SIOUX FALLS, S.D. (KELO) — Commuters who use Cliff Avenue between 57th and 49th Street will need to take a new route at the end of this month.

The street section from 56th to near Tomar Road will be closed from roughly May 29 to Aug. 17, said John Osman, a project engineer with the City of Sioux Falls.

Cliff Avenue must be open again before school starts, Osman said. The avenue is a main route from the south to Lincoln High School.

Residents who live on Tomar Road will still have access to Cliff Avenue and the 49th Street intersection should be open at Cliff Avenue, said Ross Kutchta, an engineer with Stockwell Engineers said. Stockwell is working on the project.

A map of the Cliff Avenue project. Graphic from the City of Sioux Falls website.

The closure is part of the second phase of the construction to widen that section of Cliff Avenue to add another driving lane. When the project is completed there will be two northbound and two southbound driving lines along with turning lanes at several instersections.

Traffic will be directed to a detour on Minnesota Avenue, Osman said.

The first phase starts May 11 and will reduce traffic to one lane each northbound and southbound.

Cliff Avenue will be widened on the east and west sides. Trees will be removed on each side of the avenue to make room for a wider street.

The trees are ash trees and must be removed during the specified times to avoid the spread of emerald ash borer, Osman said.

“We will be starting on the east side and working our way west,” Osman said.

Engineer Brad Ludens said in a past KELOLAND News story that the sidewalks will be removed on the east side of Cliff Avenue will be next to the street. The reconstructed sidewalks will be at the avenue curb, he said.

That would be similar to a section of Cliff Avenue from 33rd Street to 26th Street.

The section of Cliff Avenue from 49th to 57th includes a narrow shoulder with no sidewalk next to a slope down to a creek area.

The contractor, T & R Contracting of Sioux Falls, will need to build a road and shoulder base from the ground up to allow for a widened street.

“We will be widening it out quite a bit to the west (too),” Osman said. “That is the most extensive part of the project as far as work is concerned.”

The west side shoulder of a section of Cliff Avenue between 49th Street and 56th Street. A contractor will need to build a base on this slope so there is space to widen the avenue.

Adam Dalseide, the project manager for T & R Contracting said a house that sits below Cliff Avenue, to the south of Tomar Road, will be removed for the construction project.

Fill will be added to that space so the street can be widened. The contractor has to create the space for a wider street on the west side.

Osman described the adding of fill as a stair-step type project.

“We (will) be adding dirt and packing the dirt as we go to the (top),” Dalseide said.

“It is a tight spot,” Dalseide said of the work area which will be along a slope that continues to what is creek bottom.

Osman said Cliff Avenue will be closed to allow for that work and to help make sure the project is completed before school starts.

A public open house for the $327 million project is set for 5 to 6 p.m. on Monday, May 9 at the downtown City Center Building.