【Ex-Post Monitoring of Completed ODA Loan Project】
Sri Lanka“Samanalawewa Hydroelectric Power Plant (I) (II) (III) andSamanalawewa Hydroelectric Project (Reservoir Remedial Works)”
External Evaluator: Jun Kuwabara,(International Development Center of Japan Incorporated)
1.

Project Description

Project Location

Samanalawewa Dam

1.1 Project Objectives
The objective of this project was to address the shortage of electricity supply in Sri Lanka by
constructing a reservoir-type hydroelectric power plant with a maximum output of 120 MW in the
upstream of Walawe River, approximately 160 km southeast of Colombo, thereby contributing to theeconomic development and improvement of the welfare of the country.
1.2 Outline of the Loan Agreement
Loan Approved Amount/

1st Phase: 14,500 million yen/14,500million yen

Disbursed Amount2nd phase: 13,920 million yen/13,920 million yen
3rd phase: 3,264 million yen/3,264 million yen(Remedial works): 5,282 million yen/3,134 million yen

Loan Agreement Signing Date/

1st Phase: July 1986/September 1992

Final Disbursement Date

2nd phase: July 1987/April 1994
3rd phase: January 1991/March 1995
(Remedial works) : July 1995/March 2005

1

Ex-post Evaluation

2006

Executing Agency

Ceylon Electricity Board (CEB)

Main Contractor

Joint venture of Kumagai Corporation (Japan), Hazama Corporation(Over 1 billion yen)

(Japan), and Kajima Corporation (Japan)

Main Consultant

Nippon Koei Co., Ltd. (Japan)(Over 100 million yen)

1.3 Background of Ex-post Monitoring
Along with the steady economic growth of the country, the electricity sales in Sri Lanka grew
rapidly by 8.2% per year on average from 1980 to 1985, and the demand for electricity was predicted tofurther increase. As a measure to cope with such increase in demand, the Government of Sri Lanka(GOSL) planned to operate large-scale coal-fired power plants, which estimated a huge delay in actual
construction. The gap between electricity demand and supply was then anticipated to become severe in
the first half of the 1990s. This project was planned with the aim of alleviating the disproportionate
supply-demand situation for electricity.
This project was co-financed by Japanese ODA loan and loans provided by the U.K. The Japanese
ODA loan was extended to the construction of diversion tunnels, dam, hydraulic turbine and penstock,and construction management cost, while U.K Portion was extended to the construction of intake andwaterway, power generating mechanical plant and design cost. During the construction of the dam in
1988, a highly permeable section was found in the ground of the right bank, and CEB modified the
project plan to add cut-off work (curtain grouting), etc., to which the remaining amount of the third phaseof the Japanese ODA loan was disbursed. After the completion of the construction, when the water-filling
test was conducted in the reservoir in 1992, a large amount of water leakage occurred from the right bankinto downstream areas. The GOSL set up an “International Panel” to examine potential countermeasures
to address this problem. As a result, it was decided to implement the wet blanketing method2 (remedialwork) as a countermeasure. For the remedial work, Japanese ODA loan was disbursed starting from 1995.
The overall rating in the ex-post evaluation conducted in 2006 for this project was “D”(dissatisfactory) mainly for the following reasons:・The actual project period exceeded the plan due to the additional work against water leakage, which
resulted in the rating “B” for the project efficiency.

・The actual annual power generation was lower than planned, mainly due to the decrease of water
discharge for electricity generation that mainly comes from the decrease in rainfall and the increasein discharge of irrigation water, which resulted in the rating “B” for the project effectiveness.

・

Water leakage from the right bank into downstream areas rapidly increased although the main cause
was not detected when the field survey for the ex-post evaluation was conducted. Challenges wereadmitted for securing safety on a long-term basis, and the project sustainability was rated as “C”.

