EFFECTS OF IRRIGATION

WITHDRAWAL AND CLIMATE

CHANGE ON GROUNDWATER

DYNAMICS IN A SEMI-ARID INDIAN

WATERSHED

Rajendra Sishodia

Sanjay Shukla, UF

Suhas Wani, ICRISAT

Jim Jones, UF

Wendy Graham, UF

GROUNDWATER USE IN INDIA

Groundwater

accounts for 70% of

water used for

irrigation (Siebert et al.,

2010)

50% of total crop

production comes

through groundwater

irrigation

Groundwater use

increasing since 1960

Highest user of

groundwater in the

world - 240 bcm/year (Shah, 2009)

(Shah, 2009)

Figure 1 Groundwater use in different

countries

FACTORS AFFECTING INCREASED GROUNDWATER USE

Seasonal/unreliable surface water resources

Resilient buffer against natural climatic

variability - On demand availability

Fast installation and low installation cost

Free/subsidized electricity

GROUNDWATER DEPLETION IN INDIA

India is largest user of non-

renewable groundwater (Wada et al.,

2012)

29% of total groundwater

management units in semi-

critical, critical or over-

exploited category (CGWB, 2006)

GRACE satellite study - 1 feet

water table drop/yr in semi-arid

NW states (Rodell et al., 2009)

Irrigation withdrawals are

causing the depletion – Would

in turn affect the agriculture

production due to decreased

groundwater availability

Limited supply in semi-arid

regions

Source: CGWB, 2006

HISTORICAL CLIMATE CHANGE

Climate change may increase the

future GW use and decrease the

recharge

Atmospheric temperatures have

increased by 1˚ C during last century (Dash et al., 2007)

Rainfall patterns are changing in

both monsoon and other seasons

Number of extreme rainfall events

are increasing and moderate rainfall

events are decreasing in the monsoon

season (Goswami et al., 2006)

Monthly rainfall distribution is also

changing (Guhathakurta and Rajeevan,

2008)

From

http://www.mapsofindia

.com/maps/india

From

http://www.mapsofindia.com/maps/india

CLIMATE CHANGE PROJECTIONS FOR INDIA

Decrease in number of rainy days along with

increase in intense rainfall events (GOI, 2004)

More variable monsoon onset/arrival and

decrease in winter rainfall leading to droughts

during dry and hot summer (Lal et al., 2001)

Temporal shifts in rainfall may change the

groundwater recharge and availability during

different times in the year

Climate change may further increase the

groundwater demand and reduce the supply by

decreasing recharge – Increased frequency of

high intensity rainfall may increase the runoff

and reduce the recharge

GROUNDWATER MANAGEMENT STUDIES

Limited studies to quantify the effects of current

and future groundwater withdrawals and climate

change and to develop and evaluate different crop

and water management scenarios

Most of the groundwater studies related to

saltwater intrusion

Most groundwater studies conducted in tropical

and sub-tropical humid regions of India –

groundwater availability is usually higher in

tropical and sub-tropical regions due to high

rainfall and recharge Rejani et al. (2008,2009) – Orissa state – Sub-tropical wet

Thampi and Raneesh (2011) – Kerala state- Humid tropical

HYDROLOGIC MODELS

Modeling can be used to determine the effects of current and future groundwater withdrawals and climate change and also to develop suitable crop and water management scenarios

MIKE SHE (DHI, 2007), SWAT (Neitsch et al., 2009), VIC (Liang et al.,

1994) and MODFLOW (Harbaugh et al., 2000)

MIKE SHE and SWAT are the most widely used models – climate change, land management, surface water and groundwater management

MIKE SHE is a distributed, physically based hydrologic model which can be used to model overland and groundwater flow along with other main hydrologic cycle components

DHI

MIKE SHE AND SWAT

MIKE SHE - Used extensively to simulate surface and groundwater flows for variety of purposes

Climate change - Sultana and Coulibaly (2011)

Groundwater management- Demetriou and Punthakey (1999)

Irrigation Management - Singh et al. (1998)

