On 22 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 mean was 375 m³/s, with a minimum of 188 m³/s and a maximum of 523 m³/s. These values are exceptionally low: the maximum discharge ranked 18th over the last 30 days, 14th among all October days since 2020, and among all days since 2020 it was also in the lowest range, consistent with the average being below the first percentile.

Over the past 30 days, the highest discharge was 749 m³/s on 28 August 2026, while the lowest was 228 m³/s on 21 September 2026. The current flow is therefore close to the lowest level of the last month. Table 2 lists the months with the lowest flow conditions since 2020; September 2026, with a minimum average flow of 375 m³/s, is the lowest on record in that table, followed by August 2026 at 413 m³/s and August 2022 at 436 m³/s. The present conditions are even more extreme than those previously recorded low-flow months.

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.