CLIMATE AND LULC CHANGE SCENARIOS TO STUDY ITS IMPACT ON
HYDROLOGICAL REGIME
5.2 Aggarwal’, Vaibhav Garg, Prasun K. Gupta, Bhaskar R. Nikam and Praveen K. Thakur
Indian Institute of Remote Sensing, Indian Space Research Organisation, Dept. of Space, Govt. of India, 4, Kalidas
Road, Dehradun— 248 001, Uttarakhand, India - (spa, vaibhav, prasun, bhaskarnikam, praveen)@iirs.gov.in
Commission VIII, WG VIII/4
KEY WORDS: hydrology, climate, modeling, impact analysis, remote sensing, GIS
ABSTRACT:
Climate change, whether as a natural cycle variability and/or due to anthropogenic reasons, is affecting and likely to further affect the
water resources, which is a vital necessity for existence of life form. The predicted intensification of hydrological cycle would
change all of its constituents both in time and space domain. This is a long term phenomenon and the necessity is to understand the
intensity of the effects on various aspects of water resources by way of scientific studies backed by the available field data.
Therefore, in the present study, the impact of climate and land use land cover change on entire India under different assumed
plausible hypothetical scenarios has been studied. These scenarios were developed by increasing; temperature by 1, 2 and 3C;
rainfall by 5, 10 and 1596; and then the combination of both. To carry out this analysis, variable infiltration capacity (VIC) semi-
distributed macroscale hydrological model has been investigated. It was found that slight change in climate may pose huge difference
on hydrological cycle and its component.
1. INTRODUCTION
Since the beginning of concern over the possible consequences
of global warming, it has been widely recognized that changes
in the cycling of water between land, sea, and air could have
very significant impacts across many sectors of the economy,
society, and the environment. The climate change and its impact
on hydrological processes are of widespread concern and a great
challenge to researchers and policy makers in this changing
environment. Moreover, understanding the hydrologic response
of very large river basins or entire country offers new challenges
and opportunities for hydrologists. The impacts of climate
change on hydrology usually are studied by defining
scenarios for changes in climatic inputs to a hydrological model
in two ways: (i) studies using GCM/RCMs directly to predict
impact of climate change scenarios (ii) studies using
hydrological models with assumed plausible hypothetical
climatic inputs (IPCC, 2001b). The three key issues confronted
here are: constructing scenarios that are suitable for
hydrological impact assessments; developing and using
realistic hydrological models; and understanding better the
linkages and feedbacks between climate and hydrological
systems. In the present analysis these issues were critically
analysed and addressed as discussed below.
The rainfall and temperature drives the hydrological cycle,
influencing hydrological processes in a direct or indirect way. A
large number of studies have been carried out to analyze the
trends of variation in these parameters over India/Indian Sub-
continent. The projections indicate that the warming would vary
from region to region, accompanied by increase and decrease in
precipitation (Sahai et al., 2003; Gadgil et al., 2004; Goswami
et al., 2006; Ghosh et al., 2009). In addition, there would be
change in the variability of climate, and changes in frequency
and intensity of some extreme climatic phenomenon. Flood
T Corresponding author.
magnitude and frequency are likely to increase in most regions,
and low flows are likely to decrease in many regions. However,
there have been very few studies addressing the issue directly,
largely due to difficulties in defining credible scenarios for
changes in flood producing climatic events. As it may be
observed from these findings, studies using hydrological model
with assumed plausible hypothetical climatic inputs would be
useful for assessing impacts of climate change on water
resources. The evolution of soil-vegetation-atmosphere transfer
schemes (SVATS) models, those are applicable to large areas
and river basins, has solved the second and third issue to large
extent. Therefore, in the present study, the impact of climate
and land use land cover change on entire India under different
assumed plausible hypothetical scenarios has been studied.
2. STUDY AREA AND ITS CLIMATE
India has been known for vast variability in availability of water
resources in the country. The main land mass of India is located
between 8°4’ N and 37?6' N latitude to 68?7' E and 97°25’ E
longitude with the geographical area of 3,287,263 km?. India is
endowed with almost all the important topographical features
such as high mountains in north, extensive plateaus, wide plains
traversed by mighty rivers and ocean in south which influence
its climate. That is why; India is a country with extremes of
climate. The presence of Himalaya has an important bearing on
the climate and water resources of the country. The Himalayan
ranges are the primary source of rivers which derive their flow
from rainfall, snow and glacier melt. Moreover, Himalayas act
as a meteorological barrier due to which the Indian sub-
continent experiences tropical monsoon. The temperature in
country varies from 47°C at many places in summer to low as -
40°C at few places in Himalayas. The rainfall distribution is
also extreme as some places receive negligible rainfall, where,
