After 3.5 years since Harvey and dozens of helicopter flights up and down the West Fork of the San Jacinto, it never ceases to amaze me. Despite sediment gage readings that say more silt is coming from Spring and Cypress Creeks than the West Fork, the West Fork appears siltier the vast majority of the time.
Misleading Data Used to Kill Meaningful Legislation
Here’s what the West Fork looked like today. Definitely siltier.
Approximately 20 squares miles of sand mines line the West Fork. Problem is, the one sediment gage on the West Fork is upstream from virtually all of the mines. But most people don’t understand that. And that lack of understanding has allowed the mines to claim for decades that they are not the dominant source of sediment.
I’ve even heard miners testify on multiple occasions in the state legislature to that effect. That’s how they managed to kill best-practices legislation and minimum setbacks in the legislature in 2019.
When Brown & Root, the SJRA, City of Houston, Montgomery County, and Harris County Flood Control all cite the same misleading statistics, what’s an ordinary citizen to do?
Only a Sediment Gage Below Sand Mines Will Tell Whether This is Serious
To be fair, the engineers and hydrologists point out that the silt you see above and below may float out into Galveston Bay.
But I would also point out that:
- The giant sand bar above didn’t exist before Harvey.
- Neither did the multiple sand bars blocking the West Fork up to 90% (according to the Army Corps) after Harvey.
- A misrepresentative gage placement, no matter how many times you repeat the sample in different studies, will always yield the same sampling error.
- Most sediment moves during floods and far more sand is exposed to floodwater on the West Fork.
Finally, I would point out that the dikes of sand mines routinely breach and many mines routinely pump sediment laden water into the West Fork.
The point is: we will never really know what’s going on here until we get a gage downstream from the sand mines.
Time Of Essence
When I pointed out the data error caused by a misrepresentative gage location, the partners in the San Jacinto River Basin Master Drainage Study promised to re-evaluate claims they made based on the gage. The originally found, as did Brown & Root, that the vast majority of the sediment is coming from Spring and Cypress Creeks – based on the gage upstream of the sand mines. They also promised to consider installing a new gage downstream from the mines. But nothing has happened yet. And we’re already well into this legislative session.
We’re now into the third month of the legislative session. And until the San Jacinto Master Drainage Plan consultants modify their findings, we’re all at risk. People will likely reference that study for another two decades, just as they have referenced Brown & Root’s. So this is important. Tick tock.
Posted by Bob Rehak on 3/3/2021
1282 Days since Hurricane Harvey