tailieunhanh - Two-dike system along Vietnam coast

To get insight in the costs of a 2-dike system along the coast and to find optimum solutions for flood defence, a simple but comprehensive model is made. Total costs are calculated based on loads and strength of the dikes. | Two-dike system along Vietnam coast Gerrit Jan Schiereck1 and Nguyen Ba Quy2 Abstract To get insight in the costs of a 2-dike system along the coast and to find optimum solutions for flood defence a simple but comprehensive model is made. Total costs are calculated based on loads and strength of the dikes. Keywords two dike system coastal defence coastal zone management sea dike 1. Introduction A two dike system is sometimes mentioned as a good tool to improve the safety against flooding along the Vietnam coast. Little has been done until now to quantify the system and to see if and where there is some optimum in the choice between one or two dikes. To get some idea a simple program has been made to explore the properties of this system. Basically the system consists of two dikes with space in between. The seaward dike is named here dike 1 and the landward dike dike 2. Main question is how to design a dike system such that maximum protection of the area behind the system is reached against minimal costs. Different approaches are thinkable like there is only one dike with an amount of overtopping which is acceptable for the hinterland to be protected. dike 1 should be just strong enough to survive a typhoon and high enough to reduce the waves for dike 2 which is somewhat higher to withstand the water level in between the two dikes and which gives the same amount of overtopping as in the first case. the area between the dikes is large enough to store all the overtopping water of dike 1 during a typhoon dike 2 is just high enough to withstand that water level which depends on the size of the area in between and has again the same overtopping to the hinterland. With all variables involved it is already so complicated that a structured approach is necessary to overview all possible combinations and to find a minimum in total costs. Completeness is here more important than accuracy or scientific value therefore a program has been made which is simple but in which .