Abstract. When based on the zones of available water in storage, hedging has
traditionally used a single hedged zone and a constant rationing ratio for
constraining supply during droughts. Given the usual seasonality of
reservoir inflows, it is also possible that hedging could feature multiple
hedged zones and temporally varying rationing ratios but very few studies
addressing this have been reported especially in relation to adaptation to
projected climate change. This study developed and tested Genetic Algorithms
(GA) optimised zone-based operating policies of various configurations using
data for the Pong reservoir, Himachal Pradesh, India. The results show that
hedging does lessen vulnerability, which dropped from ≥ 60 % without
hedging to below 25 % with the single stage hedging. More complex hedging
policies, e.g. two stage and/or temporally varying rationing ratios only
produced marginal improvements in performance. All this shows that water
hedging policies do not have to be overly complex to effectively offset
reservoir vulnerability caused by water shortage resulting from e.g.
projected climate change.
Effect of reservoir zones and hedging factor dynamism on reservoir adaptive capacity for climate change impacts
