• 关键词：感潮河段  溶解氧  数值模拟  拉格朗日粒子示踪  调控策略

• 基金项目：国家自然科学基金（No.42006138）；中央级公益性科研院所基本科研业务专项（No.PM-zx703-202002-042， PM-zx703-202004-140）

• 陈仲晗
• 生态环境部华南环境科学研究所，广州 510655

• 徐娟
• 生态环境部华南环境科学研究所，广州 510655

• 刘帅帅
• 生态环境部华南环境科学研究所，广州 510655

• 綦世斌
• 生态环境部华南环境科学研究所，广州 510655

• 赵庄明
• 生态环境部华南环境科学研究所，广州 510655

• 摘要：城市感潮河段受径流、潮汐动力及流域排污等多重影响，易引发河道缺氧现象.通过建立潭江（开平段）二维水动力水质模型，并采用拉格朗日粒子示踪、情景分析等手段，研究水流输运、生化反应过程对溶解氧的影响，进而探索提升关键断面溶解氧浓度的调控策略.结果表明：①潭江干流上游水团输送比支流镇海水更快，且同等增量下，潭江干流流量变化对下游影响更大；但对潭江干流开平市区下游新美断面污染贡献中，镇海水对其总磷（TP）污染贡献较大，而新昌水对其总氮（TN）污染贡献较大；②新美断面、镇海水的娄冈断面及新昌水的公义断面均为耗氧断面；水体有机物耗氧是本区域溶解氧消耗的主要过程，占总消耗的64.4%，其次为底泥耗氧，占总消耗的32.5%；水体中氧气的主要来源为浮游植物的光合作用，占比约64.6%；③增加上游流量、下移城区排口位置或削减上游临近城区污染源均可提高下游溶解氧浓度；与镇海水相比，提高潭江干流流量的效果更为明显；下移城区排口位置虽有效果但可操作性较弱.

• Abstract：Urban tidal rivers are prone to hypoxia problems due to the influence of complex hydrological conditions and urbanization. A two-dimensional model MIKE 21 with Particle-Tracking and ECO Lab functions was built to study the influence of hydrodynamic and biochemical processes on dissolved oxygen （DO） dynamics in the Tanjiang River （Kaiping reach） and to further assess the efficiency of different management solutions for oxygenation using a scenario analysis. The results show that：①the transport time is faster from the mainstream than from the Zhenhai branch and has a much more significant influence from the discharge. The main source of phosphorus in the Xinmei section is the Zhenhai branch， while the main source of nitrogen is the Xinchang branch. ②Net DO consumption is positive in the Xinmei， Lougang and Gongyi sections. During the simulation period， oxygen consumption mainly occurred through the mineralization of organic matter in the water column （64.4%） and in the sediment （32.5%）. The amount of oxygen originating from primary productivity accounts for 64.6%. ③The increase of river flow， reductions in urban sewage overflows， and the displacement of urban discharge downstream from the Xinmei section can improve DO levels in the Xinmei section but with variable efficiency. High river flows from the mainstream area can increase the DO concentration more efficiently than those from the Zhenhai branch. The downstream relocation of wastewater discharge from the city of Kaiping allows for better oxygenation levels despite the low feasibility of this strategy.

• Key words：tidal river  dissolved oxygen  numerical simulation  Lagrange particle tracking  control strategy

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