Northeastern hill ranges
stretch over six Indian states Assam, Nagaland, Manipur,
Mizoram, Tripura and Meghalaya, extending over Bangladesh and
northern Myanmar, touching the southern slopes of the Brahmaputra
valley and the northern, eastern and southern slopes of the
Barak valley. The Meghalaya plateau covers the entire state
of Meghalaya and the Karbi hills of Assam.
The climate and rainfall of the area varies considerably
across the region. Encircled by hills and plateaus, rainfall
varies even more than temperatures. The average annual rainfall
reaches a peak of 13,390 mm in the Cherrapunji-Mawsynram region.
But areas that fall in the rainshadow region of the Meghalaya
plateau need irrigation. While the northern slopes of the
Brahmaputra valley receive an annual average rainfall of 2,500
mm, the area south of the valley and the northern part of
Meghalaya receive an annual rainfall of about 2,000 mm.
Distribution of the population in the Northeast is also very
uneven. Within the plains there are pockets of very high population
density, such as the Manipur plains (400 persons/sq km) and
the Nowgong plains (302 persons/sq km). The vast hill tracts,
however, have a low population density.
The water resources potential of the region is the largest
in the entire country. Given its heavy rainfall, it also has
abundant groundwater resources. But only a small part of the
region has been studied to estimate the groundwater potential.
The maximum scope for development of groundwater exists in
Assam, Tripura and Arunachal Pradesh. The available surface
water resources have hardly been tapped because of the rugged
nature of the terrain. Hence, cultivation in the region is
largely rainfed and jhum cultivation (shifting cultivation)
has been widely adopted.2
Nonetheless, there are documented instances of some indigenous
rainwater harvesting systems used for cultivation, of which
some are ingenious. Settled agriculture is practised in the
form of irrigated terrace cultivation in parts of Nagaland
and a few villages of Meghalaya. Channels are dug to irrigate
these fields. The other chief indigenous source of irrigation
is the bamboo irrigation system found in parts of Meghalaya,
and in some villages in the Mokokchung district of Nagaland.
Find more about
Techniques prevalent in this region
who harvest rain