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An Assessment of Climate Change Impacts on Streamflows in the Musi Catchment, India

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Relation http://oar.icrisat.org/7438/
 
Title An Assessment of Climate Change Impacts on Streamflows in the Musi Catchment, India
 
Creator Nune, R
George, B
Malano, H
Nawarathna, B
Davidson, B
Ryu, D
 
Subject Agriculture-Farming, Production, Technology, Economics
Climate change
 
Description The long-term impacts of climate change on water resources are expected to be considerable in
Southern India especially in the semi-arid regions. The effects of the changes on precipitation and
temperature are expected to alter the hydrology of catchments and ultimately water security. A complicating
factor in dealing with climate change from a water resource management perspective in India is the current
government policies that promote watershed development (WSD), a policy that promotes the capture of
runoff to increase groundwater recharge and irrigation development. In this paper the aim is to quantify the
impacts climate change and WSD will have on the hydrologic behavior of the Musi catchment Andhra
Pradesh.
Global Climate Model (GCM) predictions of future climate are too coarse for hydrological modelling and fail
to account for the most important influence on the monsoon rainfall patterns over India. In order to increase
the spatial resolution of the models, a dynamic downscaling approach was used in this research. Three
climate simulations corresponding to the IPCC-SRES A1B scenario were downscaled for the period 1961-
2098 using “Providing REgional Climates for Impact Studies” (PRECIS) regional climate modelling system.
These simulations were based on three versions of the HadCM3 global climate model that showed realistic
results for the Indian summer monsoon.
The hydrology of the catchment was modelled using the SWAT hydrologic model. The model was set up for
the entire Musi catchment in the Krishna Basin for which the model calibration and validation was carried
out at the Osman Sagar and Himayat Sagar gauging stations. Monthly and annual inflows were used to carry
out the model calibration. The model calibration and validation yielded Nash-Sutcliffe coefficients ranging
between 0.65 and 0.75, which indicate a good model performance.
The downscaled climate data was then used as forcing data in the model to carry out simulations for all three
versions of the climate projection data ((Q0, Q1 and Q14). An analysis of flows at different time slices shows
that stream flows decline in the near future (2011-40) and then an increasing trend towards the end of the
century. Under the Q1 scenario, annual stream flows show a systematic decline over the period of analysis.
The Q14 scenario shows an increase in stream flows over the next few decades followed by a decline towards
the end of the century. Potential evapotranspiration is predicted to increase for all the climate scenarios. The
reservoir component option available in SWAT was used to assess the impact of watershed development
structures in the catchment and the analysis shows that stream flows have been declining due to the growth
and impact of these structures in the catchment.
 
Date 2013
 
Type Conference or Workshop Item
PeerReviewed
 
Format application/pdf
 
Language en
 
Rights —
 
Identifier http://oar.icrisat.org/7438/1/AnAssesment_CP_ICMS_2013.pdf
Nune, R and George, B and Malano, H and Nawarathna, B and Davidson, B and Ryu, D (2013) An Assessment of Climate Change Impacts on Streamflows in the Musi Catchment, India. In: An Assessment of Climate Change Impacts on Streamflows in the Musi Catchment, India, 1–6 December 2013, Adelaide, Australia.