Evaluation of the value of water retention service in the middle and upper reaches of Hunhe River based on SWAT Model.

The upper and middle reaches of the Hunhe River, with forest coverage rate up to 68%, is an important water source protection area in Liaoning Province. Based on the SWAT model and shadow engineering method, we aimed to estimate the function and service value of water retention in the upper and middle Hunhe River basin from 2000 to 2019, to analyze the spatial heterogeneity, and to provide a scientific basis for the ecological compensation and ecological restoration of the region. Our results showed that the function and service value of water retention in the upper and middle reaches of the Hunhe increased first, and then decreased from 2000 to 2019.