A Study on availability and sharing of cauvery waters during distress years

A STUDY ON AVAILABILITY AND SHARING OF
CAUVERY WATERS DURING DISTRESS YEARS
BY
SANJAY K N
M-Tech II SEM, Hydraulics
USN: 4NI15CHY14
UNDER THE GUIDANCE OF
DR. K. C. MANJUNATH
DR. R. YADHUPATHI PUTTY

CONTENTS
• INTRODUCTION
• LITERATURE REVIEW
• METHODOLOGY
• RESULTS AND DISCUSSIONS
• CONCLUSIONS AND RECOMMENDATIONS
• REFERENCES
2

Introduction
Over View of the Basin
• The Cauvery basin extends over states of Tamil Nadu, Karnataka, Kerala
and Union Territory of Puducherry, draining an area of 81,155 km²
which is nearly 2.7% of the total geographical area of the country.
• Out of this, 42% of area lies in Karnataka, 54% of area in Tamil Nadu &
Karaikkal region of Puducherry and 4% of area in Kerala. It falls in
peninsular India and lies between 75°27‟E to 79°54‟E and 10°9‟N to
13°30‟N.
• It is bounded by the Western Ghats on the west, by the Eastern Ghats on
the east and south, and by the ridges separating it from Krishna basin
and Pennar basin on the north.
• The Cauvery is the fourth largest river in the Peninsular India flowing
east and draining into the Bay of Bengal.
• The total length of the river from the source to its outfall in Bay of
Bengal is about 800 km of which 320 km is in Karnataka, 416 km in
Tamil Nadu and 64 km in the common boundaries between Karnataka
and Tamil Nadu
3

Over View of the Cauvery Basin
4

Course of River Cauvery and its Tributaries in Karnataka
• The Cauvery River is one of the major rivers of the peninsular India. It rises at an
elevation of 1,341 m at Talakaveri on the Brahmagiri range near Cherangala
village of Kodagu district of Karnataka and drains into the Bay of Bengal.
• The total length of the river from origin to outfall is nearly 800 km. In size, it is
smaller than the Godavari, the Mahanadi and the Krishna.
• The tributaries of the river Cauvery include Kanaka, Hemavathi, Shimsha,
Arkavathi, LakshmanThirtha, Kabini and Suvarnavati in Karnataka and Bhavani,
Noyyal and Amaravathy in Tamilnadu.
• The river Hemavati originates near Belur at an altitude of 1500 m, flowing
southeast and joins with its tributary namely Yagachi near Gorur. From Gorur the
Hemavathi flows east-south and finally joins the river Cauvery.
5

• Kabini is an important tributary which originates in the Western Ghats in Kerala
state at latitude of 2060 m and joins the river Cauvery near T. Narsipura.
• The other tributary Lakshmanthirtha originates near Kurichi at an elevation of
about 1,500 m and flows northeast and joins river Cauvery at Krishna Raja Sagar
Lake.
• Another important tributary, Suvarnavathi joins the river just before the
Sivasamudram falls. After a much tumulus course the river maintains Southeast-
East direction but with a number of curves producing rapids and falls, till it
Reaches Sivasamudram falls.
• The rivers, Bhavani and Moyar drain from Nilgiris. But the tributaries, Noyyal
and Amaravathi which originate from Karimalai (1966 m) and Anaimudi area of
Western Ghats are important in the southern part of the Cauvery basin.
6

Lengths of Major Tributaries
Sl No River Name Length (km)
1 Cauvery River 825.10
2 Amaravati River 215.15
3 Arkavati River 169.82
4 Bhavani River 234.98
5 Hemavati River 233.63
6 Kabini or Kapila River 237.61
7 Lakshmantirtha River 148.82
8 Noyil River 181.49
9 Perum Pallam 197.32
10 Shimsha River 204.23
7

Topography
• The maximum elevation of about 2000-3000 m is observed in 1% of the total
geographical area of the basin.
• Around 32% of the basin area falls under the 750-1000 m elevation zone
• The hills forming the western limits of the basin extend from the past “Bisley
Ghat" to the "Jenkle Betta" and includes peaks like "Puspagiri" or "Subramanya"
close to the South-West border rising to a height of 1715 m.
• Besides Jenkle Betta at 1389 m, Devara Betta which raises to up to a height of
1282 m and Murukanagudda at 1300 m.
• Indra Betta in Hassan district is 1020 m high and is noted for 52 feet colossal
statue of "Gommateshwara" on its summit.
8

Climate
• Climate is a measure of the average pattern of variation in temperature, humidity,
atmospheric pressure, wind, precipitation, atmospheric particle count and other
meteorological variables in a given region over long periods of time.
• Climate is different than weather, in that weather only describes the short-term
conditions of these variables in a given region.
• In the Cauvery basin, four distinct seasons occur. They are winter, summer,
South-West Monsoon, and North-East Monsoon.
• There is a considerable variation in the mean daily maximum and minimum
temperatures across the basin.
• The South-West monsoon sets by middle of June and ends by middle of
September. During this season the basin receives major part of its total annual
rainfall.
• The North-East monsoon is from October to December and is important
particularly for the Eastern part of the basin.
9

Rainfall
• There are 224 existing rain gauge stations (Reporting to India Meteorological
Department) inside the Cauvery basin. These rain gauge stations are more or less
uniformly distributed over the entire basin and their number is fairly adequate
• The rainfall in the basin varies from region to region
• The normal annual rainfall in Kerala region is about 2400 mm. In the Western
Ghats it ranges from 1700 mm to 3800 mm
• In general, the highest rainfall in the Cauvery basin usually occur in July or early
August and the mean annual rainfall is 1075 mm.
• The basin is mainly influenced by South-West monsoon in Karnataka & Kerala
and North-East monsoon in Tamil Nadu.
• Most of the parts in Tamil Nadu receive rainfall from the North-East Monsoon
10

Temperature
• The basin has a tropical and sub-tropical climate. In the Upper reaches (i.e.,
Kerala and Karnataka), the variation in temperature is very small. The mean
monthly temperature over the basin varies from 22.98° C to 28.43° C
• The monthly average mean temperature (1971-2004) is 25.75° C. Temperatures
are higher in the plains (lower reaches) than in the hills (upper reaches)
• The mean temperature (Mean of Max. and Min.) in Kerala is below 20°C and in
Karnataka it ranges between 20°C to 26°C
• The mean temperature in Tamil Nadu is between 26° C to 30° C
• The overall mean maximum temperature for the Cauvery basin is 30.56°C and
mean minimum temperature is 20.21°C
11

Land Use/Land Cover
• It is found that nearly 21 land use/land cover classes exist in the basin.
Agricultural land is dominant in this basin having an area of 53736.30 sq. km.
(66.21%) followed by 16636.66 sq. km. of forest area (20.50%)
• The built up area is 4.01% which comprises of 3256.37 sq.km of the total area of
the basin. 3133.94 sq. km. wastelands are there in this basin comprising 3.86% of
the total basin area
• The second level categories of land use/land cover in the basin are fallow land,
scrub land, scrub forest, river/stream/canal, rural, urban mining,
swamp/mangrove, etc
• The land use pattern of the basin witnessed a change in last few decades
• The fast growing population aided with the modern technology lead to rapid
change in the land use pattern of the basin
• The forest area has been decreasing due to the encroachment for agricultural land
12

