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.
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