2) Flood and storm-water inundation: Situated in the valley, the city is subject to floods and storm-water inundation during the monsoon season, but also severe drought in the dry season due to the porous limestone geology; 3) Recovery of the mother river: Channelization of the River Shuichenghe was carried out in the 1970s as a solution to inundation and flooding. The channel transmitted the storm-water from upstream but caused even more severe flooding problems downstream. Hence, the former meandering mother river became an ugly concrete, lifeless ditch and its capacity for flood retention and environmental remediation was totally lost