Improvement in Performance of A Downstream Barrage Due to A New Balancing Reservoir Upstream
Prakasam Barrage is a tail end barrage on Krishna river situated at Vijayawada in Andhra Pradesh. Entire delta irrigation is catered by this structure. The flows of about 100 TMC from the catchment between Nagarjunasagar(NSP) a upstream reservoir and Prakasam barrage and regulated releases of 52.2 TMC are to be used for this project. A balancing reservoir at Pulichintala is constructed to utilise the intermediate yield effectively and to stabilise the irrigation under Krishna delta. This paper studies the improvement of Krishna delta system due to Pulichintala. The Integrated operation of NSP and Prakasam Barrage is done without Pulichintala considering the net inflows in to NSP after ultimate development and the demands planned under NSP and Prakasam Barrage using Mike basin and excel . The Pulichintala project is then introduced and the integrated operation of the three components are done. In both cases Standard Linear operation policy adopted. However in the 2ndscenario no releases are made to Prakasam Barrage from NSP if water is available at Pulichintala. The releases from Pulichintala in the 2ndscenario and releases from NSP in the first scenario to Prakasam Barrage are worked out considering the contributions from the respective intermediate catchments namely Pulichintala to Prakasam Barrage and NSP to Prakasam Barrage respectively. The results are compared for success and June requirements. It is found that the success rate of both NSP and Prakasam barrage have improved due to Pulichintala and the demand planned could be met at 75% reliability even in the ultimate scenario. It is observed in the ultimate scenario the demand of NSP can not be met in 14 years out of 47 years without Pulichintala and this comes to 13 years out of 47 years with Pulichintala . It is observed in the ultimate scenario the demand of Krishna delta can not be met in 13 years out of 47 years without Pulichintala and this comes to 12 years out of 47 years with Pulichintala The june requirements of Prakasam barrage could be met in 41 years out of 47 years as against 33 years without Pulichintala.
Key words- Krishna delta, Nagarjunasagar, Pulichintala, reservoir performance, reliability and success rate, Balancing reservoir