Flood Map Modernization and North Dakota Julie Prescott, ND Map Modernization Coordinator North Dakota State Water Commission And Brian Fischer, CFM, GIS Project Manager Houston Engineering, Inc. FLOOD MAP MODERNIZATION

Flood Map Modernization  Nationwide, 5-year, $1 billion program to update FEMA’s Flood Insurance Rate Maps (FIRMs)  Used by local officials in managing development and land use planning, and also in disaster and emergency response planning  Used by lenders and agents in determining the proper protection level for their clients

Flood Map Modernization  100,000 existing panels nationwide will be modernized to a digital format, publicly available through the Internet  Will allow for timely updates to maps as flood risks change  Local engineering firms are contracted to do the mapping and determine the risk zones

Flood Map Modernization  Currently, the State of North Dakota has contracted with engineering firms to modernize maps in 11 counties: BarnesPembina Walsh BensonRamsey Grand ForksRansom MercerRichland NelsonTraill

Flood Map Modernization Acronyms  FIRM – Flood Insurance Rate MapFlood Insurance Rate Map Official map of a community on which FEMA has delineated both the special flood hazard areas and the risk zones applicable to the community  DFIRM – Digital Flood Insurance Rate Map Database that contains all information needed to produce FIRM maps  FIS – Flood Insurance Study A flood study to determine the flood hazards, and if appropriate, the corresponding water surface elevations

Flood Map Modernization FIRMs to DFIRMs  FIRMs (Old paper maps) Very outdated Difficult to update Typically no digital data Tough to use with GIS  DFIRMs (New digital data and maps) Updates maps with new data County-wide format Digital data is available in a standard database

Flood Map Modernization  Why is FEMA’s Map Mod Initiative Important to GIS Professionals? Lets you incorporate your GIS basemap data Produces a product that is better than we had previously A lot of us are asked to make decisions and maps for floodplain management Gives local communities the opportunity to review the GIS products

Flood Map Modernization Lifecycle of a DFIRM Project  months Source: FEMA

Flood Map Modernization Lifecycle of a DFIRM Project Source: FEMA

Flood Map Modernization Lifecycle of a DFIRM Project  Generally 2 routes for a DFIRM project  1.) Digital Conversion Shorter project Less Costly Used where no needs are identified  2.) New Flood Study Longer project More Expensive Generally improves flood hazard data

Flood Map Modernization Lifecycle of a DFIRM Project  GIS is Used Throughout the Project Basemap Acquisition Survey and Topographic Data (Flood Study) Hydrology (Flood Study) Hydraulics (Flood Study) Mapping (Flood Study) Preliminary DFIRM Database Preliminary Maps

Flood Map Modernization Lifecycle of a DFIRM Project  Basemap Acquistion Local data preferred Determines vector or raster based panels FEMA Guidelines and Standards  S_Perm_Bmk (NGS Benchmarks)  S_PLSS_Ar / S_PLSS_Ln (Range, Township, Section)  S_Pol_Ar / S_Pol_Ln (Corporate Limits)  S_Trnsport_Ln (Transportation – roads, railroads, airports)  S_Wtr_Ln / S_Wtr_Ar (Hydro features)  S_Quad_Index (USGS Quads)  S_Base_Index (DOQs or other imagery)

Flood Map Modernization Lifecycle of a DFIRM Project  Survey and Topographic Data Structures and channel cross sections LIDAR Delivered to FEMA in data capture standards database (essentially a geodatabase)

Flood Map Modernization Lifecycle of a DFIRM Project

Flood Map Modernization Lifecycle of a DFIRM Project  Hydrology Prediction of flows in different rainfall events Many methods to calculate flows Use GIS to calculate parameters for model Uses watershed boundaries, landuse and soils Flows are used in Hydraulic Model  100yr event = 100cfs

Flood Map Modernization Lifecycle of a DFIRM Project  Hydraulics Determines water surface elevations at each cross section Elevations used to mapped floodplain on topographic data Detailed studies, limited detailed studies and approximate studies Typically utilize HEC-GeoRAS Cross Section View in HEC-RAS

Flood Map Modernization Lifecycle of a DFIRM Project  Mapping the Floodplain Partially automated with GIS Ground surface TIN – Water Surface TIN = Flood Depth GRID Conversion of all profiles and BFEs from NGVD 29 to NAVD 88 Datum Map 1% (100yr) and 0.2% (500yr) chance flood Determine Floodway, if applicable

Flood Map Modernization Flood Depth GRID

Flood Map Modernization Work Map

Flood Map Modernization Lifecycle of a DFIRM Project Draft work map for Buffalo River FIS

Flood Map Modernization GIS Uses in Flood Study Hydrologic Parameters HEC-RAS Geometry Automated Floodplain Delineation

Flood Map Modernization Lifecycle of a DFIRM Project  DFIRM Database Stores all GIS data to produce map panels Explained in Appendix L of FEMA specs Must adhere to FEMA guidelines and specs Undergoes extensive QA/QC

Flood Map Modernization Lifecycle of a DFIRM Project FEMA DFIRM Tools – Digitizing Flood Hazard Data from Effective FIRM panels

Flood Map Modernization Lifecycle of a DFIRM Project  Map Production (DFIRM Panels) Must adhere to Appendix K guidelines and specs Undergoes extensive QA/QC

Flood Map Modernization How do you use a DFIRM?  Paper maps are still printed  PDFs of maps  DFIRM database (GIS digital data)  FEMA Map Service Center (  FEMA Mapping Information Platform ( )

Flood Map Modernization Barnes County, ND DFIRM  FIS Report Engineers Report FIS Profiles Floodway Data Table Barnes County, ND FIS Profile Sheet

Flood Map Modernization Barnes County, ND DFIRM  DFIRM Database and GIS Data

Flood Map Modernization Barnes County, ND DFIRM

Flood Map Modernization Barnes County, ND DFIRM  DFIRM Panels

Flood Map Modernization Questions? Thank you for Attending! Julie Prescott, ND Map Modernization Coordinator North Dakota State Water Commission And Brian Fischer, CFM, GIS Project Manager Houston Engineering, Inc. FLOOD MAP MODERNIZATION