The Study Of Landscape Characteristics And Construction Of Clean Basin For Xiaoxi River In Liuyang,Hunan

Based on massive investigation and study, the landscape resources and landscape index,the characteristics of forest hydrology and water qualities in small watershed of Xiaoxi river were thoroughly studied by qualitative and quantitative integrated means. Through above analyses, we can easily summarized the primary means of integrated river basin management and provided data support to it. By using the basic theory of the construction of ecological clean small watershed, combined the three line of defense theory system "ecological repair, and ecological governance, and ecological protection" and the natural conditions of low mountain-hill region in Eastern of Hunan. The management of Xiaoxi river basin ecological cleaning project is divided into three functional areas, the ecological restoration area, the comprehensive treatment area, and the surrounding area of the river （ditch）. Finally comes to the following conclusions:（1）The landscape abundance is small and there are 9 categories of landscape types in it except building, in small watershed of the Xiaoxi river. Woodland landscape is the main resource, the larger, accounting for 71.9% of all; Meanwhile, due to the larger forest landscape patches, there is a smaller landscape patch density, the maximum value of the Taohua village is also just 0.84 · ha^-1. The impact of human activities on the natural landscape has led to landscape heterogeneity outstanding, of which the most prominent is the Gaoping community, its landscape patches up to 54, Shannon diversity index of 2.35, landscape isolation 0.8617.（2）On the hand of forest hydrology watersheds, the highest broadleaf forest soil bulk density is 1.40 g · cm^-3 in the ZhuShuqiao village, followed by the Gaoping community and the Taohua village. The soil porosity is the Gaoping community> the ZhuShuqiao village>the Taohua village. The highest soil water storage is 3725.59 t · hm^-2 in the Gaoping village, followed by the ZhuShuqiao village and the Taohua village. The water-holding capacity of undergrowth and litter due to species differences in the main stand, ground cover and litter water-holding icapacity is significantly different.（3）Since conservation of forest in ZhuShuqiao reservoir, the forest hydrological effect is more prominent, and it has good water quanlity that water quality in the reservoir outlet basically reached II grade quality of surface water, river upstream near Zhushuqiao reservoir. However, the water quality effected by agricultural production and life, along the river down, even more serious water pollution, including Liuyang River Bay and Taohua village two sinks outlet water pollution is more serious which compared to the levels of pollutants Zhushuqiao water from the reservoir are exceeded, the Island NH₃-N content of 12.46mg · L^-1, TN content of 6.71 mg · L^-1, TP content of 1.97 mg · L^-1, nearly ten times more than the reservoir outlet.（4）The total area is 47.47 Km² in small watershed of the Xiaoxi river. The soil erosion area is 13.27 Km² which including mild erosion of 11.03 km², moderate erosion 1.27 km², the intensity of erosion 0.61 km², high intensity erosion 0.31 km², severe erosion of 0.05 km², the area of soil total erosion 26873.131 · a^-1, the erosion modulus of 1854 t/(km² · a^-1), and the degree of erosion is mild. The basin farmland pesticide strength of 6.43 kg·hm^-2, the average intensity of fertilizer use 224 kg·hm^-2, below the safe upper limit of the intensity of chemical fertilizer clean small watershed of 250 kg·hm^-2.（5） The basic theory and principle of ecological clean small watershed guided the construction of small watershed. The main measures, in small watershed of the Xiaoxi river, include replanting woodland 501.31 hm², forest banned 2732.57 hm², ecological interception ditch 3.31 km, ecological green manure and pesticides to promote rural living environment green, rural garbage and sewage treatment, road renovation, waterfront construction 6.87 km, artificial wetlands and river dredging and other layout.（6） Xiaoxi river of Liuyang is located in the low mountain-hill region in Eastern of Hunan.The zonal vegetation is subtropical evergreen broadleaf forest,and has high forest cover, large slope, valley flats are farmland, sloping farmland is relatively small, human disturbance of forest land is small, the ground cover is severely damaged occasionally. Soil and water loss is not serious in forest land with relatively few human activities. But there are serious pollutions on river basin water environment caused by the heavy agricultural production as well as animal husbandry. Clean small watershed management should be adapted to local conditions, soil loss control and water source protection also should be adapted together, meanwhile the government of low mountain-hill region in Eastern of Hunan should be focused on the water environment management and river dredging in order to protect the quality of water which product and live in agricultural and the demand of the draw off floodwater in southern rainy season.