A pre-fabricated, high-density, polyethylene (HDPE) liner, or Hypalon geomembrane, was installed as part of the upgrade to the 69-million-gallon Pond 3 storage reservoir. Pond 3 is approximately 9.7 acres in plan area and is located along the southern portion of the Colfax Waste Water Treatment Plant. It consists of an earth fill dam, spillway, outlet piping, and overflow alarm level device.
H&K performed a limited subsurface investigation at the northeast section of Pond 3 that included observation, documentation, and evaluation of the seepage occurring at the site. The investigation involved the upper 10 feet of soil. H&K prepared a limited-scope geotechnical report and provided design recommendations for subdrains.
H&K also provided one full-time engineering technician during construction. Scope of services included:
- Continuous field moisture/density testing during construction of the embankment fills.
- Periodic field moisture/density testing during construction of the 1:12 access ramp, subgrade for the perimeter access road, and subgrade for the liner.
- Laboratory testing to support the materials testing being completed in the field.
- Preparation of field and/or laboratory reports detailing the results of testing performed.