Review of Simulation Models for Riverine Macrophytes Growth

Abstract Macrophytes are aquatic species considered true plants (bryophytes, pteridophytes, gymnosperms, and angiosperms), excluding algae and cyanobacteria (Dieterich et al., 2022) in this work. Their presence in rivers is often undesirable because large amounts of macrophyte biomass can cause ecosystem disruption, alter transportation, and affect recreational uses. On the other hand, macrophytes can provide substrate and wildlife habitat, influence carbon and nutrient cycles, and moderate currents and sediment dynamics. This study is focused on growth models of freshwater macrophytes in riverine systems. A literature review was performed using primarily Google Scholar and the Google Search engine. The search was subsequently extended following references in articles and those suggested by journal algorithms to technical notes and reports from government agencies and academic theses. Models of macrophyte dynamics were the focal point for adaptation on future scenarios. These models were compared based on their input and output data. Finally, the study points out research gaps and suggests key areas for future investigation, including parameters to be included in potential models. One hundred studies were identified initially, then scrutinized and narrowed down to 31 publications under consideration. The majority of models focused on lakes and reservoir systems; however, a few were designed for river systems. Models can be divided into several subroutines as the complexity of the study requires but the main three are chemical, biological and physical parameters. These were tabulated to obtain the number of publications evaluating each parameter. The aim of this process was to evaluate the factors used in aquatic vegetation modeling. The physical compartment included 19 elements, the biological aspect incorporated 15 elements, and the chemical compartment integrated 11 factors. The output of these models was summarized and showed the hydraulic roughness or hydrodynamic roughness as the major factor present in eleven references. This output generally indicated that the river flow was impacted by the river bed, erosion and deposition processes. These studies showed particular attention to the water level and flow effects on macrophyte growth. The impact of vegetation in flow distribution, erosion, sediment movement, and river dynamics is highlighted in the literature. However, the effects of macrophytes and nutrients on water quality keeps the attention of researchers on this topic. One of the identified gaps in the literature is the impact or influence of macrophytes in the creation of river sections modulating sedimentation processes, that was initially proposed by Kang et al. (2018) applying braiding indexes.