Calvary Hill Case Study

St. Cloud, MN

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PROBLEM:

The City of St Cloud, MN was having issues stabilizing a slope and maintaining good vegetation. They were also looking to establish a vegetated emergency access road to a pump station. The slope was reshaped, and a retaining wall was installed to help mitigate some grade issues. They wanted to reinforce the slope in order that mowing equipment would not cause damage to the slope.

APPLICATION:

Landlok 300 was installed on the slope on July 8th, 2011, and was subject to a two-inch rain event two days after installation. The Turf Reinforcement Mat was infilled with Biotic Earth Black at a rate of 3500 lbs per acre, with Earthbound Scientific at a rate of 70 lbs per acre. The product was covered with Mat Fiber Plus at 2000 lbs per acre. The area to the right of the boulder wall is where the GrassPave2 product was installed. This product was filled with sand to allow greater infiltration of rainwater. This was covered with the same combination of Biotic Earth and Mat Fiber Plus as the Landlok 300.

IMMEDIATE SUCCESS:

By August 8th, the project was thickly vegetated, and had to be mowed down. By September 8th, there was significantly better vegetation where the Biotic Earth was sprayed compared to the existing vegetation.

Noah Czech, a Stormwater Compliance inspector for the city of St Cloud, discussed the project at the Minnesota Erosion Control Association show in March of 2012. He was very happy with the results, responding that the maintenance workers did not like the site because, "they have to mow it too often."

This project showed that the Biotic Earth Black and Mat Fiber Plus combination was an excellent alternative to Soil Infilling. The vegetation established quickly and was very dense.

SECOND YEAR SUCCESS:

We revisited the site on May 26th of 2012 to follow up on the installation. There were several interesting things to note:

On the portion of the job where soil had been hauled in to reshape the slope (where the TRM was installed) there were significant amounts of unwanted plants growing the first year. This appears to be the results of importing a seed bank with the soil was imported. If you notice the area to the right of the picture above, you will see very little weeds growing. The area had been seeded with a turf mix. A herbicide was applied to deal with the unwanted plants on the slope. The site is now covered with a thick stand of turf grasses.

Have questions? Contact Mark directly:

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