2

Observing that the water leakage decreased as the reservoir water level lowered, the ex-post
evaluator concluded to draw a recommendation to CEB. That is "Continue observing the amount ofleakage, water quality, reservoir water level and the groundwater level at the right bank while
maintaining the low water level and at the same time consider taking measures as necessary based on the
study undertaken by experts and the results of additional surveys, measurements and analyses to be
conducted when necessary."
Therefore, this project was selected for ex-post monitoring and reviewed under each criterion,
particularly to assess the project sustainability, and to reconfirm the project effectiveness and impact, withthe findings from the field survey and other research activities with a final conclusion being drawn.

2. Outline of the Monitoring Study
2.1 Duration of Monitoring Study
Duration of the Study: January-September 2012
Duration of the Field Study: July 4-16, 2012
2.2 Constraints during the Monitoring Study
Not applicable.
3. Monitoring Results
3.1 Effectiveness
3.1.1

Quantitative Effects

3.1.1.1

Results from Operation and Effect Indicators(1) Net Electricity Energy Production
Table 1 shows the operation and effect indicators of the project: net electricity energy production andmaximum output from 2006 to 2011. The average of annual electricity energy production through to 2011reached 298 GWh, which is higher than the average at the time of ex-post evaluation in 2006 (271 GWh).
It was however lower than the design energy of 462 GWh, revised energy of 403 GWh, and mid-term
annual generation forecast by CEB of 344 GWh.

3

Table 1: Net Electricity Energy Production and Maximum Output of Samanalawewa Dam (2006-2011)
2006
2007
2008
2009
2010
2011
1996-2011
Average
Net Electricity
294.5
229.3
312.8
285.4
375.4 292.2
298
energy production(GWh)
Maximum Output
Over 120 Over 120
128
128
130
128
Over 120(MW)
GWhPlanned Annual Power Genera on(1986:462GWh)

450

Revised Annual Power Genera on（1995:403GWh)
400

Annual Power Genera on by CEB Genera on Plan (2006:344GWh)
350
300
250
200
150
100

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

1996

1995

1994

1993

0

1992

50

Source: Developed from CEB data.

Figure 1: Comparison of Designed Energy and Actual Power Generation at Samanalawewa
Hydroelectric Power Plant
The ex-post evaluation made analyses on the major reasons that caused the power generation to belower than planned. Those were annual rainfall into the catchment area and water inflow into the dam
reservoir decreased and the discharge volume of irrigation water increased.
In this ex-post monitoring, the data of monthly water inflow and rainfall from 2006 to 2011 were
newly collected and added to the ones obtained at the ex-post evaluation, which are shown as Figure 2
and Figure 3.
The planned average inflow volume to the reservoir was estimated at 17.9 m3/s per year, based on
the actual volume of 18.5 m3/s measured from 1959 to 19791. Average volume of water inflow from1996 to 2011 is lower every month than that from 1959 to 1979 as shown in Figure 2, and the annual
average from 1996 to 2011 remained at 14.2 m3/s, which is 79 percent of the designed figure. It wasestimated that the smaller volume of water inflow into the reservoir has reduced 90 GWh annually fromthe total power generation.
The lower water inflow was caused by the decrease in rainfall as shown in Figure 3. Annual rainfall
from 1996 to 2011 is 1,940 mm on average, which is approximately 83 percent of that of 1959 to 1979:

1 For both average volume of water inflow and annual rainfall, the measured amount from 1959 to 1979and planned amount at the time of project planning were referred in the Ex-Post Evaluation.

4

2,320 mm.

m3/s

30.0

25.0

20.0

15.0

10.0
1959‐1979

5.0

1996‐2011
0.0
Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Figure 2 Comparison of Water Inflow before and after the Project (Monthly Average)
mm
400.0
350.0
300.0
250.0
200.0
150.0
100.0
1959‐1979
50.0

1996‐2011(NotIncluded2000)

0.0
Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Figure 3 Comparison of Rainfall before and after the Project2 (Monthly Average)
From the Samanalawewa Dam, irrigation water is discharged to the Kaltota Agricultural District
downstream without going through the power station. The water leakage from the right bank and water
discharge through the dam are spent for irrigation, and the actual average volume of discharged waterfrom 1996 to 2011 is 92 million m3 annually (2.9 m3/s), which far exceeds the original plan: 50 million
m3. It was roughly estimated that this difference has caused a reduction in power generation by 40 GWh
per year.
(2) Maximum Output

Maximum output had been recorded around 120 MW since 2006 to 2011 (see Table 1), although
their duration of peak generation was short. And it can be said that the output was utilized to copewith the peak electricity demand.
2 Rainfall data of February 2000 was missing and it was not taken into account in the Figure.

