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.

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

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.

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.

  • 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

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.

DOCUMENTS

Estimated Base Flood Elevation Viewer Factsheet

Summarizes base level engineering and how to use the new Estimated Base Flood Elevation Viewer, which is an interactive web portal.

What is Base Level Engineering? Factsheet

Explains the base level engineering production approach and how it can be used to reduce flood risk.

Base Level Engineering Region 6 Submittal Guidance Document

Supports effective preparation of Base Level Engineering analysis, including compilation of the minimum deliverables and datasets.

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.

Contact Us

Arkansas Christy Weiser
Christy.Weiser@fema.dhs.gov
202.705.9624
Shawn Jackson
Shawn.Jackson@agriculture.arkansas.gov
501.682.3959
Whit E. Montague
Whitney.Montague@agriculture.arkansas.gov
501.682.3969
Louisiana Alan Johnson
Alan.Johnson@fema.dhs.gov
225.620.7062
Cindy O'Neal
cindy.oneal@la.gov
225.379.3005
Susan Veillon
Susan.Veillon@la.gov
225.379.3017
Oklahoma Tarah (Baumgartner) Graham
Tarah.Baumgartner@fema.dhs.gov
202.878.1697
Jon Phillips
Jon.Phillips@owrb.ok.gov
405.255.9145
Aaron Milligan
Aaron.Milligan@owrb.ok.gov
405.530.8800
New Mexico Brittany Brush
Brittany.Brush@fema.dhs.gov
202.285.8183
Loretta Hatch
Loretta.Hatch@state.nm.us
505.377.1616
Shawn Penman
spenman@edac.unm.edu
505.277.3622 x227
Texas Larry Voice
Larry.Voice@fema.dhs.gov
940.898.5419
Manuel J. Razo
manuel.razo@twdb.texas.gov
512.475.1850
Estimated BFE Viewer Diane Howe
Diane.Howe@fema.dhs.gov
940.435.9588

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.

PRODUCTS

FDST User Guide

How to use FDST for estimating flood extent and depth for possible flood scenarios based on the underlying models.

FDST Executive Summary and Submittal Guidance

Provide standardized guidelines, quality assurance checks, and data input format for submitting flood inundation data for inclusion on the FDST viewer.

InFRM FDST Geoprocessing Toolbox

Geoprocessing tools and scripts designed to streamline the workflow required to process map libraries for upload to the InFRM FDST.

FDST 2d Hydraulic Model Guidance

Determine the suitability, applicability, and subsetting of 2D FEMA BLE models for generating FDST libraries and guidance for extracting portions of 2D models for use in the FDST.

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. The Hydrologic Engineering Center’s (HEC) River Analysis System (RAS) will be the primary numerical modeling tool employed to prepare the inundation mapping products. 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. A vast array of existing HEC-RAS models are available for various river systems across Texas including

  • 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).

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.
diagram of the FDST steps

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.

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 (WHAs) to update flood risk estimates in large, complex river basins using suites of models developed by USACE.

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

The goal of the WHAs is to produce consistent 1% annual chance (100-yr) and other frequency flows across the river basin, based on all available hydrologic information. The final recommendations of the WHAs are formulated through a rigorous review process which includes technical investigations, external peer reviews, stakeholder input, and collaboration between all of the InFRM subject matter experts.

River basins within the region are selected for hydrology assessments based on watersheds where USACE already has sufficiently detailed modeling products available as a starting point for the assessments and where FEMA had future floodplain mapping activities scheduled.

InFRM WHAs have been completed for the following river basins in FEMA Region 6:

The final reports and appendices for these studies can be downloaded from the links to the right.

InFRM WHAs are currently underway for the following river basins:

  • the Lower Colorado River Basin in Texas,
  • the Nueces River Basin in Texas,
  • the White River Basin in Arkansas, and
  • the Brazos River Basin in Texas.

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

As a result of the level of investment, analyses, and collaboration that go into the WHAs, their results are recommended as the best available estimate of flood risk for the studied streams in the river basin, and they provide suggestions for areas where the current flood hazard information may need to be updated. The results from the WHAs can also be used to plan new infrastructure and safely locate new neighborhoods and other urban development. Furthermore, the models and data used to produce these flood risk estimates are available upon request, at no charge, to communities, local stakeholders, and architecture engineering firms.

For more information from any of these studies, please use the link below:

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
    • 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 USACE to support its water control management mission.

National Water Dashboard

See provisional real-time water data at USGS observation stations in context with current weather and hazard conditions.

West Gulf River Forecast Center

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

FEMA Region VI

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

Harvey Story Map

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

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.

Storm Shifting

See example study with informative, relatable, and non-regulatory data to better understand and mitigate flood risk.

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