The Prakasam Barrage, the last point where water in the Krishna is impounded for the irrigation of 13.5 lakh acres in Prakasam, Guntur, Krishna and West Godavari districts of Andhra Pradesh, turned 60 this year. It is also a watershed year for the barrage in the sense that it did not receive a single drop of surplus water. All received water could be diverted into the canals. Krishna Delta farmers, who enjoy the primary riparian right, are denied of water for cultivation.
Prakasam Barrage Authorities are usually forced to release at least a few tmcft of floodwater by lifting the crest gates to avoid inundation of low-lying or lanka (island) areas along the banks of river upstream of the barrage.
- Cumulative capacity of major dams across Krishna: 974 tmcft
- Cumulative capacity of major dams across Godavari: 296 tmcft.
- Total water received at Prakasam barrage this season (from June 2017): 138.48 tmcft
- Surplus water at Prakasam Barrage this season: zero tmcft
- Surplus or water at Dowlaiwaram Barrage this season: 1022 tmcft
- Official number of major and medium projects on Krishna River: 210
- Projects completed: 135
- Ongoing projects: 75
Barrage authorities had to release a minimum 2.28 tmcft in 2002-03, the next year they had to release 6.29 tmcft and in 2015-16 they discharged 9.26 tmcft to maintain the mandatory lelel of 12 feet at the barrage.
But the inflows into Prakasam Barrage have not always been so paltry. A surplus of 3,162.3 tmcft had to be discharged from Prakasam Barrage during 1961-62. A surplus of over 2,000 tmcft was recorded every year till 1964-65 and after, that the surplus gradually came down.
Former Irrigation Board member and an authority on reservoirs, canals and tanks in Andhra Pradesh Yerneni Nagendranath said that earlier all water in Krishna River came to Prakasam Barrage because there were no dams. The first of the big dams, the Nagarjuna Sagar, was completed only in 1967. Besides the major and medium irrigation projects on the Krishna, several unauthorised lift irrigation schemes and road barrages have come up in Maharashtra and Karnataka.
The building of Almatti, followed by the increase of its capacity was the last straw that broke the camel’s back. The Krishna Delta, which enjoyed the first riparian rights for Krishna water, was left in the lurch, he said.
Mr. Nagendranath was one among several experts on water resources who predicted that Krishna Delta would to be converted into a desert if the trend continued.
Polavaram
While the completion of Polavaram project that should link the Godavari to the Krishna was getting inordinately delayed, the Andhra Pradesh government came up with a temporary solution to save the Krishna Delta by establishing the Pattiseema Lift Irrigation Scheme with the capacity to supply 100 tmcft a year. The Godavari, which still has a relatively less number of major projects on it, discharges an average 3,000 tmcft an year into the sea.