Odisha is one of the States of India.It is located between the parallels of 17.49'N and 22.34'N latitudes and meridians of 81.27'E and 87.29'E longitudes. It is bounded by the Bay of Bengal on the east; Madhya Pradesh on the west and Andhra Pradesh on the south. It has a coast line of about 450 kms. It extends over an area of 155,707 square kms. Accounting about 4.87 of the total area of India. According to the 1991 census, it has a total population of 31,512,070 (3.73 percent of the total population of India) out of which about 16,237,000 are male and 15,275,070 are female.
On the basis of homogeneity, continuity and physiographical characterstics, Odisha has been divided into five major morphological regions : the Odisha Coastal Plain in the east, the Middle Mountainous and Highlands Region, the Central plateaus, the western rolling uplands and the major flood plains.
The Odisha Coastal Plains
The Odisha Coastal Plains are the depositional landforms of recent origin and geologically belong to the Post-Tertiary Period. The 75 metre contourline delimits their western boundary and differentiates them from the Middle Mountainous Region. This region stretches from the West Bengal border, i.e. from the River Subarnarekha in the north to the River Rushikulya in the south.
This region is the combination of several deltas of varied sizes and shapes formed by the major rivers of Odisha, such as the Subarnarekha, the Budhabalanga, the Baitarani, the Brahmani, the Mahanadi, and the Rushikulya. Therefore, the coastal plain of Odisha is called the "Hexadeltaic region" or the "Gift of Six Rivers". It stretches along the coast of the Bay of Bengal having the maximum width in the Middle Coastal Plain (the Mahanadi Delta), narrow in the Northern Coastal Plain (Balasore Plain) and narrowest in the Southern Coastal Plain ( Ganjam Plain). The North Coastal Plain comprises the deltas of the Subarnarekha and the Budhabalanga rivers and bears evidences of marine transgressions. The Middle Coastal Plain comprises the compound deltas of the Baitarani, Brahmani and Mahanadi rivers and bears evidences of past 'back bays' and present lakes. The South Coastal Plain comprises the laccustrine plain of Chilika lake and the smaller delta of the Rushikulya River.
The Middle Mountainous and Highlands Region
The region covers about three-fourth of the entire State. Geologically it is a part of the Indian Peninsula which as a part of the ancient landmass of the Gondwanaland. The major rivers of Odisha with their tributaries have cut deep and narrow valleys. This region mostly comprises the hills and mountains of the Eastern Ghats which rise abruptly and steeply in the east and slope gently to a dissected plateau in the west running from north-east (Mayurbhanj) to north-west (Malkangirig). This region is well marked by a number of interfluves or watersheds. The Eastern Ghats is interrupted by a number of broad and narrow river valleys and flood plains. The average beight of this region is about 900 metres above the mean seal level.
The Central Plateaus
The plateaus are mostly eroded plateaus forming the western slopes of the Eastern Ghats with elevation varying from 305-610 metres. There are two broad plateaus in Odisha : (i) the Panposh - Keonjhar -Pallahara plateau comprises the Upper Baitarani catchment basin, and (ii) the Nabrangpur - Jeypore plateau comprises the Sabari basin.
The Western Rolling Uplands
These are lower in elevation than the plateaus having heights varying from 153 metres to 305 metres.
There are four groups of rivers which flow through Odisha into the Bay of Bengal (Table-2). They are :
(i) Rivers that have a source outside the State (the Subarnarekha, the Brahmani and the Mahanadi).
(ii) Rivers having a source inside the State(the Budhabalanga, the Baitarini, the Salandi, and the Rushikulya).
(iii) Rivers having a source inside the Odisha, but flow through other states (the Bahudu, the Vansadhara, and the Nagavali).
(iv) Rivers having a source inside Odisha, but tributary to rivers which flow through other states (the Machkund, the Sileru, the Kolab, and the Indravati).
It is the major river of Odisha and the sixth largest river in India. It originates from the Amarkantak hills of the Bastar Plateau in Raipur district of Madhya Pradesh. It is about 857 kms. Long (494 kms. In Odisha) and its catchment area spreads over 141,600 sq.kms. (65,580sq.kms.) in Odisha). The river carries on an average about 92,600 million m of water.
