Division of Water Floodplain Mapping Webpage Update on Indiana Department of Natural Resources Website

(UNDATED) – The August 2019 update of the Best Available Flood data has been completed, according to the Indiana Department of Natural Resources

Data has been updated for the following counties can be found on the DRN website:

  • Boone
  • DeKalb
  • DuBois
  • Elkhart
  • Jasper
  • LaGrange
  • Montgomery
  • Newton
  • St Joseph
  • Steuben
  • Wells

Please proceed to this site to download the data or to access a link to the REST service at https://www.in.gov/dnr/water/9846.htm

The Engineering Service Center of the Indiana Department of Natural Resources, Division of Water, provides engineering and technical support in support of Floodplain Management in Indiana.

The three Engineering Services Basin Sections (North, Central, and South) develop hydrologic and hydraulic models and floodplain maps, review technical models submitted for permits and floodplain assessments and evaluate proposed alterations to National Flood Insurance Program studies. 

Additionally, as a Cooperating Technical Partner with FEMA, the three Engineering Services Basin Sections are continuously identifying, delineating and updating flood hazard areas, including floodway, flood fringe, and floodplain for all the counties in the State. 

This information will be used to update the Flood Insurance Studies (FIS) and Flood Insurance Rate Maps (FIRMs) in a digital format. The new flood maps will allow the state, counties, and municipalities to administer a floodplain management program to decrease existing flood damages, mitigate future flood damages, and promote the health, safety, and general welfare of the people of Indiana.

Indiana Floodplain Mapping Quick Links

Floodplain Management Links

Hydrology Links

  • The Indiana Peak Indiana Peak Discharge Determination System 
    Launch IPDDS, the Division of Water’s hydrologic computation system.  Includes directions on how to submit information to the Division for approval.
  • USGS Streamstats 
    StreamStats for Indiana incorporates regression equations for estimating peak-flow frequency statistics at the 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals (equivalent to the 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities, respectively) for unregulated streams throughout Indiana, and equations for estimating bankfull-channel dimensions of width, mean depth, and cross-sectional area for non-urban wadeable streams in the three largest physiographic regions of Indiana.
  • Coordinated Discharges of Selected Streams in Indiana
    By a Memorandum of Understanding of May 6, 1976, the U.S. Soil Conservation Service (now known as the Natural Resources Conservation Service), the U. S. Geological Survey (USGS), the U. S. Army Corps of Engineers (Louisville, Detroit and Chicago Districts) and the Indiana Department of Natural Resources (IDNR) mutually agreed to coordinated discharge-frequency values for use in water resources investigations and planning activities in the State of Indiana.
  • NOAA Atlas 14 Point Precipitation Frequency Estimates 
    Estimates of rainfall depths and distributions for various return periods throughout the state.
  • Estimation of Peak Discharges of Indiana Streams By Using log Pearson (III) Distribution:  
    Predictive equations developed for estimating peak flood for specified frequencies for streams in Indiana.
  • Drainage Areas of Indiana Streams
    Drainage areas for all Indiana streams having a drainage area of at least five square miles are determined. Drainage areas at many other points, including entry and exit points for larger streams crossing the Indiana border, were also determined.
  • Probable Maximum Precipitation Estimates  
    Charts of Probable Maximum Precipitation for Indiana derived from National Weather Service publications.
  • Purdue Long-Term Hydrologic Impact Analysis  
    Purdue Long-Term Hydrologic Impact Analysis (LTHIA-IN) is a website that can be used to delineate watersheds and determine peak discharges using NRCS TR-55 methods.

Hydraulics Links

Other Floodplain Data