Cauvery Land Use Land Cover
13

Cropping Pattern
• There are mainly three crop seasons in the basin viz. kharif, Rabi. The
kharif crops are paddy, bajra, jowar, maize, ragi, cotton, millets etc
• Paddy is the most important crop in this basin, whereas Ragi, Jawar and
other millets constitute the important crops under rain fed conditions.
• Coconut, betel leaves, pepper, oranges and lemon are grown as horticulture
crops throughout the year
• The main forest products are sandalwood, bamboo, teak, eucalyptus, blue
gum and wattle etc
• However under irrigation area, rice and sugarcane are the main crops. In
Tamil Nadu, rice is the major crop and especially after the construction of
the Mettur dam two crop systems is practiced
• This two crop system is cultivated in an area of 30% to 40% of the delta
and in the remaining area a long duration single crop of rice is cultivated.
• According to report of the National Commission on Agriculture (1976)
nearly 71% of the irrigated crop area in Tamil Nadu is under rice
14

Distress Sharing
• During the normal rainfall years, there are no problems with the allocated water
by the tribunal.
• If the monsoon fails there is distress and the allocated states face a huge problem
due do decrease in the available yield.
• In such cases the Tribunal had stated that distress will be shared „proportionately‟.
It doesn‟t mention any distress formula. This continues the dispute without any
solutions
Need for the present study
• The issue associated with apportionment was the question of distress sharing –
how water would be distributed in a distress year when monsoons failed, reducing
the available surface flow of the river
• The issue became particularly significant after the crisis of 1995-1996 where the
rains failed in Karnataka resulting in an acute shortage of water and rendering the
state unable to release the amount dictated by the interim order to Tamil Nadu
• The absence of any form of a distress sharing formula in the interim order has led
unreasonable burden of releasing almost all available water to Tamil Nadu from
the reservoirs of Karnataka
15

OBJECTIVES
• Collection of surface hydrological information and to study rain
fall trend analysis in the Cauvery basin of Karnataka.
• Collection of discharge data from the gauging stations in the
Cauvery basin of Karnataka and to study the discharge data for
the past four decades.
• To suggest a distress sharing arrangement of Cauvery river
water between Karnataka and Tamil Nadu for rainfall deficit
years.
16

SCOPE OF THE WORK
• Scope of the work includes collection of rainfall and the discharge data from
different departments like Water Resource Development Organisation (WRDO),
Directory of Economics and Statistics (DES), and INDIA WRIS.
• The study includes anomaly analysis, rainfall pattern, return period calculations of
five and ten year rainfall magnitude of distress years.
• Yield calculation carried out through the SCS-CN method in the plain areas and
the regionally developed RF-RO model used in the Western Ghats areas of the
Cauvery basin for the collected rainfall data, discharge variations in the gauging
stations, and finally developing an acceptable approach to share water during
distress years.
17

Although plenty of interstate and international river water disputes exist in
different parts of the world limited information is available on sharing of
such river waters and also rational approach to share the scarce water
between the states or nations. Hence few guidelines were evolved in 1966
at Helsinki, Finland to share water between the contesting states or
countries.
An Overview of the Helsinki Water Convention
• The geography of the basin, including in particular the extent of the
drainage area in the territory of each basin State;
• The hydrology of the basin, including in particular the contribution of
water by each basin State;
• The climate affecting the basin;
• The past utilization of the waters of the basin, including in particular
existing utilization;
19

• The economic and social needs of each basin State;
• The population dependent on the waters of the basin in each basin
State;
• The comparative costs of alternative means of satisfying the economic
and social needs of each basin State;
• The availability of other resources;
• The avoidance of unnecessary waste in the utilization of waters of the
basin;
• The practicability of compensation to one or more of the co-basin
States as a means of adjusting conflicts among uses; and
• The degree to which the needs of a basin State may be satisfied,
without causing substantial injury to a co-basin State.
20

Inter-state River Water Disputes In South India
Richards and Singh (2001) argue that Indian water-dispute settlement mechanisms are
ambiguous and opaque. They distinguish analytically between situations where
cooperation is possible, and situations of pure conflict, where the initial allocation of rights
is at stake. In the latter case, a search for a negotiated solution may be futile, and quick
movement to arbitration or adjudication may be more efficient.
However, in India, the process is slow, and effectively binding arbitration does not exist.
The entanglement of inter-state water disputes with more general centre-state conflicts and
political issues compounds problems.
They argue that these impacts can be reduced by a more efficient design of mechanisms
for negotiating inter-state water disputes
21

Krishna-Godavari Water Dispute
• The Krishna-Godavari water dispute among Maharashtra, Karnataka, Andhra
Pradesh (AP), Madhya Pradesh (MP), and Orissa could not be resolved through
negotiations.
• Here Karnataka and Andhra Pradesh are the lower riparian states on the river
Krishna, and Maharashtra is the upper riparian state. The dispute was mainly about
the inter-state utilization of untapped surplus water
• The Godavari Tribunal commenced hearings in January 1974, after making its award
for the Krishna case. It gave its final award in 1979, but meanwhile the states
continued negotiations among themselves, and reached agreements on all disputed
issues
• Unlike in the case of other tribunals, there was no quantification of flows, or
quantitative division of these flows: the states divided up the area into sub-basins,
and allocated flows from these sub-basins to individual states – this was similar in
approach to the successful Indus agreement between India and Pakistan.
22

The Cauvery Dispute
• The core of the Cauvery dispute relates to the re-sharing of waters that are already
being fully utilized.
• The two parties to the dispute are Karnataka (old Mysore) and Tamil Nadu (the old
Madras Presidency). Between 1968 and 1990, 26 meetings were held at the
ministerial level but no consensus could be reached.
• The Cauvery Water Dispute tribunal was constituted on June 2, 1990 under the ISWD
Act, 1956
• There has been a basic difference between Tamil Nadu on the one hand and the central
government and Karnataka on the other in their approach towards sharing of Cauvery
waters
• The most difficult Ganga water dispute between India and Bangladesh was resolved
through Ganga water treaty in 1996.
• If India and Bangladesh, India and Pakistan could successfully resolve their dispute
over the river waters, there is no reason why a dispute between states within the
Indian union cannot be settled amicably.
23

Origin of the Cauvery Dispute
• The dispute relating to the sharing of the Cauvery water between Karnataka and Tamil
Nadu is a very old dispute.
• The Cauvery water dispute differs from other major river water disputes in India,
including those relating to the Narmada, the Krishna and the Godavari.
• While these disputes were mainly about the inter-state utilisation of hitherto untapped
surplus waters, the dispute in the case of the Cauvery relates to the re-sharing of
waters that are already being almost fully utilised in their totality.
• The State of Tamil Nadu has been using Cauvery waters right from ancient times. It
has been mentioned in "SHABDA MANI DARPANA” a Kannada Grammar Book,
dating back to 13th century
24

The 1892 Agreement
• The Agreement is entitled, "Rules defining the limits within which no new irrigation
works are to be constructed by Mysore State without previous reference to Madras
Government
• The 1892 Agreement made it practically obligatory for Mysore to obtain prior
consent of the then Madras Presidency before taking up any irrigation works.
• No corresponding restrictions were imposed on Madras
• The Mysore Government desires to construct any "New Irrigation Reservoir" or any
new Anicut requiring the previous consent of the Madras Government under the last
preceding rule
• The information regarding the proposed work shall be forwarded to the Madras
Government and the consent of the Government shall be obtained previous to the
actual commencement of work.
25

The 1924 Agreement
• Mysore Government may construct KRS reservoir to a height of 124 ft above the
river bed and to an effective capacity of 44.827 TMC ft to irrigate 1.25 lakh acres.
• Mysore Government agrees to regulate discharges through and from KRS reservoir
strictly in accordance with the rules and regulations which forms part of this
Agreement
• There should be mutual exchange of returns of technical details and extension of
irrigation at the close of each official year
• In case of a dispute between the two Governments touching the interpretation or
operation or carrying out this Agreement, such a dispute shall be referred to
arbitration or to Government of India, if both parties agree for settlement
26

