Bob Rehak, board member of the Kingwood Service Association which owns East End Park, said dunes of sediment appeared in the park immediately after Harvey.
“I went down there after [Harvey], and 30 acres of the park was covered with sand—in places the dunes were up to 10-15 feet tall,” Rehak said.
Although the park has since been revived, areas of the park once covered in wetlands now bare a beach-like resemblance with piles of sand sitting 7 feet above the river’s surface. East End Park is one of dozens of areas in and along the East and West Fork invaded by large volumes of sediment carried from Harvey’s floodwaters.
Increased sediment in Lake Houston is cause for concern because sediment deposition in rivers reduces the channel’s capacity, which could exacerbate flooding by pushing floodwaters more quickly into the surrounding areas, according to the Army Corps of Engineers-Galveston District.
The Army Corps determined 1.8 million cubic yards of material—enough to fill the Astrodome 1 1/2 times—needed to be dredged from the river to help reduce flood risks within the Kingwood area.
“As floodwaters moved to lower ground, sediment was swept up within the force of the stormwaters upstream,” said Mike Williford, public affairs chief for the Army Corps. “Eventually, as water slows, finely granulated sediments drop to the surface bottom, creating land masses that once did not exist before.”
There is debate on the cause of sedimentation on the West Fork. Some experts believe sand mining could be contributing to the problem, and Lake Houston area agencies are investigating sedimentation increase in the lake.
Meanwhile, state Rep. Dan Huberty, R-Houston, has filed legislation aimed at increasing accountability and transparency for the sand mining industry.
“Years of unmitigated mining has caused the banks and beds to erode and send exponentially more sand down the river to rest in Lake Houston,” Huberty said via email. “This sedimentation has accumulated such that water can no longer flow evenly to the dam and on to the Gulf of Mexico. We must do something to slow this amassing of sediment in order to prevent future flooding and increase drinking water capacity.”
Digging into the cause
Even before Harvey, Lake Houston’s capacity to hold water decreased since the lake’s dam was built in 1954 from 158,553 acre-feet to 124,661 acre-feet in 2011, according to a report on Lake Houston’s sediment from the Texas Water Development Board.
There is debate as to where excess sediment originates, with some hydraulic experts believing the volume of sediment comes from shoaling, which happens when sediment drops from flowing water and creates land masses, said Michael Garske, an Army Corps hydraulic engineer, in an April 2018 video news release.
Others, however, suspect a large volume of sediment came directly from sand mining operations that speckle the more than 20 miles of the West Fork between Lake Conroe and Lake Houston. There are currently 10 active sand mining companies registered on the West Fork of the San Jacinto River downstream of Lake Conroe, according to the Texas Commission on Environmental Quality.
As development has grown in the Greater Houston area, so has the sand mining industry. According to data from the U.S. Geological Survey, 970 million tons of construction sand and gravel valued at $8.7 billion was produced in the U.S. in 2018—with Texas as one of the leading states for tonnage of produced sand and gravel.
For River Aggregates, a sand mining company located on roughly 750 acres along the San Jacinto River on Hwy. 242, the need for sand has increased exponentially, River Aggregates Managing Partner Rob Van Til said.
Sand mining companies extract sand and gravel from beaches, dunes, or ocean and river banks—such as the San Jacinto River—to sell to companies who create concrete and other construction materials that make up schools, roads and buildings, Van Til said.
“Every person that lives in the state of Texas consumes about 10 tons of aggregate per year,” Van Til said. “Just imagine as the state continues to grow, the demand for aggregate in our schools and houses [grows].”
Ongoing studies, projects
The Bayou Land Conservancy, a nonprofit focusing on Houston-area conservation efforts, evaluated in 2017 the ecological footprint of sand mining operations on the West Fork of the San Jacinto River. The report showed the number of acres of land occupied by sand mines within the flood plain of the West Fork has more than tripled between 1995 and 2017 from 1,308 acres to 5,496 acres.
BLC Executive Director Jill Boullin said the state does not currently have regulations regarding river setbacks—or a minimum distance from the river channel—for sand mining operations. Therefore, the natural erosion of rivers puts sand mining companies located in the floodway, as well as residents in the surrounding area, at risk, she said.
“There is no question that a flood event like [Harvey] erodes the banks of the river and decreases that setback of those mines from the river,” Boullin said. “Next time we have a Harvey event or even a less than Harvey event, one of those dikes could breach and easily flood the river with sand.”
Van Til, on the other hand, disagrees. He said sand mining operations do not effect the way rivers move over time.
“We leave 150-200 feet of bank between us and the river,” Van Til said. “We’re [working] so far from the river that what we’re doing doesn’t have any impact on how the river moves.”
Local agencies are looking to mitigate the sediment in Lake Houston—regardless of where it originates. The Army Corps is continuing its nearly $70 million project to dredge a segment of Lake Houston and move 1.8 million cubic yards of material into two separate sand pits that were once mining sites. The project began in September and is expected to be completed in May, Williford said.
Meanwhile, the Harris County Flood Control District intends to investigate sand mining during its ongoing Upper San Jacinto River Watershed Master Drainage Plan study. Project Manager Jing Cheng said the study—which will begin at the end of March and take approximately 18 months to complete—will identify flood prevention strategies regionwide.
One portion of the study will include launching a vegetation and sediment control task force in mid-2019, which will investigate sand mining as a potential contributor of sediment deposition in the West Fork of the San Jacinto River and Spring Creek, Cheng said.
“If we’re looking at potential sources of sedimentation that may or may not be sand mining,” Cheng said. “We are also going to review pages in sand mining operations … [for] regulations mining operations are required to follow to see if there have been changes.”
Targeting regulations
Although experts have not yet determined whether sand mining companies have contributed to sediment in the San Jacinto River, local legislators as well as nonprofits such as the BLC are calling for stricter regulations on sand mining in river basins. In the 2019 state legislative session, Huberty has filed four bills that could affect sand mining operations on the San Jacinto River if passed: House Bills 907, 908, 909 and 1671.
HBs 907 and 908 directly relate to increasing the penalties for aggregate production operations, which include sand mining companies who fail to register with the TCEQ or violate standards.
Moreover, HB 909 would require the TCEQ to adopt public “best management practices” that sand mining companies would have to model. The bill text does not cite practices for the TCEQ to adopt; however, some states’ best management practices require greater setbacks from rivers, Boullin said.
The bills are aimed at reigning in “bad actors” in the sand mining industry, Huberty said via email. He said the bills further the purpose of a law he sponsored in 2011, HB 571, requiring sand mining companies to register with the TCEQ for the first time.
However, Van Til said he disagrees that sand mining companies are not regulated enough.
“If you feel like TCEQ needs more boots on the ground, that’s fixing the current system, which I don’t oppose,” he said. “Don’t create more bureaucracies because you think the [rules] you created six or eight years ago are not working. You’re just creating more government; you’re not really fixing the problem.”
Correction: The original version of this article included a misspelled word.