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3.1.1.2

Results of Calculations of Internal Rates of Return (IRR)

The data from 1992 to 2004 obtained at the ex-post evaluation were found to be unreliable3, andcollecting the necessary information and data during the said period was not possible in this study
although data from 2005 to 2011 was available. Due to incomplete collection of such data, the ex-postmonitoring did not undertake a recalculation of FIRR and EIRR.
The EIRR calculations up to the ex-post evaluation were based upon the cost required for a thermal
power plant at same scale which drew superiority in cost for hydroelectric power station.
Operation cost per electricity generation unit by hydroelectric power generation facilities stays lower
than that of diesel thermal power generation facilities in Sri Lanka, and it is inferred that hydropower
generation still has advantages in prices against thermal power generation.
3.1.2

Qualitative Effects

Not applicable.
Although the electricity energy production has not reached the planned target due to a decrease iswaterfall and other factors, the average power generation from 2006 to 2011 exceeded the average up to
the ex-post evaluation (2006). In terms of enhanced electricity energy production and moderate operation
cost, the project is still found effective at the time of ex-post monitoring.
3.2 Impact
3.2.1

Intended Impact

3.2.1.1

Stable Electricity Supply

Table 2 shows major electrical indicators of Sri Lanka from 1986 to 2011. Increase in demand forelectricity in the country during the said period was prominent, and the annual electricity energy
production and peak demand of 2011 rose to approximately 4.3 times and 4 times greater than that of1986 respectively. The annual average electricity energy production of Samanalawewa was 298 GWh up
to 2011, which shared 2.8 percent of total energy production of the country (10,714 GWh). Peakelectricity capacity of Samanalawewa is 120 MW, which had a share of 5.5 percent of the peak demandnationwide in 2011. Although the share of the Samanalawewa Power Station was on decrease as the total
annual electricity production and peak demand in Sri Lanka keeps increasing, it is confirmed that the
Samanalawewa Power Plant has contributed to stable electricity supply of the country.
Table 2 Electrical Indicators Nationwide
1986 (Project
2004
commencement)

2011 (Ex-Post
Monitoring)

3 In this study actual data of O&M cost from 2005 up to present were collected, which are 10

times more than that up to 2004. The ex-post monitoring team revealed that the operation costin 1992 was not taken into account, for instance. O&M cost was found to be an estimate, notactual data, with parameters such as electricity production.

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Installed Capacity (MW)1,065

Annual Electricity Energy
Production (GWh)2,652

Peak Electricity Demand (MW)540

Household Electrification Rate
(%)

17

2,280
(2.1 times)
8,159(3.1 times)
1,563(2.9 times)
71(4.2 times)

3,141(2.9 times)
10,741(4.3 times)
2,163(4.0 times)
91(5.4 times)

Source: CEB Statistics
Note: Figures in parentheses are comparison with those of 1986.

3.2.1.2

Increase in Electricity Energy Consumption and Contribution to Economic Growth

GDP at constant prices, real economic growth rate, GDP per capita at constant prices, and per capita
growth are shown in Table 3. Since the Samanalawewa Power Station started operation in 1992, GDP
has shown steady growth although it dropped when a severe recession occurred in 2001 caused bycomplexity of long-time civil war, terrorism, poor crops due to severe drought and power failures and by
global financial crisis in 2008 that was caused by economic downturn precipitated by the Lehman
Brothers bankruptcy. GDP per capita also increased greatly from 557 USD in 1992 to 2,835 USD
reflecting the same tendency as GDP. Figure 4 gives an implication that the electricity energy production
increased steadily, as the country’s economy grew, to which the Project made a contribution.
Table 3 GDP and Real Economic Growth Rate
1992
1995
2000
2005
GDP (Mil. USD)
9,703
13,03016,331
24,406
GDP Growth Rate (%)
5.6
5.0
4.0
GDP Per Capita (USD)
556.8
718.4
854.9
1242.4
Average Growth Rate (%)
4.3
4.0
3.4

Mil USD

2010
49,568

2011
59,1726.4

8.3

2,400.0

2,835.4

5.3

7.1

GWh

60,00012,00050,00010,00040,0008,000

30,0006,000

20,0004,000

10,000

2,000

0

0
1992

1995
GDP(Mil. USD)

2000

2005

2010

2011

Gross Power Genera on(GWh)

Source: World Bank, World Indicators, 2012, and CEB data.

