Fridley, Columbia Heights replace collapsed area of runoff pipe

Fridley and Columbia Heights recently finished their largest storm-water project of the year: They replaced a 60-foot section of pipe that collapsed this fall with its surrounding bank into a catch basin by the Mississippi River, officials said.

The neighboring cities spent nearly $117,000 to replace the 8-foot-diameter pipe and restore the bank around it just north of the Minneapolis water treatment plant in Anoka County's Riverfront Regional Park in Fridley.

The pipe and bank collapse was discovered in September, a contractor was chosen in November and the work was largely completed by mid-December, said Fridley Public Works Director Jim Kosluchar. He said the corrugated metal pipe was almost 45 years old and had rusted out from the river level rising and falling around the pipe outfall into a catch basin inlet off the river. Kosluchar said cold weather hindered the project.

"The timing was a big deal," said Kevin Hansen, public works director for Columbia Heights. "We wanted to make sure the pipe and slope were in place for spring when the snow melts and spring rains come."

The pipe handles about 60 percent of storm runoff in Columbia Heights, which has paid about 68 percent of the cost, Hansen said. The state Department of Transportation is paying about 10 percent of the repair cost, and Fridley is paying the remainder under an agreement made when the corrugated pipe was installed in 1965.

The project took about three weeks. A wood fiber blanket was laid across the rebuilt slope, roughly 100 by 40 feet in area and 30 feet deep, Hansen said. More grass seeding and slope planting will be completed in the spring.

Hansen said the main improvement is the reinforced concrete pipe used to replace the collapsed section as well as an additional 60 feet of pipe extending into Riverfront Park to a connection with another concrete pipe. The new pipe should last 60 to 100 years, Hansen said.

But the two cities are reviewing and expect to modify the agreement and their cost sharing in light of runoff changes caused by residential and commercial development since 1945, Kosluchar said. He estimated that the pipe handles 10 to 15 percent of Fridley's storm water.

Fridley inspected the work, which was done by G.L. Contracting of Medina. The company brought in large excavating backhoe buckets that dug the collapsed bank material out of the catch basin, let it dry and packed it back into the hole in the slope, Kosluchar said.