A corroding sewage line on the north side of Lake Calhoun has to go, and the work needed to replace it over the next three summers will re-route traffic, tear up segments of the Midtown Greenway and may even close the channel that connects Lake Calhoun with Lake of the Isles.
If not addressed in a timely manner, the 40-year-old concrete line is in jeopardy of springing a leak that could send raw sewage into back yards or parks, according to officials from the Metropolitan Council, the agency in charge of metro wastewater treatment.
The new line would run northeast on Sunset Boulevard, cross the Kenilworth Trail on 28th Street before zigzagging to the Midtown Greenway Trail and following it to Irving Avenue.
Neighbors are keeping a watchful eye on the process, but say that so far they’ve been pleased with how Metropolitan Council engineer Adam Gordon has listened to their demands and planned a route that will disrupt the neighborhood and summer activities as little as possible.
“The crux of the issue is we have to replace sewer lines,” said Anita Tabb, the Minneapolis Park and Recreation Board Commissioner that represents the district where the line will go. “It’s not like we can do without them. It’s an issue that has to be addressed. We have to get those replaced. So the issue is where is the best location to dig up and put in the new ones.”
Tabb said she’s been pleased by how much the Metropolitan Council has worked with the Park Board on the plan over the past year to protect park amenities.
Still, installing twin 24-inch sewage lines through one of the most densely populated and highly recreated areas of the Twin Cities won’t come without challenges.
The Metropolitan Council plans to phase construction out over three years. The first segment —along the Greenway between Dean Parkway and Knox Avenue — will be completed in 2011, if plans go accordingly. Crews are tentatively expected to start working on the project this summer.
The stretch to the west of Dean Parkway will be completed in 2012. Finally, a relining of the pipe from Knox to Irving and north to 27th Street will be completed in 2013.
The Park Board, the Hennepin County Regional Rail Authority and private property owners will have to agree to give the Metropolitan Council easements to lay the pipe.
The total cost of the project, including work that was completed in Hopkins and St. Louis Park in previous years, will cost $64 million and be paid for by a $1.35 per year sewage rate increase per household in the entire metro area as well as a fee increase for new homes that connect to the metro sewer system.
Bicyclists, runners and skaters who use the Midtown Greenway can expect to reach all of their destinations during construction. At some places where crews need to dig under the trail, they will pave a temporary asphalt path around the area, Gordon said.
Greenway users will not, for two months this summer, be able to enter and exit the trail onto Dean Parkway. Crews will need to dig around the ramp there to properly bury the pipe. Gordon said he is asking the Hennepin County Regional Rail Authority about making a temporary entrance one block east at Thomas Avenue.
Without the Dean Parkway ramp, bicyclists will have to go west to Whole Foods or east to the Lagoon to get on or off the trail.
Boaters who like to paddle between Lake Calhoun and Lake of the Isles may have to portage between the two lakes next fall.
The new sewage line must be buried below the channel that connects the two lengths. That will require crews to dredge the channel.
Gordon said he hopes the dredging and other work can be done while keeping the channel open to boats. But environmental issues may prevent that, and in that case crews would have to clear a path on land for boaters to portage.
Work on the channel will begin after Labor Day so as to avoid disruption during the busiest months for boat traffic.
Traffic will mostly be unaffected until 2012. That’s when crews will need to install the new sewage lines below city streets in the Cedar-Isles-Dean neighborhood.
Gordon said the crews will work in one-block increments that will require one side of Sunset Parkway to be closed to traffic for approximately one month each.
The Cedar-Isles-Dean Neighborhood Association is working with the Met Council and the city to have sidewalks constructed as part of the project along Sunset between Chowen and Depot, where there are none, said board member Ed Bell, who lives at the Sunset and Depot intersection.
In 2013, crews will be re-lining the existing pipes from on Irving Avenue from the Greenway to 27th Street and then for one block on 27th Street. This will require a temporary sewage line to be laid across intersections, which Gordon says will have to be buried to allow for traffic to cross.
Originally, the Met Council planned to install the new line through Dean Park and along 28th near the soccer fields.
But then Don Willeke, a 40-year resident of the neighborhood and a tree enthusiast, did a walk-through of the route with Gordon. They determined that using that route would endanger many rare trees in Dean Park as well as a group of 100-year-old oak trees just west of the soccer field by Lake of the Isles.
Gordon agreed to run the route south, which Willeke said will save those trees and instead sacrifice less valuable trees like American ash, cottonwoods and American elms.
The Metropolitan Council had alternative options for the sewage line. One option was to re-route the line down near Shakopee, completely avoiding Minneapolis, but Gordon said that would cost twice as much as the current plan.
The Metropolitan Council plans to hold public meetings later this winter or this spring.