Growing Role of Groundwater in Indian Irrigation in Transition: Needed: Transition from Surface to Aquifer Storage? Tushaar Shah International Water Management Institute [email protected]www.iwmi.org Acwadam Groundwater Conference May 21-22, 2009, Pune
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Growing role of Groundwater in Indian irrigation in transition
Groundwater provides 65% of India's water needs. Dr Tushaar Shah is one of India's foremost researchers on groundwater. This is a presentation at a groundwater conference in Pune organized by ACWADAM and supported by Arghyam.
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Growing Role of Groundwater in Indian Irrigation in Transition:
Needed: Transition from Surface to Aquifer Storage?
Tushaar ShahInternational Water Management Institute
% contribution of SWI to Agricultural GDP % contribution of GWI to Agricultural GDP
1970-73
1990-93
Until 1970, canals dominated irrigated agriculture; since then, tube wells have emerged as engines of agricultural growth.
Source: Döll, P., Lehner, B., Kaspar, F. (2002): Global modeling of groundwater recharge. In Schmitz, G.H. (ed.): Proceedings of Third International Conference on Water Resources and the Environment Research, Technical University of Dresden, Germany, ISBN 3-934253-17-2, Vol. I, 27-31
Long-term average groundwater recharge
GW use moves inversely With resource endowments
The only region where humid areas depend heavily on
groundwater.India is the only country where hardrock aquifers are exploited on such a
large scale
India’s groundwater story Unique, as are its drivers.We need to invent our own
Solutions.
Growth in Population Density around he world (people/km2) , 1700 – 1990
Expanding Cropland 1700-1990Fraction of grid cell in croplands
Drivers of Atomistic Irrigation:Ghettoization of India’s Agriculture
Shrinking of operated farm holdings in India (Source: NSS reports)
2.63
2.2
1.671.34
1.06
0
0.5
1
1.5
2
2.5
3
1960-61(17th)
1970-71(26th)
1981-82(37th)
1991-92(48th)
2002-03(59th)
ha
Small-holders add most to groundwater irrigation (Source: Agri. Census
050
100150200250300350400450
Marginal (<1ha)
Small (1-2 ha) Medium (2-10ha)
Large (>10ha)=
Farm holdings%
gro
wth
in g
roun
dwat
er
irrig
ated
are
as: 1
970-
71=1
00
1970-711976-771980-811985-861990-911995-96
The compelling advantage of pump irrigation is that it enables water-scavenging at will. Instead of adapting agriculture toIrrigation system, it adapts irrigation to farming system.
India’s groundwater boom is in some respects a response to
Disguized unemployment in agriculture.
Figure Changing structure of Indian agricultural production
65 66 62 5746
21 21 2121
28
11 10 1316 19
4 3 4 6 7
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1961-62 1971-72 1981-82 1991-92 2000-01
% o
f val
ue o
f agr
icul
tura
l out
put
Field crops, sugar, fibres High value crops Milk Other livestock
Canal and tank irrigated areas condemned to low-value crops unresponsive to precision irrigation.
Much diversification isOccurring outside Command areas (IFPRI).
Much diversification Requires small dozes ofYear-round, on-demandIrrigation.
Value added farming Will expand withWaste-water irrigation andGroundwater.
Our irrigation planning is preoccupied with food grains; Indian farmer is diversifying in a hurry.
Classes of Irrigators in India
Gross revenue &Irrigation cost/ha
20-22 mha
Million ha of irrigated area
cana
ls &
tank
s
30-32 mha
Own
ele
ctri
c pu
mps
10-12 mha
Elec
tric
pum
p pu
rcha
se12-15mha
Own
die
sel p
ump
7-8mha
Rent
ed d
iese
l pum
p
Own and rented gen-sets
15-18 million Marginal farmers
and share cropper families
Consequences of Groundwater Boom
•Groundwater depletion and decline in drought resilience•Quality degradation and public health hazard•High energy costs and unsustainable farming
•4% of India’s GHG by pumping•Challenge of adapting to Climate Change
The problem is: We neither manageThe supply side norThe demand side.
India has built some 270 billion m3 of surface storage which is proving a dead-weight. It irrigates only 15-16 m ha while the
same amount of groundwater irrigates 4 times more.
No matter how much we invest in surface storage, India’s dependence on aquifer storage will continue to increase.
RWH, Groundwater Recharge and Conjunctive management of rain, surface and groundwater should be the
new mantra of water management.
Recharge projects should be done withpeople’s participation but with strong science input.
Retrofitting canal systems as piped systems delivering pressurized irrigation or recharge needs to be considered.
