Ecology, FEMA revising state flood hazard maps

A project currently under way will help Washington landowners and local officials make informed decisions about where it is safe to build in and around areas prone to flooding.

The Federal Emergency Management Agency (FEMA) and the Department of Ecology (Ecology) are updating existing flood hazard maps in several Washington counties that have high risk, flood-prone areas.

In many Washington communities, it has been about 20-30 years since flood hazard maps have been updated. The new maps will depict flood hazards more accurately, including changes in flooding patterns.

The mapping project is part of a nationwide effort by FEMA. Ecology is helping FEMA put the new maps into a digital, electronic format. The more detailed maps will eventually be available on the Internet.

The December 3, 2007, storm in Western Washington highlighted how flooding can cause serious economic damage to dwellings, buildings and other development in communities - and trigger immeasurable social, cultural and environmental hardships.

The new digitized maps will better represent all the geographical features and hazards within a particular flood plain. The work will involve a series of engineering assessments, computer modeling, geographic information system (GIS)-based mapping, and public meetings.

The new maps will help FEMA, insurance companies and lenders determine who needs flood insurance and how much it will cost. Local jurisdictions with better land use controls for flood plains get lower premiums on flood insurance.

According to FEMA Regional Administrator Susan Reinertson, flood plains often cover more than a single county, city, town and related urban growth boundaries.

"We're continuing to improve the quality and accuracy of national flood hazard data by developing Geographic Information System-based products with the best technologies," Reinertson said. "The new digitized maps will provide communities with flood maps and data that are more reliable, easier to use and more readily available."

Reinertson said the new digital maps will help FEMA and Ecology:

• Tackle the mapping needs of communities with growing populations and high-flood risks in coastal and levee areas.

• Conduct a baseline flood risk assessment for all river drainage basins in the state.

• Ensure that plans designed to offset the effects of flood plain development are properly evaluated and provide a sound basis for any improvements to be put in place.

• Enable coordinated flood risk management activities between local, state and federal agencies.