black water estuary
1.Abstract: The Qiantang Estuary with violent hydrodynamic conditions is well known for its tidal bore.The regulation of the estuary in the past,especially the progress since the founding of new China are reviewed.The principles of the regulation and planning of the Qiantang Estuary formulated in 1960s are expounded,i.e.,to narrow the river to reduce the tidal prism,and to increase the ratio of the river flow to tidal discharge.The experience of estuary regulation/reclamation is summarized,especially the engineering measures to protect the groin head and to use polder dykes as sea defense works.Finally,the effect is analyzed of the large-scale constraction/reclamation in the estuary on the tides,flooding high water level,estuary bed and the northern deep waterway in the Hangzhou Bay.
