Tag Archive for: San Jacinto River Basin

How Fragmented Governance Boosts Flood Risk

4/2/2026 – Across the U.S., fragmented governance increases flood risk by creating a patchwork quilt of local interests that makes regulation, compliance and enforcement difficult. 

One might think that our multi-level system of government – federal, state, county, city, improvement districts, etc. – creates defense in depth. In reality, each governmental entity plays by its own rules and is responsible to different groups of voters with different priorities and interests. 

The problem is especially visible in large metro regions that involve numerous cities and counties with upstream/downstream conflicts of interest. Watersheds fragment into jurisdictional silos.

People downstream may experience flooding issues decades before upstream residents. And those upstream residents have no incentive to increase their taxes to pay for downstream mitigation. 

Fragmented governance, therefore pits groups against each other as development spreads outward.

It also creates an accountability gap – “Not our job!”

And regulatory inconsistency (different rules for detention, rainfall and fill) make it almost impossible to measure the cumulative impact of hydrological changes throughout the watershed.

In any given river basin, we may all be part of the solution. But we don’t all feel the problem. At least, not yet.

Denver’s South Platte Basin

Fragmented governance in the Denver metro—especially in the South Platte River basin—has been a persistent, structural driver of flood risk. A patchwork of cities, counties, special districts, and state/federal agencies manage the basin. The result: coordination gaps that translate directly into flood risk.

Alliance for the Great Lakes produced a fascinating case study about Denver. The South Platte basin includes:

  • City and County of Denver
  • Upstream suburbs (Littleton, Englewood, Lakewood, Aurora)
  • Multiple counties (Denver, Arapahoe, Jefferson, Adams, Douglas)
  • Special districts like the Mile High Flood District (MHFD)

MHFD develops regional drainage criteria. However, it does not regulate land use; local governments do. As a result:

  • Different jurisdictions adopt different stormwater standards, detention requirements, and update cycles
  • Upstream communities can:
    • Allow higher impervious cover
    • Use less conservative rainfall assumptions
    • Provide insufficient detention
  • Flows arriving at Denver often stack on top of each other and higher in volume
  • Cumulative peak flows exceed what any one jurisdiction modeled
  • No entity is responsible for system-wide flood control.

Need for Basin-Wide Master Planning

According to the EPA, each jurisdiction optimizes locally, not basin-wide. Upstream cities capture the tax base from new development and export their runoff downstream. Meanwhile, downstream, Denver bears the flood risk and mitigation costs.

Denver has acknowledged the need for basin-wide master planning. But historically, many tributaries fell outside FEMA mapping and were handled locally. Imagine every city along a freeway each designing the freeway to meet its own needs. That’s the system in flood control.

Storm sewers, channels, and detention systems do not align across boundaries and have mismatched capacities.

Encroaching development has already narrowed the South Platte floodplain. But no single entity has tracked the loss of floodplain storage.

Furthermore, no one jurisdiction coordinates infrastructure development of bridges and highways where they intersect drainage. Undersized crossings create system-wide backwater effects. 

In addition, the South Platte is heavily regulated by upstream reservoirs, which the Army Corps operates. But urban stormwater systems are operated locally and not fully synchronized. Sound familiar?

If that’s not bad enough, funding is also fragmented, leading to competition for funds. So projects advance unevenly across the basin, according to the EPA.

Chicago’s 200+ Drainage Jurisdictions

In Chicago, suburban expansion has increased runoff, but regional drainage capacity has not kept pace.

The Chicago area has even more extreme jurisdictional fragmentation than Denver. Cook County and three surrounding counties have more than 200 municipalities, plus a variety of state and federal agencies all sharing responsibilities for parts of the drainage.

Historically, each county has had different design storms, release rates, and detention requirements. Previously developed areas have had trouble keeping pace with upstream expansion.

The Chicago Area Waterway System also has three main rivers: the Chicago, Des Plaines and Calumet rivers. No single authority controls basin-wide runoff timing, impervious cover, or development in flood-prone areas.

Fragmented Governance Defies Attempts to Unify It

In the Houston area, efforts to overcome similar problems have met with mixed success. 

In 2022, Harris County Commissioners Court reaffirmed the need for minimum drainage standards in the region. The program was started in 2020 by the Harris County Engineering Department. The idea: to get all municipalities and other counties that drain into Harris County to adopt the same minimum drainage standards.