Figure 4 GDP Growth and Gross Power Generation
Table 4 shows the industrial sector and service sector grew rapidly compared to the agricultural
sector up to 2005. Although the share of industrial sector has been at a standstill since 2005, outputs

7from these two sectors keeps growing. Further development of the two sectors requires stable electricity
supply, and the Project meets such immediate needs for the country’s economic growth and thus has had
a positive impact on the country’s economic development.
Table 4 Structure of GDP
Sector

1992

1995

2000

(Unit: %)

2005

2010

2011

Agriculture

23.5

20.6

17.8

11.8

12.8

13.7

Industry

23.3

23.8

24.4

30.2

29.4

27.8

Manufacturing(14.0)(14.1)(15.1)(19.5)(18.0)(17.2)

Service

44.1

45.2

47.3

58.0

57.8

58.5

100%
90%
80%
70%
60%

Service50%

Industry

40%

Agriculture

30%
20%
10%
0%
1992

1995

2000

2005

2010

2011

Source: World Bank, World Indicators, 2012.

Figure 5 Structure of GDP
Therefore, it was confirmed in this ex-post monitoring that the Project still plays a crucial role incontributing to stable electricity supply in Sri Lanka, enhancement of economic growth and improvementof social welfare.
3.2.1.3

Impact on the Natural Environment

No serious impact on the flora around the dam reservoir was reported from the interview with CEBstaff and local residents as of the ex-post evaluation in 2006.
CEB obtained ISO14001 in December 2006, and the Samanalawewa Power Station has listed 672
items that might affect natural environment which accordingly are checked every two months. CEB
selected and carefully monitored 102 out of 672 that were identified as the most critical items having
impact on natural environment. CEB conducted monitoring on water quality at dam reservoir (one site),
upstream (four sites), and downstream (two sites). Monitoring results up to 2011 indicated that all figures
have stayed within the national environmental standards. CEB continues monitoring the flora every
month as of December 2006 when CEB obtained ISO 14001, which has had no problems up to now.

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3.2.1.4

Land Acquisition and Resettlement

It was Rathnapura District and the relevant Divisional Secretariat (DS) under the District that took
initiatives in land acquisition and resettlement of the local residents, through which CEB made payment
for compensation. Three DSs were involved as the project area was across three administrative
boundaries. CEB has received periodic reporting from them about the progress of resettlement.
At least two households have not received relocation and compensation payment in the project area.
Relocation and compensation payment was on progress for 49 households at Handagiriya site when the
ex-post evaluation was conducted. As of July 2012, it was found 48 households already completed theprocess. In Imbulpe district, one household did not agree to resettle and will take further time forreconciliation although the objection was unknown. The remaining households are located beyond the
maximum water level of the reservoir (Mean Sea Level: MSL 460m) and there was no impact on projectcontinuation. The number of local residents who used boats to cross the reservoir decreased as they
relocated to other places, and CEB implemented a boat service.
Brief interviews were conducted with resettled peoples in this ex-post monitoring. Many of them
reported dissatisfaction for not being given the certificates of their land tenures. The details of theincidents were kept unknown as it had been nearly two decades since the resettlement started in the latter
half of 1980s, and the DSs were not reached in this study. It was confirmed in this study that theresettlement procedure has not been completed yet.

Source: Ex-Post Evaluation Report.

