Federal, state, county and city officials have gathered information from early-December flooding that will be used to help create new maps defining the Chehalis Valley flood plain, according to FEMA officials.
The Dec. 3 flooding halted a map-updating process that FEMA representatives said had begun in 2005. The previous maps had not been updated since 1981, and many areas outside the defined flood plain have been flooded in recent years. But now data retrieved during and after the floods may be utilized in the renewed map-making process.
New maps will be available in months, not years, according to FEMA officials, though there is still no date set for release.
In order to know where the water will go, you need to know how much water is in the river, said Ryan Ike, chief of FEMAs risk analysis branch in Region X. Once you have that water you can run the hydraulic model through the system … then plot that on a topographical map.
Updated Information
Flood maps, produced by FEMA, provide vital information for setting flood insurance rates and building codes, he said. Though lack of federal funding had kept the previous flood plain maps from being updated since 1981, Ike said that old analysis is not necessarily bad analysis, adding that there are thousands of flood maps that identify risks across much of the country, and many of those have not been updated in decades, either.
Few Lewis County Residents Have Flood Insurance
By The Chronicle
Despite many common misconceptions, FEMA officials say every home in the nation is eligible for flood insurance, regardless of whether it is in a mapped floodplain.
However, information provided by FEMA shows very few Lewis County residents have invested in flood insurance. Below are the number of registered households in Lewis County with a flood insurance plan:
Centralia — 743
Chehalis — 235
Morton — 9
Toledo — 25
Winlock — 1
Pe Ell — 2
Vader — 1
People can get an estimate of what flood insurance might cost for them at www.floodsmart.gov, or by calling their insurance provider.
But the recent flooding gave FEMA an opportunity to utilize current data in making new maps, Ike said. The Lewis County public works department helped facilitate that opportunity by providing expedient information regarding high-water marks.
Lewis County Public Works senior survey engineer Martin Roy, along with about six other county employees, began measuring the high water marks left by the floods before the water began to recede Dec. 4.
Carefully navigating through flooded streets and blocked roadways, Roy and others used a variety of means to mark structures and log the precise locations using a global positioning system (GPS). In some locations, such as the Sunbird Shopping Center in Chehalis, a simple black X was marked at the water line on the side of the building. In others, such as the Airgas distribution office near downtown Chehalis, workers placed a wooden stake and a steel spike as a beacon for whoever ended up returning to the site. The GPS allowed them to include latitude and longitude for each location, which may provide a blueprint for various government departments that may need to return to the high water mark.
Mapping the Inundation
Our thought process was, if we save these then whoever needs these will have them, said Roy, who has worked in the public works department for about seven years. At the time, we werent quite sure of who would want them and when.
The FEMA, as well as the state Department of Ecology, both needed them, he said, and now data has been bundled and sent to those destinations.
Matt Hyatt, Lewis County public works GIS Manager, said that the cities of Chehalis and Centralia have also sent information gathered by building inspectors from damaged homes and businesses, though that information does not go through the county.
Hyatt said that, collectively, the data will be used to create the general inundation area and a depth of water grid.
Ike said that from his own experience, community involvement can vary depending on the site of the disaster.
Lewis County has taken some pretty proactive steps, Ike said.
The decision to take those steps was the result of lessons learned from the countys response to flooding in East Lewis County in 2006, Roy said.
Pinpointing Exact Locations
The next step is for FEMA, the Department of Ecology and other state and federal government bodies to use the locations of the water marks — which Roy said amount to more than 100 — to gauge exactly how high the water rose during the flooding. The important thing, said Roy, is to pinpoint the exact elevation of the water mark.
We sent them all the spots and locations that we gathered, but at that point it was just raw data, Roy said. There was a location but no elevation tied to it yet. … About a week ago we gave the FEMA folks approximately 40 points in the Centralia area where we had derived elevations.
The rest of the locations will be visited by federal and state officials who will use advanced GPS technology to establish the exact elevation, he said. After that, Lewis County public works stands ready to find the elevations of whichever locations have not been pinpointed.
It clearly became obvious that we needed to step up and have the data this time, so we did what we could, Roy said.
Eric Schwartz covers municipal government and health for The Chronicle. He may be reached at 807-8245.
