The City Council on Tuesday voted to lower the requirement for rainwater retention in the South Chickamauga Creek basin.
The move from holding the first 1.6 inches to one inch had been requested by the Home Builders Association and the Berke administration.
Sandy Kurtz, longtime leader of the South Chickamauga Creek Greenway Alliance, said the resolution was "not yet ready for prime time."
She said it was going to bring more flooding and more silt into the creek, which features a nearby greenway that will eventually connect the Tennessee River with Camp Jordan Park in East Ridge.
Ms. Kurtz said the move "also puts our state permit in peril."
She asked the council to "get everybody to the table" on the issue.
Citizen activist Franklin McCallie said the process had not followed "the Chattanooga Way" and that initially the developers were at the table with the city to the exclusion of the other side.
He said the resolution had been ramrodded through with "the citizens left behind."
Former Mayor Ron Littlefield also spoke to the issue, saying he would be glad to take part in upcoming talks and explain why the city earlier had set the stricter standard for South Chickamauga Creek.
He said city officials could change regulations, "but you can't change the law of physics." He said the move would bring additional sedimentation into the creek with a damaging effect.
He said state and federal regulators "will be watching and the city might be liable."
City public works officials acknowledged that the move puts the city out of compliance with its runoff permit, but said mitigation steps would be taken.