Study On Situation And Sustainability Assessment Of Ecological Water Use In Shanxi Province

The author firstly collected the background information of the cities in Shanxi province, such as water resources, vegetation, land use, soil and water conservation and forest resources, then made rational arrangement and screening to them. Based on analyzing and forecasting water resources situation across the province, this paper discussed the definition of ecological water use and demand, analyzed and defined the composition of the ecological water use. With the river basins, soil and water loss types, administrative divisions, the author divided Shanxi province into three ecological zones, analyzed and counted the background value of the whole province. According as plant evapotranspiration and water balance theory, the author studied the plant evapotranspiration calculation model of Fang Shan and Xi County through experimentation, and determined the coefficient of plant water consumption and demand. Combining studies on relevant aspects in Shanxi province, the author calculated the coefficient of plant water consumption and demand, and conformed water quotas of soil and water conservation by using comparative analysis to small watersheds, and then calculated ecological water use of each city in Shanxi province. The author analyzed the present situation of ecological water use by using the concept of ecological water use coefficient Cu and modulus Mu, forecasted the ecological water demand of the year 2010 and 2015 base on Shanxi ecological system construnction planning, and analyzed amount balance of ecological water use and water resources in the whole province. Meanwhile, the author constructed hierarchical structure model of ecological water use sustainable assessment by using Analytic Hierarchy Process (AHP) method, and used water supporting degree, water using-adjusting-controlling degree, water resources and economic development coordinating degree as the supporting layer, screened 16 indices as quantitative reflection of the sustainable supporting layer of water ecological water use, furthermore calculated each index weight, calculated and analyzed the coordination-utilization level of each city.he results can be summarized as follows:(1) The analysis of water resource situation shows: in the trend of surface water use (taking 1979 as the first year in series), the available surface water (S) declines logarithmically with the serial year (x), i.e., S=-5.0929 ln (x) +35.416 (R~2=0.8059). Based on this formula, it can be predicted that the available surface water supply will be 21.35×10~8m~3 in 2010, 19.09×10~8 m~3 in 2015, and 18.7×10~8 m~3 in 2020, the available ground water (G) increases linearly with the serial year (x) (taking 1979 as the first year), i.e., G=0.6087x+23.492(R~2=0.8891). According to this formula, the available ground water supply will be 38.82×10~8m~3 in 2010, 40.01×10~8m~3 in 2015, and 41.63×10~8m~3 in 2020. Water supply and consumption projections indicate that the supply was sustained and stable and the consumption continued to rise.(2) The analysis of ecological water use, water resources and precipitation balance shows that the present precipitation of water resources in the whole province is 798.38×10~8m~3, among which the quantity of water resources 93.94×10~8m~3, ecological water resources 126.39×10~8m~3 (the volumetric of precipitation ecological water use 90.42×10~8m~3, the volumetric of runoff ecological water use 16.39×10~8m~3×10~8m~3), the plant volumetric 173.79×10~8m~3, the invalid evaporation 390.25×10~8m~3. The space of translating the invalid evaporation into ecological water use is much larger. But in 2010 and 2015, ecological construction impact on water resources will increase, the ecological water consumption will increase to 178.72×10~8m~3, 261.95×10~8m~3.which quo increased 41.40% and 107.26 % than the present situation. The surface runoff will be a slight decline, and the contradiction between water supply and consumption will become more prominent with water consumption increasing.(3) In terms of the space distribution of ecological water use, forest vegetation and river distribution to a large extent determines the total consumption of ecological water use in certain region. The Cu and Mu of the Hai River was significantly lower than that of the Yellow River, which indicates that ecological construction in the Hai River needs to be intensified. The Cu and Mu is the highest in mountainous area, which shows that the level of ecological construction is higher in this area but the development leeway is small. The Cu is relatively higher in Shanxi Linfen, Jingcheng, Lvliang and Taiyuan districts, which shows that the vegetation area in Lvliang and Taiyuan is much larger, the coverage rate is lower, but ecological water for vegetation is little. While the Mu is the highest in Linfen and Jingcheng, which indicates that the coverage rate is much higher, but the potential of ecological water for vegetation is low.(4)The sustainable assessment of ecological water use shows that the ecological water use are in a coordinated or quasi-coordinated state for Changzhi, Jingcheng, Xinzhou, Linfen, Yuncheng cities, i.e. a quasi-coordinated state for Jinzhong city, and low coordinated state for Taiyuan, Yangquan, Shuozhou, Datong and Lvliang cities.(5) Through studies on the ecological water use and water resources utilization in Shanxi province, this paper makes the following recommendations: on the one hand, ecological constructions in Shanxi should pay attention to the radical regulation and source control, filtration through sand, the flood-storage and discharge capacity, and runoff regulation, in order to reduce the impact on the amount of water resource, enhance the transformation of invalid evaporation through the forest-grass measures. On the other hand, with measures of references, intercept, storage, the province should further stabilize and improve water resources development and utilization of water resources, strengthening agriculture, industry, domestic water-saving efforts to control water pollution, improve reclaimed water use efficiency, so as to achieve rational allocation of water resources.(6) The key issue of ecological water use research is to further strengthen the study on ecological water use of forest and the interaction and influence of ecological water use and water resources.