ditch

A well maintained ditch

Ditches at the Ouse Washes nature reserve.

Waterplants growing in a ditch near Germany, showing Sagittaria sagittifolia to the right.

A ditch is usually defined as a small to moderate depression created to channel water.

In Anglo-Saxon, the word dic already existed and was pronounced with a hard c in northern England and as ditch in the south. The origins of the word lie in digging a trench and forming the upcast soil into a bank alongside it. This practice has meant that the name dic was given to either the excavation or the bank, and evolved to both the words dike/dyke and ditch. Thus Offa's Dyke is a combined structure and Car Dyke is a trench, though it once had raised banks as well. In the midlands and north of England, and in the United States, a dike is what a ditch is in the south, a property boundary marker or small drainage channel. Where it carries a stream, it may be called a running dike as in Rippingale Running Dike, which leads water from the catchwater drain, Car Dyke, to the South Forty Foot Drain in Lincolnshire (TF1427). The Weir Dike is a soak dike in Bourne North Fen, near Twenty and alongside the River Glen.

A ditch can be used for drainage, to drain water from low lying areas, alongside roadways or fields, or to channel water from a more distant source for plant irrigation. A trench can be defined as a long narrow ditch. Ditches are commonly seen around farmland especially in areas that have required drainage, such as The Fens in eastern England and the Netherlands.

Roadside ditches can provide a hazard to motorists, especially in poor weather conditions. It is not an uncommon sight in some rural areas to see cars, motorbikes, or bicycles that have crashed into ditches, or to hear of such accidents.

Fortification

See also counterscarp

In military engineering and fortification, a distinction is made between a ditch and a trench. A ditch is an obstacle, designed to slow down or break up an attacking force, while a trench is cover, intended to provide protection to the defenders. In Medieval fortification, a ditch was often constructed in front of a defensive wall to hinder mining and escalade. When filled with water, such a defensive ditch is called a moat. Later star forts of Vauban and others comprised elaborate networks of ditches and parapets, carefully calculated so that the soil for the raised earthworks was provided, as nearly as possible, entirely by the excavations whilst also maximising defensive firepower. Today ditches are obsolescent as an anti-personnel obstacle, but are still often used as anti-vehicle obstacles (see also berm).

Sustainability of drainage ditches

Drainage ditches play major roles in agriculture throughout the world. Improper drainage systems accelerate water contamination, excessively desiccate soils during seasonal drought, and become a financial burden to maintain. Industrial earth-moving equipment facilitates maintenance of straight drainage trenches, but entrenchment results in increasing environmental and eventually profound economic costs over time.^[1]

Sustainable channel design can result in ditches that are largely self-maintaining due to natural geomorphological equilibrium. Slowed net siltation and erosion result in net reduction in sediment transport. Encouraging development of a natural stream sinuosity and a multi-terraced channel cross section appear to be key to maintain both peak ditch drainage capacity, and minimum net pollution and nutrient transport.^[2]

Flooding can be a major cause of recurring crop loss -- particularly in heavy soils-- and can severely disrupt urban economies as well. Subsurface drainage to ditches offers a way to remove excess water from agricultural fields, or vital urban spaces, without the erosion rates and pollution transport that results from direct surface runoff. However, excess drainage results in recurring drought induced crop yield losses and more severe urban heat or desiccation issues.

Controlled subsurface drainage from sensitive areas to vegetated drainage ditches makes possible a more optimal balance between water drainage and water retention needs. The initial investment, allows a community to draw down local water tables when and where necessary without exacerbating drought problems at other times.^[3]

References

See also

External links

• Barbagallo, Tricia (June 01, 2005). "Black Beach: The Mucklands of Canastota, New York" (PDF). http://www.archives.nysed.gov/apt/magazine/MagSummer05FeatureArticle_000.pdf. Retrieved on 2008-06-04. 

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