The Effects of Gabion Construction on Infiltration in Ephemeral Streams – Presentation on October 7th, 9:30am in Cady Hall, Patagonia Library
Borderlands Restoration invites Chloe Fandel, M.S. in Hydrology, to present the results of her study on the effects gabions have on infiltration in ephemeral streams.
‘Low-tech rock structures called gabions are commonly used in dryland stream channels to reduce erosion, slow floodwaters, and increase infiltration. Gabions may also increase water availability for riparian vegetation, and increase the duration of surface flow in ephemeral stream channels. However, their effects on infiltration and recharge are not well-understood. This study tested low-cost methods for easily quantifying the total infiltration induced by gabion construction in an ephemeral stream channel, over the course of a single flow event. We used well-established methods to find point infiltration fluxes from subsurface temperature time-series. Unique to this study, we then upscaled these measurements to the gabion’s entire area of influence using time-lapse photo data, which recorded the onset of flow and the duration of ponding. For a flow lasting ~5 hours, we estimated that a single gabion increased the infiltration volume by 60 to 380% immediately upstream of the structure, and that five gabions over a 1.5 km length of channel increaced the infiltration volume by 2 to 13%. We also found the photo data to be invaluable in obtaining these estimates, and in understanding the dynamics of a remote field site.’