| Kakki Dam | |
| Image Caption: | View of Kakki dam and reservoir |
| Dam Crosses: | Kakki river |
| Res Name: | Kakki Reservoir |
| Location: | Pathanamthitta, Kerala |
| Operator: | Kerala State Electricity Board |
| Res Catchment: | Kakki Dam: Upper Moozhiyar: |
| Plant Turbines: | 2 x 60 MW & 4 x 55 MW (Pelton-type) |
| Plant Capacity: | 340 |
| Plant Annual Gen: | 1338 MU |
| Location Map: | India Kerala#India |
| Coordinates: | 9.325°N 77.1422°W |
| Website: | Official website |
| Country: | India |
| Purpose: | P |
| Status: | O |
| Plant Name: | Sabarigiri Power Station |
| Plant Operator: | Kerala State Electricity Board |
| Plant Coordinates: | 9.31°N 77.0728°W |
| Spillway Count: | No spillway |
| Dam Type: | G |
| Extra: | Spillway provided at Anathode Flanking Dam |
Kakki Dam is a concrete gravity dam built on the Kakki river, a tributary of the Pampa river in the Ranni forest in the Seethathodu panchayat of Pathanamthitta district in Kerala, India. The dam is located in a forested area adjacent to the Periyar National Park. It was built in 1966[1] as part of the Sabarigiri Hydroelectric Project. The water sources of the dam are from the Pampa dam and the Kakki river. The Sabarigiri project envisaged creation of two reservoirs which are Pamba and Kakki reservoirs and connecting these together to form a single source of water. The water from Pamba reservoir is connected to the Kakki reservoir through an underground tunnel of length 3.21 km. The intake of the Sabarigiri Powerhouse is from Kakki reservoir.[2] The dam is long and high and is located at an elevation of above sea level. The release flows through Ranni, Konni, Kozhencherry, Thiruvalla, Chengannur, Kuttanadu, Mavelikara and Karthikappally taluks [3] before emptying into the Vembanad lake.
See main article: Anathode dam. A flanking Dam for the Kakki reservoir is located at Anathode, about 2.5 miles northeast of Kakki dam, where a low saddle existed. The flanking dam is built to increase the capacity of the Kakki reservoir and to host the spill way. The dam has a height of 170 feet above the foundation and a length of 1500 feet including the spill way.[4] Spillways are 4 Numbers with radial gates of size 12.8 x 6.1 meters
The Project plan was to create a reservoir by impounding Pampa River and another Reservoir by impounding Kakki River and connecting both the reservoirs by means of a tunnel to form a connected reservoir. Preliminary works and investigation was done in 1958 and the dam construction was started in 1960. Initial surveillance and mapping was completed in 1961. The housing colonies for the staffs were built after the project was conceived. The work of Pamba Dam started in 1962. The anathode dam was constructed along with Pamba dam. The concrete Kakki Dam was finished in 1966. The tunnel to connect the two reservoirs was built and was lined by concrete. The power house was built with American aid. In April 1966 two generators were commissioned. It was inaugurated in 1967 August 28 by V. V. Giri the deputy president of India.
The whole work for the construction of Kakki dam was completely mechanised.
The original proposal was to construct an arch dam, but this was changed later to Masonry Straight dam. Tenders were invited in December 1961 and the contract was given to Hindustan Construction Company in Bombay in October 1962. Dam was scheduled to be completed by 1965 as per agreement but the works were completed only in 1966.[6]
In 1954-56 a road was constructed from Vallakadavu to Kakki. It was modernised in 1961. In the same year a staff colony consisting of 250 houses was built at Anathodu . A contractors' colony consisting of 300 houses, was constructed by 1963. A provision store was opened at Anathode in 1962. The machineries of the contractors H.C.C. had to be transported from the a dam site in Uttar Pradesh where they had recently completed a dam construction.
The foundation excavation was started by HCC during 1961–62. Weak zones were found in actual excavation and were treated accordingly. The excavation work was completed by March 1964.
In the original estimate the dam was to be made with rubble in cement, But later the dam was converted into completely cement. The concreting works of the Kakki dam was started on 16 January 1964. Due to the deeper foundation and the height of the dam was increased by 10 feet and the quantity of concrete increased to 256 lakhs cubic feet.[7] The height of the elevator also had to be increased in accordance with the new requirements.
During the Monsoon Seasons, discharging of water had to be done and it was carried out by keeping the Elevator no. 9 as spilling block which necessitated formation of a toe of the spilling blocks.
The emergency gates and hollow jet valves were obtained from Pacific Cost Engineering Company in USA. The construction of valve house was completed in 1965 and the installation of the emergency gate and hollow jet valves were completed by the end of September 1966.
The spill way which regulate flood discharge was 4 in numbers. The radial gates to separate hosting accessories were supplied by Pacific Coast Engineering Company, California. According to the agreement the contractor was in charge of the actual erection of the gates and it was to be done after the civil works but due to some delay in the concreting of the hoist bridge, the installation work was carried out later with special arrangements.
The Pamba and the Kakki reservoirs of the Sabarigiri hydroelectric project have been connected by an interconnecting tunnel which is 10450 meters long and is lined with cement concrete. The face excavation was started in 1961 and took 3 months. The tunnelling was started 1n 1963 and was completed in 25 months.
See main article: Kakki Reservoir. Kakki reservoir was created when Kakki and its flanking dam, Anathode dams were built. Full reservoir level (FRL) is 981.45 meters above sea level.[8] The reservoir, which is also a tourist spot, is in the Ranni reserve forest close to the Western Ghats.[9]
Sabarigiri Power Station was commissioned during 1966 -67 with six generators having vertical shaft pelton turbine as the prime mover. After power generation, water from the power station is released to the Moozhiyar reservoir. There are 114 employees in the project who works in three shifts.[12]
This is located on the left bank of the reservoir upstream of the Kakki dam. It consisted of a shaft with a length of 237 inches. The flow of water is regulated by a vertical lift gate. The arrangements have been built on a hoist platform. Trash rack arrangements are also provided. A set of 3 high pressure surface penstocks about 2.611 km long each bifurcating just above the generating station from where 6 branches are taken to the power house.[13]