Abstract:
Tidal asymmetry is an important factor affecting sediment net transport and riverbed evolution in tidal estuary. In this paper, aiming at the Yongjiang River in Ningbo, Zhejiang, a two-dimensional tidal wave mathematical model including Fenghua River, Yao River, Yong River and corresponding offshore area was established to simulate the tide in Yongjiang River. Model validation was conducted by using monthly measured tide level data at nine tidal stations, and the results showed that this model could accurately replicate the tide process and the distribution of tidal asymmetry in the three river channels. Through skewness analysis on the tidal level simulation it was found that the monthly average tidal asymmetry of the Yongjiang River was dominated by the flood tide, and the intensity was relatively large at the Yaojiang sluice and the Fenghua River, and the Yongjiang River was the smallest. There was a dominant area of about 4 to 6 km of ebb tide at the entrance of the Yongjiang River. The asymmetry was obvious in the intra-monthly high tide period, and the whole river reaches were dominated by high tide. The intensity of asymmetry in neap tide period was obviously less than that in spring tide period, and there was a dominant section of ebb tide over 10 km above the entrance of Yongjiang River