A simulation of crop choice was performed to examine the feasibility of introducing diversified farming systems, coexisting with seasonal floods, as an alternative to triple rice cropping system in the floodprone Mekong Delta in Vietnam. A combination of 1.78 to 1.88 ha of double rice cropping and 0.12 to 0.22 ha of upland cropping can achieve an equivalent income or profit from 2 ha of triple rice cropping. Farmers evaluated the full-dike system positively in terms of both economic aspects and living conditions. Some farmers recognized that full flood control might have worsened the natural environment and reduced soil fertility resulting in declining rice yields. To establish a smart flood control system as an adaptation strategy against expected climate change, the following measures must be undertaken: (1) sensitize farmers to the increasing climatic risk in the near future and longterm adverse effects of intensive triple rice cropping; (2) offer alternative environmentally sound and economically profitable farming systems; and (3) develop institutional design for well-coordinated gate and pumping operations both at dike units and in canal network systems. Keywords: adaptation strategy, climate change, economic simulation, triple rice cropping, dike system JEL Classification: Q01, Q12, Q25