Figure 6 Samanalawewa Dam Reservoir and Surrounding Area
3.2.1.5 Other Impacts(1) Impact on Irrigation Works
CEB provides water from the Samanalawewa Dam downstream to the Kaltota Agricultural Area for
irrigation works based on the request from the Department of Irrigation and in agreement with the Water

9

Management Board. The water coming from the leakage on the right bank of the Dam is regarded as partof the water outflow from the Dam. Some interviewees replied that their paddy yields have increased
since the Samanalawewa Dam Reservoir started operation, along with the innovation of agricultural
technology.

Picture 1 Kaltota Agricultural Area (overview, close-up view and canal)
The water outflow from the power station which bypasses the dam is used as irrigation water
downstream in the Katupath Oya Agricultural Area. The ex-post evaluation mentioned that the increase in
the water flow downstream contributed to the irrigation works in the basin of Walawe River, which isfurther downstream from the said agricultural areas. However, the Uda Walawe Power Station (Reservoir)
is located 2 km downstream of the Katupath Oya Agricultural Area, where no irrigated area is identified
in the satellite image. Therefore the contribution to the irrigation in other places than the said two
agricultural areas was found to be limited.
(2) Impact on Regional Development
According to the ex-post evaluation, a 23 km road was constructed as an access road for construction
work and the road was used as a general road by the local residents in their daily lives. The road was
operated and maintained by the Samanalawewa Power Station, and handed over to the Road
Development Authority (RDA) in 2006. The chief engineer of the power station was of the opinion thatthe road condition had been improved and better managed since then. The traffic volume in 2012 was
50 vehicles per day on average.
Using the land where the temporary work station of the Project was located, a new university(Sabaragamuwa University) was established. The university increased the number of faculty andenrollment of students, and there are 170 staff members and 2,900 students enrolled as of the end of 2010.
A youth training center which was built near the sluice gate of the headrace tunnel was also part of thework station. There are training programs implemented at the center that are still up and running. One
temporary building for the construction period near by the access road to surge chamber was handed overto Department of Agriculture. This building was also used for training and research activities for them.

10Picture 2 Access Road

Sabaragamuwa University Youth Training Center

Therefore, it is confirmed that the Project has brought certain positive results to the stable power
supply, social welfare, economic growth and regional development. There was significant progress madein paying compensation to the resettled local residents, however this has yet to be completed.
3.3 Sustainability
3.3.1

Structural Aspects of Operation and Maintenance

CEB is a fully government-owned public corporation under the supervision of the Ministry of Powerand Energy and has 16,192 employees as of the end of 2011. Independent power producers (IPPs) havebeen established in some areas recently as power generation is no more a government monopoly as aresult of the energy sector reform. The details and schedule of further implementation of sector reform
have not been decided yet, and CEB will continue being engaged in power generation, transmission, anddistribution.
The Samanalawewa Power Station belongs to the Generation Headquarters of CEB. There were 106
staff members working at the Power Station at the time of ex-post evaluation, and this increased to 122 asof July 2012. There has been however no change in the organizational structure, and the additional 16
members were allocated to vacant positions.
3.3.2

Technical Aspects of Operation and MaintenanceTechnical staff members at the Samanalawewa Power Station have adequate educational
background and years of experience. Training opportunities are provided to CEB staff annually in asystematic manner by CEB and the power station. External and internal training courses conducted at
CEB are varied and offer over 20 programs, and internal program in particular, are well planned based on
ISO9001 and CEB’s mid-term vision. A wide range of the contents of the training includes emergency
operations, public health and daily vehicle maintenance, etc.
3.3.3

Financial Aspects of Operation and MaintenanceAccording to the Financial Annual Report 2011, CEB had deficits in its current account of as muchas 18 billion rupees in 2011. Overall, the financial structure of CEB is not in good shape. CEB’s financial
deterioration has not been resolved yet mainly because share of low-cost hydroelectric power generationis on a decrease, oil price hikes and the increase in payment to IPPs. The Public Utilities Commission of
Sri Lanka (PUCSL) is now mandated to regulate the electricity sales price in Sri Lanka, and it was

