Study On The Technology Of Ecological Slope For Urban River

In the paper, the condition of the main river channel slope in Huizhou City, Guangdong Province was investigated and the problems of the river channel slope were analyzed. According to the problems of the river channel slope, such as "hard tendency", low vegetation coverage, poor landscape, serious soil erosion phenomenon etc, we designed a set of technical proposals for the ecological slope and carried out a series of pilot scale experiments to discuss the practical application effect. The research drew several conclusions:(1) During the experiments, we determined the components of "soft filler ecological slope" respectively, soil matrix as the main body, plant fiber as soft aggregate, sawdust as the aggregate agent and peat as a natural slow release fertilizer and also selected the best composition ratio of it. The proportion by weight of this work material is nearly 78% of the soil matrix,4% of the plant fiber,8% of the sawdust, and 10% of peat. The matrix of plant fiber with different length has some effect on soil's erosion resistance ability, and the screening tests confirmed the length of 5cm is the best choice.(2) Eco-concrete slope consists of porous concrete skeleton and plant growth medium. The former has a good effect on runoff sewage purification. The nitrogen adsorption effect of the eco-concrete with aggregate of gravel is better than the one with aggregate of ceramsite, while the phosphorus adsorption effect is worse. From the perspective of plant fitness, we selected the most suitable semi-liquid plant growth medium which is made of 78g original soil,8g sawdust, lOg peat,5g PAM,5g slow-release fertilizer and 1L water. Germination rate and growth speed of seed in eco-concrete with aggregate of ceramsite are slightly better than those with aggregate of gravel.(3) After three months of the demonstration project, we got some results based on the investigation in the physics and chemistry character of soil as well as the vegetation characteristics in the experimental plot and the control plot. The moisture content and fertility of soil in the experimental plot are higher than the control plot; the vegetation recovery rate and vegetation coverage in the experimental plot are superior to the control plot; the lengths of the ground and underground part of plant in the experimental plot are longer than the control plot; NH3-N density of water which near ecological slope protection is lower than control group; the interception effect of SS and main nutrient in surface runoff through ecological slope is superior to that of the control group. In order to enhance this interception effect, slope decreasing or multi-layers can be taken into account.(4)Following the design in this article, the ecological slope shows good ecotope benefits, high landscape efficiency and economic applicability under extensive management. Because of its obvious feasibility in the reconstruction of the river bank slope in urban area of Huizhou City, it has good values of promotion.