SJRA Unveils 10-Year Flood-Mitigation Plan

8/4/2025 – The San Jacinto River Authority (SJRA) has unveiled a ten-year flood-mitigation plan for the river basin. For the most part, it’s built around continuations of previous efforts. Regardless, it’s interesting to see what SJRA hopes to focus on in the future.

The plan contains eight main elements:

Spring Creek Watershed Flood-Control Dams Feasibility Study
Upper San Jacinto River Basin Sedimentation Study
Lake Conroe/Lake Houston Joint Reservoir Operations Study
San Jacinto River and Tributaries Sediment Removal and Sand Trap Development
Waller County Flood Mapping Updates
Upper Basin Dual Purpose Reservoir (Flood/Water Supply)
Rain and Stream Gage Installation
Miscellaneous Flood Management Projects

Let’s look at each.

Spring Creek Watershed Flood-Control Dams

Previously, the SJRA identified two potential sites for flood-control dams in the upper Spring Creek watershed. The sites included properties along Birch and Walnut Creeks. One of the sites subsequently was sold for a solar farm. However, SJRA believes it only needs a small portion of that property. It has budgeted money to buy that property and relocate some of the solar panels.

Matt Barrett, SJRA Flood Management Division Manager said, “We believe it is still a feasible site if we can identify a project sponsor to own and maintain the dam/reservoir.”

Currently, SJRA is seeking partners who could help fund land acquisition, construction and maintenance.

As with many of these items, SJRA emphasizes that it only has money for planning, coordination and project leadership, but not actual execution. For that, it must rely on grants.

Upper Basin Sedimentation Study

SJRA started this project several years ago also. The presentation shows them wrapping up their sedimentation study next year. They intend to rank order and develop an implementation plan for all projects that they have identified to date.

Joint Reservoir Operations Study

The goal of this project is to determine the most efficient and safe way to coordinate the operations of Lake Conroe and Lake Houston during floods. However, construction delays on Lake Houston’s new floodgates have delayed the completion of the study. That’s because engineers must understand the total release capacity of Lake Houston’s gates to make plans.

When last I checked, the City planned to adjust the number of gates to fit available funding. Once the release capacity has been locked down, engineers can develop:

An inflow forecasting tool for Lake Houston
Gate operations policies
Feasibility of pre-releases at either or both reservoirs
Risk evaluations in different weather scenarios.

SJRA hopes to complete this project by 2028.

Sediment Removal and Sand Trap Development

This project started in 2020 and identified a test site near the Hallett mine on the San Jacinto West Fork. SJRA wanted the site to be near a mine so miners could remove accumulated sediment from the sand trap once it filled up.

However, after the site was identified, the recommended site was subsequently cut off by a “pit capture.” The river is now flowing through the Hallett pit rather than around it.

The question in my mind is whether the pit walls can be hardened or vegetated somehow to let the exposed pit function as the sand trap.

SJRA hopes to work with a consultant to simplify the design and reduce costs for all involved. They see project completion in 2028.

Waller County Flood Mapping

SJRA hopes to obtain a grant from the Texas Flood Infrastructure Fund to update Waller County’s flood maps to Atlas 14 standards. This project could go through 2029 and cost $7 million.

Upper-Basin Dual-Purpose Reservoir

This is one of the most exciting elements of the 10-year plan. This feasibility study would determine the most viable location for a new lake/reservoir in the upper river basin that could mitigate flooding and supply water.

The study will look at a number of constraints and work with stakeholders, such as the US Forest Service.

Depending on the feasibility of the ultimate recommendation, it could replace a number of preliminary recommendations from the River Basin Master Drainage Plan developed several years ago. The study would go through 2029.

Upper San Jacinto River Basin — *A new dual-purpose reservoir could be sited north of Lake Conroe or in the East Fork Watershed.*

Rain/Stream Gage Installation

SJRA, working with counties, precincts, and other local governments, has identified 48 locations for rain/stream gages across the upper river basin. SJRA has incorporated all of them in the Regional Flood Plan.

As funding becomes available, they would be constructed. SJRA projects this project could last through 2032.

Miscellaneous

In the latter phases of the 10-year plan, SJRA is reserving some money for miscellaneous projects that arise through 2035. They might be small scale follow-up studies or facilitation of major construction projects – when/if they come to pass.