On 2026-09-25, 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 387 m³/s, with a minimum of 284 m³/s and a maximum of 451 m³/s. These values are exceptionally low: the maximum discharge ranked 31st over the last 30 days, the lowest of all October days since 2020, and the lowest of all days since 2020.

Over the past 30 days, the highest discharge was 749 m³/s on 2026-08-28, while the lowest was 188 m³/s on 2026-09-22. Table 2 lists the months with the lowest flow conditions since 2020; September 2026 has the lowest minimum average monthly flow at 373 m³/s, followed by August 2026 at 413 m³/s and August 2022 at 436 m³/s. The current daily mean of 387 m³/s is only slightly above the September 2026 monthly minimum and remains far below typical seasonal values.

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.