An estimated 25,000 gallons of untreated wastewater spilled into the San Marcos River and a nearby storm drain Wednesday morning after contractors broke a wastewater main.
Contractors broke one of two 20-inch wastewater force mains from the main lift station to the San Marcos Wastewater Treatment Plant while working on the Woodlands project (formerly known as Cape’s Camp) on River Road between the IH-35 Access Road and Cape Road, according to a city press release. The main broke at 7:45 a.m., causing a wastewater discharge that reached the San Marcos River. City crews arrived within 10 minutes of the break.
An estimated 15,000 gallons of untreated wastewater spilled into the river.
Jon Clack, assistant director of Public Services, said the river would be difficult to clean because “once it hits the river, it’s pretty much gone.”
“So the river is actually doing the cleaning itself,” Clack said. “I’m not sure what the spring flow is right now, but there’s a lot of water coming down the river, and this—while a sizable spill—it wouldn’t have been that big of a shock to the river.”
Because the wastewater did not “hit” the river all at one time but spilled over a several-hour period, the river did not receive “one big shock,” Clack said.
The spill was “time-released,” Clack said. The river flow will help dilute and disperse the wastewater that spilled into it.
The river will remain open and will not be closed to swimmers or recreational activities, he said.
“The further (the wastewater) goes down the river, the more diluted it becomes—the more dispersed it becomes,” Clack said.
The spill took place below any of the public access sites to the river in an area where the public would not be, Clack said. There should not be any health effects to the river.
City crews stopped the discharge by closing valves that isolated the broken section of the force main, the release said.
The other 10,000 gallons of wastewater that did not enter the river went into a storm drain and was pumped out and taken to the wastewater treatment plant before it reached the river, Clack said.
“We were able to capture a lot of it within the storm sewer system,” he said.
The broken force main has now been repaired, Clack said. Since there are two force mains at that location, the one that broke was turned off and the other main remained in operation.
This way there was no interruption of service to city utility customers, he said.
San Marcos will report the incident to the Texas Commission on Environmental Quality as required by regulation, according to the press release. The city will charge the contractor for repairs to the wastewater line and for any expenses incurred as a result of the spill.