Chapter 1 Introduction
Total Page:16
File Type:pdf, Size:1020Kb
Chapter 1 Introduction 1.1 General Water is the most essential natural resource next to air, required for sustaining life on the earth. It is required for drinking and industrial uses, for irrigation to meet the growing food and fiber needs, for power generation, navigation and recreation. The development, use and conservation of water, therefore, play a vital role in the country's development planning. The water resources in the country are, however, limited considering the future demands. The rainfall in the country is mostly confined to monsoon season and is unevenly distributed with respect to both space and time. As a result, some parts of the country are affected by frequent droughts whereas other parts are affected by floods. Nearly one third of the country is drought prone. In the very near future, water will become a scarce resource due to increasing thrust of population and increasing demands for various uses. Therefore, it need not be emphasised that water should be harnessed in the most scientific and efficient manner. The monsoon flood waters should be conserved to the maximum extent possible to meet the demands for irrigation, power generation, domestic and other uses. The water availability and requirements in the various river basins need to be assessed realistically. The reasonable basin requirements should be provided for and the surplus water, if any, should be transferred to the needy areas. The National Water Policy adopted by the Government of India in September, 1987 emphasizes that water should be made available to water short areas by transfer from other areas including transfers from one river basin to another, based on a national perspective. 1.2 National Perspective Plan for Water Resources Development The erstwhile Union Ministry of Irrigation (now Ministry of Water Resources) and the Central Water Commission in the year 1980 formulated the National Perspectives for Water Resources Development, 1 i.exe which comprises two main components, viz. Himalayan Rivers Development and Peninsular Rivers Development. Himalayan Rivers Development envisages construction of storage reservoirs on the main Ganga and the Brahmaputra and their principal tributaries in India and Nepal alongwith inter-linking canal systems to transfer surplus flows of the eastern tributaries of the Ganga to the West apart from linking of the main Brahmaputra with the Ganga. Peninsular Rivers Development of the National Perspectives Plan includes interlinking of major rivers flowing in the Peninsular India including the southern tributaries of Yamuna. The major parts of this components are (i) interlinking of Mahanadi-Godavari-Krishna-Pennar-Cauvery, (ii) interlinking of west flowing rivers, north of Bombay and south of Tapi, (iii) interlinking of Ken with Chambal and (iv) diversion of west flowing rivers. The interlinking of these rivers will envisage construction of storage reservoirs at potential sites and canal systems for transferring the waters from surplus to deficit basins/areas. The canals will also include tunnels and lifts, wherever necessary. 1.3 Cauvery (Kattalai)-Vaigai-Gundar Link The Cauvery (Kattalai)-Vaigai-Gundar link which forms a part of the scheme of transfer of surplus river water of Mahanadi and Godavari rivers to the deficit basins of Krishna, Pennar, Cauvery and Vaigai, is an important part of the various inter-basin water transfer proposals envisages under the Peninsular Rivers Development component of the National Perspective Plan. The proposed link project comprises of the following components: i) A barrage at Kattalai across the Cauvery River with pond level 101.20 m ii) A head regulator on the flank of the extreme right bank with a design discharge capacity of 180.30 cumecs. iii) A 255.60 km long link canal taking off from the proposed head regulator with FSL at 100.75 m and designed capacity of 180.30 cumecs. It is proposed to divert a quantity of 2252 Mm3 from Kattalai barrage through the proposed link canal. It is envisaged that this link canal will provide en route irrigation to a culturable command area of 337717 ha 2 utilising 1952.30 Mm3 of water besides providing 185 Mm3 of water for meeting domestic and industrial requirements. 