, but they bar filling in floodways.

Development in the floodplain increased dramatically last year in Lewis County and Centralia while it remained about the same within the city of Chehalis.

Lewis County issued 59 floodplain development permits last year, nearly an 80 percent increase over the prior year. Centralia issued 53 permits last year, nearly a 100 percent increase.

County Commission Chairman Richard Graham expressed reluctance to immediately ban filling in the floodplain.

"As far as I'm concerned, most of the filling that's going on around here is in the cities," he said. "We might be stomping on somebody's property rights. I don't think there's enough money to buy up everybody's development rights."