Part 16 Hydrological Analysis for Masang-2 HEPPopen_jicareport.jica.go.jp/pdf/12037644_09.pdf ·...

Part 16 Hydrological Analysis for Masang-2 HEPP

Final Report (Supporting_Pre F/S) Part 16 Hydrological Analysis for Masang-2 HEPP

JICA Project for the Master Plan Study of 16-1 August, 2011 Hydropower Development in Indonesia

PART 16 HYDROLOGICAL ANALYSIS FOR MASANG-2 HEPP

16.1 METEOROLOGY AND HYDROLOGY

Meteorological Records and Hydrological Records are collected from Meteorological Climatological and Geophysical Agency (Badan Meteorologi Klimatologi dan Geofisika: BMKG), Research Institute for Water Resources Development under Ministry of Public Works (Pusat Penelitian dan Pengembangan Sumber Daya Air: PUSAIR, formerly DPMA), and engineering reports on various hydropower development projects. The location map of the stations is shown in Figure 1. The availability of data is summarized in Figure 2 and Figure 3. The catchment area of Masang-2 HEPP intake weir site is shown in Figure 4.

16.1.1 METEOROLOGICAL DATA

Climatic data such as air temperature, relative humidity, wind velocity, sunshine duration have been observed at the Tabing-Padang station, which is collected from BMKG. Pan-evaporation has been observed at the Lubuk Sikaping and the Tanjung Pati stations. Pan-evaporation data is collected from Masang-3 HEPP report.

The variation of principal climatic data at the Tabing-Padang station, the Tanjung Pati station and the Lubuk Sikaping station is shown in Figure 5.

(1) Air Temperature

Table 1 shows the monthly mean air temperature at the Tabing-Padang station. The average monthly mean air temperature at the Tabing-Padang station in the period of 1971 to 2002 is summarized below.

Unit: ℃Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean26.3 26.2 26.4 26.5 26.6 26.3 25.9 25.7 25.7 25.8 25.7 26.0 26.1

As seen, the mean annual air temperature at the Tabing-Padang station is 26.1ºC on an average. There is a slight seasonal change ranging 25.7ºC in August or September to 26.6ºC in May.

(2) Relative Humidity

Table 2 shows the monthly mean relative humidity at the Tabing-Padang station. The average monthly relative humidity at the Tabing-Padang station in the period of 1971 to



2002 is summarized below.

Unit: %Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean81.1 81.3 82.4 83.0 82.6 81.4 81.6 82.2 82.2 83.9 84.6 83.1 82.5

As well as the monthly pattern of mean air temperature, there is no significant change of relative humidity throughout the year. The annual mean relative humidity in the period of 1971-2002 at the Tabing-Padang station is 82.5 % and there is a slight seasonal change ranging from 81.1% in January to 84.6 % in November.

(3) Sunshine Duration

Table 3 shows the monthly mean sunshine duration at the Tabing-Padang station. The average monthly mean sunshine duration at the Tabing-Padang station in the period of 1971 to 2002 is summarized below.

Unit: %Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean53.1 57.4 53.3 55.3 59.5 61.7 60.9 55.4 42.9 41.7 40.4 50.7 52.7

As seen, the mean annual sunshine duration at the Tabing-Padang station is 52.7 % on an average. The maximum duration of 61.7 % and the minimum one of 40.4 % occur in June and November, respectively. Sunshine duration generally decreases with an increase of rainfall. The highest sunshine duration therefore occurs in June in the dry season.

(4) Wind Velocity

Table 4 shows the monthly mean wind velocity at the Tabing-Padang station. The average monthly mean wind velocity at the Tabing-Padang station in the period of 1971 to 2002 is summarized below.

Unit: m/secJan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean1.3 1.3 1.3 1.1 1.0 0.9 1.1 1.0 1.1 1.1 1.1 1.1 1.1

Mean annual wind velocity at the Tabing-Padang station is 1.1 m/sec ranging from 0.9m/sec in June and 1.3 m/sec in January, February or March. The wind velocity records collected from Masang-3 HEPP reports in the period of 1971 to 1989 are around 1 m/sec, but the others collected from BMKG in the period of 1990 to 2002 are around 0.1 m/sec.

(5) Evaporation

Pan evaporation records are available at the Lubuk Sikaping station and the Tanjung Pati station. The pan evaporation records at both stations are summarized on monthly basis as shown in Table 5. The average monthly mean pan evaporation at the Lubuk Sikaping and the Tanjung Pati stations is summarized below.



Station Name: Lubuk Sukaping (1979-1985) Unit: mm/dayJan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean4.8 4.4 4.3 3.9 3.7 4.1 4.1 4.2 3.6 3.6 3.9 4.1 4.1

Station Name: Tanjung Pati (1975-1985) Unit: mm/dayJan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean3.3 4.1 3.5 3.6 3.6 3.5 3.6 3.9 3.6 4.1 3.1 3.5 3.6

The ruling factors of pan evaporation may be air temperature and relative humidity, namely evaporation rate varies season to season following to mainly the variation of humidity. As seen in the above table, the seasonal variation of pan evaporation is generally small throughout the year, because there is no great seasonal variation of relative humidity.

