Application of fuzzy theory and PROMETHEE technique to evaluate suitable ecotechnology method: A case study in Shihmen Reservoir Watershed, Taiwan

With the increase in industrial development and improper land uses, Taiwan has faced the extinction crisis and is seeing the signs of nature, revenge in the forms of frequent landslides, floods, and debris flows in recent years. The government has strongly promoted the concept of ecotechnology in the hope of maintaining the ecosystem and its integrity. However, the application of ecotechnology is still in its infancy, so there is currently no objective evaluation standard to assess its effectiveness. Deficiencies in the scientific approach to quantify the results are due to current disputes and bottlenecks in its implementation. In order to seek reasonable and feasible methods to overcome the deficiencies in the implementation of the scientific approach, this study collected domestic and international ecological evaluation models to develop innovative processes that utilize ecological, safety, and cost indices. First, the commonly used ecotechnology methods for river embankment were acquired from the governmental departments. Second, the ecological, safety and cost indices for the acquired ecotechnology methods and construction sites were analyzed and quantified using fuzzy theory. Third, indices of ecotechnology methods were linked with those of construction sites for the PROMETHEE technique evaluation for suitable ecotechnology method selection. A practical construction case located in Shihmen reservoir watershed was chosen for evaluation and verification. The results show that the developed model can provide useful information for decision making while performing ecotechnology engineering.