|
CONSTRUCTION OF THE MYNTDU LESHKA HYDRO ELECTRIC
PROJECT
(2 x 42 + 1 x 42) MEGA
WATTS
Status of Works of Myntdu Leshka HE Project
INTRODUCTION
The
Myntdu Leshka Hydro Electric Project (2 x 42 + 1 x 42)
MW is a Run Off River (ROR) Scheme, located at the
Jaintia Hills District of the State of
Meghalaya
.
The project envisages construction of the 63 meters’
height dam across the
Myntdu
River
,
just below the tri junction of its two other
tributaries, the Lamu and the Umshariang. The impounded
water is to be conducted to the Power House through a
3313.46 meters’ long and 3.4 meters’ diameter HRT, a
314 meters’ long HPT and 731.25 meters’
long Penstock. The water after generation will be
discharged into the Lyngriang river, which is another
tributary of the Myntdu (downstream). The conductor
system also include an intake shaft gate and a 85
meters’ deep & 8 meters’ diameter Surge Shaft
and a Butterfly valve. Recently, due to severe power
crisis in the State, it was decided to tap all available
potential in the form of Renovation & Modernization
and Upgradation (Stages I & II) and addition of
another unit of 42 MW in the 2 x 42 Mega Watts’
Project, using the same Dam, the same water conductor
system and the same Power House. The capacity of the
Surge Shaft & Intake Gate have been modified to suit
the water flow forces to 3 (three) units. Three penstock
pipes have now been proposed to conduct the water to the
3 (three) Turbines at the Power house.
The
investigation work of the Myntdu Leshka Stage I Hydro
Electric Project (2 x 42) MW was taken up by the Board
during 1975-76 and the final Revised Detailed Project
report (DPR) was submitted to the Central Electricity
Authority (CEA) for clearance, in October 1998. The
public hearing for Environmental Clearance conducted by
the Meghalaya Pollution Control Board (MPCB) was held in
March 1999, of which public has welcomed the Project.
Necessary site clearance from the Ministry of
Environmental and Forests (MOEF) to take up the pre
construction works of the Project was given in August
1999. The Techno Economic Clearance (TEC) was issued by
the CEA vide letter No.2/Meg/2/99-PAC/9499-9522/702 Dt.
20th September
1999
.
The necessary Forest Clearance, subject to certain
conditions, has been accorded by the MOEF vide their
letter No.8-33/2000-FC dated 19.6.2001. The MOEF
accorded Environmental Clearance vide Notification
Ref.No.J-12011/4/99-IA- Dt.20/9/2001. The Meghalaya
State Electricity Board accorded Administrative Approval
for the construction of the 2 x 42 MW Project
vide Board’s Letter No.U/o No.GAP/258/97/vol.I/152
Dt.12/6/02 with a total project cost of Rs 363.08
Crores, including the Interest During Construction
(IDC). While the provisional clearance was received in
June 2002, the final clearance was accorded in May 2004.
At present, the work on the
first 2 (two) units is in an advance stage of
completion, while works on the 3rd Unit also
have started.
The project completion
schedule is as below:-
| Major
Works |
Time
of Completion |
| DAM |
February
2009 |
| TUNNEL |
February
2009 |
| SURGE
SHAFT |
February
2009 |
| PENSTOCK
& PIPE LINER |
March
/ April 2009 |
| POWER
HOUSE (CIVIL) |
April
/ May 2009 |
| POWER
HOUSE (ELECTRICAL) |
April
/ May 2009 |
The commissioning &
commercial operation dates are as follows:
|
Commissioning |
Commercial
Operation
|
| UNIT I |
May 2009 |
June 2009 |
| UNIT II |
June 2009 |
July 2009 |
The
delay in completion and commissioning of the Project are
due to many reasons, the main one being due to
continuous rainfall experienced in the Project site (as
the Project area is located in the southern slope of the
State and it is in the same belt with Cherrapunjee) and
also due to the geological condition in the Project.
