Analysis and forecast of water ecological footprint in karst area based on GRNN model

In order to reveal the driving factors and mechanism of urban ecological footprint, evaluating and predicting the degree of sustainable utilization of water resources in karst area, the change characteristics of water ecological footprint in Guiyang City from 2002 to 2014 were analyzed, according to the hydrogeological features in karst area and its correlation with the water ecological footprint, and the GRNN model was used to predict and evaluate the water ecological footprint time series. The results showed that the water ecological footprint of Guiyang city rose from 12.79 Mhm2 in 2002 to 15.74 Mhm2 in 2014, of which the variety of water volume ecological footprint was determined by the industrial water consumption, water quality ecological footprint change was determined by the ammonia emissions. The fluctuation of the water ecological carrying capacity was obvious, and the water demand was less than the water ecological footprint, which led to the coefficient of sustainable utilization of water resources was between 0.34 and 0.61. The water ecological footprint from 2015 to 2019 in Guiyang city is predicted by the GRNN model, which show that the trend of water ecological footprint first increase and then decrease, and the water ecological carrying capacity ranged from 4.315 Mhm2 to 8.038 Mhm2. But the gap between the water ecological footprint and the carrying capacity is huge; the water resources sustainable utilization coefficient is low. Therefore, the reduction of the water ecological footprint is the key to sustainable development of the water resources in Guiyang city, of which the water ecological carrying capacity is limited in karst area.