About Narmada Basin

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Brief Description of the Basin

The Narmada River, rises in the Amarkantak Plateau of Maikala range in the Shahdol district of Madhya Pradesh at an elevation of 1057 meters above mean sea level at a latitude 22° 40' north and a longitude of 81° 45' east. The river travels a distance of 1,312 km before it falls into Gulf of Cambay in the Arabian Sea near Bharuch in Gujarat. The first 1,079 km of its run are in Madhya Pradesh. In the next length of 35 km, the river forms the boundary between the States of Madhya Pradesh and Maharashtra. Again, in the next length of 39 km, it forms the boundary between Maharashtra and Gujarat. The last length of 159 km lies in Gujarat.

The Narmada basin extends over an area of 98,796 sq. km and lies between longitudes 72° 32' E to 81° 45' E and latitudes 21° 20' N to 23° 45' N. The statewise distribution of the drainage area is given in Table 11.1. The catchment area up to Sardar Sarovar dam is 88,000 sq. km. The basin is bounded on the north by the Vindhyas, on the east by the Maikala range on the south by the Satpuras and on the west by the Arabian Sea. Most of the basin is at an elevation of less than 500 meters above mean sea level. A small area around Panchmarhi is at a height of more than 1,000 meters above mean sea level.

Drainage Area

Statewise drainage area of Narmada basin

State

Drainage Area (sq. km)

Madhya Pradesh

85,859

Maharashtra

1,538

Gujarat

11,399

Total

98,796

Major Tributaries and sub-tributaries

Narmada River has 41 tributaries. Of these, 22 are on the left bank and 19 on the right. The important tributaries/sub-basins of the Narmada are Barna River, Ganjal River, Chhota Tawa River, Hiran River and Jamtara River, Kolar River, Orsang River, Sher River and Tawa River

Climate

The climate of the basin is humid tropical ranging from sub-humid in the east to semi-arid in the west with pockets of humid or per humid climates around higher hill reaches.

The Tropic of Cancer crosses the Narmada basin in the upper plains area and a major part of the basin lies just below this line. The climate of the basin is humid and tropical, although at places extremes of heat and cold are often encountered. In a year, four distinct seasons occur in the basin. They are: (i) cold weather, (ii) hot weather, (iii) south-west monsoon and (iv) post-monsoon.

Rainfall

According to the records maintained by the India Meteorological Department, there were ten rain-gauges in 1867 in the entire Narmada basin. The number rose to 21 rain-gauges in the year 1891, the year from which published rainfall data are available. Thereafter, there has been a steady growth of the rain-gauge network in the basin. The number of raingauge stations in the basin was 205 in 1980. Of these, nearly 120 raingauge stations have data for more than 40 years. About 50 self-recording raingauge stations (SRRG) are maintained by IMD or other agencies like the flood forecasting division of CWC, state irrigation departments, etc.

The normal annual rainfall for the basin works out to 1,178 mm. South-west monsoon (June to October) is the principal rainy season accounting for nearly 94% of the annual rainfall. About 60% of the annual rainfall is received during July and August months. Table 11.6 shows the monthly distribution of normal annual rainfall in the basin. The rainfall is heavy in the upper hilly and upper plains areas of the basin. It gradually decreases towards the lower plains and the lower hilly areas and again increases towards the coast and southwestern portions of the basin. The annual rainfall in the upper part of the catchment is more than 1400 mm and in some pockets it exceeds 1,650 mm. From the source to Sardar Sarovar dam, the coefficient of variation varies from 19% to 37%.

Monthly Distribution of Normal Annual Rainfall

Month

Rainfall (mm)

Percent of Annual Rainfall

June

152.4

July

392.4

August

314.8

September

199.7

October

40.6

3.4

Non-monsoon months

78.1

6.6

Total

1,178.0

100.0

Seasonal Normals of Rainfall (cm) for Narmada Basin

Jan-Feb

Mar-May

Jun-Sep

Oct-Dec

Rainfall (cm)

No. of Rainy days

Rainfall (cm)

No. of Rainy Days

Rainfall (cm)

No. of Rainy Days

Rainfall (cm)

No. of Rainy Days

2.9

2.7

110.8

6.7

Average Monthly Rainfall for Selected Stations in Narmada Basin.

