THESIS
2018
xii, 113 pages : illustrations ; 30 cm
Abstract
There is overwhelming evidence that climate change can alter the precipitation patterns,
which in turn will affect the quantity and timing of freshwater availability and also the
reservoir operations. Moreover, the exisiting approaches for reservoir operation correspond
to historical conditions, and do not account for future climate non-stationarity. In this thesis,
we explored strategies to combat the effects of climate variablility and extremes on reservoir
operation and freshwater supply.
First, we examine an approach to mitigate the effects of reservoir supply uncertainty
due to climate variability. We develop a joint water supply model by combining the
operation of a reservoir with wastewater recycling plants and seawater desalination plants.
In comparison to stand-alone...[
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There is overwhelming evidence that climate change can alter the precipitation patterns,
which in turn will affect the quantity and timing of freshwater availability and also the
reservoir operations. Moreover, the exisiting approaches for reservoir operation correspond
to historical conditions, and do not account for future climate non-stationarity. In this thesis,
we explored strategies to combat the effects of climate variablility and extremes on reservoir
operation and freshwater supply.
First, we examine an approach to mitigate the effects of reservoir supply uncertainty
due to climate variability. We develop a joint water supply model by combining the
operation of a reservoir with wastewater recycling plants and seawater desalination plants.
In comparison to stand-alone reservoir operation, the proposed joint system is less
vulnerable to climate uncertainties, and is also cost effective. The joint model is operated on
a daily time step following a cost-based priority based rule to govern the water release or
production from the facilities. The joint system is modeled as a multi-objective optimization
problem with the double objectives of minimizing risk and vulnerability, subject to a
minimum limit on resilience and water quality, capacity and budget constraints. The system
is optimized using a genetic algorithm. The joint model is applied to two hypothetical but
realistic cases based on India and California, considering various scenarios of costs and
budget. The results show the joint operation to improve water supply security. Even though
the joint operation requires an additional cost over that of stand-alone reservoir operation,
this cost is significantly smaller than the case when the three sources are operated separately
in a non-integrated fashion. This study contributes to a greater quantitative understanding of
desalination as a redundancy measure for adapting water supply infrastructures for a future
of greater scarcity and uncertainty.
Next, we examine the problem of reservoir operation under future climate
uncertainty. To this end, we develop an adaptive, forward-looking reservoir operation model
to account for the changing hydroclimatic conditions of future. The forward-looking
optimization model with sequential decision-making ability is developed as a linear
program, and solves given an ensemble forecast of future streamflows. The model executes
on double time steps (daily and weekly) to simultaneously capture the effects of both the
occurrence of extremes and long-term seasonality of flows. We run the model iteratively
with rolling forecasts to obtain the optimal system behavior over the operating horizon.
Finally, using the forward-looking reservoir operation model developed in the above
approach, we compare the performance of three strategies for adapting the operations of a
theoretical Indian water supply and flood control reservoir under future climate extremes.
We investigate the benefits of (i) expanding the reservoir capacity, (ii) introducing
wastewater reclamation and seawater desalination to augment supplies, and (iii) improving
real-time streamflow forecasts for more optimal decision-making. Our results across past
and future climate scenarios suggest that of the three adaptation options, improved
streamflow forecasts to be the most effective in mitigating both excess spill and water
shortage, and supply augmentation by wastewater reclamation and seawater desalination to
be least effective. However, we still find the roles of supply augmentation measures and
reservoir capacity expansion to be significant in reducing system failure, especially in future
with increases in flow extremes. This work may have significance for policy makers
interested in climate change adaptation of water resources.
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