Partial Recovery of Water Supply in Disaster Using Pressure-Dependent Analysis

Disaster to water supply systems can occur due to failure of its raw water resource. Providing water supply in crisis period is a daunting task for water supply authorities. Flood or earthquake can damage a storage dam that supplies drinking water to a city. If one of the raw water resources, which supplies water to a city, is damaged in the disaster, the system must ensure that it receives water from the alternate raw water resource to maintain continuous water supply for the minimum life sustenance (say, 70 Liters Per Capita per Day, LPCD) by introducing an interlinking pipeline from the adjoining city’s water supply. In conventional water network solving, demand is fixed. It is presumed that the demand is always satisfied at the nodes and the nodal pressures and pipe flows are determined with respect to this known demand. All the traditional network solving algorithms are based on this assumption. When a major raw water resource supplying water to a city fails, pressure-deficient conditions are formed in the distribution system and alternative arrangement must be made to recover water supply. In such situation, the traditional methods are not enough to describe the behavior of pipe network. Therefore, pressure-dependent demand (PDD) analysis is an important tool used for analyzing the networks which are pressure deficient. This paper describes a small hypothetical model that simulates the disaster scenario due to failure of a water storage dam in an event of disaster such as flood. A PDD analysis of such situation has been carried out using WaterGEMS software. The paper also aims to prepare action plans of partial recovery of water supply in such crisis conditions.