Aurora faces more sewer-related costs
The Aurora Utility Board is likely to approve another sanitary sewers infrastructure project at a cost of around $430,000. That’s due to an Indiana Department of Environment Management mandate that the city must eliminate all combined sewer overflows including those occurring in 10-year storm events, by the end of 2018.
In addition, in a July 13 letter, IDEM demanded a $1,600 penalty payment from the city after it did not respond to a March 27 letter regarding a $5 million CSO storage project.
Although there was not a quorum present, those attending a special Aurora Utility Board meeting Friday, Aug. 10, seemed to agree a project posed by GRW Engineering was a good idea. Plans were to officially consider the proposal at the 5 p.m. Monday, Aug. 20, utility board meeting and to send IDEM a letter outlining the new proposal and listing all the sewer infrastructure work Aurora has done to meet the IDEM mandate, and the costs.
The proposal would install a 60-inch storage pipe on the river side of and parallel to Judiciary Street to hold the additional wastewater created by rainwater inflow during heavy precipitation. Once the precipitation is over, and a lower flow begins, that stored wastewater would be pumped to the South Dearborn Regional Sewer District treatment plant in Lawrenceburg.
But the pipe will work only if the inflow coming from several locations is rerouted away from the sanitary sewers, said GRW Engineer Joe Tierney.
One of the largest known inflows is coming from the drainage off St. John Elementary School roof, said GRW Engineer George Lewis. The 10,000 square foot roof surface yields 11,000 gallons of water during a one-hour, two-inch rainfall, the definition of a 10-year rain event.
Because of the cost to send wastewater to the SDRSD and treat it, it would cost less for the city to shoulder the expense or part of it and divert that water from the sanitary sewers, said Lewis. Morton Printing also has rainwater inflow, but would cost much less to fix.
“The big one, that’s a storm drain that flows down the hill into Conwell Street,” said Tierney. Aurora Utilities Superintendent said the two houses involved have downspouts and their house water coming into the same pipe.
Still being evaluated is rainwater from the former PSI building at Second and Bridgeway streets, owned by Marty Rahe and housing doctors’ offices for Aurora Casket employees, said Tierney.
GRW and Aurora Utility staff have been checking for downspouts and sump pump drainage connected to sanitary sewers in the downtown, and have found only six or seven sump pumps of around 160 inspections, said Tierney.
“But they all contribute,” he added. The inspectors have about 50 more homes to do, but doubt they will find more than a few with inflow situations. Most of those remaining homes either are empty, or residents are gone in the daytime, so an evening inspection will be scheduled next.
A 10-year, one-hour storm would produce approximately 70,000 gallons of inflow currently. With all the work done so far, if the additional known inflows are eliminated, that would probably remove about 20,000 gallons of rainwater inflow in a 10-year event, leaving about 50,000 gallons of inflow, said Tierney. Installing the 60-inch pipe, 370 feet long, for use when the pump can’t keep up with sending that amount of wastewater to SDRSD, would capture most of the excess inflow.
What if the pipe was extended behind the Applewood Restaurant, asked Aurora Utility Superintendent Randy Turner. Would the additional storage be needed if there were a 10-year rain event?
“We won’t know till we get a two-inch rain,” replied utility board member and councilman Mark Drury. “... Do we have a contingency plan to add on?”
“The ultimate goal is complete capture,” said Tierney. GRW could do a cost analysis including a phase two for an extension.
He distributed a flow-metering summary for Second Street, along with a profile of the proposed storage system, and the probable cost of around $430,000. The project probably could be ready to be bid by the end of the year, IDEM’s deadline. With that, IDEM probably would grant the city the additional time to complete the project, said Lewis.
The previous storage project to which the July IDEM letter referred would have cost $5 million and stored 250,000 gallons in a holding tank. It was outlined in a January letter from Aurora to IDEM indicating it would create a high financial burden on the city.
(In addition to building the storage unit, there would have been the treatment cost for that many gallons ($2.50 per 1,000 gallons) as the tank was emptied and its contents pumped to SDRSD.)
The letter requested more time to complete separating the rainwater from sanitary sewage, after which storage would be constructed “if needed.”
In February, IDEM responded that Aurora must commit to that storage project to be granted additional time.
In a March 2 letter to IDEM, Aurora responded indicating the city would not proceed with the $5 million storage project but, rather, continue with removal of extraneous water sources.
Those present at the meeting including Aurora Mayor Donnie Hastings, Aurora City Manager Guinevere Emery, deputy clerk-treasurer Orem Turner, and, by cell phone, Aurora Clerk-treasurer Benny Turner, discussed getting a bank loan to cover the storage pipe cost, along with the cost of lining the sewage pipe that runs through Lesko Park, for a total of around $500,000.
Any cost to sewage customers was not yet discussed, the city having raised rates 5 percent this month, to be followed by a 4 percent increase next year and a 3 percent increase the year after.
Monday’s utility board meeting, open to the public, will be upstairs in the city building, Third and Main streets.