南水北调中线水源地丹江口水库水化学特征研究

丹江口水库是南水北凋中线工程的水源地,对水库中的5个点位进行了3 a的动态监测.对水化学类型和水化学特征进行了系统分析,运用相关分析及方差分析,对水化学时间、空间分布特征进行了研究.结果表明,TDS介于149.9-291.2mg·L-1,属于弱矿化度水.总硬度(以Ca2 、Mg2 浓度和计)介于40～50 mg·L-1之间,属于极软水.HCO3-及Ca2 分别介于122.5-170.0 mg·L-1、37.1-43.2 mg·L-1,分别占主要阴、阳离子组成的77.54%～77.87%和70.66%-77.93%.按照O.A.阿列金分类法,丹江口库区水质为HCO3--Ca型水.主要离子呈现一致的空间变化,在丹江库区沿水流方向逐渐降低,至汉江库区达到最小值.水化学特征的季节及时间变化表明,主要离子的浓度在枯季比在雨季大.丹江口水库水化学特征主要由岩石风化决定,高浓度的HCO3-及Ca2 主要来源于方解石和白云岩,但是上游及库区周边人为活动对NO3-产生了一定的影响.最后,提出了流域水资源保护的建议和措施.

Hydro-chemical Characteristics in the Danjiangkou Reservoir (Water Source Area of the Middle Route of the South to North Water Transfer Project), China

TDS, pH and major ions in the Danjiangkou Reservoir, the water source area of the Middle Route of the South to North Water Transfer Project of China were monitored during the period of 2004-2006 to systemically analyze hydro-chemical characteristics and water chemistry type. Analysis of variance (ANOVA) and correlation analysis were performed to explore their spatio-temporal pattern. The results show that the water is of low mineralized degree with a total dissolved solid ranging from 149.9-291.2 mg x L(-1), and soft water with a total hardness ranging from 40-50 mg x L(-1) x HCO3- accounts for 77.54%-77.87% of the total major anions with a content of 122.5-170.0 mg x L(-1), while Ca2+ accounts for 70.66%-77.93% of the total major cations with a content of 37.1-43.2 mg x L(-1), and the water is of a HCO3- -Ca type. Major ions show similar spatial variations, decreasing downstream in the Danjiang Reservoir, and reaching the lowest values in the Hanjiang Reservoir. The temporal and seasonal variations of the hydro-chemical characteristics show that the concentrations of major ions in the dry season are larger than those in the wet season. Hydro-chemical characteristics in the reservoir are mainly determined by the rock weatherization, while and anthropogenic activities in the upper-stream and the reservoir region have been influencing the NO3- concentration. Finally, conservation strategies of water resource in the reservoir and its upper stream are discussed.