Expiry of the Agreement of 1924
• The Government of Karnataka interpreted the above as a statement of the expiry of the
entire agreement and that, after a period of 50 years, none of its clauses were
enforceable
• The Government of Tamil Nadu, on the other hand, asserted that the agreement was
permanent in nature
• The Tribunal instead recommended a consideration of the terms of the agreement while
evaluating the developments made in different states for the equitable share
27

Cauvery Water Disputes Tribunal Final Order
Sl No Name of the State Quantity of Water in TMC
1 Kerala 30
2 Karnataka 270
3 Tamil Nadu 419
4 U.T. of Pondicherry 7
State wise Water Allocated by the Tribunal
MONTH TMC MONTH TMC
June 10 December 8
July 34 January 3
August 50 February 2.5
September 40 March 2.5
October 22 April 2.5
November 15 May 2.5
192TMC
Monthly Wise Water Allocations to Tamil Nadu from Karnataka
28

States
TamilNadu
Karnataka
Kerala
Puducherry
Total
Basin area up to lower
Coleroon Anicut site
(in km2)
44,016
(54%)
34,273
(42%)
2,866
(4%)
-
(0%)
81,155
Inflow from basin in
TMC
252
(32%)
425
(54%)
113
(14%)
- -
Share for each state as
per tribunal verdict of
2007 in TMC
419
(58%)
270
(37%)
30
(4%)
7
(1%)
726
Basin Area of each State and Inflow from each Basin
29

WATER DISPUTES ACTS
Inter States Water Disputes Act, 1956
It was enacted by the Parliament under Article 262 of the Constitution for adjudicating disputes
relating to waters of Inter-State Rivers of river valleys
Salient Features
• Constitution of the tribunal
• The Tribunal shall have the same powers as are vested in a civil court
• Power to make schemes for implementing decisions of tribunal
• Dissolution of Tribunal and power to make rules
• Adjudication of water disputes
• Maintenance of data bank and information
• Bar of jurisdiction of Supreme Court and other Courts
31

The River Boards Act, 1956
It was enacted under Entry 56 of List I of the Constitution of India for the establishment of
River Boards for the regulation and development of Inter State Rivers and River valleys.
Salient Features
• It undertake preliminary investigation or surveys
• Power of Inspection of any works undertaken by any Government interested
concerning the regulation or development of the Inter-State River or river valley
• It can conduct and co-ordinate research on various aspects of the conservation,
regulation or utilization of water resources
• It can publish statistics or other information relating to the regulation or
development of the Inter-State River or river valley
These two acts were introduced by government in 1956 to resolve the dispute of sharing
the water of Interstates Rivers.
32

Seligman (2011) made a comparison of the way India and the United States address
disputes on interstate rivers. In US there are no federal statues on water disputes
Features India United State
Federation of States Yes Yes
The Constitution Yes Yes
Supreme Court Yes Yes
Common Law Yes Yes
Contracts Between States Yes Yes
Federal Statutes on Water Disputes Yes No
Checklist of Key Features of the Legal Systems in India and the US
33

RAINFALL TREND ANALYSIS
• Wing H et al (2008) studied and investigated the temporal dynamics of rainfall and its spatial
distribution within Ethiopia.
• Changes in rainfall were examined using data from 134 stations in 13 watersheds between
1960 and 2002. The variability and trends in seasonal and annual rainfall were analysed at the
watershed scale. Similar analyses were also performed at the gauge, regional, and national
levels.
• The gauge level analysis showed that certain gauge stations experienced recent changes in
rainfall; these trends were not reflected at the watershed or regional levels.
34

• Jain and Kumar (2012) studied trends in rainfall, rainy days and temperature over
India.
• Sen‟s non-parametric estimator of slope has been frequently used to estimate the
magnitude of trend, whose statistical significance was assessed by the Mann–
Kendall test.
• Spatial units for trend analysis vary from station data to sub-division to sub-basin/
river basins.
• In a study on basin-wise trend analysis, 15 basins had decreasing trend in annual
rainfall
• Among six basins showing increasing trend, one basin showed significant positive
trend. Most of the basins had the same direction of trend in rainfall and rainy days at
the annual and seasonal scale.
35

Bhuvaneswari et al in their study considered daily-observed gridded data of precipitation
at 0.50 by 0.50 resolutions obtained from the India Meteorological Department (IMD for
deriving the baseline (1971–2005) rainfall data to determine the rainfall scenario in future
over Cauvery Basin in India
Sub divisions of Cauvery Basin
For the analysis, the entire Cauvery basin was
divided into five smaller basins viz., Basin 1
(Upper Cauvery up to Mettur reservoir),
Basin 2 (Bhavani basin from Mettur to Upper
Anicut), Basin 3 (Amaravathy basin), Basin 4
(Upper Anicut to Grand Anicut) and Basin 5
(Downstream of Grand Anicut, including
lower Anicut and the delta region).
36

South West Monsoon Rainfall
• The SWM rainfall distribution over Cauvery basin in baseline, mid and end
century.
• In the baseline, most of the regions in Cauvery receive about 350–500 mm of
rainfall during south west monsoon (SWM).
• In the mid-century, the SWM rainfall quantity in the upper Cauvery would increase
by 29% compared to baseline.
• In basin 2 (Bhavani) and basin 3 (Amaravathi) the SWM rainfall in the mid-century
would be higher by 10 and 12% respectively compared to baseline. Similarly, in
basins 4 and 5 (Grand anicut and Delta portion), it is expected to increase by 8.5
and 6% respectively.
• In the end century, the upper Cauvery basin (Basin 1) is expected to receive 41%
more rainfall during SWM than in the baseline. Basins 2, 3 and 4 (middle Cauvery
comprising Bhavani, Amavaravathi and Grand anicut) is predicted to receive about
14, 17 and 16% higher SWM rainfall than the baseline.
37

Rani and Shreedhar (2014) carried out a rainfall analysis in the Belgaum district is
among the 30 districts of Karnataka, situated in the Northwest part of the state.
• Nearly 95% of the annual rainfall is received during the period April to October,
because of the South-west monsoon.
• The work was carried out with annual rainfall data recorded on 42 stations.
Trend Analysis of Rainfall Data is carried out by the following methods
• Mann-Kendall test
• Spearman rho test
• Linear regression
• Relative variability
• Co-efficient of variation
38

• The average annual rainfall of the raingauge stations in Belgaum district ranges
from 346 mm (sarapur) to 5976 mm (kanakumbi) indicating a wide variation from
one station to the another station.
• It is observed that the maximum variation in the annual rainfall occurs at station
Bugate alur with a coefficient of variation of 47% and minimum at the station
hidkal dam with a coefficient of variation is around 18%.
• The average coefficient of variation is around 30% indicating the rainfall varies
reasonably from one year to the next.
• The skewness coefficients for most of the stations are positive indicating that the
low rainfall happens frequently whereas the high value rainfall happens rarely.
• For some of the stations the skewness coefficient is equal to or nearly equal to zero
indicating the data follows a normal distribution.
39

CLIMATE CHANGE AND ITS EFFECT ON RAIN FALL
• Global warming is a widely used term which delivers a sensational message of
increasing temperature of the planet earth.
• This claim does not base on any hypothesis rather a fact driven from thousands of
meteorological measurements all around the globe covering both land and sea
surfaces.
• Precipitation is the most important natural hydrologic event and is a unique
phenomenon varying both in space and time.
Priyadarshini et al (2015) carried out studies to decipher the impact of climate change
on water resources and cropping pattern in Karnataka using the secondary data. Tabular
analyses have been used to derive valid conclusions. The two important river basins of
the state, Krishna and Cauvery, were selected for their study.
40

