Context: The climate change experienced in recent years has not only changed the rainfall pattern but also accentuated water scarcity across India. In many parts of Tamil Nadu, for instance, people meet their daily needs by paying ₹10 for a bucket of water.
Scenario
- Ministry of Water Resources indicate that the demand for water will exceed supply by 2050 due to increased requirement for industry and agriculture.
Tank Irrigation and associated benefits
- Tank is main water source for Tamil Nadu since centuries.
- State has tank with total storage capacity of 347 TMC (thousand million cubic feet) which is more than total storage of all dams of Tamil Nadu.
- Tanks provide water for all activity at lower cost.
- Unlike large dams, tanks are easy to manage due to their small size.
- The maintenance cost of tanks is also very low as compared to canal irrigation.
- Unlike canal irrigation, conflicts between tail-end and head-reach farmers are negligible under tank irrigation.
- Increased storage of water in tanks helps in recharge of wells, reducing the over-exploitation of groundwater.
- The tanks located in every village prevent women from having to walk long distances to fetch drinking water.
Declining Tank Infrastructure:
- Tank irrigated area in India decreased from 46.30 lakh hectares in 1960-61 to 22.05 lakh hectares in 2021-22.
- The share of tank-irrigated area to net-irrigated area has consistently declined from 38 per cent in 1960-61 to 14 per cent in 2022-23 in Tamil Nadu.
- The data from the Central Groundwater Board (March 2020) show that of the 1,166 blocks in Tamil Nadu, 723 are classified as over-exploited.
- Despite above-average rainfall, tank-irrigated area in Tamil Nadu has not increased.
Causes of Decline:
- Rapid urbanization leads to encroachment of water-spread areas for construction, reducing water storage capacity.
- Neglect and poor maintenance contribute to the defunct status of many tanks.
- Municipal and panchayat bodies encroach upon tanks for various purposes, as highlighted in government reports.
Consequences:
- Sharp decline in area irrigated by tanks impacts agricultural productivity.
- Encroachment exacerbates water scarcity, leading to over-exploitation of groundwater.
Proposed Solutions:
- Repair, renovate, and restore tanks to increase storage capacity.
- Remove encroachments on catchment areas and water-flow channels to facilitate rainwater flow to tanks.
- Implement bans on construction activities near tank locations, respecting legal judgments.
- Allocate funds for regular maintenance and modernization of tanks, possibly through partnerships with corporates under CSR schemes.
- Emphasize repair of water-flow channels to ensure proper water retention.
Addressing Climate Change Impacts:
- Climate change exacerbates water scarcity, with below-average rainfall becoming more common.
- Initiatives must focus on increasing tank storage capacity to mitigate the effects of reduced rainfall and ensure water availability in the face of climate change.
- The Central Ground Water Board (CGWB)Central Ground Water Board was established in 1970 by renaming the Exploratory Tube wells Organization.
- It is under the Ministry of Jal Shakti.
- Its responsibilities include providing scientific inputs for management, exploration, monitoring, assessment, augmentation, and regulation of groundwater resources across the country. The CGWB collaborates with the Central Ground Water Authority (CGWA) to regulate and control groundwater development and management