SWAT is a conceptual, continuous time, semi-distributed model developed by USDA to predict the impact of land management on runoff and water quality in large agricultural dominated basins

Climate change - Ficklin et al. (2009)

Watershed management - Garg et al. (2011)

MIKE SHE VERSUS SWAT

MIKE SHE SWAT

Distributed finite difference cell

based model

Lumped HRU based model

Can simulate cell based spatial and

temporal soil moisture and water

table fluctuations in multi aquifer

system (water availability and soil moisture

in individual well fields or famers fields)

Only simulates temporal changes in

each (shallow and deep) aquifer

storage at sub-basin scale and soil

moisture at HRU scale

Simulates groundwater withdrawals

from multi-aquifer system

Groundwater withdrawals from

either shallow or the deep aquifer

Simulates water table fluctuation

into and below the soil layer – Better

simulation of ET from groundwater

Assumes aquifer is always below the

soil zone- Simplified ET calculation

from groundwater

ET from groundwater is accounted

in soil moisture balance

ET from groundwater is not

accounted in soil moisture balance

Spatio-temporal simulation of

moisture and water table helps in

designing management scenarios

Does not simulates the water table

OBJECTIVES

1. Use MIKE SHE in conjunction with measured soil-weather-crop-hydrologic data to quantify net groundwater recharge under current and future groundwater withdrawals for an agricultural watershed in semi-arid region of India.

2. Simulate the effects of future climate scenarios, developed from two GCMs, on groundwater levels and surface flows

3. Develop and evaluate appropriate crop and water management scenarios to maintain or enhance the groundwater recharge under current and future irrigation withdrawals and climate change

STUDY SITE

From K. Garg, ICRISAT

http://www.mapsofindia.com/

maps/india/geological.htm

WATERSHED

CHARACTERISTICS

Semi-arid

Rainfall = 850 mm

85% during monsoon (June-October)

Soil

Vertisols (black soils)

Depth 10-200 cm

Topography

Average slope <2%

Crops

Dominent - cotton (July-December)

Others - vegetables, sorghum, pigeon pea, chickpea and paddy

WATERSHED GEOLOGY

Groundwater

Hard rock aquifer

Sole source of irrigation

Deep and shallow wells

Lithology data for

Shankarpalli and surrounding

Mandals were collected from

State Groundwater Board

Lithology data, visual analysis

of open well profiles and

discussion with farmers,

NGRI, and GW board

geologists suggested that

Kothapalli lies in the

transition zone of Deccan

Traps and Granitic terrain

Surficial Aquifer (Weathered Basalt) - 10-13 m

Confining Layer (Hard/Massive Basalt) – 10-12 m

Deeper Aquifer (Fractured Granite) – 50-60 m

Surface soil

(0-2 m)

WATERSHED DATA

Weather

Kothapalli weather station (1999-continued) Rainfall, temperature, humidity, wind and solar radiation

ICRISAT weather data

Crops and land use

LAI and root distribution (literature)

Land use – Farmers survey (1999-2012)

Soil and geology

Moisture retention curves from soil samples

Well log data from CGWB and state GW agencies

Topography and stream network

Total station survey by ICRISAT

Existing stream network information and field measurements

HYDROLOGY DATA ICRISAT data on

streamflow and monthly shallow well levels from 1999

Soil moisture data (weekly) Capacitance probe

Multiple depths

Irrigation withdrawals Pressure transducers

Flow meter

Deep and shallow groundwater levels data Pressure transducers

Every 30 minutes

Daily manual deep and shallow groundwater levels since July 2011 Underway

PUMP FLOW RATES Type of well Flow Rate

(m3/hr)