Cauvery basin
Precipitation: On an average, a slight decrease in precipitation annually in the Cauvery basin.
There is a decrease in precipitation in the monsoon season, an average of around 0.25 per
cent.
Runoff : There is an annual increase in run off. The average annual increase in runoff is
around 0.25 per cent. The runoff increases during the monsoon season, an average of around
2.25 per cent.
The decrease in evapotranspiration and the increase in runoff is a cause of concern,
contributing to the uncertainty about the yields in the future in the Cauvery basin.
Krishna basin
Runoff: There is an increase in annual runoff in the Krishna basin, the percentage increase in
runoff annually, is on an average 3 per cent.
Evapo-transpiration: There is a decrease in the rate of evapotranspiration in the Krishna
basin.
The results of the assessment of the impact of climate change on the Cauvery basin indicates
that decrease in precipitation in the basin.
41

The Meaning of Equitable Apportionment
Equitable apportionment” is the term commonly used to denote the division of water
among competing parties. It is usually a slow and sometimes contentious process that
involves hydrology, economics, engineering, law and sometimes the resolution of
ethnic politics or historical claims from decades ago
• The States can divide the water by territory or by the amount of flow that each State
contributes.
• The States can divide the water based on historical claims. A State that has
traditionally used 60% of the water in the river in the past can assert a claim based
on prior diversions
• The States can divide the water based on a priority of uses. Irrigation and
municipal (domestic) supply, for example, could take priority over industrial uses
and navigation, or vice versa. Environmental protection – water for a river delta to
sustain fisheries, for example – could receive higher or lower protection depending
on the value the States place on ecological (and related economic) benefits
42

Level of Dependability
One of the most controversial decisions by the Tribunal was the estimation of the yield of
the Cauvery at a dependability of 50 per cent
State
Yield on 50 %
Dependability
Yield on 75 %
Dependability
Karnataka 392 (53%) 355 (53%)
Tamil Nadu and Pondicherry 222 (30%) 201 (30%)
Kerala 126 (17%) 114 (17%)
Total 740 TMC 670 TMC
Yield in the Cauvery basin 1934-1972
43

Summary of Literature Review
• By adopting the suitable parameter and constitution of a committee, mentioned in the
Helsinki convention, the reasonable and equitable sharing of water between the contesting
nations can be solved to a maximum extent.
• In the Krishna-Godavari water dispute, there was no quantification of flows, or quantitative
division of these flows.
• Inter states water disputes act, 1956 was enacted by the Parliament under Article 262 of the
Constitution for adjudicating disputes relating to waters of Inter-State Rivers of river valleys.
• In the upper Cauvery river basin, there will be huge impact of climate change on rainfall
patterns as well as socio-economic condition of the people. For Upper Cauvery river basin
usually the drought intensity was once in four years barring Kodagu district.
• The trend analysis gave both increase and decrease trend for the period during 1981 to 2012.
But 1901 to 1980 there was no trend observed for the rainfall in the upper Cauvery river
basin.
• The States can divide the water based on historical claims. A State that has traditionally used
60% of the water in the river in the past can assert a claim based on prior diversions. The
States can divide the water by territory or by the amount of flow that each State contributes.
44

STUDY AREA
• The Cauvery River is one of the major rivers of India, which is considered sacred
• It is the fourth largest river in the Indian peninsular next only to Godavari, Mahanadi
and Krishna.
• The basin has a drainage area of around 34,273 km2
• The total length of the river from source to its outfall, Bay of Bengal is about 800 km
• Of this, 320 km is in Karnataka, 416 km is in Tamil Nadu and 64 km forms the
common boundary between Karnataka and Tamil Nadu.
Index map of Cauvery basin Sub divisions of Cauvery basin
46

Sl
No
Basin
Name
Catchment
Area in
km2
Sl
No
Basin
Name
Catchment
Area in
km2
1 ARKAVATHI 4161 8 CHIKHOLE AND
SUVERNAVATHI
998
2 SHIMSHA 8664 9 YAGACHI DAM AS
OUTLET
551
3 HEMAVATHI DAM up to
KRS
4900 10 SAKLESHPURAAS
OUTLET
588
4 HEMAVATHI DAM AS
OUTLET
1763 11 KABINI DAM AS OUTLET 445
5 HARANGI KUDIGI AS
OUTLET
1213 12 REMAINING AREA 3319
6 LAKSMANTHIRTHA K M
WADI AS OUTLET
700 13 CAUVERY up to
KHSHALNAGARA
1188
7 KABINI DAM up to
T N PURA
4485 14 LAKSMANTHIRTHA up to
KANOOR BRIDGE
687
15 KRS DAM up to T N
PURA
1338
Sub Basins of Cauvery River with its Catchment Areas
47

Watershed Delineation With ArcGIS Software
• Watersheds, also known as basins or catchments, are physically delineated by the
area upstream from a specified outlet point
• Watersheds can be delineated manually using paper maps, or digitally in a GIS
environment
• ArcGIS can delineate the total area flowing into a given outlet, also called a pour
point, based on a digital elevation model
Kabini up to T Narasipura Chikhole and Suvernavathi basin Shimsha basin
48

COLLECTION OF DATA
Rainfall Data
• Rainfall data for the 97 rain gauge stations available within the Cauvery basin of
Karnataka
• The data were collected from the Water Resources Development Organization
(WRDO) and Directorate of Economics and Statistics (DES)
• The data length of an individual rain gauge station vary from 11 to 79 year
• Most of the stations have 35 year data length
• The annual rainfall over the catchment varies from 134 to 9986 mm
• The maximum rainfall occurred at station Bhagmandala with 9986 mm in the year
1961 in which the minimum occurred at the station Nagmangala with rainfall of
134 mm in the year 2016
Discharge Data
• Hydrological observation in the basin is carried out by the Central and State
Governments.
• The CWC maintains 36 gauge-discharge sites in the basin.
• 8 Gauge Discharge Water Quality (GDQ) and 6 Gauge Discharge Sediment and
Water Quality (GDSQ) observation sites are present in Cauvery basin in Karnataka.
49

Rain gauge stations considered in the Cauvery basin in Karnataka
Index map
50

Hydro observation stations in the Cauvery basin
51

Sl
No
Station
Name
From To
Data Length
in Years
1 Akkihebbala 1999 2014 16
2 Chunchanakatte 2008 2014 7
3 M H Halli 1978 2014 37
4 Sakleshpura 2002 2014 13
5 Thimmanahalli 2000 2014 15
6 K M Vadi 1979 2014 36
7 Muttenkera 1973 2014 42
8 Kudige 1973 2014 42
9 T narasipura 1971 2014 44
10 Kollegala 1971 2014 44
11 Kanakapura 1979 2003 25
12 T Bekuppe 2003 2014 12
13 T K Halli 1978 2014 37
14 Bendrehalli 2005 2014 10
15 Biligundlu 1971 2014 44
List of Hydro Observation Stations in Cauvery Basin in Karnataka
52

Rain Fall Trend Analysis
The various statistical methods used are classified as Linear Regression, graphical and
analytical. Although the entire tests are carried out simultaneously, as complementary to
one another, they have their own highlights and short comings
Statistical Parameters Analysis
The basic statistical parameters like average annual rainfall, standard deviation, co-
efficient of variation, kurtosis co-efficient, skewness co-efficient are carried out in 97
rain gauge stations over the Cauvery basin in Karnataka to characterise rainfall
occurrence.
Graphical Method
• As the volume of data increases it becomes more and more difficult to understand the
main features by observing the numerical values
• But, graphical plotting‟s provide a bird‟s eye view of such data enable the reader to
visualise the meanings of the whole length of bulky records at a single glance.
• However the conclusions drawn from the results of graphical methods may be highly
prejudiced
53

