This document discusses groundwater irrigation in South Asia. It describes the massive growth of private groundwater irrigation in the region, driven by reliable energy supply. While this has provided drought resilience and economic benefits, uncontrolled use risks resource depletion and sustainability issues. The document outlines different hydrogeological settings and appropriate management approaches, emphasizing the need for community involvement, policy reforms, and integrated surface and groundwater planning.
Sustainable Groundwater Irrigation - the GW.MATE vision on resource use and management approaches, by Stephen Foster
1. GLOBAL WATER
Global Water
PARTNERSHIP
Partnership
SUSTAINABLE GROUNDWATER IRRIGATION
the GW.MATE vision on resource use
and management approaches
Stephen Foster
World Bank GW.MATE Director 2000-10
Global Water Partnership–Senior Adviser
IAH Past President 2004-08
University of London–Visiting Professor
3. SOUTH ASIA GROUNDWATER IRRIGATION BOOM
scale, drivers, benefits and issues
• massive growth of irrigation waterwells (57% total use)
mainly private investment stimulated by government
• groundwater very ‘popular’ with farmers
if energy-supply reliable almost regardless of energy cost –
direct access, near point-of-use (well-suited to pressurised irrigation)
• large groundwater economies with major social benefits
NOTABLY drought water-supply security avoiding crop yields impacts
• but unconstrained use tends to generate excessive
resource demand, with sustainability and social concerns
given population pressure on the land above most aquifers –
initially groundwater minor component of overall agro-input costs
• resource base not generally in imminent ‘danger of
collapse’ – rather more in need of some ‘loving care’
4. GROUNDWATER RESOURCE DEPLETION
some might ask why intervene –
just let anarchy and nature run its course
factors causing social and environmental cost
pumping lifts/costs increase
REVERSIBLE
borehole yield reduction
INTERFERENCE
springflow/baseflow reduction
phreatophytic vegetation stress
aquifer compaction
transmissivity reduction
saline water intrusion
IRREVERSIBLE
DETERIORATION ingress of polluted water
land subsidence and related impacts
5. help – it should have been cricket
GROUNDWATER RESOURCE MANAGEMENT
like playing soccer – need to vary strategy with
the pitch you’re playing on
hydrogeological setting of aquifer both
frames the resource problem and
constrains the management solution
6. SOUTH ASIA
simplified hydrogeological provinces
HYDROGEOLOGICAL PROVINCES
•Hard-Rock Peninsular India
• Indo-Gangetic Alluvial Plains
• Localised Graben-Fill Aquifers
• Localised Coastal Formations
• Himalayan Valley Aquifers
7. INDO-GANGETIC PLAIN
characterisation of major alluvial aquifers
• large storage (60,000 mm in upper layers)
• but insidious salinisation threats widely exist
• groundwater/surface water relations critical
8. INDIAN PUNJAB Peneplain
• ‘national grain basket’ with almost entire land area cropped for
rabi wheat/kharib rice – some 70% with waterwell irrigation
• resultant excessive groundwater abstraction equivalent to
120-150 mm/a – water-table continuously declining at 0.5-0.8 m/a
• but about 35-40% of recharge by irrigation canal seepage
• salinisation down-gradient and severe depletion around all towns
• since 2008 statutory deferral of paddy planting to June (by up to
35 days) estimated to have reduced by NBET by 80-100 mm/a ?
9. INDO-GANGETIC PLAIN
characterisation of major alluvial aquifers
• large storage (> 60,000 mm in upper layers)
• but insidious salinisation threats widely exist
• groundwater/surface water relations critical
10. GROUNDWATER MANAGEMENT APPROACHES
from Spontaneous to Planned Conjunctive Use
• integrated modelling suggests average cropping intensity could be
increased from < 150% to >220% with ‘planned conjunctive use’
(with crop diversification also increasing ‘irrigation-water productivity’)
– reducing ‘upstream’ canal losses/over-irrigation, improving
canal distribution and downstream’ irrigation service levels
– increasing groundwater use in ‘upstream areas’ and reducing use
in ‘downstream areas’ with improved canal-water availability
• but how to overcome social/economic obstacles
(power of head-canal land owners, split institutional responsibility,
comparative water cost to users and initial capital investment needs) ?
Jaunpur
Irrigation-Canal
Command
Uttar Pradesh, India
11. PENINSULAR INDIA
characterisation of weathered hard-rock aquifers
• useful but small
storage (< 500 mm)
• local sluggish flow
• recharge constraints
12. GROUNDWATER MANAGEMENT APPROACHES
Community-Based Self Regulation
• community ‘self-regulation’ goes further than
stakeholder participation in resource management
– only feasible approach for large groups of very small
users and where groundwater flow system localised
(still important for local government to play permanent ‘lighthouse
function’ in support and for up-scaling of positive outcomes)
• shift social behaviour from
‘destructive competition for
dwindling storage reserves’
(with few ‘winners’) to
‘constructive dialogue on
productive use of available
average recharge’
(with many beneficiaries)
13. MAHARASHTRA-INDIA Hivre Bazaar
successful communuity self-regulation
• successful recharge enhancement in favourable hill-foot setting
• inspired community decision on ‘dugwell only use’ for irrigation
– eliminating divisive competition for limited groundwater storage
and focusing farmers’ attention on ‘irrigation water productivity’
• crop-water budgeting based on antecedent conditions, ban on
sugar-cane cultivation and intelligent crop diversification
• excellent outcomes on groundwater sustainability, higher-value
crops/products, family incomes and eliminated water-supply tankers
15. GROUNDWATER RESOURCE MANAGEMENT
fantasy of ‘simple panacea’ or ‘quick fix’
for excessive irrigation abstraction
• first reaction of governments often is to
propose major stand-alone investments in :
• aquifer recharge enhancement and/or
• ‘efficient’ irrigation technology rather than :
• focusing on ‘underlying core issue’ of reducing
consumptive water-use (preferably ‘non-beneficial’)
with parallel need to raise water-use productivity
and to maintain/improve farmer incomes
• confronting the harsh reality of weakly-recharged
aquifers sometimes trying to support inappropriate
agricultural economies
16. GROUNDWATER MANAGEMENT APPROACHES
National/State Macro-Policy Modifications
• modifications to agricultural policy can exert a
powerful influence on groundwater irrigation use :
• discouraging alfalfa irrigation for arid-zone livestock farming
• geographic bans on sugar-cane cultivation
• statutory deferral of rice planting date
• unravelling nexus between groundwater use and
rural electricity pricing is not straight
• not I believe the primary cause of groundwater depletion
• may even be a socio-political justification for some subsidy
given invariably much lower cost to users of ‘canal-water
• however, flat-rate tariffs (by pump rating or connection
potential) are always perverse and potentially disastrous from
standpoint of energy consumption and the electricity utilities
• water-table recovery through groundwater management
measures will reap large benefits (reduce pump head losses)
17. GROUNDWATER MANAGEMENT
- contribution to key workshop outputs
• no ‘simple blueprint’ – management measures must be
tailored to ‘hydrogeological setting’ of resource
• policy and strategy development requires understanding of
both ‘use dynamics’ as well as ‘resource characteristics’
• management without user participation impossible - but by users
alone (without groundwater agency support) is questionable
FOR OPERATIONAL STAFF OR ALL AGENCIES
• groundwater agencies tend to be ‘marginalised’ and/or undersized
(rarely facing strategic issues or involved with integrated policy
development) – promote dialogue on their key functions and
transformation opportunities (identify training needs)
• inter-sector working groups/joint work programmes/co-immersion
courses between agricultural sector and groundwater sub-sector