摘要:A large part of the Medan City, a city of more than 2 million people, experiences frequent floods which cost a lot of damage due to the inundation. The objective of this study is to estimate the area of inundation and the consequent damage cost with reference to the predicted discharges of the rivers crossing the city in a certain return period. Two main watersheds are involved here, i.e. the watersheds of Belawan and Deli.The relevant data for the flood estimation include rain fall, watersheds, as well as river profiles and cross-sections. The computed and mapped flood affected area is then stacked on top of the city maps in a GIS framework. By identifying the number of affected houses, the damage cost for a return period of flood can be estimated in a relative accurate manner. Also the affected city infrastructures can be shown and listed.