Comparison between backward probability and particle tracking methods for the delineation of well head protection areas

In this work, a deterministic and a probabilistic method for the delineation of well head protection areas are applied and compared. The deterministic method was implemented using the automatic backward particle tracking algorithm (APA, Tosco et al., Water Resour Res, 44(7):W07419, 2008). The backward probability model rests upon the backward adjoint-based model developed by Neupauer and Wilson, and allows the inclusion of dispersion in the definition of capture zones. The two methods are evaluated comparing the "advective front" of the probability protection area and the perimeter given by the particle tracking method. Furthermore, a semi-quantitative study was performed over probability protection areas, in order to evaluate the influence of dispersivity on the extent and growth rate of capture zones identified by fixed probability isolines

Advances in High-Performance Computing: Multigrid Methods for Partial Differential Equations and its Applications

The program package UG provides a software platform for discretizing and solving partial differential equations. It supports high level numerical methods for unstructured grids on massively parallel computers. Various applications of complex up to real-world problems have been realized, like Navier-Stokes problems with turbulence modeling, combustion problems, two-phase flow, density driven flow and multi-component transport in porous media. Here we report on new developments for a parallel algebraic multigrid solver and applications to an eigenvalue solver, to flow in porous media and to a simulation of Navier-Stokes equations with turbulence modeling

On the effective hydraulic conductivity and macrodispersivity for density-dependent groundwater flow

In this paper, semi-analytical expressions of the effective hydraulic conductivity ( KE) and macrodispersivity ( αE) for 3D steady-state density-dependent groundwater flow are derived using a stationary spectral method. Based on the derived expressions, we present the dependence of KE and αE on the density of fluid under different dispersivity and spatial correlation scale of hydraulic conductivity. The results show that the horizontal KE and αE are not affected by density-induced flow. However, due to gravitational instability of the fluid induced by density contrasts, both vertical KE and αE are found to be reduced slightly when the density factor ( γ ) is less than 0.01, whereas significant decreases occur when γ exceeds 0.01. Of note, the variation of KE and αE is more significant when local dispersivity is small and the correlation scale of hydraulic conductivity is large