West Fork or Spring Creek: Which Contributes More Sediment to Lake Houston?

As the Lake Houston Area grapples with dredging, sedimentation surveys, sand trap studies and more, it’s important to understand where sediment comes from.

Month after month, I fly up and down the West Fork of the San Jacinto. More often than not, the confluence of Spring Creek and the West Fork (just west of I-69) looks like this.

West Fork (top) shows much more silt despite more flow coming from Spring Creek (left).

What Spring Creek Looked Like on Same Day

On this day (Friday, September 11), we took off from Intercontinental Airport and flew north over Spring Creek. Spring Creek looked like this.

Spring Creek north of Intercontinental Airport. Note how you can see the sandy bottom.

The difference in the water clarity is readily apparent. Yet in the 2000 Brown & Root study the authors said that Cypress and Spring Creeks contributed far more sediment. See Page 14. Sand miners, still quote and re-quote that study every chance they get.

What Accounts for Difference

So what accounts for the difference between the study and current visual observations? Mainly:

  • Upstream development
  • Sand mining
  • Storms that fall over one watershed, but not the other, on any given day

Twenty years after the Brown & Root study:

  • The heaviest development has shifted north into the West Fork watershed
  • Sand mining has expanded exponentially on the West Fork
  • Storms continue to fall over one or both watersheds.

Brown & Root’s findings on this one narrow issue (source of sediment) no longer reflect current conditions and visual observations.

Twenty square miles of sand mines between I-45 and I-69 have widened the West Fork tremendously since then, exposing far more sediment to floodwater. Worse, the mines’ dikes often breach, allowing millions of gallons of sediment to flow downstream. Even worse yet, the mines often pump water over the side of their dikes into the river or surrounding streams and forests.

The result is what you see above. Upstream from the sand mines, water flowed clearly on the West Fork, as it did on Spring Creek. Downstream, the West Fork looked like a sewer. The pictures below show some of the reasons.

Unless, otherwise noted, all the photos below were taken on 9/11/2020.

LMI River Bend mine. Not recent repair of breach and drainage ditch filled with silty water.
Same ditch goes under mine entrance. From there, the silty water goes into woods and then the West Fork.
At the LMI Moorehead mine, I spotted this pump.
At the same mine, this pipe and what looks like a fire hose send silty water into surrounding wetlands when the level in the pond at the right gets high enough.
One of the places where silty water enters the river.
Zooming out, you can see the source in the background.
Another mine where silty water leaks out of pits
The water collects in the woods and eventually flows into the West Fork.

The Result

This is the end result. The West Fork (top) is far more silty than flow from Spring and Cypress Creeks (left).

A Sampling of Previous Flyovers

West Fork (right), Spring Creek (left). Photo taken on 10/2/19.
West Fork (right), Spring Creek (left). November 4, 2019
West Fork (right), Spring Creek (Left). February 13, 2020
West Fork (top), Spring Creek (left). March 6, 2020.

I’m sure that when Brown & Root did its survey twenty years ago that Spring and Cypress Creeks contributed more sediment to Lake Houston. Today, however, I believe the West Fork contributes more.

It’s important to get this right if the community is to develop strategies that reduce the long term rate of sedimentation and save dredging dollars.

Posted by Bob Rehak on 9/18/2020

1116 Days after 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.