Grant aims to help keep runoff out of Miller CreekWhen the land where Miller Hill Mall now sits was covered with trees and grass, rain and melting snow percolated slowly downhill toward the creek by the same name.
By: John Myers, Duluth News Tribune
When the land where Miller Hill Mall now sits was covered with trees and grass, rain and melting snow percolated slowly downhill toward the creek by the same name.
Now, the mall roof and its parking lots cover about 66 acres with an impenetrable, impervious shield of asphalt, concrete and rubber. With nowhere to soak in, rain gushes off in a torrent, often warmed by the black roofing material and blacktop.
That warmed water — along with salt, sand, trash and pollutants — gushes into Miller Creek, which meanders around the mall parking lot, just out of sight for most shoppers. And that runoff makes life unpleasant or impossible for native brook trout and the critters trout eat.
But a $186,000 grant from the Minnesota’s Clean Water Fund announced last week aims to help soften the impact of mall runoff. The grant to the South St. Louis Soil and Water Conservation District will pay for a comprehensive plan to manage and treat runoff at the Duluth mall.
The plan will guide “on-the-ground improvements around the mall to retrofit their parking lots and manage how stormwater travels over the property.”
So far, Simon Properties, which owns the mall, has agreed to allow the plan to be developed for its property, but hasn’t made any commitments to build specific improvements.
“We are extremely excited that the mall is willing to work on improving their property to help restore its namesake, Miller Creek,” said Kate Kubiak, conservation specialist for the South St. Louis Soil and Water Conservation District.
Miller Creek starts in wetlands near the Duluth International Airport and runs nine miles to the Duluth harbor. After decades of development in its watershed, the stream drew renewed attention in the 1990s from conservationists who wanted to keep it a viable trout stream. Several people worked together under the banner of the Miller Creek Task Force, and anglers, scientists, biologists and others worked to restore the stream to a healthier state.
Those efforts included planting hundreds of trees along its banks to shade and cool the water, and installation of sediment traps to catch grit that flows off parking lots along the river’s banks. Some businesses have installed underground rainwater basins to filter and cool rain that runs off parking lots.
The new mall plan will be developed over the next year by Barr Engineering, which developed a similar project at the Maplewood Mall in the Twin Cities, also owned by Simon. That project took several years and cost more than $6.4 million, with most of the money coming from grants through the local watershed district.
The project transformed not only the look of the Maplewood Mall and its parking lot, but also how water moved across the landscape there. When it was completed, the effort had added 55 rainwater gardens, 6,733 square feet of permeable pavers (water can soak through the cracks between the bricks,) a full mile of tree trenches that catch water soaked up in roots, 375 trees and a 5,700 gallon cistern that catches roof runoff.
The project’s pieces now combine to catch 20 million gallons of runoff every year, about 67 percent of the total that flows off the mall property.
Conservation officials hope the Duluth project won’t just help the nearby stream, but that the mall’s thousands of visitors will see the results, making the project an educational opportunity.
“A lot of this project will be trying to figure the possibilities of what might work and what’s possible at this specific site, and finding out exactly what the goals are. In this case, one of the goals is to get cooler water flowing into the creek,” said Erin Anderson Wenz, a senior water resources engineer for Barr. Anderson Wenz worked on the Maplewood Mall project and is working on the Miller Hill Mall project as well. “We’re really doing urban retrofitting here; trying to make things better while working within the existing development.”
The grant money for the Miller Hill Mall project came through the Minnesota Board of Water and Soil Resources and came out of the Clean Water, Land and Legacy fund that is stoked with a portion of the state’s sales tax dedicated to environmental and cultural resources.
Conservation officials hope that the fund also will support the actual construction of the mall project.
Kohls stretch to be “re-meandered”
The Conservation District also has been awarded a $154,000 Clean Water grant to help restore a section of Miller Creek near the Kohl’s store that was straightened many years ago.
The $154,000 Miller Creek Urban Trout Stream Restoration grant will allow the district, in cooperation with the city of Duluth and state agencies, to restore the original, curvy channel of the creek. The project also will restore trout habitat, lower water temperatures and slow the stream to reduce erosion.
Kubiak said design work is completed and actual field work should start soon.