Estimating groundwater-ephemeral stream exchange in hyper-arid environments: Field experiments and numerical simulations

摘要

Highlights?Physical clogging leads to a reduction in streambed hydraulic conductivity.?Temperature is the main factor affecting river losses during cold season.?Temperature profiles allow estimation of seasonal variations in river losses.AbstractSurface water infiltration from ephemeral dryland streams is particularly important in hyporheic exchange and biogeochemical processes in arid and semi-arid regions. However, streamflow transmission losses can vary significantly, partly due to spatiotemporal variations in streambed permeability. To extend our understanding of changes in streambed hydraulic properties, field investigations of streambed hydraulic conductivity were conducted in an ephemeral dryland stream in north-western China during high and low streamflow periods. Additionally, streamflow transmission losses were numerically estimated using combined stream and groundwater hydraulic head data and stream and streambed temperature data. An analysis of slug test data at two different river flow stages (one tes