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An Update on the TWDB’s Texas-Sized State and Regional Flood Planning Effort


An Update on the TWDB’s Texas-Sized State and Regional Flood Planning Effort

March 2023

Reem J. Zoun PE, CFM, ENV SP, M. ASCE
James Bronikowski PE, CFM
Tressa Olsen, MSCRP, CFM

In August 2022, ASCE Texas Section published an article about the statewide flood planning effort. This article updates the regional flood planning groups’ progress in developing their plans and lays out the next step in state flood plan development.

The first set of regional flood plans were delivered on schedule to the Texas Water Development Board on January 10, 2023, without much fanfare. However, a tremendous amount of behind-the-scenes effort went into this by the chairs, officers, and other members of the 15 regional flood planning groups, their sponsors and technical consultants, the public, and Texas Water Development Board (TWDB) staff.

It all started in the wake of Hurricane Harvey, when the 2019 Texas Legislature greatly expanded the TWDB’s role in flood mitigation and passed Senate Bill 8 (SB 8), which created the regional and state flood planning program. In addition to providing new funding mechanisms for flood mitigation projects (the Flood Infrastructure Fund and the Texas Infrastructure Resiliency Fund), the legislation mandated that the TWDB establish and administer a statewide flood planning process.

The TWDB is currently administering this new process with flood planning regions based on river basins. The initial regional flood planning groups were formed on October 1, 2020; the first regional flood plans were due in January 2023, and the first state flood plan will be due September 1, 2024. The regional flood planning groups were provided with additional funding to amend their regional plans in summer 2023 to increase the number of flood mitigation projects that can be included in the state flood plan.

The overarching goal of the regional and state flood plans is to protect against the loss of life and property from flood. The regional and state flood planning processes focus on both (a) reducing existing and future flood risks to life and property and (b) minimizing and avoiding increasing flood risk in the future by keeping people and property out of the way of flood flows. The 2023 Regional Flood Planning Program and the 2024 State Flood Plan are developed through a highly transparent process and not only represent the first statewide coordinated flood planning effort for Texas, but also in the U.S.. Key information about the statewide flood planning program can be found on the TWDB Flood Planning website, https://www.twdb.texas.gov/flood/planning/index.asp.

Figure 1: Regional and State Flood Planning Timeline
RFPG = regional flood planning group

Regional Flood Planning


  • 15 flood planning regions based on Texas’ major river basins
  • Each planning region has an associated planning group made up of volunteer voting members
  • Voting members must represent a minimum of 12 interest categories
  • Each group also maintains non-voting members from relevant state agencies: TWDB, Texas Commission on Environmental Quality, Department of Agriculture, General Land Office, Texas Division of Emergency Management, Texas State Soil and Water Conservation Board, and Texas Parks and Wildlife Department
  • Each flood planning group was responsible for developing its own regional flood plan in accordance with the state flood planning framework, with public input along the way
  • Planning group sponsors are provided grant funds to procure and direct technical consultants to develop the regional flood plans

Key Tasks

There are many tasks in the process, but the key flood planning tasks include the following:

  • Identifying areas of flood risk, including hazard, exposure, and vulnerability
  • Setting flood protection goals for the region
  • Identifying and recommending flood management evaluations, flood mitigation projects, and flood management strategies
  • Quantifying the comprehensive flood risk and the approximate cost for reduction for flood risk and impact in each region
  • Making legislative and regulatory recommendations


Figure 2: The Regional Flood Planning Groups

This regional flood planning process, as established by the legislature, can be described as a “bottom-up” approach with regional, watershed-based flood plans being compiled by regional stakeholders into a comprehensive statewide flood plan. Recognizing that the natural flow of water does not respect political or administrative boundaries, the TWDB divided the entire state into 15 flood planning regions based on major river basins. The planning effort within each flood planning region is developed and administered by self-governing bodies made up of local stakeholders representing a wide range of interest categories. Some members have technical flood experience and bring this perspective when representing their interest category, but many do not have such flood-related experience and are valued for their unique local perspective related to flood-related issues.

