Following is from http://teamorissa.org/water.asp.

 

An overview

  Orissa is one of the few states in the country, which is endowed with abundant water resources. But this resource is very unevenly distributed over time and space. The rainfall which is the main source of water varies from about 1200 mm in southern coastal plain to about 1700 mm in northern plateau. The long-term average annual rainfall in the State is of the order of 1482 mm, which is equivalent to 230.76 billion cubic metres (BCM) of water. Though substantial in quantity, 78% of the above is received in the monsoon season (June to September) and remaining 22% is available in eight months. Of the total precipitation, a part is lost by evaporation, transpiration and deep percolation and a part stored in the form of ground water reserve and the remaining appears as surface runoff. The groundwater reserve and surface runoff constitute the water resources of the state. The water resources scenario of Orissa and India are given in the table below.
 

Water Resources: India & Orissa (Unit in BCM)

 
Description
India 
Orissa

Annual Precipitation

4000
230.76

Average Annual Water Resources 
1869
141.408*

Utilizable Water Resources (Surface & Ground) 
1122
108.147

Utilizable Resources (% of precipitation)

28%
47%
 

* include trans-boundary flow

 
Surface Water Resources:

 The State is blessed with an extensive network of rivers & streams. As per assessment made in 2001, the average annual availability of surface water resources is about 120.397 BCM. Out of the above, the yield from its own drainage boundary is 82.841 BCM and inflow from neighboring states through interstate rivers is 37.556 BCM. Considering the topography and geological limitations, 75% of the average annual flow can be utilized. Due to increasing demands for water for various uses, an attempt has been made to assess the availability of Water Resources by the year 2051. The assessment reveals that the surface water availability from its own drainage boundary remains more or less fixed but the inflow of surface water from neighboring states will be reduced from 37.556 BCM to 25.272 BCM. The following table shows the assessed inflow of surface water pertaining to the years 2001 and 2051. 

Assessed Inflow of Surface Water Scenario: 2001

 
Basin Name

Average Annual flow 

(BCM)

75% dependable flow 

(BCM)
Own

Outside State

Total
Own

Outside State

Total
Mahanadi
29.90
29.255
59.155
25.508
23.225
48.732
Brahmani
11.391
7.186
18.577
8.849
5.521
14.011
Baitarani
7.568
–
7.568
5.434
–
5.434
Rushikulya
3.949
–
3.949
2.782
–
2.782
Vamsadhara
5.083
–
5.083
3.881
–
3.881
Budhabalanga
3.111
–
3.111
2.521
–
2.521
Kolab
11.089
–
11.089
8.885
–
8.885
Indravati
6.265
–
6.265
4.451
–
4.451
Bahuda
0.438
–
0.438
0.213
–
0.213
Nagavali
2.853
–
2.853
2.322
–
2.322
Subernarekha
1.193
1.115
2.308
1.193
1.115
2.308
Total 
82.841
37.556
120.397
65.679
29.861
95.540
                   
 
 
Assessed Inflow of Surface Water (Future Scenario: 2051)
 
Basin Name

Average Annual flow 

(BCM)

75% dependable flow 

(BCM)
Own

Outside State

Total
Own

Outside State

Total
Mahanadi
29.90
21.039
50.939
25.508
16.702
42.210
Brahmani
11.391
3.118
14.509
8.849
2.395
10.884
Baitarani
7.568
–
7.568
5.434
–
5.434
Rushikulya
3.949
–
3.949
2.782
–
2.782
Vamsadhara
5.083
–
5.083
3.881
–
3.881
Budhabalanga
3.111
–
3.111
2.521
–
2.521
Kolab
11.089
–
11.089
8.885
–
8.885
Indravati
6.265
–
6.265
4.451
–
4.451
Bahuda
0.438
–
0.438
0.213
–
0.213
Nagavali
2.853
–
2.853
2.322
–
2.322
Subernarekha
1.193
1.115
2.308
1.193
1.115
2.308
Total 
82.841
25.272
108.113
65.679
20.212
85.891
                   
 Source-State Water Plan 

Ground Water Resources: 

The natural recharge of ground water takes place through percolation from land after rain events. The quantum of dynamic ground water, which can be annually extracted, is generally reckoned as ground water potential. As per assessment made in 2001, the total annual replenishable ground water resource of the state is 21.011 BCM, out of which 60% i,e 12.607 BCM is safe and usable.

 

       Per-capita Water Availability: 

The

The per-capita water availability is reducing progressively owing to increase in population. In 2001, the average per-capita water availability (both surface and ground) in the state was around 3359 cubic meter (cum) per year, as compared to the national average of 1820 cum. With the projected future population the per-capita water availability in the state will reduce to 2218 cum in 2051. Per-capita water availability less than 1700 cum is termed water stress condition while if it falls below 1000 cum, it is termed as water scarce condition. Though per-capita availability of water resources in our state is relatively favorable in the aggregate, the Rushikulya basin will experience a scarcity condition and basins like Budhabalanga and Bahuda will be close to scarcity condition by 2051.

 

  Water Requirement:

Water has always played an important role in providing livelihood, hygiene and environmental securities since the dawn of civilization. The demand pattern is changing rapidly with increase in population, urbanization and rapid industrialization. Keeping in view the constraints of water availability and the variety of its uses, water allocation issues need to be addressed in a wise manner. Considering this, the present and future requirement of water for all purposes have been assessed, which is given in the table below. 

 

Water requirements for different uses ( Qty. in BCM)

 
Uses
Year-2001
Year-2051
Surface
Ground
Total
Surface
Ground
Total
Domestic
0.798
1.198
1.996
1.202
1.803
3.006
Agriculture
18.00
4.688
22.688
40.00
9.408
49.408
Industry
0.606
0.100
0.706
1.750
0.20
1.950
Environment
21.00
8.40
29.40
21.00
8.40
29.40
Others
0.10
0.10
0.200
0.20
0.20
0.40
Total
40.504
14.486
54.99
64.152
20.01
84.463
                   
 

Water     Storage: 

A storage capacity of 17.00 BCM has so far been developed through completed major, medium and minor(flow) projects. Besides, the projects under construction will contribute to an additional 1.47 BCM. The details are given in the following table.

Reservoir Storage Status as on 31.03.2007 ( Qty. in BCM)

 
Category
Completed Projects

Ongoing Projects 
No
Capacity
No
Capacity
Major
7
14.86
4
1.04
Medium
38
1.30
9
0.43
Minor
2340
0.85
–
–
Total
2385
17.01
13
1.47