16.1.2 RAINFALL DATA

There are 13 rainfall gauging stations in and around the Masang River basin. The location map of these stations is shown in Figure 1. Also the data availability at these stations is shown in Figure 2.

The rainfall gauging stations are operated and maintained under BMKG. Monthly rainfall records are collected in Masang-3 HEPP and HPPS2, besides daily rainfall records are collected from BMKG in this study.

PLN formerly had own hydrological observation network (PLN-LMK Observation Network). Currently most of these stations have broken down, after regional office of PLN took responsibility for maintenance which the central office of PLN had taken.

(1) Monthly Rainfall Data

The monthly mean rainfall records are collected at 13 stations as presented in Table 6 to Table 18.

The monthly distributions of mean annual rainfall are illustrated below.

Manin jau : 3 ,199 mm (1969-1993)

0

100

200

300

400

500

600

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Rai

nfa

ll(m

m)



Limau Purut : 3 ,491 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Padang Pan jang: 3 ,760 mm (1969-2002)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Bukit Tinggi : 2 ,021 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Baso : 2 ,012 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)



Padang Mangatas: 2 ,045 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Payakumbuh : 2 ,181 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Koto T inggi : 2 ,638 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Su l iki : 2 ,440 mm (1969-2007)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)



Kota Baharu : 2 ,828 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Bon jo l : 4 ,613 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Jambak: 3 ,797 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

Lubuk Sikaping: 3 ,760 mm (1969-1993)

0

100

200

300

400

500

600


Rai

nfa

ll(m

m)

As seen above, the annual mean rainfall at these stations ranges from 2,000 mm to 4,600 mm per year. It might be said that there exists little seasonality in the Masang River basin receiving rainfalls throughout the year.

(2) Hourly Rainfall Records

Hourly rainfall records are available at the Gunung Melintang, Maninjau, Sungai Talang



Barat, Solok Bio-Bio, Muara Paiti, Patir, Puar Datar and Halaban Dua rainfall gauging stations. The location map of the stations is illustrated in Figure 6.

Hourly rainfall records are collected to determine the rainfall pattern for the flood analysis. Hourly rainfall records of more than 50 mm were selected for estimating the characteristics of relatively heavy rainfall. The list of selected hourly rainfall records are enumerated in Table 19 and illustrated in Figure 7.

The accumulated hourly rainfall curves are constructed as shown in Figure 7. From these curves, the following findings on storm rainfall characteristics are drawn.

The duration of storm rainfall is less than 6 hours.

Most of the total amount of rainfall occurs in antecedent 3 hours.

16.1.3 RUNOFF RECORDS

(1) Water Level Gauging Station (AWLR Station)

Only one water level gauging station has been installed in the Masang River basin. The station name is the Sipisang AWLR station located in the north of Palembayan town. The catchment area of the station is described as 458 km2 in the records from 1975 to 1992, and as 436.4 km2 in the records from 1993to 2008. On this study, the catchment area of the station is measured as 475km2 based on 1:50,000 scale map. Besides, the catchment area of Masang-2 HEPP intake weir site is measured as 443km2.

The Sipisang AWLR station is operated by the regional office of the River Bureau under the Ministry of Public Works (Balai Pengendalian Sumber Daya Air: BPSDA).

(2) Runoff Records

The daily runoff records are collected from PUSAIR in Bandung and the daily water level records are collected from BPSDA in Bukit Tinggi. The daily runoff records are available from 1975 to 2008 except in 1988, 1989, 1994, 2002, 2003 and 2004. The monthly mean runoff at the Sipisang AWLR station is presented in Table 20. The daily hydrographs are illustrated in Figure 8 to Figure 14, and the daily water level graphs are illustrated in Figure 15 to Figure 16.

The average monthly mean runoff in the period of 1975-2008 is summarized below.

Station Name: Sipisang (1975-2008) Unit: m3/sJan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean22.4 20.0 21.6 23.8 22.5 18.7 16.8 18.1 20.6 21.4 27.7 29.2 21.9

As seen, the annual mean runoff at the Sipisang AWLR station is 21.9m3/s or 1,455mm in



terms of the annual runoff depth, which is computed by dividing the annual accumulated runoff volume by the catchment area of the gauging station.

16.1.4 LOWFLOW ANALYSIS

(1) General Approach

The continuous long-term runoff data for a time period of more than 20 years at the proposed intake weir site is normally required for evaluating an optimum development scale of the project through power output computation. Further, it is highly expected that the runoff data should be of high accuracy because measurement on economic viability of project is highly dependent on the reliability of available runoff records.

On the Masang-2 HEPP, daily runoff records are required because the type of hydropower development scheme is runoff type.

As described in the previous chapter, the daily runoff records are available from 1975 to 2008 except in 1988, 1989, 1994, 2002, 2003 and 2004. Furthermore, the remaining observation years still include data-missing periods. Therefore, it is necessary to supplement the runoff records at the Sipisang station by infilling of missing data.

