North Texas Municipal Water District, 121 Regional Disposal Facility
Collin County, Texas

Overview
The North Texas Municipal Water District recently permitted the 121 Regional Disposal Facility (RDF) as a Type I municipal solid waste disposal facility through the Texas Commission on Environmental Quality (TCEQ). The 121 RDF permit application was determined Technically Complete on May 24, 2002. The permit was issued by the TCEQ on January 8, 2004. Biggs & Mathews and Alan Plummer Associates were contracted in February 2002 as the Project Team to begin providing professional engineering services for the Phase I Initial Site Entrance Facility Development construction of the 121 RDF. As the project progressed, our professional services were expanded to include the Phase II Initial Landfill Development construction. The professional engineering services provided have included permitting, engineering design, airspace calculations, and construction phase engineering services for each phase of development. Integral to the development of these projects is an ongoing comprehensive quality review and quality control program implemented by senior staff not engaged in the day-to-day design development. Planned meetings at strategic milestones maintained the owners participation in decision-making.

Phase I Site Entrance Facilities
The Project Team provided engineering design and construction phase services for the initial site entrance facilities at the 121 RDF. Alan Plummer Associates took the lead with the Phase I project. The site entrance facilities consist of perimeter berms, perimeter fencing, landscaping, site entrance road, gate house and scales, maintenance building, and citizens convenience center. The Project Team worked with North Texas Municipal Water District to define the specific design elements associated with the Phase I Site Entrance Facilities. The municipal solid waste permit along with specific owner direction and previous engineering expertise of the Project Team allowed the site entrance facilities to be planned, designed, and constructed consistent with the owners needs. The design approach was defined in a Design Basis Memorandum that identified each decision point to facilitate owner direction, prior to beginning the detailed design phase-Phase I Site Entrance Facility construction cost estimate was $5.1 million. The low bid was $4 million.

Phase II Initial Landfill Development Sector 1
Biggs and Mathews took the lead with the Phase II project to provide engineering design and construction phase services for the initial landfill development. The project included construction of an approximate 23-acre Subtitle D liner and leachate collection system, approximately 10,000 linear feet of landfill access road, approximately 2.6 million cubic yards of excavation, perimeter berms, perimeter drainage, surface detention facility, non-potable water supply well and storage tank, perimeter fencing, and perimeter signs. Kenneth Welch served as the project manager, with David Clark as the project design engineer and construction manager. During the design phase Biggs & Mathews prepared the landfill design components based on the landfill design included in the permit application and Site Development Plan. During the construction phase, Biggs & Mathews continues to coordinate with the TCEQ, the North Texas Municipal Water District and the contractors, conduct site visits, review submittals, issue change orders requested by the owner, resolve conflicts, and prepare construction reports. Biggs and Mathews also prepared several minor Permit Modifications that clarified some aspects of the Site Development Plan to facilitate construction that have been approved by TCEQ. The Phase II Initial Landfill Design construction cost estimate was $12.7 million. The low bid was $9.9 million.