Interception effect of riparian vegetation zone on floats and factors affecting it

The existence of floats in the rivers poses serious threats to water quality and ship navigation. Vegetation in riparian buffer play an important role in the interception and filter of floats. Based on the vegetation investigation along Li River from Guilin to Yangshuo, we screened out three typical vegetation which could intercept more floats. Then, we studied the morphological parameters of vegetation and the floats intercepted by them in the selected typical plots, investigated the interception effect of three vegetation on the floats, and quantitatively analyzed the factors affecting it. This has great significance for revealing the non-point pollution control of riparian buffer zones and improving the water resource environment. The results indicated that: 1) among the intercepted floats, the amount of dried grasses was the largest (85.32%), followed dried branches (11.44%), then plastics third (2.33%), and others the least (0.91%). 2) The interception effect of 3 vegetation ranked in Geum aleppicumSuffrutescent securinegaPterocarya stenoptera. 3) The pliability of branches affected interception effects. The rigidity of G. aleppicum’s branch was best, and high rigidity could enhance the interception effect. 4) The amount of floats intercepted by a single plant has significant correlations with crown width X, crown width Y, crown area, volume of vegetation, and riverside area of the plant (P0.01). The correlations of amount of floats with branch diameter, plant height, and number of the first grade branch were quite different by species. And crown width could determine the amount of intercepted floats. 5)It should be prioritized to plant G. aleppicum in the vegetation degradation area where has slower flow, less flood and more floats in riparian buffer zones of Lijiang River, which could achieve better vegetation restoration and interception effect on floats.