【作者】 袁辉；

【导师】 王里奥；

【作者基本信息】 重庆大学 ， 环境工程， 2006， 博士

【摘要】 三峡工程自开工建设以来,其引发的生态环境问题就一直为世人所关注。建成后的三峡水库将有600多km长,水域面积1 084km2,总库容达445.7亿m3,这将是中国未来最重要的水资源之一。工程自2003年6月正式蓄水以来,库区水位已抬升至139m。2006年,三峡水库水位将抬升至156m,到2009年水位将最终升至175m。由于三峡水库采取“蓄清排浊”的运行方案,这将使库区沿江地区形成最大水位落差为30m的消落带;同时,夏季底水位、冬季高水位的运行方式,也使这部分地区的水位涨落与自然状态下河流水位的消落季节相反。三峡重庆库区消落带分布于145m-175m之间,根据淹水时间不同,消落带上部区域170m-175m处于淹水时间较短,而下部区域145m-155m之间淹水时间最长。针对这一特点,本文根据这三种淹水状态,分别进行了实验室模拟淹水实验。实验表明消落带土壤处于淹水状态下,将向江水释放N、P营养物质,经淹水-落干处理后的土壤,其等温吸附曲线有所变化,表明土壤对N、P的最大量发生了变化,并且土壤释放N、P能力与其吸附外源N、P量多少相关。根据实验数据,本文从一级动力学方程出发,推出了在不同淹水状况下,消落带不同区域(上部、中部和下部区域)在淹水后,其N、P的释放速率方程。根据速率方程,进一步并分高、中、低三种水平预测三峡重庆库区消落带初次淹水后营养物质的释放量:高水平下TP释放量为1 484.2t/a,TN为5 479.2t/a,氨氮为3 832.9t/a;中水平下TP释放量为118.9t/a,TN为4 683.1t/a,氨氮为133.3t/a;低水平下TP释放量为14.4t/a,TN为2 802.6t/a,氨氮为50.4t/a.本文并进一步采用一维水质模型,对典型的开县消落带进行模型概化后,在高水平下,对水质量影响进行了模拟预测。预测结果表明消落带淹水后,在高水平条件下开县消落带土壤全淹后对水环境中TP、TN和氨氮浓度的贡献值虽较小,但是不能排除在水位逐步抬升过程中,淹没土壤对局部水域水质影响较大的可能性。三峡库区有大量的工农业人口和城镇,消落带形成后,除了峡谷地区的陡坡型消落带以外,坡度较缓地势开阔的消落带必然会受到人类工作的影响和干扰。通过对消落带的淹水实验分析可知,这部分消落带如果不采取适当的保护利用方式,将会成为库区新的污染源,从而增加库区水体发生富影响化的风险。本文在生态系统健康评价的理论基础上,分析了三峡重庆库区消落带可能的四种保护利用模式,即“直接利用开发模式”、“生态保护区建设模式”、“生态试验示范区建设模式”、“消落带护理模式”。并根据生态系统健康评价的原则和方法,建立健康评更多还原

【Abstract】 The ecological and environmental problems initiated by the Three Goreges Reservoir (TGR) Project are highly concerned since the project beguan. After the completetion of this Project, there will be a great artificial reservoir with more than 600 km long, a water surface area of 1 084 km2 and a capacity of 39.3 billion m3, which will also be important fresh water source for China in the near future. After the first water storage begun in June 2003, the water level has now raised to 139 m. And in 2006, the water level will raise to 156 m and to 175 m in the year 2009. Since the operation plan of this huge reservoir is to‘store clean water and disharege turbid water’, the water level will alternate between 145 m and 175 m forming a wet-dry zone. This water-level alternation is opposite to the nature alternation which is high water level in summer and low water level in winter.As the wet-dry zone in Chongqing Muncipality in the TGR Area located between 145m - 175m, based on different submerging time, the upper part (170m-175m) of the wet-dry zone is submerged much shorter than the bottom part (145m-155m). In view of this situation, three types of simulating submerging experiments were conducted to present the upper, middler and bottom parts of the wet-dry zone of the Reservoir area. The results of the experiments show that when the soil is inundated, the N and P in the soil will leach out gradually. The soil samples after wet-dry treatment have different isothermal adsorption curve which means the soil’s maximum N and P adsorption capability changes under different condictions. The results also demonstrate that the quantity of N/P pollutants vary with the extraneous sources affected the soil samples.Based on the experiments data and derivated from the first order kinetics model, different leaching models of N/P under different inundated condiction were constructed to predict different parts of the wet-dry zone of the TGR area. Three pollutant leaching risk levels were given in this paper to project the quantity of N/P pollutants realsed from this zone during the first dam operation period. The projections are: under high risk level the TP, TN and NH3-N released from this zone are 1 484 2 t/a, 5 479.2 t/a and 3832.9 t/a repectively; under middler risk level, the TP, TN and NH3-N quantities released are 118.9 t/a, 4 683.1 t/a and 133.3 t/a repectively; and under the low risk level, the TP, TN and NH3-N quantities released are 14.4 t/a, 2802.6 t/a and 50.4 t/a respectively.更多还原