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San Jacinto Flood Planning Group’s Proposed Minimum Floodplain Management Practices

11/11/25 – The San Jacinto Regional Flood Planning Group will consider adopting a set of proposed minimum floodplain management practices for the entire river basin at its meeting on November 13. The standards are part of a requirement by the Texas Water Development Board for the 2028 update of the state’s next flood plan.

The recommendations start on page 22 of the technical document. However, the document is 634 pages long and 214 megabytes in size. So, I’ve extracted them for easy reference.

They are targeted to floodplain managers in cities and counties in the San Jacinto River Basin. But they affect everyone from developers, homebuilders, and home buyers to home owners, insurers and first responders. So, I will add some explanatory comments below the proposed regs for those who may not understand their logic or language.

Proposed Minimum Floodplain Management Practices

Participation in the National Flood Insurance Program (NFIP)

All regulatory entities to implement ordinances that meet minimum requirements per the NFIP
All regulatory entities to remain active NFIP participants in good standing
All regulatory entities to participate in the Community Rating System (CRS) Program to reduce flood insurance rate premiums across the region.

Development of “No Adverse Impact” Policies

All regulatory entities to define a no adverse impact policy.
The no adverse impact policy should be focused on preventing negative impacts. Evaluation of impacts should be completed using best available hydrologic and hydraulic modeling, where appropriate.

Establish Minimum Finished Floor Elevations

All new habitable structures shall have a finished floor elevation established at or above or waterproofed to the FEMA effective 0.2% Annual Chance of Exceedance (ACE) flood elevation as shown on effective FIRMs except in areas designated as coastal flood zones.
Where regulatory mapping has been updated using Atlas 14 or newer rainfall data, all new habitable structures shall have a finished floor elevation established at or above or waterproofed to the FEMA effective 1.0% ACE flood elevation as shown on effective FIRMs except in areas designated as coastal flood zones.
In areas designated as coastal flood zones, all new habitable structures shall have a finished floor elevation established at or above or waterproofed to the FEMA effective 1.0% ACE flood elevation as shown on effective FIRMS plus 1 foot of freeboard.
All new critical facilities shall have a finished floor elevation established at or above or waterproofed to the FEMA effective 0.2% ACE flood elevation as shown on effective FIRMs plus 2 feet of freeboard except in areas designated as coastal flood zones.
Where regulatory mapping has been updated using Atlas 14 or newer rainfall data, all new critical facilities shall have a finished floor elevation established at or above or waterproofed to the FEMA effective 1.0% ACE flood elevation as shown on effective FIRMs plus 2 feet of freeboard except in areas designated as coastal flood zones.
In areas designated as coastal flood zones, all new critical facilities shall have a finished floor elevation established at or above or waterproofed to the FEMA effective 1.0%ACE flood elevation as shown on effective FIRMS plus 2 feet of freeboard.

Encourage Use of Best Available Data

Utilize the latest rainfall data, NOAA Atlas 14 or newer rainfall data, when conducting new analyses, designing drainage infrastructure, or developing regulations and criteria.

Compensatory Storage Requirements in the 1.0% ACE Floodplain

Any reduction in floodplain storage or conveyance capacity within the 1.0% ACE regulatory floodplain must be offset with a hydraulically equivalent (one-to-one) volume of mitigation sufficient to offset the reduction, except in areas identified as coastal flood zones.
A full hydrologic and hydraulic analysis should be performed to demonstrate that floodplain fill mitigation provided is sufficient.

Compensatory Storage Requirements in the 0.2/% ACE Floodplain

Any reduction in floodplain storage or conveyance capacity within the 0.2% ACE regulatory floodplain must be offset with a hydraulically equivalent (one-to-one) volume of mitigation sufficient to offset the reduction, except in areas identified as coastal flood zones.
A full hydrologic and hydraulic analysis should be performed to demonstrate that floodplain fill mitigation provided is sufficient.

Development of Detailed Hydrologic and Hydraulic Analysis Criteria/Requirements

All regulatory entities to develop hydrologic and hydraulic modeling criteria or requirements.
All regulatory entities to identify features of a proposed development that would warrant a full hydrologic and hydraulic analysis.

Incentivizing the Preservation of the Floodplain

All regulatory entities to explore and develop systems for incentivizing the preservation of the floodplain directly within the regulatory floodplain or within 100 feet of the banks of unstudied streams.

Nature-Based Solutions

All regulatory entities to adopt criteria for design of nature-based solutions for drainage infrastructure and stormwater quality management. TWDB’s nature-based solutions guidance manual should be referenced when adopting criteria.
All regulatory entities to establish criteria that would require new construction to incorporate, or minimally consider, nature-based solutions in design of drainage infrastructure and mitigation.

