Date
Monday, July 28, 2025
Time
10:30 AM - 11:00 AM
Location Name
Room 301B
Name
Double Trouble to Single Solution "“Replacing Existing Intake and Transfer PS with One Intake PS
Track
Modeling/Planning
Description

The City of Pigeon Forge hired LDA Engineering for the design of a new raw water intake pump station at Douglas Lake and new transmission water main to increase capacity to meet the growing demands of Pigeon Forge and surrounding municipalities. Raw water is supplied to the City of Pigeon Forge primarily by the existing intake and pumping facilities located on Douglas Lake. The existing facilities consist of two pump stations, namely the intake pump station and the transfer pump station, that pump a maximum of 7 MGD to the plant through a 24-inch DIP transmission main that was installed in the early 2000’s. The existing conveyance system is generally limited to approximately 7 MGD with the installed pumps, although the intake is permitted for 10 MGD. The City of Pigeon Forge has experienced operational issues with the intake pump station in recent years. The submersible turbine pumps at the intake pump station are oriented on a 22.5-degree angle. Given this orientation and the valve structure layout, removing and maintaining the existing pumps is a very tedious and difficult process. In addition, the City has experienced multiple pump failures in recent years including pumps needing to be replaced within three years. The issues that have been experienced have required significant financial and man-power investment to keep the system operational. To evaluate the existing system and determine the best path forward, LDA Engineering partnered with CDM Smith. The team developed a computerized hydraulic water model of the existing system and proposed alternatives. As-builts of the existing transmission main and profiles of the anticipated alignment were used in the model. The model was utilized to analyze operational scenarios to determine the optimal solution. The water model was utilized to identify the controlling high points in the existing 24-inch transmission main and the proposed 24-inch transmission main. Key parameters such as surge were evaluated to ensure the design was acceptable. In addition, the model was utilized to evaluate the feasibility of replacing the existing intake and the existing transfer pump station with one pump station. The model confirmed that the proposed intake pump station could be equipped with three (3) 600 HP pumps that supply water at 4000 GPM at 400 TH. This pump sizing would remove the need for the transfer station. By consolidating into one pump station, Pigeon Forge will have less pumps to maintain and have less operational costs. The project is being delivered as a Construction Manager at Risk (CMAR). The construction manager is being procured, and construction is expected to begin in summer of 2025.