But after several early successes, the program seems to have quietly dropped out of the headlines.

Likewise, the San Jacinto Region 6 Flood Planning Group proposed minimum floodplain management practices throughout the river basin in 2025. But it is strictly an advisory group.

State Representative Dennis Paul introduced bills in the last two legislatures that would have established a river-basin wide flood control district. But each time, the bills have failed to gain traction and died in committees.

Counties within the San Jacinto River Basin
Counties within the San Jacinto River Basin

Texas 2036 and the American Flood Coalition hosted an informative seminar on 2/17/26. It emphasized lessons learned from other states about the need for river-basin-wide flood control to help ensure flood resilience. 

Everyone seems to recognize the need. But no one seems to have the power to address fragmented governance.

In Texas, we even have a state agency charged with flood mitigation investing in the development of property in floodplains and floodways…and denying FOIA requests to keep the investment secret. That’s how entrenched the problem of fragmented governance has become.

To see how fragmented governance compounds other factors that contribute to flooding, see the Lessons Page of this website.

Posted by Bob Rehak on 4/2/2026

3138 Days since Hurricane Harvey

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.

San Jacinto River Basin Recommendations in State Flood Plan

The new Texas state flood plan contains approximately 4351 recommendations in 15 regions statewide. The spreadsheet runs 147 pages in 3-point type. An eagle would have trouble seeing this type!

Recommendations in the San Jacinto River Basin alone (Region 6) total 519. And they’re buried within the larger spreadsheet, making it difficult summarize and compare them, much less see how the money is being distributed locally.

State Flood Plan Costs Staggering

The costs of the state flood plan are staggering. If all projects were implemented statewide tomorrow, they would cost more than $54 billion in 2024 dollars. Those in the San Jacinto Basin would total almost $10 billion.

Three Categories of Recommendations

Recommendations fall into three categories: Evaluations (engineering studies that lay the groundwork for future construction projects); Flood-Mitigation Projects (construction); and Strategies (buyouts, elevations, etc.)

The table below shows the breakdown. Region 6 (the San Jacinto Watershed) contains a lower percentage of flood mitigation projects and higher percentages of Evaluations and Strategies than the rest of the state, which is broken down into 15 regions.

Compiled from Volume II of Texas Flood Plan

The map below shows the different regions. Most contain one major river basin.

Texas flood planning regions
From Executive Summary of Flood Plan
From San Jacinto River Authority. The plan identifies many projects by watershed location. Use for reference.

These three PDFs contain Region 6 projects extracted from the 147-page Volume II of the state flood plan.

High Level Observations

Evaluations

I’m still analyzing all these entries. But already several things have jumped out at me from the standpoint of a Lake Houston Area resident.

Most of our stormwater comes from Montgomery County. But in the Evaluation list, Harris County projects outnumber those in Montgomery County by more than 5 to 1.

And most of the projects in Montgomery County tend to be limited in scope. For instance, Conroe has entries for a downtown master drainage plan, an Avenue M drainage plan, a South 3rd drainage plan and more.

Conroe also broke out separate projects for developing benefit-cost analyses associated with such projects and subdivision drainage projects.

Harris County and Galveston County, on the other hand, tended to look at things from a watershed-wide point of view.

Projects

The state flood plan lists only 69 flood-mitigation construction projects in all of the San Jacinto River Basin. And of those, only eight are upstream of Lake Houston. One is already a non-starter. The land for a detention basin on Spring Creek has already been sold for commercial development.

The remaining seven projects with their priority ranks include:

  • Caney Creek channel improvements and detention (#52)
  • Widening the West Fork and shaving down its flood plains (#67)
  • Peach Creek channel improvements and detention (#72)
  • Building a 1.6 mile earthen embankment to capture runoff from Winters Bayou in the East Fork watershed far upstream in San Jacinto County (#82).
  • Lake Creek Detention in Montgomery County (#105)
  • Improvements to the Kingwood Diversion Ditch (#144)
  • Cypress Creek detention (#149)
Strategies

It’s hard to see how any of the 654 strategies listed for the San Jacinto Basin would help the Lake Houston Area. Some might keep flooding from getting worse.

