鉴江河口底泥盐度释放规律研究

Study on Sediment Salinity Release in Estuaries and Loughs

底泥盐度释放是河口水资源利用的主要限制因子。本文以鉴江为例,基于野外实测与室内实验,系统分析了鉴江河口底泥盐度及水体氯离子的分布特征;通过振荡、换水及静态等实验,定量研究了河口底泥盐度释放规律。结果表明:(1)潮泛河口底泥盐度主要受上溯潮水的影响,有较为明显的梯度性;(2)底泥盐度释放量在初期较大,随着换水周期的累加,则逐步降低;在同一换水周期,底泥盐度释放强度与其本底盐度浓度成正指数关系;(3)静态释放时间越长,上覆水盐度越大,静置30d,三组样品上覆水的浓度分别达2 626mg·L-1、932 mg·L-1、533 mg·L-1,远远超过用水水质的要求。

Release of sediment salinity is the main restrictive factor for the utilization of water resources in estuary area. This paper studied the distribution characteristics of sediment salinity and concentration of chlorine ion with Jianjiang River as the study case, based on the re- sults of field monitoring and indoor experiment. By vibration, water exchanging and static state experiment, a quantitative study was made the release of sediment salinity. The results show that （1） the sediment salinity has obvious grads under the impact of tide; （2） the release intensity of sediment salinity is greater at the initial stage, and it decreases with the increasing of water exchanging cycles; （3） the release intensity of sediment salinity is exponentially related to its background concentration under the same water exchanging cycle; （4） the concentration of salinity of cladding water increases with the increase of static state time,, and the concentration of the three samples separately reach 2626mg·L-1,932 mg·L-1 and 533 mg·L-1 after 30 days.