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 WHAT is a Flood Risk Assessment?

A Flood Risk Assessment aims to create information in order to better understand and estimate the real impacts of different flooding events. This project will map and analyze flood damage risk on a structure-by-structure basis. Structure specific survey information will help estimate the amount of risk an area could face in the event of a flood. This Risk Assessment will send surveyors in and around your community to map and document properties in the floodplain, and their potential risk for flood damages.

 WHY is this project being conducted?

Flooding impacts can vary greatly depending on how well a community is prepared and how up-to-date available information is when it comes to inundation mapping. This project will help communities and their residents become better informed and determine optimal solutions for flooding issues.

 HOW is the assessment funded?

Federal funds and state in-kind services.

 WHAT authority gives the survey crew access to my property?

The survey crew is acting under the authority of a professional land Surveyor with the Illinois Department of Natural Resources - Office of Water Resources.  Illinois law (225ILCS 330/5) gives Professional Land Surveyors, or persons under their direct supervision, the right to enter private property in the course of surveying structures with respect to floodplain mapping.

 WHAT impact will this project have on me and my property?

Over the course of the project, surveyors will be sent to your community and onto and around your property to survey and document your property’s potential flood risk. Surveyors will be clearly marked and will carry identification and surveying equipment with them. They will also be using photography equipment around your property to assist with the creation of a structural flood risk inventory. There will be no impacts to your utility services.

 WHAT information is being collected?

Surveyors will be acquiring first floor (front door sill), lowest entry (window vent or crawl space) and typical ground elevations on your property. This specific information will help estimate the potential flood threat and damages to your home or business.

 WHEN can I expect to see surveyors on my property?

Check the “Schedule” portion of this page for updates on when to expect surveyors in your community.

 WHO should I contact if I have questions?

If you have questions about the Flood Risk Assessment project, including timeline, logistics or impacts on you and your community, feel free to contact the U.S. Army Corps of Engineers Rock Island District at 309-794-5729 or the Illinois Department of Natural Resources - Office of Water Resources at 217-782-4544.

 WHY are photos required for the project?

The analyses of potential flood losses is a function of the type of structure. The photo helps ensure proper interpretation of the surveyed elevations and the GIS, assessor, and elevation certificate data collected.

 WILL a record of the data gathered for my property be provided to me?

At this time, the information is being shared with state and local officials only. After the study is complete, you are welcome to contact your local floodplain manager to request a copy of the information.

 WILL the information collected be used by the Flood Insurance Program to raise insurance rates?

No. The information collected will provide local and state officials with information on flood risk.


November 2023: Project Start
May – October 2024: Survey of structures
May – October 2024: Hydraulic flood modelling
October 2024 – February 2025: GIS Analysis
February – April 2025 – Interagency Review
May 2025: Project completion

Contact Us

U.S. Army Corps of Engineers Rock Island District: 309-794-5729
Illinois Department of Natural Resources - Office of Water Resources: 217-782-4544.

Lower Rock River Flood Risk Assessment

The USACE Rock Island District, Illinois Department of Natural Resources - Office of Water Resources and Illinois State Water Survey are partnering to examine flood risk on the lower Rock River. This inter-agency project will develop and communicate structure-based flood risk assessments for communities on the lower Rock River in Henry, Lee, and Whiteside counties. See Map Below

This work will provide maps for Rock River communities to better communicate flood risk and help plan for future flooding. Structural flood damage assessments will be developed for all areas in the floodplain that are considered to be at risk based on annual flooding statistics. These assessments will be developed using various flood depths and will include survey data collected from the lowest elevation water can enter a building and first floor elevation for all residential, commercial, and industrial structures. Parcel data, Geographic Information System (GIS) data, and any elevation certificate data will be obtained from each county and municipality.

Lower Rock River Project Map

Project Benefits

  • As a result of this project, state, county and local community officials will have access to enhanced flood risk information and tools to assist with community communication and decision-making regarding land-use and future development in high-risk flood areas.
  • Information shared with river communities will be used to inform and educate citizens about flood risk.
  • Flood risk assessments like this, recently conducted in Illinois on the Upper Mississippi River and Illinois River have already yielded immediate life safety and resiliency benefits as well as improved planning for the future.
  • This project will add another complete component to the growing statewide risk assessment database being developed and used by the State of Illinois.