七里海潟湖近百年水体交换能力变化特征

Characteristics of Water Exchange Capacity Changes in Qilihai Lagoon in the Recent Hundred Years

摘要:

基于三重嵌套的非结构网格建立七里海潟湖水动力和物质输运模型，采用实测资料对模型的潮位、流速和流向进行验证，结合卫星遥感影像资料，模拟1950—2018年七里海潟湖地貌演变过程，利用水体冲刷时间尺度探究不同工况下潟湖水体交换能力的变化特征。结果表明，自然条件下，径流改变较海平面变化对水体交换能力的影响更为显著；挡潮闸的开闭是影响潟湖水体交换能力的关键因素，同时潟湖围垦降低了纳潮量也减弱了水体交换能力，但降低幅度较小；潮汐通道工程的变化是影响水体交换能力的主要原因，潮汐通道由弯曲变为顺直及其拓宽均增强了潟湖的水体交换能力。

Abstract:

In this paper， MIKE21 is used to establish a two-dimensional hydrodynamic and mass transport model based on the triple nested non-structured grid and the measured data are used to verify the tide level， the current speed， and the current direction. In combination with the satellite remote sensing image data， the evolution of Qilihai Lagoon from 1950 to 2018 is simulated. The water flushing time scale is used to investigate the changing characteristics of water exchange capacity under different conditions and the results show that under natural conditions， the runoff change is more significant on water exchange capacity compared with water level changes. The opening of the tidal sluice is a key factor affecting the water exchange capacity of the lagoon. The reclamation project reduces the tide prism， but the slight reduction has a little impact on the water exchange capacity. The construction change of tidal inlet is the main factor affecting the water exchange capacity. The change of tidal inlet from bending to straight and its widening enhance the water exchange capacity of the lagoon.