Rethinking StorageIndia’s Water Challenge
Figure Response of Monsoonal Recovery in Water Level to Pre-monsoon Depth to Water Level
272 Sample Villages: IWMI Survey of India, Pakistan, Nepal and Bangladesh
feet
Pre-monsoon Water Level (feet) Monsoonal Rise in WL (ft)
• What factors influence monsoonal recovery in groundwater levels most?
• Pre-monsoon depth to the water level, regardless of rainfall pattern and hydro-geology. • This was strongly supported by our survey data.• It was also strongly supported by 1995 Minor Irrigation Census data.• Implication?• to a certain extent groundwater availability increases with resource development.
Figure 4: Aquifer Recovery and Pre-monsoon Water Level in 145 Districts of India: Minor Irrigation Census 1993-94
0200400600800
10001200
1 21 41 61 81 101 121 141145 district in ascending order of Pre-monsoon water table
Fee
t
Pre-monsoon Water Table Monsoonal Rise in Water Table (ft)
National Groundwater Recharge Master Plandeveloped by the CGWB aims to recharge 36
BCM by investing Rs 25000 crore..BUT
possible and needed
Badly needed but difficult without reallocation of water resources
High
possible but not needed
Neither needed nor easy
LowPressure on groundwater
resources
HighLow
Uncommitted surplus water available for recharge
Distributed RWH and groundwater recharge can be a big
part of the solution in these areas. Saurashtra and Kachchh
are leading Gujarat’s agricultural revolution.
Average Annual Growth Rates of Gross State Domestic Product (GSDP) and Gross State Domestic Product from Agriculture
(GSDPA): Major States and All India (%): 2000/01 to 2007/08(Gulati, Shah and Sreedhar 2009)
Never known for vibrant agriculture, Gujarat’s
agricultural GDP has grown @ record 9.5%/year during 2002-2007. Distributed recharge is an important
contributor.
Value formation on rainfed farm:Normal Monsoon
0100200300400
June
July
Aug
Sept
Oct
Nov
Dec Ja
nFe
bM
arAp
r
mm
rai
nfal
l
0
1000
2000
3000
Rs/
acre
Precipitation Expected cumulative value formation/acre
Economics of Rainfed Farming in Saurashtra
Value formation on rainfed farm: Early monsoon withdrawal
0
50
100
150
200
250
June
July
Aug
Sept
Oct
Nov
Dec Jan
Feb
Mar
Apr
mm
0
200
400
600
800
1000
Rs/a
cre
Precipitation Expected cumulative value formation/acre
Economics of Rainfed Farming in Saurashtra:With Distributed Groundwater Recharge
Rainfed Farming with Distributed Recharge: Normal Monsoon
0
50
100
150
200
250
300
350
June
July
Aug
Sept
Oct
Nov
Dec Jan
Feb
Mar
Apr
May
mm
rain
fall
0
1000
2000
3000
4000
5000
6000
7000
8000
Rs/a
cre
Precipitation Expected cumulative value formation/acre
Rainfed Farming with Distributed Recharge: Early Withdrawal of Monsoon
0
50
100
150
200
250
June
July
Aug
Sep
tO
ctN
ovD
ec Jan
Feb
Mar
Apr
May
mm
0500100015002000250030003500400045005000
Rs/
acre
Precipitation Expected cumulative value formation/acre
Western and Southern India have 11 million Dugwells. Many are out of use but are
Excellent recharge structures.
100 over-exploitedHardrock districts already
Have 7-7.5 million open wellsThat can be readily
used.
Rethinking StorageIndia’s Water Challenge
There is also dire need For big-ticket
Solutions to groundwaterDemand management
That can act quickly. Gujarat’sJyotigram scheme is an
Example.
Figure 1 a Electricity Network Before Figure 1 b Electricity Network after
Rural Gujarat Rewired under Jyotirgram Yojana
• Before
• Tubewells get 12-13 hours of 3-phase power supply of variable voltage, with frequent tripping, at unknown times mostly during nights
• Flat tariff: Rs 350-500/hp/year
• Massive use of capacitors to convert 1 and 2 phase power to run tubewells
• Non-farm users de-electrified because of capacitors
• Motor burn-out and rewinding the most important part of maintenance cost
• New connections not available.
• After
• Farmers get 8 hours/day of high voltage uninterrupted power at fixed schedules; night in one week, day-time the next
• Flat tariff Rs 850/hp/year
• Capacitors out; impossible
• Non-farm users get 24-hour non-stop single phase power
• Motor burn out at the minimum
• New connections allowed at high costs; now rationed;
Rural power supply environment :before and after JGS