On the other hand, the monthly basin mean rainfall at the Sipisang station can be estimated for the period between 1973 and 1993. Thus the runoff data at the Sipisang station can be supplemented and expanded for the period of 1973 to 1993 by constructing a rainfall-runoff simulation model.

Along this line, the Tank Model Method is applied in this study as a rainfall-runoff model, the model parameters of which are calibrated by using rainfall and runoff records available in the period of 1982 to 1986.

Firstly, the reliability of the available runoff records at the Sipisang station for using calibration is evaluated by means of runoff coefficient and annual rainfall loss. Then lowflow analysis by the Tank Model Method is carried out to simulate 21-year long-term monthly runoff data at the Sipisang station.

Finally the daily runoff data at the Masang-2 intake weir site is estimated with 14-year simulated monthly data and 7-year observed daily data.

The outline of lowflow analysis is described below.



(2) Estimation of Missing Data

The observed rainfall records at all of the selected stations include several data interruptions. For the purpose of supplementing the missing rainfall records, the simple regression analysis on the monthly basis are carried out among the selected stations. Missing data at a station is supplemented by another station with linear regression equation which has the highest correlation coefficient. The number of data and correlation coefficient and slopes of linear regression equation is tabulated in Table 21.

(3) Test of Consistency of Rainfall Records

The method of testing rainfall records for consistency is the double-mass curve technique. Double-mass analysis tests the consistency of the record at a station by comparing its accumulated annual or seasonal precipitation with the concurrent accumulated values of mean precipitation for a group of surrounding stations.

The corrected rainfall is determined by the following equation.

)/( aCXCX MMPP ×=

where, CXP : Corrected rainfall at any time period at station x (mm) XP : Original recorded rainfall at any time period at station x (mm) CM : Corrected slope of the double-mass curve aM : Original slope of the double-mass curve



The double-mass curves are presented in Figure 17. As seen, the monthly rainfall records at the following stations are adjusted for the following periods.

Maninjau Station: 1979 to 1993

Suliki Station: 1988 to 1993

(4) Estimation of Basin Mean Rainfall at the Sipisang AWLR Station

The basin mean rainfall at the Sipisang AWLR station is estimated by applying the Thiessen Method using the corrected data. The records of selected rainfall gauging stations are divided in two periods considering data availability.

Case1 (1973 to 1986): Maninjau, Koto Tinggi, Suliki

Case2 (1987 to 1993): Koto Tinggi, Suliki, Jambak

The tables below show the computed Thiessen coefficients for estimating basin mean rainfall at the the Sipisang AWLR station. Thiessen polygon is illustrated in Figure 18.

Case1 (1973-1986)Maninjau Koto Tinggi Suliki

0.67 0.23 0.10

Case2 (1987 to 1993)Koto Tinggi Suliki Jambak

0.74 0.21 0.05

The estimated monthly basin mean rainfall at the Sipisang AWLR station is presented in Table 22. The estimated annual basin mean rainfall is 2,507mm.

(5) Evaluation of Runoff Records at the Sipisang AWLR Station

The Sipisang AWLR station is selected as a key stream gauge station for predicting the long-term runoff at the proposed Masang-2 intake weir site, because it is the only gauge located in the Masang River. The evaluated period of runoff records is determined to be 5 years from 1982 to 1986, because both rainfall and runoff records are available in this period for calibration of Tank Model parameters.

1) Relationship between Annual Basin Mean Rainfall and Annual Runoff Depth at the Sipisang AWLR Station

The annual basin mean rainfall at the Sipisang AWLR station is estimated for the period of 1982 to 1986. On the other hand, the annual runoff depth of Masang River at the Sipisang station is computed by dividing the annual runoff volume by its drainage area of 475 km2 for the same period as above.

The established relationship between annual basin mean rainfall and annual runoff depth at



the Sipisang station is as follows. Besides, the relationship is plotted in Figure 19.

YearAnnual Rainfall

(mm)Annual Runoff

DepthAnnual Rainfall

LossRunoff

Coefficient1976 2,207 1,375 832 0.621982 2,430 1,253 1,176 0.521983 2,314 1,233 1,081 0.531984 3,339 1,318 2,022 0.391985 2,615 1,449 1,165 0.551986 3,029 1,450 1,579 0.481991 3,030 1,326 1,704 0.441993 3,027 2,101 925 0.69

Average 2,749 1,438 1,311 0.53

The difference between the annual basin mean rainfall and annual runoff depth is the so-called evapotranspiration loss or annual rainfall loss.

The annual rainfall loss is analyzed for major rivers in Sumatra in HPPS2 as presented in Table 23 and illustrated in Figure 20. It is therefore found that the annual rainfall loss normally falls in a range of 700 to 1,500 mm a year which varies according to altitude, natural vegetation, seasonal distribution of rainfall, etc.

As seen above, the rainfall loss at the Sipisang station varies from 800mm to 2,000mm. From the hydrological point of view, the rainfall loss usually varies in a small range. Therefore it is estimated that rainfall data or runoff data has some errors. The basin mean rainfall is adjusted based on the following consideration.