11expected that CEB’s financial structure should improve accordingly. However CEB falls into deficit
whenever electricity energy production by hydroelectric power generation facilities is reduced due todroughts.
Although CEB often suffers from financial deficits, CEB makes a decision to allocate sufficientbudget for the operation and maintenance of the power stations with a high level of priority because it
immediately affects the electricity sales. Therefore, no problems have occurred so far in the operation andmaintenance of the Samanalawewa Power Station due to shortages of finances.
3.3.4

Current Status of Operation and Maintenance3.3.4.1

Region-wide Integral Operation

The Samanalawewa Power Station adjusts its power production according to the maintenance statusof other major hydroelectric power generation facilities and water levels of their dams located in the
Mahaweli system and Laxapana system, by the orders of the National System Control Center located in
Colombo. However, no indicators were confirmed in this study that reflects such regional operation’s
influence. The natural environmental condition and operational status differs in each power station. For
example, they allocate more water for irrigation works in the Mahaweli system, which limits the amountof water discharged for power generation. The volume of water stored differs by dams. With thesevariations taken into consideration, electricity energy production which can be better managed by water
system and further contribute to the effective usage of water resources for the entire nation
3.3.4.2

Organizational Management

Following ISO9001, Samanalawewa Power Station was awarded with ISO14001 in December 2006,
and has updated certifications periodically. It has enabled Samanalawewa Power Station to make prompt
decisions by managing all the documents, sharing all information among staff and coping with criticalissues by core members.
3.3.4.3

Procurement of Spare Parts

It was mentioned in the ex-post evaluation that it took longer time for CEB to procure spare parts forthe equipment and facilities of the Samanalawewa Power Station. A spare parts manufacturer recently
opened its office in India, which helped CEB procure needed parts quicker and problems were mitigated.
3.3.4.4

Deterioration of Equipment

It has been approximately 20 years since the Samanalawewa Power Plant commenced operations in
1992. Equipment and facilities at the power station have deteriorated due to usage over time, out of which
the following four are in critical condition:(1) Breakdown of monitoring control systems of generators
Three out of four monitoring control systems of power generators have broken down, so power plantstaff monitor and control the generators using the sole remaining one. If the remaining one should also
break down, the generators could be operated manually without taking into account various indicators

12

such as water temperature. The spare parts of the broken down equipment are no longer available, andrepair work is not possible. It has turned out that it would cost 500 million rupees to replace all the
relevant equipment of the monitoring control system. As of July 2012, they were examining alternatives
with lower cost in the formed technical committee.
(2) Deterioration of Quality of Rock Material
The rock material of the dam, to a wider range, has oxidized and deteriorated as it experienced
expansion and contraction due to exposure to sunlight, heat and cold. Most deteriorated rock became
sandy, and it could not bear strength to sustain the structure. It is time to replace this, and selection of
new rock material will require judicious technical examination, such as rock composition, in order not torepeat similar problems in the near future. As of July 2012, CEB was examining countermeasures with
the University of Peradeniya.
(3) Breakdown of Programmable Logic Controller
The programmable logic controller, PLC, had been out of order for the gate system of the spillway.
Taking into account the precipitation probability in Samanalawewa, only once in four to five years does
CEB operate the gate system. They currently operate the dam at 5 m lower than the maximum level of thereservoir, which requires less need for operating the gate system. It was estimated to cost 20 to 30 million
rupees to replace the PLC, which is affordable for CEB.

Picture 3 Monitoring Control System

Deteriorated bedrock

PLC(4) Breakdown of Guard Valve
The guard valve is connected to the one which allows water
discharge for irrigation. The power station keeps discharging water
for irrigation throughout the year. They open and close the valve
when they conduct periodic maintenance once or twice a year. As
the valve is broken, CEB staff opens and closes it manually. As of
July 2012, CEB was negotiating with the equipment suppliers on the

