SPATIOTEMPORAL PATTERNS OF FLOW IN MONTANE NON-PERENNIAL STREAMS

Intermittent and ephemeral streams in dryland environments are important for supporting both aquatic and terrestrial biodiversity because they provide water to vegetation, food and shelter for wildlife and act as cool and moist refugia in arid landscapes. Understanding when and where water flows provides insights into the availability of water, its response to external controlling factors, and potential sensitivity to climate change and human activities. Knowledge of the timing of drying/wetting cycles can also be useful to map critical habitats for threatened and endangered species that rely on these temporary water sources. However, identifying locations and monitoring the timing of streamflow and channel sediment moisture is challenging given its high temporal and spatial variability. In this paper, we analyzed daily conductivity from 37 sensors distributed along 10 streams across a mountain front in Arizona (United States) to assess spatiotemporal patterns in flow permanence, defined as the timing and extent of water in streams. Conductivity sensors provide information on surface flow and sediment moisture, supporting a stream classification based on seasonal flow dynamics. This classification provides information on flow responses to seasonal rainfall, highlighting stream reaches very reactive to rainfall versus those demonstrating more stable streamflow. A qualitative interpretation shows that underlying geology affects the strength of stream responses to input rainfall. In summary, conductivity data can be used to map potential habitat for water-dependent species, while also supporting analysis of potential sensitivity of dryland streams and the habitats they support to ongoing climate change.