Spatial transfer evaluation of water conservation service value and improvement in Hanjiang River Basin

Abstract

[Objective] To assess the water conservation capacity of the Han River Basin in 2020, calculate the ecological value of water conservation services, and conduct an in-depth analysis of the spatial transfer of water conservation service values among various provinces within the basin, [Methods] quantitative evaluation of the water conservation capacity of the Han River Basin in 2020 was carried out using the distributed hydrological model SWAT and the ecosystem service assessment model InVEST. The ecological value of water conservation services within the basin was calculated using the shadow pricing method. An improved break-point-field intensity model considering hydrological characteristics was adopted to analyze the spatial transfer of water conservation service values. The improved model includes the addition of a river direction coefficient to determine the hydraulic connection, optimization of transfer pathways(adjusting the starting point of transfer and setting the maximum radius), and comparison of four different transfer method. [Results] The results show that the total water conservation volume in the Han River Basin in 2020 was 30.584 billion cubic meters, with the corresponding service value reaching 31.685 billion yuan. Among the provinces, Hubei Province had the most significant water conservation volume and service value, while Henan Province was relatively lower. In terms of spatial transfer, Shaanxi Province had the largest outflow of water conservation service values, followed by Henan and Hubei; for reception, Henan Province received the most, followed by Hubei and Shaanxi. Among these, the straight-line transfer method at the outflow outlet had the strongest transfer intensity and the largest amount of transfer; the river channel transfer method at the outflow outlet had the next strongest transfer intensity and amount; the straight-line and river channel transfer method at the inflow inlet had similar transfer intensities and amounts; the river channel transfer method at the inflow inlet had the weakest transfer intensity, and the straight-line transfer method at the inflow inlet had the least amount of transfer. [Conclusion] Through quantitative evaluation and spatial transfer analysis, the spatial distribution and service value of water conservation capacity in the Han River Basin were revealed, and a comparison of different transfer method was provided, which provided a scientific basis for basin management and ecological protection.

Keywords

water conservation / value transfer / InVest model / SWAT model / water resources / flood / Han River Basin / ecological value