Fig 1.
Study streams, watersheds and distribution of sensors on the field along the Soultzbach (West watershed) and the Trautbach (East).
All tributaries in the study area are ephemeral and were not active during field study. Impoundments are labeled by their order of stream appearance (Table 1); they are located upstream A, between A and B, between E and F, between H and I.
Table 1.
Impoundment features.
Table 2.
Location of temperature monitoring stations on each stream.
Table 3.
Daily mean, minimum, maximum, and standard deviation of stream temperature.
Fig 2.
Surface water temperature time series during the study.
Green: Soultzbach stream. Blue: Trautbach stream. Letters indicate monitoring stations (see Fig 1).
Fig 3.
Thermal amplitude (daily maximum temperature—daily minimum temperature) along Soultzbach (a) and Trautbach (b) streams.
Letters indicate monitoring stations. Red line: maximum thermal amplitude across the study period. Green line: minimum thermal amplitude across the study period. Blue line: mean thermal amplitude across the study period.
Fig 4.
Temperature time series in the stream and adjacent hyporheos.
Upper-left quadrant: B station. Upper-right quadrant: C station. Lower-left quadrant: E station. Lower-right quadrant: I station. Blue line: stream temperature. Brown lines: hyporheos temperature at increasing depths, from 10cm-deep (pale brown) to 20cm-, 30cm- and 40cm-deep (dark brown).
Table 4.
Lag time (in h) between surface water and hyporheos maximum temperature at different depths.
Fig 5.
Boxplot of mean hourly temperature along the seasons (from June to December), along the stream (from B to I site) and with depth (blue: Surface water temperature; shades of brown: Hyporheos water temperature).
Table 5.
Mean monthly temperature difference with depth.