Nullah

For other uses, see Nullah (disambiguation).

A nullah or nala (Hindustani or "nallah" in Punjabi) is an 'arm of the sea', stream, or watercourse, a steep narrow valley. Like the wadi of the Arabs, the nullah is characteristic of mountainous or hilly country where there is little rainfall.

A nullah in Spiti, India

In the drier parts of India and Pakistan, and in many parts of Australia, there are small steep-sided valleys penetrating the hills, clothed with rough brushwood or small trees growing in the stony soil. During occasional heavy rains, torrents rush down the nullahs and quickly disappear. There is little local action upon the sides, while the bed is lowered, and consequently these valleys are narrow and steep. In cities on the Delhi plain in India, nullahs are concrete or brick-lined ditches about 3 metres (10 ft) deep and 6 metres (20 ft) wide, used to divert monsoon rain away from the cities.

Encroachment into nullahs is a significant problem in many South Asian cities, since it hampers the drainage of stormwater and can exacerbate floods.^[1][2][3]

Canal

In East Asia, a nullah (Chinese: 明渠; pinyin: míngqú; Wade–Giles: ming²-chʻü²; Jyutping: ming⁴ keoi⁴; lit. 'open ditch') refers to an open, usually concrete-lined flood control channel designed to allow rapid drainage of stormwater or a sewerage channel for industrial wastewater from high ground, to prevent flooding or stagnation in urbanised coastal areas,^[4] and basically is an often dry canal used as a reserve drain. One such example is the Kai Tak Nullah in Hong Kong.

References

1. "Outdated stormwater system and encroached nullahs increase risk of 'urban flooding' in Pune". The Indian Express. 15 October 2020. Retrieved 2020-10-30.
2. "'Encroachment of nalas led to flooding in Hyderabad'". Telangana Today. 19 October 2020. Retrieved 2020-10-30.
3. "Illegal constructions, Nala encroachments led to floods in Karimnagar". The Siasat Daily. 21 August 2020. Retrieved 2020-10-30.
4. Wordie, Jason (January 20, 2008). "FYI: Why do some Hong Kong street names seem to have no connection to the area they are in?". South China Morning Post. p. 10. Retrieved January 8, 2014. (subscription required)

 

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Attribution

•   This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Nullah". Encyclopædia Britannica (11th ed.). Cambridge University Press.