On 4 September 2026, the average daily discharge of the Rhine at Basel-Kleinhüningen was 444 m³/s, with a daily minimum of 334 m³/s and a daily maximum of 525 m³/s. This average was lower than 1% of all measured daily discharges since 2020, indicating exceptionally low flow conditions. The maximum discharge on that day ranked 19th over the last 30 days, 2nd among all September days since 2020, and also 2nd among all days since 2020, confirming that even the daily peak was unusually low by historical standards.

Over the past 30 days, the highest discharge was 817 m³/s on 22 August 2026, while the lowest was 319 m³/s on 8 August 2026. The current flow is therefore close to the lowest levels recorded in the last month. Table 2 lists the months with the lowest flow conditions since 2020; September 2026 appears among them with a minimum average flow of 444 m³/s, and the current daily average is already at that monthly minimum level.

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.