IberWQ: new simulation tool for 2D water quality modelling in rivers and shallow estuaries

Abstract

This paper presents a new freeware simulation tool (IberWQ) for 2D water quality modelling in rivers and non-stratified estuaries. The model computes the spatial and temporal evolution of several species and variables which are relevant for the evaluation of the environmental status of rivers and estuaries, including: Escherichia coli, dissolved oxygen, carbonaceous biochemical oxygen demand, organic nitrogen, ammoniacal nitrogen, nitrate–nitrite nitrogen, water temperature and salinity. A depth-averaged transport equation is solved for each variable with a mass conservative unstructured finite volume solver. IberWQ is fully coupled to the hydrodynamic module of the software Iber, a freeware simulation tool for solving the 2D shallow water equations. Both models are integrated in the same windows graphical environment, including several tools which allow the user to generate unstructured meshes adapted to the site topography, define spatially variable input parameters and visualize model outputs. We present four application examples to illustrate the possibilities of the software for the dynamic simulation of water quality in rivers and estuaries.

Computational Modeling of Fine Sediment Relocation Within a Dam Reservoir by Means of Artificial Flood Generation in a Reservoir Cascade

“…In this work, no bedload has been considered. The suspended sediment transport was modeled by solving the depth averaged turbulent convection‐diffusion equation , using the method described in Cea et al (). Here C is the depth‐averaged concentration of suspended solids; U x and U y are the horizontal depth‐averaged velocity components; ν t is the turbulent viscosity; Г is the molecular diffusion coefficient for suspended solids; S c,t , is the Schmidt number, which relates the moment turbulent diffusion coefficient with the suspended turbulent diffusion coefficient; D is the deposition rate; and E is the entrainment rate.…”

“…The reader is referred to Bladé, Cea, & Corestein, Escolano, et al (2014) and the references therein for a detailed description and experimental validation of the numerical schemes used to solve the shallow water equations, which are not included in this paper for brevity. This hydraulic module has been applied to several studies in the past, including the river inundation modeling, overland flow (Cea & Bladé, 2015), evaluation of gully restoration measures (C. Castillo et al, 2014), wood transport in rivers (Ruiz-Villanueva et al, 2014), and water quality loss (Cea et al, 2016).…”

“…In this work, no bedload has been considered. The suspended sediment transport was modeled by solving the depth averaged turbulent convection-diffusion equation (1), using the method described in Cea et al (2016).…”

Two-Dimensional Dam-Break Flood Analysis in Data-Scarce Regions: The Case Study of Chipembe Dam, Mozambique

“…It is a freely distributed numerical model for simulating turbulent free surface unsteady flow. It has been successfully used for a wide range of applications, including modeling of river flow and quality [39][40][41], geomorphic impacts of dam failure [12], sedimentation and flushing in reservoirs [42] or check dam hydraulics [43]. For a detailed description of model equations and numerical methods, the reader is referred to [26] and the references therein.…”

Hydraulic model study of the intake-outlet of a pumped-storage hydropower plant

“…For a detailed description of the model, the reader is referred to Bladé et al (2014), Cea et al (2016) and the references therein. Iber is a free software which is available for download at www.iberaula.es.…”