Even as Colgate Creek returns to its "normal" polluted condition after a 10-million- gallon sewage spill two weeks ago, Baltimore City officials are being pressed by federal and state regulators - and by concerned residents - to justify their management of the city's aging wastewater treatment system.
Two major spills in recent months have highlighted the vulnerability of the city's nearly century-old sewage treatment network, once hailed as a model of sanitary engineering.
Overflows into Colgate Creek on Sept. 8 and 9, and another of nearly 5 million gallons to the Jones Falls in late July, have raised questions about the city's upkeep of a system that is vital to preventing disease outbreaks and to maintaining the health of Chesapeake Bay.
"The sewer infrastructure is very aged, and it seems to be breaking more," said Rich Hersey, executive director of the Herring Run Watershed Association, a citizen group dedicated to restoring that degraded East Baltimore stream. "We see gray water, and people smell the stuff in our streams."
At a news conference yesterday, city public works officials defended their maintenance of the sewer system, and their handling of the spills.
"Most of the time, these are situations we have no control over," said George L. Winfield, the city's director of public works.
When an underground pipe gets blocked or a valve breaks, he said, the city must often divert raw sewage into the nearest stream to keep it from backing up into homes or overflowing into the streets.
"It's always a last-resort decision," Winfield said, stressing that he and other city officials care about the environment. He acknowledged that there had been "communications breakdowns" in not notifying the public of either major spill, but vowed to see that future overflows are reported promptly.
City officials said yesterday that fecal coliform bacteria levels in Colgate Creek, which flows through an industrial area in southeastern Baltimore, have returned to normal. But Dr. Peter Beilenson, the city's health commissioner, said the signs posted along the stream warning of polluted water will remain, because bacteria levels are still five to six times the level considered safe under state standards.
A nonprofit environmental group, Safe Waterways in Maryland, says it measured up to 800 times the safe level in tests taken this week.
Even before the recent major spills, state and federal environmental agencies had launched investigations of sewage overflows in Baltimore and in the surrounding suburbs.
Officials of the Maryland Department of the Environment and the U.S. Environmental Protection Agency say they are mulling action against the city and neighboring counties for not preventing more spills through better maintenance of their facilities.
They also are looking into whether the city and other localities in Maryland are reporting sewage spills promptly. All overflows are to be reported by telephone within 24 hours, with a follow-up letter within five days of the incident, according to state officials.
Sewage discharges are one of the leading causes of stream pollution in the country, according to Bradley Campbell, EPA's mid-Atlantic regional administrator. Most spills result from aging and badly designed wastewater treatment systems, he said.
EPA has ordered overhauls of sewage systems in other cities. Sewage overflows so often in Pittsburgh, Pa., when it rains that it would fill Three Rivers baseball stadium 15 times a year, he said.
When Baltimore's system works properly, flushed toilets in the city and the suburbs send 240 million gallons of waste and water coursing through 3,100 miles of pipes, hidden under city streets and tucked away along stream banks. The underground torrent of waste generally flows downhill on its way to two treatment plants on the Back and Patapsco rivers.
City officials acknowledge there have been at least 20 spills or leaks - most of them minor - this year. Data does not exist to indicate whether overflows are more or less severe now than in years past.
"Some of it is breakage, some of it is an older line, but the vast majority of it is clogs caused by carelessness," said Kurt Kocher, spokesman for the city's Department of Public Works. He said maintenance workers have pulled clothing, bicycles, even a washing machine from sewer lines. More common blockages are caused by buildups of grease or tree roots causing the pipes to collapse.
Storms also can cause sewer spills. When Hurricane Floyd blew through Maryland last September, it knocked out power at the city's Jones Falls sewage pumping station - one of 10 used to push wastewater uphill from collection points on its way to the treatment plants. The station had a backup power line, which also failed, causing 24 million gallons of raw sewage to spill into the stream and eventually into the Inner Harbor.