The annual runoff depth is likely to be constant rather than the basin mean rainfall, with small variations of 1,200 to 1,500 mm. The observed record in 1993 is eliminated because it might contain errors due to malfunctioning of water level recorder.

Maninjau, Koto Tinggi, Suliki, Jambak rainfall gauging stations which are used for estimating basin mean rainfall are located outside the Masang River basin. This fact implies that the estimated basin mean rainfall might inevitably contain some error to some extent.

The estimated annual basin mean rainfall in 1976, 1984 and 1991 are thus adjusted such that the annual rainfall loss becomes 1,251mm, which corresponds to the mean annual rainfall loss in 1982, 1983, 1985 and 1986.

The adjusted relationship between annual basin mean rainfall and annual runoff depth at the Sipisang station is given below.



YearAnnual Rainfall

(mm)Annual Runoff

DepthAnnual Rainfall

LossRunoff

Coefficient1976 2,626 1,375 1,251 0.521982 2,430 1,253 1,176 0.521983 2,314 1,233 1,081 0.531984 2,568 1,318 1,251 0.511985 2,615 1,449 1,165 0.551986 3,029 1,450 1,579 0.481991 2,577 1,326 1,251 0.511993 - - - -

Average 2,594 1,343 1,251 0.52

2) Double Mass Curve Analysis

Based on the adjusted annual basin mean rainfall and annual runoff depth at the Sipisang station, the double mass curve is constructed as given below.

-

5,000

10,000

- 5,000 10,000 15,000 20,000

Accumulated Basin Mean Rainfall (mm)

Accum

ula

ted R

unoff

Depth

(m

m)

1976

1991

1982

1983

1984

1985

1986

As shown above, the annual basin mean rainfall and annual runoff depth are plotted on a straight line, satisfactorily showing the hydrological consistency ready for Tank model analysis to be discussed in the next section.

(6) Tank Model

1) Concept of Tank Model Method

The Tank Model simulation method is widely applied for estimating river runoff from rainfall data. The Tank Model Method has been successfully applied for low-flow analysis in various water resources development projects in Indonesia.

Basic concept of Tank Model

The basic idea of Tank Model is very simple. Consider a tank having a hole at the bottom and another hole at the side as illustrated below.



When the tank is filled with water, the water will be released from the holes as shown in the above. In the tank model simulation, it is considered that the water released from the side hole corresponds to runoff from a stream, and the water from the bottom hole goes into the ground water zone.

The depth of water released from a hole is given by the following tank equation.

HQ ×=α

where, Q : Runoff depth of released water (mm)

α : Coefficient of hole H : Water depth above the hole (mm)

Applied Tank Model

For the purpose of natural runoff simulation, four by four (4×4) tanks combined in series are used as shown in Figure 21.

The top tank receives the rainfall as inflow to the tank, while the tanks below get the supply from the bottom holes of the tank directory above. The aggregated outflow from all the side holes of the tanks constitutes the inflow in the river course.

To effectively trace dry conditions in the basin, several modifications are made on the basic model. The model is firstly facilitated with a structure to simulate the moisture content in the top tank. This sub-model is composed of two moisture-bearing zones, which contain moisture up to the capacities of saturation. Between the two zones, the water transfers as expressed below.

)//(2 SSXSPSXPTCT −=

where, 2T : Transfer of moisture between primary and secondary zones (if positive, transfer occurs from primary to secondary, and vice versa) TC : Constant



XP : Primary soil moisture depth PS : Primary soil moisture capacity XS : Secondary soil moisture depth SS : Secondary soil moisture capacity

When the primary soil moisture is not saturated and there is free water in lower tanks, the water goes up by capillary action so as to fill the primary soil moisture with the transfer speed T1 as given below.

)/1(1 PSXPTBT −=

where, 1T : Transfer of the water from lower tank with capillary action TB : Constant

There are many tank model parameters such as hole coefficients of each tank, and height of side holes of each tank. These parameters cannot be determined mathematically. Therefore, these parameters are subject to determination through trial-and-error calculations comparing the calculated runoff with the actually observed runoff.

2) Input Data for Calibration Model

The applied model and simulation condition for calibration are given below. The period for calibration set from 1982 to 1986 because there are continuously rainfall records and runoff records.

Number of Tanks 4×4Calculation Time Interval 1 monthCalculation Period 1982 to 1986Observed Runoff at Sipisang Station 1982 to 1986Basin Mean Rainfall at Sipisang Station 1982 to 1986Monthly Average Evaporation at Lubuk Sikaping 1979 to 1985

The pan evaporation record at the Lubuk Sikaping station is applied. The pan coefficient of 0.7 is applied for estimating evapotranspiration in the basin. The average monthly pan evaporation is given below.

Station Name: Lubuk Sukaping (1979-1985) Unit: mm/dayJan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean4.8 4.4 4.3 3.9 3.7 4.1 4.1 4.2 3.6 3.6 3.9 4.1 4.1

3) Calibration Results

Through several trial-and-error calculations, the best coincidence between the simulated and observed runoff at the Sipisang station is obtained under the tank parameters as follows.



