OPTIMAL RESTORATION STRATEGY OF A WATER PIPELINE NETWORK IN SURIGAO CITY, PHILIPPINES

Abstract

Quick recovery of water services immediately after an earthquake is critical. This is tominimize hazards to environmental sanitation and consequent health problems caused by the lack of potablewater supply. It is necessary therefore that water lifeline operators establish restoration strategies to deal withdamage scenarios in their respective concession areas specifically during extreme seismic events. The recent6.7 magnitude earthquake in Surigao City due to the movement of the Philippine Fault Zone: Surigaosegment underscored this need. However due to the complexity of the network a systematic restorationsequence that minimizes restoration time and maximizes delivery of water service should be employed. Inthis research, the authors employed Horn’s algorithm to determine the optimal restoration strategy of apipeline network in Surigao City, Philippines. The repair sequence starts with the determination of a minimalspanning tree of the given pipeline network. The water source is designated as the root of this tree while thenodes represent the water demand at specific areas. The edges of the tree structure representing the pipelinesconnect the nodes. The assigned numeric value or weight of an edge (link) denotes the time to repair thatspecific pipeline. This value is a function of the length of the pipeline. The results show that an optimal jobsequence may be carried out by considering maximal ratios of expanding family trees within the network. Aleast penalty function is a consequence of the optimal repair job sequence.