A nullah or nala (
Hindustani
Hindustani may refer to:
* something of, from, or related to Hindustan (another name of India)
* Hindustani language, an Indo-Aryan language, whose two official norms are Hindi and Urdu
* Fiji Hindi, a variety of Eastern Hindi spoken in Fiji, and ...
or "nallah" in
Punjabi
Punjabi, or Panjabi, most often refers to:
* Something of, from, or related to Punjab, a region in India and Pakistan
* Punjabi language
* Punjabi people
* Punjabi dialects and languages
Punjabi may also refer to:
* Punjabi (horse), a British Th ...
) is an 'arm of the sea',
stream
A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a 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.
In the drier parts of
India and
Pakistan, and in many parts of
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, 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 deep and 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
Stormwater, also spelled storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil ( infiltrate) and become groundwater, be stored on depressed la ...
and can exacerbate
floods.
Canal
In
East Asia, a nullah () refers to an open, usually concrete-lined
channel
Channel, channels, channeling, etc., may refer to:
Geography
* Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water.
Australia
* Channel Country, region of outback Austral ...
designed to allow rapid
drainage of stormwater or
industrial wastewater from high ground, to prevent flooding or
stagnation in urbanised coastal areas,
[ ] and basically is an often dry
canal used as a reserve drain. One such example is the
Kai Tak Nullah in
Hong Kong.
References
;Attribution
*{{1911, wstitle=Nullah
Valleys
Hindi words and phrases
Geography of India
Indian English idioms
Water in India
Urdu-language words and phrases