“Geography of Chennai”的意思、由来-开放百科全书

Chennai is located at {{Coord|13.04|N|80.17|E|}} on the southeast coast of India and in the northeast corner of Tamil Nadu

. It is located on a flat coastal plain known as the Eastern Coastal Plains. The city has an average elevation of {{convert|6|m|ft}}, its highest point being {{convert|60|m|ft|abbr=on}}.

Geology

The geology of Chennai comprises mostly clay, shale and sandstone.^[1] The city is classified into three regions based on geology, sandy areas, clayey areas and hard-rock areas. Sandy areas are found along the river banks and the coasts. Clayey regions cover most of the city. Hard rock areas are Guindy, Velachery, Adambakkam and a part of Saidapet.^[2] In sandy areas such as Tiruvanmiyur, Adyar, Kottivakkam, Santhome, George Town, Tondiarpet and the rest of coastal Chennai, rainwater run-off percolates very quickly. In clayey and hard rock areas, rainwater percolates slowly, but it is held by the soil for a longer time. The city's clayey areas include T. Nagar, West Mambalam, Anna Nagar, Perambur and Virugambakkam.{{fact|date=October 2018}}

Climate

The average annual rainfall is about {{convert|1400|mm|in|abbr=on}}. The city gets most of its seasonal rainfall from the north-east monsoon winds, from mid-September to mid-December. Cyclones in the Bay of Bengal sometimes hit the city. Highest annual rainfall recorded is 2,570 mm in 2005.^[5] The most prevailing winds in Chennai is the Southwesterly between the end of May to end of September and the Northeasterly during the rest of the year.

{{Weather box|width=auto

|location={{align|left|{{ed|:Geography of Chennai}}}} Chennai, India (1981–2010)
|metric first=Yes
|single line=Yes
|Jan record high C = 34.4
|Feb record high C = 36.7
|Mar record high C = 40.6
|Apr record high C = 42.8
|May record high C = 45.0
|Jun record high C = 43.3
|Jul record high C = 41.1
|Aug record high C = 40.0
|Sep record high C = 38.9
|Oct record high C = 39.4
|Nov record high C = 35.4
|Dec record high C = 33.0
|year record high C = 45.0
|Jan high C = 29.3
|Feb high C = 30.9
|Mar high C = 32.9
|Apr high C = 34.5
|May high C = 37.1
|Jun high C = 37.0
|Jul high C = 35.3
|Aug high C = 34.7
|Sep high C = 34.2
|Oct high C = 32.1
|Nov high C = 29.9
|Dec high C = 28.9
|year high C = 33.1
|Jan low C = 21.2
|Feb low C = 22.2
|Mar low C = 24.2
|Apr low C = 26.6
|May low C = 28.0
|Jun low C = 27.5
|Jul low C = 26.4
|Aug low C = 25.9
|Sep low C = 25.6
|Oct low C = 24.6
|Nov low C = 23.1
|Dec low C = 21.9
|year low C = 24.8
|Jan record low C = 13.9
|Feb record low C = 15.0
|Mar record low C = 16.7
|Apr record low C = 20.0
|May record low C = 21.1
|Jun record low C = 20.6
|Jul record low C = 21.0
|Aug record low C = 20.6
|Sep record low C = 20.6
|Oct record low C = 16.7
|Nov record low C = 15.0
|Dec record low C = 13.9
|year record low C = 13.9
|rain colour = green
|Jan rain mm = 25.9
|Feb rain mm = 3.4
|Mar rain mm = 3.5
|Apr rain mm = 14.4
|May rain mm = 34.2
|Jun rain mm = 55.8
|Jul rain mm = 103.8
|Aug rain mm = 126.8
|Sep rain mm = 147.7
|Oct rain mm = 315.6
|Nov rain mm = 374.4
|Dec rain mm = 177.4
|year rain mm = 1382.9
|Jan rain days = 1.4
|Feb rain days = 0.8
|Mar rain days = 0.3
|Apr rain days = 0.8
|May rain days = 1.8
|Jun rain days = 4.0
|Jul rain days = 6.5
|Aug rain days = 7.7
|Sep rain days = 7.3
|Oct rain days = 10.9
|Nov rain days = 11.5
|Dec rain days = 5.8
|year rain days = 58.8
|Jan humidity = 73
|Feb humidity = 72
|Mar humidity = 70
|Apr humidity = 69
|May humidity = 62
|Jun humidity = 57
|Jul humidity = 64
|Aug humidity = 66
|Sep humidity = 72
|Oct humidity = 77
|Nov humidity = 78
|Dec humidity = 77
|year humidity = 70
|Jan sun = 268.3
|Feb sun = 268.1
|Mar sun = 293.6
|Apr sun = 290.2
|May sun = 279.9
|Jun sun = 202.6
|Jul sun = 185.2
|Aug sun = 193.6
|Sep sun = 198.6
|Oct sun = 194.6
|Nov sun = 182.7
|Dec sun = 204.3
|year sun = 2761.7
|source 1 = India Meteorological Department (temperatures and precipitation)^[6]^[7]
|source 2 = NOAA (sunshine duration and humidity 1971–1990)^[8]

