When and where did the science of hydrology begin? lt is difficult to answer, as the roots of modern hydrology lie deeply buried in antiquity. From the beginning, man realized that water is essential for survival, and hence it is not surprising that evidences of the earliest civilizations have been found along the banks of rivers: the Tigris and Euphrates in Mesopotamia, the Nile in Egypt, the Indus in India, and the Huang-Ho (Yellow River) in China. Gradually, they developed their water supply systems, constructed dams and levees, made channel improvements, and dug canals for drainage and irrigation. The presence of these structures proves that man had some knowledge of water, its powers and limitations – although it was admittedly not very scientific. The first hydrologic principles were extremely crude, but in the beginning, man was primarily interested in controlling nature; and only later, during the Hellenic Civilization (around 600 B.C.), did he try to understand nature. It may be said that one cannot treat a branch of science as such until a certain degree of development has taken place, but who will define and measure that degree? To paraphrase the great historian of science, George Sarton, a 2-in. high Sequoia gigantes may not be very conspicuous, but it is still a Sequoia. After all, when the first primitiva mathematician realized that there was something similar about three palm trees and three donkeys, how abstract was his thought?
By Asit K. Biswas, Chapter 1 of the book: History of Hydrology, 1970, North-Holland Publishing Company, Amsterdam.