A Study on Plant Selection for Low-Carbon Rain Gardens Based on an AHP-TOPSIS Model

Low-impact development (LID) measures are crucial for solving water environment problems during sponge city construction. Optimizing LID measures to meet multi-objective demands is essential for achieving low-carbon and green operation of sponge cities under the goal of ‘dual carbon’. To select the optimal rain garden plants suitable for the construction of a coastal sponge low-carbon city, a set of AHP-TOPSIS applicability assessments was constructed. The assessment index system comprises three main categories of indices: economic cost, ecological benefit, and environmental adaptability. The hierarchical analysis method (AHP) was used to construct a plant evaluation system from three decision-making levels and eleven criterion levels. This system assigned weights to each index in the index system. Subsequently, the distance between the superior and inferior solutions (TOPSIS) was used to evaluate the overall performance of 14 tree species, 10 shrub species, and 12 herbaceous plant species commonly found in rain gardens in a coastal city in China, so as to identify the optimal plants to meet the target demand of low-carbon rain garden construction.