A concrete gravity dam, 1210 meters (3970 feet) in length and with a maximum height of 163 meters above the deepest foundation level, is under construction across river Narmada.
The dam will be the third highest concrete dam (163 meters) in India, the first two being Bhakra (226 metres) in Himachal Pradesh and Lakhwar (192 meters) in Uttar Pradesh. In terms of the volume of concrete involved for gravity dams, this dam will be ranking as the second largest in the world with an aggregate volume of 6.82 million cu.m. The first is Grand Coule Dam in USA with a total volume of 8.0 million cu.m. This dam with its spillway discharging capacity of 87,000 cumecs (30.70 lac), will be the third in the world, Gazenba (1.13 lac cumecs) in China and Tucurri (1.0 lac cumecs) in Brazil being the first two.
For chute spillway Radial gates, 7 in number and size 60' x 60' and for service spillway, 23 Radial gates of size 60' x 55' are to be provided to negotiate the design flood. 10 number of temporary construction sluices, each of size 2.15 m x 2.75 m. are provided in the boby of the spillway at RL 18 m. Another set of 4 permanent river sluices are provided at RL 53.0 m. The lower sluices were closed in February, 1994.
The design of the dam allows for a horizontal seismic coefficient of 0.125g and it also covers an additional risk due to reservoir induced seism city. Most sophisticated seismological instruments for monitoring and evaluation of the stresses in the body of the dam as whell as the effect on the periphery of the reservoir are under installation.
||Length of main concrete gravity dam
||Maximum height above deepest foundation level
||Top R.L. of dam.
||Catchments area of river above dam site
||88,000 Sq. km
||Live storage capacity 0.58M.Ha.m
||Length of reservoir
|7 Nos. 60' x 60'
23 Nos. 60' x 55'
(30 lakh cusecs)
Sardar Sarovar Reservoir
The Full Reservoir Level (FRL) of the Sardar Sarovar Dam is fixed at RL 138.68 metres (455 feet). The Maximum Water Level is 140.21 metres (460 feet.) while minimum draw down level is 110.64 metres (363 feet.). The normal tail water level is 25.91 metres (85 feet.).
The gross storage capacity of the reservoir is 0.95 M. ha.m. (7.7 MAF) while live storage capacity is 0.58 M.ha.m. (4.75 MAF). The dead storage capacity below minimum draw down level is 0.37 M. ha. m. (2.97 MAF). The reservoir would occupy an area of 37,000 ha. and would have a linear stretch of 214 kilometer of water and an average width of 1.77 kilometer.
The submergence at Full Reservoir Level (FRL) is 37,690 ha. (86,088 acres), which comprises 11,279 ha. agricultural land, 13,542 ha. forests and 12,869 ha. river bed and waste land. In all 245 villages of the three states viz. 193 Villages of Madhya Pradesh, 33 villages of Maharashtra and 19 villages of Gujarat are affected. Only 3 villages of Gujarat are fully affected, while the remaining 242 villages are partly affected. In Madhya Pradesh, out of 193 villages, more than 10% agricultural land will be submerged only in 79 villages, in 89 villages less than 10% agricultural land or only houses will be submerged under FRL, due to back water of 1 in 100 years flood. In 25 villages, only Government waste land will be submerged.