Operations and Maintenance

All flood-related authorities who own and operate drainage infrastructure to create a maintenance plan for those assets to manage and reduce future replacement costs.
All flood-related authorities who own and operate drainage infrastructure to develop and maintain an asset management plan, including GIS dataset of assets, to support maintenance of infrastructure. Datasets to leverage infrastructure toolkit that has been prepared by the TWDB to improve the assessment of drainage infrastructure condition and functionality.

Property Acquisition Program

All regulatory entities to develop property acquisition program for repetitive loss structures.

Flood Warning System

All regulatory entities to develop flood warning system for public awareness.

Hazard Mitigation Plan

All regulatory entities to develop a Hazard Mitigation Plan to help prepare for, respond to, and recover from flood events and maximize funding eligibility for disaster recovery funding.

Explaining the Proposed Minimum Floodplain Regulations

If you’re scratching your head about anything above, the following explanations may help.

NFIP and CRS

The National Flood Insurance Program’s Community Rating System (CRS) encourages counties and municipalities to go beyond minimum floodplain management requirements in exchange for discounts on flood insurance premiums for their residents.

CRS rewards local governments that implement regulations which:

Reduce flood losses
Encourage accurate insurance rating
Promote awareness of flood risk

Depending on the strength of a community’s practices, it could earn its residents anywhere from 0% to 45% discounts on their flood insurance premiums. Currently, Houston and Harris County earn 25% discounts. Montgomery County earns 15%.

So encourage your elected officials. This recommendation hits you in the pocketbook.

No Adverse Impact

Chapter 11.086 of the Texas Water Code says “No person may divert or impound the natural flow of surface waters in this state, or permit a diversion or impounding by him to continue, in a manner that damages the property of another by the overflow of the water diverted or impounded.”

The San Jacinto Flood Groups recommendation encourages local governments to adopt policies and best practices that prevent such adverse impacts.

Finished Floor Elevations

These recommendations encourage cities and counties to establish minimum heights above expected flood levels for buildings. “Finished floor” refers to living space. Sometimes people park cars under the first finished floor. This recommendation does not count garages below living space.

Together these recommendations say that if an area has adopted Atlas 14 (the latest rainfall probability statistics) and flood maps have been updated, the first finished floor can be set at or above the 100-year (1%) flood level. Otherwise, the first finished floor should be elevated at or above the 500-year (.02%) flood level.

Critical facilities, such as hospitals, fire stations, police stations and evacuation centers should always be at least 2 feet above the 500-year flood elevation.

Compensatory Storage Requirements

This recommendation is the same as “no net fill” requirements already in effect for many 100-year floodplains in the region. It has the effect of saying, “You can’t bring dirt into the floodplain, but you can move it around.” For instance, to elevate homes, builders would have to use the dirt excavated from a detention basin. It’s designed to prevent constriction of the floodplain, which could raise flood heights.

Hydrologic and Hydraulic (H&H) Analyses

H&H Studies define where and how flooding occurs, including how fast runoff occurs, how fast it will move and where it will go. They replace flood maps based on outdated or incomplete data. They incorporate Atlas 14 rainfall data and account for new development, impervious cover, and drainage changes, including recent channel improvements or detention basins.

They enable updated floodplain mapping and help build regional consistency in data and methodology. That in turn helps improve local floodplain regulations and insurance accuracy.

Floodplain Preservation and Nature-Based Solutions

The farther homes are from floodplains, the safer they are. Preventing flood damage is vastly cheaper than correcting damage afterwards, often by a factor of 5 to 10 times or more.

Floodplain preservation provides permanent benefits including economic continuity, insurance savings, environmental benefits, and recreational benefits. It also avoids post-flood recovery costs including infrastructure repair, housing assistance, insurance claims, business disruption, and environmental cleanup.

O&M, Property Acquisition, Flood-Warning System, and Hazard Mitigation Plan

The last four floodplain management recommendations emphasize preparation.

Regular maintenance, for instance, can keep channels from becoming clogged with sediment.
Buyouts in areas that flood repeatedly prevent future damage and mitigation costs.
Flood warning systems can tell people when to evacuate or streets to avoid in a flood.
A hazard mitigation plan helps identify natural hazards, assess risks and vulnerabilities, and outline long-term strategies to deal with them.

As common-sense as these ideas are, it’s amazing that many areas still have not adopted them. That may be why Texas has more people living in floodplains than the populations of 30 states.

