A method to quantify the ecological benefits of river treatment projects with monetary values.

The ecological benefits of river treatment projects are remarkable, and quantifying them is of great significance for conducting national economic evaluation. However, the ecological benefits of river treatment projects have not yet been fully comprehended, and the existing evaluation methods are unable to evaluate the ecological benefits in monetary indicators. This study intends to quantify the monetary value of the ecological benefits of river treatment projects. Firstly, the ecological benefits of river treatment projects were categorized into direct and indirect ecological benefits, and they were defined respectively. Considering the changes in land use types and the corresponding ecosystem services value (ESV) resulting from river treatment projects, a calculation method for direct ecological benefits was proposed. The indirect ecological benefits of river treatment projects are reflected in the reduction of ecosystem damage caused by floods through enhancing flood control standards. A function for calculating the loss rate of floods to ecosystems was constructed, and a calculation method for ecological losses caused by floods was proposed in combination with the ESV. Subsequently, to improve the computational efficiency, the frequency method was simplified to calculate the indirect ecological benefits, and the calculation method for the total ecological benefits of river treatment projects was proposed. Taking the Jialu River treatment project as an example, its direct, indirect, and total ecological benefits were calculated to be 2.39, 6.86, and 9.25 million yuan/year, respectively. This method can not only quantify the ecological benefits of river treatment projects but also provide a reference for the ecological benefits assessment of other water conservancy projects.