Maharashtra has no plans to prevent evaporation in dams

AURANGABAD: Even as over 800 irrigation projects from Marathwada lose water to evaporation in a time of drought, the state government has not earnestly attempted to explore using solar panels to contain water loss.
The state power utility last December invited tenders to generate power from floating solar panels from Ujjani Dam in Solapur district, for the first time.The initiative is expected to produce renewable energy and prevent loss of water from evaporation. Also, the revised Drought Manual released by the Centre in 2016 advocated the use of chemical retardants to minimize evaporation losses in dams, especially in drought-prone areas. The chemical retardant process, however, was tried and found not quite satisfactory.
Official reports say different dams in drought-prone Marathwada lose about 46 TMC of water every year, accounting for nearly 17% of total live storage capacity. In the wake of deficient monsoon of 2018, eight of 11 major irrigation projects from the region have already hit dead storage in Marathwada, leading to a major water crisis. A total of 28 out of 75 medium irrigation projects have become absolutely dry. Of the 749 minor projects, 306 have run dry.
Shankar Nagare, expert member (irrigation) of Marathwada Development Board, said viable options for containing evaporation losses must be explored without wasting time. “The option of using solar panels to cover the water surface of dams can be an effective solution and must be tried at some of the key projects. Also, search for modern evaporation retardants that can be used for at least minor projects or farm-ponds from the region must be also explored,” he said.
PS Patil, central public relation officer of MSEDCL, said other major irrigation projects from the state could be considered for producing solar power after the successful implementation of the floating solar power project at Ujjani dam. “The demand for floating solar power projects on reservoirs would be conveyed to the top brass,” he said.
Besides the Drought Manual, the Central Water Commission and the State Water Policy in the past underlined the need to use chemical treatment to contain evaporation losses. A layer of chemicals like cetyl, steary and fatty alcohol emulsions when applied on the water surface can help reduce evaporation. It has been reported that fatty alcohol emulsions can effectively retard evaporation, saving around 40% of the normal evaporation losses, the manual adds.
The drought manual lists Deccan Plateau that comprises Maharashtra along with West Rajasthan, Saurashtra and Southern Coastal regions of Tamil Nadu, where the evaporation rate is relatively quite high. The manual, which has been prepared by the Ministry of Agriculture and Farmers Welfare of Centre, has recommended such measures after suitable bio-degradability study and bio-hazard assessment. It also asks for necessary approvals from the respective pollution control and other regulatory authorities.
Ajay Kohirkar, executive director of Godavari Marathwada Irrigation Development Corporation (GMIDC), said use of chemicals as evaporation retardants for irrigation projects did not produce satisfactory results in the past. “Due the wind resistance, the layer of chemical used as evaporation retardant tears away and does not reform on its own. In the wake of this, use of chemical treatment is out of the question for major irrigation projects,” he said.
Referring to outcome of certain experiments mentioned in the Integrated State Water Plan for Godavari Basin, released in November 2017, GMIDC authorities said resorting to the use of chemical covers was “unviable, uneconomical and impractical”.