There is no need for a reservoir with a huge capacity of 160 tmc under the Kaleswaram lift irrigation scheme to store water for irrigation purpose as part of the redesigned Pranahita-Chevella project, says retired Engineer-in-Chief and UN Consultant T. Hanumantha Rao.
“For irrigating the estimated 18 lakh acres of irrigated dry crops in kharif season under the project, we do not need reservoirs as available river water can go through canals to the fields as is happening in the Jawaharlal Nehru Lift Irrigation project on river Yamuna,” he said.
He, however, said for meeting the requirement of drinking water and industries, smaller reservoirs to store about 45 tmc at places where government deems fit can be constructed.
Telangana Government in its presentation during the last Legislative Assembly session on the redesigned mega Pranahita-Chevella project had said a reservoir of about 160 tmc capacity was required for Kaleswaram LI project.
‘Misconceptions’
Mr. Hanumantha Rao sought to clear the air about the necessity of reservoirs for irrigation purpose as there are different perceptions and misconceptions and his views were being interpreted differently by different people.
“The cardinal principle for deciding the need for a reservoir is this. When the water at the source is available for far less number of days than the period required for water utilisation in a crop season, a reservoir is required,” Mr. Rao, an expert in the field said in an interaction with media here on Saturday.
Palamuru-RR example
The Palamuru-Ranga Reddy lift irrigation scheme where water is available for 60 days but the utilisation period is for 120 days, one has to store water required for remaining 60 days of crop season. That scheme was rightly designed for the reservoir with a storage capacity of 72 tmcft, he explained.
However in case of Kaleswaram project, storage at Medigedda for the purpose of irrigation is not required. Godavari water is available at Medigedda for 120 days and the kharif crop period is also for 120 days and the water as it flows in canals can be utilised for irrigating the crops.
He also pointed out that no reservoirs for irrigation purpose had been provided under any lift irrigation project so far. Even for Nagarjunasagar project, many lift irrigation schemes were executed but no reservoirs were built for any of the LI schemes.
One irrigated dry crop
Interestingly he said after Independence, any irrigation project sanctioned by the Union Government took into account water required for one irrigated dry crop in the kharif season.
“GoI guidelines clearly stipulate that no provision can be made for a second crop in the same area. The priority should be to provide water to the new areas which don’t even have water for one crop,” he said.
However if government wanted to give water for second crop too under the Pranahita-Kaleswaram project to utilise water availability in Godavari, then the present pumping systems, canals, tunnels designed for the project will not be sufficient and they will have to be doubled pushing up the project cost even higher.
The present 160 tmc storage planned for 18 lakh acres of ayacut is a tall order for kharif itself. It cannot be extended for rabi without additional pump sets, canals and other structures.
“People are only thinking of constructing reservoirs but not sparing a thought on how to fill them,” he pointed out.
Available river water can go through canals to the fields as is happening with the Jawaharlal Nehru Lift Irrigation project on river Yamuna
T. Hanumantha Rao,
Retired Engineer-in-Chief.
