Interagency Flood Risk Management

Collaborating Nationally. Empowering Locally.

Flooding remains the leading cause of natural-disaster loss across the United States. The Interagency Flood Risk Management (InFRM) team brings together Federal Partners with mission areas of hazard mitigation, emergency management, floodplain management, natural resources management or conservation to leverage the skillsets, resources and programs to determine the needs of communities and define solutions and implement measures to reduce long term flood risk throughout the States of Arkansas, Louisiana, New Mexico, Oklahoma and Texas.

In 2014, the Federal Emergency Management Agency (FEMA) began sponsorship of the InFRM team initiative to allow Federal teams across the States of Texas, Oklahoma, New Mexico, Louisiana and Arkansas to better align and integrate. Currently, the InFRM team is comprised of FEMA, US Army Corps of Engineers, US Geological Survey, and the National Weather Service. No single agency has all the answers, but through a coordinated effort of multiple programs and various perspectives, a cohesive solution can be found. By applying their shared knowledge, the InFRM team can also enhance response and recovery efforts when flood events do occur.

While floods are impossible to prevent completely, and there is no way to guarantee protection of property, loss of life can be greatly reduced when communities have access to good data, practice sound land use, floodplain management and development practices and incorporate warning systems. Local communities can partner with the InFRM team to investigate solutions to reduce their communities flood risk.

Partner Agencies

This effort will be accomplished by an interagency coalition comprised of the Federal Emergency Management Agency, U.S. Army Corps of Engineers, U.S. Geological Survey, and the National Weather Service. These agencies are currently in partnership through the group known as the Interagency Flood Risk Management (InFRM) team and this effort will be undertaken by this group. The InFRM team will reach out to state and local government organizations as well as private industry to aid in moving this monumental effort forward.

  • Standards
  • Disaster/rebuilding aid through the flood insurance program
  • Mappings products
  • 2013 USACE CWMS watershed model development
  • Numerous watershed and planning studies
  • Watershed regulation
  • Stream gage program
  • Collect and disseminate reliable, timely data
  • Impartial, unbiased science
  • Precipitation estimates
  • Real-time forecasting and precipitation products
  • River forecasting

Integrated Water Resources Science and Services (IWRSS)

InFRM operates under the umbrella of the Integrated Water Resources Science and Services (IWRSS), a business model for interagency collaboration. IWRSS brings a consortium of United States federal agencies with complementary water resources missions together to share resources to help solve the nation's water resources issues. In 2011 several Federal agencies came together and initiated an Interagency Memorandum of Understanding to create IWRSS. IWRSS's overarching objective is to enable and demonstrate a broad, integrative national water resources information system to serve as a reliable and authoritative means for adaptive water-related planning, preparedness and response activities. The goals are to:

  • integrate information delivery and simplify access to this data
  • increase accuracy and timeliness of water information
  • provide summit-to-the-sea high resolution water resources information and forecasts

The members of IWRSS are the same four United States federal agencies as InFRM: USACE, USGS, NOAA, and FEMA.

Supercells in central Texas, April 26, 2015. Photo courtesy of Brian Khoury under creative commons license.

Estimate Your Base Flood Elevation

Base Level Engineering is a watershed-wide engineering modeling method that leverages high resolution ground elevation, automated model building techniques, and manual model review to prepare broad and accurate flood risk information for FEMA to assess its current flood hazard inventory. Base Level Engineering prepares flood risk information with scalable engineering, allowing FEMA to both assess its current flood hazard inventory and expand the coverage and availability of flood risk information to communities and individuals interested in reviewing their potential flood risk.

Goal: Centralized and available flood hazard analysis to support floodplain management activities and development review, while increasing risk awareness for individuals.


  • The Estimated Base Flood Elevation Viewer allows users to determine the flood risk (High, Moderate, Low) throughout watersheds that have been assessed using Base Level Engineering methods.
  • Estimated base flood elevations and flood depths for site specific locations (within the estimated 1% annual chance floodplain)
  • Immediate point-click-download access to engineering models and Base Level Engineering datasets.
  • Allows Federal, State, and local governments, as well as individuals, access to flood risk information.

FEMA is working with its Federal and State partners to identify watershed basins in need of flood risk information. Additional watersheds will be invested in each fiscal year, if your community is interested in having watersheds in your vicinity assessed, contact us to let us know of your interest.


  • Base Level Engineering is built on high resolution ground elevation information, allowing FEMA to prepare more accurate modeling.
  • Base Level Engineering hydrology is based on Regional Regression Equations. The results are reviewed against available gage records.
  • The hydraulic analysis leverages automated modeling techniques that are refined with manual manipulation to create a baseline engineering modeling.
  • Base Level Engineering allows development and engineering industry professionals to support local communities.

Base Level Engineering provides modeling and floodplain extents to assess these unknown and unverified mileage. Additionally, Base Level Engineering results have been prepared to meet all technical, engineering and mapping standards so that it may be used to update FIRMs in the case that the current inventory is not able to be validated.