The rain
affected the work at the dam which started since May,
2004. Hence
the work had to be stopped and it was restarted from
October 2004 onwards. However the work for the dam was
disrupted again by rain in 2005-2006 and 2007
and in 2007-2008 the work at the power house got
badly affected with a sudden flood in April 2008,
thereby halting the work.
It may be mentioned that both the works involve
working below river bed level and hence rain is bound to
disrupt the work. However the work at HPT has not been
much affected since it is above the river bed level. The
rainfall at the Project site lasted for about six
months.
On completion, the Project would generate about
372.69 Million Units of Electricity annually from the
first two Units. The estimated cost at 1999 price level
is Rs.363.08 Crores and the revised Cost at 2006 price
level is Rs.671.29 Crores, inclusive of the Interest
During Construction (IDC).
SALIENT
FEATURES OF THE PROJECT
A.
DAM
|
Sl.
No.
|
Description of Work
|
TEC
(1999)
|
Current
(2007)
|
|
1.
|
Type
|
Concrete
Gravity
|
Concrete
Gravity
|
|
2
|
Live Storage
|
7.32M
Cubic meters
|
7.32M
Cubic meters
(141.8 X 106M3
|
|
3
|
FRL
|
618.00
meters
|
618.00
meters
|
|
4
|
MDDL
|
606.15
meters
|
606.15
meters
|
|
5
|
Bed Level
|
563.00
meters
|
561.00
meters
|
|
6
|
Length:
(i) Overflow
(ii) Non-Overflow
|
103.75
meters
187.00 meters
|
107.50
meters
212.10 meters
|
|
7
|
Deepest Foundation Level
|
561.00
meters
|
557.00
meters
|
|
8
|
Crest Level
|
597.00
meters
|
587.50
meters
|
|
9
|
Maximum Height
|
59.00
meters
|
63.00
meters
|
|
10
|
Top of Non-overflow section
|
620.00
meters
|
620.00
meters
|
|
11
|
Excavation
|
1.43
Lakh M3
|
6.73
Lakh M3
|
|
12
|
Concreting
|
2.04
Lakh M3
|
3.33
Lakh M3
|
|
13
|
Spillway Capacity
|
12000
Cumecs
|
10,440
Cumecs
|
|
14
|
Gates (Sluices)
|
5
(five) Nos
|
7
(seven) Nos.
|
|
15
|
Gate Size
|
16.75
meters x 17.00 meters
|
8.00
meters x 12.55 meters
|
B.
HRT Intake
:
|
Sl. No.
|
Description
of Work
|
TEC (1999)
|
Current (2007)
|
|
1
|
Type
|
Semi-circular
with trash rack.
|
Semi-circular
with trash rack.
|
|
2
|
Control
|
Fixed
wheel gate operated through shaft.
|
Fixed
wheel gate operated through shaft.
|
|
3
|
Inlet elevation
|
601.41
meters
|
599.55
meters
|
C.
LOW PRESSURE Tunnel:
|
Sl. No.
|
Description
of Work
|
TEC (1999)
|
Current (2007)
|
|
1
|
Type
|
Circular
|
Circular
|
|
2
|
Length
|
3667.00
meters
|
3313.46
meters
|
|
3
|
Diameter
|
3.40
meters
|
3.40
meters (Modified Horse shoe)
|
|
4
|
Design Discharge
|
30.094
cumecs
|
30.094
cumecs
|
|
5
|
Velocity
|
3.21
meters /Second
|
3.21
meters /Second
|
D.
SURGE TANK:
|
Sl. No.
|
Description of Work
|
TEC (1999)
|
Current (2007)
|
|
1
|
Type
|
Restricted
Orifice
|
Restricted
Orifice
|
|
2
|
Height
|
63.50
meters
|
85.00
meters
|
|
3
|
Diameter
|
8.00
meters
|
8.80
meters
|
E.
HIGH PRESSURE TUNNEL:
|
Sl. No.
|
Description of Work
|
TEC (1999)
|
Current (2007)
|
|
1
|
No.
|
1
(one)
|
1
(one)
|
|
2
|
Type
|
Circular,steel
lined
|
Circular,steel
lined
|
|
3
|
Diameter
of Pipe
|
2.60
meters’ diameter
|
2.80
meters’ diameter
|
|
4
|
Length
|
245.00
meters
|
314.00
meters
|
F.