City

Elevation

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Bhopal

501 m

6.0

4.0

9.0

6.0

14.5

173.5

501.0

278.0

265.0

42.0

26.0

5.0

Indore

564 m

6.0

4.0

2.0

3.0

13.0

147.0

282.0

207.0

164.0

31.0

15.5

7.0

Temperature

In cold weather, the mean annual temperature varies from 17.5°C to 20°C and in hot weather from 30°C to 32.5°C. In the south-west monsoon, the temperature ranges from 27.5°C to 30°C. In the post-monsoon season, temperatures range from 25°C to 27.5°C.

Maximum and Minimum Temperature for a few cities in/near Narmada Basin

City

Elevation

Max/Min

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Ahmedabad

56 m

Max

28.7

31.0

35.7

39.7

40.7

38.0

33.2

31.8

33.1

35.6

33.0

29.6

Min

11.9

14.5

18.6

23.0

26.3

27.4

25.7

24.6

24.2

21.2

16.1

12.6

Bhopal

501 m

Max

25.7

28.5

33.6

37.8

40.7

36.9

29.9

28.6

30.1

31.3

28.5

26.1

Min

10.4

12.5

17.1

21.2

26.4

25.4

23.2

22.5

21.9

18.0

13.3

10.6

Evaporation

Little data on evaporation is available in the basin. There are a few agro-meteorological observatories located in the basin.

Monthly Potential Evaporation for Kolar Sub-basin in Narmada Basin

Month

Evaporation Depth (m)

Month

Evaporation Depth (m)

January

0.125

July

0.256

February

0.14

August

0.137

March

0.175

September

0.167

April

0.278

October

0.146

May

0.45

November

0.128

June

0.306

December

0.093

Water Resources of Narmada Basin

Stream Gauging Network

Systematic observations of gauge and discharge were started in Narmada basin only in 1947 by the then Central Waterways, Irrigation and Navigation Commission. The main river Narmada is now gauged at nine sites at Manot, Mandla, Jamtara, Bermanghat, Hoshangabad, Mortakka, Mandleshwar, Barwani, and Garudeshwar, where daily gauge and discharge observations and hourly gauge observations during monsoon season (June-Oct.) are made. Only a few principal tributaries in the Narmada are gauged. In addition to the CWC sites, state governments have also established sites to measure streamflows.

Like the peninsular rivers of India, the Narmada rises in the latter half of June and the flow reaches its maximum in the months of August and September. Thereafter, it begins to fall in October and reaches its lowest level just before the monsoon. A quick glance of observed data shows that a maximum flow of 39,644 cumec was recorded at Garudeshwar on the 17th of September, 1950 and a minimum of 10.3 cumec on the 10th June 1952.

Surface Water

The surface water potential of the Narmada river system has been assessed at different times by different authorities. In 1949 when the basinwise water resources of the country were assessed on the basis of Khosla's formula, the annual runoff of the Narmada river system was estimated to be 49,241 MCM.

In 1960, the total annual runoff of the Narmada river system was assessed as 40,088 MCM. In 1965, the Narmada Water Resources Development Committee, set up by the Government of India, reported the total annual runoff of the Narmada River system at Garudeshwar site as 44,331 MCM. Table 11.14 summarizes the annual observed runoff in selected tributaries of Narmada.

Annual Average Observed Runoff at Selected CWC Sites in Narmada Basin

Name of the site

Name of the Stream

Catchment Area (km²)

Annual Average Runoff (BCM)

Garudeshwar

Narmada

87,892

35.4

Rajghat

Narmada

77,674

31.3

Mandleshwar

Narmada

72,809

32.7

Handia

Narmada

54,027

26.1

Hoshangabad

Narmada

44,548

22.6

Sandia

Narmada

33,954

17.1

Barmanghat

Narmada

26,453

13.0

Jamtara

Narmada

17,157

10.1

Bijora

Narmada

14,561

7.5

Mortakka

Narmada

67,184

24.7

The 75% dependable flow in the basin has been assessed at 34,537 MCM or 28 MAF by the Narmada Water Disputes Tribunal. On this basis, the shares of the four party States in this quantity were fixed as: M.P. 18.25 MAF (22,511.01 MCM), Gujarat 9 MAF (11,101.32 MCM), Rajasthan 0.5 MAF (616.74 MCM) and Maharashtra 0.25 MAF (308.37 MCM). The runoff factor for the 75% dependable flow worked out to be 0.29.

Hydroelectric Power

The hydroelectric power potential of the basin has been assessed as 2,027 MW at 60% load factor. The details about major hydropower and other projects in the basin are given in a later section. There are thermal stations at Jabalpur and Satpura.

