Application Of Fuzzy Analytic Hierarchy Process On Decision-making For Stormwater Management Practices

With the acceleration of urbanization, sharp rise of urban imperviousness appearsand leads to significant changes in the natural hydrological cycle. At the same timestormwater peak flow increases, and combined sewer system overflows frequently,which threatens human lives and public property. A lot of facts show that traditionalstormwater management mode has turned out to be unable to ensure the normaloperation of the drainage system. It’s urgent to introduce stormwater managementconcept home and abroad. Given that there are a great number of stormwatermanagement practices and numerous complex factors involved in the decision-makingprocess, it’s to introduce fuzzy Analytic Hierarchy Process to make strategic decisionfor best stormwater management practices.Firstly, this paper analyzed and characterized the structures, features, functions,maintenance and management requirement, and constraints of typical stormwatermanagement practices in detail. Stormwater management practices assessment systemwas constructed with the criteria about site suitability, performance evaluation, costand maintenance requirement, so as to facilitate analysis of various factors affectingdecision-making. The assessment system can provide preliminary reference andfoundation for stormwater management practice comparison.Then, fuzzy Analytic Hierarchy Process was introduced based on combinationsof fuzzy multiple attribute decision and core idea of Analytic Hierarchy Process.Fuzzy consistency judgment matrix was established to overcome drawbacks oftraditional method. Accurate quantitative description and consistency was guaranteed.Then, detailed decision-making steps were elaborated for decision-making ofstormwater management practices.Finally, hierarchy analysis structure for stormwater management practice was setup on the basis of analyzing stormwater management practice database. Fuzzyconsistency judgment matrixes were constructed under constraints of different factors.Weigh vectors were extracted using character root method. Stormwater managementpractice decision matrix was found. Then, combined with case study, influence factorsimportance was investigated to set up judgment matrix. Final strategic decision-making was built on combination of fuzzy multiple attribute decision matrixand vector for different factors. Stormwater management model PCSWMM was usedto test and verify the effectiveness of the fuzzy Analytic Hierarchy Process.Results show that the FAHP can be applied effectively to decision-making ofstormwater management practices. FAHP achieves quantitative description ofcomplex factors, and avoids tedious work for matrix consistency judgment. Under the"cut peak flow" criteria, infiltration basin and porous pavement work best, but theeffect of vegetated filter strip and sand filtration system are the worst. Under "TSSremoval" criteria, bio-retention cell and sand filtering system work best, and vegetatedfilter strip and grass swale worst.