Tag Archive for: BMP

Sand Mine Dike Remains Open for Years

In my last post, I talked about how certain sand mines on the San Jacinto could help reduce the rate of sedimentation in the river by following best management practices (BMPs) found in other areas. Those BMPs included:

  1. Locate mines outside of floodways.
  2. Establish performance bonds to cover the cost of cleanup.
  3. Increase the width of dikes.
  4. Decrease the slope of dikes.
  5. Control erosion with vegetation.
  6. Replant areas not actively being mined.
  7. Avoid clearing areas that will not soon be mined.
  8. Protect stockpiles from flooding.
  9. Mine only above the thalweg (deepest part of the river).
  10. Establish performance bonds to guarantee remediation of breaches and/or repurposing of mined areas once mining is complete

This Mine Missed 9 out of 10

The State of Texas does not require these BMPs for sand mines on the San Jacinto. But it should. Here’s a case study in what happens if you ignore these principles.

The wide shot below was taken in January of 2010. Notice the muddy brown area in the middle of the shot. Also notice the breach in the dike on the left hand side of the brown area and the stockpile right above it. Finally, notice that un-vegetated area in the point on the far left.

That’s where the original mined area was back in the 1980s. Whoever mined it at that point took sand directly from the river bank. Regardless, it was never replanted and the entire area remains vulnerable to erosion to this day.

That’s important because this mine, like all but one on the the West Fork, lies largely in the floodway. See the cross-hatched area below in the USGS flood hazard map.

As a result of being in the floodway, here’s what happened to it during Hurricane Harvey. Note multiple breaches in the dikes, the loss of the stockpile, and swirling floodwaters flowing through the mine from upper left to lower right. Finally note that Harvey inundated that original mined area that was not replanted.

This made me curious, so I reviewed the historical imagery for this location in Google Earth. Here’s the same mine in 2016. Same story. Just not quite as bad. They lost about a third of the stockpile. And nasty brown water flowed straight through the pits closest to the river.

Next, I zoomed in on the breach and scrolled back through time. It first showed up in 2006.

By early 2011, they were building roads out to the breach.

Here it is in late 2011. Note how the river below the breach has become clogged with sand.

In 2013, still wide open. Another flood. More sediment flushed downstream.

In 2014, still open!

In 2016, they’ve rebuilt the dike! But it’s skinny. Very vertical. Un-vegetated. And you can already see cracks and major signs of erosion developing in it.

Then along comes another flood at the end of the year.

And by the next day, most of the dike has been washed away.

By 2017, it was fixed again.

Then along came Harvey. And there it went again.

Spike the Dike

So how did this mine score overall? If you were applying these principles, it received an almost unperfect score.

  1. Locate mines outside of floodways.
  2. Establish performance bonds to cover the cost of cleanup.
  3. Increase the width of dikes.
  4. Decrease the slope of dikes.
  5. Control erosion with vegetation.
  6. Replant areas not actively being mined.
  7. Avoid clearing areas that will not soon be mined.
  8. Protect stockpiles from flooding.
  9. Mine only above the thalweg (deepest part of the river).
  10. Establish performance bonds to guarantee remediation of breaches and/or repurposing of mined areas once mining is complete

The breach first showed up in 2006 and was still open in 2014! Goin’ for the record! How much sand and sediment wound up downstream as a result?

No telling exactly. But whatever it was, they won’t be picking up the tab for the cleanup. You will be (Point #10)…which underscores the need for the State to adopt common sense guidelines like these. Perhaps if it had, we wouldn’t have had as much damage during Harvey.

As always, these are my opinions on a matter of public policy, protected by the First Amendment of the U.S. Constitution and the Anti-SLAPP statutes of the great State of Texas.

Posted on August 3, 2018 by Bob Rehak

339 Days since Hurricane Harvey