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.
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, Kosasthalaiyar, 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:
Actual Rainfall in mm | Normal Rainfall in mm | ||||
---|---|---|---|---|---|
2017 | 2018 | 2019 | 2020 | 2021 | |
1198.0 | 733.4 | 1174.2 | 1229.0 | 1809.6 | 985 |
Geology:
Rock Type | Geological Formation | ||||
Sedimentary Rock 80% Hard Rock 20% |
Charnockite, Gneiss, Conglomerate, Sandstone, Shale, Laterite, Alluvium and Marine deposits |
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 |
May |
Jan |
May |
Jan |
May |
Jan |
May |
Jan |
May |
5 Years |
5Years |
8.5 |
13.9 |
8.9 |
21.7 |
9.5 |
12.3 |
8.5 |
15.3 |
5.9 |
14.7 |
13.1 | 7.3 |
Sustainability:
With a view to enhance the Sustainability of the drinking water sources, recharge structures are being implemented by TWAD Board under various State and Central Government assistances.
The Recharge Structures implemented so far in district is as under.
Recharge Structures | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Check Dam | Percolation Pond | Recharge Pit | Recharge Trench | Others | Ooranies | Defunct Bore well Recharge | Recharge Shaft | Rooftop RWH | Hydro Fracturing | Total |
368 | 13 | 15 | 41 | 437 |
Categorization of Firkas:
The status of Categorization of firkas as of March 2020 for the District in is shown below.
Categorisation based on Extraction (as on 2020) | No. of Firkas | Firkas |
---|---|---|
Over Exploited (>100%) | 7 | Avadi, Poonamallee, R.K.Pet, Thiruninravur, Tirumullaivoiyal, Vayalanallur, Vellanur |
Critical (90%-100%) | 2 | Tiruttani, Vengathur |
Semi Critical (70%-90%) | 17 | Balapuram, Cherukkanoor, Erumbi, Kanagammachattram, Kannigaipair, Manavor, Mappedu, Morai, Nemam, Pallipattu, Poondi, Poonimangadu, Puzhal, Thirumazhisai, Tirur, Uthukkottai, Velliyur |
Safe (<70%) | 20 | Ammanambakkam, Arani, Elavur, Gnayiru, Gummidipoondi, Kadambathur, Kattur, Kolur, Madharpakkam, Pandur, Pennalurpett, Periyapalayam, Ponneri, Poovalambedu, Pothattur Pettai, Sholavaram, Thirupalaivanam, Thiruvallur, Thiruvalangadu, Velakapuram |
Others (Poor & Saline) | 1 | Minjur |
Total | 47 |
Rural Habitations
Total No. of Rural Habitations: 3842
Partially covered | 64 (10-39 lpcd ) |
Fully covered | 3778(40 lpcd and above) |