TECHNICAL SESSION S-16 HYDRO-POWER GENERATION-IMPACT ON ENVIROMENT
CONVERSION OF DEVSARI HEP(252 MW) FROM STORAGE TO RUN OF THE RIVER SCHEME ON TECHNICAL,SOCIOECONOMIC AND ENVIROMENTAL ISSUES
BY: R.N.MISRA,DIRECTOR (CIVIL),SJVN LTD. DEEPAK NAKHASI,GM(CIVIL DESIGNS),SJVN LTD K.L.AUMTA,AGM(CIVIL DESIGNS),SJVN LTD HARSH B MEHTA, Sr. ENGINEER ,SJVN LTD.
DATED : 11/04/2013
Scope of the presentation
•
Salient features of the present Run of the river scheme
•
Various Alternative Studies
•
Comparison of various alternatives
•
Conclusion
Salient features of the present run of the river scheme Installed capacity
252 MW
State
Uttarakhand
District River Type of scheme Dam site
Chamoli Pinder Run of the river 1.75 km d/s of confluence of River Pinder and Kail Ganga
Dam Height
35 m(above RBL)
Type of dam
Concrete gravity
Confluence of river Pinder and Kail Ganga
View of dam site
Salient features of the present run of the river scheme FRL MDDL Gross Storage
El 1300 m El 1295 m 9.02 MCM
Live Storage HRT Length Design Discharge Powerhouse Location Tail water level Design Energy
3.21 MCM 17.9 km 120.76 cumec Near Simli gad El 1046.5 m 936.9 MU
Layout Plan of the project
Various Alternatives Studies Alternative 1: 90 m high dam at 1.75 Km D/S of confluence of River Pinder and Kail Ganga having FRL= El 1370 m with TWL= El 1120 m and HRT Length =12.445 km. Alternative 2: 60 m high dam at 1.75 Km D/S of confluence of River Pinder and Kail Ganga having FRL= El 1325 m with TWL= El 1120 m and HRT length=12.445 km. Alternative 3: 35 m high dam at 1.75 Km D/S of confluence of River Pinder and Kail Ganga having FRL = El 1300 m with TWL = El 1120 m and HRT length =12.445 km. Alternative 4: 35 m high dam at 1.75 Km D/S of confluence of River Pinder and Kail Ganga having FRL =El 1300 m with TWL =El 1046.5 m and HRT length=17.9 km.
Various Alternatives Studies Alternative1: 90m high dam and HRT 12.44 km long with TWL El 1120 m Installed Capacity 250 MW Dam Location
1.75 Km d/s of confluence Of River Pinder and Kail Ganga
Dam height
90m
FRL
El 1370m
Submergence
522 Ha
Gross Storage
192 MCM
Live Storage
83.5 MCM
HRT Length
12.445 km
Design Discharge
120.76 Cumec
Powerhouse
Underground
Tail water Level
El 1120 m
Design Energy
890MU
Various Alternatives Studies a) Geological Factor • •
• •
Geological conditions of reservoir area are not suitable for 90 m high dam due to presence of : Multiple shears, active/dormant slides, debris/creep zone and disturbed rock strata on right bank of Pinder River above EL 1300 m and same shall be affected by reservoir fluctuation. Severe slope instability along right bank of Pinder river Presence of two major tectonic planes near confluence of Kail ganga and Pinder river.
Geological map of reservoir area
Various Alternatives Studies b) Socio-economic & Environmental factors •Submergence area: 522 ha. •Approx. more than 20,000 trees under submergence •Affected villages in submergence-13 nos. •Affected population-5000 nos.(approx.) •Submergence of huge cultivable /agricultural land, roads and important religious structures
Populated town under submergence
Various Alternatives Studies
Religious places under submergence
Huge cultivable/agricultural under submergence
Dense forest under submergence
Various Alternatives Studies Alternative 2: 60 m high dam and HRT 12.44 km long with TWL El 1120 m Installed capacity
201 MW
Dam Height
60m
Dam Location
1.75 Km d/s of confluence Of River Pinder and Kail Ganga
FRL
El 1325 m
Submergence
220 ha
Gross Storage
65.32 MCM
Live Storage
28.64 MCM
HRT Length
12.445 Km
Design Discharge
120.76 cumec
Powerhouse
Underground
Tail water Level
El 1120 m
Design Energy
753.36 MU
Various Alternatives Studies a)Geological factors Geological conditions of reservoir area are not suitable for 60 m high dam due to presence of : • Toes of two major slides, one on left bank of Kail Ganga and other on right bank of Pinder get submerged and affected by reservoir fluctuation • Multiple shears, creeping areas along with cultivated lands/old slide debris/talus and active & dormant slides and disturbed rock strata above EL 1300 m. • Tectonic planes near confluence of Kail Ganga and Pinder river.
b)Socioeconomic & Environmental factors •Submergence area: 220 ha. •Approx. 10,000 trees will be submerged /destroyed. •Affected villages to be displaced-3 nos. •Affected population-2000 nos.(approx.) •Submergence of roads and important religious structures The road leading from Dewal to Melkhet and beyond upto the border connecting number of villages shall get submerged at many reaches on route. Prachin nanda devi temple at Purna and Shiv mandir near Devsari bridge.