PENSTOCK :
|
Sl. No.
|
Description of Work
|
TEC (1999)
|
Current (2007)
|
|
1
|
Number
|
1
(one)
|
Two
Nos from Butterfly Valve to power house
|
|
2
|
Diameter
|
2.60
meters
|
2.00
meters
|
|
3
|
Length
|
825.00
meters
|
731.25
meters
|
G.
POWER HOUSE:
|
Sl. No.
|
Description of Work
|
TEC (1999)
|
Current (2007)
|
|
1
|
Type
|
Overground
|
Surface
Power House
|
|
2
|
Size
|
34.40
x 21.80
|
54.70
X25.50 meters
|
|
3
|
Gross
head
|
334.00
meters
|
334.00
meters
|
|
4
|
Average
Net Head
|
316.16
meters
|
316.16
meters
|
|
5
|
Type
of Turbine
|
Francis-V
Shaft
|
Francis-V
Shaft
|
|
6
|
Rotational
Speed
|
750
rpm
|
500/600RPM
|
|
7
|
C.L.of
distributor level
|
276.20
meters
|
282.00
|
|
8
|
Generator
Floor Level
|
285.00
meters
|
289.50
meters
|
|
9
|
Maximum
T.W.L.
|
284.30
meters
|
295.29
meters
|
|
10
|
Normal
T.W.L.
|
284.00
meters
|
288.18
|
|
11
|
Minimum
T.W.L.
|
281.40
meters
|
286.78
meters
|
CHRONOLOGY OF EVENTS
The following tables indicate the
important Chronology of events :
|
|
Events
|
|
1975-1979
|
Starting year for the
investigation work of the Project
|
|
August
1997
|
Initial
Detailed Project Report with 3 x 18 Mega Watts’
capacity submitted to Central Electricity
Authority (CEA) for Techno Economic Clearance
(TEC)
|
|
1997
|
The
Central Electricity Authority recommended 2 x 42
Mega
Watts
’
Installed Capacity
|
|
October
1998
|
MeSEB
submitted revised Detailed Project Report
|
|
March 1998
|
Public Hearing Committee
conducted by the Meghalaya Pollution Control Board at
Amlarem & Khliehriat
|
|
September 1999
|
Techno Economic Clearance (TEC)
was obtained (with five years tenure of
completion)
|
|
September 2001
|
Provisional environmental/ site
clearance obtained
|
|
June 2002
|
Provisional Forest Clearance
obtained
|
|
June 2002
|
MeSEB’s Administrative
approval obtained
|
|
25th October 2002
|
Foundation
stone laid by President of India
|
|
May 2004
|
Final
Forest
Clearance was received
The Project works started
thereafter, but due to heavy rainfall in the year,
the works started in full swing only in
October, 2004
|
| Date of starting of works |
Name
of works |
| May 2004 |
Dam
|
| February 2005 |
Tunnel
|
| February 2006 |
Power House
(civil) |
| January 2006 |
Power House (E
& M). Components of E & M items are at different
stages of procurement,
fabrication & erection. |
| May 2007 |
Penstock
|
| December 2007 |
Switchyard |
A BIRD EYE VIEW OF THE DAM UNDER CONSTRUCTION
SPECIAL
FEATURES OF THE PROJECT
1.
Acidity of the Myntdu river:
The pH value of the
Myntdu
River
is around 4.00. The cause of acidity is due to coal mining in the
catchment area. The coal mining is privately owned and is done
unscientifically. It is known that the acid water corrodes steel
and is disastrous toconcrete. While designing various structures,
the environment for concrete and steel has been considered as
extremely aggressive. Anti corrosion steel & stain less Steel
has to be used in structures. In addition, micro silica &
other admixtures have to be added in the concrete to make it more
durable and dense.
2.
Rainfall:
The Project area is located in
the southern slopes of the State and is in the same belt with
Cherrapunjee, which receives the heaviest
rainfall in the world. Due to heavy rainfall, the project schedule
had to be rescheduled many times.
