Transcript Impacts of climate changes, case of Jaisamand - Asian G-WADI

Asian G-WADI Workshop
Tehran, Iran
20th – 23rd June 2011
Impacts of Climate Change:
Case of Jaisamand Lake Catchment
Om Prakash Sharma
Wells for India
Completed 23 years of working in Rajasthan, India
11 Semi Arid and Arid districts of Rajasthan
24 Non Governmental Organizations – NGOs
partner agency
Over 23 years we have worked in more than 900
villages of Rajasthan, India
Drylands are inhabited by approximately 2 billion people globally
accounting for nearly 40% of the world’s population.
Wells for India supporting
Rainwater Harvesting,
Livelihood Enhancement,
Women Empowerment,
Health and Education Projects
Emergency Responses ( Drought, Flood and Earthquake)
Challenges
63 million people, 75 % population is rural, High population growth rate,
61 % of the land area is sandy desert. Rainfall 100 mm to less than 400 mm. Summer
temperature may be high as 49 to 50 deg. Semi arid region – rainfall 500 to 650 mm.
Approximately, 40% of Rajasthan (eastern part) is occupied by hard rock.
Limited fresh water zones.
Women suffers a most, walk 8 – 10 Km daily.
Underground salinity and high level of fluoride.
Due to surface water scarcity there is a large dependency on groundwater yet recharge
characteristics are poorly understood.
Rajasthan has a strong tradition of water harvesting
Low Literacy rate of the state is, in desert and semi desert areas, Female: 44 4%
Recurrent drought
Water, food and Fodder shortage.
Distress Migration is common.
G-WADI Pilot Basin :
Jaisamand Lake Catchment
Legend
WATER BODIES
GANGESHWAR WATERSHED
DHARIAWAD BLOCK
GIRWA BLOCK
SALUMBAR BLOCK
SARADA BLOCK
VALLABHNAGAR BLOCK
BARISADRI (CHITTOR) BLOCK
DUNGLA (CHITTOR) BLOCK
Jaisamand
Lake Catchment
Jaisamand
Lake
The Lake was originally created in the early
18th century to enhance the conservation of
wildlife.
Jaisamand Lake with a gross capacity of
414.6 Mm3 and live storage of 296.14 Mm3, is
the Asia’s second largest artificial water
storage reservoir.
The gross basin area up to the Jaisamand dam
site is 1787 km2
Main features of Jaisamand Lake Catchment
Ground elevations ranges between 300 m to 650 m above mean sea level.
Mean Rainfall 650 mm. Falls during months of June – September (94%) and typically as
several intense storms and light showers
The rainfall is spread over a period of about 20-30 days
The rocks form part of the Archaean Aravalli and Delhi Super group – a complex series of
highly metamorphic igneous, volcanic and sedimentary rocks. These are weathered along
joints and fractures to form an overlying regolith aquifer of varying thickness.
Out of total Lake Catchment area only 27 % is cultivable area and rest 57 % is under no
arable, 19 % is under forest land and just 7 % is under pasture land.
Wells are the major source of irrigation covering more than ¾ of the total irrigated area
Maize, Wheat, Gram and Mustard are the major crops grown in the area
The Lake Catchment area is composed of 5 main “blocks” with 419 villages.
The basin is predominantly inhabited by tribal communities and some 30% currently live
below the poverty line.
Main issues
Lack of sustainable food and fodder security system and non-availability of non-farm based
economic activity, problems of tribal living in the catchment gets aggravated during
droughts
there are main issues relating to people and livelihoods in this area where the improved
scientific knowledge and understanding around water can provide lasting benefit;
Related to water resources there is a need for more (and more reliable) hydrological and
environmental data,
There are also important management issues relating to water resources and capacity
development. Traditional methods of rainwater harvesting are an important factor in
management in the basin.
Climate Change / Variability
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RAINFALL
TEMPRATURE
WIND VELOCITY AND DIRECTION
HUMIDITY
ATMOSPHARIC PARAMETERS
RAINFALL VARIABILITY
The analysis of rainfall data in drylands indicates that drought occurs once in every 2 to 3
years which is leading to promotion of the idea of transportation of water from large
distances and completely neglecting the need to improve the responses of small scale
water harvesting systems.
