B A II YEAR (PPU) topic: Physiography of Bihar paper-3, unit-5 By. Dr Bhawana Nigam Dept. of Geography, A N College, Patna. Introduction The state of Bihar lies in between Himalayas mountain in North and Chotanagpur plateau in the south. The rivers from north and south have played significant role in the formation of Bihar’s Physiography. The physiography consist of – hilly areas, plain areas and outliers of Chotanagpur plateau. It can be further divided into:- 1) THE SOMESHWAR HILLY RANGE 2)THE NORTH BIHAR PLAIN 3) THE SOUTH BIHAR PLAIN 4) THE SOUTHERN HILLY TERRAIN. The Someshwar hilly range & Terai region This hilly area found in the NW part of the state ( west Champaran) It consist of a range of hilly areas of SHIWALIK which is known as Someshwar range and the Ramnagar Dun. This region consist of a range of low hills about 30 km long Below these hills ; extend southward and eastward an elongated moist TERAI region. Further south there is a sub-terai belt Marshy land. This region further subdivided into: 1) Someshwar range 2) Ramnagar dun. CONT…. 1) SOMESHWAR RANGE:- This Regin consist of different range of hills and valleys, all parallels to the Nepal border in the NW to SE direction. The avg. width of this range is 4-6 km. The avg. height of his range is about 450 mts. The highest peak is Someshwar fort (865 mts.). There are some natural passes formed by the river. This range consist of relatively young sedimentary rocks of which sandstone and pebbles are important. Cont… Ramnagar Dun:- It is the southern range of NW hilly region. Extending for about 30 kms average width of 6-8 kms. Terai region:- South of hilly areas exist the sub- mountain tract. This is the land which is mostly covered by forest and marshy land and braided river channels. The Bihar plain:- The state is naturally divided by the Ganges (Ganga) River into two regions—the North Bihar Plains and the South Bihar Plains, which together form part of the middle Gangetic Plain. North Bihar Plain:- Except for the foothills of the Himalayas in the extreme northwest, the North Bihar Plain is a flat alluvial region, less than 250 feet (75 metres) above sea level and prone to flooding. The Ghaghara, the Gandak, the Baghmati, the Kosi, the Mahananda, and other rivers flow down from the Himalayas of Nepal and make their way to the Ganges in frequently changing channels. Depressions and lakes mark the abandoned courses of streams. The Kosi River, long known as the “Sorrow of Bihar” for its tendency to cause destructive floods, has been confined within artificial embankments. The soil of the northern plain consists mostly of new alluvium—chalky and light-textured (mostly sandy loam) west of the Burhi (Old) Gandak River and nonchalky and heavy-textured (clay and clay loam) to the east. South Bihar plain The land of the South Bihar Plain is more varied than that of its northern counterpart, with many hills rising from the level alluvium. The southern rivers, with the exception of the Son, are all small; their water is diverted into irrigation channels. The soil consists mainly of older alluvium, composed of a darkish clay or yellowish loam, with poor, sandy soils predominating toward the south of this region. In the southwest, beyond the Son River valley, lies the Kaimur Plateau, with horizontal sandstone strata over a limestone base. The southern hilly terrain. This hilly terrain lies in the extreme south of the South Bihar plain. Geologically, this region is made up of hard rocks of Genesis, Schist and Granite. It include areas of Kaimur, hilly district of Gaya, Rajgir, and Jyethian in Nalanda, Nawada and Banka. THANKS..