The City of Sheridan’s participation in the Wyoming Department of Environmental Quality’s (WDEQ) Landfill Remediation Program (LRP) offers a comprehensive case study in remediating active and legacy unlined municipal solid waste landfills. Initially constructed without liners or leachate controls, the old landfill and existing landfill presented significant groundwater contamination and operational challenges. Key lessons from the project highlight the importance of thorough site characterization, particularly in historically filled sites with limited documentation.

High-resolution site characterization borings, test pits, and piezometer installations proved essential in defining waste boundaries and groundwater impacts, especially where waste was saturated and intermingled with natural drainage features. However, site characterization only provides so much preliminary data and cannot replace appropriate construction contingency planning, close communications among all parties, and full-time project construction oversight. Financial planning and construction cost mitigation is pivotal; the LRP’s 75% cost-reimbursement structure supported major capital expenditures such as waste excavation and lined cell (Cell 10) construction. These corrective measures addressed environmental risks and maintained operational continuity — often overlooked in remediation projects.

Integrating future planning into design (e.g., Cell 10’s underdrain and liner tie-ins) optimized long-term site management and regulatory compliance. Close coordination and frequent communication among the major stakeholders — including WDEQ, the City, and consultants — enabled flexible decision-making, such as adjusting designs accommodate unforeseen field conditions or cost constraints. The need for adaptive strategies was particularly evident in managing friable asbestos and modifying designs near critical but aging and poorly documented facility infrastructure.

Discover how Sheridan’s program underscores the value of integrated technical, financial, and regulatory planning and coordination in landfill remediation.