[A-HW21] Surface and subsurface hydrologic models: Technical advances and applications for water management

[AHW21-P03] Novel analytical model for multispecies transport of sequentially decaying reaction products in rivers influenced by stagnant water zones

*Jui-Sheng Chen¹, Ching-Ping Liang², Yo-Chieh Ho¹, Zhong-Yi Liao¹ (1.National Central University, 2.Fooyin University)

Keywords:River, Stagnant Water Zone, Transient Storage Model, Multispeices Transport, Analytical Model, Sequentially Dedaying Reaction Product

In rivers there are continuous exchanges of water and dissolved chemicals with their surrounding stagnant water zones. There has been increasing interest in understanding the dynamics and processes controlling solute transport in rivers influenced by their stagnant water zones for the protection of public drinking water intakes. Analytical models are widely used to obtain a better understanding and make accurate predictions of the transport and fate of contaminants in rivers. One common analytical approach for contaminant transport in rivers affected by stagnant water zone is the transient storage model (TSM) in which the first-order reaction mass transfer between the main river channel and stagnant water zones is assumed. Analytical solutions for the TSM have been reported for single contaminant in the literature. Some contaminants including chlorinated solvents, radionuclides and nitrogens can transform to sequentially generate daughter products. Analytical models for TSM for multiple species are required for more accurately predicting the movement behavior of both the original contaminant and its daughter compound in rivers. This study aims to develop novel analytical model for TSM for the purpose of investigating the transport of sequentially decaying reaction contaminants in rivers affected by stagnant water zones. It is found that the mass transfer coefficients between main river channel and the stagnant water zone plays a crucial role in controlling the multispecies transport in a river system.