Water resources development plays an important role in achieving multifaceted economic and social development of a nation. India is endowed with substantial water resources in accordance with latest estimates of Central Water Commission, annual runoff of its river systems aggregates to 1800 km3 constituting 4 % of total annual water flows of the world. As the population of India is about 16% of world's population, there is greater pressure on use of water to meet the demand in this country. Rainfall-generated runoff is very important in various activities of water resources development and management such as flood control and its management, irrigation scheduling, design of irrigation and drainage works, design of hydraulic structures, and hydro-power generation etc. Determining a robust relationship between rainfall and runoff for a watershed has been one of the most important problems for hydrologists, engineers, and agriculturists.