Picture 4 Guard Valvereplacement of equipment and prices.
3.3.4.5

Water Leakage(1) Background

13
Picture 5 Water Leakage PointCEB conducted an initial survey in December 2006 with in which they tried to detect the cause of
the sudden increase of water leakage. CEB agreed to take an immediate action in October 2007 in
response to the recommendations drawn in the ex-post evaluation, with economic viability of the dam
operation secured.
The amount of water leakage surged to 4.6m3/s in December 2006, which marked the high point.
The amount of water leakage lowered in June 2007, and it was around 2.5 m3/s after 2008, although it isslightly above the average of 1.8m3/s for the ten years from 1996 to 2006.
(2) Safety Measures
CEB reconfirmed that the long-term structural safety of the dam would not be secured while it had
water leakage. In order to lower the water pressure at the leakage point, they decided to lower the
maximum level of water by 5m up to 455m. They revised the operation manual to cope with the waterleakage, and built an early warning system for the downstream areas. CEB also supported the local
administrative bodies to develop and implement a disaster drill in order to enhance their preparedness
against disasters.
(3) Surveys to identify the cause of water leakage
There were two surveys in which countermeasures were examined and recommended to deal withthe water leakage at the dam reservoir. Those were a doctoral dissertation by Dr. L.B.Kamal Laksiri(Project Director Bloadlands Hydropower project of CEB) and its follow-up survey, and another survey
done by W.B. Atkins Co., Ltd. Table 5 shows the outlines of two surveys.
Table 5: Outlines of Surveys
PeriodMethodScope

Dissertation of Dr. L.B. Kamal Laksiri

Survey of W.B. Atkins Co., Ltd2007 and follow-up survey (in progress)
Comparison of water level between wells
and reservoir

2008-2009
Analysis of water flow by using
magnetism and electricity
Places without grout curtains anddislocation areas on the right bank

All the monitoring wells on the right bank

Identification ofwater leakage
point
Further study
Recommended
countermeasures

415 m MSL on the right bank
Location finding by Isotope
Extension of dry or wet blanket

439m MSL on the right bank (places
without grout curtains)
Large-scale survey
Extension of grout curtains (project cost:high)(4) Future Direction
CEB has not made any decision yet if it will conduct further surveys, develop and implement
countermeasures. The Generating Department of CEB is torn into several ideas since water leakage is acomplex mechanism and countermeasures are not yet proven. Some said that those countermeasures withlower cost should be tried first.
The Ministry of Power and Energy had paid keen attention to this issue, and the Minister ordered
CEB to conduct a follow-up study in 2011 to detect the leakage point by using isotope based on the14

recommendations of Dr. Laksiri. A water ingress zone in the right bank was estimated to be located atabout 415m MSL within about 100m distances along the right bank from the dam body. Furthermore,water ingresses into the right bank in above location, moved in different paths with different distancebecome coming to the outlet.

They scheduled to conduct another survey to further identify thelocation.
At the time of ex-post evaluation, no problem was found for technical, organizational and financial
sustainability of CEB. It was confirmed in this ex-post monitoring that they have continued and enhancedsuch sustainability to some extent: they have provided technical training opportunities systematically, andenhanced management by allocating required personnel and acquiring ISO9001 and ISO14001.
Recurrent budget for the operation of the power station has been allocated with high priority. It was
confirmed that sustainability was maintained or enhanced in terms of these three aspects.
Equipment and facilities have deteriorated as it has been 20 years since they started to operate thepower station. CEB had detected which equipment and facilities were broken down and examinedcountermeasures to implement. Although they confront challenges in budget, they should take appropriate
actions in a timely manner.
The water leakage that has existed since the initial operation of the power plant station and saw atemporary increase in 2006 has continued up to present. It was confirmed in this ex-post monitoring that
CEB has been making efforts to operate the power station with safety measures well taken, and tocontinue conducting studies to reach further solutions.
4.

