Evaluation of Groundwater Environment Carrying Capacity Based on Catastrophe Theory

Evaluation of groundwater environment carrying capacity is a multi-objective, multi-criteria and multi-level comprehensive issue. Evaluation index system of groundwater environment carrying capacity was built and divided into some subsystems in accordance with each index´s inherent stratification link. Every index´s effect on carrying capacity system was obtained by normalization operations catastrophe-based, so the ultimate value of fuzzy membership function catastrophe-based, which explains the groundwater environment carrying capacity, can been calculated from the lowermost layer to the topmost layer. The method was applied to evaluate groundwater environment carrying capacity in People´s Victory Canal Irrigation District. In order to reveal outer and inner factor´s effect to groundwater system, evaluation index system was divided into 3 kinds of top-level subsystem, i.e., the development and utilization degree of water resources, economy society and eco-environment subsystem, which include 17 kinds of bottom-level sub-index. The comprehensive evaluation result catastrophe-based is 0.9282, 0.9212, and 0.9150 in 1995, 2000, and 2005 separately, and groundwater environment carrying capacity are all weak and shows a downtrend year by year along with rapid economy expanding. The result reveals that it is a fact that groundwater resources and eco-environment in irrigation district is increasingly prominent. As it is not necessary to define the weight of evaluation indexes in dynamic fuzzy comprehensive evaluation model catastrophe-based, subjectivity of the decision-making has been reduced. The examples show that the method in this paper is reasonable and feasible by fuzzy comprehensive evaluation method´s validation.