Flood control. We would like to think we have done good work on abating flooding, but there are more ways to build on what we are doing. Tulsa, Oklahoma in the US was severely affected by flooding until it implemented an array of solutions.
It is necessary to develop master drainage plans for separate areas and also for multiple areas at once. Grassland and open recreation spaces, urban and rural, can be lowered to act as temporary ponds in the control of flood water.