The basin comprises semi-arid valleys in the rain shadow north of the Himalaya, densely forested mountains south of the highest ranges, the scrubby Shiwalik foothills and the fertile Gangetic Plains. Central highlands south of the Gangetic Plain have plateaus, hills and mountains intersected by valleys and river plains. The important soil types found in the basin are sand, loam, clay and their combinations such as sandy loam, silty clay etc.
The annual surface water potential of the basin has been assessed as 525 km³ in India, out of which 250 km³ is utilisable water. There is about 580,000 km² of arable land; 29.5% of the cultivable area of India.
Water-related issues of the basin are due to both high and low flows. In India, the states of Uttar Pradesh, Bihar and West Bengal are affected by floods. Bangladesh – at the confluence of Brahmaputra River and Ganges River – suffers from severe floods almost every year. Northern Ganges tributaries such as Kosi, Gandak and Mahananda are the most flood-prone, but southern tributaries also contribute. Low flows are caused by scarcity of rainfall outside the summer Monsoon, and sometimes by failure of this monsoon to develop to its normal extent.