On 30 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 about 364 m³/s, with a minimum of 262 m³/s and a maximum of 435 m³/s. These values are exceptionally low: the maximum discharge on 30 September ranked 30th over the last 30 days, meaning it was the lowest daily maximum in that period. Compared with all October days since 2020, the maximum flow ranked 2nd lowest out of 210 measured days, and relative to all days since 2020 it was also among the very lowest on record for this station.

Over the past 30 days, the highest daily discharge was 618 m³/s on 31 August 2026, while the lowest was 188 m³/s on 22 September 2026. The current flow is therefore well below the recent monthly high and close to the lowest values observed in the last month. Table 2 lists the months with the lowest flow conditions since 2020; September 2026 appears as the lowest entry, with a minimum average flow of 361 m³/s. The current daily mean of 364 m³/s is essentially at that record-low monthly level, confirming that the Rhine at Basel is experiencing one of its most severe low-flow episodes in the available 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.