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Somasila Reservoir

This is an operational major project on Pennar River in Andhra Pradesh for stabilizing irrigation in Pennar delta. The dam is located near Somasila Village, Atmakur Taluk of Nellore District at Latitude 14o 29'15" N and Longitude 79o 18' 25" E. Catchment area at dam site is 50,492.5 km2. It is an earth and rockfill + masonry and concrete dam whose maximum height above deepest foundation level is 38 m. Somasila has also been integrated as a component of the Telugu Ganga canal project which is proposed to carry water from Srisailam to Chennai city and provide irrigation benefits to the en-route areas. The gross storage capacity at FRL 100.58 m and live storage capacity of the reservoir are 2,210.00 MCM and 1,994.00 MCM respectively. At the maximum water level of 101.80 m the storage capacity is 2,483 MCM and at dead storage level of 82.30 m, it is 214 MCM. At FRL, the reservoir water spread area is 212.28 km2. The designed annual irrigation from the dam is 44.00 Million sq. meter. The irrigation and water supply demand from the dam is 1,453 and 409 Mm3 respectively. The annual volume reliability for irrigation and water supply is 0.533 and 0.917 respectively.

 

An ogee type spillway, 236.21 m with crest level at 86.868 m, has been provided to dispose flood waters. The spillway has 12 radial gates, 15.24 m × 13.72 m and the maximum discharging capacity at FRL and MWL is 19,680 cumec and 22,375 cumec respectively. Table 15.24 gives some other details about the project.

Some features of Somasila Project

General data

Ayacut

167,670 ha (414,000 acres)

Kharif

111,375 ha (275,000 acres)

Rabi

56,295 ha (139,000 acres)

Culturable Command Area (CCA)

1.64 lakh ha (4.05 lakh acres)

Proposed utilization under the project

Kharif (Stabilization of Existing command)

996 Mm3  (35.15 TMC)

Rabi       a) Dry

292 Mm3 (10.308 TMC)

              b) Wet

 87 Mm3 (3.09 TMC)

Total

1375 Mm3 (48.548 TMC)

Main canal

North feeder channel

South feeder channel

Kavali canal

Length

72.92 km

76.2 km

67.5 km

FSL at Head

80.92 m

85.38 m

33.84 m

Maximum discharging capacity

10.76 cumec

10.48 cumec

28.32 cumec

Source:  GoAP (1984).

 

 

Sathanur Reservoir

Sathanur reservoir was created in 1957 on the Pennar River at Sathanur village in Tiruvannamalai Sambuvarayar district. The reservoir has a capacity of 228.91 million m3 at FRL of 222.2 m and a mean depth of 11.4 m. It covers 2,010 ha area at the FRL.