Marble Falls eyeing groundwater system for south of bridge

Lake Marble Falls. Staff photo by Nathan Bush
A $7 million groundwater system could increase the city of Marble Falls’ water capacity by about 720,000 gallons a day — around half of what the city now treats out of the lake. The City Council approved a contract for the system’s potential purchase at its regular meeting on Tuesday, March 21.
The purchase is not yet official. A 180-day feasibility study, which councilors also approved at the meeting, will dictate what happens next. The total cost of the study is $82,960.
“This will be a future action that we will bring back to (councilors) once we draw to the end of the feasibility period and we have a lot more of the quantifiable details for (councilors) to be able to evaluate to make a decision on final acquisition,” Assistant City Manager Caleb Kraenzel said.
Marble Falls can opt out of the purchase at any time during the 180-day window. If the city did move forward with the acquisition, the purchase would still need approval from the Public Utility Commission of Texas.
The Capstone Water System is located east of U.S. 281 and adjacent to FM 2147. It encompasses roughly one acre of real property.
It currently serves about 30 customers but is permitted by the Central Texas Groundwater Conservation District to pump roughly 500 gallons of water per minute.
The acquisition would accommodate the city’s growing population by increasing water volume, Kraenzel said.
“The well (can) pump 720,000 gallons of water per day. That’s roughly half of what we are currently treating out of the lake, in terms of surface water,” he explained.
Currently, the city only uses water from Lake Marble Falls as a firm water customer of the Lower Colorado River Authority. Recreational activities such as swimming and boating, along with natural factors, make cleaning that water costly.
“The lake water is usually biologically more sophisticated to treat in the water treatment plant than the Type I water that comes out of the wastewater treatment plant,” Kraenzel said. “That’s how dirty lake water is.”
The cost to purify groundwater is much cheaper, he said.
“It’s groundwater, so it’s much more cost-effective to treat,” Kraenzel said. “It doesn’t require half of the chemicals and treatment processes as a surface water plant.”