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
  • Water quantity and quality monitoring and dissemination of reliable, timely data
  • Statistical analyses, modeling, and web application development
  • 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.

Benefits:

  • 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.

Methods:

  • 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.

Products

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.
John.Bourdeaujr@fema.dhs.gov
940.383.7350
Whit E. Montague, CFM
Whitney.Montague@arkansas.gov
501.682.1853
 
Louisiana Shona Gibson
Shona.Gibson@fema.dhs.gov
940.383.7326
Cindy O'Neal, CFM
cindy.oneal@la.gov
225.379.3005
Susan Veillon
Susan.Veillon@la.gov
225.379.3017
Oklahoma Alan Johnson
Alan.Johnson@fema.dhs.gov
940.383.7338
Yohanes Sugeng
yohanes.sugeng@owrb.ok.gov
405.530.8867
Aaron Milligan, CFM, RPES
Aaron.Milligan@owrb.ok.gov
405.530.8800
New Mexico Jerry Clark
Jerry.Clark@fema.dhs.gov
940.898.5270
Matt Lepinski
matthew.lepinski@fema.dhs.gov
940.297.0235
Veronica Chavez, CFM
Veronicae.Chavez@state.nm.us
505.476.9630
Texas Larry Voice
Larry.Voice@fema.dhs.gov
940.898.5419
Michael Segner, CFM
michael.segner@twdb.texas.gov
512.463.3509
Manuel J. Razo, GISP, CFM
manuel.razo@twdb.texas.gov
512.475.1850
Estimated BFE Viewer Diane Howe
Diane.Howe@fema.dhs.gov
940.898.5171

Flood Decision Support Toolbox

The InFRM Flood Decision Support Toolbox (FDST) is an interactive web application (WebApp) which:

  • visualizes current flood-related weather conditions in FEMA region 6 (Arkansas, Louisiana, New Mexico, Oklahoma, Texas),
  • allows peace-time analysis by emergency planners, local governments, and other stakeholders preparing for potential response activities (such as planned evacuation routes, identification of vulnerable areas requiring road closure, and resource planning in advance of flood events),
  • leverages federal, state, regional and local engineering model information to develop pre-positioned flood inundation libraries for micro-level efforts (neighborhood level),
  • connects National Water Model predictions for macro-level planning (community, county, state level),
  • uses pre-positioned map libraries to illustrate areas of potential flood inundation areas in relation to a field reported streamgage height,
  • can be expanded by data submittals by other Federal/State agencies, river management authorities, and other stakeholders,
  • and will be limited to the extent and availability of streamgage locations across the region.

Flood inundation map libraries at USGS streamgaging stations and NWS Advanced Hydraulic Prediction Service (AHPS) forecast points will be built using existing engineering-scale or FEMA base level engineering-scale specifications. For more information on AHPS forecasts, please see: https://water.weather.gov/ahps/about/about.php. The Hydrologic Engineering Center’s (HEC) River Analysis System (RAS) will be the primary numerical modeling tool employed to prepare the inundation mapping products (https://www.hec.usace.army.mil/). 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

Additionally, the FDST will incorporate NWS river forecast models that estimate the quantity and timing of water flowing through selected stream reaches in the United States during flooding events. These forecast models:

  • estimate the amount of runoff generated by precipitation and snowmelt,
  • simulate the movement of floodwater as it proceeds downstream, and
  • predict the flow and stage (water-surface elevation) for the stream at a given location (AHPS forecast point) throughout the forecast period (every 6 hours and 3 to 5 days out in many locations).
diagram of the FDST steps

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 map libraries for the FDST.

Documentation

Potential mapping partners may download the FDST Map Submission Guidelines to determine the modeling requirements and steps needed to generate map libraries for their area of interest. The FDST is a ‘living’ viewer that will be continually updated with new models and improvement to the interface. As such, the mapping guidelines will also be a ‘living’ document that will be updated with each update to the web application. Please continue to check the website for the most recent version of the guidelines.

InFRM Flood Decision Support Toolbox Executive Summary and Submittal Guidance

InFRM Report

Digital geospatial flood inundation mapping can be a powerful tool for flood risk management. Flood preparedness, communication, warning, response and mitigation can be enhanced by flood inundation mapping that shows floodwater extent and depth over the land surface...

Watershed Hydrology Assessments

As hydrology remains the single largest source of uncertainty in our understanding of flood risk, the InFRM team has been performing Watershed Hydrology Assessments to update flood risk estimates in large, complex river basins using suites of models developed by USACE.

The InFRM Watershed Hydrology Assessments (WHAs) are performed by an expert team of engineers and scientists from multiple federal agencies using the latest advances in hydrologic science and technology. The watershed assessments examine the hydrology across the entire basin, reviewing non-stationary influences, such as regulation, land use changes, and wet/dry climate variation, to ensure all variables affecting flood risk in the watersheds are considered. The multi-layered analysis employs a range of hydrologic methods, including rainfall runoff modeling, statistical hydrology, and reservoir simulations, and then compares the results of those methods to one another.

The goal of the watershed hydrology assessments is to produce consistent 1% annual chance (100-yr) and other frequency flows across the river basin, based on all available hydrologic information. The results of the hydrology assessments represent the best available estimate of flood risk across the entire river basin and provide suggestions for areas where the current flood hazard information may need to be updated.

River basins within the region are selected for hydrology assessments 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.

InFRM watershed hydrology assessments are currently underway for the following river basins:

  • the Guadalupe,
  • the Trinity,
  • the Neches, and
  • the lower Colorado River basins in Texas, and
  • the Little River basin in Oklahoma.

Additional basins will be added to the program as funding allows.

Publications

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

InFRM 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...

Interagency Flood Risk Management (InFRM) Watershed Hydrology Assessment for the Guadalupe River Basin

InFRM report

This report summarizes new analyses that were completed as part of a study to estimate the 1% annual chance (100-yr) flow, along with other frequency flows, for various stream reaches in the Guadalupe River Basin...

The InFRM Watershed Hydrology Assessments

InFRM Factsheet

The InFRM Watershed Hydrology Assessments (WHAs) are performed by an expert team of engineers and scientists from multiple federal agencies using the latest advances in hydrologic science and technology...

Ongoing Hydrologic Basin Studies shaded green. Planned studies shown in yellow.

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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