THE CHARACTERISTICS OF STORM SURGE IN THE YELLOW RIVER DELTA AND THE DESIGN HEIGHT OF THE TIDAL BARRIER

- According to the statistics of the number and heights of tidal floods occurring in the Yellow River Delta, the northeast gale changed from southeast wind is the main cause of tidal floods in the Yellow River Delta, high waters of both tidal floods of the Yellow River Delta in 1964 and 1969 occurred when the wind setup of Bohai Sea was succeeded by decreasing water level in the north and increasing in the south. The increased water of Bohai Sea concentrated in Laizhou Bay and thus caused the enormous tidal floods. The tidal wave system with the tidal-free point of M2 tide as center in the Yellow River mouth causes 6-hour tidal time difference in the neighborhood of Shenxian Gou. The astronomical spring tides of the south and the west region occur alternately. The tidal -flood caused by the same increased amount of water is distinctly different between the two sides of Shenxian Gou. When the flood occurs in the west side, the south is in safety and vice versa. According to the estimated return period of spring high tide which occurs once in 200 years, a proposal concerning the design of the tidal barrier is that the crest elevation of the barrier originally designed to be 6 m above the average sea level of the Yellow Sea could be decreased to 4.5 meters in the west section, 4 meters in the middle and 5 meters in the south section. Thus the construction cost can be decreased while ensuring safety.