City of Pampa, Pampa Landfill
Gray County, Texas

Project Type: Subtitle D Alternate Cells, Site Improvement

Overview
Biggs & Mathews has provided professional engineering and hydrogeologic services to the City of Pampa on the Pampa Landfill since 2000. The Biggs & Mathews senior project professionals began providing professional services to the City of Pampa, while at another firm, in 1992. The professional services provided have included siting, permitting, engineering design, environmental monitoring, hydrogeologic characterizations, airspace optimization, construction documents, construction phase engineering services, and construction quality assurance for multiple projects since 1992. The success of these projects are founded on the inclusion of the City in the decision process including construction budgets, and the application of our quality review and quality control procedures. The continued professional relationship to the City of Pampa from the project professionals demonstrates a professional commitment to the long-term success of the City of Pampa municipal solid waste disposal program.

Municipal Solid Waste Permitting
The Biggs & Mathews project team served as engineer of record, geologist of record, and project geotechnical engineers during the site investigations, environmental analysis, subsurface characterization, and engineering design to support the Greenfield, Type I municipal solid waste disposal facility permit application. The City of Pampa Landfill was permitted to serve as a regional landfill for seven counties and numerous communities in the Panhandle region of Texas. The City of Pampa Landfill is a 146-acre landfill designed to provide in excess of 50-years of disposal capacity for this region. The City received its Type I municipal solid disposal facility permit on December 29, 1995.

Geology and Hydrogeology
A complex geologic and hydrogeologic characterization of the Pampa site subsurface was completed by Biggs and Mathews geologists. Identification and correlation of subsurface strata and detailed characterization of lithologic materials and completed for the solid waste permit application. Based on calculated hydraulic conductivities and groundwater flow directions and rates, a contaminant pathway analysis was completed and the dual zone groundwater monitoring system was designed. A groundwater sampling and analysis plan (GWSAP) was prepared and approved. Biggs and Mathews installed the first phase of the groundwater monitoring system.

In addition, a comprehensive fault and seismicity analysis was prepared by Biggs and Mathews geologists. Based on this analysis, the Subtitle D location restriction certification for fault areas and seismic impact areas was prepared for the site.

Construction Documents
Biggs & Mathews project professionals provided engineering design, construction phase services, and construction quality assurance for the initial Subtitle D cell, site entrance road, perimeter berms, perimeter drainage facilities, installation of landfill gas monitoring probes and groundwater monitoring wells, and various site improvements at the Pampa Landfill. The initial Subtitle D cell was an approximate 5-acre cell with liner and leachate collection system, a leachate pumping and transfer system, site entrance road, perimeter berms, drainage, and other miscellaneous improvements to the landfill.

Since 2000, Biggs & Mathews has provided engineering design, construction phase services, construction quality assurance services, air quality permitting, municipal solid waste permitting, and airspace maximization studies for subsequent landfill cells and other site improvements at the Pampa Landfill. Biggs and Mathews is responsible for all professional services related to the construction of Cell 2 and Cell 3. These projects consisted of about 10-acres of lined area with the total construction cost of approximately $2,000,000. These projects included the construction of a liner and leachate collection system, perimeter berm construction, and perimeter drainage systems. The engineering design included evaluation of excavation and earthfill requirements and development of a soil management plan to maximize use of soils on the newly permitted landfill as well as an older permitted landfill that remains open.

Construction Management
During the construction phase Biggs & Mathews provided advertisement and award phase including evaluation of construction bids and recommendation of award. During the construction phase Biggs & Mathews provided record surveying services, coordinated with the TCEQ, the City and the contractors, reviewed submittals, issued change orders requested by the City, resolved conflicts prepared the final construction reports and administered the construction contracts. Biggs & Mathews worked with the City to incorporate City staff during the excavation observation of these projects. Once liner construction began, all on-site observation was conducted by Biggs & Mathews