Linear Regression
• Linear regression is one of the simplest methods to calculate the trend of data in time
series
• In this case, the null hypothesis is that the slope of the line is zero or there is no trend
in the data
• Microsoft Excel was used to calculate the trend lines and statistical values of linear
regression analysis
• The value is a fraction between 0.0 - 1.0. A R2 value of 1.0 means that the correlation
becomes strong and all points lie on a straight line.
• On the other hands, when R2 value of 0.0 means that there is no any correlation and no
linear relationship between X and Y.
Mann Kendal Trend Analysis
• Mann Kendall test is a statistical test widely used for the analysis of trend in
climatologic and in hydrologic time series
• There are two advantages of using this test. First, it is a non parametric test and does
not require the data to be normally distributed
• According to this test, the null hypothesis H0 assumes that there is no trend (the data is
independent and randomly ordered) and this is tested against the alternative hypothesis
H1, which assumes that there is a trend.
54

• Another statistic obtained on running the Mann-Kendall test is Kendall's tau, which is a
measure of correlation and therefore measures the strength of the relationship between
the two variables
• Software used for performing the statistical Mann-Kendall test is Addinsoft‟s XLSTAT
2012. The null hypothesis is tested at 95% confidence level for both, precipitation data
for the selected rain gauge stations over the Cauvery basin in Karnataka.
• In addition, to compare the results obtained from the Mann-Kendall test, linear trend
lines are plotted for each stations using Microsoft Excel 2007.
Discharge Analysis in the Basin
• The collected data were analysed using EXCEL software, yield in a year in each station
was calculated, decade wise yield is also calculated
• co-efficient of determination (denoted by R2) is a measure used in statistical analysis
That assesses how well a model explains and predicts future outcomes has carried out in
each station
• A bar graph of yield versus Time has been plotted.
55

DISTRESS SHARING of CAUVERY RIVER WATER
Anomalies in Annual Rainfall
• It is individual deviations from mean
• The departure of annual rainfall from the long term mean is used to describe the
anomolies in the annual rain fall
• In the present study, however years having anomalies greater than 1.0σ and -1.0σ are
determined for the two rain gauge stations in each sub basin in Karnataka.
• If the Normalised anomaly value is greater than 1.0 then such year is called as Excess
rainfall years (ERY)
• If the value is lesser than -1.0 then such years is treated as Dry rainfall years (DRY)
and the value is in between -1.0 & 1.0 then it is a Normal year.
56

Probability Analysis To Determine Wet And Dry Years
• Frequency analysis is carried out to find the typical wet and dry years.
• To carry out this analysis 35 years rain fall data were required.
• Log normal distribution were applied on the records so as to find the series of
annual rainfall magnitudes corresponding return periods of 5,10,20 years using the
excel spread sheet on MS office.
• Log normal distributions is a probability distribution of a random variable whose
logarithm is normally distributed.
• Out of 97 stations probability analysis is carried out for 30 stations
57

YIELD CALCULATIONS
The yield over the Cauvery basin in Karnataka was carried out in two methods one is
SCS Curve Number method in the plain areas and the regionally developed RF-RO
model in the Western Ghats areas
Regionally Applicable RF-RO Model
• The Normalized Antecedent Precipitation Index (NAPI) used in the present study was
defined as the ratio of the API for the period to the normal monsoon rainfall multiplied
by 100. Mathematically it has been defined as
NAPI= (API/NRF) *100
The investigations for development of locally applicable models for estimation of 3-
daily and 5-daily runoff in the western ghat regions of Karnataka, which were discussed
in the preceding sections, are summarized as follows.
RO=A * (RF) + B * (NAPI)
Estimation of RF and NAPI coefficients for each basin is calculated using the
expressions
58

Datasets
Coefficients
Monsoon
period
classification
Early
monsoon
Core
monsoon
Late
monsoon
Equationsfor
daily
RF
(a)
0.16 0.143 * NRF - 0.0758 0.28
NAPI
(b)
1.83 * NRF - 2.79
2.24 + 0.0004 *
AREA + 0.93 * NRF
6.17 * NRF - 11.45
3-daily
RF
(a)
0.18 0.181 * NRF - 0.05 0.38
NAPI
(b)
2.24 * NRF - 3.29
5.64 + 0.0012 *
AREA - 0.77 * NRF
4.21 * NRF - 6.07
5-daily
RF
(a)
0.20 0.076 * NRF + 0.32 0.48
NAPI
(b)
3.04 * NRF - 5.81
-1.43-0.0002 *
AREA + 1.73 * NRF
3.14 * NRF - 3.85
Final expressions for estimation of RF and NAPI coefficients
59

SCS Curve Number Method for Daily Runoff
• The CN method was originally developed by the U.S soil conservation service (SCS,
1972) for estimating runoff from storm rainfall data.
• It has been modified by the Ministry of Agriculture (CUSU, 1972) for use in India, to
compute runoff from daily rainfall data.
The first concept is that the ratio of actual amount of runoff to maximum potential
runoff is equal to the ratio of actual infiltration to the potential maximum retention.
This proportionality concept is expressed as
(P-Ia-Q) / S= Q / (P-Ia)
Where: P = precipitation in millimetres; Q = runoff in millimetres;
S = potential maximum retention in millimetres; Ia = Initial Abstraction
The second concept is that the amount of initial abstraction is some fraction of the
potential maximum retention and thus expressed as
(For Indian condition Ia = 0.05S)
Where: S = (25400/CN)-254
Q= (P-.05S)2 / (P-0.95)
60

Hydrologic Soil Group (HSG)
As per National Engineering Handbook (NEH) developed by USDA, soils are classified
in four groups A, B, C and D based upon the infiltration and other characteristics.
Group C: Soils in this group have moderately high runoff potential and low infiltration
rate, when thoroughly wet. Water transmission is somewhat restricted through the soil
Group D: Soils in this group have high runoff potential and low very low infiltration
rate, when thoroughly wet. Water transmission is restricted through the soil.
Antecedent Moisture Condition (AMC)
AMC indicates the moisture content of soil at the beginning of the rainfall event
AMC
Total Rain in Previous 5 days
Dormant Season Growing Season
I Less than 13 mm Less than 36 mm
II 13 to 28 mm 36 to 53 mm
III More than 28 mm More than 53 mm
AMC for determination of CN value
61

CN for AMC I is calculated using the following
relations:
CN (I) = (4.2 (CN))/ (10-.058(CN))
CN for AMC III is calculated as:
CN (III) = (2.3 CN) / (10+.13(CN))
Land Use Hydrologic Soil Group
A B C D
Agriculture Land 76 86 90 93
Build Up land 49 69 79 84
Tree 41 55 69 73
Forest 26 40 58 61
Wasteland 71 80 85 88
Water bodies 97 97 97 97
Curve Number for HSG under AMC II Conditions
SCS Curve Number Method is used to estimate the daily runoff over a 7 sub basin in the
plain areas of Cauvery basin in Karnataka.
62

Water Sharing during Distress Years
• The above analysis were carried out to calculate the rainfall and runoff in the normal
and as well as in the deficit years.
• The Thiessen Polygon method is used to calculate the weighted average rainfall in
normal year, five year deficit and ten year deficit by considering two rain gauge
stations in each basin.
• There will be deficiency in rainfall for five and ten year return period compare to
normal years.
• The deficiency in rainfall affects the runoff and there is decrease in yield.
• Based on the yield calculations, reasonable water sharing between Karnataka and
Tamilnadu has been worked out for rainfall deficit years of 5 years and ten years
return period.
63

