- Data review
- Geotechnical analyses and review
- Alternatives evaluation
- Design concepts
- Owner’s representative during construction
- Construction administration services
The Lupton Lakes Reservoir site consists of a series of gravel pits created from sand and aggregate mining activities. Denver Water subsequently acquired the gravel pit complex with the intention of converting it into lined water storage reservoirs. At the time the gravel pits were acquired, it was lacking all of the major components required for use as a water storage reservoir including a groundwater liner, hydraulic infrastructure, stable reclamation slopes, and a spillway.
RJH performed an alternatives analysis to evaluate potential seepage barrier options to create lined, below-ground water storage reservoirs. Four compacted clay liner alternatives and one barrier wall alternative were evaluated. RJH evaluated barrier alternatives for technical and economic feasibility, and led a workshop with Denver Water and other consultants to identify a preferred alternative. The selected alternative consisted of constructing a compacted clay liner on top of the reclamation slopes. This approach resulted in the least disturbance to on-going mining operations and was cost competitive with the other barrier concepts. RJH also developed concepts for reservoir appurtenances such as spillways, interconnects, inlets and discharge facilities, groundwater drains, etc.
Recommendations provided by RJH were used to advance the project into the 30-percent design phase. Based on RJH’s recommended concept, Denver Water elected to develop the reservoirs using a design-build approach during which the lining method was changed to a barrier wall concept. RJH served as Denver Water’s representative throughout the first phase of the design-build while reviewing investigations, analyses, drawings, and specifications. RJH also provided full-time on-site construction engineering support throughout the barrier wall and slope reconstruction. This full-time support helped to mitigate and avoid construction claims by the design-build team.