OAK PARK HEIGHTS — The Oak Park Heights City Council and state Department of Transportation reached an agreement Tuesday on the cost of upsizing water mains and routing of those mains as part of the St. Croix Crossing project.
The council first approved an agreement with MnDOT for the city to pay $11.50 per foot to upsize city water mains from 8-inch to 12-inch diameter pipe. A short time later, council approved a route placing the upsized water main in MnDOT right-of-way.
The $11.50-per-linear-foot cost of the upsized water main pipe was reached by the city and MnDOT after the state agency initially suggested a $12- to $14-per-foot costs and the city estimated $8- to $10-per-foot.
City Engineer Chris Long said in a letter to the council dated Monday that at $11.50 per foot, the cost for the upsized water main, valves and fittings were be slightly more than $145,000.
“The total amount of $145,243 is an appropriate estimate for the water main upsizing costs not originally accounted for during the 40 percent design,” Long said.
City Administrator Eric Johnson said in a memo to the council the cost of water main upsizing was anticipated since the city requested the upsizing, which he added was called for in the city’s 2008 water distribution plan.
“While moving from an 8-inch to a 12-inch line was accounted for in the bidding specifications, the dollars to pay for it must be reallocated, being that the city is responsible for the upsizing costs,” he said.
Johnson said MnDOT sought council approval of a water line route after it was discovered that one proposed route east from Phil’s Tara Hideaway placed the line over the clay cap covering Xcel Energy’s fly ash site.
Jason Petersen, an engineer with Stantec Consulting Services, Inc., said the Minnesota Pollution Control Agency expressed concern about how possible water main leaks might affect the clay cap.
“A monitoring schedule would have been needed to be developed, and the city could still be held liable for damage to the cap that may have occurred in the event of a water main leak or break,” Petersen said in a letter to the council.
Petersen offered three alternative routes he called options X,Y and Z
Option X took the line south around the clay cap from the south frontage road near Club Tara south along the west edge of Xcel’s property, east along the north edge of city park property, then north between Peller and Penrose avenues to tie in on 59th Avenue
Option Y installs a new water main south on Osgood Avenue, east along 58th Street, across the north edge of a city park, then north between Peller and Penrose avenues, tying in on 59th Avenue.
Option Z has the main crossing to the north side of Minnesota 36, then east in MnDOT ROW, then south crossing the new ramps and highway and tying in near Beach Road and 59th Avenue.
Petersen noted that if the third option was selected, casing pipes would be required for water mains under ramps and highways.
But Petersen said advantages to the third option include avoiding the clay cap, eliminating disruptions to city streets and services, installing the mains in MnDOT ROW and minimizing added lengths of water main.
“One possible additional benefit is that this water line crossing would be paid for by MnDOT, and not a ‘betterment’ to the city, saving $75,000 to $100,000, plus or minus,” Johnson added.
Petersen said MnDOT, Ames-Lunda, MPCA and city representatives met June 20 to discuss the options.
“Option Z was selected as the favored choice,” he said. “We feel that Option Z will provide the city with an alternative that meets the needs for water distribution system. Similar to other options, Option Z does have some maintenance concerns, but we feel that it is an acceptable alternative.”
“What MnDOT is looking for is if the city is comfortable with the route,” Johnson added.
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