Various Alternatives Studies Alternative 3: 35 m high dam and HRT 12.44 km long with TWL El 1120 m Installed Capacity
176 MW
Dam height
35m(above RBL)
Dam Location
1.75 Km d/s of confluence River Pinder and Kail Ganga
FRL
El 1300m
Submergence
82 Ha
Gross storage
9.02 MCM
Live storage
3.21 MCM
HRT Length
12.44KM
Design Discharge
120.76Cumec
Powerhouse
Underground
Tail water Level
El 1120m
Design Energy
646MU
Various Alternatives Studies a)Geological factors •
No multiple shears, active/dormant slides and disturbed rock strata problem.
•
All creeping areas and cultivated land remain above FRL El 1300 m and none of them affected by reservoir fluctuation.
b)Socio-economic & Environmental factors •
Submergence area -82 ha.
•
Affected villages due to submergence of only part of 1 village and affected population is only 26 families.
•
Does not involve submergence of any historical/religious places and public structures or any existing road.
•
About less than 2000 trees affected in submergence area.
Various Alternatives Studies Alternative 4: 35 m high dam and HRT 17.9 km long with TWL El 1046.5 m Installed Capacity 252 MW Dam height
35m
Dam Location
1.75 Km d/s of confluence Of River Pinder and Kail Ganga
FRL
El 1300m
Submergence
82 Ha
Gross storage
9.02 MCM
Live storage
3.21 MCM
HRT Length
17.9 km
Design Discharge 120.76 Cumec Powerhouse
Underground
Tail water Level
El 1046.5 m
Design Energy
936 MU
Various Alternatives Studies a)Geological factors •
No multiple shears, active/dormant slides and disturbed rock strata problem in reservoir area.
•
All creeping areas and cultivated land remain above FRL El 1300 m and none of them affected by reservoir fluctuation.
•
Chances of RIS remains less with minimum depth of water column.
b)Socio-economic & Environmental factors •
Submergence area:
•
Affected villages due to submergence of only part of 1 village and affected population is only 26.
•
Does not involve submergence of any historical/religious places and public structures or any important roads.
•
About less than 2000 trees affected in submergence area.
•
This alternatives involves least socio- economic and environmental problem and maximum power benefit.
82 ha.
Details
Alternative 1
Alternative 2
Alternative 3
Alternative 4
Location
1.75 km d/s of
1.75 km d/s of
1.75 km d/s of
1.75 km d/s of
confluence
confluence
confluence
confluence
Dam Height
90m
60m
35m
35 m
FRL
El 1370m
El 1325m
El 1300m
El 1300 m
MDDL
El 1355m
El 1310m
El 1295m
El 1295m
Gross
192MCM
65.32 MCM
9.02 MCM
9.02 MCM
Live Storage
83.5 MCM
28.64 MCM
3.21 MCM
3.21 MCM
HRT Length
12.445km
12.445 km
12.445 km
17.9 km
Design
120.76Cumec
120.76 Cumec
120.76 Cumec
120.76 cumec
D/s of Pranmati
D/s of Pranmati
D/s of Pranmati
Near Simli Gad
Nallah
Nallah
Nallah
I.C.
250 MW
201 MW
176 MW
252MW
TWL
El 1120m
El 1120m
El 1120m
El 1046.5 m
Energy
890 MU
753.60 MU
646 MU
936.9 MU
Storage
Discharge PH Location
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Comparison of various alternatives
Comparison of various alternatives Details Submergence area Population
Alternative 1
Alternative 2
Alternative 3
Alternative 4
522 ha
220 ha
82 ha
82 ha
5000
2000
100
100
20,000
10,000
Less than 2000
Less than 2000
trees
trees
affected due to
Numbers of trees involve
17
submergence
Conclusion
Keeping in view various technical, Socio economic and Environmental considerations and views of GSI Alternative “4� with 35 m high concrete dam having 17.9 km long HRT is considered for adoption and implementation.
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