Hole Coefficient Height of Hole (mm)β α1 α2 H1 H2

Tank-1 0.300 0.350 0.350 15.0 30.0Tank-2 0.050 0.070 0.000 5.0 0.0Tank-3 0.010 0.030 0.000 2.0 0.0Tank-4 0.001 0.006 0.000 0.0 0.0

Both observed and simulated hydrographs are shown in Figure 22. These hydrographs show that the simulated runoff satisfactorily represents the observed low-flow-season runoff.

Furthermore, the consistency of the simulated runoff is examined by the comparison of flow duration curves constructed on the basis of the observed and simulated runoff. The flow duration curve for the runoff is drawn by arranging the discharges in descending order and assigning probabilities to each discharge, as illustrated in Figure 23.

Both flow duration curves coincide with each other, especially in the lowflow period. The error of the estimated runoff over 40 % in probability varies between 0.4 % and 4.2 %.

In addition to the above, the rainfall-runoff relationship of the simulated runoff is examined compared with the observed runoff as summarized below.

Observed Simulated Observed Simulated Observed Simulated

1982 2,430 1,254 1,203 1,177 1,227 0.52 0.50

1983 2,314 1,233 1,143 1,081 1,171 0.53 0.49

1984 2,635 1,314 1,241 1,321 1,395 0.50 0.47

1985 2,615 1,449 1,400 1,166 1,215 0.55 0.54

1986 3,029 1,450 1,697 1,579 1,332 0.48 0.56

Average 2,605 1,340 1,337 1,265 1,268 0.52 0.51

Runoff Coefficient

Year

AnnualRainfall(mm)

Annual Runoff Depth(mm)

Annual Rainfall Loss(mm)

As seen above, the average runoff coefficient and rainfall loss of the simulated runoff are derived to be 0.51 and 1,268 mm, respectively. On the other hand, hydrological indices of the observed runoff at the Sipisang station are 0.52 and 1,265 mm. These derived hydrological indices are judged to be in the hydrologically reasonable range.

(6) Prediction of the Long-Term Runoff at the Sipisang AWLR Station

The tank model with the calibrated parameters in the above is applied to generate the monthly runoff at the Sipisang station dating back to the period of 1973 to 1993 by use of the estimated monthly basin mean rainfall. The simulation results are summarized in Figure 24.

The rainfall-runoff relationship of simulated runoff is summarized below.



Observed Simulated Observed Simulated Observed Simulated1973 2,213 - 1,188 - 1,025 - 0.541974 2,622 - 1,255 - 1,367 - 0.481975 1,882 - 990 - 893 - 0.531976 2,208 1,371 848 836 1,360 0.62 0.381977 2,215 - 1,010 - 1,205 - 0.461978 2,203 - 1,071 - 1,132 - 0.491979 2,061 - 866 - 1,195 - 0.421980 2,252 - 919 - 1,333 - 0.411981 2,797 - 1,403 - 1,395 - 0.501982 2,430 1,254 1,377 1,177 1,053 0.52 0.571983 2,314 1,233 1,159 1,081 1,155 0.53 0.501984 2,635 1,314 1,245 1,321 1,390 0.50 0.471985 2,615 1,449 1,401 1,166 1,214 0.55 0.541986 3,029 1,450 1,697 1,579 1,332 0.48 0.561987 2,674 - 1,410 - 1,264 - 0.531988 2,231 - 1,292 - 939 - 0.581989 2,122 - 963 - 1,159 - 0.451990 2,516 - 1,184 - 1,333 - 0.471991 3,030 1,326 1,538 1,704 1,492 0.44 0.511992 2,874 - 1,821 - 1,053 - 0.631993 3,027 - 1,646 - 1,381 - 0.54

Average 2,474 - 1,251 - 1,222 - 0.50

Runoff CoefficientYearAnnualRainfall

(mm)

Annual Runoff Depth(mm)

Annual Rainfall Loss(mm)

As seen in the table, the average runoff coefficient and rainfall loss of the simulated runoff are derived to be 0.50 and 1,222 mm, respectively. These hydrological indices are judged to be within the hydrological reasonable range.

The monthly runoff data for the flow duration curve is consisted of 7-year observed monthly runoff in 1976, 1982 to 1986 and 1991, and of 14-year simulated monthly runoff in remaining period from 1773 to 1993. The flow duration curve for the 21-year runoff is drawn by arranging the discharges in descending order and assigning probabilities to each discharge. The flow duration curve of the observed and simulated runoff is shown in Figure 25.

(7) Daily Flow Duration Curve

For Masang-2 HEPP, daily runoff data is required for power output computation because the type of scheme is runoff type. Nevertheless, it is difficult to collect long-term daily rainfall and runoff data in Masang River basin and the monthly runoff records are supplemented and extended with Tank Model method. So the combination of daily observed runoff and simulated monthly runoff is used for setting the daily flow duration curve. The value of simulated monthly runoff data is regarded as simulated daily runoff in same amount.

