Irrigation Source of Tamilnadu

Irrigation is the artificial application of water to the soil for growth of plants.

Tamil Nadu

The areas covered by different types of irrigation are extensive in certain districts and negligible in others. Wide variations are seen in the net area irrigated in the different districts. Thanjavur leads with 4.5 lakh ha under irrigation and Nilgris has the least extent with about 500 ha only. This is due to absence of natural resources like rivers. The existence of big river contribute to the development of flow irrigation as in Thanjavur. The soils of South Arcot, North Arcot and Chengai are very permeable, the rainfall is very generous and these have contributed to a high underground water table. Lift irrigation from wells has developed here.

Sources of Irrigation

Water is an important determinant factor of production of crops in agriculture sector. Intensive and extensive cultivation of land depend mainly on the availability of water. Medium and minor irrigation schemes are implemented in the state for augmenting the irrigation for agriculture.

The various sources of irrigation are canals, tanks, tube wells, Open wells and springs. The number of sources of irrigation are furnished in the following table.

Source: Season and Crop Report of Tamil Nadu 2009 – 2010

Area Irrigated: The net area irrigated by different sources during 09-10 was 2863866 ha as against 2931113 ha in 08-09 showing a decrease of 67247 ha or 2.3% over the previous year.  The net area irrigated during 09-10 constituted 56.8% of the net area sown in the state. Villupuram district is at the top with 236484 ha net area irrigated. However the highest percentage of the net area irrigated to the net area sown was recorded in Thiruvarur District with 97.4% followed by Thanjavur District with 85.6% and Kancheepuram with 85.0% whereas the lowest percentage was recorded in The Nilgiris district with 0.5%. The following table shows the net area irrigated by various sources compared with 08-09.

Canals (Including System Tanks): Canals are the major source of irrigation in Tamilnadu. As the system tanks get supply from a permanent storage like reservoirs, dams etc. the area iirigated by this -source is classified under canals. During   09-10, Canal irrigation accounted for 26.4% the net area irrigated by all sources in the state. The net area irrigated by canals including system tanks during the year was 757090 ha as against 765527 ha in 08-09  recording an decrease of 8437 ha i.e. 1.1%. The net area irrigated by canals is the highest in Thiruvarur district with 150564 ha (19.9%) followed by Thanjavur district with 134554 ha (17.8%) and Nagapattinam district with 123696 ha (16.3%) of the total net area irrigated by canals in the State.  

Tanks (Non-System Tanks Only): The non-system tanks which are fed partly from their independent catchment areas and partly from the diversion of river water and jungle streams depend fully on rain. The net area irrigated by non-system tanks during the year 09-10 is 503491 ha as against 540281 ha in 08-09 registering a decrease of 36790 ha or 6.8% over previous year.  The extent of area irrigated by tanks during the year is the highest in Pudukottai district with 14.9% followed by Kancheepuram district with 13.6% and Sivagangai district with 12.8%.

Wells: Wells are the principal source of irrigation in Tamilnadu. During the year under review, open wells and tube-wells/bore-wells continued to be the principal source of irrigation.  The net  area irrigated  by open wells and tube-wells / bore-wells together    accounted for 1593968 ha (about 55.7 % of the total net area irrigated) in 09-10 as against 1614082 ha in 08-09 showing a decrease of 20114 ha i.e. 1.2%.   The net area irrigated by wells during the year 09-10 was the highest   in Villupuram district with 11.3% of the total net area irrigated by the wells in the state followed by 7.7% in Thiruvannamalai district and 6.4% in Salem district.