1.4 Description of the Project Area 1.4.1 Location (a) Kattalai Barrage The Cauvery (Kattalai) – Vaigai - Gundar link project lies entirely in Tamil Nadu. The location of the proposed Kattalai barrage is at about 138 km downstream of the Mettur dam on the river Cauvery. The drainage area of Cauvery basin up to the proposed barrage site is 63694 km2. The barrage is proposed to be constructed 500 m downstream of the existing Kattalai Bed Regulator which will be abandoned when the new barrage is constructed. The proposed barrage is accessible by road from Chennai, Coimbatore and Tiruchchirappalli, the distances being approximately 375 km, 175 km and 60 km respectively. Mayanur railway station located on Tiruchchirappalli - Erode Broad Gauge line is just adjoining the head works. (b) Canal Head Regulator The existing South bank canal, the Kattalai high level canal, Krishnarajapuram channel and the New Kattalai high level canal take – off on the right flank of the existing Kattalai bed regulator. Considering the size, FSL and slope of these existing canals, none of them will be suitable for the purpose of the present link canal proposal without extensive renovation. Hence, it is proposed to have an independent off– take for the proposed link canal upstream of the existing New Kattalai high level canal on the right bank of the river at a distance of 600 m upstream of the proposed barrage. The proposed head regulator would have 4 bays of 10.75 m span. (c) The Link Canal The Cauvery (Kattalai) – Vaigai - Gundar link canal is proposed as a contour canal running for a total length of 255.60 km till it joins with Gundar river. The link canal is aligned through Krishnarayapurm, Kulithalai taluks of Karur district; Srirangam and Tiruchchirappalli taluks of Tiruchchirappalli district; Kulathur, Pudukkottai, Gandarvakkottai, Alangudi, Arantangi, Thirumayam and Avudayarkoil talukas of Pudukkottai district; Karaikudi, Devakottai, Ilaiyankudi, Tirupattur, 3 Sivaganga and Manamadurai talukas of Sivaganga district; Tiruvadanai, Paramakudi, Kamudi, Ramanathapuram, Kadaladi and Mudukulathur taluks of Ramanathapuram district; Tiruchuli, Kariyapatti and Aruppukkottai talukas of Virudhunagar district. 1.4.2 Climate The climate of the command area, through which the link traverses, is basically tropical in nature. The mean daily maximum temperature in the command area ranges from 29.3o C to 37.5 0C. During the hottest month, i.e., May, the temperature varies from 37.1o C to 37.5o C. Mean daily minimum temperature varies from 20.6o C to 26.5o C. During the coolest month, i.e., January, the temperature varies from 20.6o C to 20.9o C. The annual rainfall in the command area varies from 635 to 1019 mm. The summer season starts by about March and continues till May. Thereafter, the south-west monsoon season follows and lasts up to September. North-east monsoon sets in by mid-October and ends during mid-December. During the north-east monsoon period, the coastal belt of Tamil Nadu receives more rainfall. The cold weather period from mid- December to February is a season of generally fine weather. 1.4.3 Topography, Physiography and Geology of the Area The canal mostly runs in plain area except at the crossings of ridges between various river basins en route. Major soil types encountered along the alignment are black cotton and red sandy soils. From the off-take point to a distance of 130 km, the link canal passes through Archaean metamorphic terrain consisting of migmatitic and hornblende biotite gneiss. The thickness of weathered zone is fairly high at 10 – 15 m up to RD 50 km. In Pudukkottai area, fresh rock is seen at shallow depth of 1-2 m. Sedimentary formations of Upper Gondwana (Sivaganga formations) and mio-pliocene (Cuddalore formations) ages occupy remaining stretch of canal. Horizontally bedded gravel, sand, shale and clay which constitute these formations are capped by laterite intermittently. The canal traverses through alluvial tract of about 10 km in Vaigai basin. 4 1.4.4 Population The submergence area of the barrage proposed at Kattalai, at its maximum pond level of 101.200 m, lie fully within the flood banks of Cauvery River and hence no agricultural or inhabited area is coming under submergence. The human population in the command area is 18.95 lakh of which 5.99 lakh in urban. Considering Pudukkottai, the largest district lying in the command, as a representative district, out of the total workforce, 34% are agricultural workers, 37% are cultivators, 2% are workers of house hold industry, 22% are marginal workers and 5% are other workers. Similarly, the people living in the districts situated further south, which will be benefited by the diverted water, are mainly dependent upon agriculture. 1.4.5 Natural Resources No significant mineral resources are available in the command area. However, small traces of minerals like lime stone, gypsum, bauxite, feldspar, etc. are indicated to exist in the command area. 1.4.6 Landuse and Socio-economic Aspects The command area of the link project lies in Karur, Tiruchchirappalli, Pudukottai, Sivaganga, Ramanathapuram, Virudhunagar and Thoothukudi districts of Tamil Nadu State. The gross command area of the project is assessed to be 605123 ha, of which the total cropped area is 219073 ha (excluding existing irrigated area of 73878 ha) cultivated during north-east monsoon. Apart from the above, fallow land is estimated to be 147265 ha and forest area 29803 ha. People comprising more than 70% of the population in the command area are dependent on agriculture. The literacy rate is less than 70%. More than 92% of the agricultural land holdings are small.