Soil moisture dynamics of Muhly seeps in a hillslope hollow during low flow and storm conditions

Abstract

Groundwater seeps are important hydrological and ecological features of many landscapes. Research on hyperseasonal Muhly hillslope seeps, dominated by Seep Muhly grass (Muhlenbergia reverchonii), has been limited. Muhly seeps result from interbedded Cretaceous limestone and marl geology of the Fredericksburg and Washita Groups of the Grand Prairie Ecoregion and are found on middle to lower slopes, often with an associated barrens environment. Results indicate that geologically controlled Muhly seeps are hydrologically disconnected from the rest of the hillslope, with the wettest portions of the hillslope at the Muhly seeps. The mechanics of these systems present a departure from traditional VSA and saturated wedge hillslope theories. Due to the extent of comparable geology within the Grand Prairie, results from this study could apply across a sizeable area, representing a large-scale deviation from traditional hillslope hollow mechanisms.