Assam - Ministry of Environment and Forests

3.0 STUDY AREAAssam is one of the 7 states of Northeast India. It extends between the latitudes of 24°8’ N - 28°2’ N andlongitudes of 89°42’ E - 96° E. The T-shaped state is sprawled in an area of 78,438 km²(Figure-3). It isbordered by the Indian states of Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, andWest Bengal. The name "Assam" is derived from the term "Asom" which, in Sanskrit, refers to unequal orunrivalled. The uneven topography of the land, full of hills and plains might, have contributed to the name.The Mongolian Ahom dynasty that had ruled Assam for more than six hundred years might also be the causefor the name. Assam can be broadly divided into three distinct physical units, the Brahmaputra Valley in thenorth, the Barak Valley in the narrow protruding south, and the state’s hilly region (Mikir and Cachar )separating the two valleys. Entering Assam, the Brahmaputra becomes a braided river and along with itstributaries, creates the flood plain of the Brahmaputra Valley. The Brahmaputra Valley in Assam isapproximately 80 to 100 km wide and almost 1000 km long and the width of the river itself is 16 km at manyplaces within the valley. The hills of Karbi Anglong and North Cachar and those in and around Guwahati andNorth Guwahati (along with the Khasi and Garo Hills) are originally parts of the South Indian Plateau system.These are eroded and dissected by the numerous rivers in the region. Average height of these hills in Assamvaries from 300 to 400mt. The southern Barak Valley is separated by the Karbi Anglong and North CacharHills from the Brahmaputra Valley in Assam. The Barak originates from the Barail Range in the border areasof Assam, Nagaland and Manipur and flowing through the district of Cachar, it confluences with theBrahmaputra in Bangladesh. Barak Valley in Assam is a small valley with an average width and length ofapproximately 40 to 50 km.Assam weather is characterized by heavy downpour and humidity. The hilly areas usually experience subalpineclimatic condition, while excessive sultriness is observed in the plain lands of Assam. The humidity thatis brought into Assam by the southwest monsoons, shower an average annual rainfall of 120 inches or moreon the great Brahmaputra valley and the surrounding region. The temperature ranges from a maximum of 29°to a minimum of 16°. Assam's economy is based on agriculture and oil. Assam produces a significant part ofthe total tea production of the world. Assam produces more than half of India's petroleum.The current state capital of Assam, Guwahati, was known in ancient time as Pragjyotishpura or The EasternCity of Light. Other major towns are Dhubri, Barpeta, Dibrugarh, Tinsukia, Jorhat, Nagaon, Sivasagar, Silchar,Tezpur. The population of Assam is 26.66 million according to 2001 census and is scattered over 26312villages. Administratively, it is divided into 23 districts: Barpeta, Bongaigaon, Cachar, Darrang, Dhemaji,Dhubri, Dibrugarh, Goalpara, Golaghat, Hailakandi, Jorhat, Kamrup, Karbi Anglong, Karimganj, Kokrajhar,Lakhimpur, Marigaon, Nagaon, Nalbari, North Cachar Hills, Sibsagar, Sonitpur, and Tinsukia.The spatial framework was prepared using 15’ x 15’ grid. The state is covered by 171 Survey of Indiatopographic maps on 1:50,000 scale that form the spatial frame work for mapping (Figure 4).A detail of district information followed in the atlas is given in Annexure-II.7