Study on the changes in vegetation structural coverage and its response mechanism to hydrology

Vegetation is an important factor that affects the hydrological process of a watershed. In recent years, the vegetation in the hilly and gully regions of the Loess Plateau has undergone significant changes, which have greatly changed the relationship between rainfall and runoff and sediment in the region. A single vegetation cover index cannot represent the important impact of vegetation grade on the effectiveness of soil and water conservation. It is of great scientific significance to deeply study the influence of the vegetation structure change mechanism in the hilly and gully area on the hydrological process of the watershed. In this article, a typical watershed in the loess hilly and gully area is used as the research object, and the method of combining field sampling experiment and remote sensing inversion is used to establish a vegetation index remote sensing model reflecting the vegetation canopy cover and litter. The impact of changes in vegetation structure on hydrological processes is quantitatively assessed. The results show that the more annual precipitation in the basin, the more sensitive the runoff coefficient is to changes in structural vegetation index. The greater the rainfall intensity, the weaker the sensitivity of the sediment yield coefficient to changes in structural vegetation index. The use of remote sensing data to retrieve the underlying surface vegetation still has the problem of the scale effect. It is necessary to further use remote sensing data with a higher spectral resolution to carry out field observations at different scales to improve the applicability of this method in a wider range of watersheds.