TheSrisailam Damis constructed across theKrishna RiverinNandyal district,Andhra PradeshandNagarkurnool district,TelangananearSrisailamtemple town and is the2nd largest capacityworkinghydroelectricstation in India.[3]
| Srisailam Dam | |
|---|---|
 | |
  Location of Srisailam Dam in Andhra Pradesh | |
| Location | Sri Sailam,Nandyal district,Andhra Pradesh,IndiaDomalapenta,Nagarkurnool district,Telangana,India |
| Coordinates | 16°05′13″N78°53′50″E/ 16.08694°N 78.89722°E |
| Purpose | Hydroelectric,Irrigation&Water supply |
| Construction began | 1960 |
| Opening date | 1981 |
| Construction cost | ₹10 billion[citation needed] |
| Owner(s) | Government of Andhra Pradesh |
| Dam and spillways | |
| Type of dam | Gravity&Masonry dam |
| Impounds | Krishna River |
| Height | 145.10 m (476 ft)[1][2] |
| Length | 512 m (1,680 ft) |
| Spillway capacity | 38369cumecs |
| Reservoir | |
| Creates | Srisailam Reservoir (Neelam Sanjeevareddy Sagar) |
| Total capacity | 216Tmcft |
| Catchment area | 206,040 km2(79,550 sq mi) |
| Surface area | 616 km2(238 sq mi) |
| Power Station | |
| Operator(s) | APGENCO(right bank) andTGGENCO(left bank) |
| Turbines | 6 × 150 MW (200,000 hp) reversibleFrancis-type(left bank) 7 × 110 MW (150,000 hp) Francis type (right bank) |
| Installed capacity | 1,670 MW (2,240,000 hp) |
The dam was constructed in a deep gorge in theNallamala Hillsin between Nandyal and Nagarkurnool districts, 300 m (980 ft) above sea level. It is 512 m (1,680 ft) long, 145 metres (476 ft) maximum height and has12 radialcrest gates. It has a reservoir of 616 square kilometres (238 sq mi). The project has an estimated live capacity to hold 178.74Tmcftat its full reservoir level of 885 feet (270 m)MSL.Its gross storage capacity is 6.116 cubic km (216 tmc ft). The minimum draw-down level (MDDL) of the reservoir is at 705 feet (215 m) MSL from its river sluice gates, and corresponding dead storage is 3.42 Tmcft.[4]The left bank underground power station houses6 ×150 megawatts (200,000 hp) reversibleFrancis-pump turbinesforpumped-storageoperation (each turbine can pump 200cumecs) and the right bank semi-underground power station houses7 ×110 megawatts (150,000 hp) Francis-turbine generators.
Tail pond dam/weir located 14 km downstream of Srisailam dam is under advanced stage of construction to hold the water released by the hydro turbines and later pump back into the Srisailam reservoir by operating the turbines in pump mode.[5]The weir portion got breached in November 2015 unable to withstand the normal water release from thehydropowerstations.[6]Tail pond weir was completed during the year 2017 and pumping mode operation is being done even when the downstreamNagarjuna Sagar reservoirwater level is below 531.5 feet (162 m) MSL. The tail pond has nearly 1 tmcft live storage capacity.[7]
History
editThe Srisailam project began in 1960, Initially only as a power project. After several delays, the main dam was finally completed twenty years later in 1980 July 26.[citation needed]In the meantime the project was converted into a multipurpose facility with a generating capacity of 770 megawatts (1,030,000 hp) by its second stage which was completed in 1987.[citation needed]The dam is to provide water for an estimated 2,000 square kilometres (770 sq mi). Under the right bank branch canal 790 square kilometres (310 sq mi) in Kurnool and Kadapa districts will have assured irrigation. From the initial modest estimate of₹38.47 crorefor a power project the total cost of the multipurpose project was estimated to cross₹1000 crorein its enlarged form. The dam has alone cost₹404 croretogether with the installation of four generating sets of110 MWeach. The right bank branch canal is estimated to cost₹449 croreand the initial investment of₹140 crorehas been provided by the World Bank. The projected cost-benefit ratio of the project has been worked out at 1:1.91 at 10% interest on capital outlay.[citation needed].In 1998 a coffer dam was over topped by flooding. The power house required repairs and did not generate power for a year. On 2 October 2009, Srisailam dam experienced a record inflow which threatened the dam.[8]It was built under the engineering leadership ofKanuri Lakshmana Rao.
Irrigation
editSrisailam right main canal (SRMC) is constructed with 44,000cusecscapacity at Srisailam reservoir level of 269.22 metres (883 ft)MSLto feedVeligodu reservoir(16.95 tmcft),Brahmamsagar Reservoir(17.74 tmcft), Alaganoor reservoir (2.97 tmcft), Gorakallu reservoir (12.44 tmcft), Owk reservoir (4.15 tmcft),Gandikota Reservoir(26.86 tmcft),Mylavaram reservoir(9.98 tmcft),Somasila reservoir(78 tmcft) andKandeleru reservoir(68 tmcft) with nearly 235 Tmcft total storage capacity.[9]This canal also supplies water toTelugu Ganga projectwhich supplies Krishna river water toChennaicity for its drinking purpose.[10]This main canal by feeding water toK. C. Canal,Srisailam right bank canal, Telugu Ganga canal andGaleru Nagari canalirrigates vast area inKurnool,Kadapa,ChittoorandNellore districts.
