That was very cool. So I went ahead and started modeling. I remember I did most of the model planning when I was visiting MIT during summer in 2012. It was quite stressful because there was not much left before submitting my thesis in December. But at the same time, it was very fun to create something original.
After simulating water demand and supply for the 21st century, we also used a method called Analytic Hierarchy Process to rank the plans to augment Singapore's water supply. The figure below shows the performance of each plan as a function of cost index (higher means more costly) and self-sufficiency index (higher means more water supply). It is clear that investing in underground reservoirs cost too much and bring too little water, compared to other alternatives.
Adapted from a study on Sustainable Water Resources Management in Singapore
(click the link to read the full journal article)
After defending my thesis in Dec., 2012, half an year ahead of my peers, we managed to publish some preliminary results in a conference paper and the final results in Water Resources Management, a wonderful journal for this subject matter.