Onondaga County Water Authority (OCWA)
Otisco Lake, Onondaga County, NY
The Onondaga County Water Authority (OCWA) utilizes raw water sourced from Otisco Lake to treat, store, and distribute finished water to its customers in Central New York. The Authority commissioned a project to improve raw water system hydraulics by replacing the 60-year-old intake pipe located at the Otisco Lake intake site. It was determined that the improvements could be achieved by utilizing the same size pipe and a new alignment to a more hydraulically beneficial route. This approach allows OCWA to maximize the gravity withdrawal of water from Otisco Lake. By increasing the gravity withdrawal of water from the current maximum of 18-19 million gallons per day (mgd) up to 20 mgd, these improvements resulted in an energy savings by reducing the required withdrawal from the Lake Ontario supply, which is a pumped system. This energy savings will allow for a desirable simple payback period, of 5-10 year based on an operating cost impact analysis.
EDR provided the engineering services to perform the hydraulic and pipe modeling necessary to confirm the pipe routing and design elements needed to achieve maximum raw water withdrawal. Evaluations of differing pipe thickness classes, trench type, and trench excavation support systems were completed based on the excavation depths and high groundwater conditions. The piping layout was developed to meet Department of Heath requirements and in close collaboration with OCWA to maintain raw water flow during construction and align with their short- and long-term operational needs.