FIELD VISIT

UPPER KOTMALE HYDROPOWER PLANT

NAME : M.A.V.J. MUTHUGALA

INDEX NO : 090339D

DATE OF PER : 08/9/2011

DATE OF SUB : 23/9/2011

INTRODUCTION

Upper Kotmale hydropower project is a large hydroelectric dam under construction in Talawakele, in Nuwara Eliya in the central province of Sri Lanka. It is planned to be completed in late 2011, the facility will be the third largest hydroelectric dam in the country. Achieving another milestone in the country’s development drive, the longest tunnel which would carry water from the Kotmale reservoir to the underground power station under the Upper Kotmale Hydro Power project which adds 150 MW of power to the national grid.

This project, estimated to cost Rs. 44 billion financed by the Government of Japan and Ceylon Electricity. The construction began in 2006. But this concept is discussed for the first time of the project by the Sri Lankan authorities in 1968 under the Mahaweli scheme. But this project was not implemented in the framework of the accelerated Mahaweli Development Plan.As per the provision in the National Environment Act of 1998, the Environment clearance was granted to the Upper Kotmale Power Project. There were several objections to the project initially and they were settled by the courts of law. The project was implemented under five phases.

The Japanese Government provided a loan of 33,265 million yen, while the CEB making investment 5931 million rupees for this project. Upper Kothmale Power Plant expected to generate 409 GWh of electricity annually from this project and the installed capacity 150MW. The dam will be constructed across the stream Kotmale and the length of the dam is 180 meters and the height is 35.5 meters.

SPECIFICATION OF THE PROJECT

The UKHP is a run of river hydropower project with an installed capacity of 150MW (consisting of two 75MW units) and It will produce 409GWh per year. It has the following components:

A dam located close to the town of Talawakelle with a height of 35.5m and a crest length of 180m. It will have a gross storage of 2.5 MCM with an effective capacity of 0.8 MCM with a surface area of 0.25km2 (60 acres). Full supply level for the reservoir will be 1,194 metres above mean sea level (msl), the minimum operating level will be 1190m msl and the normal tail water level 703m msl.

A headrace tunnel 4.5m/5+.2m in diameter lined and unlined and 12.89km in length, running north from the dam towards the Pundal Oya Falls before turning to the northwest towards the existing Kotmale dam and reservoir. (The maximum gross head between the reservoir and the powerhouse will be 491m).

An upstream surge tank 12m in diameter and 98m high with a restricted opening, located on the crest of the power house.

The penstock formed by an underground incline shaft starting with a diameter of 4.5m and reducing to 1.45m. It will be 793m in length, consisting of one lane of 745m and two lanes of 48m.

An underground powerhouse located at Niyamgamdora, (2km upstream of the confluence of Puna Oya and Kotmale Oya) with dimensions of 66.3m L x 18.8m W x 36.5m H to house two units of 77,000kW turbines, two vertical axis three phase 88,000kVA generators, two 3-phase, transformers and a 220kV Gas Insulator Switchgear (GIS) substation.

An outdoor switchyard, 36.5m wide and 130m long, located at Niyamgamdora, to connect the Power House to a 220kV double circuit transmission line.

220kV double circuit transmission line of 18km length to transmit power generated to existing Kotmale Substation and the associated switch yard extensions.

PROJECT HISTORY

The Upper Kotmale Hydropower Project (UKHP) was conceived with the preparation of a master plan for hydroelectric development in the Mahaweli Basin in 1968. The concepts in the master plan were further studied in 1985-1987 when the Government of Japan funded a feasibility study to examine Hydropower options in the Upper reaches of Kotmale Oya (Stream). Five sites and eight alternative development schemes were examined in the feasibility study and the report concluded that the development of two sites were technically and economically feasible. The two sites were a reservoir type development at Caledonia and a run of river project at Talawakelle. The project at Caledonia involved the displacement of 2700 families and inundation of large area of tea land. The Government of Japan then provided further funding for the Engineering Service Study, which included the review of the feasibility study, selection of the optimal development plan, the development of the detailed design

and preparation of Tender Documents and an Environmental Impact Assessment Report (EIAR). The EIAR was issued in September 1994. The Final Design Report was completed in March 1995. The Environmental Impact Assessment identified key issues associated with the UKHP as, impacts on water fall aesthetics due to stream flow reductions, social impacts due to resettlement of affected people, possible effects on ground water due to tunnelling, impacts due to de-watering of streams on down stream water uses and impacts on bio-diversity.