Tube well 16

Tube well 8

Tube well 9

Tube well 11

Tube well 10

Tube well 7

Tube well 9

Tube well 19

Tube well 9

Tube well 12

Tube well 13

Tube well 6

Tube well 17

Tube well 13

Tube well 27

Open well 23

Open well 29

Open well 36

Open well 23

Open well 27

Open well 27

601

599

596

606

608

607613

604610

612609

610

613.5

598.5

601.5

598.5

601.5

596.5

605.5

611.5

601.25602.75

598.75

597.25

602.75

612.25

606.25605.25

605.25

605.25

612.25609.25

612.75

605

605 603603

605602

601

600

610

611608

609

609

608613

616

615615

615.5

606.5

602.5

602.5

613.5

614.5

604.5

605.75

605.25

606.75

600.25

608.75

611.25

616.75

617.75

604.75

609.25613.25

615.25

616.25

618.75

Open wells water

levels in May 2011

Open wells water level

in November 2011

Shallow Well data for Kothapalli watershed

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.00.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

24-07-1998 06-12-1999 19-04-2001 01-09-2002 14-01-2004 28-05-2005 10-10-2006 22-02-2008 06-07-2009

Ra

infa

ll (

mm

)

Dep

th o

f w

ate

r b

elo

w s

urfa

ce (

m)

Date

Well ID 1

Well ID 2

Rainfall (mm)

6

7

8

9

10

11

12

13

14

15

16

5-31-12 6-20-12 7-10-12 7-30-12 8-19-12 9-8-12 9-28-12

De

pth

of

wat

er

BG

L (m

)

Date

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

31-05-2012 20-06-2012 10-07-2012 30-07-2012 19-08-2012 08-09-2012 28-09-2012

De

pth

of

wat

er

abo

ve t

he

se

nso

r (m

)

Date

Groundwater level

fluctuations In deep

well (upper left) and

open well (lower right)

MODEL CALIBRATION AND VALIDATION

Most sensitive and uncertain model parameters would be calibrated Saturated hydraulic conductivity of UZ layers

Surface roughness coefficient and detention storage

Hydraulic conductivity and specific yield of SZ layers

ET parameters in the model – C1, C2, C3

Calibration Deep and open wells continuous groundwater level data (June 2012-

May 2013)

Runoff and monthly open wells groundwater level data for 1999-2007

Daily GW level data from deep and open wells (July 2011-June 2012)

Soil moisture data (June 2012-May 2013)

Validation Deep and open wells continuous groundwater level data for Monsoon

season, June 2013-Dec 2013

Runoff and monthly open wells groundwater level data for 2008-2013

Daily GW level data from deep and open wells (July 2012-Dec-2013)

Soil moisture data (June 2013-Dec 2013)

GROUNDWATER USE AND CLIMATE CHANGE SCENARIOS

16 GCMs simulated and downscaled AgMIP scenarios for 2010-2030 and 2040-2070 period (A2 and B1 emission scenario – or RCPs)

Future groundwater use

Historical trend in number of wells, relevant literature and experts opinion

Crop and water management scenarios would be developed based on the results of climate change and future groundwater use scenario results

Saturated and unsaturated zone fluxes and groundwater levels under different scenarios would be analyzed for monthly/seasonal and annual changes in groundwater recharge and availability

CROP AND WATER MANAGEMENT SCENARIOS

Development of appropriate management scenarios according to the quantitative effects on groundwater recharge and levels

Crop management

Change in planting date

Switch to less water consuming crops

Irrigation Management

Deficit irrigation (whole season or during certain stages)

Switch to more efficient irrigation (e.g. from flood -efficiency 40% ,to drip- efficiency 90%)

Model simulated outputs such as saturated and unsaturated zone fluxes, would be analyzed to quantify the effects of these scenarios on groundwater recharge and levels

GROUNDWATER SURVEY AND DEVELOPMENT AGENCY (GSDA) REPORT

“In some districts from Western Maharashtra,

where groundwater level increased after the

implementation of water conservation

schemes like check dams, percolation tanks

among others. With increased groundwater

level, farmers shifted to cash crops like

sugarcane, grapes and pomegranate farms-

where water requirement was higher. Within

couple of years, the groundwater level

went down more than it was earlier

because of the excess withdrawal of

water.”

Suresh Khandale, Additional

director, GSDA