}}

Water bodies

Two rivers meander through Chennai, the Cooum River (or Koovam) in the central region and the Adyar River in the southern region. Both rivers are heavily polluted with effluents and trash from domestic and commercial sources. The Adyar, which is much less polluted than the Cooum, is de-silted and cleaned periodically by the state government. A protected estuary of the Adyar forms the natural habitat of several species of birds and animals. The Buckingham Canal, {{convert|4|km|mi|abbr=on}} inland, travels parallel to the coast, linking the two rivers. The Otteri Nullah, an east-west stream runs through north Chennai and meets the Buckingham Canal at Basin Bridge.^[9]Several lakes of varying size are located on the western fringes of the city. Red Hills, Sholavaram and Chembarambakkam Lake supply Chennai with potable water. Groundwater sources are mostly brackish.

Historically, Chennai has faced a problem of water supply shortages as no big river flows through it with a resulting over-reliance on annual monsoon rains to replenish water reservoirs. The city's ground water levels have been depleted to very low levels in many areas. Many residents buy their drinking water. An earlier Veeranam project was unsuccessful in solving the city's water supply shortages, but the New Veeranam project which became operational in September 2004 has greatly reduced dependency on distant sources.^[10] In recent years however, due to heavy and consistent monsoon rains and the implementation of rainwater harvesting (RWH) techniques by Chennai Metrowater at their Anna Nagar Rain Centre, water shortages have been reduced significantly, and this has led Chennai to be a model of RWH technology for other cities.^[11] Moreover, newer projects like the Telugu Ganga canal project that brings water from water-surplus rivers like the Krishna river in Andhra Pradesh have eased water supply shortages. The city is also constructing sea water desalination plants to further ease water supply shortages.

Layout

For administrative purposes Chennai is divided into five talukas; namely Egmore-Nungambakam, Fort Tondiarpet, Mambalam-Guindy, Mylapore-Triplicane and Perambur-Purasawalkkam.

The Chennai Metropolitan area consists of three districts namely Chennai city and the districts of Kanchipuram and Thiruvallur. The city area covers an area of {{convert|476|km2|sqmi|abbr=on}}.^[12] The metropolitan area covers 1,177 km² (455 mi²). The city is divided on the basis of composition into four major parts: North, Central, South and West.

North Chennai is primarily an industrial area. Central Chennai is the commercial heart of the city and the downtown area. South Chennai and West Chennai, previously predominantly residential areas are fast turning into commercial areas, hosting a large number of IT and financial companies. The city is fast expanding along the Old Mahabalipuram Road, GST Road, Sriperumbdur, Koyambedu and Ambattur.

