Application of landscape ecological decision and evaluation support system on flood mitigation strategies

While flood mitigation measures are needed in flood-prone areas, some may impact the environment, for example by causing habitat fragmentation. As flooding issues nowadays are more complicated and should be discussed taking multidisciplinary considerations into account, the purpose of this study was to evaluate the effects of land use changes on flooding, landscape pattern, and ecological resources as a whole, based on past environmental changes and trends in future development, using the concept of the Landscape Ecological Decision and Evaluation Support System Model (LEDESS). Yunlin County, one of the demonstration sites of the Regulation Project of Flood-Prone Areas, proposed by the Water Resource Agency of Taiwan in 2005, was studied. We designed three scenarios, i.e. Scenario A for the current situation, Scenario B for the government policy, and Scenario C as a sustainable policy integrating room for water. We used people, planet, and profit as the indicators to understand the consequences under different scenarios. The results indicated that lots of land will be abandonedin the near future due to flooding regardless of whether or not mitigation measures are adopted. That is to say, the coastal area will turn into a wetland area through natural processes. Hence, we need to reconsider land use strategy.