A muddy flood is produced by an accumulation of run-off over agricultural land. Sediments are picked up by the run-off and carried as suspended matter or bed-load. Muddy floods are typically a hill-slope process, and should not be confused with mudflows produced by mass movements.
Muddy floods can damage the road infrastructure and may deposit layers of mud blanket and may also clog sewers and damage private property.
It has been referred to 'muddy floods' since the 1980s. A similar designation appeared in French ('inondations boueuses') during the same period.
Muddy flood generation
Muddy runoff is generated on agricultural land when the soil surface is exposed or sparsely covered by vegetation. Large quantities of run-off usually generated by heavy storms is needed to start such a flood.
Muddy flood occurrence
Muddy floods have been observed in the entire European
loess belt. Other affected areas include
Normandy
Normandy (; french: link=no, Normandie ; nrf, Normaundie, Nouormandie ; from Old French , plural of ''Normant'', originally from the word for "northman" in several Scandinavian languages) is a geographical and cultural region in Northwestern ...
and
Picardy
Picardy (; Picard and french: Picardie, , ) is a historical territory and a former administrative region of France. Since 1 January 2016, it has been part of the new region of Hauts-de-France. It is located in the northern part of France.
His ...
(
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
), central
Belgium
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to the ...
and southern
Limburg, the
Netherlands
)
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.
Muddy floods have also been observed in
Slovakia
Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to th ...
and
Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populou ...
.
Temporal evolution
An increase in muddy flood frequency has been observed during the last twenty years (e.g. in central Belgium,). This increase in their frequency may be due to a number of factors including:
* Change in agricultural practices that leave field bare of crops in the autumn and winter
* A shift to crops that are more sensitive to soil erosion;
* land consolidation (enlargement of fields, removal of landscape buffer elements such as hedges.
* construction of new houses, upstream of cropland increasing run-off volumes and intensity
* increased frequency of heavy rainfall.
Control measures
Preventive measures consist in limiting runoff generation and sediment production at the source. Alternative farming practices (e.g. reduced tillage) to increase runoff infiltration and limit erosion in their fields may assist.
Curative measures generally consist in installing retention ponds at the boundary between cropland and inhabited areas.
An alternative is to apply other measures than can be referred to as intermediate measures. Grass buffer strips along or within fields, a
grassed waterway (in the thalwegs of dry valleys) or earthen dams are good examples of this type of measures. They act as a buffer within landscape, retaining runoff temporarily and trapping sediments.
[Evrard, O., Vandaele, K., van Wesemael, B., Bielders, C.L, 2008. A grassed waterway and earthen dams to control muddy floods from a cultivated catchment of the Belgian loess belt. Geomorphology 100, 419-428.]
Implementation of these measures is best coordinated at the catchment scale.
See also
*
November 2010 European Windstorms
References
{{reflist
Flood