Because the mouth is impacted by the Changjiang 4km backwater withstand pressure,it often occures section flow direction turbulence,and the test points flow velocity direction back and forth phenomena of the vertical line in the high floodwater level period,therefore cause normal flow measurement trouble and great hydrometry errors.
由于受下游约4 km长江回水顶托影响,在高水位期经常出现断面流向紊乱、同垂线测点流向顺逆不定现象,给常规流量测验工作带来不便且引起较大的流量测验误差。