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 levels. A further study in the Columbia River estuary found that high concentrations of organic nutrients and low amounts of inorganic nitrogen were associated with the red waters. "M. rubra" blooms also created areas characterized by high primary production and increased levels of particulate organic matter during this period, thus shifting the trophic status in red water areas from net heterotrophy towards autotrophy, making "M. rubra"'s red blooms a seasonal biogeochemical hotspot of the Columbia River estuary. Nutrient cycling is affected by human alteration refereed to as anthropogenic impacts. The Columbia River Basin is home to nearly five million residents,