SJRA says upstream detention dams could cut Spring Creek flood levels but need state/federal funding; Bear Branch spillway flagged for immediate work

SAN JACINTO BASIN, TEXAS — Engineers from the San Jacinto River Authority told The Woodlands Township Board on an August 2025 evening that proposed dry‑bottom detention dams on Birch and Walnut creeks could meaningfully reduce flood elevations for the township but will require large state or federal funding and an identified project sponsor.

The presentation, led by Matt Barrett, SJRA’s lead engineer, summarized a multi‑year feasibility study for the Spring Creek watershed. Barrett said model refinements allowed the team to reduce dam heights (about 5–7 feet in the optimized layouts) and thus shrink projected upstream inundation (roughly 200–300 acres less than earlier layouts). “If both dams were constructed, there’s about 1,000 structures that we project would benefit and have reduced flooding,” Barrett said, adding that “about a 100 or maybe a little more than a 100 that would no longer flood if Hurricane Harvey were to happen again.”

Why it matters: the modeling shows measurable reductions in peak creek elevations inside township boundaries — Barrett summarized reductions of roughly 4–6 inches locally for the Walnut configuration and 5–10 inches where the two dams’ benefits combine. Those reductions can be the difference between nuisance flooding and property damage for many homeowners and infrastructure downstream.

Cost and funding hurdles: Barrett presented order‑of‑magnitude construction estimates — approximately $100 million for Birch Creek and $200 million for Walnut Creek. He told directors that projects of this scale typically require state and federal funding. The SJRA analysis initially met FEMA’s benefit‑cost threshold once FEMA’s social benefits (economic and societal impacts beyond direct property damage) were included; Barrett said FEMA later removed those social benefits from the calculation, leaving the BCR below grant thresholds and complicating eligibility for federal dollars. “When we inserted the social benefits you can see we did achieve over a 1 benefit cost ratio,” Barrett said, “but currently the social benefits are not part of the process.”

Land‑use conflicts and mitigation: the study also identified land uses inside proposed inundation footprints: Barrett said a planned residential development (Woodhaven) lies inside an early Birch Creek footprint, and an existing solar array overlaps portions of the Walnut footprint. He said the study factored relocation costs for approximately 100 acres of panels and that moving panels to alternate sites was considered feasible as part of project planning.

Bear Branch Dam condition: SJRA’s operations director, Ed Shackelford, briefed the board separately on the Bear Branch Dam’s concrete spillway and joint problems. Shackelford said gaps in construction joints have allowed water to pass and erode material under the spillway slab; consultants warned the slab might be susceptible to uplift if water gets underneath. The consultant’s recommendation, Shackelford said, was “a more comprehensive approach to rehabilitating both the service and auxiliary spillway” and urged prompt action. He summarized funding to date: a $3.6 million congressional allocation (from Congressman Crenshaw’s office), local MUD participation for part of the local share, and a phase‑2 auxiliary‑spillway estimate of about $7.1 million, placing total project costs in the mid‑millions (project total presented as roughly $14 million with engineering, testing and inspection).

Board response and next steps: multiple directors described the condition as urgent, noting populated neighborhoods near the inundation footprint. Directors asked whether the township could help accelerate work through letters of support, bonding, or by coordinating MUD participation. SJRA said it lacks taxing authority and needs an identified project owner or sponsor that could pursue reimbursements and long‑term operations funding. Barrett and Shackelford urged officials to pursue letters of support and legislative outreach; Barrett said SJRA had broached offices of several congressional representatives and that additional advocacy would follow the final report. The board voted to accept the SJRA update and asked staff to return with options and a September agenda item to consider letters and other steps.

What’s next: SJRA will share its final report with elected officials and stakeholders, and the board asked staff to explore bonding, outreach to state and federal lawmakers, and MUD commitments to shorten the project schedule. SJRA cautioned that even with accelerated funding the design, permitting and construction timeline would likely run years; under an optimistic schedule design could start in 2026 with construction in later years and completion into 2029.

Sources: Presentation and Q&A with Matt Barrett and Ed Shackelford of the San Jacinto River Authority to the Woodlands Township Board of Directors (public meeting).