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Flood Management

   US 12 - Naches River flood plain
US 12 - Naches River Flood Plain
WSDOT owned and managed infrastructure often intersects floodplains. Flooding adversely impacts transportation facilities, disrupting services, interrupting the movement of people and goods. 

The construction and maintenance of WSDOT facilities can also affect the capacity of floodplain storage and watershed function, and may have a negative impact on natural resources. 

It is generally more cost effective to prevent flood damage than to repair; and local communities expect WSDOT to help solve the flood management problem.

The WSDOT Flood Management Initiative is intended to reduce transportation infrastructure closures, damage, environmental and economic losses that are associated with flood emergencies, and to improve WSDOT’s watershed-based flood management capabilities. The 1998 Legislature enacted Substitute House Bill 3110 (SHB 3110), temporarily codified as Chapter 181, Laws of 1998.

The initiative recognizes flooding as:

  • a public safety issue
  • a transportation issue
  • an economic issue
  • a salmon recovery issue
  • a watershed issue

Actions within the initiative are designed to address these issues. 
Primary actions include:

  • Working with other agencies to improve coordination
    (SHB 3110 Committee on Floodplain Management Coordination) 
  • Working with local government to resolve critical flood issues (Chehalis Basin Flood Hazard Reduction Project)
  • Creating a flood database to track flood repair and flood hazard reduction efforts
  • Building a predictive model that integrates hydrologic, hydraulic, environmental and land use data to help guide basin-wide planning processes 
  • Developing watershed-based, salmon-friendly internal guidance for WSDOT flood hazard reduction and emergency flood response 
  • Developing and testing an agency flood management strategic plan and/or pilot basin planning project.

WSDOT Flood Initiative Manager: Jim Park (


Floodplain Management 

Substitute House Bill 3110 Committee on Floodplain Management Coordination

Information and interagency coordination critical to effective watershed management and planning is not readily available.  This is particularly true in the area of floodplain management and flood hazard reduction planning.  Flood management has gained significant scrutiny by the state Legislature in the last few years.  Nearly $400 million dollars have been spent since 1996 to repair the damages caused by these events.  

The Washington State Legislature directed state agencies to seek a coordinated approach to flood management through SHB 3110.  This legislation directed WSDOT and the Department of Ecology to convene a committee of state and federal agencies, tribal and local governments to identify opportunities for improved coordination on floodplain management.  

The committee made a series of recommendations and was awarded $500,000 by the Legislature in fiscal year 1999 (reduced to $200,000 as result of voter passed Initiative-695) to begin to implement the following recommendations:  

  • Administrative Recommendations: Improve access to information; Identify a lead agency and establish a floodplain management task force; Improve access to funding for hazard reductions; Establish environmental mitigation standards; Increase technical assistance; Review flood models; and, Expand and update floodplain mapping.

  • Legislative Recommendations: Implement enhanced flood planning; and Improve land use planning.

SHB 3110 Actions

Initial actions have included the development of a Cooperative Technical Community (CTC) to facilitate improvements in floodplain mapping process, and, as funding allows, updated floodplain mapping data for pilot basins. 

The committee will continue to serve as a coordinating body, for prioritization of funding for statewide mapping update activities from anticipated FEMA funding, and will seek ways to streamline processes and improve flood emergency response.


Jim Park, co-chair, WSDOT Flood Initiative Manager
Jerry Franklin, co-chair, Washington Department of Ecology

SHB 3110 Committee Members

WSDOT and Washington State Dept. of Ecology, co-lead; Community Trade and Economic Development, Washington Dept. of Fish and Wildlife, Dept. of Natural Resources, SRO, EMD (with federal partners, FEMA and Corps; local government partners, Counties and Cities; Tribal Governments (Skokomish Tribe).