附着性藻类生长-迁移模型及其在南水北调中线工程中的应用

A growth-migration model of periphyton and its application in the middle route of the South-to-North Water Transfer Project

附着性藻类广泛存在于自然水体中,有很强的生命力且能通过释放孢子/配子等多种方式进行繁殖与迁移。传统附着藻类生长模型往往仅考虑了藻类生长过程及水动力影响,但藻类的繁殖迁移过程也是附着藻类生活史的重要部分。通过在传统附着藻类生长模型中引入繁殖迁移过程,构建了适用于附着性藻类的生长-迁移模型,并通过相关实验结果进行了率定验证。针对南水北调中线工程中藻类增殖问题的定性研究表明:当干渠内水流流速小于0.4 m/s时,附着藻类容易大量增殖,故附着性藻类容易聚集在水渠弯道处及两侧边壁。通过增大总干渠输水流量可提高渠内水流平均流速,从而控制渠内附着藻类平均生长密度,当干渠流量为350 m^(3)/s时,干渠中附着藻类平均密度仅为流量为180 m^(3)/s时的20%。模拟结果符合南水北调中线工程中附着藻类的实际分布规律,研究成果可为南水北调中线工程中附着性藻类增殖问题的进一步治理提供参考。

Periphyton are widely found in natural water bodies.They have strong vitality and can reproduce and migrate by releasing spores/gametes.Conventional growth models of periphyton usually only involves the algal growth process and the influence of hydrodynamics,lacking the consideration of the reproduction and migration process,which is also an integral part of the life cycle of periphyton.In this paper,a growth-migration model suitable for periphyton was constructed by introducing the reproduction and migration process into the conventional growth model,which was then calibrated and verified using relevant experimental results.According to the qualitative research of algal proliferation issues in the middle route of the South-to-North Water Transfer Project,periphyton could proliferate abnormally when the discharge velocity was lower than 0.4 m/s and thus gathered at the cannel corners or side walls.Increasing the water discharge of the main canal could effectively increase the average flow velocity and reduce the growth of periphyton.The average density of the periphyton in the main canal when the flow velocity was 350 m^(3)/s only accounted for 20% of that when the flow velocity was 180 m^(3)/s.The simulation results are consistent with the actual situation,and this research can provide some reference for the further treatment of periphyton proliferation in the middle route of the South-to-North Water Transfer Project.