【作者】 刘梅冰；

【导师】 陈兴伟；

【作者基本信息】 福建师范大学 ， 自然地理学， 2006， 硕士

【摘要】 闽江下游河道属感潮河段，受径流和潮流的双重影响，河流流态复杂；省会福州依江而立，人类活动频繁，水环境问题比较严重，开展闽江下游河道水动力、水质问题研究，具有重要的理论与现实意义。 对闽江下游河道水环境存在的主要问题及原因进行了分析。大量生活污水、畜禽养殖和工业废水直接或间接排入闽江，部分河道水体功能互相矛盾，水污染压力大；下游河道的过量采砂及水口电站的蓄水拦沙导致河床下切严重，由此引发闽江口咸潮上溯，已经并将进一步影响福州地区的饮用水安全。 根据描述河道非恒定流运动的Saint-Venant方程，以及污染物浓度变化的一维对流扩散方程，采用Preissmann四点偏心隐式差分格式，建立了闽江下游河道(竹岐——梅花)一维水动力、水质模型，运用实测资料率定了糙率、纵向离散系数和污染物降解系数，验证了模型的合理性。应用该模型，1)对枯水条件下闽江下游河道水流运动特性进行了模拟，并就河道采砂对水流动力条件的影响进行了定量评价；2)充分考虑了下边界潮汐类型和浓度变化、上边界来水量及污染负荷、河段内排污口设置和排放条件等各种边界条件，对该河段污染物运动的时空规律进行了比较系统、全面的模拟研究，对感潮河道汊道之间污染物的相互影响进行了详细分析。更多还原

【Abstract】 The lower reaches of Minjiang River is tidal channel network. Fuzhou city, the capital of Fujian Province, stands on the side of the river. Due to the human activities, water environmental problems are serious and the research of hydrodynamic and water quality modeling for the lower reaches of Minjiang River has theoretic and practical significance.Through investigating and appraising the current situation of hydrologic and water environment in the lower reaches of Minjiang River, the thesis makes the conclusions that a great deal of sewage drained into the river without standard disposal have bought water pollution, which is more serious in some reaches where the regionalizations of water environment function are contradictory. Excessive sand extraction and construction of Shuikou hydropower station give rise to the descending of the riverbed and even the saltwater intrusion which occurs frequently in the dry season.Based on the Saint-Venant equations describing the movement of unsteady flow and one-dimension convection diffusion equation describing the variation of contaminant concentration, using the Preissmann weighted implicit four-point scheme, one dimensional hydrodynamic and water quality models are established and applied to the lower reaches of Minjiang River. According to the simultaneous observed data, main parameters are calibrated. The results of the computation prove that the models are rational and reliable. Applying the verified models, the characteristics of low flow are numerically simulated, and the effect of excessive sand extraction is quantificationally evaluated. Comprehensive simulation and research on the contaminant concentration in the tidal river have been conducted with representative boundary conditions, including the variation of lower boundary(Minjiang River mouth) tidal types and contaminant concentration, upper boundary(Zhuqi hydrologic station) discharges and total pollution load, sewage outfalls setting and so on.更多还原