The condition of data is summarized below.



Time Interval DailyObserved Daily Runoff 1976, 1982 to 1986, 1991Simulated Monthly Runoff 1973 to 1975, 1977 to 1981, 1987 to 1990, 1992, 1993

(8) Long-Term Runoff at the Masang-2 Intake Weir Site

The long-term daily runoff at Masang-2 intake weir site for 21 years in the period of 1973 to 1993 is estimated from the predicted long-term daily runoff at the Sipisang station by using the following equation. The flow duration curve as shown in Figure 26, is drawn by arranging the discharges in descending order and assigning probabilities to each discharge.

)/( WDWD AAQQ ×=

where, DQ : Runoff at Masang-2 intake weir site (m3/sec) WQ : Runoff at Sipisang AWLR station (m3/sec) DA : Catchment area at Masang-2 intake weir site (=443km2) WA : Catchment area at Sipisang AWLR station (=475km2)

(9) Water Level Observation and Discharge Measurement

The field investigation of 3 month water level observation and 30 times discharge measurement was carried out from 2010 October 6th to 2011 January 7th by the sub-contractor. Location of the observation is at the Masang-2 intake weir site (St.1) and the Sipisang AWLR station (St.2). The location map of observation is shown in Figure 27. H-Q rating curve is established on the basis of observed water level and discharge, and hydrograph is established on the basis of observed water level and H-Q rating curve. Hydrograph is illustrated in Figure 28 and H-Q plot is shown in Figure 29.

Consequently, the average water level is 0.75m and the average runoff is 23.85 m3/s calculated with H-Q rating curve. The Equation of H-Q rating curve is given below.

2)06.0(55.36 +×= HQ

where, Q : Runoff (m3/sec)

H : Water level (m)

The observed average runoff is about 15% of probability on the duration curve shown in Figure 26.

16.1.5 FLOOD ANALYSIS

(1) General Approach

Flood analysis is carried out to estimate the probable floods with various return periods as well as the probable maximum flood (PMF) at the Masang-2 intake weir site which are



basically required for design of spillway and diversion facilities, and determination of dam height.

For estimating the probable floods, the unit hydrograph method is applied, which synthesizes the various probable runoff hydrographs from the probable basin mean rainfalls based on the relationship between unit of basin mean rainfall and its runoff, that is the so-called unit hydrograph. It is generally agreed that the unit hydrograph method is applied for catchment areas less than 3,000 km2.

In this study, the Soil Conservation Service (SCS) unit hydrograph, which is empirically developed in USA Department of the Interior is used, because no hourly flood hydrograph is available at the Sipisang AWLR station to construct the unit hydrograph.

The general approach of flood analysis is outlined below.

(2) Rainfall Analysis

1) Depth-Area-Duration (DAD) Analysis

DAD analysis is carried out to examine the following relationships.

Relationship between rainfall depth and duration (DD Analysis)

Relationship between rainfall depth and area (DA Analysis)



a) Depth-Duration (DD) Analysis

Generally, heavy rainfall occurs intensively in a short duration and sporadically in a limited area. Figure 7 shows the accumulated hourly rainfall curves of selected rain storms at the stations located around the Masang River basin. Hourly rainfall records exceeding 50 mm within 12 hours were selected for estimating the hourly rainfall hyetograph of heavy storm rainfall which might cause flood.

The rainfall duration of selected 63-storm rainfall is arranged as histogram in Figure 30. Among the storm rainfalls bigger than 50mm, 6-hour of rainfall duration covers 63% of all. Besides, 6-hour of rainfall duration covers 80% of all among the storm rainfalls bigger than 100mm. So, the design rainfall duration time is estimated as 6-hour, which represents the characteristics of the storm rainfalls in Masang River basin.

40 of selected 63-storm rainfall have smaller duration time than 6-hours. The average of the

40 storm rainfalls is estimated as the design rainfall pattern. The accumulated hourly rainfall

curves and the design rainfall curve are presented in Figure 31.

The design distribution of hourly rainfall is shown below.

Time (hour) 0 1 2 3 4 5 6Cumulative Rainfall Depth 0% 47% 78% 87% 95% 99% 100%Incremental Rainfall Depth 0% 47% 31% 9% 8% 4% 1%

b) Depth-Area (DA) Analysis

Generally, heavy rainfall occurs intensively in a short duration and sporadically in a limited area. Therefore the average depth of storm rainfall (basin mean rainfall) is likely to be smaller than the point depth of storm rainfall.

In general, relation between point rainfall depth and average area is expressed by an exponential equation given by the following equation.

]exp[0n

b kAPP −×=

where, bP : Average rainfall depth over an area A (mm) 0P : Maximum point rainfall at the storm center (mm)

A : Area in question (km2) nk, : Constants for a given area

The above equation is the so-called Horton’s Equation. Constants k and n usually vary according to the given rainfall duration such as 1 hour, 6 hours, 12 hours, 1 day, etc. These constants are to be obtained through rainfall analysis based on the isohyetal maps of various major rain storms occurred in the river basin in question. However, the exact determination of 0P is practically impossible, because it is very unlikely that the rain storm center



coincides with a rainfall gauging station.