Watershed-wide Base Level Engineering assessments develop the following flood risk information, available for download through this site:

  • Hydrologic calculations
  • Hydrologic spatial (GIS) files for sub-basins also available
  • Hydraulic (HEC-RAS) Modeling, prepared for 10%, 4%, 2%, 1%, 1%+, 1%-, and 0.2% annual chance events, input/output files
  • Hydraulic spatial (GIS) files – stream centerlines and cross-sections Flood Risk Results (GIS) to include:
    • 10%, 1%, and 0.2% floodplain delineations
    • estimated water surface elevation grids (1% and 0.2% annual chance event)
    • estimated flood depth grids (1% and 0.2% annual chance event)

Additional items may be available for download to include Hazus analysis (county or HUC8 level), Flood Risk Report, and/or Base Level Engineering Technical Report.

FEMA Region 6 is partnered with the InFRM team to work towards a future state where communities throughout the Region have a minimum dataset that describes the flood risk in their vicinity and allows them to determine a Base Flood Elevation. Base Level Engineering information does not replace the information shown on any current effective FIRM panel in a community, but may be used to identify areas a significant change in the floodplain delineation, water surface elevation or depth since the last flood risk study (both reduction and expansion) should be investigated with communities further.

FEMA will coordinate with local communities prior to initiating an update to the existing flood hazard information shown on FIRM panels across the nation.

The Estimated Base Flood Elevation Viewer

FEMA Factsheet

This factsheet summarizes what base level engineering is and how to use the new Estimated Base Flood Elevation Viewer, which is an interactive web portal that users can explore to review estimated flodd extents and possible flood depths.

What is Base Level Engineering?

FEMA Factsheet

This factsheet explains what the base level enginnering production approach is and how it can be used to reduce flood risk.

Contact Us

Arkansas John Bourdeau, Jr.
Whit E. Montague, CFM
Louisiana Shona Gibson
Cindy O'Neal, CFM
Susan Veillon
Oklahoma Alan Johnson
Yohanes Sugeng
New Mexico Jerry Clark
Wendy Blackwell, CFM (interim)
Shawn Penman
505.277.3622 ext. 227
Texas Larry Voice
Michael Segner, CFM
Manuel J. Razo, GISP, CFM
Estimated BFE Viewer Diane Howe


Flood Decision Support Toolbox

Goal: Develop the best available flood decision support toolbox for Texas and make it easily accessible to emergency managers and the public.

Benefits: Easily communicate to stakeholders what current and forecasted flood conditions are.


  • Inventory and evaluate engineering scale hydraulic models (HEC-RAS).
  • If model does not meet Integrated Water Resources Science and Services (IWRSS) standards update and recalibrate, if it does use existing model to generate flood inundation library.
  • If a high priority site does not have an engineering scale model, work with local agencies to develop model to generate and library.
  • Develop web application to get the toolbox out to public including current conditions, forecast conditions, and scenario analysis.

The Hydrologic Engineering Center’s (HEC) River Analysis System (RAS) will be the primary numerical modeling tool employed to prepare the inundation mapping products (U.S Army Corps of Engineers, 2016). HEC-RAS includes the capability for steady flow analysis, unsteady flow analysis and 2-dimensional modeling. HEC-RAS is the current standard for river hydraulic modeling across the United States. There is a vast array of existing HEC-RAS models available for various river systems across Texas. These models include:

  • FEMA effective models
  • USACE Corps Water Management System (CWMS) models
  • Models prepared with grants and other funding sources from the State of Texas
  • Models prepared for local governments

It will be necessary to utilize or develop geo-referenced models to ensure products can be leveraged by the Geographic Information Systems (GIS) community. Older non-geo-referenced products will be geo-referenced for utilization in this effort. If geo-referencing is not possible the models will not be utilized for this effort; however; cross-sectional data within these models, when it can be geo-referenced, will be utilized for model development.

The following is a high level listing of the steps that will be required for execution of this program:

  • Identification of river reaches for which the flood decision support toolbox would be of benefit to emergency responders and infrastructure management professionals.
  • Prioritization of the river reaches.
  • Identification of available river hydraulic numerical models which could be used to develop the flood decision support toolbox.
  • Identification of topographic data available for river reaches without hydraulic models.
  • Scoping the development of river hydraulic numerical models for reaches that do not have quality river hydraulic numerical models.
  • Calibration of river hydraulic models to field observation, when available.
  • Rating the quality of each product in the flood decision support toolbox for accuracy.
  • Using existing or newly developed hydraulic models to generate the flood decision support toolbox.
  • Development of best available flood decision support toolbox Statewide.
  • Development of web application to relay products to end users.


The InFRM team will collect, compile, evaluate, and when needed update existing models in order to provide the most informed flood decision support toolbox possible. The one foot increment flood maps will be peer reviewed and provided to emergency managers via web viewer, enabling them to make the most informed decisions possible.

