AWWA DSS71283

North Carolina experienced record drought in 2007, especially the Triangle area in the central part of the state. The drought caused extremely low water levels in the reservoirs that supply drinking water to the cities of Raleigh and Durham, prompting them to look to their neighbors for emergency supplies. The Town of Cary, a neighboring water system which is supplied by Jordan Lake, had sufficient supply capacity to meet its needs and to supplement Raleigh and Durham, primarily in the winter when demands were lower. This paper describes the hydraulic modeling that determined the maximum amount of water that Cary could supply to Raleigh and Durham on a sustained basis. The project identified limitations imposed by plant capacity, pump sizes and the capacity of the pipe systems on either side of existing and potential interconnections. The study involved combining three large hydraulic models and simulating flow between systems for extended periods. The combined model predicted flow rates, pressures and tank performance. The model investigated various scenarios aimed at maximizing flow through interconnections given pressure zone configurations and other unique features of each distribution system. Includes table.