Orissa

Orissa extends from 17^o 49'N to 22^o 34'N latitude and from 81^o 29'E to 87^o 29'E longitude on the eastern coast of India. It has an area about 155,707 Sq Km. according to the Census of India 1991. It is bounded by West Bengal in north-east, Bihar in the north, Madhya Pradesh in the west, Andhra Pradesh in the south and the Bay of Bengal in the east. Orissa was separated from Bihar and came into existence on 1 April 1936. The capital was established at the historic city of Cuttack, located at the apex of the Mahanadi delta. In 1956, it shifted to Bhubaneswar, a planned modern town of the post-independence period.

Physiographically, Orissa can be divided into three broad regions 1) The Coastal plains, (2) The Middle mountainous country (3) The Plateaus and rolling up lands. 

Coastal Plains:

The coastal plains of Orissa stretch on the eastern coast of India from the Subarnarekha in the north-east to the Rushikulya in the south-west. This fertile region is known as the 'rice bowl' of Orissa. This is narrow in the north, widest in the middle, narrowest in the Chilika coast and broad in the south.

The coastal plain is a gift of six major rivers. The formation of the coastal plains depends on the rivers and their catchment's area. The rivers are: From north to the south, the Subarnarekha, the Burhabalanga, the Baitarani, the Brahmani, the Mahanadi and the Rushikulya. Most of the rivers have failed to develop true deltaic characteristics because of the strong off shore current which moves from Chennai to the Andhra coast and passes through Orissa coast.  

According to the location, the coastal plain can be divided into three sub regions 

a)  The north coastal plains - the deltas of the Subarnarekha and the Burhabalanga upto the river Baitarani

b) The middle coastal plains - the combined deltas of the Baitarani, the Brahmani and Mahanadi

c) The southern coastal plains - the Rukshikulya plains, it can be divided into three zones parallel to the shoreline

 i) The salt track along the coast.

 ii) The arable tract or rice country in the middle

 iii) The sub-montane tract to the west

The Salt tract:

The salt tract is a narrow belt which stretches just beyond the shore line for about 4.8 to 9.6 Km in land. In many places it is impregnated with salt and is completely deprived of agriculture. The innumerable sluggish and blackish streams make the area difficult to traverse. In the Mahanadi delta, this salt tract is covered with tidal forest known as the  "Little Sunderbans", off Paradeep-Dhamra coast. In the Devi-Daya sector, Casuarina forests and plantations are found. The forest belt all along the coast merges with a narrow belt of pasture.

The Arable tract:

The grass belt merges into the vast plains. The endless stretches of rice lands is the fundamental characteristic. Most of these places are occupied by village sites so as to be free from the annual inundation. The rivers have formed levees and during high floods they inundate vast areas, causing grave danger to human lives, cattle population and agriculture parts of this arable tract are protected from floods and are irrigated by gravity. 

This is the richest part of the whole of Orissa as far as agriculture is concerned.

The Sub montane tract:

This is the meeting zone of the arable tract and the spurs of the Eastern Ghats. It is termed as the 'zone of transition'. Soil erosion is rampant here. Under this predominating red soil, blocks of laterite are buried and at times they crop up to the surface, turning the area barren and desolate. In this zone low level laterites are formed. But patches of fertile area are not uncommon having rich vegetation. The natural vegetation varies from prickly thorns and stunted shrubs to Sal forests. The absence of a coastal forest belt is most striking. This is because of the lack of a marshy  strip due to higher orography.

The Mahanadi Delta:

The Mahanadi delta has developed in seven different stages. The stages of development have occurred at 26, 18, 15, 9, 6 and 1.5 metre contours. After the seventh stage of delta development there is an upliftment  as a result of which three sets of parallel sand dumes developed along the coast. These raised sand ridges brought changes in the drainage pattern and in deltaic morphology. These parallel sand dumes have the maximum development between the Chilika and the Devi mouth and from there up to north of Dhamra. Several lagoons of varied sizes have been formed. The best examples are the Sar Pata and the Samagara Pata located to the north of Puri.

The Coastal Line:

Orissa has a coastal line of 529 Km from the marshes of Ichhapuram in the south to the east of Subarnarekha in the north-east. The Orissa coast has bulged out in the middle portion from Brahmagiri on Chilika lake in the south-west to Chandbali in the north-east where the Mahanadi, the Brahmani and the Baitarani have formed a combined delta.

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