Koyna dam

detailed information on KOYANA HYDROELECTRIC PROJECT that creates enormous renewable energy

1. koyana Dam कोयना धरण

2. The koyana Dam is one of the largest dams in Maharashtra , India . It is a rubble-concrete dam constructed on koyana River which rises in Mahabaleshwar , a hillstation in Sahyadri ranges. It is located in koyana Nagar , Satara district , nestled in the Western Ghats on the state highway between Chiplun and Karad . Introduction

3. The main purpose of dam is hydroelectricity with some irrigation . koyana Hydroelectric Project is the largest completed hydroelectric power plant in India having a total installed capacity of 1,920 MW . Due to its electricity generating potential koyana river is considered as the 'life line of Maharashtra. Introduction

4. In the early 20th century, there was a survey of the koyana River as hydro-electric source by the Tata Group . The 1928 financial crisis caused the project to be shelved . After the independence of India , it was taken over by the Government of Maharashtra . In 1951 koyana Dam division started to look into the project. The project was approved in 1953 and work commenced in early 1954 and completed in 1962. History

5. Dam and spillways Type of dam- Rubble-concrete dam Impounds- Koyna River Height- 103.2 m (339 ft) Length- 807.2 m (2,648 ft) Reservoir Creates - Shivajisagar Lake Total capacity - 2,797,400,000 m 3 (2,267,900  acre·ft ) Surface area- 891.78 km 2 (344 sq mi) Features

6. The spillway of the dam is located at the center. It has 6 radial gates . The dam plays a vital role of flood controlling in monsoon season . Description

7. The catchment area dams the koyana river and forms the Shivajisagar Lake which is approximately 50 km (31 mi) in length. It is one of the largest civil engineering projects commissioned after Indian independence. The koyana hydro-electric project is run by the Maharashtra State Electricity Board . Description

8. The dam has withstood many earthquakes in the recent past, including the devastating 1967 koyananagar earthquake . resulting in the dam developing some cracks . The proposal is to drill up to 7  km bore hole and study the physical, geological and chemical processes and properties of the reservoir triggered earthquake zone in real time. It would be an international project to be led by Indian scientists . Challenges of NATURE

9. In 1973 the non-overflow portion of the dam was strengthened, followed by strengthening the spillway section in 2006. Also internal holes were drilled to relieve the hydrostatic pressures in the body of the dam. Indian scientific establishment has formulated an ambitious project to drill a deep borehole in the region and intensely study the earthquake activity. Now the dam is expected to be safe against any future earthquake even of more intensity than that of 1967. Repairs of dam

10. The koyana Hydroelectric Project is the largest completed hydroelectric power plant in India . It is a complex project with four dams including the largest dam on the koyana River known as the koyana Dam hence the name koyana Hydroelectric Project. The project site is in Satara district near Patan . The village Helwak near the dam was later known as koyananagar . koyana Hydroelectric Project

11. The total capacity of the project is 1,960 MW . The project consists of four stages of power generation. All the generators are located in underground powerhouses excavated deep inside the mountains of the Western Ghats . A dam foot powerhouse also contributes to the electricity generation. The project takes advantage of the height of Western Ghats. Thus a very large hydraulic head is available over a very short distance. koyana Hydroelectric Project

12. 1st and 2nd stages share same powerhouse with total eight Pelton turbine units. Stage I and II

13. Capacity- four turbines having of 65 MW each for 1st stage and 75 MW each for 2nd stage. The water from The shivajisagar reservoir is taken through an intake structure known as Navja tower near village of Navja into the head race tunnel. Then it travels towards the surge tank . It is further divided into four pressure shafts which run vertically downward delivering water to the turbines. Then the water is discharged into the tail race tunnel.

14. A dam foot powerhouse was also constructed which is used to generate electricity by the water which is discharged from the koyana Dam for irrigation purpose. It has two Francis turbine units of 20 MW each. This powerhouse is run according to the irrigation requirements of the downstream areas. The combined installed capacity of the two stages and the dam foot powerhouse is 600 MW. Stage I and II

15. It was observed that the water still had a hydraulic head of about 120 m which could be used. To use this head, the Kolkewadi Dam was constructed at this location. It forms a balancing reservoir and maintains the head. This dam impounds the tail race water from Stage I and II. This water is drawn through penstocks and electricity is generated by four Francis turbine units with a capacity of 80 MW each. The tail race water from these stages then flows through a channel and joins the Arabian Sea near Chiplun . The installed generating capacity of this stage is 320 MW Stage III

16. Later in the 1980s, the electricity demand of the Maharashtra increased tremendously resulting in inadequate power supply. The Planning Commission accorded approval to Stage IV with installation capacity of 4 × 250 MW . Thus , one more stage called Stage IV was introduced, thus converting the koyana Power Station into a peaking power station complex with load factor of about 18.7%. This scheme also draws water from the existing shivajisagar reservoir same as Stages I and II. Stage IV

17. Lake tapping - nonconventional intake system was created by piercing the lake from the bottom by blasting the rock plug using dynamite . This double lake tapping process was the first of its kind in Asia . Stage IV

18. The water in head race tunnel is directly drawn from the reservoir and delivered to the head surge tank . The four huge Francis turbine units of 250 MW each generate electricity and tail race water is taken into the Kolkewadi Dam reservoir through tail race tunnel. A revolutionary gas insulated switchgear system is used in the underground powerhouse of this stage. The installed capacity of this stage alone is 1000 MW. This stage is mostly used to cater for the peak hour demands of the electric grid .

19. Stage Unit number Installed capacity ( MW ) Date of commissioning Status Stage 1 70 1962 May Running Stage I 2 70 1962 August Running Stage I 3 70 1963 January Running Stage I 4 70 1963 February Running Stage II 5 80 1967 June Running Stage II 6 80 1966 November Running Stage II 7 80 1966 June Running Stage II 8 80 1966 March Running

20. StageIII 9 80 1975 July Running StageIII 10 80 1976 January Running StageIII 11 80 1977 May Running StageIII 12 80 1977 Running StageIV 13 250 1981 Running StageIV 14 250 1981 Running Stage IV 15 250 1981 Running Stage IV 16 250 1981 Running

21. To utilize more water from the shivajisagar reservoir, another dam foot powerhouse is being constructed on the left bank of the dam. This powerhouse will employ a pumped storage scheme. Also lake tapping is proposed for the intake system. Future plans

22. Koyana Wildlife Sanctuary- has dense forests with three major sections, Vasota , Maharkhor and Indavli Met The sanctuary is endowed with natural protective boundaries Some of the endangered species of trees found in the sanctuary Vasota Fort lies deep in the forest and is located at a height of 1,120 m (3,675 ft) above sea level. The legend states that the fort was constructed by Malwa king Raja Bhoja in 1170. Tourism

23. On 10 April 1960, the then Prime Minister of India Jawaharlal Nehru visited koyana Project. This park is a major attraction for tourists. An upstream side view of dam is visible from this garden. There is an auditorium named ' Yashogatha ' (meaning: story of success) which reviles a small element of the tremendous efforts taken by the engineers and workers associated with project. Nehru Memorial park

24. Some beautiful falls are generated in the monsoon season . The largest of them is the Ozarde falls near Navaja village 10 km from koyana . Ozarde falls

25. Created by- Madhusudan Dilip Yadav