These self-governing bodies are known as regional flood planning groups (RFPGs), and they have grant funding to hire technical consultants and perform a detailed scope of work to develop forward-looking regional flood plans. The RFPGs provide a critical link in the flood planning process between those affected by flood events locally and regionally and the state flood plan. The groups are made up of volunteer members that live and/or work in areas across their respective flood planning regions and represent one of the diverse interest categories required by Senate Bill 8 and agency rule. These 12 required interest categories are agricultural interests, counties, electric generating utilities, environmental interests, flood districts, industries, municipalities, small business, public, river authorities, water districts, and water utilities. Each RFPG is required to include a voting member representing each interest category unless it determines a particular interest does not exist within the planning region. The TWDB, Texas Commission on Environmental Quality, General Land Office, Texas Parks and Wildlife Department, Texas Department of Agriculture, State Soil and Water Conservation Board, and Texas Division of Emergency Management are required to appoint representatives to serve as ex-officio non-voting members on each RFPG, and each of these state agencies coordinated to develop guidance principles for use throughout the regional and state flood planning processes.

Overall, the primary goals of the regional and state flood planning processes are for the RFPGs to evaluate existing and future flood risk within their flood planning regions for the purpose of increasing protection against the loss of life and property. More specifically, these processes require an evaluation of the hazard, exposure, and vulnerability components of flood risk for every part of the state to more accurately identify both existing and future flood risk while also identifying and recommending potential flood mitigation solutions to address these risks. It is in these tasks that RFPGs are in most need of assistance and participation from local stakeholders and floodplain management professionals. The people that have lived and worked through multiple flood events in their own areas often have the best understanding of their local flood issues, and this local participation is needed to help improve the accuracy of flood risk planning data and identify the complete picture of flood mitigation need. With so much emphasis on data gathering, it is important to note that these flood risk evaluation efforts are for the purposes of a planning level analysis for everyone to better understand their associated flood risk, and that neither the TWDB nor RFPGs have any regulatory authority. This watershed-focused approach to flood planning allows entire regions with a shared hydraulic connection to plan together and address their flood risk in a way that focuses on their unique needs. This approach also supports a statutory requirement for the TWDB and thus every RFPG to ensure that no aspect of any regional flood plan has a negative effect on any neighboring area. This includes neighboring areas both within and adjacent to each flood planning region. This holistic approach of regional planning to identify potential flood mitigation solutions while avoiding negative effects on neighboring areas should magnify the net benefits of Texas’ flood mitigation efforts. This approach should enhance available economies of scale by avoiding competing projects or inefficient, piecemeal development of flood mitigation that could cause an inefficient investment or even contradictory results.


  • January 2022 – Technical Memorandum 1
  • March 2022 – Technical Memorandum 2
  • August 2022 – Draft Regional Flood Plan + public comment period
  • January 2023 – Final Adopted Regional Flood Plan


Submission of the final Regional Flood Plans and Board Adoption

By January 10, 2023, all 15 RFPGs submitted their final regional flood plans to the TWDB. Following a brief review period, the plans will be presented to the TWDB Board for approval and adoption.

Amendment of Regional Flood Plans

In 2021, the TWDB allocated additional funds to the RFPGs to perform flood management evaluations in order to develop additional mitigation projects for inclusion in the state flood plan. Essentially these evaluations will identify and assess the feasibility of potential projects, including a determination of whether the project may impose negative effects on neighboring areas. The work performed by RFPGs between January 10 and July 10, 2023, will be the basis for the amended regional flood plans due July 10, 2023.

2024 State Flood Plan


The 2024 State Flood Plan will have the first- ever comprehensive look at the state’s flood risk and the magnitude of solutions needed to reduce the risk and impact of flooding in Texas primarily for a 1 percent annual chance storm event, also known as a 100-year flood.

The 86th Legislature’s SB 8 directs the TWDB to develop a state flood plan, which must provide for orderly preparation for and response to flood conditions to protect against the loss of life and property; be a guide to state and local flood control policy; and contribute to water development where possible. As part of this, the plan will include information about how many critical facilities, including hospitals, police stations, fire stations, and schools, are at risk of flooding.

