(Redirected from Drainage pattern)In
geomorphology, a 'drainage system' is the pattern formed by the streams,
rivers, and
lakes in a particular
watershed. They are governed by the topography of the land, whether a particular region is dominated by hard or soft rocks, and the gradient of the land.
A 'drainage system' (agriculture) is an intervention to control
waterlogging aiming at soil improvement for agricultural production
A 'drainage system' (industrial and residential) is a facility to dispose of liquid waste.
Types of drainage system (geomorphology)
Drainage systems fall into one of several categories, depending on the topography and geology of the land:
Dendritic drainage system
Dendritic drainage systems are the most common form of drainage system. The term dendritic comes from the
Greek word "dendron", meaning tree, due to the resemblance of the system to a tree. In a dendritic system there is one main river (like the trunk of a tree), which is joined and formed by many smaller
tributary rivers. Dendritic systems form in
V-shaped valleys; as a result, the rock types must be impervious and non-porous.
Parallel drainage system
A parallel drainage system is a pattern of rivers caused by steep slopes with some
relief. Because of the steep slopes, the streams are swift and straight, with very few tributaries, and all flow in the same direction. This system forms on uniformly sloping surfaces, for example, rivers flowing
southeast from the
Aberdare Mountains in
Kenya.
Trellis drainage system
Trellis systems form in areas of alternating geology, particularly chalk and clay. The main river (the consequent) flows straight down hill. Subsequent streams develop perpendicular to the consequent along softer rock and erode it away, forming vales. The consequent river then cuts through the escarpments of harder rock. Obsequent streams flow down the
dip slope of the escarpments to join the subsequent streams. The
River Ain with its tributaries is an example, whilst in Southern England the
North Downs and the
South Downs have dry valleys in a trellised pattern due to erosion after the ice age.

Radial drainage pattern around Mt Taranaki, New Zealand.
Rectangular drainage system
This develops on a strongly jointed rocky terrain.
Radial drainage system
Rivers radiate outwards from a central point, e.g. a volcanic cone or from a mountain range
batholith
Deranged drainage system
A deranged drainage system is a drainage system in
watersheds where there is no coherent pattern to the rivers and lakes. It happens in areas where there has been much geological disruption. The classic example is the
Canadian Shield. During the last
ice age, the topsoil was scraped off, leaving mostly bare rock. The melting of the glaciers left land with many irregularities of elevation, and a great deal of water to collect in the low points, explaining the large number of lakes which are found in Canada. The watersheds are young and are still "sorting themselves out". Eventually the system will stabilize.
Agricultural drainage system
In
www.waterlog.info on the FAQs page, item 3, one can find a paper on types of agricultural land drainage systems used in different parts of the world.
See also
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Subsurface drainage systems
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Watertable control
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Well drainage system
See also
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Drainage basin
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Sustainable urban drainage systems
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Sewage
External links
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ICS 91.140.80 Drainage systems - A series of the ISO standards