Further detailed studies on alternatives were completed in 1996 and the Secretary of the Ministry of Forestry and Environment granted approval for the project under the National Environment Act in July 1998 subject to strict adoption of proposed mitigatory measures to minimise possible environmental impacts, which included the development of a watershed management plan, maintenance of daytime flows over the waterfalls, monitoring of groundwater levels, an assessment of biodiversity, management of tunnel waste and a resettlement program. This decision was challenged in the Court of Appeal in October 1998. The Secretary of the Ministry of Forestry and Environment gave final order in March 2000, subsequent to the settlement of the appeal.

The Government of Sri Lanka secured financial support in March 2002 from the Government of Japan to implement the project, signing of Loan Agreement SL-P74 in March 28, 2002.

The decision of the Secretary in March 2000 was further strengthened with the Gazetting of the National Environmental (Upper Kotmale Hydro-power Project – Monitoring) Regulations No. 1, 2003.

SCOPE OF WORKS

The Upper Kotmale Hydropower Project will be implemented through five separate contracts comprising of Lots

1 to 5.

Lot 01 - Preparatory Works

Lot 1, Preparatory Woks is aimed at preparing the site for the other Lots to commence, including construction of

all facilities to the Project Affected Persons. Main part of the lot

Access Road to the Respective Construction Sites

Permanent Facilities for the Employer and the Engineer

Permanent Facilities for the Re-settlers

33 kV Construction Supply line

In this session Building access roads with drains,

culverts and bridges to the respective construction

site. In here the improvement of existing road was

also done.

This consists of constructing and providing

permanent facilities for the persons affected by the

project. The re-settlers are mainly estate workers but

include a good number of varied occupants, shop

owners, workshops, garages etc. Their new houses

was planned to construct in an area which is close to

their residential places .And also For a village a new

school, a new hospital, a new cinema hall were to be constructed. The resettles have now being offered modern

new homes with most of the common facilities (electricity, Water supply) and some of them have great sceneries

and views to their homes.

Lot 02 - Main Civil Works

Main Civil Works is the largest lots out of the five lots of having more

than half of the project cost will be used to construct civil works. This

takes about 50% of the project cost. Main part of the lot

Main Intake Dam

Waterways

Powerhouse Complex and Switchyard

Lot 03 - Hydro Mechanical Equipment

Hydro-mechanical works such as construction of spillways, penstocks, intake gates, etc. Main part of the

lot

Main Dam and Intake at Talawekele

Diversion Waterway and Power Station

Discharge Facility for St. Clair’s Water Fall

Lot 04 - Electro Mechanical Equipment

Electro-mechanical works such as generation installations, construction of the switchyard, fire fighting

system, communication system, etc. Main part of the lot

Turbine Generator

Overhead Traveling Crane Power Transformer

Switchyard Equipment Power Plant Equipment

220 kV XLPE Power Cable Telecommunication Equipment

Miscellaneous Equipment Metal Enclosed Switchgear at Intake Dam

Expansion of Kotmale 220kV Switchyard Expansion of 33kV Nuwaraeliya Grid

Substation

Lot 05 - Transmission Line

In this lot required to construct a 220 kV transmission line of 15.5 km from the proposed Upper Kotmale

Hydropower Station (Niyamgamdora) to switch yard of the Kotmale power station (Atabage). The transmission

line consists of 45 Structured Towers of steel angles and 6 Steel Reinforced Aluminum Conductors (ACSR) fixed

to each tower using strings of Insulators with associated hardware.

Additionally, an Aluminum Clad (AC) Earth Wire and an Optcal Fiber

Ground Wire (OPGW) with associated hardware are drawn through each

tower from one end to the other.

The transmission line traverses through the Grama Niladhari Divisions,

namely Kalapitiya East, Kalapitiya West, Weerasekarapura,

Koththunugoda, Rojasangama, Wataddara, Thispane Kanda, Harangala,

Kadadora, Mawathura, Nayapana, Kekulanda, Galatha which come under

purview of Divisional Secretariats of Kotmale and Udapalatha

(Gampola).

