Town-Level Aquatic Environmental Sensitivity Assessment Based on an Improved Ecological Footprint Model

Although the water area is one of the six types of biologically productive land in the ecological footprint model, it is only described on its biological production not including its aquatic production function. An improved ecological footprint model was proposed to assess regional aquatic sensitivity. The water area account in the traditional ecological footprint model was expanded and modified to include the four accounting items: aquatic pollution footprint, aquatic pollutants’ carrying capacity, aquatic ecological profit and loss and aquatic ecological pressure index. Totally the procedure introduced in the sensitivity assessment includes the five steps: (1) collecting information and calculating the amount of sewage discharged into the surface water of the region; (2) calculating the ecological footprint of different pollutants by the improved ecological footprint model, and identifying the maximum value of the footprints as the final pollution footprint; (3) evaluating the ecological carrying capacity of the region; (4) assessing the degree of aquatic pollution using the indicators of ecological deficit and ecological surplus; (5) determining the aquatic environmental sensitivity level using the aquatic pollution pressure value. The assessment model was applied to analyze the town-level aquatic environmental sensitivity in the coastal areas of Jiangsu province, China. The assessment showed that the aquatic pollution footprints in the 367 towns were in the downward trend and the aquatic pollution sensitivity decreased from 2014 to 2018. The model might improve the description of the functions on providing natural resources and consuming waste in natural systems in the footprint model. The evaluation model could objectively assess the pressure status of the regional aquatic pollution sensitivity and provide some effective suggestions for decision makers on the utilization and protection of regional water resources.