page_title: Wiese (river)
section_title: Hydrology
hierarchical_section_title: Wiese (river) / Hydrology
caption_attribution_description: Monatsmittel Wasserabfluss der Wiese bei Kleinhüningen 1993-2007
context_page_description: The Wiese is a river, 57.8 kilometres long, and a right-hand tributary of the Rhine in southwest Germany and northwest Switzerland.
  From its source in Baden-Württemberg in the Southern Black Forest on the mountain of the Feldberg, it flows for a short distance though the county of Breisgau-Hochschwarzwald and then mainly across Lörrach and through numerous settlements including the county town of Lörrach. After crossing the international border, the lower reaches of the river pass through the canton of Basel-Stadt, mainly through the city of Basle and through its district of Kleinbasel before emptying into the Upper Rhine.
  The valley of the Wiese, which drains a catchment of 455 square kilometres, is called the Wiesental or Wiese Valley; it is oriented roughly towards the south-west. Its largest tributary is the Little Wiese which approaches from the north. The right-hand Rhine tributary of the Wiese and the left-hand Rhine tributaries of the Birsig, which discharges into the Rhine at the Basle port of Schifflände, and the Mühlebach, which flows under the Dreirosen Bridge, are the three biggest Upper Rhine tributaries on Swiss soil.
context_section_description: The mean annual precipitation within the catchment varies between about 2,000 millimetres in the Feldberg area and 882 millimetres in Lörrach. The amount of precipitation decreases from west to east and from north to south. The greatest precipitation occurs mostly in the months November to January, and, in the Black Forest, mostly as snow.
  As a result of the river's low storage capacity in the catchment area in the upper reaches of the Wiese and the combination of sudden snow melts during the föhn and heavy rainfall, flooding used to occur regularly in the past causing great damage to the population, property and the countryside. The increasingly severe floods of the second half of the 19th century were put down by contemporary writers to the ruthless deforestation of woods in the Kleine and Grosse Wiese valleys and the desolate and worthless areas on the Feldberg and Belchen, which were clearly unable to retain the amount of water that they had been able to in the past.
  Viewed over the year, the Wiese discharges the most water around the Christmas season and from mid-March to mid-April, and the least amount of water in August.
  The average discharge rate in Kleinhüningen is 11.3 m³/s. The Swiss Federal Office for the Environment measured the highest discharge rate during the period from 1933 to 2006 as 342.5 m³/s in 1944. However, events of this magnitude can be expected only every 200 years.
caption: Average monthly water drainage of the Wiese near Kleinhüningen 1993-2007
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