7 Numerical Modeling in Peat and Peatlands

As with many branches of environmental science, numerical modeling has been used to simulate peatland processes, with varying degrees of success. Simulating water table position (and sometimes soil moisture) is a common objective because water table (and soil moisture) is so important to peatland function from hydrological, water quality and solute transport, climate, biogeochemical, and ecological points of view. Those focusing on ecology, biogeochemistry, and sometimes climate often use a simplified approach to hydrology to drive mechanistic processes relevant to their primary interest. Here, we focus only on modeling groundwater (including soil-water) hydrology and transport. For the most part, modeling of flow and transport in peat and peatlands have used numerical models developed for the porous matrix of mineral systems.

The fundamental processes represented are mostly similar, but some features of peat and peatlands provide additional challenges that increase uncertainty. These include the very low hydraulic gradients associated with the relatively flat landscape, highly and sometimes systematically irregular surface (i.e., microtopography), highly compressible matrix, heterogeneity of hydraulic properties, and the dual porosity character of peat. This section focuses on the use of models to simulate flow and transport in peat and peatlands, and the special challenges of using such models.