General Guidelines for the Hydrologic-Hydraulic Assessment of Floodplains in Indiana was created to assist the floodplain management community in establishing base flood elevations and floodway limits and in evaluating projects in accordance with the Indiana Flood Control Act and the National Flood Insurance Program. The guidelines detail methods acceptable to both the Indiana Department of Natural Resources (IDNR) and the Federal Emergency Management Agency (FEMA) with respect to hydrologic and hydraulic modeling and floodplain mapping. Also included in this guide are recommendations on presenting results of a floodplain study and other useful reference material.
- Executive Summary
- Chapter 1: Introduction (Updated March 2015)
- Chapter 2: Obtaining a Floodplain Determination for a Minor Site Assessment (updated August 2014)
- Chapter 2.5: Non-modeling Assessment Approaches Used by the IDNR (updated June 2014)
- Chapter 3: Overview of the Process for Performing a Detailed Floodplain Analysis (updated August 2014)
- Chapter 4: Mapping Standards and Methods (updated December 2014)
- Chapter 5: Surveying Standards and Methods (updated June 2014)
- Chapter 6: Researching and Evaluating Existing Models (Updated March 2015)
- Chapter 7: Guidelines for determining peak discharges
- Chapter 8: Guidelines for Hydraulic Modeling Using HEC-RAS (updated August 2016)
- Chapter 9: Guidelines for Alternate Hydraulic Models (updated February 2016)
- Chapter 10: Presentation of Modeling Results (updated October 2014)
- Bibliography
- Appendices (under construction)
- Hydraulic modeling checklist (updated June 2014)
Web links featured in the report
- Chapter 1: Introduction
- IDNR / Division of Water Web site
- Indiana Floodplain Mapping
- Indiana Flood Control Act (IC 14-28-1)
- Indiana Floodplain Management Act (IC-14-28-3)
- Floodplain Management Rule (312 IAC 10)
- Criteria for land management and use (44CFR Part 60)
- Identification and mapping of special hazard areas (44CFR Part 65)
- Appeals from proposed flood elevation determinations (44 CFR Part 67)
- Procedure for map correction (44 CFR Part 70)
- Chapter 2: Obtaining a Floodplain Determination for a Minor Site Assessment
- Chapter 2.5: Non-modeling Assessment Approaches Used by the IDNR
- FEMA Map Service Center
- INdiana Floodplain Information Portal
- Division of Water Regulatory Permit Programs and Related Information
- Non-Modeling Hydraulic Assessment Worksheets and Companion Worksheets:
(under “Technical Requirements: Minimal Application Submittal for Construction in a Floodway”) - Construction in a Floodway Assessment User Guide, Worksheet Examples and Training Videos
- Permit Application Database
(under "Other Permit-Related Resources and Information") - Floodway Habitat Mitigation Guidelines
- Chapter 3: Overview of the Process for Performing a Detailed Floodplain Analysis
- IDNR Division of Water
- Indiana Hydrology and Hydraulics Model Library
- Accuracy of Computed Water Surface Profiles
- Reach length equation Section 3.5.1
Hydraulic Design Manual, Larry Mays, Chapter 19 - FEMA MT-2 forms
- FEMA Part 65 of NFIP (LOMR and CLOMR)
- Chapter 4: Mapping Standards and Methods
- IDNR “Floodplain” Mapping
- IU GIS Portal
- USGS Mapping
- IUPUI Historical Aerial Archive
- IGS Indiana Historical Aerial Photo Index
- Indiana Commission of Public Records -- Aerial Photographs
- FEMA Guidelines and Specifications for Flood Hazard Mapping Partners
- FEMA Map Service Center
- The Indiana Flood Data Management System
- Chapter 5: Surveying Standards and Methods
- OPUS - Online Positioning User Service / National Geodetic Survey
- U. S. Army Corps of Engineers Topographic Engineering Center (Corpscon)
- IDNR Benchmarks for Indiana
- FEMA Guidelines and Specifications for Flood Hazard Mapping Partners
- Ohio River Datum (Sandy Hook Datum)
- Chapter 6: Researching and Evaluating Existing Models
- Chapter 7: Guidelines for determining peak discharges
- Hydrology And Hydraulics In Indiana (Volume 1) (Neyer)
- Drainage Areas of Indiana Streams (Hoggatt)
- USDA / NRCS Geospatial Data Gateway
- USGS / Streamstats
- Purdue University / OLWS
- NOAA Atlas 14 Precipitation Frequency Data Server
- NOAA Atlas 14 Temporal Distributions of Heavy Precipitation
- Coordinated Discharges of Selected Streams in Indiana
- Flood Frequency Relationships In Indiana
- Indiana Peak Discharge Determination System
- Guidelines For Determining Flood Flow Frequency (Bulletin #17B)
- Urban Hydrology For Small Watersheds (TR-55)
- Regional Regression Equations to Estimate Synthetic Unit
Hydrograph Parameters for Indiana - Indiana LTAP / Stormwater Drainage Manual
- HEC Hydrologic Modeling System (HEC-HMS)
- WinTR20 (NRCS)
- Indiana State Climate Office (Purdue)
- National Climatic Data Center (NCDC)
- General Guidelines for New Dams & Improvements to Existing Dams in Indiana
- Chapter 8: Guidelines for Hydraulic Modeling Using HEC-RAS
- Federal Highway Administration Hydraulic Design Series 7 (HDS 7)
- HEC-RAS Hydraulic Reference Manual
- Hydrologic Engineering Center
- Notes on Critical Depth messages
- HEC-2 troubleshooting guide
- Roughness Characteristics of Natural Channels (Barnes, USGS 1849)
- Reference tables for Manning’s N Values
- Check-RAS (FEMA)
- Chapter 9: Guidelines for Alternate Hydraulic Models
- One-Dimensional Unsteady and Two-Dimensional Models: Issues for Regulatory Use
- XPSWMM
- ICPR
- Hydrologic Engineering Center (HEC-RAS)
- Hydrologic Engineering Center (HEC-2)
- HecRAS
- E431
- WSPRO
- Chapter 10: Presentation of Modeling Results
- Appendices
- FEMA Letters of Map Revision
- Flood Control Projects
- Levees
- Flow Chart: Overview of Floodplain Analysis
