Rhine at Basel hits record-low August flow since 2020.

August 17, 2026

On 16 August 2026, the Rhine at Basel-Kleinhüningen recorded exceptionally low discharge, with the daily mean of 424 m³/s ranking among the lowest values since 2020 and August 2026 currently holding the lowest minimum average flow on record. These low water levels have wide-ranging consequences, including higher shipping costs, degraded water quality, restrictions on cooling water use, and pressure on water supply, irrigation, and groundwater.

On 16 August 2026, the average daily discharge of the Rhine at Basel-Kleinhüningen was lower than 1% of all measured daily discharges since 2020. The daily mean was 424 m³/s, with a minimum of 358 m³/s and a maximum of 475 m³/s. These values are exceptionally low for the time of year. The maximum discharge on 16 August 2026 ranked 29th over the last 30 days, 3rd among all August days since 2020, and was also among the very lowest when compared with all days since 2020.

Over the past 30 days, the highest discharge was 710 m³/s on 19 July 2026, while the lowest was 319 m³/s on 8 August 2026. Table 2 lists the months with the lowest flow conditions since 2020. August 2026 currently has the lowest minimum average flow in the record, at 413 m³/s, followed by August 2022 at 436 m³/s and July 2026 at 442 m³/s. The current flow is therefore not only low for the season but also lower than any previously recorded monthly minimum since 2020.


Low water levels on the Rhine have consequences that reach well beyond the river itself. Cargo vessels have to reduce their load to stay clear of the riverbed, so more trips are needed to move the same volume and transport costs rise sharply, with the effect passed on to industries that depend on the waterway for coal, oil products, chemicals and grain. The shallower water also heats up faster in summer. Warmer water encourages bacterial growth, which can produce noticeable odors, and it holds less dissolved oxygen. The combination of higher temperatures, lower oxygen and more concentrated pollutants degrades water quality and can lead to fish kills. Swimming is generally discouraged under these conditions because of the higher bacterial load. Further effects include restrictions on power plants and industrial sites that draw river water for cooling, since they may no longer discharge warmed water without exceeding temperature limits, reduced dilution of treated wastewater, pressure on water supply and irrigation in the surrounding area, and falling groundwater levels along the river that affect riparian vegetation and wells.



Table 1: Comparison of Rhine River Discharge from 2026-08-16 and historic August statistics
metric '2026-08-16'::date Historic
Average discharge 423.7 1005.6
Maximum discharge 474.7 2834.5
Minimum discharge 358.4 259.9


Table 2: The five months since 2020 with the lowest daily flow
Month Min Avg Flow [m3/s]
08.2026 413.0
08.2022 435.9
07.2026 442.1
04.2025 470.4
03.2023 471.4

Figure 1: Rhine River Discharge [m³/s] over the Past 30 Days

Data source: Rhein Wasserstand, Pegel und Abfluss
Additional resources: Data provider: Federal Office for then Environment (FOEN), Hydrological Data and Forcasts

🤖 This text was generated with the assistance of AI. All quantitative statements are derived directly from the dataset listed under Data Source.