STATISTICAL PARAMETERS ANALYSIS
• Basic Statistical parameters of all (97) Rain Gauge Stations were carried out and for
the selected stations the linear regression, graphical representation were carried out
in the present study
• The average annual rainfall of the rain gauge stations in Cauvery basin ranges from
584 mm (Gajnur) to 6729 mm (Talacauvery) indicating a wide variation from one
station to the another station.
• It can be seen that the maximum rainfall occurred at station Bhagmandala with 9986
mm in the year 1961. The minimum occurred at the station Nagmangala with
rainfall of 134 mm in the year 2016
• Most of the stations have kurtosis coefficient negative indicating that a distribution
is more flat than the normal distribution.
65

• Only one station Palya has a kurtosis coefficient greater than 6.58 indicating that
low rainfall values are observed more often than high rainfall values.
• It is observed that the maximum variation in the annual rainfall occurs at station
K R Pet with a coefficient of variation of 60% and minimum at the station
Sampeji with a coefficient of variation is around 17%.
• The average coefficient of variation is around 28% indicating the rainfall varies
reasonably from one year to the next
• The skewness coefficients for most of the stations are positive indicating that the
low rainfall happens frequently whereas the high value rainfall happens rarely
• For some of the stations the skewness coefficient is equal to or nearly equal to
zero indicating the data follows a normal distribution.
66

• However, the quantum of rainfall varied at any given rainfall station from year to
year.
• The observations of 97 stations in the Cauvery basin, looking at the histogram the
rainfall is neither increasing nor decreasing but there is a fluctuation.
• Only in some of the stations, for the last 5 years, a decrease in the quantum of
rainfall has been observed.
• The coefficient of determination R2 value varies from 0.01 to 0.43. In other
words, there is no significant trend in annual rainfall for Cauvery basin.
Rainfall Trend Analysis for the Cauvery Basin in Karnataka
67

Rainfall Trend Analysis using Mann-Kendall Statistics
Station Name
Range
(Years)
Kendall's
Tau
MK
Statistic(S)
P- Value Trend
Statistically
Significant
C H Nagara 37 -0.165 -110 0.923 Decrease No
Gundlupete 36 0.044 28 0.357 Increase No
Harangi 37 -0.003 -2 0.505 Decrease No
H D Kote 37 0.078 52 0.252 Increase No
Hunsur 37 -0.057 -38 0.686 Decrease No
K R Nagara 37 0.150 100 0.098 Increase No
K R Pete 37 -0.105 -70 0.05 Decrease No
Maddur 37 -0.009 -6 0.526 Decrease No
Mallavelli 35 -0.188 -125 0.948 Decrease No
Nanjangudu 37 0.009 6 0.474 Increase No
Pandavapura 37 0.054 36 0.324 Increase No
Periyapatna 37 0.024 16 0.422 Increase No
Shanthalli 37 -0.096 -64 0.795 Decrease No
Somwarpete 37 0.066 44 0.287 Increase No
Srirangapatna 37 0.033 22 0.392 Increase No
Yelandur 37 -0.090 -60 0.780 Decrease No
Mann-Kendall Statistic Result for annual rainfall Data
69

THE DISCHARGE ANALYSIS
• The discharge data of Cauvery River and its tributaries were collected from 15
hydrological observation sites.
• The available data lengths were different for different stations situated in the
Cauvery basin of Karnataka.
• For some of the hydrological sites the discharge data is available from 1971
onwards. But for few stations data is available from 2000 onwards
• The annual yield in each station was calculated based on the discharge data.
• For each hydrological observation site a plot of annual yield was made for the
period for which discharge data is available.
• The histogram of the annual yield at each station neither indicate increasing nor
indicate decreasing trend but only fluctuation in the annual yield
• The coefficient of determination, R2 value varied from .02 to .5. The R-squared
statistics indicates a very weak relationship between the variables (Yield) and
year. In other words, there is no significant trend in annual discharge data of
Cauvery basin. 71

The Decade wise Yield Computations
• The decade wise yield was computed for the 9 hydrological observations sites. For
some of the hydrological sites the discharge data is available from 1971 onwards. But
for few stations data is available from 1978 onwards
• The computed R2 values for different stations varied in the range of 0.2 to 0.96. For
most of the observation stations higher values of R2 were noticed. The Decade wise
calculations show decrease in trend in all the stations except K M wadi
73

Sl
No
Gauging
Station
Name
Decade
Q in
TMC
Sl
No
Gauging
Station
Name
Decade Q in TMC
1 M H Halli 1978-87 594 6 Kollegala 1971-80 2964
1988-97 481 1981-90 1768
1998-07 234 1990-00 2446
2001-10 2093
2 K M Wadi 1979-88 99 7 Kanakapura 1979-88 60
1989-98 137 1989-98 59
1999-08 110
3 Muttenkera 1973-82 1006 8 T K Halli 1978-87 229
1983-92 807 1988-97 245
1993-02 848 1998-07 268
2003-12 838
4 Kudige 1973-82 1043 9 Biligundlu 1971-80 3232
1983-92 849 1981-90 2226
1993-02 847 1990-00 2886
2003-12 840 2001-10 2202
5 T N Pura 1971-80 1282
1981-90 925
1990-00 1040
2001-10 939
Decade wise Yield Data for Individual Gauging Stations
74

DISTRESS SHARING OF CAUVERY RIVER WATER
Sl No Station Name Data Length in Years ERY DRY
1 Chamarajnagar 37 7 4
2 Gundlupet 36 5 6
3 Harangi 37 8 7
4 Heggadadevanakote 37 6 7
5 Hunsur 37 7 7
6 Krishnarajanagar 37 5 6
7 Krishnarajapet 26 7 8
8 Maddur(Somanhalli) 37 6 5
9 Malavally 35 5 3
10 Nagamangala 36 4 6
11 Nanjangud 37 3 6
12 Pandavapura 37 5 8
13 Periyapatna 37 4 6
14 Shanthahalli 37 6 4
15 Somwarpet 37 6 7
16 Srirangapatna 37 4 7
17 Yelandur 37 6 8
18 Sukurvar santhe 31 5 6
19 Kengeri 31 5 4
20 Yelahanka 27 4 4
Number of Anomalous Years in the Total Data Length
75

-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
2.50
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
Normalizedanolomy
Years (1980-2016)
Pandavapura
-2.50
-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
1.50
2.00
2.50
3.00
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
Normalizedanolomy
Years (1980-2016)
Harangi
76

• The results of the anomalies analysis for 20 rain gauge stations in Cauvery
catchment in Karnataka indicate that in the Western Ghats region the numbers of
rainfall excess years are more then compare to rainfall deficit years.
• In the plain areas the numbers of dry years are more compare to wet years.
• The dry years are more compared to wet years in Nanjangudu and Pandavapura
rain gauge stations.
• When compare to dry and excess rainfall years, the normal rainfall years are more
which indicates a small variation in the rainfall.
77

