Proof is in results, engineer says
It all sounds good, but the less-costly alternatives do not work, said engineer Steve Sewalk of the EADS Group in Johnstown. EADS serves as the engineer for the city, the redevelopment authority and several other municipal sewage agencies.
Sewalk shows readouts from 160 meters installed to measure flow rates from various communities as sewage enters the Johnstown Regional Sewage main lines, also called interceptors.
All of the communities with complete reconstruction and residential pressure testing have maintained acceptable flow rates during periods of heavy rain, he points out. None of the systems with less complete projects have come into compliance.
A graph showing outflow from East Conemaugh Borough is the most dramatic, with an abrupt and permanent drop from the day the new sewer system was switched over.
“They have proven you can fix the problem,” Sewalk said. “We deal in proof, not theory.”
‘It’s a learning curve’
It isn’t a new issue, said Highland Manager Ed Engelhart. The Richland Township-based authority has been working to reduce inflow and infiltration for more than a decade. Highland customers have been required to have pressure testing when any property is sold. Highland crews go out and check neighborhoods during virtually every heavy rainfall.
The first issues Highland looked at included downspouts, basement drains and storm sewer connections, Englehart said. Other projects have attacked the problem with a variety of strategies, from smoke and dye testing up to replacing everything except the homeowners’ connecting pipes. Now Highland is going through its neighborhoods, with its own crews installing new sewers with the same criteria and homeowners’ requirements being used in the city and other successful systems.
“It’s a learning curve,” Englehart said. “There is nothing you can do to fix the problem unless you basically go in and put in a whole new system.”
Brownstown Borough engineer Dan Carbaugh of Hollidaysburg-based Keller Engineering agrees. He points to another neighboring community’s attempt to put in a new system and have homeowners sign documents saying their connections are sealed.
“Their average daily flow was something like 250,000 gallons,” Carbaugh said. “The first rainfall, it went up to 4 million gallons.”
Part of the problem, Carbaugh said, is that many older homes have terracotta pipes, made from clay, connecting to the sewers. Not only are the old pipes breaking and leaking, sometimes they were deliberately installed with gaps to allow groundwater to enter.
Even removing the direct connection from a downspout doesn’t keep that water out of the sewer in those homes, he explained.
The runoff seeks the easiest path and runs down the foundation wall into the gaps in the lateral pipe.
Daisytown Borough tried the smoke and dye approach, following up with house-to-house inspections to remove sump pumps and hidden downspouts, Sewalk said.
“We did all that and there are still problems,” Sewalk said. “I think Daisytown is a microcosm of the whole system.”
Randy Griffith covers Johnstown Redevelopment Authority for The Tribune-Democrat. Follow him on Twitter at twitter.com/photogriffer57.