Oral Presentation Freshwater Sciences 2023

Water-level recession characteristics in isolated pools within intermittent streams (#254)

Songyan Yu 1 , Ryan Burrows 2 , Margaret Shanafield 3 , Mark Kennard 1
  1. Griffith University, Nathan, QLD, Australia
  2. School of Ecosystem and Forest Sciences, The University of Melbourne, Richmond, VIC, Australia
  3. College of Science and Engineering, Flinders University, Bedford Park, SA, Australia

Persistent surface water pools within intermittent streams provide critical refuges for freshwater species by facilitating their survival during extended dry periods. However, our understanding of how pool water levels recede is limited, hindering our ability to quantify and predict aquatic refuge persistence. We characterise variations in water-level recession rates based on one year of water-level measurements in five intermittent streams. We found that water level recedes at a constant rate after streamflow ceases in our study streams, a rate often significantly higher than that during low-flow periods. However, water-level recession rates varied considerably among cease-to-flow periods within pools in the same intermittent stream and between nearby streams. The constancy of water-level recession during a cease-to-flow period is applicable to other intermittent streams, but a detailed understanding of the factors influencing recession rates is needed for predicting recession rates for ungauged streams and identifying persistent aquatic refuges across river networks.