To estimate the basin mean rainfall from the point rainfall, the area reduction factor showing the ratio of basin mean rainfall to point rainfall is introduced as expressed below.

0PfP ab ×=

where, bP : Basin mean rainfall (mm) 0P : Point rainfall (mm) af : Area reduction factor

If the Horton’s equation is applied, the area reduction factor under the given rainfall duration is given by the following equation.

]exp[ na kAf −=

However the available rain storm records in the Masang River basin are insufficient for reliable determination of the area reduction factor. The preliminary estimation of the design area reduction factor is carried out based on the following three approaches.

Firstly, the area reduction factor is estimated as 0.63 under the catchment area of 443 km2 for the Masang-2 intake weir site by applying the Horton’s equation assuming that constants of k and n are 0.1 and 0.25, respectively. These constants have been widely and empirically applied in tropical rain forest area.

A 443 (km2)k 0.1n 0.25fa 0.63

Secondly, the estimated design area reduction factors are examined in several other projects. The following design area reduction factors are based on the rainfall analysis using the observed rain storm records.

Project Name Catchment Area(km2)

Area ReductionFactor

Besai HEPP (D/D in 1990) 415 0.50Malea HEPP (F/S in 1984) 1,463 0.45Tampur-1 HEPP (F/S in 1984) 2,000 0.40Musi HEPP (F/S in 1984) 586 0.50Cibuni-3 (F/S in 1984) 1,000 0.41Masang-3 HEPP (Pre F/S in 1999) 993 0.50

Thirdly, the relation between the daily point rainfall and the daily basin mean rainfall around the Masang River basin is analyzed to estimate the area reduction factor of the river basin. The selected rainfall stations are the Payakumbuh and Maninjau stations. A basin mean



rainfall derives from an arithmetic average of an annual maximum daily rainfall of a target station and daily rainfall of another station at the same day. The average of ratios between basin mean rainfalls and annual maximum daily rainfalls of target stations is estimated as the area reduction factor. The list of rainfall is presented in Table 24 and plotted on Figure 32.

Usually, it is considered that the rainfall intensity in hyetal areas increases with the depth of point rainfall. However, the area reduction factor showing the ratio of area rainfall to the maximum point rainfall varies from 0.5 to 0.8 for the area rainfall amount. Further, the area reduction factor does not always increase with the enlargement of the point rainfall. On the other hand, the design area reduction factors examined in several hydropower projects varies from 0.4 to 0.5.

In due consideration above, the design area reduction factor is conservatively determined to be 0.50.

2) Probable Point Rainfall

Out of the available rainfall records around the Masang River basin, the annual maximum 1-day rainfall records are available at the Payakumbuh rainfall gauging station as presented in Table 25. As seen in this table, the rainfall records at the Payakumbuh station have recording periods between 1951 and 1993 with some interruptions in recording.

The probable point rainfalls at the station with several return periods are estimated through frequency analysis using the Gumbel and Log Normal distributions as summarized below. The estimated frequency curves of probable daily rainfall at these stations are also presented in Figure 33.

Gumbel LN400 263 319 291200 242 281 261150 233 266 249100 220 245 233

80 213 235 22450 199 213 20630 183 190 18620 170 173 17110 148 145 146

5 125 119 1223 106 100 1032 90 85 87

Return Period(years)

Probable Point Rainfall (mm) Average

The probable point rainfall is estimated as the average of the probable rainfalls by the Gumbel and Log Normal distributions, because the estimated frequency curves by the Gumbel and Log Normal distributions have similar shapes.



3) Probable Maximum Precipitation (PMP)

Generally three (3) approaches are used for estimating the probable maximum precipitation (PMP) as follows.

Meteorological (theoretical) approach in consideration of the upper physical limit of moisture source

Statistical approach which is empirically developed by Dr. Hershfield from the rainfall records in the United States of America

Historical approach by examining the historical maximum one over occurred in the area of interest

The available basic climatological data such as dew point, humidity, wind velocity in Masang-2 catchment area for the first meteorological approach are insufficient for the time being. Further, no historical rain storm records are also so far available.

Therefore, PMP is estimated by the simple statistical Hershfield method using a series of the annual maximum daily rainfall records. This method is widely applied in the basin where rainfall records are available but other basic climatological records are hardly obtainable.

The Hershfield’s equation is expressed as follows.

nmnm SKXX ×+=

where, mX : Extreme value of 24-hour rainfall (PMP) (mm) nX : Adjusted mean annual maximum rainfall (mm) mK : Statistical coefficient nS : Adjusted standard deviation of a series of annual maximum rainfall

As seen in the above equation, PMP in question is assumed to be given as the adjusted mean annual maximum rainfall in question plus the Km times the standard deviation of a series of annual maximum rainfall in question.

The PMP is estimated by applying a series of annual maximum rainfall in the Masang river basin. The calculation process is as follows.

