SJRA Board Takes No Action on Birch, Walnut Creek Dams Feasibility Study

3/27/26 – On 3/26/26, the San Jacinto River Authority (SJRA) board heard the results of a feasibility study about creating “dry-bottom dams” on Birch and Walnut Creeks. The creeks are far upstream in the Spring Creek watershed in Waller County and were being studied for flood-mitigation benefits.

The board made no decision in the meeting on whether to pursue recommendations from the study. However, they did agree to discuss several issues with study partners. Other sponsors included the City of Humble, Harris County Flood Control District and five municipal utility districts in Harris and Montgomery Counties.

Chief among the concerns discussed:

  • Whether funding is available given low Benefit-Cost Ratios (BCR)
  • Whether land is still available to build the projects
  • Finding a party that could take “ownership” the projects.

But before the presentation even started, Kaaren Cambio, a former director, laid down a fiery challenge to the board. Let’s look at the study first. It will provide a context for Cambio.

Benefit/Cost Ratio Concerns

Matt Barrett, PE, SJRA’s Water Resources and Flood Management Division Director, gave a presentation that summarized the results of the 661-page feasibility study.

The feasibility study came out of the larger San Jacinto Master Drainage Plan study which identified 16 projects costing approximately $3 billion in a 3000 square mile area upstream from Lake Houston.

  • Birch Creek had an estimated BCR of .55 to .83. That means costs exceeded benefits by almost as much as 2 to 1.
  • Walnut Creek had an estimated BCR of .77 to 1.04. In the best case scenario, benefits barely exceeded costs.
See estimated BCRs in blue boxes.

Only when you include “social benefits” do total benefits exceed costs. (See more on that below.)

Design and Operation

Barrett identified the construction as something akin to detention basins. The dams would feature a long barrier that trapped water with a small opening that let water out at a slow rate.

He next described how such construction would work in four different scenarios.

On a sunny day with no rain, water in the creeks would simply pass through them unobstructed.
In a small storm, not likely to cause flooding, water would still pass through the opening unobstructed.
But in a moderate storm that could cause minor flooding, water would pool behind the dam faster than it could go through.
In a major storm, water would also pass over the spillway at the top of the dam.

Barrett then talked about the exact locations of the dams, their widths, and land-use conflicts. The latter include a solar farm and new developments in the project footprints.

Benefits of Project(s)

Next, Barrett addressed the flood reduction benefits of the two dams in 10-, 50-, 100-, and 500-year storms.

He discussed the benefits of both dams together and individually. Below are the combined benefits of both dams.

They produce benefits measured in feet upstream and inches downstream.

Upstream, near the dams, the benefits exceed 3 to 4 feet. But downstream, near the confluence with the West Fork at the US59 bridge, benefits would only be 3 to 4 inches. That’s because the dams have a large effect on the small watersheds they directly control. But they exert no influence over the rest of the San Jacinto River Basin draining to that point.

Location of Structures Benefitted

The study found that more structures in Montgomery County Precinct 3 would benefit than anywhere else – by a factor of almost 4X compared to other jurisdictions.

Social Benefits Needed to Justify Funding

Near the end, Barrett showed what happens to the BCRs if you include “social benefits,” such as time lost from work during and after a flood. When you factor those in, the benefits exceed costs. However, Barrett also pointed out that as of 2025, the federal government no longer allows social benefits in BCR calculations.

Regardless, he says that the Texas Water Development Board still recognizes social benefits and that some funding could potentially come from them. But the cost of the dams would comprise a huge percentage of the state’s entire Flood Infrastructure Fund.

Significantly, while Barrett addressed the BCR, he did not call out total current costs. He did mention 2020 costs of $200 million in his narration. But total current estimates from the study put the cost at $298 million. And even $298 million assumes property can be acquired at market rates.

Conclusions

Barrett’s concluding slide focused on the challenges ahead based on the findings of his feasibility study. He implies the projects are still worthwhile if you consider social benefits. However, he acknowledges several additional hurdles ahead. And they are high hurdles.

For instance:

  • Who will take ownership of this project when the dams are in Waller County and the largest beneficiary is Montgomery County Precinct 3?
  • Where will the money come from when social benefits no longer apply?
  • Is the land available at any price?

For More Information

See Barrett’s full 38-minute presentation including the Q&A that followed, on the SJRA website. The video starts at 27:50 and runs to 1:05:18.

For a high-resolution PDF of Barrett’s complete slide deck, click here.

Cambio Comments

You may also want to watch Kaaren Cambio during the public comment period before Barrett took the floor. Cambio starts at 11:10 into the video. She is a former SJRA director appointed by Governor Abbott.

Cambio began by reminding the board that after Harvey, the governor charged the SJRA with developing short, medium, and long range plans to ensure another Harvey would never produce so much damage again.

She reminded them of the lake lowering plan and said “you have abandoned a proven solution with no substantive plan” because of a “lawsuit by a non-representative organization.” She lamented the:

  • Time it has taken the SJRA flood management division to produce studies
  • Management of the studies
  • Absence of any benefits produced to date in any of the SJRA studies since Harvey
  • Pursuit of the Spring Creek study even after it became clear the land was not available
  • Cost per structure pulled out of the floodplain in the Spring Creek study – more than $800,000 each
  • SJRA’s inability to examine less expensive options, such as buyouts or elevation of those structures

Cambio closed her remarks by urging the board to “Please go back and look at the goals that this division had and make sure you’re meeting those goals. And redirect your efforts, so that we are seeing manageable solutions.”

An outspoken leader, Cambio raised some great points.

You could sense the urgency in her voice as she pled with the board to implement solutions, not just studies.

Plea for Involvement

More people from downstream areas need to testify at SJRA board meetings. We should never let the SJRA board – now dominated by Lake Conroe residents – forget the destruction of lives and property caused by their massive release during Hurricane Harvey.

Posted by Bob Rehak on 3/27/26

3132 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.