The state flood plan will use information provided and data gathered from the 15 regional flood plans. The plans will provide information on areas of flood risk and recommended flood management solutions to address these flood risks. The recommended flood solutions will then be ranked in the state flood plan according to how well they address the worst flooding problems in the state. The state flood plan will also include a summary of flood planning contributions to water developments and legislative recommendations.

To supplement the written plans, the TWDB will also develop an online interactive viewer which will present state flood plan information geographically and serve as a user-friendly interface for the public, legislators, and other agencies. Users will be able to visualize existing and potential flood risk across the state as well as existing and potential flood solutions for their communities. We anticipate the Viewer becoming available to the public with the release of the state flood plan in fall 2024.

Figure 3: 1935 Flood, Downtown Austin, Texas.
Source: Austin History Center

Ranking of Projects

As stated in Texas Water Code § 16.061(b)(2), “The state flood plan must include: … a statewide, ranked list of ongoing and proposed flood control and mitigation projects and strategies necessary to protect against the loss of life and property from flooding…”

Identifying and recommending flood risk reduction projects in the regional flood plans, ranking recommended flood risk reduction projects in the state flood plan, and providing state financial assistance to implement specific projects are three separate processes that will occur at different times. The regional flood planning groups identify and recommend flood risk reduction projects and provide relevant data associated with each project as part of the regional process. The state flood plan will combine and summarize the regional plans and rank all recommended projects.

The TWDB will solicit stakeholder input on a proposed ranking process prior to developing the draft state flood plan. The final ranking process will take into consideration stakeholder input on the ranking criteria and associated weighting factors and will become part of the state flood plan.

To be considered for future flood mitigation funding administered by the TWDB, flood solutions must be in the state flood plan. Therefore, it is important that communities participate in the regional flood planning process to bring forth their studies and projects to formally become recommended projects in their regional flood plan.

Local sponsors generally implement flood risk reduction projects, either with local financing, federal funding, public-private partnership, or state financial assistance. The TWDB anticipates future state financial assistance for projects in the state flood plan in accordance with existing program requirements. While inclusion in the state flood plan is a requirement for future flood funding considerations, the funding process is separate from the planning process. The TWDB anticipates developing, for example, a separate Flood Intended Use Plan detailing the structure of each funding cycle, application requirements, and potential prioritization scoring.

Key Initiatives for Statewide Flood Planning


In addition to the work performed for both the regional and state flood planning programs, the TWDB and other state agencies are working on initiatives to support statewide flood planning efforts. As mentioned earlier, members from various state agencies serve on the RFPGs as non-voting members. In addition, several regional flood planning groups have added members from regional water planning groups, the U.S. Army Corps of Engineers, and the Texas Department of Transportation, amongst other entities. The TWDB regularly meets with various state, federal and education entities including FEMA, GLO, NWS, TAMU, TDEM, TWDB, TxDOT, USACE, USGS, and UT Austin to share program and project updates.

Data Sharing Agreement with the General Land Office (GLO)

This agreement was established to support open collaboration and interagency cooperation to support the GLO’s combined river basin flood studies and the TWDB’s regional flood plans. This agreement serves to maximize efficiency of study efforts through coordination of study tasks, leveraging data and products produced by each study, and will help expedite study schedules.

TWDB-TDIS Model Management System (MS2)

The TWDB worked with the Texas Disaster Information System (TDIS) to develop the MS2 Model Management System as a repository for flood models utilized in the development of the regional flood plans. The system allows the flood planning regions’ consultants to upload the models, which will eventually be available for download once the Interactive State Flood Plan Viewer becomes available in 2024.

Benefit-Cost Analysis Tool

The regional flood planning process requires inclusion of benefit-cost ratio for the flood mitigation projects. To allow several other benefits to be incorporated in addition to the traditional benefits, the TWDB funded and guided development of a user-friendly benefit-cost analysis input interface in the form of a spreadsheet document that works in conjunction with the FEMA Benefit-Cost Analysis Toolkit. These can be found here: Benefit-Cost Analysis (BCA) Input Tool and Instructions.

