Trihydro is contracted with the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation and Water Quality, Mines and Minerals Bureau (Bureau) to develop reclamation plans for abandoned strip mines located in southcentral Iowa. To date, Trihydro has been tasked with developing reclamation designs for four sites identified as the Teach AML Reclamation Site, Vander Beek-Langstraat AML Reclamation Site, Rowley AML Reclamation Site, and the Waechter AML Reclamation site. The sites are former coal strip mines totaling 194 acres and consisting of polluted waters, water-inundated pits, vertical highwalls, large spoil/overburden piles, and clogged streams.
At each of the sites, Trihydro performed site investigations to document and assess the conditions and hazards associated with site features. Feature mapping, aerial photos, LiDAR topographic mapping, ground-based topographic mapping,
and digital photos were collected during the field investigations and compiled into a web-based project management portal (Trihydro’s Project Direct©) that includes a site-specific GIS application.
Trihydro developed conceptual, preliminary, and final reclamation plans for review by the Bureau and landowners. To aid in developing the site plans, natural resource surveys and a geotechnical investigation (at the Teach site only) were performed to identify potential “Waters of the U.S.”, wetland areas, water quality, depth of spoil material, and surface soil composition. The investigations included wetland delineations, geotechnical drilling, and surface water sampling and analysis.
The final reclamation designs for the sites incorporate geomorphically stable design concepts using Carlson’s Natural Regrade software. The Teach site was Iowa's first AML site to be designed completely using the geomorphic grading approach.
Trihydro prepared final construction plans and specifications, developed construction estimates, prepared bid documents, conducted the pre-bid meeting and tour, and assisted the Bureau with bid adjudication for three of the four projects.
Trihydro and the Bureau coordinated with the landowners and the U.S. Army Corps of Engineers (USACE) to develop designs that provided for the abatement of the polluted drainages from the areas as well as eliminated the recognized public safety and other environmental concerns present at the sites, while mitigating disturbances to wetlands and Waters of the U.S. Trihydro also provided construction management and performed part-time, on-site construction monitoring during construction of the projects.
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