Introduction

Multilayer cover systems are often placed over mine wastes to support the growth of native plant species. The cover system must be designed to provide sufficient water and nutrients for the vegetation while protecting the root zone from upwards migrating dissolved solutes originating in the underlying waste. The goal of the design is to minimize the total cover depth while ensuring that the vegetation can be properly supported. The land-climate-interaction boundary condition in SEEP/W is best suited for simulation of the water dynamics in these types of systems because it considers precipitation, snowmelt, evaporation, runoff, and root water uptake occurring below the ground surface.

The objective of this example is to illustrate the application of the land-climate interaction (LCI) boundary condition to simulate the measured hydraulic response in an engineered soil cover and underlying waste material subject to measured climate variability. The cover system overlies a portion of a large saline–sodic overburden dump at the Syncrude Mine site north of Fort McMurray, Alberta. Huang et al. (2015) explored the soil water dynamics of six different cover systems supporting various qualities of vegetation. The performance of only one of those six cover configuration is simulated as part of this example. The journal publication by Huang et al. (2015) forms the basis of much of the information presented in this example file.

A secondary objective of this example is to illustrate the graphs that are available in SEEP/W to assist with interpretation; namely the graphs that assist with closing the water balance, tracking volumes of water stored within the cover, and checking for convergence problems via the water balance error.