考虑海水入侵影响的漳卫新河河口生态基流研究

Assessment on ecological baseflow in Zhangweixin River estuary considering saltwater intrusion

本文分别采用水文学法和生境模拟法对漳卫新河河口区域生态基流进行估算,并基于MIKE21 FM建立了该区域海水入侵模型,对辛集挡潮闸不同下泄流量时原始河道和清淤后河道的海水入侵进行模拟研究,以论证所估算生态基流的合理性。结果显示:大口河至cs21断面为潮流主导段,沿程平均盐度基本不受下泄流量影响;cs21断面至辛集闸为潮流-下泄流量共同作用段与下泄流量主导段。随着辛集闸下泄流量从4 m3/s增加至8 m3/s,下泄流量主导段向下游延伸5 km;下泄流量增大至12 m^3/s时,各主导段范围不变,因此建议辛集闸下泄生态基流为8 m3/s。本文介绍了一种生态基流的估算方法,以期为河口区域生态基流的确定提供技术支撑。

In this study,a hydrological method and habitat simulation method are adopted to estimate the ecological baseflow in the Zhangweixin River estuary.And based on MIKE21 FM,a salinity intrusion model is developed for this estuary to simulate saltwater intrusion to its original riverway and dredged riverway under the condition of different discharges by the Xinji sluice and to verify the estimation of its ecological baseflow.The result shows that the section from the Dakou River outlet to CS21 is a tidal flow dominant area that features the cross-sectional average of salinity and its streamwise variation both nearly independent of the sluice discharge.The section from CS21 to the sluice is dominated by the sluice discharge but controlled by the joint action of the sluice and the tidal flow.As the sluice discharge increases from 4 m^3/s to 8 m^3/s,the sluice dominant section extends 5 km further downstream,while a further increase in the sluice discharge up to 12 m^3/s leads to nearly no more extension.Thus,we suggest that the ecological baseflow at the sluice should be 8 m^3/s.