Ganges Basin (112,490 km²), West Bengal (71,485 km²), Haryana (34,341 km²), Himachal Pradesh (4,317 km²) , Delhi, Arunachal pradesh(1,484 km²), the whole of Bangladesh, Nepal and Bhutan. Several tributaries rise inside Tibet before flowing south through Nepal. The basin has a population of more than 500 million, making it the most populated river basin in the world. 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
Nutrient cycling in the Columbia River Basin eutrophication in part due to the use of the river and its tributaries to irrigate over seven million acres of farmland, an extraction that comprises an average of 93 percent of daily water use in the basin. Natural run-off caused by precipitation and snowpack melt across agricultural lands further transports more of these nutrients into the river. In the late 1990s, the nitrogen load in the Columbia river was over twice the concentration historically observed. Forests are important terrestrial sinks for nutrients due to the ability of vegetation to sequester excess nutrients into their biomass. Additionally, plant roots stabilize soils