TFG contracted with NGPC in 2013 for a comprehensive rehabilitation design project at Conestoga Reservoir, Lancaster County. Conestoga Reservoir is a USACE facility and NGPC has fisheries, wildlife and park area management responsibilities. The overall objective of the project was to address the significantly degraded water quality and aquatic habitat conditions that have been prevalent at Conestoga Reservoir for several years. This shallow, well-mixed reservoir can exhibit short-term thermal stratification during the early summer months.
The reservoir has experienced blooms of blue-green algae, which have produced toxins in high enough concentrations to warrant beach postings. The most severe blooms have occurred during extended dry periods. A number of bays have silted in, little or no stands of rooted aquatic vegetation are present, the fish community is out of balance and incapable of sustaining a quality recreational fishery and overall fishing access has become limited.
The design plan addressed the reservoir problems in multiple phases:
- Phase I, completed in 2015, included necessary modifications to the existing outlet structure that will improve functionality and allow for more flexibility in seasonal and long-term water level management. The design process included quality control measures.
- Phase II, completed in 2019, included a comprehensive reservoir rehabilitation project. Two of the project priorities include large scale sediment removal of deposited sediment and construction of sediment control structure. In-stream hydraulic control structures induce sedimentation in off-channel wetland cells and in-line sediment basin. Haul roads and spoil sites were managed to optimize excavation and removal of sediment deposits from the lake bottom. Additional typical components of the rehabilitation project include the construction of breakwaters and additional shoreline protection features, selective excavation and basin sculpting near the boat launch area, improved boat launch facilities, angler access improvements, and construction of fish habitat/​attractor features.