| To understand subsurface mechanisms controlling flow permanence, we assessed how lateral, vertical, and longitudinal shallow subsurface flow paths control the expression of surface flow during low flow periods, including intermittency at Gibson Jack Creek, in Pocatello, Idaho, USA. Water-table measurements, hydraulic gradients, and hyporheic exchange were monitored throughout hydrograph recession in WY2018. Our findings indicate: 1) shallow subsurface flow paths are dominant controls on surface flow permanence and 2) deviations from the drainage-area discharge relationship may predict intermittent locations in a stream network. Our results suggest that accurate subsurface characterization is critical to understanding the drivers of expansion and contraction cycles in intermittent streams and their likely responses to changes in climate and land use.
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