AUSTIN, Texas — The proposed MoPac South expansion project continues to spark debate in Austin as community members raise concerns about possible environmental impacts tied to the plan.

Austin’s Environmental Commission discussed the project Wednesday night at the Permitting and Development Center.

The Central Texas Regional Mobility Authority says the project would add up to two express lanes along about eight miles of MoPac from Cesar Chavez Street to Slaughter Lane in an effort to address congestion along one of the region’s busiest corridors.

But opponents say they’re worried about potential impacts to water quality, wildlife, and areas surrounding Barton Springs and Lady Bird Lake.

“The Devastation to the environment, and to Lady Bird Lake,” Austin resident Virginia Palmer said.

Austin City Council Member Mike Siegel also voiced concerns about the proposal.

“We absolutely need to push back,” Siegel said. “We don’t need a massive new freeway over this critical water quality zone.”

CTRMA addressed some of those concerns in presentation materials prepared for the meeting.

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According to the agency, the project would include new water quality treatment measures, and the recommended option would not include elevated lanes over Lady Bird Lake. CTRMA also said the proposed option could save express lane users about 14 minutes in each direction.

Some residents, however, remain skeptical.

When asked whether she believes environmental concerns are being taken seriously, Palmer said, “Well, they’re taken seriously by the community and the citizens. But seriously, no, because they want to do what they want to do. They want to build these highways.”

CBS Austin also asked CTRMA how it’s responding to growing community concerns surrounding environmental impacts.

In a statement, the agency said, “We continue to work with the regulatory agencies and our regional partners to address concerns related to the mitigations provided in the draft Environmental Assessment.”

Palmer said she worries Austin is losing part of what makes the city unique.

“We’re going from the classic green city that we were always known as, to a gray city. Concrete,” she said.

The project remains in the environmental review process. CTRMA says it will review and respond to public comments before submitting its final Environmental Assessment to TxDOT.