On 12 September 2026, the average daily discharge of the Rhine at Basel-Kleinhüningen was lower than 1% of all measured daily discharges since 2020. The daily minimum was 357 m³/s, the maximum was 536 m³/s, and the mean was 446 m³/s. These values are not notably high; on the contrary, they are exceptionally low for the available record since 2020. The maximum discharge on 12 September 2026 ranked 20th over the last 30 days, 8th among all September days since 2020, and was among the lowest values recorded for any day since 2020.

Over the past 30 days, the highest discharge was 817 m³/s on 22 August 2026, while the lowest was 291 m³/s on 8 September 2026. Table 2 lists the months with the lowest flow conditions since 2020, including August 2026, September 2026, August 2022, July 2026, and April 2025. The current flow is included in this table, confirming that the Rhine at Basel is experiencing one of its most pronounced low-flow periods in the recent record.

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.