For instance:

  • Coastal Prairie Conservancy proposed a project to conserve more than 1,000 acres in the headwaters of Cypress Creek.
  • Harris County Flood Control proposed money for buyouts and relocations.

Missing: SJRA, Payment Plan, Integration

Strangely, the 147 pages of 3 point type in the state flood plan make no reference to the San Jacinto River Authority or SJRA.

Yet, as we saw in Harvey and again last May, the SJRA has huge gaps in its monitoring network upstream from Lake Conroe. During floods, these gaps make it difficult to assess how much water is moving toward the dam.

So dam operators tend to err on the side of caution and release more water than they may need to. In May, this contributed to the flooding of hundreds of structures downstream from the dam. To me, more gages would have been an important addition to the list.

It’s also not clear how Texas will pay for all these projects.

Currently, the flood infrastructure fund dashboard is down. So there’s no telling what the fund balance is.

But let’s assume it’s a billion dollars. If the legislature voted that every other year, it would take at least a century to build all these projects with inflation factored in.

Finally, it’s not clear how all these projects work together to reduce flood risk, though many mention that they should only be considered after other projects.

Hey, it ain’t perfect. But you have to start somewhere!

For More Information

To learn more about the first Texas state flood plan, read this executive summary, or a summary of the summary which I published earlier this year.

For a deeper dive into floodwaters, check out this Texas Water Development Board page.

Posted by Bob Rehak on 9/15/24

2574 Days since Hurricane Harvey

Top of SJR Basin Has Received Normal YTD Rainfall Plus a Harvey or Two

6/4/24 – Rainfall in the upper part of the San Jacinto River (SJR) Basin during early May storms rivaled Hurricane Harvey totals there. And if you consider year-to-date rainfall (YTD) totals, the amount above normal equals two Harveys in places!

The comparisons with Harvey help put into perspective some extraordinary rainfall in a relatively small geographic area that affects a much larger area.

The comparisons help explain why many people in the Lake Houston Area felt the May flood was far out of proportion to the amount of rainfall received. The most extreme rains did not fall on downstream residents’ heads. For downstream residents, the rains fell unseen – 50 miles north.

Let’s look at data for Huntsville first. Even though the City itself technically sits just outside the San Jacinto River Basin, rainfall south and west of the City entered both the East and West Forks of the San Jacinto.

Harvey Week vs Week Around May Storm

During Hurricane Harvey week in 2017, the SJRA gage southwest of Huntsville received 20.46 inches of rain.

Area near Huntsville received 20.46 inches during Harvey week in 2017.

During the late April/early May storm of 2024, the same gage received just a little less – 18.4 inches.

Huntsville total for week starting April 28, 2024, fell about two inches short of Harvey.

This area got almost as much rain in one week this May as it did during Harvey. Now let’s look at year to date numbers.

Year-to-Date Totals Vs. Harvey

The National Weather Service maintains another gage in Huntsville which accounts for a slightly different total. But I’m using it for the YTD comparison because of the powerful graph. It illustrates how much rain the area recently received compared to normal. (We already know the Harvey total from the first bar graph above.)

How wet has 2024 been? YTD accumulation graph.
From National Weather Service Climate Page.

From the brown line above, we can see that area normally gets 20 inches of rain through the end of May. This year it got 58.97 inches, almost triple the annual average at that point in the year.

The amount above normal (38.97 inches) is almost twice what the Huntsville area received during Harvey (20.46 inches)!

National Weather Service Data

So far this year, the upper river basin has received almost three Harveys worth of rain, or two above the normal YTD rainfall…for that latitude.

I should note here, that inland areas usually receive less rain than coastal areas during hurricanes. So if you’re saying, “Wait a minute! We received more than 20 inches of rain during Harvey,” you’re right. You also probably live south of Huntsville.

How to Compare Totals at Other Gages

Want to see what happened at a gage near you? HCFCD’s Flood Warning System lets you enter any date range using the historical feature. Just click on the “More Info” button associated with any gage. Or do it for the whole river basin to see the distribution of totals.

YTD rainfall distribution across upper SJR basin.

To quickly compare the distribution during Harvey, just change the dates to 8/25/17 and 8/29/17. It’s fun to explore. And it makes a fun learning experience for your kids. Teach them how to become “data detectives.” It could turn them into homeroom heroes.

