Flood Mapping Resources
Flood Mapping Data Sources
Multiple sources for flood hazard mapping data are available. As a reference, the table below provides a quick overview of the characteristics (e.g., source, methods, and coverage) of commonly used flood mapping data sources (e.g., FEMA regulatory, Base Level Engineering (BLE), and Cursory Floodplain Dataset).
| Data Source/ Characteristics | FEMA Regulatory | BLE | Cursory | TWDB Quilt | Flood Planning Dataset |
|---|---|---|---|---|---|
| Maintained By | FEMA and CTPS | TWDB/FEMA, USGS (hosting) | TWDB | TWDB | RFPGs, TWDB (hosting) |
| Sources/Methods | Approximate and Detailed | Approximate | Approximate | Merge FEMA+BLE+Cursory | Merge variety of sources |
| Coverage | Selected Areas | Statewide | Statewide | Statewide | Statewide |
| Formats | Polygons | Polygons, Rasters | Rasters | Polygons | Polygons |
| Mapped Frequencies | 100-, 500-yr | 10-, 100-, 500-yr | 10-, 50-, 100-, 500-Yr | 10-yr, 100-yr, and 500-yr | 100-yr, 500-yr, |
| Inundation Areas | Yes | Yes | Yes | Yes | Yes |
| Flood Elevations | Yes | Yes | Yes | No | No |
| Model Availability | Partially | Yes | No | Source dependent | Source dependent |
| Min/Max Download Unit | Models - Reach/Watershed Mapping - Countywide | HUC-8 | 1-degree tiles / Statewide | Regionwide / Statewide | Regionwide / Statewide |
| Model Types | 1D, limited 2D | 1D, 2D (evolving to all 2D) | 2D | 1D, 2D | 1D, 2D |
| Update Frequency | Varies | 5 years | Undetermined | 5 years | Planning Cycle (typically 5 yrs) |
Flood Mapping Data Sources vs Uses
The table below provides an overview of generally appropriate use (e.g., Regulatory Mapping, Emergency Management, Science and Research, etc.) characterized as always, sometimes, rarely, or never for five common flood data sources (FEMA regulatory, Base Level Engineering (BLE), Cursory Floodplain Data, TWDB Quilt, and Flood Planning Dataset). The first column offers a broad use category while the second column offers more specific applications/uses. The terms provided in this table are somewhat subjective and there may be variations/exceptions to these classifications.
| Use Categories | Data Sources/Uses | FEMA Regulatory | BLE* | Cursory** | TWDB Quilt | Flood Planning Dataset |
|---|---|---|---|---|---|---|
| Regulatory Mapping | Updating FEMA Regulatory Maps (LOMR, PMR, FIRM) | Always | Sometimes | Never | Never | Never |
| Emergency Management | Preparedness | Always | Always | Sometimes | Rarely | Rarely |
| Flood Forecasting | Rarely | Sometimes | Rarely | Never | Never | |
| Flood Hindcasting | Sometimes | Always | Rarely | Never | Never | |
| Science and Research | Flood Science and Research | Sometimes | Always | Always | Sometimes | Sometimes |
| Planning | Flood Mitigation Planning | Always | Always | Sometimes | Sometimes | Always |
| Land Use Planning | Always | Always | Sometimes | Sometimes | Always | |
| Statewide Vulnerability Planning (TxDOT, other state agencies) | Sometimes | Sometimes | Always | Sometimes | Sometimes | |
| Infrastructure Design | Design Stormwater Infrastructure | Sometimes | Always | Sometimes | Never | Never |
| Permitting | Regulatory Permitting | Always | Sometimes | Sometimes | Rarely | Never |
| BFE Estimation | Always | Sometimes | Sometimes | Never | Never |
* Base Level Engineering (BLE) provides models, reports, and GIS data in addition to map data.
** The Cursory Floodplain Dataset provides statewide 2D coverage including pluvial/overland and coastal risk.
Mapping Data Sources
Below you will find links to federal and state mapping resources related to flooding and floodplain management.
Federal Mapping Data Sources
- FEMA's Base Flood Elevation Viewer
- This viewer provides information on BLE data availability, a map viewer to access flood inundation and elevations, and tools to download mapping products and the associated engineering model and analysis.
- National Flood Hazard Layer Viewer
- The National Flood Hazard Layer is a geospatial database that contains current effective flood hazard data.
- FEMA's Flood Map Changes Viewer
- The Flood Map Changes Viewer includes the following: preliminary National Flood Hazard Layer, preliminary Changes Since Last FIRM, the Preliminary Map Comparison Tool, and the pending National Flood Hazard Layer, and the National Flood Hazard Later.
- FEMA Map Service Center
- The FEMA Flood Map Service Center is the official public source for flood hazard information produced in support of the National Flood Insurance Program.
- FEMA Region VI Mitigation Awareness Portal
- The FEMA Region 6 Mitigation Awareness Portal shows the footprints of active Risk MAP Projects for all the five states (New Mexico, Oklahoma, Texas, Arkansas, and Louisiana) in Region 6.
- Guidelines and Standards for Flood Risk Analysis and Mapping Activities Under the Risk MAP Program
- These guidelines and standards define the implementation details of the statutory and regulatory requirements for National Flood Insurance Program mapping.
- Mapping Information Platform
- The MIP provides the latest tools and technology for digital flood map production to support the goals of FEMA and other mapping stakeholders.
- Risk Mapping, Assessment and Planning
- Risk MAP supports community resilience by providing data, building partnerships, and supporting long-term hazard mitigation planning. Access Risk Map products and additional information here.
State Mapping Data Sources
- TxGIO Data Hub (formerly TNRIS)
- The DataHub combines all TxGIO's Data Catalog, Data Download, Data Ordering, and Online Mapping Services into one easy-to-use online application.
- Interactive State Flood Plan Viewer
- This Interactive State Flood Plan Viewer complements Texas' inaugural 2024 State Flood Plan. The viewer allows stakeholders to view and download the extensive dataset generated by the statewide flood planning program, including flood risk and recommended flood risk reduction solutions.
- Hydrologic and Hydraulic (H&H) Model Method Catalog
- Texas A&M's Institute for a Disaster Resilient Texas (IDRT) Measuring, Mapping, and Managing Flood Risk (M3FR) Modeling Software Catalog includes commonly used flood hazard models. This catalog allows users to filter software by the following features: Type, Process (costal, fluvial, pluvial) Scale (site-scale/local, watershed, multi-watershed/regional, and continental), Phase, and NFIP-approved models.
- IDRT's Interactive Web Tools
- Texas A&M's IDRT developed a collection of interactive tools to share flood resilience related research. The series includes Buyers Aware, M3FR, Rebuild Texas, Coastal Bay Atlas, Cost/Benefit for Flood Reduction Mitigation Strategies, Texas Historic Insured Flood Loss Analysis, and Economic Impacts of Hurricane Storm Surge in Galveston Bay.