Water Quality

As compared to the other rivers, the quality of Narmada water is quite good. Even near the point of origin, the quality of river water was in class ‘C’ in the year 2001 while it was in class ‘B’ in earlier years. As was observed for most other rivers, in case of Narmada also, BOD and Total Coliform are critical parameters.

Desired and Existing Water Quality Levels for Narmada

Location

Desired class

Observed class & critical parameters

1997

1998

1999

2000

2001

Narmada near source at Amarkantak, M.P.

B
DO, BOD

B
DO

C
DO, Totcoli

Narmada at Mandla near road bdg., MP

Narmada at Sethanighat, M.P.

D
BOD, Totcoli

C
Ph, Totcoli

D
BOD, Totcoli

Narmada at Narsinghpur, M.P.

D
BOD

Narmada at Hoshangabad U/S, M.P.

C
Totcoli

C
pH, Totcoli

C
Totcoli

D
BOD, Totcoli

C
Totcoli

Narmada at Hoshangabad D/S, M.P.

D
BOD, Totcoli

D
pH, BOD, Totcoli

C
Totcoli

E
pH, Totcoli

D
BOD, Totcoli

Narmada at D/S of Omkareshwar, M.P.

Narmada at Mandleshwar, M.P.

Narmada at Maheshwar, M. P.

Narmada at Badwani, M.P.

Narmada at Garudeshwar, Gujarat

D
BOD, Totcoli

C
Totcoli

Narmada at Chandod, Gujarat

Narmada at Panetha, Gujarat

Narmada at Bharuch, Zadeshvar, Gujarat

D
BOD

* NA- Not Available. Source: www.cpcb.nic.in.

Major Water Resource Projects

Prior to the independence, there was no large-scale development of Narmada water, partly because the region was not subject to any serious famines. Only a few medium projects, with total irrigation potential of about 40,500 ha, existed in the basin.

The Master Plan on the utilization of the Narmada waters was submitted to Khosla Committee by the Madhya Pradesh Government. It proposed that by constructing 19 dams on Narmada and its tributaries, irrigation can be provided to 3.1 million ha area by utilizing 29,295 MCM of water. The Rajasthan State, whose desert areas in Barmer and Jalore districts are close to the tail reaches of the (then proposed) high level Narmada Canal, requested the Committee to allocate the Narmada waters for irrigating more than 0.4 million ha falling in their State. Subsequently, a list of 31 major projects was finalized for the Narmada basin.

Thirty-One Projects Envisaged in the Narmada Basin

S. N.

Name of Project

Catchment

Area (km²)

State

River

Status

Upper Narmada

1,243

Narmada

Proposed

Raghavpar (Hydel)

6,160

Narmada

Proposed

Rosa (Hydel)

4,312

Narmada

Proposed

Upper Burhner

1,606

Narmada

Proposed

Halon

715

Narmada

Proposed

Basania (Hydel)

9,583

Narmada

Proposed

Dhobatoria

1,854

Narmada

Proposed

Matiyari

159

Narmada

Proposed

Bargi

14,556

Narmada

Completed

Ataria

554

Narmada

Proposed

Chinki

22,414

Narmada

Proposed

Sher

881

Narmada

Proposed

Machrewa

470

Narmada

Proposed

Shakkar

1,479

Narmada

Proposed

Sitarewa

202

Narmada

Proposed

Dudhi

808

Narmada

Proposed

Barna

1,176

Barna

Completed

Tawa

5,983

Narmada

Completed

Kolar

508

Kolar

Completed

Morand

1,041

Narmada

Proposed

Ganjal

436

Narmada

Proposed

Sukta

469

Narmada

Completed

Chhota Tawa

969

Narmada

Proposed

Indira Sagar

61,642

Narmada

Proposed

Omkareshwar (Under Construction)

64,880

Narmada

Proposed

Maheshwar (Under Construction)

69,184

Narmada

Proposed

Upper Beda

544

Narmada

Proposed

Man

690

Narmada

Proposed

Lower Goi

1,119

Narmada

Proposed

Jobat

792

Narmada

Proposed

Sardar Sarovar (Under Construction)

88,000

Narmada

Proposed

Utilisation by Major Water Resources Projects in Narmada Basin, MP.