DAM AND RESERVOIR

The gravity dam measures 35.5 m (116.5 ft) tall, and 180 m (591 ft)

wide, impounding the Kotmale River and creating the Upper Kotmale

Reservoir. Once filled, the reservoir will have a surface area of 250,000

m2 (2,700,000 sq ft) with an average storage capacity of 800,000 m3

(28,000,000 cu ft). The minimum and maximum operating water levels

are 1,190 m (3,904 ft) and 1,194 m (3,917 ft) AMSL respectively, while

the tailwater level is 703 m (2,306 ft) AMSL.Water from the reservoir

will be used for both irrigation development and hydroelectric power generation.

TUNNEL

The 4.5–5.2 m (14.8–17.1 ft) diameter, 12.89 km (8.0 mi) long Upper Kotmale Tunnel, the longest excavated

tunnel in Sri Lanka, will be used to deliver the water to the powerhouse. The tunnel begins at the dam site, and

stretches north at a distance of approximately 7.4 km (4.6 mi) towards Pundaluoya, before stretching a further

5.5 km (3.4 mi) north-west towards Kumbaloluwa and ending up at its powerhouse at the Kotmale River near

Niyamgamdora, at approximately 07°02′33″N 80°39′23″E, 2 km (1.2 mi) downstream of the confluence of Pundal

River and the Kotmale River. Construction on the tunnel was completed and ceremonially opened by President

Mahinda Rajapaksa on the 4th of November, 2010

POWEHOUSE

The powerhouse measures 66.3 m (217.5 ft) long, 18.8 m (61.7 ft) wide,

and 36.5 m (119.8 ft) tall, and is located underground at Niyamgamdora.

It has installed electrical capacity of 150 MW from two 75 MW turbines,

capable of producing up to 409 GWh of power annually. Water arrives at

the powerhouse from the dam via the 12.89 km (8.0 mi) long Upper

Kotmale Tunnel, which then feeds the 793 m (2,602 ft) penstock. The

initial 745 m (2,444 ft) of the penstock is single-lane, while the latter 48 m

(157 ft) splits into two lanes, feeding the two 75 MW generators

respectively.

The powerhouse consists of the two three-phase 77 MW, 80,000 kVA

vertical-axis turbines and generators, two three-phase transformers, and a

220kV Gas Insulator Switchgear (GIS) substation. An outdoor switchyard

measuring 36.5 m (119.8 ft) by 130 m (426.5 ft) would then connect the powerhouse to the national grid via an

18 km (11 mi) long 220-kV double-circuit transmission line which connects the switchyard to the national grid at

the existing Kotmale Substation at 07°07′18″N 80°34′51″E. Two megawatts from each of the generators will be

utilized to run the Upper Kotmale facility itself, thus the net production will be 150 MW instead of 154 MW.

SOCIAL AND ENVIRONMENTAL IMPACT

The construction of the dam, tunnel, and powerhouse, required the

relocation of families from 495 houses. New homes were built away

from the site with access to vital facilities such as water and power.

The relocated families are provided with concessionary loans to start

new self-employment ventures, while additional facilities such as the

Talawakele Central College, places of worship, a cinema hall, a

library, and a community centre, are being established.

Similar most other dam's impacts on rivers around the world, the

Upper Kotmale Dam will periodically stop the St. Clair's Falls, located 2.2 km (1.4 mi) downstream of the dam,

and a further 2.9 km (1.8 mi) of the Kotmale River downstream of St. Clairs Falls, before the river is restored by

water from the Devon River, the river forming the picturesque Devon Falls. As ordered by the Government

Extraordinary, the St. Clair's waterfall will maintain a continuous flow of 47,250 m3 (1,668,618 cu ft) of water for

10 hours and 30 minutes daily, between sunrise and sunset.

Facilitators:

Mr.Shavindranath Fernando Mr.R.S.W.Wagarachchi

References:

http://www.ukhp.lkhttp://www.wikipedia.org/wiki/Upper_Kotmale_Damhttp://www.sundaytimes.lk/101107/News/nws_07.htmm