Pervasive changes in stream intermittency across the United States

Abstract Non-perennial streams are widespread, critical to ecosystems and society, the subject of ongoing policy debate. Prior large-scale research on stream intermittency has been based long-term averages, generally using annually aggregated data characterize a highly variable process. As result, it is not well understood if, how, or why hydrology non-perennial changing. Here, we investigate trends drivers three signatures that describe duration, timing, dry-down period across continental United States (CONUS). Half gages exhibited significant trend through time in at least one signatures, changes no-flow duration were most pervasive (41% gages). Changes substantial for many streams, 7% annual exceeding 100 days during study period. Distinct regional patterns change evident, with widespread drying southern CONUS wetting northern CONUS. These correlated aridity, though spatiotemporal variability diverse signatures. While timing strongly related climate, was watershed land use physiography. Our results indicate conditions increasing prevalence over much binary classifications ‘perennial’ ‘non-perennial’ an accurate reflection this change. Water management should reflect changing nature both today future.