Subsurface dykes across river increase groundwater levels in Tiruvarur Subsurface dykes have been constructed on the upstream side of some rivers branching from River Cauvery in Tiruvarur district of Tamil Nadu with a view to increasing ground water levels. This was reported by the Jal Shakti Abhiyan (JSA) team that has been working with the district administration to put in place effective measures to conserve water in the water stressed region. A subsurface dyke is a structure that is built in an aquifer, with the intention of obstructing the natural flow of ground water; thereby raising the ground water level and increasing the amount of water stored in the aquifer. The JSA team comprised Central Nodal Officer (CNO) – Shri Piyush Srivastava, Additional Development Commissioner, M/o Micro, Small and Medium Enterprises, Delhi; Block Nodal Officer (BNO) - Shri U. K. Nair, Deputy Secretary, Ministry of Steel, Delhi and Technical Officer (TO) - Mr. Neeraj Kumar Sharma, Deputy Director, Central Water Commission, Department of Water Resources, River Development and Ganga Rejuvenation, Ministry of Jal Shakti, Delhi. The JSA team made 3 visits to Kodavasal Block, Agarathirumalan firka in Nannilam Block and Alangudi and Avoor firkas in Valangaimen Block in the southern district over the past 3 months (I visit – 11th to 13th July; II visit – 6th to 8th August; and III visit – 24th to 25th September, 2019). According to Mr. Neeraj Kumar Sharma, the Department of Rural Development and Panchayat Raj (DRD&PR) constructed a 35 metre long sub surface dyke across Kudamurthy River in Vadaver panchayat of Kodavasal Block. The project was implemented under MGNREGS using funds from the 14th Finance Commission and General Fund (2017-18) at an estimated amount of Rs. 9.23 lakhs. The work was successfully complemented in September-October 2019 at a cost of Rs. 12.25 lakhs. The sub-surface dykes were placed at 1.2-1.3 m below the bed level of river and about 5.5 m below ground level of surface. Earlier, ground water stood at around 90-100 feet. District officials now say that the river is flowing with water owing to two reasons - release of Cauvery water from Mettur dam of Karnataka; and rainwater. Ground water now stands at 40-70 feet. Rooftop Rainwater Harvesting System (RRHS): A RRHS system has been setup atop the 4500 sq. ft roof Panchayat Union office building in Kodavasal Block. The project has been executed by DRD&PR under MGNREGS (2018-19) for an estimated amount of Rs. 2.70 lakhs. Given that the average rainfall during the last ten years was 900 mm and considering 0.8 as runoff coefficient, the water available from the roof would amount to 3,01,160 litres. Another RRHS was set up for the Valangaiman Block Development Office Building under MGNREGS for an estimated amount of Rs. 3.70 lakhs. For the 300 sq. ft area of the roof covered, the water holding capacity of storage tank is estimated at 20000 litres. Community Soak Pit: A community soak pit measuring 1.5mX1.5m has been constructed in Veeravadi village in Agarathirumalam panchayat of Nannilam Block by the DRD&PR at an estimated cost of Rs. 9600. The project has increased ground water table from 35-40 feet to 20-24 feet. Water absorption trenches: DRD&PJ has also formed trenches in Pasana Vaikkal and Vadikal at Maharajapuram Panchayat, Agarathirumalam / Nannilam Block under MGNREGS (2019- 20) for an estimated cost of Rs. 7,46,000. Of the targeted 800 trenches, 200 were completed upto September, 2019. The water holding capacity of the 800 trenches would be 2640 cubic meters. The remaining trenches will be completed after North-East monsoon i.e. from December 2019 onwards. Intensive Afforestation: DRD&PR has undertaken massive tree plantation in Periya Kulakarai village in Maruthuvancheri Panchayat of Agarathirumalam/Kodavasal Block under MGNREGS for an estimated amount of Rs. 1,87,000. The size of plantation is 1 acre comprising about 280 saplings of native species such as teak, mahogany, pomegranate, guava, Kumuli etc., and the nursery has been raised in the same location. Mass awareness campaign: A mass awareness campaign was organised in Valangaimen Block on 13th July, 2019 that saw the participation of JSA officials along with their Liaison Officers, Block Development Officer (BDO), State Government officials from Department of Public Works Department (PWD), Department of Agriculture Engineering and Department of Rural Development. School children, teachers and locals participated enthusiastically in the awareness campaign, supported by SHGs, Swachhagrahis, Jal Sahiyas, Sarpanchs, volunteers, NGOs, etc. .