METHODS TO CONTROL EVAPORATION FROM LAKES
the below recommended measures can be effective to reduce evaporation from water surfaces.
1) The storage reservoirs should have more depth and less surface area. The area or site for construction of a dam should be so chosen that a deep reservoir with minimum surface area exposed to atmosphere is formed.
2) Tall trees should be planted on the wind flowing side of the reservoir so they can act as wind breakers.
3) By spraying a chemical such as Acetyl Alcohol on water surface, a film of 0.15 microns thickness is produced on the surface. This film allows precipitation in but does not allow evaporation. This method is suitable only when velocities of wind are less and for small and medium sized reservoirs.
4) In case of ponds and lakes mechanical covering can be done, where entire water body is covered with thin polythene sheets.
5) In reservoirs outlet arrangements should be so done to let out warmer water at top than cold water from bottom.
6) De-weeding the reservoirs must be done, so that water consumed by weeds/small plants is reduced.
7) The streams and channels to be straightened so that length and in turn exposed area to atmosphere are reduced.