Floodplain Quilt

The floodplain quilt (Draft Floodplain Quilt) consists of multiple layers of data from various sources available throughout the state to “quilt” together a single flood hazard dataset. The Quilt is only the starting point of flood hazard data for the RFPGs. RFPGs will need to review and potentially re-prioritize the quilt data as appropriate by location and incorporate additional information available in their respective regions. The Draft Floodplain Quilt, floodplain quilt input viewer, and prioritization are being provided alongside the guidelines.

Flood Planning Data Hub

The Flood Planning Data Hub is the regional flood planning groups’ go-to source for information compiled by the TWDB. It includes resources from many entities. An index of GIS resources is available online: https://www.twdb.texas.gov/flood/planning/data.asp .

Geodatabase Template

The TWDB generated template GIS geodatabases with multiple feature classes and tables for the RFPGs to complete and submit with their regional flood plans. This enables the 15 RFPGs to submit consistent datasets that can be brought together as one state flood plan.

SVI Study

Social Vulnerability Indices (SVIs) are used for a variety of purposes, but they are neither customized for flood hazard nor for Texas. The TWDB is currently funding a study to develop a flood-specific SVI for Texas that considers and utilizes parameters applicable and relevant to flooding.

Cursory Floodplain

The TWDB worked with Fathom to develop the Cursory Floodplain dataset. This is a set of 3-meter resolution cursory floodplains. The dataset includes probability frequencies of 20 percent, 10 percent, 1 percent and 0.2 percent annual chance flood events (also known as 5-year, 10-year, 100-year, and 500-year flood events, respectively). This dataset is generally most useful where other flood hazard data is not available.

Future Condition Flood Hazard

As part of the first planning cycle, each of the regional flood planning groups identified and compiled a comprehensive outlook of future condition flood hazards in their respective regions based on guidance provide by the TWDB. The TWDB is currently looking into developing statewide cursory future condition flood hazard information to support the regional flood planning groups.

Infrastructure Assessment

The regional flood planning process asks each of the 15 flood planning regions to identify its flood infrastructure and the associated condition (functional vs non-functional; deficient vs. non-deficient). The TWDB is funding research to develop readily usable planning-level infrastructure condition assessment methods, including a toolkit for assessing the condition of flood infrastructure at a regional planning level for future planning cycles. This research will also look at infrastructure assessment indicators currently identified in the TWDB Flood Planning Program and recommend enhancements as applicable.

Other Research Studies

The TWDB is working on various research projects expected to support the future planning cycles, including a guide for the use of nature-based flood mitigation solutions and a model for calculating economic losses of crops and/or livestock from flood events. For more information, please visit  https://www.twdb.texas.gov/flood/science/research.asp#fy2020-2021.  

Next Steps

Once the 15 amended regional flood plans are submitted to the TWDB by July 10, 2023, they will be considered for approval by the TWDB and the information from those plans will be used to develop the state flood plan. Similar to the first cycle of regional flood planning, development of the first iteration state flood plan must meet the statutorily required delivery deadline of September 1, 2024. The regional and state flood planning processes will continue in five-year cycles thereafter.

Seeking Feedback

The TWDB has engaged in several processes to gather feedback from stakeholders, including regarding lessons learned from the first regional flood planning cycle. These included a flood planning group stakeholder feedback survey; meeting with technical consultants directly involved in developing the regional flood plans; and seeking general, preliminary input prior to embarking on our formal rulemaking process, amongst others. This feedback will improve the administrative and planning processes and create greater efficiency during the next planning cycle. The TWDB expects to seek public feedback on proposed rules governing flood planning process around May 2023.

How to Get Involved

As the collective regional and state flood planning process consists of a “bottom-up” structure, it is driven by local stakeholder input. If you represent a city, county, or entity with flood-related responsibilities, the RFPGs want to hear from you about your needs or plans for flood-related studies and projects. While the first cycle of regional flood planning will be coming to an end this summer, there will be many opportunities to take an active role in the second cycle of regional flood planning as early as fall 2023, including serving as a voting or non-voting member. Use the Regional Flood Planning Group Locator Tool to find the group responsible for regional flood planning in your area. You may also find more information on public meetings, opportunities for participation, and details on the flood planning process on the TWDB’s Flood Planning website.