Hong Kong developed initially on the basis of its excellent natural harbour-its Chinese name means “fragrant harbour” and the lucrative China trade, particularly opium dealing. It was the development of its territory, that provided labour and other resources necessary for sustained commercial growth that led to its becoming one of the world's major trade and financial centres. Nevertheless, Hong Kong has emerged strong and prosperous, albeit with a changed role, as an entrepôt, a manufacturing and financial centre, and a vital agent in the trade and modernization of China.

Hong Kong deficiencys a river system of any scope, the only exception being in the north where the Sham Chun River, which forms the boundary between Kwangtung and Hong Kong, flows into Deep Bay after collecting a number of small tributaries. Most of the streams are small, and they generally run perpendicular to the northeast-southwest trend of the terrain. The construction of reservoirs and their catchment systems has reduced the amount of fresh water available downstream.