Climate change is widely recognized to have an adverse effect on both short and long-term,especially under uncertainty of water resource availability. Water is not only affecting drinking and foodavailability, but also services and industrial manufacturing departments those are significant to oureveryday-life. To retain water resource service under such an uncertainty and economics recessioncircumstance, governor has to determine an appropriate policy from a single or a combination of multipledemand-reduction and supply-increment options, which is not an easy task for the governor.This paper describes designing of a system to answer the best water resource policy under a givenconstraint conditions, e.g. cost, ease to implement, social and economic scenario, etc. A final solution isdetermined from considering a vast of number of scenarios from all possible options combinations anduncertainty from climate change prediction, and give the best scenario back to governor in real-time. In eachscenario, water resource equilibrium from predicted demand and supply in future is calculated, based on agiven (generated) policy, economic and social effects on water shortage are determined.A modern GPU computing and cloud computing technology are integrated in order to serve the mostconvenient experience to the system users. Adopting GTX-Titan GPU, the system could serve about 1,600,000scenarios per minute, which is about several ten thousand times faster than the previous system framework.This enable governors using the system to make a decision on the fly.