The rapid growth of sand mining along the San Jacinto has contributed to an increasing rate of sedimentation of the river and Lake Houston.
Consequences of Increased Sedimentation
Sediment has contributed to:
- Flooding that cost residents and businesses billions of dollars in damages during Harvey.
- Forcing taxpayers to spend tens, if not hundreds of millions of dollars in dredging costs to restore the river’s carrying capacity and reduce flood risk.
- Decreasing the capacity of Lake Houston at a time when the City is about to add 1.5 million users to it’s main water system.
- Increasing the City’s water purification costs, which are passed along to customers.
- Impairing fish populations and recreational opportunities
Ignoring Best Management Practices for Buffer Zones
Following best management practices that are common in other states – especially those that mandate buffer zones between mines and rivers – might have prevented or reduced many of these problems. But those practices were not followed here; miners mine so close to the San Jacinto that dikes are broken repeatedly. When caught, miners pay fines averaging $800.
The Lone Exception In Texas
With one exception, Texas has shown little desire to force miners to follow best management practice for setbacks in flood prone areas. That exception is the John Graves Scenic Riverway, a pilot project on a small portion of the Brazos River near Mineral Wells, about 40 miles west of Fort Worth.
Legislation Addressed Water-Quality Impacts from Sand Mining
The legislation that created the Riverway forms a precedent for imposing stricter regulations on sand mining in the Houston region. The name “Scenic” belies the major purpose of the legislation, which was to address water-quality impacts from rock, and sand and gravel mining operations.
Perhaps there’s an opportunity to create a protected area much like that one here.
Statewide Survey Found Widespread Noncompliance
The TCEQ conducted a statewide survey of 316 quarries in 62 counties, beginning in April, 2004. It revealed that noncompliance with permits was a statewide problem. It also revealed that noncompliance sometimes resulted in significant detrimental effects to water quality. One such area was the one that eventually became the John Graves Scenic Riverway area, where best management practices were not being followed.
Key Elements of Legislation Protecting Water
Legislation that formed the area focused on stormwater discharges and their effect on water quality. Key provisions included:
- Stricter erosion controls and effluent limits
- Reclamation of quarries and financial provisions to ensure reclamation
- Restoration of receiving waters in the event of an unauthorized discharge
- Prohibition of mining within two hundred feet of the river and the hundred-year flood plain
- Prohibitions against locating quarries in areas subject to frequent flooding.
Model For San Jacinto
The San Jacinto River, one of the main sources of the area’s drinking water, flows through, not around, sand mines on a regular basis. The mines are not only located within the 100-year flood plain, many are located within the FLOODWAY! This means they are in the main flow of the river during floods and experience higher velocities. Approximately 150,000 cubic feet of water per second flowed through these mines during the peak of Harvey, washing out roads and dikes.
USGS Maps Show Mining in Floodway
Twenty-square miles of exposed sand and sediment exist within these mines between I-69 and I-45. This screen capture below is just upstream from I-69.
Other sand mines farther upstream are in the 100-year flood plain as well. Some are also in the floodway. See for yourself.
Photos Contradict TACA Claims
TACA, the Texas Aggregate and Concrete Association, claims that water “backs into mines during floods,” but quite the opposite is true; it roars through them, ruptures roads and dikes, and carries exposed sand downstream.
Other tributaries contribute sediment to Lake Houston and the West Fork. However, other tributaries do not have 20 square miles of exposed, unprotected surface on their banks in the form of sand mines. And other tributaries are not flushed with an additional 80,000 cubic feet of water per second when Lake Conroe opens its flood gates as it did during Harvey.
Mines Contribute to Loss of River and Lake Capacity
Lake Houston is losing capacity at a rate of increase that parallels the rate of growth in sand mining.
Houston City Council Member Dave Martin says that the San Jacinto River and Lake Houston will soon supply drinking water to more than two million people, including residents of Houston, Humble, Bellaire, Jersey Village and other cities.
However, Lake Houston is rapidly losing capacity because of sedimentation at a time when demand for its water is increasing exponentially.
Mines Contribute to Turbidity, Increasing Water Treatment Costs
When the State protected the Brazos in the early 2000’s, sand mining was not nearly the problem on the San Jacinto that it is today.
Every time it rains, turbidity in the water increases the City’s water treatment costs, by 20% to 100%, according to Houston City Council Member Dave Martin. “We also see significantly more challenges in capturing and removing the solids through the plants dewatering facilities.”
USGS shows how the clarity of Lake Houston changes before and after every major storm.
Add Dredging Costs to the Damage Assessment
Dredging a tiny 2.1 mile stretch of the West Fork of the San Jacinto is likely to cost taxpayers up to $70 million – and that does not even include the giant bar at the mouth of the West Fork that is backing water up, contributing to flooding, rerouting the river through neighborhoods and threatening infrastructure.
That estimated $70 million is just the tip of the iceberg. Maintenance dredging that returns the river and lake to their original design capacities could cost far more.
$70 million covers dredging only from River Grove Park to a few hundred yards past the West Lake Houston Parkway Bridge. It does not include the East Fork, the West Fork between Fosters Mill and the Lake, the giant mouth bar at the junction of the West Fork and the Lake, Lake Houston above the FM1960 Bridge, or West Fork upstream from River Grove.
That’s an additional 13+ miles. And keep in mind that the U.S. Army Corps is only dredging to pre-Harvey depths. Returning the lake and river channel to their original 100-year flood design capacity would require deeper dredging. That would cost more per mile than the current project between River Grove and Kings Harbor.
Make Mines Part of the Solution, Not the Problem
Prohibiting mining within the 100-year flood plain will create a natural buffer between mines and the river that can trap sand before it becomes a problem.
As mines play out in the area between I-69 and I-45, they can help solve our sedimentation and flooding problems by being:
- Restored as wetlands
- Refilled to their natural grades with the spoils from dredging
- Turned into detention ponds.
Previously, some miners have remediated sand pits after they played out, but many others have not. This pit, for instance, one block north of Townsen next to North Houston Ave. in Humble has been left unfenced, ungraded and unplanted for years. It currently poses a danger to children who play in it and businesses building around it.
Fortunately, the U.S. Army Corps of Engineers plans to use this pit and one other as a placement site for the spoils from its current emergency dredging project.
Let’s create a protected waterway on the San Jacinto, much like the John Graves area on the Brazos.
Posted July 1, 2018 by Bob Rehak
306 Days since Hurricane Harvey