Improved water quality reports for the Ohio River throughout the summer indicate that new storm sewers along Cincinnati's waterfront are making the river cleaner, a health official said.
Weekly samplings of the river testing for fecal coliform bacteria, a measure of raw sewage bypassing treatment plants, showed improvement during the past two summer boating seasons, according to Cincinnati Health Department findings.
Of 28 weekly sampling tests this spring and summer, three rated the Ohio's water quality as unhealthful for recreational use, the same number as a year ago.
The unhealthful rating is intended as a warning that boaters and swimmers are at risk of becoming sick if they contact bacteria-laden river water.
Water quality was rated good for 11 weeks and moderate for 14 weeks this year, an improvement from 17 weeks of moderate ratings in 2001.
The readings show a gradual trend toward cleaner river water that appears to be a result of storm-sewer improvements made when Cincinnati rebuilt a stretch of downtown highway in 2000.
A dry summer this year also reduced the amount of rain water that could rush untreated sewage through treatment plants and into the Ohio.
In 1998, before the Cincinnati road and sewer improvements began, the river's water was rated unhealthful seven times.
"There have been continuous improvements to the system," said Malcolm Adcock, Cincinnati's health commissioner. "I think those improvements are beginning to show the fruits of their labor."
However, environmentalists are demanding that more improvements be made.
Heavy rains still can overwhelm Cincinnati's old sewers - some of which date to the 19th century - and flush untreated sewage past treatment plants and into the Ohio River.
Sewer and sanitation districts on both sides of the river have begun a series of multimillion-dollar construction projects designed to reduce and eventually eliminate the sewer overflows.
The Ohio, which runs from Pittsburgh to Cairo, Ill., is a drinking water source for about 3 million people.