Warren County District Landfill Partial Closure

Hatch Mott MacDonald was retained by the Pollution Control Financing Authority of Warren County (PCFAWC) to design a partial closure for the Warren County District Landfill in White Township, New Jersey. The project involved the capping of a 20 acre portion of the sideslope of the currently operational landfill.

The design incorporated a layered cap cosisting of a sand gas drainage layer, a 40 mil textured HDPE geomembrane, a drainage layer that consisted of a 12 in sand layer underlain by a bi-planar geonet geocomposite, a 12 in soil fill layer and a 12 in topsoil layer. The design was complicated by the fact that the landfill will continue to operate and additional lifts of waste will be placed at elevations higher than the upper limit of the capped area. Therefore, the design had to accommodate future conditions that would prevail when the site was completely closed.

In addition, as the landfill continued to operate during the construction of the partial closure, the design of the stormwater management system had to accommodate the separation of the contact stormwater from the operational area of the landfill. 

HMM performed construction management services on the project, which included shop drawing review, construction oversight, quality control on all cap elements, contractor invoice prosessing, design interpretations, punchlist, and as-built documentation.