In the spring of 2011, officials at the Indiana Veterans Home in Lafayette, IN decided to repair a severe slope failure that had occurred on the property. The failure left them with a 1.8: 1 slope to repair. Lawson Fisher, the engineering firm designing the project contacted D2 Land and Water Resources for suggestions on how to vegetate and stabilize the site. The slopes were so severe that there were safety concerns with placing and keeping topsoil on the slope.
D2 recommended utilizing Biotic Earth Black, a hydraulic growth medium, applied at a rate of 4,000 lbs. per acre, as well as Earthbound Scientific at a rate of 175 lbs. per acre. Biotic Earth Black was applied over the existing subsoil along with a custom native seed mix. Biotic Earth Black is a proprietary blend of rich organics, plant fibers, micro nutrients, humates and fungal mycorrhizae which will revitalize poor subsoil and enable vegetation establishment without importing topsoil. The contractor then covered the material with a Turf Reinforcement Mat (TRM) that contained a Coconut Fiber medium. The TRM provided immediate protection from the erosive forces that could affect the Biotic Earth Black. It also helps to regulate temperature and maintain the moisture levels in the germination zone. The TRM was anchored to the slope using 3’ lengths of rebar. The project was installed in early June of 2011.
By the fall of 2011, the native plants which can take up to 3 years to fully establish, had begun to fill in and stabilize the slope. Germination rates of the various plants were observed to be higher than what was normally expected using that seed mix.
Since the fall of 2012, the site is covered in dense vegetation, which combined with the TRM, protects the slope from the threat of erosion and slope failure.
Biotic Earth products can be used in conjunction with other erosion control materials to provide a safe, natural, cost-effective alternative to traditional methods of slope stabilization. This case study also shows that in areas where topsoil is not practical a soil amending approach is a reasonable solution.