三峡工程蓄水后宜昌站水流特性变化及测验措施

为了探究三峡工程蓄水后水文站水流特性,以宜昌站为例,利用蓄水后多年实测资料,分析宜昌站水位特性和洪水特性。结果表明:水位波动性增强,同流量级下水位降低,历年最高水位下降、最低水位抬高,中低水位持续时间增长;中低水位流量呈现日周期变化,年最小流量有增大趋势,并逐渐稳定在6 000 m³/s左右,年最大流量因三峡水库调蓄得到控制,峰顶持续时间变长,年内水量变化为枯期增加、汛期减少,中低水位-流量关系呈多条单一线变化趋势。因此,根据现有水流特性变化,需调整水位和流量资料收集方式,以满足整编需要。

Variation and Test Measures of Flow Characteristics atYichang Station after Impoundment of Three Gorges Project

In order to explore the flow characteristics of hydrological stations after reservoir impoundment of Three Gorges project,we took Yichang station as an example and analyzed the characteristics of water level and flood according to measured data from 2003 to 2014.Results showed that water level fluctuation intensified and water level decreased under the same discharge,the highest annual water level declined and the lowest water level raised.The duration of mid-low water level increased and its discharge varied in daily scale;Moreover,annual minimum discharge tended to increase and gradually kept stable at 6 000 m3/s.Since annual maximum discharge was under the control of regulation and impoundment of Three Gorges reservoir,the duration of flood peak lasted longer and annual discharge varied with longer low flow period and shorter flood period.Relationship between mid-low water level and discharge showed a tendency of many single lines.Therefore,according to current characteristics of water flow,we should adjust the methods of collecting water level and discharge data to meet the need of compilation.