A sewer line near Lexington's Hamburg area broke Monday afternoon, and untreated sewage was coming out of the ground in several places, said Mark York, a spokesman for the city's Division of Water Quality.
Sewage was spilling at an estimated rate of 300 to 500 gallons a minute, York said.
City employees had built a dam and were using a pump in an attempt to keep the sewage from reaching an unnamed tributary of Bryan Station Creek. About 90 percent of the spill was being kept away from the creek, York said. A second pump, expected Monday night, should be able to divert all sewage from the creek, York said.
Employees from the state Division of Water had taken water samples along the creek.
The break was noticed between 2 and 3 p.m. by someone at a private pool in the Westwind subdivision, he said. The sewage was coming out of the ground and flowing away from the pool.
In a 30-foot-square area near the intersection of Starshoot Parkway and Flying Ebony Drive, sewage was coming up in four places, York said.
The same pipe broke about a year ago, and it took about a day and a half to repair it. The broken line is a force main, which means sewage is pumped through it from the recently replaced North Elkhorn Pump Station on its way to the Town Branch Wastewater Treatment Plant.
The sewer line is expected to become obsolete in the next year or 18 months as other pump stations in the area are taken off line.
Those stations often overflow during wet weather, as the North Elkhorn station did before its replacement went online in March.
The sewer work is part of the city's consent decree with the federal Environmental Protection Agency. The decree, or settlement, was reached after the EPA sued the city, saying its storm and sanitary systems were polluting streams in violation of the Clean Water Act.
The work is expected to make breaks like Monday's less likely, York said.
The line will repaired Tuesday, he said.