Nagarjuna Sagar tail pond
Nagarjuna Sagar tail pond is a multipurpose reservoir located 21 km downstream from the Nagarjuna Sagar Dam across the Krishna River near Satrasala in Guntur district. Its gross water storage capacity is 6 Tmcft. The reservoir water spread area extends up to the toe of the Nagarjuna Sagar dam. The project is under construction and expected to be completed by July 2014.
Hydro electricity generation
Two units of 25 MW each hydro power generation units are under construction by APGENCO to utilize the head available across the dam from the river flood water and the water released to Prakasam Barrage requirements.
Peaking power generation
Presently, the 700 MW reversible hydro turbines (7 x 100 MW) located at the toe of Nagarjuna Sagar Dam are unable to operate in pumping mode due to non availability of tail pond for storing the released water during the power generation mode. With the completion of tail pond, surplus electricity from the electricity grid would be used for pumping the water back to the Nagarjuna Sagar reservoir and recycled for meeting peaking load on daily basis. Thus surplus electricity is consumed when it is available and used to meet the peak electricity requirements without letting the water out of the Nagarjuna Sagar tail pond. 700 MW peaking power for eight hours duration can be met from the one Tmcft of live storage water capacity available in the tail pond.
200 Tmcft surplus water annually from the Godavari River is planned to be fed into this tail pond by the Dummugudem Lift Irrigation Scheme which is under execution. The water transferred to this tail pond will be pumped to the upstream 410 Tmcft gross water storage capacity Nagarjuna Sagar reservoir to feed its right and left bank canals. Thus Nagarjuna Sagar reservoir need not receive the water supply from the upstream Srisailam reservoir. As the tail water level (48.33 m MSL) of this dam is below the full reservoir level (53.34 m MSL) of the downstream Pulichintala dam, surplus water in Pulichinthala reservoir can be pumped by envisaging pumped storage units from Pulichinthala reservoir to Nagarjunasagar reservoir via this pond. The retained water in the Srisailam reservoir would be used for upstream water uses from Jurala and Srisailam reservoirs for irrigation needs in uplands of Telangana and Rayalaseema regions. The water from the Nagarjuna Sagar reservoir can also be pumped to the Srisailam reservoir by Srisailam left bank hydro electric power station (900 MW) in pumping mode in case of severe drought in Krishna river basin. Koilsagar lift irrigation project (near ), Rajiv Bheema lift irrigation project, Nettampadu lift irrigation project (near ), Kalwakurthy lift irrigation scheme, Srisailam Left Bank Canal, Telugu Ganga irrigation project, Handri Neeva lift irrigation project, Galeru Nagari irrigation project, Veligonda irrigation project etc. which are in advanced stage of construction, are depending on the Krishna river water available at Jurala / Srisailam dams.
A lift canal from the Krishna river (Pulichintala dam will be executed to feed Godavari water diverted from Polavaram to some of the existing command area (situated below 60 m MSL) under Nagarjuna Sagar right bank canal to facilitate extension of Nagarjuna Sagar right bank canal connecting to Kandaleru feeder canal / Somasila reservoir.at 20 m MSL) downstream of
Dummugudem to Nagarjuna Sagar tail pond link canal is entirely located in Telangana region and needs to be routed through high lands which necessitate more pumping head. An alternative link canal to Nagarjuna Sagar tail pond from Polavaram dam is also economically feasible to transfer Godavari water. This link canal passes entirely through the coastal Andhra Pradesh region only.
Joint projects with Karnataka
The Rajolibanda barrage is not receiving adequate continuous flows due to excessive water utilization in its catchment area in Karnataka. It would be a permanent solution to connect the upstream catchment area (near at 475 m MSL) via 20 km long tunnel with the Narayanpur reservoir which is located across the adjacent Krishna River. It would also provide additional water to bring more area under irrigation in uplands of Raichur & Mahboobnagar districts and low lands of Kurnool district. Reliable Krishna river water can be supplied instead of unreliable Tungabhadra river water to the existing Tungabhadra Left bank canal in Raichur district, the existing Rajolibanda left bank canal and the existing 150 years old K. C. Canal. In addition to taking up Rajolibanda right bank canal construction, a new barrage /weir ( ) would be constructed across the Tungabhadra river located in the upstream of Rajolibanda barrage to divert the augmented Krishna river water for the additional irrigation in Kurnool district. Lift irrigation would also be envisaged to feed Tungabhadra low level right bank canal in Kurnool district from this new barrage. Thus substantial Tungabhadra reservoir water would be saved for utilization in upstream new projects and reliable water supply is ensured to existing projects. Refer to Google Earth data for more geographical information.
A new barrage (FRL 349 m MSL) across the Krishna river just downstream of Bhima river confluence point on the common border of Karnataka and Andhra Pradesh states (near ), can also be taken up to supply Krishna river water to the western most parts of Mahbubnagar district by lift irrigation.
Ultimately, 500 tmcft water is to be transferred annually from the Godavari river to this pond for meeting various water needs in Andhra Pradesh. Thus Nagarjuna Sagar tail pond will play pivotal role to put to use the water from the Godavari River in all regions of the Andhra Pradesh state.
- "Nagarjuna Sagar tail-pond dam likely to benefit Krishna delta". Retrieved 11 May 2013.
- "Nagarjuna Sagar tail pond dam progress report". Retrieved 11 May 2013.
- "Blue Print for Godavari River Water Utilization in Andhra Pradesh". Retrieved 11 May 2013.
- "Krishna River Water Sharing Accord". Retrieved 11 May 2013.