Spatial Variability In a Waste Rock Pile

One particularly interesting aspect of numerical modeling is accounting for spatial variability in an individual material property. In the numerical modeling of any subsurface model the aspect of spatial variability of material properties is often a concern.

In general, quantifying sources of uncertainty has always been challenging. The list of potential aspects of introducing uncertainty into a numerical model includes: laboratory uncertainty, uncertainty regarding the governing process in a numerical model, climatic uncertainty, and uncertainty related to the proper discretization of a numerical model.

Spatial variability is of particular concern in performing seepage modeling because there is often uncertainty regarding the ability to measure the hydraulic conductivity (both saturated and unsaturated) of the material at the site. It is possible that laboratory measurements of saturated hydraulic conductivity could be in error by up to two orders of magnitude. If samples are taken around a site, even in the same layer, the amount of variance in saturated hydraulic conductivity can be significant.