椒江入海水沙通量的变化规律

Variations in water and sediment fluxes in the Jiaojiang River

基于椒江流域沙段和柏枝岙水文站1958-2013年实测径流量和输沙率资料,采用水文学和数理统计等方法,分析椒江流域始丰溪和永安溪入海水沙通量变化特征及相互关系,并对气候和人类因素影响进行讨论。研究结果表明:始丰溪和永安溪的水沙通量具有明显的年际变化和年内变化,水通量变化相对稳定,沙通量变幅大于水通量,始丰溪变幅大于永安溪;椒江洪枯季流量悬殊,洪峰暴涨暴落,梅汛期和台汛期是主要输水时期,台汛期是主要输沙时期;始丰溪和永安溪水沙通量之间具有较好的峰谷对应关系;椒江流域径流变化主要受降雨量控制,而输沙量变化还受其它因素影响;受人类活动影响,始丰溪和永安溪的水沙关系发生多次改变,突变时间与人类活动吻合;里石门水库的建成和运行,对始丰溪径流起到了调节作用,水沙通量年内分配趋于均匀。

Hydrographic method and mathematical statistics were used in this study to analyze the time series of runoff and sediment discharge data obtained from the Shaduan and Baizhiao hydrological stations in the Jiao- jiang River during 1958 -2013. Variations in water fluxes and sediment fluxes of Shifeng Brook and Yong＇ an Brook, and their relationship, were examined in this study. Impacts of climate and human activities were further discussed. Remarkable inter-and intra-annual variations of water fluxes and sediment fluxes were observed. Re- suits show that the variability of flow discharge was relatively less than that of sediment flux. The amplitude of variation in water fluxes and sediment fluxes of Shifeng Brook was greater than those of Yong＇ an Brook. There was great disparity between the flow discharge and sediment flux in flood and dry seasons in Jiaojiang River, the flood rose and fell sharply, rainy season and typhoon season were main periods of water transportation, and typhoon season was the main period of sediment transportation. A peak-trough relationship between flow dis- charge and sediment flux was revealed by this study. Flow discharge was mainly controlled by natural precipita- tion, but sediment load was affected by other factors. Relationships between water fluxes and sediment fluxes in Shifeng Brook and Yong＇ an Brook changed after the influence of human activities,and the occurrence time of change points almost accords with man-made events. Construction of Lishimen reservoir played a significant role in regulating water fluxes in Yong＇ an Brook,leading to uniform trend of intra-annual distribution of water fluxes and sediment fluxes.