Exploring the Spatial Development of Watersheds and the Allocation of Responsibility for Stormwater Runoff from the Perspective of Ecological Efficiency Based on the DEA Method

Urbanization leads to many stormwater runoff problems. Additionally, due to unbalanced regional development, it has become particularly difficult to clarify responsibility for runoff. Reasonable and effective methods for evaluating ecological efficiency can be used as references in evaluating the coordinated development of watersheds and allocating responsibility for runoff. Data envelopment analysis (DEA) is a particular type of multiple-criteria decision analysis. In this paper, a two-stage DEA model for evaluating the efficiency of the two-stage system of traditional production and environmental protection was constructed. Based on this model, a method for distributing responsibility for stormwater runoff was established. The main empirical results are as follows: (1) the ranking of the integrated ecological efficiency of the regions in the Dajiaxi watershed is midstream (22.3873) > downstream (20.6629) > upstream (4.6383); and (2) the downstream, midstream, and upstream regions are responsible for 72.90%, 8.30%, and 18.80% of the total reduction in stormwater runoff, respectively. This study provides solutions for stormwater risk management and the balanced development of watershed space.