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Water Resources in the Indus-Gangetic
Basin
http://bfp-indogangetic.iwmi.org:8080/
Bharat Sharma
Basin Focal Project for the Indus-Gangetic Basin
http://bfp-indogangetic.iwmi.org:8080/
The Indus- Gangetic Basin
• 255 M ha drainage area across 4 major and 2 minor countries.
•747 million people (2001, Census)
• Physical and economic water scarcity.
• Both covered under 10 most endangered rivers (WWF)
Indus River Basin
• 110 M ha area
•Mount Kailash in Tibet
• Indus Water Treaty
• Annual system inflow of 175 BCM (CV~ 13%)
• Snow and ice melt form a large part
Changing pattern of surface irrigation diversions in the IBIS, Pakistan
• 15 barrages•45 main canals•14 river-link canals
Water Resources in the Ganges Basin
BCM
•Gangotri glacier in Gomukh•1.09 m km2 ( 79-I, 13-N, 4-C, 4-B)• Tehri Dam, Farakka Barrage
300000
400000
500000
600000
700000
800000
900000
1000000
1951 1955 1959 1963 1967 1971 1975 1979 1983 1987 1991 1995 1999
An
nu
al r
un
off
(m
cm)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
An
nu
al p
reci
pit
atio
n (
m)
Runoff
Precipitation
Whole basin annual precipitation and runoff from 1951 to 2000 in the Ganga Basin
• Ganges basin has high annual average rainfall of more than 1000 mm, averaged across the basin, and 2000 mm or more in Himalayan catchments.
•Net discharge from the Basin accounts for more water than any other use, followed by rainfed agriculture.
• The impact of increasing irrigation efficiency ( from 40 to 60%) has relatively little impact on water availability overall. However, increase in irrigated area may lead to overall net increase in water consumption and a marginal impact downstream.
Ganges Basin Water Use
McKirby et al, 2009
The spatial distribution of major water uses in catchments of the Indus and Ganges Basin
Indus Basin Ganges basin
McK
irby e
t al, 2
00
9
0
50000
100000
150000
200000
250000
300000
350000
rainfedagriculture
grassland woodland +other
irrigatedagriculture
net runoff
Annual
wat
er u
se (m
cm)
Summary of major water uses in the Indus and the Ganges Basin
0
100000
200000
300000
400000
500000
rainfed agriculture grassland woodland + other irrigated agriculture net runoff
An
nu
al w
ater
use
(m
cm)
Indus Basin
Ganges Basin McK
irby e
t al, 2
00
9
Groundwater Recharge in Indus- Gangetic Basin
Basin Name Groundwater Available
(BCM)
Annual Groundwater Draft (BCM)
Stage of GW Development
(%)Irrigation Domestic, Industrial & others
Total
Ganga BasinIndia 168.7 94.4 8.2 102.4 61Nepal 11.5 0.8 0.3 1.1 10
Bangladesh 64.6 25.2 4.1 29.3 45
Total 244.8 120.4 12.6 132.8 54
Indus BasinIndia 30.2 36.4 1.6 38.0 126
Pakistan* 55.1 46.2 5.1 51.3 93Total 85.3 82.6 6.7 89.3 105
Groundwater availability and its use in the Indus-Gangetic Basin
IG Basin states Area under tubewell irrigation (000 ha)
Net irrigated area (000 ha)
Share of groundwater in increased total irrigated area
1995 2005% increase 1995 2005
Indian_IGB states
15.5 20.9 35 35.5 40.5 110Pakistan* 2.6 3.0 18 15.8 16.7 57Bangladesh 2.3 3.7 59 3.5 5.0 93Nepala 0.1 0.2 115 0.9 1.2 40Total 22.5 30.0 33 55.8 63.4 99
Decadal increase in tubewell irrigated area in Indus-Gangetic Basin countries
Groundwater quality in IG basin
Rechna-Doab, PakistanIG Basin states, India
Predicted arsenic contamination in ground waters of Ganga basin
Ganga River Basin Annual water balance components
0
200
400
600
800
1000
1200
1400
1600
1800
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
Year
Va
lue
(m
m)
PrecipitationETWater Yield
Control Scenario
0
200
400
600
800
1000
1200
1400
1600
1800
20
41
20
42
20
43
20
44
20
45
20
46
20
47
20
48
20
49
20
50
20
51
20
52
20
53
20
54
20
55
20
56
20
57
20
58
20
59
20
60
Year
Va
lue
(m
m)
PrecipitationETWater Yield
GHG Scenario
Source: Gosain, AK, IIT_D
Ganga River – Annual Peak
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
1 3 5 7 9 11 13 15 17 19
Year Number
An
nu
al d
aily
pea
k d
isch
arg
e (c
um
ecs)
Control ScenarioSubbasin 11
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
1 3 5 7 9 11 13 15 17 19
Year Number
An
nu
al d
aily
pea
k d
isch
arg
e (c
um
ecs)
GHG ScenarioSubbasin 11
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
1 3 5 7 9 11 13 15 17 19
Year Number
An
nu
al d
aily
pea
k d
isch
arg
e (c
um
ecs)
Control ScenarioSubbasin 23
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
1 3 5 7 9 11 13 15 17 19
Year Number
An
nu
al d
aily
pea
k d
isch
arg
e (c
um
ecs)
GHG ScenarioSubbasin 23
Sou
rce: G
osain, A
K, IIT
_D
Events exceeding arbitrary thresholds in Ganga River Basin
Discharge (cumecs)
Control GHG Control GHG
Ganga Subbasins
Sub11 Sub11 Sub23 Sub23
Discharge>10000
>20000
6 7
1 5
Discharge>12000
>30000
1 6
0 2
Source: Gosain, AK, IIT_D
• In terms of infrastructure for water storage and irrigation, Indus basin is well developed . However, lack of proper maintenance and management of reservoirs and canal systems is seriously impacting the dry season cultivation.
• Most of the available water in the Indus basin is already committed leaving only bare minimum for the environmental flows.
•Indus basin is also one of the biggest groundwater usage regions and hot spot in the world. With such a high stress on water resources, the basin needs to employ demand management options to foster sustainable use.
•Decrease in groundwater recharge and drop in extent of snow cover induced by climate change can have serious impacts on base flow.
The Indus System
The Ganges System
•Ganges basin, in contrast, exhibits poor development and inefficient utilization of its resources.
•Need for investments in bulk water storage to take advantage of the resources and alleviate flood damages.
• River/ groundwater pollution and heavy dependence of urban centers and industry on the surface water supplies is a major cause of concern for future expansion.
•Rich endowment of groundwater resources in the basin largely remains under-utilised.
•Extreme climate events with large flood volumes and lack of storage structures may further worsen the flood regimes
