Measurement took place at the 'Olewiger Bach', a small low-mountain creek in Rhineland-Palatinate (Germany) from 2011 until 2017. Sediment pore water temperature was measured at 3 Profiles (Lance 1 to 3) with 7 depths below the sediment-water-interface (0.02 m, 0.05 m, 0.1 m, 0.15 m, 0.25 m, 0.45 m, 0.65 m) using temperature lances with a resolution of 0.032 °C and an accuracy of 0.1 °C (Umwelt- und Ingenieurtechnik GmbH Dresden). The lances are embeded in a riffle-pool-sequence. Lance 1 is situated at the first rise of the riffle, followed downstream after 7 m by Lance 2, and after 12 m by Lance 3 on the top of the riffle. The reference gradient was calculated by substracting the groundwater level from the surface water level. Groundwater level was measured in a groundwater observation well using an Eijkelkamp CTD + BaroDiver and corrected for a linear subsiding trend using linear regression. Surface water level was continiously measured 1 km downstream using a SEBAPLUS radar measurement system. Between regularly measured surface water levels next to the groundwater observation well and the continiously measured data at the radar station a linear regression was calculated to receive continious surface water levels at the study area.