Rhine flow at Basel hits near-record low for August

August 6, 2026

On 5 August 2026, the Rhine's discharge at Basel was exceptionally low, ranking below 1% of all daily flows since 2020 and making August 2026 the second-lowest August on record. Such low water levels sharply increase transport costs, degrade water quality, and impose cooling and supply restrictions on industries and communities along the river.

On 5 August 2026, the average daily discharge of the Rhine at Basel-Kleinhüningen was lower than 1 % of all daily discharges recorded since 2020. The flow ranged from a minimum of 386 m³/s to a maximum of 592 m³/s, with a mean of 453 m³/s. These values are not notably high; the maximum discharge ranked only 14th over the last 30 days, 10th among all August days since 2020, and far from the top in the full record since 2020.

Over the past 30 days, the highest discharge was 710 m³/s on 19 July 2026, and the lowest was 321 m³/s on 2 August 2026. Table 2 lists the months with the lowest flow conditions since 2020, and the current month of August 2026 already appears as the second-lowest on record, with a minimum average daily flow of 442 m³/s, only slightly above the record-low August 2022 value of 436 m³/s.


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.



Table 1: Comparison of Rhine River Discharge from 2026-08-05 and historic August statistics
metric '2026-08-05'::date Historic
Average discharge 453.2 1039.0
Maximum discharge 591.7 2834.5
Minimum discharge 385.5 259.9


Table 2: The five months since 2020 with the lowest daily flow
Month Min Avg Flow [m3/s]
08.2022 435.9
08.2026 441.5
07.2026 442.1
04.2025 470.4
03.2023 471.4

Figure 1: Rhine River Discharge [m³/s] over the Past 30 Days

Data source: Rhein Wasserstand, Pegel und Abfluss
Additional resources: Data provider: Federal Office for then Environment (FOEN), Hydrological Data and Forcasts

🤖 This text was generated with the assistance of AI. All quantitative statements are derived directly from the dataset listed under Data Source.