基于水动力水质模拟的感潮河网生态补水研究

Research on ecological water replenishment of tidal river network based on hydrodynamic and water quality simulation

为探究改善粤港澳大湾区河口城市水系水动力不足、水质较差的情况,以东莞市滨海湾新区为例,进行以潮汐为水源的生态补水效果研究,考虑引潮河涌宽度、河涌连通的差异性拟定补水方案,建立研究范围内的水动力水质耦合模型,结合实测的同步水文水质数据对模型进行率定,模拟不同方案下引潮量、水位、流速、污染物特征值的变化趋势。结果表明:引潮河涌宽度增加,引潮量增大,但对河涌水位、流速等基本无影响,对水质提升效果影响也较小;河涌全部连通,有助于降低污染物特征值;断头涌内水流往复流动,污染物浓度较高;单纯通过引潮难以将NH_(3)-N浓度降低至Ⅴ类水标准限值以下,需辅以其他污染物削减措施。

In order to explore and improve the situation of insufficient hydrodynamics and poor water quality in estuarine urban river in Guangdong-Hong Kong-Macao Greater Bay Area,taking Binhaiwan Bay Area&Dongguan Port as an example,the effect of tidal water on ecological replenishment was studied.The differences between the width of tidal bore and the channel connectivity were considered,and the coupling model of hydrodynamics and water quality in the study area was established according to the synchronous measured hydro-water quality data.The variation trend of tidal volume,water level,velocity and pollutant characteristic value under different water supplement schemes was simulated and analyzed.The results show that with the increase of channel width,the tidal volume increase,but the water level,the velocity and the water quality are little affected.Interconnected rivers help to reduce the characteristic value of pollutants.The flow in truncated river become reciprocating flow,and the concentration of pollutants is higher.It is difficult to keep the NH_(3)-N under fifth class water quality through tidal flow alone,other pollutant reduction measures need to be supplemented.