Laboratory Validation of an Integrated Surface Water— Groundwater Model

Abstract

The hydrodynamic surface water model DIVAST has been extended to include horizontally adjacent groundwater flows. This extended model is known as DIVAST-SG (Depth Integrated Velocities and Solute Transport with Surface Water and Groundwater). After development and analytical verification the model was tested against a novel laboratory set-up using open cell foam (60 pores per inch-ppi) as an idealised porous media representing a riverbank. The Hyder Hydraulics Laboratory at Cardiff University has a large tidal basin that was adapted to simulate a surface water-groundwater scenario using this foam, and used to validate the DIVAST-SG model. The properties of the laboratory set-up were measured and values were determined for hydraulic conductivity (permeability) and porosity, evaluated as 0.002 m/s and 75% respectively. Lessons learnt in this initial experimentation were used to modify the flume construction and improve the experimental procedure, with further experimentation being undertaken of both water level variations and tracer movement. Valuable data have been obtained from the laboratory experiments, allowing the validity of the numerical model to be assessed. Modifications to the input file to include representations of the joints between the foam blocks allowed a good fit between the observed and modelled water levels. Encouraging correlation was observed in tracer experiments using Rhodamine-WT dye between the observed exit points of the tracer from the foam, and the modelled exit points with time.

Hydrodynamic Effects of Tidal-Stream Power Extraction for Varying Turbine Operating Conditions

“…The DIVAST model was developed to simulate hydrodynamic, solute, and sediment transport processes in rivers, estuaries, and coastal waters as it incorporated a flooding and drying capability. DIVAST was originally developed by [35], and since then, it has been calibrated extensively, verified against laboratory and field data [36], and extended to investigate hydro-environmental engineering problems [37][38][39][40][41][42]. Meanwhile, the DIVAST-TVD model was introduced by [43], and it was developed to analyse scenarios that require modelling of rapidly varying flow conditions.…”

A Numerical Solution for the Integrated Analysis of Water Resources Management: Application to the Mero River Watershed, La Coruña, Spain

“…and Maxwell, R.M. [9], whose coupling approach is based on the continuity of the pressure head and fluxes at the ground surface; Jones, J.P. et al [10], whose coupling of Richards equation and various approximations of the Saint-Venant equation relies on the hypothesis of a first order diffusion of water between the surface and the subsurface and an interface layer with a finite thickness; Shan, H. et al [11], who integrated flow and transport in surface water, groundwater, and overland regimes; Spanoudaki, K. et al [12], whose 3-D integrated surface water-groundwater model behavior was verified; Weill, S. et al [13], who developed a model based on the generalization of Darcy-Richards equation that allowed implicit coupling between surface and subsurface; Sparks, T. et al [14], based on recent extensions, developments and verifications of DIVAST model, in order to more accurately describe the interactions between surface and groundwater flows; and García-Rábade, H. et al [15], who developed a new coupled finite element model for the joint resolution of the shallow water and the groundwater flow equations in order to solve problems related to surface and subsurface water flows.…”