思贤滘近期水文情势分析

该文根据近期实测水文资料对马口站和三水站河床演变、水位流量关系、分流比和过滘流量进行了分析。结果表明1989—2007年思贤滘水文情势变化明显:2 m以下河道过水面积,三水站2007年是1993年的2.1倍,马口站为1.5倍,三水站比马口站下切严重。河床下切导致年平均水位不断下降,在相同年平均流量下三水站1993年与2006年年平均水位相差近1 m。三水站和马口站河床下切的不平衡导致洪水期思贤滘过滘流量转变为西江流向北江,枯水期北江流向西江的流量减小,三水站分流比从而逐渐增大。2005年此后,随着采砂活动的有效控制,三水站和马口站河床较为稳定,2007—2014年思贤滘水文情势变化较小,无明显趋势性变化规律。

Study ofHydrological Characteristics in Sixianjiao Reach

In this paper, the tendency of riverbed evolution, stage discharge relation, split ratio, and the discharge in Makou and Sanshui hydrological stations are analyzed by measured hydrologic data. It shows that the hydrological regime changes obviously. With the same water level of 2m, the cross section area of Sanshui station in 2007 is 2.1 times than that in 1993, and the cross section of Makou station in 2007 is 1.5 times than that in 1993, the downcutting of riverbed in Sanshui station is more serious than that in Makou station. Due to the imbalance of riverbed downcutting, the annual average water levels fall down with the same annual average discharge. The annual average water in 2006 is approximately 1.0 m lower than that in 1993. The flow direction changes and it flows from the Xijiang River to Beijiang River during flood period. The flow rate decreases in the dry season. The flow diversion ratio of Sanshui station becomes larger. With the effective control of sand extraction after 2005, the riverbed becomes stable, and the hydrological regime changes little with no obvious law of tendency.