Significance Statement
Researchers from Heriot-Watt
University Scotland in collaboration with Cranfield University
England and IIT-Roorkee in India are collaborating on a
multi-institutional project titled “Mitigating climate change impacts on Indian agriculture through improved irrigation water management (MICCI)”.
They are investigating the effects of projected climate change and its
variability on irrigation water security in India and evaluating the
effectiveness of better irrigation and water management strategies in
mitigating any resulting water shortages thereby improving the
productivity of the available water.
The authors in the hydrology paper used
HYSIM rainfall-runoff model which uses rainfall and potential
evaporation data to simulate the hydrological cycle (surface runoff,
percolation to groundwater and river flow) on a continuous basis. This
enabled the impacts of projected changes in climatic attributes
(precipitation, temperature, etc.) on future water resources
availability in the case study Beas River Basin in Himachal Pradesh to
be simulated. Extensive reservoir simulation studies on the
multi-purpose Pong reservoir in the Basin showed that dwindling water
availability in the future will lead to significant deterioration in the
performance of this major water resources infrastructure unless
improvement in its operational management is carried out. Examples of
such improved operational practices were developed and tested with
resounding success. Although applied to an Indian Basin, the methodology
is sufficiently generic that it can be extended to other south Asian
countries. This paper should improve our understanding of the climate
change water problem and offer solutions that are robust and effective
for Indian irrigators.
This study has evaluated the effects of
improved, hedging-integrated reservoir rule curves on the current and
climate-change-perturbed future performances of the Pong reservoir,
India. The Pong reservoir was formed by impounding the snow- and
glacial-dominated Beas River in Himachal Pradesh. Simulated historic and
climate-change runoff series by the HYSIM rainfall-runoff model formed
the basis of the analysis. The climate perturbations used delta changes
in temperature (from 0° to +2 °C) and rainfall (from −10 to +10 % of
annual rainfall). Reservoir simulations were then carried out, forced
with the simulated runoff scenarios, guided by rule curves derived by a
coupled sequent peak algorithm and genetic algorithms optimiser.
Reservoir performance was summarised in terms of reliability,
resilience, vulnerability and sustainability. The results show that the
historic vulnerability reduced from 61 % (no hedging) to 20 % (with
hedging), i.e., better than the 25 % vulnerability often assumed
tolerable for most water consumers. Climate change perturbations in the
rainfall produced the expected outcomes for the runoff, with higher
rainfall resulting in more runoff inflow and vice-versa. Reduced runoff
caused the vulnerability to worsen to 66 % without hedging; this was
improved to 26 % with hedging. The fact that improved operational
practices involving hedging can effectively eliminate the impacts of
water shortage caused by climate change is a significant outcome of this
study.
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