With water resource variability rapidly growing and demands on water resources increasing, using digital tools and innovative, inclusive institutional approaches to address both challenges is becoming ever-more urgent. A recent workshop under the CGIAR Research Program on Water, Land and Ecosystems (Research Area on Variability, Risks and Competing Uses), showcased research outputs in two activity clusters - Managing Resource Variability and Risks for Resilience and Managing Competing Uses and Trade-offs - that can help increase water security for poor rural users while also improving food security and rural livelihoods.

1. The „What“ and „How“ of Managing
Groundwater Depletion
Claudia Ringler, Ruth Meinzen-Dick,
Nicos Perez and Hua Xie
Environment and Production Technology Division
International Food Policy Research Institute
December 3, 2020

2. Why groundwater matters
▪ Groundwater is characterized by low visibility, high
subtractability, low excludability and there is often a
lack of local understanding of resource dynamics
▪ GW plays a large and growing role in total water
withdrawals and use, and is the source of 20-30% of
irrigation withdrawals and a larger share of
consumptive use→ cheaper well-drilling technology
and cheaper individual pumps that became available
during the late 1970s and 1980s
▪ “Traditional knowledge” is insufficient in dealing
with rapidly developing pumping technology
▪ It has an important buffer function during climate
extreme events—storing flood water, which can be
pumped during the dry season
Image: Lyla Mehta

3. 0
50,000
100,000
150,000
200,000
250,000
300,000
1960
1962
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
Mm3//year
Can we halt groundwater depletion?
Source: Wada et al. (2012)
?

4. Time
Short Long
S
p
a
c
e
Plot
Com-
munity
Nation
Property Rights
C
o
o
r
d
i
n
a
t
i
o
n
StateCollectiveAction
Transboundary
River Basins
Reservoirs
Watershed
management
Check
dams
Terracing
Bucket
Canal
Irrigation
Well
Drip
irrigation
Furrows
Wetlands Motorized
pumps
M
a
r
k
e
t
Center
pivot
Aquifer
management
Identifying the need for institutions
Small
reservoir

5. IMPACT Food Model
IGHM (IMPACT Global Hydrology
Model)
Core Food Model
• Multi-market partial equilibrium
agricultural sector model
• Designed to simulate national and
international agricultural markets
Precipitation
Surface runoff
Baseflow Aquifers
Recharge
AggregatetoFPUs
IWSM (Impact Water Simulation
Model)
• Developed to model sectoral water
allocation
• Water consumption is constrained
by withdrawal capacity and water
availability
• A physical global hydrological
model on 0.5-degree latitude-
longitude grid
Source: IFPRI IMPACT

6. Groundwater conservation—Can it be done?
▪ Improved measurement and
monitoring
▪ Legislation and regulation—
example California
(Sustainable Groundwater
Management Act)
▪ Grow solar rather than food
crops
▪ Social learning interventions to
stimulate groundwater
governance
▪ MAR
▪ Remove perverse incentives

7. Groundwater game
▪
Games
▪ Groups of 5 men or women
▪ Choose crop A or B with different water
use & returns
▪ See effect on water table
▪ Multiple years, with and without
communication
Community debriefing
▪ How this relates to own experiences and
challenges farming
▪ Lessons and insights the participants
gained from the experience
▪ Possible solutions

8. Outcomes of Games
Game States Year #
habitations
Outcomes
Groundwater
pilot
Andhra Pradesh 2013,
2014
17 Some effect on attitudes
Communities more likely to adopt water registers
& rules for groundwater *
Surface water Rajasthan
Madhya
Pradesh
2016
2017
30
60
Communities more likely brought swelling water
conflicts to the table and engaged in dam
maintenance activities *
Groundwater
expansion
Rajasthan,
Madhya
Pradesh,
Andhra Pradesh
2014-
2019
214 Total 3747 farmers adopted less water
consumptive crops or varieties and irrigation
scheduling to save water**
*Compared to randomly selected control communities where game has no been played
**Compared to farmers’ reported behavior, prior to the games

9. Groundwater conservation—what does it take?
Explorative scenario development
➢Reference scenario: continued growth in groundwater use and depletion
➢Conservation without compensation (depletion = recharge – EF)
➢Conservation with increased GW use areas without overdraft
➢Conservation with increased investment in agricultural R&D (short duration/dwarf
varieties, drought and heat stress tolerance, etc.
➢Conservation with more effective use of precipitation – Share of effective rainfall
used increased by 5% on rainfed lands through zero till, mulching, rainwater harv
➢Conservation with declining demand for animal-sourced food in HICs +China +
Brazil (income elasticities -10%)

10. Groundwater conservation—what does it take? (HGEM)
India China USA

11. Impacts on food prices: HGEM +GW Conservation (GWC)
Source: IFPRI IMPACT

12. Impacts on food prices: HGEM GWC with selected,
increased exploitation in areas without overdraft
Source: IFPRI IMPACT

13. Source: IFPRI IMPACT
Impacts on food prices: HGEM GWC with increased
investment in wheat, rice and maize R&D

14. Impacts on food prices: HGEM GWC with increased ER
use in rainfed areas
Source: IFPRI IMPACT

15. Impacts on food prices: HGEM GWC with reduced
demand for ASF in HICs & Brazil & China
Source: IFPRI IMPACT

16. Conclusions
▪ Groundwater use in irrigation will continue to grow,
particularly with cheaper solar pumps becoming more
widely available
▪ Increased groundwater irrigation will accelerate
groundwater depletion
▪ Arresting groundwater depletion would put upward
pressure on cereal prices, particularly rice, and prices
of fruits and vegetables
▪ Several options can mitigate price impacts, such as
improving water management in rainfed areas,
investing in agricultural R&D, or reducing meat
consumption
▪ Effective measures on dealing with depletion are
starting to be developed and require effective
institutions, but GW depletion will likely continue to
grow in much of the world