A common problem with constructing wetlands on abandoned mine sites is the lack of adequate soil needed to establish vegetation. One component of a full-scale passive treatment system, built at Jennings Environmental Education Center in Brady Township, Butler County, PA, addressed this issue through the development of a "field trial" to find an inexpensive alternative substrate for wetland plants. A simple soil substitute "recipe" was followed which called for the mixing of an inorganic material with a nutrient-rich organic material. The inorganic constituent used was silt-size pond cleanings from a sand and gravel operation. The organic material used was a composted product made from exceptional quality biosolids. Both components were obtained from local sources (less than 16 kilometers [12 miles] from the site) and mixed on site with a Caterpillar 943 track loader. The soil was used to construct a channel wetland 3 meters (10 feet) wide by 60 meters (190 feet) long. A seed mixture which contained 22 different wetland plant species was added to the substrate prior to directing the partially treated abandoned mine drainage into the wetland. After one year, the vegetation was studied to determine the percent cover and species composition in orderto document the effectiveness of this method of wetland construction. The preliminary results of this study indicate that this is an effective means to establish and sustain wetland vegetation. The addition of a fabricated substrate consisting of composted biosolids and silt can be a very effective method to establish dense and diverse vegetation in a constructed wetland.
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