3.
Seismicity:
The project area is located very
close to the Dawki fault. Dawki fault, according to seismologist,
has potential to generate earthquake measuring 9+ in the Richter
scale. In order to ensure stability, all structures have been
appropriately designed to withstand 9+ earthquake impact.
4.
Diversion system:
No Diversion Tunnel has been provided. The water has
been diverted through the river using divider wall upstream and
downstream coffer dam.
PROGRESS
REPORT ON THE CONSTRUCTION OF THE MYNTDU LESHKA HYDRO ELECTRIC
PROJECT, AS ON
31
MARCH 2009
A.
FINANCIAL STATUS:
1.
Sanctioned Cost (with base year):
Rs 363.08 Crores, as per 1999 price index (Including IDC*)
2.
Latest Cost (with base year)
: Rs 671.29
Crores, as per 2005 price index (Including IDC*)
3.
Electricity cost (Rs/ Kilowatt hour)
: Rs 2.68
4.
Debt : Equity Ratio;
70 : 30
5.
Details of Debt to be raised & equity details
: A loan has been arranged from the Rural Electrification
Corporation Ltd and market bonds.
6.
Foreign currency
loan (if any):
Does not arise.
7.
Expenditure up to
end of previous financial year : Rs 423.74 Crores (up to
31st
March 2008
).
8.
Expenditure during
Current year (From 1st April’08 upto
31st March 2009
): Rs
263.63 Crores
(Including IDC)
*Interest
During Construction
A.
PHYSICAL
STATUS:
-
CIVIL
/ HYDRO MECHANICAL WORKS
-
ELECTRO
MECHANICAL WORKS
-
RECEIPT
OF PLANT AND EQUIPMENT
COMMISSIONING
ACTIVITIES:
|
Sl.
No.
|
Items of works
|
Schedule date
|
Actual
date (Present Revised)
|
|
1.
|
Civil
Works
-
Dam/Barrage
-
Water/Conductor
System (HRT)
-
Power
House civil works
-
Tail
Race works
-
Penstock
|
March
2007
March 2007
March 2007
March 2007
March 2007
|
Feb’09-1st
Stage & June’ 09 Final Stage
April 2009
August 2009
August 2009
August 2009
|
|
2
|
Electrical/Mechanical
works
-
Generating
Units
-
Main
step up Transformers
-
Switchyard
-
EOT
Crane
-
Butterfly
Valve
-
LCTAC
Switchgear
-
DCDB
Battery
Banks
-
DG
.Set
-
Power
House Lift
-
Illumination
system
-
Communication
system
-
Ventilation
system
-
Fire
fighting system
|
Nov/08
Nov/08
Nov/08
June/08
Oct/08
Oct/08
Oct/Nov/08
Oct/08
Oct/08
Oct/Nov/08
Nov/Dec/08
Dec/08
Dec/08
|
The
1st Unit is expected to be commissioned in
September, 2009, the
2nd Unit in November 2009 and the 3rd Unit in
June 2010.
|
PROJECT
OVERALL PROGRESS:
|
Date of Approval
(Latest)
|
Expected date of
commissioning
|
Remarks/Reasons of
Slippages
|
|
May/04
(From the Ministry of Environment & Forest)
|
September
2009 for Unit-I
November 2009 for Unit-II
|
Delay
in receipt of MOEF clearance, extra
quantity of work, rainfall, drawings.
|
COST/EXPENDITURE:
|
Latest
approval cost (Including IDC)
|
Cumulative
Expenditure up to
31st
March 2008
|
Cumulative
Expenditure in the year of 2008 – 09 up to
31st March 2009
(Including IDC)
|
|
Rs.671.29*
Crores (As per 2006 price level) including IDC
|
Rs.423.74
Crores
|
Rs.263.66
Crores (Provisional)
|
*
Amount to be revised with the increase in cost due to extra
quantity of works & etc.
A VIEW OF TUNNEL WORK UNDER CONSTRUCTION
|
Leshka Project
