Ex-post evaluation analysis of flood control engineering system based on grey relation projection method

For those modern construction projects in the large-scale flood control engineering system built with great investment, they are of great importance. In the evaluation of these projects, many of their effects are concerned. To study the EX-Post Evaluation Analysis (PEA) of Flood Control Engineering System (FCES) from the viewpoint of sustainable development is an urgent need for water resource conservancy. According to the systems engineering theory, economics, environmental and resources economics, and grey theory, this article analyzes the post evaluation index system of flood control engineering system and establishes a new method named grey relation projection for evaluating the comprehensive effects of FCES based on Multi-Criteria Decision Making (MCDM). It is applied in the proposed model to quantitatively calculate the synthetic evaluation value of the system, with the weight of index calculated by Delphi method. The effect analysis includes economic benefit, ecological and environmental benefit, and social benefit. The development trend of the comprehensive benefits in time dimension and the ordering optimal selection of the engineering project in space dimension were obtained, in studying PEA of flood control engineering system in Hunan Province. It has shown that this new approach has significant advantage in intensifying the construction and investment management of hydraulic engineering project.