Posted by Bob Rehak on 11/11/25

2996 Days since Hurricane Harvey

San Jacinto Regional Flood Planning Group Submits Final Recommendations

The San Jacinto Regional Flood Planning Group (SJRFPG) submitted its final recommendations to the Texas Water Development Board on January 10. The 316-page report includes recommendations on floodplain management evaluation, strategies and projects; the plan’s impacts; administration, regulatory and legislative recommendations; and financing.

I discussed the floodplain projects and impacts when I reviewed the draft plan in August of 2022. Not much as changed with the projects and impacts except for some minor details.

Now, with the state legislature in session, I would like to review the administrative, regulatory and legislative final recommendations in Chapter 8.

Legislative Recommendations

The SJRPG made four legislative recommendations to facilitate floodplain management plus flood mitigation planning and implementation.

Provide recurring biennial appropriations to the Flood Infrastructure Fund (FIF):

In 2019, the legislature appropriated money to establish the FIF. However, it did not appropriate additional funds in 2021. We need more money to fully implement the plans in the coming years.

Provide state incentives to establish dedicated drainage funding:

State law provides municipalities with the authority to establish local drainage utilities. Those that don’t use that authority generally rely on federal partners to fund floodplain management and regulatory programs. Or else they use some combination of general tax revenues and municipal bonds. The state should incentivize local communities to fund drainage projects rather than rely solely on federal funding.

Provide counties with legislative authority to establish drainage utilities/fees:

Municipalities have that power. But the unincorporated areas of counties do not. Give counties a reliable source of revenue to implement, maintain and repair drainage projects. Let them establish drainage utilities and drainage fees in unincorporated areas.

Update the state building code on a regular basis:

Texas is missing out on a billion dollars in FEMA’s Building Resilient Infrastructure and Communities (BRIC) Grants because of antiquated building costs. To take advantage of those grants, we need to update building codes. Adopt recent versions of the International Building Code (IBC) and the International Residential Code (IRC) at a minimum. Also we should adopt updated codes regularly in future legislative sessions.

Regulatory and Administrative Recommendations

The plan also made the following recommendations for regulatory and administrative changes.

Upgrade TxDOT design criteria:

Require all new and reconstructed state roadways to be elevated at or above the Atlas-14 1.0% annual chance flood level. Use the 0.2% level if Atlas 14 has not yet been adopted. TxDOT should also consider future conditions, such as urbanization and climate variability, in its roadway design criteria. TxDOT does not in all cases design roadways consistent with minimum NFIP requirements. TxDOT should strive to meet NFIP standards, especially for critical infrastructure such as evacuation and emergency routes.

Recommend Minimum Statewide Building Elevation Standards:

Recommend statewide minimum finished floor elevations at (or waterproofed to) the FEMA effective 2% annual chance flood except in areas designated as coastal flood zones. Use the 1.0% annual chance flood elevation where Atlas 14 has been adopted. Incentivize higher building standards. Recent historic floods and NOAA’s updated Atlas-14 rainfall probabilities reveal how much base flood elevations (BFE) can change over time. Jurisdictions that have required a freeboard over the current BFE have mitigated the risk of these increasing BFEs.

Clarify the process and cost to turn Base Level Engineering (BLE) data into Flood Insurance Rate Map (FIRM) panels:

BLE efficiently models and maps flood hazard data at community, county, watershed, and/or state levels. Currently, the state and FEMA are heavily investing in BLE. Clearly communicate to local jurisdictions how to implement this data in regulations and flood insurance rate maps. The steps remain unclear to many local jurisdictions.

Establish and fund a levee safety program similar to the TCEQ dam-safety program:

The TCEQ has a program to inspect dams that fall under its jurisdiction. Levees, on the other hand, are not subject to a similar safety program despite posing similar risks during flooding events.

Promote flood awareness, education, safety and outreach:

Partner with the Texas Floodplain Managers Association (TFMA) to promote public flood awareness, education, and safety in communities. Also, partner with Texas Association of Counties to do the same for Floodplain Administrators lacking technical flooding background (e.g., some County Judges). A well-informed public can make better informed personal choices regarding issues that involve flood risk and also will be more likely to support public policies and mitigation measures to reduce that risk.

Support ongoing education/training for floodplain management:

Provide no- or low-cost online resources including training modules, webinars, and print. Target training for non-technical Floodplain Administrators (e.g., County Judges who may serve as Floodplain Administrators but not have the necessary technical background). This would help to make effective floodplain management more prevalent across the state, especially in smaller counties.