A USGS hosted web-viewer will support the hosting, serving and downloading of the InFRM approved flood decision support toolbox. The USGS Texas Water Science Center will buildout a full development/production server environment to support the web-based framework. This will assure high-performance and flexible framework to handle enterprise hosting of the flood decision support toolbox into the system. As additional models become available the USGS will add them to the viewer as part of the operations and maintenance.

Hydraulic Model Database

InFRM Agency Model Status Summary (PDF)

Click on the image to see a larger view.

Hydrology Assessments

The primary objective of the InFRM Hydrology Assessments is to establish consistent and defendable flow frequency estimates for selected large river basins within FEMA Region 6. The hydrology assessments are being performed by a multi-agency scientific team of experts, with years of experience in local and regional hydrology, using a wide range of hydrologic methods. The hydrologic methods employed in these studies includes

  1. Statistical Hydrology,
  2. Rainfall-runoff modeling,
  3. Period of record simulations,
  4. Reservoir Studies and
  5. Stochastic Analysis.

The use and comparison of the results from multiple methods ensures the consideration of all available information that affects the hydrologic processes within the watershed.

InFRM hydrology assessments are currently underway for the following river basins: the Guadalupe, the Trinity and the Neches. These initial basins were selected based on watersheds where USACE already had sufficiently detailed modeling products available as a starting point for the assessments and where FEMA had future floodplain mapping activities scheduled.

The products of the hydrology assessments will include a final report which summarizes the full range of recommended frequency peak discharges for the 0.2%, 0.4%, 1%, 2%, 4%, 10%, 20% and 50% annual chance events. In urban areas, results may include both existing and future watershed conditions, if future land use data is available.

The results of the hydrology assessments will represent the best available estimate of flood risk across the entire river basin as prepared by a credible team of engineers and scientists from multiple federal agencies. The results of the hydrology assessments can be leveraged to support any future floodplain mapping activities within the basin along with any future planning studies authorized by Congress.


Interagency Flood Risk Management (InFRM) Hydrology Report for the San Marcos River Basin

USACE report

This report summarizes new analyses that were completed to estimate the 1% annual chance (100-yr) flow, along with other frequency flows, for various stream reaches in the San Marcos River Basin. These analyses are part of a larger study being conducted for FEMA Region VI by an Interagency Flood Risk Management (InFRM) team...


Ongoing Hydrologic Basin Studies shaded purple. Completed studies shown in green.

Atlas 14 Program

On September 27 of 2018, NOAA’s Hydrometeorological Design Studies Center released a new study called Atlas 14 Volume 11: Precipitation Frequency for Texas. The updated precipitation estimates supersede those currently available for Texas from the 1960s and 1970s. Atlas 14 data help state and local communities prepare for potential flooding and minimize weather's impacts on lives and livelihoods. Precipitation frequency estimates are used by engineers and planners to bring knowledge of flood hazards into land use and development decisions, including managing and designing stormwater infrastructure. Estimates are also used in hydrologic models to delineate flood risks and manage development in floodplains for FEMA’s National Flood Insurance Program. The InFRM team, led by USACE Fort Worth District, helped raise funds and manage this project to see that Texas has the same updated precipitation data as the majority of the nation. The new NOAA Atlas 14 estimates represent vastly improved data in terms of both period of record and station density, state of the art statistical techniques, and a new approach to spatial interpolation that accounts for variation in terrain.

Costs: The approximate cost for the Texas project is $1.5 Million.

Final product: At the end of the three year time frame (2015-2018), NOAA will provide:

  • Web based Precipitation Frequency Data Server for accessing geospatial data
  • Precipitation frequency estimates with upper and lower 90% confidence intervals at durations of 5, 15, 30, 60, and 120 minutes, 3, 6, 12, 24, and 48 hours, 4, 7, 10, 20, 30, 45, and 60 days, and ARIs of 1, 2, 5, 10, 25, 50, 100, 200, 500, and 1,000 years
  • High resolution grids of precipitation frequency estimates, provided in standard ASCII format accompanied by Federal Geographic Data Committee-compliant metadata.

Additional Resources

Corps Water Management System (CWMS)

Automated information system used by the U.S. Army Corps of Engineers (USACE) to support its water control management mission

Go to CWMS

Texas Water Dashboard

View over 750 USGS real-time stream, lake, reservoir, precipitation, and groundwater stations in context with current weather and hazard conditions.

Go to the dashboard

West Gulf River Forecast Center

View forecast locations experiencing flooding with links to detailed forecast information.

Go to the forecast center

FEMA Region VI

Oversees federal emergency management for the states of Arkansas, Louisiana, New Mexico, Oklahoma and Texas, and 68 federally recognized tribal nations.

Go to the FEMA site

Harvey Story Map

Scroll through a story map about Hurrican Harvey:
the costliest disaster in Texas history.

Go to the Story Map

NWS Advanced Hydrologic Prediction Service (AHPS)

See forecast tools that show the magnitude and uncertainty of occurrence of floods or droughts, from hours to days and months, in advance.

Go to AHPS

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