TIRUVALLUR DISTRICT Thiruvallur district is spread over 3422 Sq. km. It is geographically located between between 12°15' and 13°15' Northern Latitude and between 79°15' and 80°20'Eastern Longitude. According to 2001 census, the total population is 27,38,866 which consists of 13,90,292 males and 13,48,574 females. The district is surrounded by Kancheepuram district in the South, Vellore district in the West, Bay of Bengal in the East and Andhra Pradesh State in the North. Agriculture is the chief occupation of the Thiruvallur district. Farmers of the district grow rice, black gram, green gram, sugar cane and groundnut. Horticultural crops like mango, guava and vegetables are also cultivated. Nearly 16940 small scale industries, are successfully running in the district some of them are wood, textile, chemical, engineering, non-metallic and leather industries. Google Map of Thiruvallur District District Map of Tiruvallur Administrative Details Tiruvallur district is having administrative divisions of 8 taluks, 14 blocks, 539 Panchayats and 805 villages as detailed below: Land Utilisation The total land under forest cover is 19736 hectares. The total cropped area in the district is 131172 hectares. About 47% of the total work force is engaged in agricultural and allied activities. The major crops grown in the district are rice, cumbu - ragi, green gram, black gram, sugar cane and groundnut. Apart from this, certain horticultural crops like mango, guava and vegetables have also been cultivated. Water Resource The district does not have a perennial river. The district has a number of seasonal rivers like Kesathaliar, Aravar, Nandi, Kallar,Coovam and Buckhingham Canal. To supplement the water supply to the district, irrigation is done through tanks, tube wells and open wells are very common. Revenue Divisions and Taluks Tiruvallur District consists of 4 Revenue Divisions and 12 taluks: Ambattur Revenue Division: Tiruvottiyur taluk, Madhavaram taluk, Ambattur taluk, Maduravoyal taluk, Avadi taluk Ponneri Revenue Division: Ponneri taluk, Gummidipoondi taluk Tiruvallur Revenue Division: Uthukkottai taluk, Tiruvallur taluk, Poonamallee taluk Tiruttani Revenue Division: Tiruttani taluk, Pallipattu taluk Tiruvottiyur, Madhavaram, Maduravoyal, Ambattur, Avadi, Poonamallee, Ponneri, and Tiruvallur taluks lie within the Chennai Metropolitan Area. Revenue Blocks and Municipalities The following are the Revenue blocks of the district. Ellapuram Gummidipoondi Kadambathur Minjur Pallipattu Poonamallee Poondi Pulal R.K.Pet Sholavaram Tiruvallur Tiruttani Thiruvalangadu Villivakkam There are 5 municipalities: Avadi (special grade) Thiruverkadu (selection grade) Poonamallee (grade I) Tiruvallur (grade I) Thiruthani (grade II) Geography It is bounded on the north by Andhra Pradesh state, on the east by the Bay of Bengal, on the southeast by Chennai district, on the south by Kanchipuram and on the west by Vellore district.The coastal region of the district is mostly flat and dreary; but in the other parts it is undulating and even hilly in some places. The northern taluks of the district like Ponneri, Uttukkottai, Gummidipundi etc. do not have much to offer from the scenic point of view. In the Tiruttani taluk, a number of hillocks are found scattered. The soil of the district is mostly sandy, mixed with soda or other alkali or stony. Rocks found in and near the surface are in detached masses. Hence, the soil can't be termed as very fertile. The soil found nearer the sea coast is of the inferior erinaceous type which is most suited for raising casuarinas plants. No mineral of any importance is available in the district. There are not many hills of any considerable height in this district. A few conical hills or ridges of small elevation exist like the St. Thomas Mount. Certain hillocks are found in Tiruttani. Most of the hills and hillocks are rocky and no verdant vegetation is seen in the slopes of these hills. The area under forests in this district is quite meager. Rainfall The average normal rainfall of the District is 1104 mm. Out of which 52% has been received during North East Monsoon period and 41% has been received during South West Monsoon period. Basin and sub-basin The district is part of the composite east flowing river basin having ArniarKorataliar and Cooum sub basins. Drainage Araniyar, Korattalayar, Cooum, Nagari and Nandhi are the important rivers. The drainage pattern, in general, is dendritic. All the rivers are seasonal and carry substantial flows during monsoon period. Korattaliar river water is supplied to Cholavaram and Red Hill tanks by constructing an Anicut at Vellore Tambarambakkam. After filling a number of tanks on its further course, the river empties into the Ennore creek a few kilometres north of Chennai. The Cooum river, flowing across the southern part of the district, has its origin in the surplus waters of the Cooum tank in Tiruvallur taluk and also receives the surplus waters of a number of tanks. It feeds the Chembarambakkam tank through a channel. It finally drains into the Bay of Bengal. Geomorphology The prominent geomorphic units identified in the district through interpretation of Satellite imagery are 1) Alluvial Plain, 2) Old River Courses 3) Coastal plains 4) Shallow & deep buried Pediments, 5) Pediments and 6) Structural Hills. The elevation of the area ranges from 183 m amsl in the west to sea level in the east. Four cycles of erosion gave raise to a complex assemblage of fluvial, estuarine and marine deposits. The major part of the area is characterised by an undulating topography with innumerable depressions which are used as irrigation tanks. The coastal tract is marked by three beach terraces with broad inter-terrace depressions. The coastal plains display a fairly lower level or gently rolling surface and only slightly elevated above the local water surfaces or rivers. The straight trend of the coastal tract is resultant of development of vast alluvial plains. There are a number of dunes in the coastal tract. Soils Soils in the area have been classified into i) Red soil ii) Black soil iii) Alluvial soil iv) colluvial soil. The major part is covered by Red soil of red sandy/clay loam type. Ferrugineous red soils are also seen at places. Black soils are deep to very deep and generally occurs in the depressions adjacent to hilly areas, in the western part. Alluvial soils occur along the river courses and eastern part of the coastal areas. Sandy coastal alluvium (arenaceous soil) are seen all along the sea coast as a narrow belt. Status of Ground Water Development The estimation of groundwater resources for the district has shown that 6 blocks are over exploited and 2 blocks are under “critical” category. The shallow alluvial aquifers along Korattalaiyar and Araniyar rivers serve as an important source of drinking water for Chennai Metropolitan area and 5 well fields have been constructed in Tiruvallur district for the purpose. The well fields have a combined yield of 36.50 MCM/year. The water supply details of the well fields are furnished below. Dug wells are the most common ground water abstraction structures used for irrigation in the district. The yield of dug wells range from <50 to 200 m3/day in weathered crystalline rocks, 20 to 100 m3/day in Gondwana formations and upto 400 m3/day in Recent alluvial formations along major drainage courses.The dug wells in hard rock terrain tapping the entire weathered residuum are capable of yielding 6 – 7 lps, requiring the installation of 5 HP centrifugal pumps for extraction of ground water. .