Conclusion, Lessons Learned and Recommendations

4.1 Conclusion
The Samanalawewa Hydroelectric Power Plant presently supplies electricity in a stable manner,
more than the average amount from 1992 to 2005 although it has not reached the planned level yet, andoperates to cope with peak demand. Water inflow to the dam reservoir has increased comparing with pre
ex-post evaluation times, and it provides water continuously to the irrigation system downstream.
Facilities associated with the power plant that were constructed during the construction period have taken
part in the area development. There was no new adverse impact on natural environment and social
environment, with CEB’s monitoring efforts. Disputes over resettlement have not yet been resolved,
although the land acquisition and resettlement saw a great progress and CEB was expected tocontinuously work on this.
The Samanalawewa Hydroelectric Power Plant had enhanced its management by obtaining
ISO9001 and ISO 14001, allocation of technical personnel, and implementation of training programs.
Although CEB was not in a favorable financial condition, the Power Station is allocated with sufficientbudget for operation and maintenance. However, there were equipment and facilities that havedeteriorated over 20 years of operation.
CEB saw an abrupt increase of water leakage that occurred in 2006, but had operated the Power
Plant with special attention paid to safety. There were two surveys presently being conducted regarding
the water leakage, which had not reached final conclusion on the leakage mechanism and15

countermeasures. Long-term structural safety should thus be further sought.
4.2 Recommendations
4.2.1 Recommendations to the local administrative bodies and CEB(1) Rathnapura District and Divisional Secretariat Offices
It was recommended to continue working on the resettlement and CEB was required to monitor theactivities and progress.
(2) CEB
It is desirable to examine alternatives that are technically and economically viable and take necessary
actions to repair/replace deteriorated equipment and facilities.
With regard to the continuing water leakage on the right bank of the dam, no long-term safe solution
is secured yet. It is thus recommended to review the survey outcomes up to present, continue necessary
measurements, surveys and analyses, and examine concrete countermeasures.
4.2.2 Recommendations to JICA
It is recommended to correspond with CEB and monitor the progress of the survey and measures forleakage. Once if required, it is also recommended to take necessary action to the concerned organizations
and personnel.
4.3 Lessons Learned

Not applicable.

16Comparison of the Original and Actual Scope of the Project
Item

Plan

Actual(1) Outputs[Hydroelectric power plant]
Diversion tunnels (2) (JP)Dam (JP)[Hydroelectric power plant]
Length: 520 m and 545 m
Height: 103.5 m, Length: 529 m
Effective storage capacity: 254
million m3[Hydroelectric power plant]
Length: 482 m and 502 m
Height: 100 m, Length 530 m
Effective storage capacity: 218.2
million m3
Right bank cut-off works

Diversion tunnel (UK)
Hydroelectric turbines (JP)Power generator (UK)
Penstock (JP)Transmission line (other)

Length 5,150 m
Turbine discharge: 42.0 m3/s
120MW (60MW X2)
Length: 648 m
17 km (power station - Balangoda)

Length 5,159 m
As planned
As planned
Length: 670 m
19 km (power station - Balangoda)
39 km (power station Embilipitiya)[Remedial Works]
Main blanket (JP)Follow-up blanket (JP)[Remedial Works]
Input: 500,000 m3
Input: 500,000 m3[Remedial Works]
Input: 426,030 m3
Cancelled(2) Project Period[Hydroelectric power plant][Hydroelectric power plant][Hydroelectric power plant]

Sep 1986-Jul 1991 (59 months)

Sep 1986- Dec 1992 (76 months)[Remedial Works][Remedial Works]
Aug 1995–May 2001 (70 months)[Remedial Works]
Aug 1995–Jun 1999 (47 months)

Total
Japanese ODA loan portion
Exchange Rate

[Hydroelectric power plant]
43,139 million yen
17,037 million yen (2,433.8
million Rs)
60,176 million yen
28,420 million yen
1Rs= 7 yen (as of Apr 1986)[Hydroelectric power plant]
48,112 million yen
22,217 million yen (5,660 million
Rs)
70,329 million yen
31,684 million yen
1Rs= 3.93 yen (1986 - 1995)[Remedial Works]
Foreign Currency
Local Currency
Total
Japanese ODA loan portion
Exchange Rate

[Remedial Works]
5,061 million yen
1,153 million yen (568 million Rs)
6,214 million yen
5,282 million yen
1Rs= 2.03 yen (as of Feb 1995)[Remedial Works]
2,359 million yen
905 million yen (453 million Rs)
3,264 million yen
3,134 million yen
1Rs= 2.00 yen (1996-1999)(3) Project Cost
[Hydroelectric power plant]
Foreign Currency
Local Currency

17