http://www.decaturdaily.com/decaturdaily/news/070705/overflow.shtml

 

Fewer sewer backups in Decatur
Improvements, less rainfall lowered number of overflows, DU reports

By Catherine Godbey
cgodbey@decaturdaily.com · 340-2441

A map of Decatur lay on the table in the Decatur Utilities boardroom.

Three red dots pinpointed spots on the map.

“There sure are a lot less red dots than last year,” DU Electric Manager Dan Gibbs said.

Last year, the members of Decatur’s Municipal Utilities Board examined a map spotted with 27 dots. Each dot represented the location of a wastewater overflow.

“The procedures we put into place seem to be working,” Stan Keenum, DU interim general manager, said. “Of course, we’ve had a lot less rain this year.” The lack of precipitation accompanied with improvements made to the waste-water system resulted in a decreased number of overflows.

According to DU, overflows this year resulted from line blockages of roots and foreign objects. Rainfall has yet to contribute to a waste-water overflow.

Rainfall

Keenum identifies the low amount of precipitation as the main reason for the low overflow numbers. Rain increases the amount of groundwater and pressure on the pipes.

“When there is more pressure,” Keenum said, “water leaks through the cracks and can cause an overflow.”

As rain increases, so does the likelihood of an overflow. During periods of heavy rain, water in the system escalates because of standing water that runs over the top of manhole covers.

To decrease the amount of overflows caused by the rain, DU spends more than $1 million a year to repair pipes and manhole covers.

DU crews inspect the pipes and manhole covers for cracks, which occur from eroding materials, loose joints and growing roots.

These examinations lead to the rehabilitation of over 100 manhole covers and hundreds of feet of pipe. Depending on the level of damage, either a contractor will repair the pipe or DU will replace a whole section of line. “We have done rehabilitation work for 10 to 12 years,” Keenum said. “The biggest way we know we’ve made improvements is in the reduced amount of overflow gallons and time of the overflow.”

This year 540 gallons overflowed, compared to previous years when overflow number equaled more than 8 million, 6 million and 44 million gallons.

“Years back overflow lasted for two to three days, now they last two to three hours,” Keenum said. “This tells us less water is getting in the pipes and we are getting rid of it faster.”

Residents can help alleviate the possibility of an overflow. Keenum advises homeowners to make sure that their clean-out caps are secure.

Clean-out caps are located on the sewer line that runs from a house to the street. Any excess water, Keenum said, can result in a wastewater overflow.