The winning bid for Ottawa’s coming sewer improvement project came in about $300,000 under the engineer’s estimates.

Ottawa city commissioners on Monday awarded the construction contract to Rosetta Construction LLC, Springfield, Mo., which submitted the low bid of $3,584,848 for the project.

The winning bid for Ottawa’s coming sewer improvement project came in about $300,000 under the engineer’s estimates.

Ottawa city commissioners on Monday awarded the construction contract to Rosetta Construction LLC, Springfield, Mo., which submitted the low bid of $3,584,848 for the project.

Professional Engineering Consultants of Topeka, the city’s engineer, had estimated the project would cost about $3.9 million.  

“We are very pleased the bid came in under the engineer’s estimate,” Richard Nienstedt, city manager, said Tuesday.

A good engineer “estimates high,” Nienstedt added, to prepare the city in the event materials and other costs associated with the project increase.

The other six bids for the sewer improvements — called the eastside interceptor project — ranged from about $3.7 million to $4.1 million, according to a city report.

The city plans to borrow about $4.8 million through the Kansas Department of Health and Environment’s low-interest loan program to cover the cost of the project as well as other future repairs and improvements to the system, Scott Bird, the city’s finance director, said.

“The interest rate for the [20-year KDHE] loan will be in the neighborhood of 2.5 percent,” Bird said. “Using the state’s low-interest loan program will save the city around $10,000 on a project of this size, compared to what it would have cost the city to issue bonds to pay for the project.”

In February 2012, the city commission approved an annual 4-percent increase in the city’s sanitary sewer utility fees through 2016 to fund the $4.8 million upgrade. Bird told commissioners in February the rate increase was necessary to pay off the loan, as well as leave enough cushion to account for repairs to the rest of the aging system, which are likely to surface in coming years.

The city’s underground sewer system, part of which is constructed with clay pipe, already might be 100 years old, Jim Bradley, the city’s utilities director, said previously. The system is showing signs of cracking, buckling, separating joints and other stress that is allowing surface water to infiltrate the system, he said.

With the aid of a KDHE loan, the city plans to construct the eastside sanitary interceptor, as well as make other repairs to the system, Bradley said.

The new system would start at the end of East Third Street near the levee, Bradley said, and run parallel with the levee until it reaches Seventh Street. From Seventh Street, it would run along Mason Street to Ninth Street and then to Lincoln Street, he continued. The system would run south on Lincoln Street, then west on 10th Street and angle southwest across Ottawa University’s property and then south along Rock Creek to about 14th Street, Bradley said.

The proposed eastside interceptor came about when the city applied for a Rock Creek sanitary sewer permit to accommodate the Love’s Travel Stop development on the city’s south side on East 27th Street, Bradley said. The KDHE granted the permit with the qualification that the city review the capacity of the eastside interceptor to handle current and peak wet weather flow resulting from the sewer extension and then implement appropriate improvements.

Nienstedt said Tuesday the sewer improvements would pave the way for future development south of I-35.

He estimated construction would begin in late November and would take about two years to complete.

“We are probably still four weeks away from starting,” Nienstedt said. “We have to work through KDHE approval and have a pre-construction conference. The [construction work] probably will begin shortly after Thanksgiving.”

Doug Carder is senior writer for The Herald. Email him at dcarder@ottawaherald.com