Impact of a lowered water table on water holding capacity of high elevation meadow soils

Meadow degradation, as a product of overgrazing or disruption of hydrologic regime, is a critical problem facing a variety of environments, including high elevation ecosystems of the Sierra Nevada, California and has become a focus of major research and restoration efforts. Within the historic range of water level in a meadow, it is hypothesized that a meadow will retain its water holding capacity and resiliency. However, if the water table drops below a historic level, due to climate change and/or management practices, the process of soil consolidation will influence the resiliency of the meadow through the irreversible plastic deformation of the soil pores. The subsequent change in soil structure results in decreased porosity, increased bulk density, and a reduction in permeability of the meadow. Such changes can adversely impact the overall water holding capacity of the meadow. This study utilizes a modified triaxial system combined with a multiphysics modeling approach to quantify the historic limit of dryness experienced in a high elevation meadow and degree of consolidation the meadow would experience if that limit was exceeded.