He Purifying Effect Of Li River Riparian Vegetation Zones On Pollutants And Factors Affecting It

In recent years, the Li River shore with a large area of exposed riverbed dry season, flood flow to carry large amounts of sediment import Li River, riverbed erosion is serious, river floats increasing problems have become increasingly prominent. The research on these issues, ues the field investigation, shore slope with artificial drainage simulation experiments, field experiments under natural rainfall conditions, such as the effect of pollution on vegetation net from three aspects of research littoral zone, and to analyze the impact factor of Li River slope reduce soil erosion, improve the quality of the Li River Water Resources and Environment has important theoretical and practical value, as well as the Li River riparian buffer vegetation restoration and provide the basis for planning and design. In this paper, the following conclusions can be drawn:(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%),The interception effect of 3 vegetation ranked in Geum aleppicum>Suffrutescent Securinega>Pterocarya stenoptera. Under conditions of artificial drainage shore grass strips on runoff, SS interception rates were 66% and 68%, respectively, for the NH;-N、NO;-N、TP interception rates were 39%,68%,31%; and grass shore impact the runoff pH less. Compared with the bare land, the runoff, sediment of vegetation zone were reduced by 26%,24%under natural rainfall conditions. Whether single or total rainfall runoff and sediment runoff and sediment yield, the overall performance of 7# bare land> 3# Cynodon dactylon> 6# Alternanthera philoxeroides> 5# Eremochloa ophiuroides> 4# Setaria plicata.(2) 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 (P<0.01).The correlations of amount of floats with branch diameter, plant height, and number of the first grade branch were quite different species by species. And crown width could determine the amount of intercepted floats. The length of filter was the predominant factor affecting sediment deposition in filters. When the grass width to 10m for runoff interception effect of the suspension reached 88%. Besides,vegetation type was another important factor. The result indicated that vegetation conditions with Humulus and Polygonum chinense for the retention of runoff contaminants was best.In terms of intercepting sediment runoff grass strips were better than forest belt. Between the runoff rate and runoff interception interception rate of suspended solids significant linear relationship (P<0.01). Surface runoff and sediment yield and rainfall, rainfall intensity significant positive correlation.