5-On Variability of Hydrological Wet Season Seasonal Rainfall and Rainwater Potential of the River Basins of India (1831-2006)

Abstract

In tropical monsoonal climate rainfall is subject to strong seasonality. Further, attributes of rainy season (starting date, ending date and duration) exhibit large spatial and temporal variations. Numerous notions of rainy season exist in the real world and the literature,- e.g. green season, growing season, wet season, monsoonal rainy season and wet period. For Indian region, a hydrological wet season (HWS) is defined as continuous period with each of the monthly rainfall greater than 50mm'. Climatological and fluctuation features of important parameters of the HWS (starting and ending dates and duration, seasonal rainfall/rainwater and surplus rainfall/rainwater potential) are described Jar the 11 major and 36 minor river basins as well as the West Coast Drainage System (WCDS) and the whole country using highly quality-controlled monthly rainfall from well-spread network of 316 raingauge stations from earliest available year (sometimes going hack to 1813) up to 2006.