It is the second largest river in Odisha. It originates as two major rivers like the Sankh and the Koel from the Chhotanagpur Plateau of Bihar and both join at veda Vyasa near Rourkela of Sundargarh district of Odisha forming the major River Brahmani. It flows through the Easter Ghats in Sundargarh, Kendujhar, Dhenkanal, Cuttack and Jajpur districts into the Coastal Plains and enters into the Bay of Bengal along with a combined mouth with the Mahanadi known as the Dhamra. The Brahmani is 799 kms. Long (541 kms. In Odisha) and its catchment area spreads over 39,033 sq.kms. in Odisha).
It originates from the Gonasika hills of the keonjhar districts. It is 365 kms long and its catchment area spread over 12,790 sq. kms . It entres into the Bay of Bengal after joining of the Brahmani at Dharma mouth near Chandabali Subarnrekha.
It orginates from the Chhotnagpur plateau of Bihar. It is 433kms (70kms in Odisha ) and has a catchment area of 19,500 kms (3,200kms in Odisha ) with a mean annual flow of 7,900 million n.
It orginates from the easterns slops of the Similipala massif. It is about 175 kms long having a total catchment area of 4840 sq. kms with an annual flow of 2177 million m . It is major tributaries are the Sone, the Gangadhar, the Catra etc.
It originates from the Rushyamala hills of the eastern ghats in Phulbani district. It is 165 kms long with 8900 sq. kms of catchment areas. It's tributaries are the Baghua the Dhanei Badanadi etc. It has no delta at its mouth.
It originates from the Ramgiri hills of the eastern ghats in Gajapati districts and joins the bay of Bengal in Andhra Pradesh . Its length 73 kms having a catchment area of 1250 sq. kms .
It originates from the Flanks of the Durgakangar hills (Lingaraj hills) of the eastern ghats in Kalahandi districts. It is 230 kms long out of which only 150 kms in Odisha. It entres in to the Bay of Bengal at Kalingapatnam in Andhra Pradesh. It has a catchment area of 11500 sq. kms .
It originates from the Bijipur Hills of the eastern ghats near Lanji garah . It is 210 kms long out of which 100 kms is in Odisha. It has a total catchment area of about 9410 sq. kms.
It originates from the Meghasani Hills of the Similipal massif in Keonjhar district. It is 144 kms long with a catchment areas of 1793 sq. kms .
It originates from the eastern ghats in Kalahandi districts. It is 530 kms long with a catchment area of 41700 sq. kms as a tributary it flows into the Godabari river.
It originates from the Sinkaran hills of the eastern Ghats in koraput districts. It has catchment areas of 20400 sq. kms .
There are a number of Mountain springs and hotspring in Odisha. The Badaghagara and Sanaghagara in Keonjhar districts Satpasajya in Denkanal districts the Chandikhole in Cuttack distrcts the Barunei in Khorda distrcts, the Narayani and Nirmalajhar in Ganjam and Puri districts, the Patalaganga in Kalahandi districts, the Nursinghanath in Sambalpur distrcts and the Harisankar in Bolangir distrcts and some of the important mountain springs in Odisha .
Most of the rivers, either at the point of origin or over the mountainous bed, have waterfalls. The Barehipani and Joranda (Similipal ) in Mayurbhanja districts, Sanaghagara and Badaghagara in Keonjhar district Padhanpuri in Deogarh district khandadhar (Banei) in Sundargarh district Phurlijharan, Khandabaladhar, and Rabandhara in Kalahandi district Kentamari and Putudi in Boudh and Phulbani district DumDuma in Malkangiri district and Bogra in Koraput district are some of the major waterfalls of Odisha.
The Chillika Lake is blakish water lagoon located in the southern part of the Odisha coastal plane. It areas varies 780 sq. kms and 144 sq. kms from winter two monsson months having 71 kms long 32 kms breadth. It salinity decleans to a minimum during the monsson. But in winter due to the overflow of the tidal water through the narrow opening from the Bay of Bengal, it is maximum.
Ansupa is a sweet water lake located in Banki of Cuttack districts. It is 3 kms in lengh and 1.5 kms in breadth. Sara is another sweet water lake located near Puri. It is 5 kms in length and 3 kms in breadth. Kanjia is another sweet water lake with about 134 acres of area located in Nandankanan of Cuttack districts near Bhubaneswar.