Develop state incentives to participate in the National Flood Insurance Program (NFIP) and Community Rating System (CRS) program:

NFIP works with communities to adopt and enforce floodplain management regulations that help mitigate flooding. CRS encourages practices that exceed minimum requirements of the NFIP. Both programs are essential to achieving State Flood-Plan goals. Implement State-led incentives to encourage communities to participate.

Develop a public database that tracks flood fatalities:

Fatalities have occurred during extreme flood events throughout the state’s history. A statewide database and tracking system with appropriate privacy restrictions could aid in future project planning and regulatory decision making. It could also help with future education efforts regarding actions that frequently lead to fatalities. An example is the importance of not attempting to drive through flood waters.

Help smaller jurisdictions prepare grant and loan applications or make the process easier:

Provide training for Councils of Governments (COGs) to assist with the funding process. Developing applications for project funding can be difficult, especially for smaller jurisdictions with limited experience and access to funding to obtain expert assistance. Simplifying applications and making funding available specifically for application development would serve to make the process more accessible across the state and help close knowledge gaps.

Develop interactive models that use Base Level Engineering (BLE) data:

Provide them to Regional Flood Planning Groups and their technical consulting teams. Standardize future conditions and land use data. The State’s and FEMA’s BLE data should be available in most parts of the state.

Allow partnerships to provide regional flood-mitigation solutions:

Flood risk does not recognize jurisdictional boundaries, yet many flood-mitigation programs prevent multiple jurisdictions from working together if they want to remain eligible state funding. Flood-mitigation studies and solutions require inter-jurisdictional collaboration. Update policies to encourage and permit it.

Next Step on Final Recommendations

These final recommendations sound like good ideas to me. Please communicate your feelings to your state senator and representative.

I have summarized the final recommendations above. To see their exact text, review chapter 8. Or see the entire report to put them all in context.

Posted by Bob Rehak on 1/22/2023

1972 Days After Hurricane Harvey

New Resources from the San Jacinto Flood Planning Group

The San Jacinto Regional Flood Planning Group (SJRFPG) has greatly expanded its website and published a new interactive dashboard for the 11 counties drained by the river. Both represent valuable resources for anyone in the region concerned about flood mitigation.

If you missed the virtual meeting this evening on the Group’s Draft Flood Plan, here’s another chance to review it and give public input.

Expanded Website

The Flood Planning Group’s expanded website branched out from a modest home page originally designed to solicit input and allow people to sign up for a distribution list.

Clicking on the About page now takes you to a treasure trove of information about the region; the counties and cities in it; major lakes and reservoirs; the flood plan; members; and committees.

The Meetings page takes you to a calendar and an archive of meeting minutes, agenda, and videos.

Resources takes you to information from the Texas Water Development Board about the flood planning process.

You’ll find the DRAFT San Jacinto Regional Flood Plan under Technical documents. You’ll also find a web form to submit public comment like Nephew Izzy did. They will accept public comments until October 29, 2022. (Here’s a summary of the recommendations in Chapter 5 that I published shortly after the release in August.)

But the magic of the evening was a useful new dashboard for helping to understand flooding impacts in the world around us.

New Interactive Dashboard

The dashboard contains volumes of data in a graphic format synthesized from multiple geospatial resources. Want to know what’s happening where? Click on a county then an object. Pop up boxes describe each point. You can also see a graphic count of the total matching resources on the right hand side.

Turn different layers on and off to highlight certain types of information:

Regional boundaries
Flood infrastructure points, lines and polygons
Counties
Watersheds.

Select from 28 different basemaps that range from street maps to topographical maps and satellite images. And zoom from the 11-county region down to your house!

Clicking the tabs along the bottom pulls up different features of the dashboard.

Existing flood risk
Future flood risk
Existing mitigation
Flood risk reduction actions.

For instance, click on the future flood risk tab. Zoom into an area of interest, such as Forest Cove. See below.

*Future Flood Risk Tab of SJRFPG dashboard.*

Different types of information pop up this time. For instance, you can see the extent of floodplains in solid colors. You can also see:

Residential and commercial buildings at risk
Roadways at risk
Industrial buildings
Power generation
Public buildings
Bridges and more

If you want to know what’s at risk where you live, the San Jacinto Regional Flood Planning Group has given you a great way to compile an inventory.

More to Follow

There’s much more here than I can fit in a post. Explore. Open eyes. Amaze your friends and family.

Just one caution. The flood plains are not based on Atlas-14. They still use pre-Harvey data. The dashboard is a work in progress and will be updated when FEMA releases the new flood maps this winter.

Posted by Bob Rehak on 9/29/2022

1857 Days since Hurricane Harvey