The Chennai Metropolitan Development Authority has drafted a Second Master Plan for Chennai, that aims to develop a satellite townships around the city. Contiguous satellite towns include Mahabalipuram to the south, Chengalpattu and Maraimalai Nagar to the south west, Kanchipuram town, Sriperumpudur, Tiruvallur and Arakkonam to the west.

References

1. ^{{cite web | title=Practices and Practitioners – Chennai | work=Rainwater harvesting| url=http://www.rainwaterharvesting.org/Urban/Practices-and-practitioners.htm| accessdate=5 August 2005 }}
2. ^{{cite web|title=A ready reckoner on rainwater harvesting |work=Govt. of Tamil Nadu / New Indian Express |url=http://www.tn.gov.in/pressclippings/archives/pc2003/newindpress/newindpress11082003.htm |accessdate=5 August 2005 |archiveurl=https://web.archive.org/web/20050623074539/http://www.tn.gov.in/pressclippings/archives/pc2003/newindpress/newindpress11082003.htm |archivedate=23 June 2005 |deadurl=yes |df= }}
3. ^{{cite web|title=Climate of India |work=National Environment Agency – Singapore |url=http://app.nea.gov.sg/cms/htdocs/article.asp?pid=1111 |accessdate=4 August 2005 |deadurl=yes |archiveurl=https://web.archive.org/web/20061006131405/http://app.nea.gov.sg/cms/htdocs/article.asp?pid=1111 |archivedate=6 October 2006 |df= }}
4. ^{{cite news | title= Highest temperature | url=http://www.hinduonnet.com/2003/05/31/stories/2003053104790101.htm| publisher=The Hindu | date= 31 May 2003| accessdate=2007-04-25}}
5. ^{{cite news| title = Entering 2006, city's reservoirs filled to the brim | author = T. Ramakrishnan | url = http://www.hindu.com/2006/01/03/stories/2006010315310300.htm | publisher = The hindu | date = 3 January 2006 | accessdate = 2007-05-04}}
6. ^{{cite web|url = http://www.imdchennai.gov.in/climate/chennai2.htm|title = Chennai- Climatological Information|publisher = India Meteorological Department|accessdate = 1 September 2017|deadurl = bot: unknown|archiveurl = https://web.archive.org/web/20170901093121/http://www.imdchennai.gov.in/climate/chennai2.htm|archivedate = 1 September 2017|df = }}
7. ^{{cite web|last=India Meteorological Department|title=Ever Recorded Maximum Temperature, Minimum Temperature and 24 Hours Heaviest Rainfall up to 2010|url=http://www.imdpune.gov.in/Temp_Extremes/histext2010.pdf|publisher=India Meteorological Department, Pune |page=67 |accessdate=29 May 2014}}
8. ^{{cite web| url = ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/TABLES/REG_II/IN/43279.TXT | title = Madras (Chennai) Climate Normals 1971–1990| publisher = National Oceanic and Atmospheric Administration | accessdate = 25 March 2015}}
9. ^{{cite web|url=http://www.lifeinchennai.com/chennai_geography.htm|title=Chennai|publisher=lifeinchennai.com|accessdate=2009-07-27}}
10. ^{{cite web|title=Chennai Water Supply |work=Management of water supply during acute water scarcity in 2003 & 2004 |publisher=Chennai Metropolitan Water Supply and Sewage Board (CMWSSB) |url=http://www.chennaimetrowater.com/engg/operationmaintenance/cmwdrw04.htm |accessdate=2007-03-16 |deadurl=yes |archiveurl=https://web.archive.org/web/20070812071544/http://www.chennaimetrowater.com/engg/operationmaintenance/cmwdrw04.htm |archivedate=2007-08-12 |df= }}
11. ^"Bangalore team visits RWH structures in city", The Hindu, 3 August 2007, accessed 11 August 2007
12. ^{{cite web | title= General statistics | work=Corporation of Chennai | url=http://www.chennaicorporation.com/general_stats.htm| accessdate=4 August 2005 }}

1 : Geography of Chennai