Return Period Analysis for the Estimation of Rainfall Magnitude
Sl
No
Station
Name
Sl
No
Station
Name
Sl
No
Station
Name
1 Kengeri 11 Chamaraja nagara 21 Kotteghera
2 Yelahanka 12 Yelandur 22 Ganibeedu
3 Maddur 13 Kollegala 23 Bankavadi
4 Nagamangala 14 M M Hills 24 Nagar Hole
5 Doddamagge 15 Belur 25 Periyapatna
6 K R Nagara 16 Sukurvar Santhe 26 Hunsur
7 Pandavapura 17 Shanthalli 27 Bhagmandala
8 Srirangapatna 18 Surlabhi 28 Khushalnagara
9 H D Kote 19 Chikmangluru 29 Srimangala
10 Gundlupete 20 Gendenhalli 30 Ponnampet
List of Rain Gauge Stations for Return Period Analysis
78

Sl
No
Station
Name
Return Period,
Years
Rainfall
in mm(X)
Year
1 Harangi 5 869 2012
10 785 2002
20 720 1988
2 Chamarajnagara 5 530 2006
10 460 2002
20 409 2002
3 H D Kote 5 673 2002
10 608 1989
20 558 1986
4 K R Nagara 5 510 1989
10 455 1985
20 414 2012
5 Maddur 5 592 2002
10 526 2011
Rainfall in Typical Dry Years with 5, 10, 20 Year Return periods
79

Weighted Average Rainfall and Yield Calculations
• The basin is distinguished as two parts, Western Ghats and plain areas
• Compared to normal rainfall, once in 5 and 10 year return period rainfall have
deficit of 23 and 33 per cent respectively
• For the calculation of the yield in the Cauvery basin, the whole basin was divided
into 15 sub-basins and two rain gauge stations for each sub basin were considered
• In the normal year, the yield in the Cauvery basin in Karnataka is 414 TMC, but in
the 5 and 10 year deficit it yields 292 TMC and 221 TMC respectively
80

Sl
No
Basin Name Catchment Area
Weighted Average
Normal Rainfall
5 Year Deficit
Rainfall
10 Year Deficit
Rainfall
in km2 in cm in cm % in cm %
PLAIN AREAS
1 ARKAVATHI 4161 87 69 -20 _ _
2 SHIMSHA 8664 81 60 -27 45 -44
3 HEMAVATHI DAM up to KRS 4900 71 42 -41 42 -41
4 KRS DAM up to T N PURA 1338 71 46 -35 46 -35
5 KABINI DAM up to T N PURA 4485 81 63 -22 56 -31
6 CHIKHOLE AND SUVERNAVATHI 998 77 55 -29 55 -29
7 REMAINING AREA 3319 73 46 -38 46 -38
WESTERN GHATS
8 YAGACHI DAM up to HEMAVATHI DAM 1763 202 171 -15 171 -15
9 YAGACHI DAM as OL 551 102 --- --- 69 -33
10 SAKLESHPURA as OL 588 240 220 -8 188 -21
11 HARANGI KUDIGI as OL 569 500 410 -17 360 -29
12 CAUVERY up to KHUSHALNAGARA 1188 320 250 -22 230 -28
13
LAKSMANTHIRTHA up to KANOOR
BRIDGE 687 220 190 -14 100 -55
14 LAKSMANTHIRTHA K M WADI as OL 700 88 67 -24 63 -29
15 KABINI DAM as OL 445 90 80 -11 60 -33
Average
Deficiency
(%) -23 -33
Weighted Average Rainfall of the individual Basin
81

Sl
No
Basin
Name
Catchment
Area
Normal
Year Yield
5 Year Deficit
Yield
10 Year Deficit
Yield
in km2 in Mm3 in Mm3 % in Mm3 %
PLAIN AREAS
1 ARKAVATHI 4161 532 370 -30 _ _
2 SHIMSHA 8664 1012 693 -32 520 -49
3 HEMAVATHI DAM up to KRS 4900 588 287 -51 287 -51
4 KRS DAM up to T N PURA 1338 170 80 -53 80 -53
5 KABINI DAM up to T N PURA 4485 527 303 -43 256 -51
6 CHIKHOLE AND SUVERNAVATHI 998 124 78 -37 78 -37
7 REMAINING AREA 3319 293 194 -34 194 -34
WESTERN GHATS
8 YAGACHI DAM up to HEMAVATHI DAM 1763 1988 1696 -15 1365 -31
9 YAGACHI DAM as OL 551 235 _ _ 115 -51
10 SAKLESHPURA as OL 588 1139 928 -19 639 -44
11 HARANGI KUDIGI as OL 569 1600 1150 -28 950 -41
12 CAUVERY up to KHUSHALNAGARA 1188 2200 1536 -30 1236 -44
13 LAKSMANTHIRTHA up to KANOOR
BRIDGE
687 1019 788 -23 426 -58
14 LAKSMANTHIRTHA K M WADI as OL 700 250 130 -48 110 -56
15 KABINI DAM as OL 445 53 35 -33 _ _
TOTAL 34356 11732 8268 6256
415 (TMC) 292 (TMC) 221
(TMC)
Average Deficiency
(%)
-34 -46
Yield in the Individual basin of Cauvery Catchment in Karnataka
82

Weighted Average Rainfall of the Individual Basins
83

Yield of the Individual Basins
84

Possibilities of Sharing the Water during Distress Years
State/Year
Normal Year
(TMC)
5 Year Deficit
(TMC)
10 Year Deficit
(TMC)
% of Deficit in Rainfall of
Cauvery Basin in Karnataka
_ - 23% - 33%
% of Deficit in Yield of
_ - 34% - 46%
Total Yield in Karnataka 415 292 221
The Water availability during Normal and Distress Years
85

• Karnataka contributes 42% of Cauvery basin area, but it gets around 37% of Cauvery water.
• Tamil Nadu contributes nearly 54% of Cauvery catchment area, but gets 57% of Cauvery water share.
• Karnataka has been given lesser share than its basin area due to historical use.
• During the normal rainfall years, there are no problems with the allocated water by the tribunal
• If the monsoon fails there is a distress and the allocated states face a huge problem due do decrease in
the available yield
• On an average, once in five years Cauvery basin in Karnataka receives 23% deficit rainfall. This will
result in reduction in water yield by 34%
• Once in ten years Cauvery basin in Karnataka receives 33% deficit rainfall. This will result in 46% less
yield of water
• As a result only 221 TMC of water will be available in Cauvery basin
• If the tribunal order of releasing 192 TMC of water is obeyed then Karnataka will be left with only 29
TMC.
• This much of water is not even sufficient to meet drinking water needs in Cauvery basin. Hence the
following alternatives can be thought of.
86

Option 1
State/Year
% of Share
to each state
Normal Year
(TMC)
5 Year Deficit
(TMC)
10 Year Deficit
(TMC)
% of Deficit in Rainfall
of Cauvery Basin in
Karnataka
_ _ (-23%) (-33%)
Cauvery Basin in
Karnataka
_ _ (-34%) (-46%)
Total Yield in
Karnataka
100 415 292 221
Karnataka‟s share 53.73 223 157 119
Tamil Nadu share from
Karnataka
46.27 192 135 102
The Proportional share of Water based on Tribunal Award during Distress years
87

Option 2
State/Year
Normal Year
(TMC)
5 Year Deficit
(TMC)
10 Year Deficit
(TMC)
% of Deficit in Rainfall of
_ (-23%) (-33%)
_ (-34%) (-46%)
Total Distress - 123 194
Share of distress for
Tamilnadu (54:42 ratio)
- 69 109
Karnataka
192 123 83
Water available for
Karnataka
223 169 138
The Proportional share of Water in Distress years based on Areas of Drainage Basin
88

