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A. Background 1. These terms of reference (ToR) outline the scope of works, deliverables and work project for the firm Topography survey - Cauvery. The Topographical survey firm shall conduct survey in the Cauvery sub basin for Water Resources Department, Tamil Nadu for the implementation of the Climate Adaptation in Vennar Sub-basin in Cauvery Delta project (CAVSCDP). 2. Agriculture is the dominant employment sector in Tamil Nadu and it provides livelihoods for nearly 45% of the population. However, the sector’s contribution to state gross domestic product (GDP) fell from 11.1% in 2004-05 to 8.2% in 2010-11. Estimated total water demand in Tamil Nadu in 2001 was 54,395 MCM mainly for irrigation (50,007 MCM), industry/power/livestock (2,192 MCM) and drinking (1,445 MCM) compared to an estimated annual water potential including surface (24,864 MCM) and groundwater (22,423 MCM) is assessed of 46,540 MCM. While the total demand is forecast to go up to 57,725 MCM by 2050, usage for irrigation is not expected to increase significantly because of demand for land for urbanization. 3. There are 17 major river basins in the state, of which the Cauvery basin (81,115 km²) is the largest. About 90% of surface water is used in irrigation. The Cauvery River basin spans the states of Karnataka, Tamil Nadu, Kerala, and part of the Union Territory of Pondicherry. According to the decision of the Cauvery Waters Dispute Tribunal in 2007, 58% (11,865 MCM in average year) of the surface water resources of the basin are allocated to Tamil Nadu. The total potential irrigation demand in the Cauvery delta, excluding irrigation demand upstream of the delta and other water uses, exceeds the available resource. 4. The Cauvery Delta (6900 km²) has a total population of about 4.8 million, with about 73% relying on farming and fishing. There are four main irrigation systems in the delta: (i) Lower Coleroon Anicut (53,000 ha), (ii) Cauvery (200,000 ha), (iii) Vennar (190,000 ha), and (iv) Grand Anicut (121,000 ha). Key constraints faced by the Cauvery Delta farmers are: (i) difficulty in planning of annual cropping pattern due to the lack of assurance about surface water availability; (ii) in efficient distribution and application of water; (iii) in equitable access to water resources with downstream users have intermittent access to surface water and poor access to suitable quality ground water, (iv) crop damage during the north east monsoon due to flooding and poor drainage in coastal areas. The three districts in the Vennar System (Thanjavur, Thiruvarur, Nagapattinam) record the lowest average rice productivity in Tamil Nadu. 5. Climate change is expected to worsen the already challenging situation. The projections indicate much drier conditions between January and May but wetter and warmer conditions during the irrigation season (June to December). However the climate projections also show large increases in storm rainfall and runoff. Therefore more frequent and serious flooding can be expected. Flooding in coastal areas will gradually be exacerbated by rising sea levels. 6. The key management issues facing the water resources sector are: (i) inadequate planning and stakeholder participation in resource management, (ii) limited demand management, (iii) no effective use of economic incentives and penalties to reduce pollution and wastage, (iv) WRD’s mandate and skill set is in irrigation supply will little emphasis on water resources management, (v) under-investment in infrastructure due to the Cauvery waters dispute, (vi) inadequate funding for operation and maintenance, and (vii) flood management is reactive with minimal planning for flood risk mitigation. 7. The Project will contribute to the initial improvement of water resources management in the Cauvery Delta. B. The Project 8. The project comprises two outputs: (i) flood risk management and irrigation infrastructure upgraded, and (ii) improved water and flood risk management systems established. Under Output 1, the project will support the (i) repair and upgrading of existing infrastructure including embankments designed to withstand a 25 year return flood taking into consideration climate change projections, and (ii) construction of new essential infrastructure. Output 2 will deliver non- structural adaptations designed to improve the management of surface water resources, and manage flood risks and flood events. Initiatives to be developed are: (i) improved assessment of water resources through installation of additional rainfall, surface water level, groundwater level and tide level monitoring stations and through direct flow measurements at key structures, (ii) development of a Decision Support System (DSS) and (iii) capacity development of Water Resources Department officers in improved management of water resources. The improvements to management of flood risks and flood events will be achieved through establishment of flood forecasting and warning systems and preparation of flood risk maps. C. Implementation Arrangements 9. The executing agency is the Water Resources Department. A Project Management Unit (PMU) has been established. The PMU is headed by a full time Project Director of Chief Engineer Rank. The PMU is supported by Project Implementation Units (PIUs) established in the respective EEs offices. Five PIUs have been established in Thiruvarur; Nagapattinam; Thiruthuraipoondi; Vennar Basin Division, Thanjavur; and Cauvery Basin Division, Thanjavur. The PMU is supported by two teams of consultants: (i) Project Implementation Consultants supporting Output 1 on implementation and establishment of channel stakeholder groups, (ii) Project Technical Advisory Consultants (PTAC), under Output 2, who will (a) support the implementation of the establishment of a decision support system, and flood risk mapping and establishment of forecasting and warning systems under Output 2 in the project, and (b) support the preparation of feasibility studies for a follow on project covering the remainder of the Vennar Subbasin and Cauvery Subbasin (hereinafter referred to as follow on project). D. Scope of Survey Works 10.Topographical surveys of the canal and drainage network of the coastal part of the Cauvery Main River are required to support the PTAC, modeling and development of a digital elevation Model (DEM). These two outputs need to be completed prior to the main consulting. The Topographical Survey for the subbasins, Pandavaiyar, Harichandranathi, Mulliyar, Koraiyar, Paminiyar, Vedharanyam are completed. This Topographical Survey is for the channels of the main Cauvery River in the delta portion.
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