Risk MAP Success Story: Blaine County, Idaho: A Reservoir of Effective Communication

This page describes the successes that came about from implementing the Risk MAP process at Blaine County, Idaho. It is intended for state and community officials, mitigation and urban planners and other individuals interested in how the Risk MAP program and project cycle can benefit their community in identifying and mitigating flood hazards.

In 2011, as part of a Risk MAP analysis of the Big Wood Watershed in Idaho, FEMA performed Discovery in several counties in the south-central part of the state, including Blaine County. FEMA’s Discovery is an effort to more fully engage communities during the flood mapping needs evaluation process. At the close of the Big Wood River Discovery effort, an additional study of the watershed was not funded.

However, while further analysis of the watershed was not authorized, following Discovery, a review of comments and feedback from county officials indicated that they had serious concerns regarding the current accuracy of the study for the Magic Reservoir. The Special Flood Hazard Area (SFHA) for the reservoir used on the 2010 revision, shown on the Flood Insurance Rate Map (FIRM) as a Zone A, had been redelineated based on very coarse topography during FEMA’s earlier Map Modernization program. The county was very unhappy with the 2010 changes to the floodplain limits and desired a new study to resolve the matter.


Unfortunately, neither Light Detection and Ranging (LiDAR), a remote sensing technology used to determine elevation, nor funding was available to update the FIRM in the area around Magic Reservoir. However, further conversation with county officials revealed that their concerns regarding the delineation of the SFHA for the reservoir could likely be  addressed using FEMA’s Letter of Map Revision (LOMR) process.

To begin the revision, the county-funded a local engineer to establish a Base Flood Elevation (BFE) for the reservoir. Once the community adopted the BFE, ground-based surveying was then used to establish the spatial extent of the newly developed BFE around the reservoir. With the assistance of the FEMA Region X Regional Service Center (RSC), this data along with other required information was submitted at no cost to the community for review as a FEMA-sponsored LOMR. With the RSC’s guidance, the project was shepherded smoothly through the review process. The Magic Reservoir LOMR was completed in August 2013.


Through this cooperative Risk MAP effort, Blaine County and property owners impacted by the reservoir now have a far more accurate tool in the new BFE for use in planning and mitigating the risk of flooding in the area. The county’s concern regarding Magic Reservoir was an issue that FEMA had not been aware of before the Discovery process. Through Discovery, the right connections were made to resolve the problem with a relatively small monetary investment by the county and FEMA. These watershed efforts exemplify the Risk MAP program mission: collaborative process, quality data, mitigation planning and action, leading to risk reduction.

Risk MAP Project Phases

During Discovery FEMA seeks to establish working relationships with local communities to gather information about local flood risk and flooding history, review mitigation plans, work with communities on developing a future vision for their watershed, and lastly, use the collected information and feedback to determine which areas, if any, of the watershed require further mapping, assessment, or mitigation planning through continued Risk MAP engagement. This success story is relevant to the Risk MAP project phases listed below:

  • Mapping and Data
  • Community Engagement, Outreach, and Education
  • Partnerships
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