As Wimberley seeks a solution for its wastewater woes, a proposal to bore a pipe under Cypress Creek is leading to consternation from environmentalists and residents alike.
Those plans are part of a proposed wastewater treatment plant (WWTP) that could be operated by a third party. The plan calls for boring, or horizontal directional drilling, under Cypress Creek to accommodate a wastewater pipe.
Geography plays a major role with the proposed pipe under Cypress Creek. If the city chooses to contract with Aqua Texas for the WWTP, the pipe would connect the city’s collection system to Aqua Texas, which is separated by the creek.
In order to mitigate this natural boundary, a boring to transport the raw sewage to Aqua Texas would be placed 10 feet under the creek.
“Yes, of course, we are confident that it is environmentally responsible,” said Wimberley Mayor Susan Jaggers in an emailed statement. “Certainly more so than discharging effluent into creeks and rivers.”
Jaggers cited the city’s current discharge permit with the Texas Commission on Environmental Quality (TCEQ). Proponents of Aqua Texas argue that the company does not have a discharge permit.
However, critics of the Aqua Texas plan say a discharge permit calls for a plethora of storage measures, which protects the city from ever having to discharge. This, in conjunction with the city’s original plan to use the treated wastewater to irrigate Blue Hole Regional Park, would have protected the city from ever needing to discharge.
Robert Tinstman, a former 21-year TCEQ employee, expressed worries about the proposal to bore under the creek.
“What they are proposing is environmentally irresponsible,” Tinstman said. “Pipes have a way of leaking and there was another solution. The city at one time authorized to build a treatment plant on the south side of the creek to negate the need to pass the creek. I’d rather focus on building that plant than building a boring.”
Despite these concerns, experts call horizontal direction drilling a safe method to install underground pipelines.
According to the Texas Directional Boring Contractors, horizontal drilling can decrease surface disturbance while having minimal impact on the environment during the construction phase.
For the change of scope for the wastewater project, drilling equipment utilized will not be in or adjacent to Cypress Creek, with the site of the drilling to take place 100 to 200 feet away, according to the city’s estimates.
The pipe used to carry the wastewater would be high-density polyethylene, a common material used in horizontal directional drilling.
At a Jan. 8 public hearing, principal Stephen Coonan with Alan Plummer Associates Inc., the firm which designed the wastewater project, said the boring under the creek is environmentally safe.
Coonan said the pipe under the creek will be a single piece of polyethylene with no additional components under the water. This, in theory, would protect the pipe from leaking at points of connection underground.
An Aqua Texas spokesperson said that the city of Wimberley – and not the company – will be responsible for the construction of boring under the creek.
“If you go drill under the creek and don’t have extra pipe or sensors to signal when a leak happens, all you can confirm is that sewage is going in and out,” said Raoul Belleau, a Wimberley area resident. “You can be leaking down into these caves and not know.”
Belleau said the city is trying to save money by not including additional piping or sensors, a measure that could be detrimental to the extensive network of minerals and caves that lie below the creek.
As the debate carries on, opinions on the city’s wastewater options differ. A recent move by Wimberley city leaders to not renew its discharge permit, which doesn’t expire until July 2019, was met with criticism by some community members.
“Just because it’s called a discharge permit, does not mean we will discharge,” Tinstman said. “The plan was to treat the water and irrigate Blue Hole Park. This new partnership would rob Blue Hole of the water it needs to irrigate the land.”