Option 3
• The distress during rainfall deficit years can be shared in proportion to the command area
under cultivation.
• This is based on the concept that the water conservation steps are initiated in both the
states.
• Hence available water can be judiciously used in both states keeping in mind the larger
interest of the people in both the states. The area under irrigation in Karnataka and
Tamilnadu is shown in Table
Year Area (gross lakh acres)
in Karnataka
Area (gross lakh acres)in
Tamilnadu
1901 1.11 13.45
1928 1.11 14.44
1971 4.42 25.30
1990 21.38 25.80
Areas under Irrigation in Karnataka and Tamilnadu
From the Table it can be seen that 45% of irrigated area is in Karnataka and 55% of
irrigated area is in Tamilnadu. Hence the distress can be shared between Karnataka and
Tamilnadu in the ratio of 45:55
89

State/Year
% share of
Distress
Normal Year
(TMC)
5 Year Deficit
(TMC)
10 Year Deficit
(TMC)
% of Deficit in Rainfall
of Cauvery Basin in
Karnataka
_ _ (-23%) (-33%)
Cauvery Basin in
Karnataka
_ _ (-34%) (-46%)
Share of distress for
Tamilnadu
55 - 68 107
Karnataka
192 124 85
Available water for
Karnataka
45 223 168 136
The Proportional share of Water in Distress Years based on Command Area under
Cultivation
90

The Comparison of Different Options
State/Year
Normal Year
(TMC)
5 Year Deficit
(TMC)
10 Year Deficit
(TMC)
Option 1 192 135 102
Option 2 192 123 83
Option 3 192 124 85
The Proportional share of Water in Distress Years with different Options
91

CONCLUSIONS AND RECOMMENDATIONS
92

CONCLUSIONS
1. The average annual rainfall of the rain gauge stations in Cauvery basin ranges from
584 mm (Gajnur) to 6729 mm (Talacauvery) indicating a wide variation from one
station to the another station.
2. It is observed that the maximum variation in the annual rainfall occurs at station K
R Pet with a coefficient of variation of 60% and minimum at the station Sampanje
with a coefficient of variation of 17%.
3. Although annual rainfall variations were observed in all the raingauge stations in the
Cauvery basin of Karnataka, no definite trend in rainfall has been observed.
4. The annual discharges in the selected hydro observation sites (gauging stations) have
shown fluctuations without indicating a trend in the annual discharge.
5. But decade wise discharges in the gauging stations indicate a decreasing trend. In
other words the quantum of flow in the gauging stations is decreasing from one
decade to another decade indicating more usage of water by upper riparian regions.
6. In the normal year, the yield in the Cauvery basin in Karnataka is 415 TMC ft of
water.
93

7. The annual rains in Cauvery basin with 5 year and 10 year return periods will
have deficit of 23% and 33% respectively compared to normal year.
8. The 5 year and 10 year deficit rains in the Cauvery basin of Karnataka contribute
to reduction in the yield by 34% and 46% respectively. So for 5 and 10 year return
periods water available in Cauvery basin of Karnataka will be 292 TMC ft of
water and 221 TMC ft of water respectively.
9. All the three options more or less suggest almost same quantum of discharge to
Tamilnadu during a distress year.
10. During 5 year deficit rain in Cauvery basin of Karnataka Tamilnadu shall be
satisfied with a discharge 123 to 135 TMC ft of water from Karnataka.
11. Similarly once in ten years Cauvery basin in Karnataka faces a severe drought.
During that year Tamilnadu shall be satisfied with 83 to 102 TMC ft of water.
12. A just solution to river water sharing between Karnataka and Tamilnadu is
possible. Both states shall agree to share the distress in proportion to the quantum
of water awarded by the Tribunal.
94

RECOMMENDATION
1. The total rainfall in the Cauvery basin is highly fluctuating and deficit rainfall
occurs with short return periods. Hence it‟s recommended that the farmers in the
Cauvery basin shall adopt the water conservation techniques.
2. The growth of crops which required intensive irrigation shall be reduced in the
Cauvery basin of both Karnataka and Tamilnadu.
3. The cultivation of dry crops and semi dry crops shall be encouraged by the
government agencies which in turns help in reducing the water demand.
4. The government of Tamilnadu and Karnataka can easily evolved a distress sharing
arrangement for the Cauvery water for peace and prosperity of the region and to
eliminate protracted legal battles in the highest court of the country.
95

SCOPE for FUTURE STUDY
1. Due to the lack of available data and time, the yield analysis was carried out by
considering 2 stations for each basin. By increasing the number of stations in a basin
more accuracy can be achieved.
2. In the present study, the yield estimation was carried out yearly and the water should
be shared „proportionately‟ on the yearly basis.
3. The tribunal award has mentioned monthly wise water allocations to Tamilnadu
from Karnataka. So further analysis can be carried out to workout monthly
discharges during deficit rainfall years.
4. Develop mathematical models to estimate the water availability in the river based on
the rain estimation of the particular year. Based on the details decide the particular
crop/crops to be grown in the particular area.
96

REFERENCES
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Saudi Arabia - Rainfall analysis”, Journal of Climate research. Vol. 9, pp. 213-223.
 Adeloye A. J and Montaseri M (2002),“ Preliminary stream-flow data analyses prior to water
resources planning study”, Journal of Hydrological sciences. Vol. 47, pp 679–692.
 Bera S.( 2017), “Trend Analysis of Rainfall in Ganga Basin”, India during 1901-2000. Am J
Clim Chang. Vol 6, pp.116-131.
 Bhuvaneswari K, Geethalakshmi Vand Lakshmanan A. (2013), “Rainfall scenario in future over
cauvery basin in india”, Indian J Sci Technol Vol 6 pp.4966-4970.
 Chen, H., Guo, S., Xu, C.Y. and Singh, V.P. (2007), “Historical Temporal Trends of Hydro-
Climatic Variables and Runoff Response to Climate Variability and Their Relevance in Water
Resource Management in the Hanjiang Basin”.
 Delhi N.( 2007),” The Report of the Cauvery Water Disputes Tribunal‟, Vol IV.
 Dindang A, Taat A and Eng-Beng P.(2013), “Statistical and trend analysis of rainfall data in
Kuching, Sarawak from 1968-2010”, Malaysian Meterological Dep. pp. 6-14.
 Donald H. Burn, Juraj M Cunderlik and Alain Pietroniro (2004),”Hydrological trends and
variability in the Liard River basin” Journal of Hydrological Sciences Vol. 49, February 2004.
97

 Sebastian, P.A. (1992). “Cauvery Water Dispute and State Violence”, Economic and Political Weekly,
27(27): 1371-1372.
 Seligman and Daniel, Laws of the Rivers: The Legal Regimes of Major Interstate River Systems in
the United States (Colorado River Commission of Nevada 2006).
 Seligman Daniel (2011),” Resolving Interstate Water Conflicts a Comparison of The Way India and
The United States Address Disputes On Interstate Rivers”, Institue of water policy National
university of singapore, Serial No.IWP/WP/No.2/2011.
 Sherk and George W.( 2000), “Dividing the Waters the Resolution of Interstate Water Conflicts in the
United States “,(Kluwer Law International).
 Suppiah R and M M. Yoshino (1984), Spatial and temporal patterns of monthly precipitation
variability over the Srilanka, Journal of Meteorology and Atmospheric Physics, pp- 329-340.
 Sushant S, Balasubramani K and Kumaraswamy K. (2015), “Environmental Management of River
Basin Ecosystems”.pp 21-42.
 Sushma M S and Putty R yadupathi.(2014),”Multi –Daily Runoff Relationships A Case Study in
Western Ghats”.
 Tayeb Raziei, (2005) “Annual Rainfall Trend in Arid and Semi-arid Regions of Iran” ICID 21st
European Regional Conference 2005, 15-19 May 2005 Frankfurt.
 The Cauvery Water Disputes Tribunal with the Decision (2007), Vol II
98

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