Handri-Neevalift canal by drawing water from the Srisailam reservoir, which supplies drinking water in all the districts ofRayalaseema.Veligonda reservoirreceives water by gravity through tunnels to irrigate lands in Nellore, Kadapa andPrakasam districts.Kalwakurthy lift irrigation schemeby drawing water from the Srisailam reservoir, supplies irrigation water inMahbubnagarandNalgonda districts
Srisailam left bank canalwill receive water by gravity through tunnels to irrigate lands inNalgonda district.Tunnel work is not complete and the required water has been provided to most of the project area by lifting water from the downstream Nagarjuna Sagar reservoir.
Dam Maintenance and Safety
editSystematic Neglect and absence of diversion of funds is evident in maintenance of the dam and lack of any modernization attempts of the Powerhouse. The officers report a shortage of maintenance staff.[11]
Safety concerns to the 2nd largest Hydroelectric project in the country have been raised over the years[12][13]and have been assessed false subsequently.[14]In 2009, the dam, designed for a maximum flood of 19 lakh cusecs, endured a flood of 25.5 lakh cusecs. According to a survey conducted in the summer of 2018, the scouring resulted in the formation of a huge pit in the apron downstream the dam. And a structure protecting the ‘toe’ and foundation of the main dam has weakened. Efforts are not yet made to repair and maintain the dam.[15]
Power generation optimization
edit
At present, the initial inflows intoSrisailamreservoir are stored excessively without being used for power generation. The flood water fills the remaining empty Srisailam reservoir quickly and most of the flood water overflows into the downstreamNagarjunasagarreservoir without being used for power generation.[16]The endeavor shall be to fill the Nagarjuna Sagar reservoir fully with the uniform water released through the power generating units.
The existing right bank power station (770 MW) can be converted intopumped storage hydroelectric power (PSHP)to operate in pumping mode when the downstreamNagarjuna Sagar reservoirlevel is above 560 feet (171 m) MSL. The PSHP can be used for energy storage purposes on daily basis and to transfer Godavari water to the Srisailam reservoir during drought years. Alternately, the tunnel of the existing power station can be used for a new PSHP station to pump water from the Nagarjuna Sagar reservoir to the Srisailam reservoir.
Pumped storage hydropower potential
editSrisailam reservoir, serving as lower level reservoir, has potential to install nearly 77,000 MWhigh head pumped storage hydroelectric plantson its right side.
See also
edit
- Krishna Water Disputes Tribunal
- List of power stations in India
- List of dams and reservoirs in India
- List of hydroelectric power station failures
- Nagarjuna Sagar tail pond
References
edit- ^"India: National Register of Large Dams 2009"(PDF).Central Water Commission. Archived fromthe original(PDF)on 21 July 2011.Retrieved10 July2011.
- ^Jauhari, V.P. (2005).Sustaining river linking.New Delhi, India: Mittal Publications. p. 84.ISBN817099991X.
- ^"Srisailam (N.S.R.S.P) Dam D00557".Retrieved22 September2015.
- ^"Neelam Sanjeeva Reddy Srisailam Project".Archived fromthe originalon 25 September 2017.Retrieved22 September2017.
- ^"Srisailam Tail pond Dam".Archived fromthe originalon 11 July 2018.Retrieved22 December2015.
- ^"Srisailam Tail pond Dam leaked".YouTube.Archived fromthe originalon 11 March 2016.Retrieved22 December2015.
- ^"Srisailam dam tail pond level and storage capacity"(PDF).Retrieved22 September2015.
- ^"Managing historic flood in the Krishna river basin in the year 2009".Archived fromthe originalon 26 October 2017.Retrieved21 January2012.
- ^"AP Reservoirs real time data".Retrieved22 July2018.
- ^"Telugu Ganga project".Retrieved22 September2015.
- ^Rao, G. Venkataramana (20 November 2019)."Srisailam dam in need of urgent maintenance".The Hindu.ISSN0971-751X.Retrieved23 July2020.
- ^Rao, G. Venkataramana (16 November 2019)."Experts worried about safety of Srisailam dam".The Hindu.ISSN0971-751X.Retrieved22 July2020.
- ^Pulipaka, AuthorBalu."Srisailam dam safety under lens".Telangana Today.Retrieved22 July2020.
- ^Staff Reporter (22 November 2019)."No threat to Srisailam dam, asserts Minister".The Hindu.ISSN0971-751X.Retrieved22 July2020.
- ^Rao, G. Venkataramana (16 November 2019)."Experts worried about safety of Srisailam dam".The Hindu.ISSN0971-751X.Retrieved22 July2020.
- ^Optimisation of power generation from Srisailam Hydroelectric Power Station