From Erosion to Explosion: Why It’s Dangerous to Mine Sand Near Streams and Pipelines
Mining sand near pipelines can expose the public to danger through erosion. We’ve seen this at the Triple PG sand mine in Porter where a potentially lethal combination of circumstances came together. 1) MINING 2) in a FLOODWAY 3) too close to PIPELINES 4) created EROSION 5) that undermined and EXPOSED the pipeline 6) to FLOATING DEBRIS and 7) the FORCE of floodwater.
Excavating pits in floodways causes erosion to move upstream and downstream during floods. When the pit is too close to infrastructure, such as bridges (or pipelines), erosion can then threaten their foundations.
Headward erosion is a PREDICTABLE phenomenon. It’s as certain as gravity causing dirt to fall into a hole. Except in the case of the Triple PG sand mine, floodwater gave gravity an assist. It pushed the dirt into the hole. The hole, in this case, is the sand pit on the left below. The floodwater came from the top of the frame.
This doesn’t happen every day. It’s sporadic. It happens during floods. But that makes it no less predictable.
How Triple PG Grew Toward, Between and Past Pipelines
The images below show the growth of the Triple PG Sand Mine northward into Montgomery County. In 1995, the mine was 2,000 to 3,000 feet away from the pipelines.
The mine kept expanding to the west and north. Just before Harvey, notice how Triple PG had mined right up the pipeline and beyond it, into the danger zone between the pipeline corridors.
Then came Harvey.
During Harvey, headward erosion took out about a 200-foot wide section of earth supporting the natural gas pipeline (also seen in the helicopter photo above). Harvey also elongated the lake in the middle of the pipeline corridors.
Then in 2019, this area had a major flood in May and Tropical Storm Imelda in September. The major breach widened and the lake elongated even more.
Imelda widened the Harvey breach so wide and deep that it exposed more pipeline. (See photo below).
Exposed pipeline has no protection from floodwaters carrying trees, cars, houses or other debris downstream. A major collision could cause an explosion. But that’s not even the biggest potential catastrophe at the Triple PG mine.
Now … For the Real Disaster Scenario
Looking at a wider satellite image (below), we can see that the mine is now closing in on the HVL pipelines from the south AND the north. It brackets them.
Water flows from top to bottom in the image above. Note how Caney Creek bends near the white line above. During Imelda, floodwater cut through that area into the big northern pond at this bend instead of following the natural stream bed. See below.
Without constant repairs like you see above, Caney Creek could soon reroute itself through the big pit on the left below. Erosion on both sides of the utility corridor could expose the HVL pipelines – just as it did the natural gas pipelines. Not likely, you say?
In the last three years, the two ponds along this line have grown closer together by more than 1000 feet. The ponds now are within a few feet of actually touching the pipeline corridor on both sides. Continued erosion could soon threaten the HVL pipelines in the middle if nothing is done to stop it.
Why is This Potentially MORE Dangerous?
Compared to exposing a natural gas pipeline, exposing liquid pipelines is far more dangerous.
When a natural gas pipeline explodes it creates a fireball that could kill anyone near it.
But when HVL pipelines rupture, they spew poisonous liquids. And if those pipelines rupture during a flood, those poisonous liquids will flow right into the source of drinking water for two million people – Lake Houston. This is why sand mining in floodways near pipelines is a bad idea.
Most of us have seen news footage of pipelines that ruptured on the San Jacinto River. Floodwaters swept away barges that collided with pipelines and caused them to explode. Could something comparable happen here with trees or cars floating downstream?
Enter James Cameron stage right.
Posted by Bob Rehak on 12/7/2019 with help from Josh Alberson
830 Days since Hurricane Harvey and 79 since Imelda
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.