Landscape pattern optimization of small watershed based on water purification (Danjiangkou reservoir area, China)

Abstract

In recent years, landscape pattern optimization has been regarded as a cutting-edge science in various fields, and basin hydrology is no exception. Its effect on basin water purification has also been focused on. Based on the analysis of land use types and landscape patterns in the Danjiangkou Reservoir Basin, and combined with the determination of water quality indicators in the Danjiangkou Reservoir Basin, the relationship between the spatial pattern of Landscape Morphology and water quality was studied; It is found that among the basic characteristic indicators of many basins, the main influencing factors of water quality with high Variable importance for the projection (VIP>1) are IJI (Interspersion and Juxtaposition Index), COHE (Patch Cohesion Index), AI (Aggregation Index), PD (Patch Density), ED (Edge Density); Using PLSR (Partial Least Squares Regression) analysis, the main influencing factors of water quality were discussed. It was found that there was a significant negative regression relationship (Rc < 0) with CODMn (permanganate index), TP (Total Phosphorus), TN (Total Nitrogen) and NH4+-N (ammonia nitrogen) in the basin, and the influencing factors were topographic humidity index, topographic relief, slope, and forest area; The landscape patch connectivity index was used to determine the ecological source areas in the Danjiangkou reservoir basin that have improved connectivity and need to be protected; The priority of ecological corridor construction and protection was determined; With the help of the minimum cumulative resistance model, the ecological corridor between various ecological sources is constructed; The ecological grips on the ecological corridor are identified. In order to provide technical support for the optimization of landscape configuration for the purpose of water quality purification in Danjiangkou reservoir area.