Flood Plain Management

Map Modernization

The Department of Ecology continues to support ongoing updates to existing Federal Emergency Management Agency (FEMA) floodplain mapping and risk reduction programs. Ecology’s Floodplain Management Program has partnered with FEMA under two Federal Emergency Management Agency (FEMA) programs; Map Modernization & RiskMAP in support of effective implementation of floodplain regulations and flood hazard reduction.

FEMA’s Map Modernization Program: Objective is to update and modernize maps that predict where major floods are likely to occur. Map Modernization is a cornerstone for helping States and communities to be better prepared for flood disasters. Not all of Washington State’s high hazard areas are being updated.

In addition to continued support of Map Modernization & RiskMAP, Ecology’s Floodplain Management Program is actively pursuing other activities and elements to advance the technical information and expertise of future floodplain management practices. Some of these activities include:

  • Acquire precision topographic data

Precision topography is a key component to detailed mapping. Several State and local agencies are partnering on the acquisition and application of digital topography at the project level. High-precision digital topography currently exists in most flood-prone of the State and the interests and applications are increasing. State could invest in a regional data acquisition plan to fund the acquisition of digital topography and collect perishable data.

  • Collect perishable data to support risk mapping and assessments

The applications of GPS and aerial photography are valuable in calibrating and refining flood risk assessments. FEMA is taking advantage of verifiable data versus results from modeled scenarios in risk assessments.

  • Improve the ability to assess future conditions and built environments using FEMA programs, tools, and damage estimation and loss avoidance studies using HAZUS.

HAZUS: FEMA Program for Estimating Potential Losses from Disasters: HAZUS-MH is a powerful risk assessment software program for analyzing potential losses from floods, hurricane winds and earthquakes. HAZUS-MH Flood Model will carry out a wide range of flood hazard analyses, including; Studies the exposure to buildings and population from the resultant flooding, losses from flooding, and multiple scenarios which allow users to evaluate the consequences of specific actions, such as the introduction of flow regulation devices, acquisition of flood-prone properties, and other mitigation measures.

Broaden flood hazard mapping to better communicate risk. Develop maps and tools focused on risk communication and mitigation. Actions could include working with local governments to develop new risk communication products such as:

  • watershed-based cumulative risk maps

  • maps that include 10 & 50 year event scenarios

  • maps of areas protected by levees

  • levee breach scenarios

  • maps of flood claims

  • channel migration and erosion area maps

  • deep and fast flowing water

  • maps of flood depths

  • flood predictive modeling

  • maps and locations of repetitive damages

  • updated coastal velocity zone maps

  • dam failure inundation maps


Map Modernization Status


Download map (PDF)

State map of modernization status