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Where natural high ground does not exist, sites can be raised by filling, providing the fill does not interfere with the flow of flood waters. The concept of clustering build- ings on higher ground, elevated by filling, is especially useful in metropolitan areas where a shortage of land may force the development of areas subject to low stage flood- ing. Figure 8 shows an actual case in which building sites at a shopping center were raised to reduce the flood hazard. The material used for raising the sites was taken from the parking areas thereby creating 26 shallow basins for the detention of storm water runoff. In flood fringe areas, raising the site only a few feet may achieve the de- sired results--placing the buildings above the design flood stage. Constructing new buildings without basements would facilitate flood proofing of this type since problems associated with ground-water pressure would be avoided. Flood proofing measures can be designed to blend with the overall appearance of a structure. When this is done, a structure's appearance can be preserved and in some cases even enhanced by flood proofing. Raising the Buildings The practice of elevating a building on "stilts" to provide an "open" effect at ground level can also reduce the flood hazard. If some means of access is maintained and utili- ties can continue to function, activities would not be interrupted during floods. This raising of the main floor level is practiced in much new construction through- out the country. There are examples of residential, commercial, recreational, and in- dustrial buildings which have been designed and constructed in this manner. Where land is at a premium, as in central business districts, buildings are often placed on "stilts" with parking facilities on the ground level. As may be seen in Figure 9, desirable esthetic effects such as the creation of upper level pedestrian plazas above utilitarian lower level parking areas, can be integrated into a flood protective scheme in which the lower level can be flooded without affecting the pedestrian areas and buildings. Similarly, the contemporary practice of placing me- chanical equipment on upper levels of multistoried buildings will minimize potential damage of valuable equipment and interruption of service during floods. Techniques de- signed for the more normal locations can be applied with little modification to buildings in flood plains, and result in structures which will suffer little damage. Mechanical floors on upper le....el L ~ ""=- ~ ~ ..,.". ~ ~ ---5' Figure 9.-Urban development that is compatible with a flood plain location. In this devel- opment, the uses of the building have been adjusted to avoid uneconomic flood losses. 13