Test: Water Resources

Irrigation is needed because of spatio-temporal variability in rainfall in the country.

Because they are coarse grained.

The total replenishable groundwater resources in the country are about 432 cubic km. The Ganga and the Brahmaputra basins have about 46 percent of the total replenishable groundwater resources.

Over withdrawals in some states like Rajasthan, and Maharashtra has increased fluoride concentration in ground-water, and this practice has led to increase in concentration of arsenic in parts of West Bengal and Bihar.

The areas with more than 40 percent of net irrigated area are called areas of high proportion of irrigated area. Punjab with 91% is at top followed by Haryana with 85%.

It is the largest basin in India with area about 861452 sq. km. It originates from the Gangotri glacier in Himalaya and traverses about 2,525 km across the states of Uttarakhand, Uttar Pradesh, Bihar, Jharkhand and West Bengal before falling into the Bay of Bengal. Its principal tributaries are Yamuna, Chambal, Banas, Kali Sindh, Parbati, Sind, Betwa, Dhasan, Keri, Gomti, Sarda, Ghaghara, Gandak, Son, Damodar, and Hooghly, Ramganga, and Mahananda.

Tamilnadu has highest ground water utilisation among south Indian states. Tamil Nadu has historically been an agricultural state and is a leading producer of agricultural products in India. In 2008, Tamil Nadu was India's fifth biggest producer of rice, the largest producer of bananas, flowers, tapioca, the second largest producer of mango, natural rubber, coconut, groundnut and the third largest producer of coffee, sapota, tea and sugarcane.

The north India has highest surface water in the form of rivers etc. because the rivers of north India are perenial in nature. They are snow-fed rivers of Himalayas. Rainfall is also high in the catchment area of these rivers.

Uttar Pradesh has a large number of perennial rivers as well as ample ground water supply .

Gujarat has the largest proportion of its net irrigated area under well irrigation. Uttar Pradesh has the largest area under irrigation in terms of total acreage.

It is a very cold area. The water is mostly in the form of snowin higher altitudes. This region is characterized by mild summer and severe winter with mean annual temperature of less than 8⁰C and mean annual rainfall of less than 150 mm.