Introduction

The Kalai-II Hydroelectric Project is located in Hawai, Anjaw District, Arunachal Pradesh. The project site is approximately 325 km from Tinsukia, the nearest railway station, and 362 km from Dibrugarh, the nearest airport. 

The Project is a run-of-river scheme with pondage involving construction of 198 m high Concrete Gravity Dam on the Lohit River, a tributary of the Brahmaputra. 

The installed capacity of the Project is 1200 MW comprising of 06 generating units of 190 MW each and 1 unit of 60 MW. 

Upon completion, the project is expected to generate annual energy of 4,852.95 MUs, corresponding to 90% dependable year at 95% plant availability, with an average peaking of more than 3 hours during the lean season (November–March).

 

The EIA-EMP of the project has been prepared during 2024-2025 through consultant agency M/s WAPCOS India Ltd. in line with Terms of Reference (ToR) accorded by MoEF&CC. GoI. The Public Hearing for the project got conducted successfully during August 2025, and the Environmental Clearance (EC) of the project has been recommended by the Expert Appraisal Committee (EAC). EC is expected shortly.

 

Statutory Clearance: Environment Clearance granted by MoEF&CC for Kalai-II HEP

S.No.FeatureDetails
1.LocationOn Lohit river, Anjaw/ Hawai District, Arunachal Pradesh
Nearest Airport: Dibrugarh (Assam)
2.Latitude (Dam)
Longitude
27º54’20”
96º48’16”
3.Project TypeRun of River with pondage (more than 3 hours during lean season)
4.Project Capacity6X190 MW & 1X60 MW
5.Catchment Area15,654 Sq. Km
6.Design Flood (PMF)
Glacial Lake Outburst Flood (GLOF)
24,268 cumecs
3,574 cumecs
7.Diversion Tunnels5 Nos @ 14.4 m dia., total length – 5031 m
8.DamConcrete Gravity Dam, 198 m (above deepest foundation level) high, 272 m Long
9.River Bed Level at DamEL 779.5 m
10.Full Reservoir Level (FRL)/ Minimum Draw Down Level (MDDL)
Minimum Tail Water Level (TWL)
EL 904.80
EL 900 m
EL 779.80
11.Live Storage29.76 M cum
12.Sluice Spillway Crest ElevationEL 820 m
13.Head Race Tunnel (HRT)5 Nos.@ 7.5 m dia. & 1 No.@ 8.5 m dia,
Total length – 598 m
14.Design Discharge1128 cumecs
15.Surge Chamber Size228 m (L) X 20.75 m (W) X 63.2 m (H)
16.Pressure Shaft6 Nos, Underground and steel lined, circular, 5 Nos.@ 6.2 m dia., total 899 m long & 1 No.@ 7.0 m dia. (151 m long) bifurcating into 6.2 m (29 m long) & 3.5 m (29 m long)
17.Power House
Rated Net Head
Design Energy
Underground, Vertical Francis Turbine
Main Turbine- 115.4M, Aux. Turbine- 120.24 m
4852.95 MU
18.Tail Race Tunnel3 Nos, circular shape, 11.2 m dia, 3939 m long