Daily discharge data Lobith (1901-2024) and Cologne (1817-2024)

(This text comes from the paper this dataset is connected to) <br>Discharge estimates for Lobith are based on flow velocity measurements and estimates of the cross section at the specific location. Prior to 1932, flow velocity was measured using a floating stick (Kraijenhoff floater, also known as a Cabeo rod). From 1932 to 1935, a floating chain composed of connected wooden blocks was used, operating on a similar principle. Both methods were employed between 1936 and 1943. No flow velocity measurements were conducted between 1944 and 1946 due to the Second World War and its immediate aftermath. From 1946 to 1999, flow velocity was measured using Ott current meters, and since 2000 an acoustic Doppler current profiler (ADCP) has been used.<br>For Lobith, flow velocity measurements are used to establish rating curves (so-called $Q$--$h$ relationships), which relate water level (usually measured through stilling wells) to discharge. Since 1977, these rating curves have been updated regularly to account for temporal changes in channel conditions, including channel bed incision. In 2008, a so called $Q$--$f$ relationship was derived, which has additionally accounted for hysteresis between discharge and water level associated with the rising and falling limbs of flood waves. This relation has been in use by the Dutch water management authority retroactively since 2003.<br>Daily water level data and corresponding discharge estimates at Lobith are available from 1 January 1901 to 23 October 1996. Hourly data are available from 24 October 1996 to 31 December 2012, and 10-minute data from 1 January 2013 onward. From 1901 to 1988, daily values correspond to fixed-time observations at 08:00 CET, whereas from 1989 to 23 October 1996 they represent 24-h averaged values. Our analysis is based on daily discharge and therefore uses fixed-time observations prior to 1989 and daily-averaged values thereafter.<br>Discharge data for Cologne cover the period from 1817 to 2024 and are available on a daily basis (rounded to multiples of tens).