Poor families living in drylands are already struggling to cope with the changing and
unpredictable weather pattern and this will be worsened by climate change / variability.
According to the Indian Institute of Tropical Meteorology, Pune, rainfall has been increasing
in the Rajasthan desert since 1973, though marginally. What has also made a difference is
the decreasing rain spells, not just in Rajasthan but in Punjab and Gujarat. As a result, the
intensity of showers is greater.
Less rainfall and longer dry spells mean soil water conservation measures may fail to
increase soil moisture sufficiently for crops. Ground water recharge may reduce if
infiltration decreases. Ponds, tanks and reservoirs may not fill up enough to support
agriculture and drinking demand.
Or many may be at risk of damage from more floods. Larger, more intense floods could also
cause catastrophic large dam failures.
Water Harvesting Structures Type Possible biophysical risks associated with changes in
climate
Reservoirs, Ponds, Naadi, Tanks  Reduced inflows resulting in longer periods between filling
and Rainwater harvesting Tanka
 Higher evaporation, depletion in water levels
 Infrastructure damage due to higher floods
 Improved habitat for diseases vectors ( e.g. malaria)
 Increased risk of salinization and eutrophication
 Increased siltation.
 High runoff and erosion hazard during stormy cloud
bursts.
Soil moisture
 Reduced infiltration resulting from modified rainfall
intensities.
 Water logging resulting from modified rainfall intensities
and duration.
 Longer dry periods resulting from altered temporal
distribution of rainfall
 Depleted soil moisture arising from higher evaporative
demand
 Soil erosion resulting from modified rainfall intensities and
duration
 Reduced soil quality due to modified rainfall and
temperatures.
Aquifers
 Reduced recharge resulting from modified rainfall
intensities.
 Reduced recharge from land cover modification.
 Reduced recharge from increase soil moisture deficits
 Increased percolation through frequent flooding.
Climate Change and Adaptations
• TRADITIONAL WATER HARNESSING SYSTEMS
• MIXED FARMING SYSTEM
• MIGRATION
Wells for India work – a beginning
Developed a simple scientific monitoring system to gauge the impact of water harvesting
works.
Regular monitoring of water level data in wells, crops production, income etc. by local
villagers (initial training to village people given by NGO partners)
Strengthening of observation Network
Local village youth measuring the rainfall in
Savana Watershed
Local village youth measuring the rainfall in Savana Watershed
Annual rainfall pattern in Bodimagri village
of Jaisamand Lake Catchment
( village no 18 )
Year
Bodimagri
Rainfall (mm)
Rainy days
2004-05
592
27
2005-06
557
28
2006-07
1047
40
2007-08
580
31
2008-09
438
26
2009-10
449
24
2010-11
624
36
HyDIS GWADI MapServer
Measurement of water levels in open wells by village youth in Savana
Watershed
Estimates of groundwater recharge within the Gangeshwar Watershed were determined
using Chloride Mass Balance..
Recharge rates estimates in the Gangeshwar ranged from 1.1 to 49.6 mm/yr
All of the recharge rates calculated within the Gangeshwar are under 10% of the total
annual rainfall and coincide with other recharge rates from Rajasthan
Need for Adapting Water Harvesting / Management
to Climatic Change / Variability
A. Revisit water storage options
B. Manage water demand
C. Increase water productivity
D. Transform water governance
With the UNESCO-GWADI initiative in the lake catchment, the overall understanding of the
hydrological aspects has been enhanced. The initiative has motivated Wells for India and
partner organizations staff to consider the issues in a more logical way and to use scientific
information within the society.
The water level monitoring for last 6 years has led to an increase in the awareness of local
youth in the villages to see the significant inter annual changes. Along with this there has
been a growing awareness of the impacts of small water harvesting works on local
surroundings.
Other scientific monitoring such as infiltration test, geological surveys and stream gauging
has involved the local villagers and helped them in broadening their outlook and
understanding of the natural environment. It has been impressive to record that the local
communities became enthusiastically involved in all the survey work Some effort was made
to explain what was being carried out in simple language and to have good discussion
Wells for India and its partners have adopted some simplification of scientific monitoring
systems so that many of the tasks can be understood and possibly carried out by the local
community who actually are the main beneficiary of all works.
Thank you for your kind attention