鄱阳湖水龄季节性变化特征

摘要

基于环境水动力学模型EFDC源程序,建立了染色剂模型和水龄模型,在将模型与航测水文数据验证吻合的基础上,分别计算了鄱阳湖自然条件下春、夏、秋、冬季的水龄和倒灌前后鄱阳湖染色剂和水龄分布的变化,以及五河水系各分支河流水龄.分季节的水龄计算表明鄱阳湖水体交换受季节性来水影响明显.夏、秋季的水龄相对较小,在多数年份又受到长江水倒灌的影响导致水龄有所增大;冬、春季水龄较大,亦无长江水倒灌现象,相较于夏、秋季,水域面积明显减少.分支流的水龄计算表明,西南湖区的水体交换主要受到赣江的影响,西北湖区水体交换主要受到修水和赣江的影响,南部湖区主要受到抚河与信江的影响,东部湖区主要受到饶河的影响,湖心区和入江水道则受到五河水系的综合影响.同时水龄的研究表明拟建的鄱阳湖水利枢纽工程“调枯不调洪”的原则是合理的,为鄱阳湖水利枢纽工程论证提供了重要的参考依据.%Based on source code of Environmental Fluid Dynamics Model (EFDC),the water age model and conservative dye model were set up to study water age of seasons and individual rivers of Lake Poyang under natural conditions.Water age calculations indicate that seasonal variations of water age in Lake Poyang are significant.The water age of summer or autumn is smaller,which is increased during reversing process in flood season in most of consecutive years.The water age of winter or spring is larger without occurrence of reversing process.The water age of individual river in five river systems indicates that the exchange of water in the southwest lake zone is mainly influenced by Ganjiang River,whereas in the northwest zone influenced by Ganjiang River and Xinjiang River,in the southern lake zone by Ganjiang River and Xinjiang River,in the eastern lake zone by Raohe River,respectively.The central zone and channel to Yangtze River are influenced by the five rivers together.The proposed Lake Poyang Complex will be rational with principles "water level control during dry seasons not during flood seasons",and the model is proved of reference value for feasibility study of Lake Poyang Complex.