The diagram illustrates ways of protection residential areas from floods.
Looking from an overall perspective, there are two different methods that can be implemented in order to succeed: either making a stopbank, or build raised buildings.
To begin with, in the area with a stopbank, a small man-made hill which is built near a river to prevent the river from overflowing its banks. This mound is able to keep more than 100-year flood level, and there is a floodgate under the stopbank to let internal runoff out when its level is high. In addition, houses are built on short piles to prevent them from sinking in waters of internal pondings.
Houses built in areas without stopbanks are raised on high stilts for 300 mm from 100-year flood level. These measurements are calculated carefully and called freeboards.