Alternatively, you can compare Harris County gages during Harvey by consulting the tables at the end of HCFCD’s final Harvey report. It contains peak rainfall totals for all the gages above for time periods ranging from five minutes to four days.

The Reports Page of this website contains similar reports on other storms under the Major Storms tab.

Significance and Recommendations

There’s a point to all this data. We can draw several conclusions and recommendations from it:

  • Extreme rainfall in the northern tier of the river basin contributed to the flooding that many experienced 50 miles south.
  • Rainfall coming from the west and east was less intense and likely accounted for less damage downstream.
  • Heavy rains can fall outside of hurricane season. In fact, spring storms can exceed hurricane rainfall totals and rival hurricane intensity.
  • We need regional flood control. The people near Huntsville were not prepared for this event. Neither were people to the south protected.
  • Hurricane Harvey wasn’t a once-in-a-1,000 year rainfall. Pretending it was will jeopardize public safety. We need better building codes and drainage regulations in areas that haven’t already been updated since Harvey.
  • We also need updated flood maps that show current risk to help protect homebuyers. New floodplain surveys were conducted after Hurricane Harvey. But FEMA hasn’t yet released new risk maps based on those surveys. Many fast-growing areas in the region still base development decisions on data from the 1980s. That puts homebuyers at risk.

Flood Risk: A Shifting Target

Even as FEMA finalizes new flood-risk maps, understand that Mother Nature, sand mines, and insufficiently mitigated upstream developments are constantly changing the landscape through erosion and deposition.

The resulting blockages and reduction in conveyance may now contribute to increased flooding on smaller rains. Consider River Grove Park and the Kingwood Diversion Ditch. Both are now blocked by sand from upstream.

Kingwood Diversion Ditch at River Grove silted in again.
Kingwood Diversion Ditch where it passes through River Grove Park. Photo from 5/26.

It’s not as bad as it was after Harvey…yet. But up to five feet of sand was deposited in this area during the recent flood. So give it a few more floods.

As the City of Houston readies a $34 million dollar dredging program (that doesn’t even include River Grove), look what’s coming downstream to us.

Confluence of West Fork and Spring Creek near US59 bridge. West Fork, on right.

The West Fork snakes through 20 square miles of sand mines between US59 and I-45. And due to pit capture, the West Fork currently runs through a mile-long sand pit.

That raises one final recommendation: I wish the City could use its influence in Washington and Austin to have the EPA and TCEQ eliminate these blatant abuses.

In the meantime, the Kingwood Service Association will debate its own dredging program and the future of River Grove this Thursday night. To attend the online meeting, contact the KSA office at 281-358-5192 for a Zoom link.

Posted by Bob Rehak on June 4, 2024

2471 Days since Hurricane Harvey

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.

28 Watersheds, 11 Counties, $12 Billion in NFIP Claims, No One in Charge

The San Jacinto River Basin includes 28 watersheds and all or parts of 11 counties. We’ve experienced more than $12 billion in flood damages since 1975. And yet, incredibly, no one is in charge of drainage.

Map of San Jacinto River Basin and its watersheds, courtesy of SJRA.

According to the San Jacinto Regional Flood Planning Group, we also have 92 municipalities and 6.4 million people in the river basin.

We also have 1092 political subdivisions with flood-related authority. Yet no one is in charge of drainage.

We Work in Silos to Solve a Common Problem

That’s right. No one person is in charge of drainage. Instead, thousands of individuals working in their own little silos are scattered across more than 5,000 square miles. Unfortunately, stormwater doesn’t respect all those jurisdictional boundaries.

The San Jacinto Regional Flood Planning Group (reporting to the Texas Water Development Board) highlighted a “critical need for interagency coordination.” But there is none.

Screen capture from https://sanjacintofloodplanning.org

When No One is in Charge of Drainage, We All Suffer

Ironically, Texans won independence at the battle of San Jacinto. And we’ve been fighting to maintain it ever since.

We are so fiercely independent, we deny our interdependence. Even when it means destroying our own property and lives. It’s time to take a look in the mirror, folks.

Many ways exist to rank flood-prone areas and Texas ranks high on most of them.

And still, NO ONE is in charge of flood control.

Flood control is one area where Texans have room for improvement. But to improve we’ll need to work together.

Posted by Bob Rehak on 5/30/2024

2466 Days since Hurricane Harvey