Effect of Riser Height on Reducing Evaporation Losses from Dugout Type Farm Pond in Saline Tract Area

Harvesting rain water and reusing it for life saving irrigation has become an urgent need of the hour for improving the production potential of dry farming areas under changing rainfall situation. To improve the drought prone situation in drought affected districts of Vidarbha, number of dug out type ponds (water storage structures) for harvesting of excess rain water are constructed on farmers field. The harvested water is being used for providing life saving irrigation to dryland crops by lifting and applying to the fields. To minimize the evaporation losses from such small water harvesting structures in semi-arid regions scientist world over, have tried several types of anti-evaporants such as floating sheet cover of plastic membrane, polystyrene sheet, foamed wax blocks, plant residue, oil mulches, polyethylene oxides, gum mixtures and fatty alcohols. There was not much success with these attempts. As yet, an efficient, economical and durable evaporation suppressant has not emerged from the research which can be used widely. Since large number of dug out type farm ponds (120) are constructed in Ghusar Village of Akola taluka with varying sizes, the present study was planned to evaluate effect of pond riser height on wind velocity control which is the prime factor in deciding the quantum evaporation losses. For quantifying the effect of height of pond riser wall (embankment height) on evaporation losses from it, four square size unlined dug out type ponds (30 m X 30 m) in Ghusar village were selected. The selected ponds were having on an average 0.58 m, 1.70 m, 2.15 m and 2.59 m riser heights which will indicate its impact in controlling wind speed inside the pond and indirectly reducing water evaporation. Water levels in the ponds were monitored regularly from October onwards. The effect of riser height on reducing evaporation losses from dugout type farm pond was found to be highly significant. The field data recorded during October to December 2010 indicated 13.9, 22.18 and 31.05 per cent saving in water loss due to evaporation from dugout type farm ponds with 1.71 m, 2.17 m and 2.59 m riser height over that of 0.58 m riser height.