A proposed $7.5 million restoration of Minnehaha Park in Minneapolis, aimed at reversing damage from erosion, is set to begin this year along Minnehaha Creek in the valley downstream from Minnehaha Falls.

A key part of the project is to secure state and federal money to renew the historic stone walls that define the creek channel and anchor popular trails near the 53-foot-tall cascade, which is the landmark of the 193-acre park off Hwy. 55 in south Minneapolis.

Victim of too much water

Built in the 1930s by the Works Progress Administration (WPA), the walls were weakened by high-water erosion during a record 4-inch downpour in October 2005.

Since then, one 30-foot chunk of a wall has lain collapsed in the creekbed. Officials say the walls still standing defy gravity and could go in the next flood.

"The walls are eroding from underneath," said Aaron Snyder of the U.S. Army Corps of Engineers. "Eventually, enough erosion under the walls will cause them to fall down.''

Finding the money to fix the walls is a priority, said Judd Rietkerk, director of planning and project management for the Minneapolis Park Board. "You ... look at them right now and you might say, 'Well, I wonder what is holding them up?'''

Erosion damage to the walls and the creek shoreline after the 2005 storm prompted the Minnehaha Creek Watershed District to team up with the Park Board to protect the park. The Minnesota Veterans Home, which overlooks the creek near its junction with the Mississippi River, and the Army Corps of Engineers also have joined the effort.

The goal is to renew the walls, anchor shoreline and sloping bluffs with native plants and rain gardens, and build new trails to stop erosion caused by walking and climbing, said Mike Wyatt, planner for the watershed district.

Where the money will go

This year, the district plans to spend about $1.7 million to begin the repairs by building a rain garden to reduce storm-water runoff from the Veterans Home into the creek, and by planting native vegetation to stabilize the creek bank in front of the home.

While doing that, the district is seeking at least $1 million from the federal government to save the WPA walls and another $5.3 million from the state to pay for 23 separate improvement projects involving trails, slopes and stream banks, and other needs at the park.

Of all the stone WPA structures built in the park -- including bridges, steps and creek walls -- the walls are disintegrating fastest, said Deborah Morse-Kahn, director of Regional Research Associates.

The Army Corps is studying ways to shore them up with concrete or other lasting materials, Snyder said. He could not say when the wall work would begin, but he said the Corps will start as soon as federal funding can be obtained -- possibly this year.

Corps engineers think they can return the walls to their original function of stabilizing the stream banks to keep the creek in its current location.

If the walls fall, "the creek will do whatever it wants to do as far as eroding the bluffs,'' Rietkerk said. If erosion continues, "soon you don't have any place for the trails to be.''

Without trails, the creek gorge could be viewed only from the top, Rietkerk said.

"A lot of what is at stake is the recreational ability to go down there and explore. Otherwise, you could say so what if the creek takes down some trees and the banks collapse,'' Rietkerk said.

The $5.3 million request from the state's 2008 bonding program must compete with nearly $4 billion in other funding requests from across the state.

The Senate bonding committee toured the park in the fall and did not rule out the project. But it wants to see where the project ranks among other Minneapolis priorities, said Sen. Keith Langseth, DFL-Glyndon, who chairs the committee. He said the state is likely to issue about $1 billion in bonds.

Previous improvements in Minnehaha Park during the early 1990s included a $5 million to $6 million reworking of park roads and reconstruction of the concession stand, Rietkerk said.

Laurie Blake • 612-673-1711