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Wednesday , 14th April 2021
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Thiruvellore District Profile

  • Thiruvallur district is the northern most coastal district of Tamil Nadu.
  • The district is bounded by the Bay of Bengal in the East, Vellore district of Tamil Nadu and Chittoor district of Andhra Pradesh on the West, Nellore district of Andhra Pradesh on the North and on the South by Kancheepuram district.
  • It lies between 12º 55'N to 13º 34'N Latitude, 79º 17'E to 80º 21'E Longitude and has an areal extent of 3550 sq.km.
  • There are 14 Blocks, 526 Villages and 3842 Habitations in the District.

Physiography and Drainage

  • Thiruvallur district varies from featureless pediplain to residual and structural hills.
  • The Thiruthani and R.K.Pet hills form part of the important landmarks. The Coastal tract is marked by beach ridges with a general slope towards the east.
  • The Araniar, Kortaliyar, Adayar and Coovum are important rivers draining the district.
  • The Araniar originating in Andra Pradesh flows between Ponneri and Thiruvallur taluks and joins the Bay of Bengal near Pulicat.
  • The Coovum has its origin in the Surplus water from the Coovum tank in Sriperumbudur taluk and feeds the Chembarampakkam tank through a Channel.
  • The Poondi reservoir and Red hills are important tanks. The Pulicat tank is considered to be an important lagoon.

Rainfall:

The average annual rainfall and the 5 years rainfall collected from IMD, Chennai is as follows:

Acutal Rainfall in mm Normal Rainfall in mm
2013 2014 2015 2016 2017 2018
1067.0 938.10 2015.8 814.2 1198.5 733.4 1139.6

Geology:

Rock Type Geological Formation
Sedimentary Rock 80%,Hard Rock 20% Charnockite, Gneiss, Conglomerate,Sandstone, Shale, Laterite,Alluvium and Marine deposits

Hydrogeology:

Type of Aquifer Water table conditions in Hard Rock Areas.
Aquifer parameters Hard rock Alluvial formation
Well yield in lpm 45 – 220 150 – 400
Transmissivity (T)m2/day 10 – 80 >200 – 300
Permeability (K)(m/day)) 0.5 – 2.5 20 - 30
Depth of Water level 5m to 12.5m

Sustainability:

With a view to enhancing the Sustainability of the drinking water sources, recharge structures are being implemented by TWAD Board under various State and Central Government assistance.

The Recharge Structures implemented so far is as under.

Groundwater Potential as on March 2011 (as per CGWB):

Net Groundwater Availability (in MCM) 728.40
Existing Gross Groundwater draft for all users (in MCM) 492.89
Stage of Groundwater development (in %) 68%
Categorization of District Safe

Categorization of Firkas:

The status of Categorization of Firkas as of March 2013 for the District is shown below.

Categorisation based on Extraction (as on March 2013) No. of Firkas Firkas
Over Exploited (>100%) 4 Ambattur, Cherukkanoor, R.K.Pet, Vengathur
Critical (90%-100%) 8 Uthukkottai, Balapuram,Erumbi, Kadambathur,
Mappedu, Gummidipoondi, kannigaipair,Thirunindravur.
Semi Critical (70%-90%) 14 Kanagammachattram, Kattur,
Madhavaram, Periyapalayam,
Poonamallee, Poonimangadu, Pothattur
Redhills, Thirumazhisai, Tiruttani,Ammanbakkam, Avadi, Pallipattu, Morai, Velakapuram.
Safe (<70%) 19 Elavur, Gnayiru, Kolur,
Madhapakkam, Maduravoil, Manavor, Pothatturpettai
Pandur, Pennalurpett, Ponneri,
Poondi, Poovalambedu, Sholavaram, Arani
Thirupalaivanam, Thiruvalangadu,
Thiruvallur, Tirur, Velliyur.
Others (Poor& Saline) 1 Minjur
Total 46  
Water supply status as on 1.4.2018

Rural Habitations

Total No. of Rural Habitations: 3842

Partially covered 64 (10-39 lpcd )
Fully covered 3778(40 lpcd and above)

Urban Towns ( Water supply status - 1.8.2019)

S.NO Name of Towns Population Present water supply level LPCD
Municipalities
1 Thiruvallur 56074 92
2 Avadi 345996 50
3 Poonthamallee 60607 85
4 Thiruthani 44728 42
5 Thiruverkadu 62824 85
Town Panchayats
1 Naravarikuppam 20946 72
2 Thirunindravur 37095 73
3 Thirumazhisai 19733 100
4 Gummudipoondi 18891 117
5 Pallipattu 8721 73
6 Arani 12833 97
7 Ponneri 31025 111
8 Pothatturpettai 22040 80
9 Uthukottai 12740 70
10 Minjur 28337 79

Ground Water Level:

The Ground Water levels from the 35 number of observation wells of TWAD have been analysed for Post-Monsoon and Pre-Monsoon. 5 years average Ground water level in m Below Ground Level for pre and post monsoon is as follows:

Jan
2013

May
2013

Jan
2014

May
2014

Jan
2015

May
2015

Jan
2016

May
2016

Jan
2017

May
2017

Jan
2018
May
2018
Jan
2019
May
2019

5 Years
Pre Monsoon
Average

5Years
Post Monsoon
Average

3.80

12.82

9.80

13.87

13.06

12.66

6.95

9.54

12.5

19.1

8.9 21.7 9.5 12.3

8.6

13.8