S. N.

Category

Area to be Irrigated (Lakh ha)

Water Used

(M.A.F)

Million Cubic m

29 Major Projects

14.15

11.35

14,000

135 Medium Projects

6.7

2.89

3,562

3000 Minor Projects

6.7

2.51

3,100

Total

27.55

16.75

20,660

Domestic & Industrial use

1.5

1,850

Grand Total

27.55

18.25

22,511

Floods, Water Logging and Drainage

In Madhya Pradesh, Narmada flows in a deep channel with high banks, which are not frequently over-topped. Below the Hiranphal-Navagam gorge, Narmada spreads out over the flat Gujarat plains and flows as a wide stream with low banks for the rest of its course down to the Gulf of Cambay. Floods do occur frequently in this reach and cause damage to life and property.

Regional flood frequency analysis of two hydro-meteorological sub-zones of zone 3, namely (i) Lower Narmada and Tapi sub-zone 3(b); and (ii) Upper Narmada and Tapi sub-zone 3(c), was carried out by NIH). Long term annual maximum peak flood data records and areas of various bridge sites under these sub-zones formed inputs to these studies.

Salient Features of Various Catchments of the Sub-Zones 3(b) and 3(c)

Sub-Zone

Area of Sub-Zone (km²)

Number of Bridge Sites in the Sub-Zone

Range of Catchment Area of Bridge Sites (km²)

Range of Mean Annual Peak Flood(m³/s)

Range of Record Length (Years)

3 (b)

77,000

17.22 - 1017.00

34.95 - 558.29

12 - 28

3 (c)

86,353

41.80 - 2110.85

111.95 - 1730.53

14 - 30

Flood Control by Reservoirs in Upper Narmada Basin

The runoff factor for the 75% dependable flow of Narmada works out to be 0.29. The annual rainfall in the upper part of the Narmada catchment is more than 1,400 mm and in some pockets it exceeds 1,650 mm. The Narmada catchment up to Hoshangabad received unprecedented rainfall in 1999. In the catchment up to Hoshangabad, three major dams have been constructed: Bargi, Barna and Tawa. Consequently, a large part of the Hoshangabad city remained flooded for considerable time, causing severe damages.

The observed discharges at Hoshangabad during September 18-23 were in the vicinity of 25,000 cumec and this high flow has caused flooding in the city and severe damages. The discharge at Sandia was probably higher than this; Indian Institute of Tropical Meteorology, Pune. Daily rainfall depths exceeding 180 mm have taken place in this storm.

As noted above, the live storage capacity of the Barna dam is very small and no significant control of flood is possible by regulation of this dam. The catchment area at Bargi dam is 14,556 sq. km, at Tawa 5,983 sq. km and the free catchment up to Hoshangabad is 23,337 sq. km.

In the worst case scenario when one-day PMP takes place over the entire catchment, the flow at Hoshangabad would be 222,000 cumec. In case the rain is over the catchment of Tawa and Bargi the flow at Hoshangabad will be 102,946 cumec. Similar calculations were carried out for the rainfall at the rate of 90% of PMP etc. It was found that when the one-day rainfall is about 25% of PMP and it takes place only over the Tawa and Bargi catchments, the flow at Hoshangabad would be close to 25,700 cumec which is of the same order as the discharge experienced in the September 1999 floods. It is also seen that if this rainfall (15 cm) in one day takes place over the intermediate catchment, it will lead to peak discharge over 42,500 cumec which, when routed, would give a peak discharge of 29,779 cumec at Hoshangabad.

The volume under the discharge hydrograph at Hoshangabad during September 11-23, 1999 was 18,455.6 MCM. Compared to this, the combined live storage capacity of Bargi (3,180 MCM) and Tawa (2,050 MCM) is 5,230 MCM. Therefore, even if the entire live storage of both these dams is available for moderation of floods, the floods that were experienced in September 1999 cannot be significantly moderated and very few options are available in such an eventuality. It is also important to note that the free catchment area at Hoshangabad is 23,337 sq. km.

The following measures can be considered to manage the flooding problem at Hoshangabad city:

1. It would be necessary to install and operate a flood forecasting system for the basin. This will help in efficient utilization of the available storage space in the dams for flood moderation. Based on the forecasts, reservoir levels can be pre-depleted to make available additional space to regulate the floods.

2. A warning system to issue flood warnings sufficiently in advance needs to be put in place so that the damages to life and movable property can be minimized.

3. Options to increase the carrying capacity of river channel at critical locations should be explored.

4. The construction of embankments at selected locations will help in protecting the vulnerable areas.

It would be necessary to create additional storage space in the basin in the light of the award of NWDT.