Pioneer completed the 5-year inspections for both Basin Creek #1 and #2 high hazard dams located in Butte-Silver Bow County. Upon completing the inspections, the existing conditions of both dams were assessed to determine if there were any cracking, deterioration, seepage, leakage, or maintenance concerns. An inspection summary report was prepared documenting the inspection results and providing our recommendations. Our design team assisted the dam owners with renewal of the Operating Permits for both dams.
Pioneer’s design team prepared a Department of Natural Resources and Conservation (DNRC) Renewable Resource Grant application in 2000 for the rehabilitation of the existing high hazard Basin Creek Dam #1 concrete spillway. The existing concrete spillway for Basin Creek Dam #1 was in dire need of repair, and was not in compliance with the new Dam Safety Act requirements. For these reasons, our design team was tasked by Butte-Silver Bow County to prepare the grant application to acquire funding for rehabilitating the concrete spillway.
Pioneer completed the required Uniform Preliminary Engineering Analysis, Uniform Environmental Checklist, Conceptual Design, Construction Cost Estimate, and Construction Schedule, as required in the grant applications. In order to complete these items, our design team completed a detailed hydraulic, hydrologic, and geotechnical analysis of Basin Creek Dam #1. The hydrologic analysis determined the spillway dimensions and required freeboard for the dam. The geotechnical analysis included a detailed embankment stability analysis to determine the dam’s ability to be overtopped.
Based on the results of these analyses, we prepared alternatives for the spillway rehabilitation. Each alternative would bring the dam into compliance with the Dam Safety Act requirements for high hazard dams. We prepared detailed construction cost estimates for each alternative. The selection process that determines the best alternative was a comparative analysis of the technical feasibility, financial feasibility, and public comment on each alternative.