One-Way Flow System Water Quality Modelling of Terantang Reclamation Channel

Abstract

The implementation of reclamation process in wetland has encountered some obstacles, such as the occurrence of pyrite oxidation, sedimentation, and accumulation of toxic materials, especially the concentration of Fe (iron) in the channel. The condition of the reclamation channel which is influenced by tidal events and environmental factors causes the dynamics of Fe concentration to be strongly influenced by hydrodynamic aspects and its interaction with dissolved and suspended particulates. An accurate model will be useful as a tool to evaluate alternative management of water systems to overcome the problem of Fe concentration accumulation in the tidal wetland reclamation channel. Fe fate and transport were modeled using a numerical model of hydrodynamics and water quality EFDC (Environmental Fluid Dynamic Code). The partition process separates the metal fraction into two phases (dissolved and solid), which is related to the value of the partition coefficient (Kp). The application of the partition process is considered to have a significant influence on the accuracy of the estimated Fe concentration. The simulation results of the model with the partition coefficient approach have better accuracy than the conventional model which tends to be overpredicted compared to the observation data. Simulation of one-way flow system shows a decrease of Fe concentration in the channel by an average of 52.9% compared to two-ways flow system. The application of one-way flow system is possible through the placement of flap gates that will direct the flow to the drainage channels.