感潮河段城市湿地水动力模拟及改善方案研究

Study on hydrodynamic simulation and improvement scheme of urban wetlands in tidal reaches

湿地具有固碳释氧、涵养水源等作用,改善水体交换能力是湿地研究热点之一,但关于潮汐变动水位条件下湿地水体调控措施的探究相对较少。以长江南京段绿水湾湿地为例,建立平面二维水动力模型,开展感潮河段城市湿地水动力模拟及改善方案研究。计算不同水文条件及闸泵调度方案下湿地流场,分析潮位变动对绿水湾湿地水动力的影响,分析不同闸泵调度措施对水体流动性的改善效果。研究表明,闸泵联合调度可使枯季大部分区域水动力明显增强,但仍存在主槽外坑塘等局部滞水区,需通过湿地植被重构的方式提高水体自净能力。对易暴发藻类的4—5月,闸泵联合调度可较好改善绿水湾内上游区域的水动力条件,对于改善效果并不明显的下游区域建议增设补水点,降低水体富营养化风险。本研究可为绿水湾湿地的设计、建设与管理提供科学依据。

Wetlands play crucial roles in carbon sequestration,oxygen release,and water conservation.Enhancing water exchange capacity is a key focus in wetland research.However,there is a relative scarcity of studies on wetland water regulation measures under varying tidal water levels.To address this gap,a two-dimensional hydrodynamic model was developed,using the Lvshuiwan Wetland in the Nanjing section of the Yangtze River as a case study.The model was employed to simulate and propose improvement strategies for urban wetlands in tidal areas.The study involved calculating the wetland flow patterns under different hydrological conditions and sluice pump scheduling schemes.It also examined the impact of tidal level changes on the hydrodynamics of Lvshuiwan Wetland,and evaluated the effectiveness of different sluice pump scheduling measures on water flow.The findings indicate that combined sluice-pump operations can significantly enhance the hydrodynamic forces in most areas during the dry season.However,certain stagnant areas,such as pits outside the main trough,require improvement in the selfpurification capacity of the water through wetland vegetation reconstruction.During the months of April and May,characterized by frequent algae outbreaks,the combined operation of sluice pumps can improve the hydrodynamic conditions in the upstream area of Lvshuiwan Wetland.In the downstream area,where the improvement effect is not as pronounced,it is advisable to introduce water refill points to mitigate the risk of water eutrophication.This study provides a scientific foundation for the design,construction,and management of Lvshuiwan Wetland.