Computation of Statistical Parameters

The mean annual maximum rainfall (Xn) and its standard deviation (Sn) are calculated to be 96.1 mm and 47.1 mm, respectively.

Concurrently with the above, Xn-m and Sn-m are estimated at 91.6 mm and 38.2 mm, which are computed after excluding the maximum rainfall in the series of rainfall data. These statistical



parameters are used for several adjustment necessary computing Xn and Sn.

Adjustment of Xn and Sn for Maximum Observed Event

The adjustment factors of Xn (fx1) and Sn (fs1) for the maximum observed rainfall shall be obtained from the Hershfield’s adjustment curves as shown in Figure 34 and Figure 35.

Applying the values of Xn, Xn-m, Sn and Sn-m, adjustment factors are obtained 97 % for fx1 and 89 % for fs1, respectively.

Adjustment of Xn and Sn for Sample Size

The adjustment factors of Xn (fx2) and Sn (fs2) for the length of record shall be obtained from the adjustment curves as presented in Figure 36.

The obtained factors of fx2 and fs2 are 100.5 % and 101.6 %, respectively.

Statistical Coefficient Km

The statistical coefficient Km shall be obtained from the empirical Km curves as presented in Figure 37. Applying the mean annual maximum rainfall at the Payakumbuh station (Xn) is 96.1 mm, the Km value is obtained to be 15.5.

Adjustment for Fixed Observational Time Intervals

Rainfall observation has been carried out on the daily basis at the Payakumbuh station. Since the recorded daily rainfall is computed based on the single fixed observation time interval (say 8 a.m to 8 p.m), the PMP value yielded by the statistical procedure should be increased multiplying by the adjustment factor (fo).

The adjustment factor curve is presented by Dr. Hersfield as shown in Figure 38. Applying that the number of observation units is equal to 1, the fo value is obtained to be 113 %.

Computation of PMP at the Payakumbuh Station

The adjustment mean annual maximum rainfall (Xn) is finally given as follows.

nXXn XffX ××= 21

In addition, the adjusted standard deviation of a series of annual maximum rainfall (Sn) is given as follows.

nSSn SffS ××= 21

The unadjusted point PMP (Xm) is computed as follows.



nmnm SKXX ×+=

Finally, the point PMP is adjusted using the adjustment factor fo as follows.

mO XfPMP ×=

The computation process of the point PMP is summarized in Table 26. As seen, the point PMP at the Payakumbuh station is estimated to be 852 mm.

4) Basin Mean Rainfall

Applying the design area reduction factor of 0.5, the probable basin mean 1-day rainfalls with various return periods as well as PMP at the Masang-2 intake weir site are estimated as follows.

PMP 426400 146200 131150 125100 117

80 11250 10330 9320 8610 73

5 613 522 44

Probable Rainfall(mm)

Return Period(years)

(3) Hydrograph Analysis

1) Unit hydrograph

Since no flood hydrographs are available for the present flood analysis, the unit hydrograph is developed by means of the SCS (Soil Conservation Service) synthetic hydrograph method. The SCS method was developed by analyzing a large number of basins with varying geographic locations. Unit hydrographs were evaluated for a large number of actual watersheds and then made dimensionless by dividing all discharge ordinates by the peak discharge and the time ordinates by the time to peak. An average of these dimensionless unit hydrographs was computed.

a) SCS Unit Hydrograph

The SCS unit hydrograph is derived from the flood concentration time and unit basin rainfall. The unit hydrograph is constructed for a unit rainfall of 1 mm.

The peak discharge of the unit hydrograph is calculated as follows.



pp tAQq /208.0=

where, pq : Peak discharge (m3/sec)

A : Basin area (km2) Q : Total volume of the unit hydrograph (=1mm) pt : Time to peak (hours)

SCS has determined that the time to peak ( pt ) and rainfall duration ( D ) are related to time

of concentration ( ct ) as follows.

3/2 cp tt ×=

ctD 133.0=

b) Flood Concentration Time

The flood concentration time is defined as the time of travel from the most remote point in the catchment to the forecast point. The flood concentration time can be estimated by the formula of Kirpich as follows.

385.077.097.3 −××= SLtc

where, ct : Flood concentration time (min)

L : Maximum length of travel of water (km) S : Average slope (=H/L, where H is the difference in elevation between the remotest point in the basin and the outlet)

c) SCS Unit Hydrograph Calculation

With a maximum length of travel ( L ) of 49km, the concentration time ( ct ) was found to be about 6.2 hours. With a catchment area ( A ) of 443 km2, the peak flow ( pq ) is found to be

22.3 m3/sec/mm. The average slope of the Masang River is illustrated in Figure 39. The SCS unit hydrograph for the Masang River basin is shown in Figure 40.

A 443 km2

Q 1 mmL 49.156 kmtc 6.2 hoursqp 22.3 m3/s/mmtp 4.1 hours



2) Probable Flood Hydrograph at Masang-2 Intake Weir Site

The probable flood hydrographs including PMF at the Masang-2 intake weir site are derived by convolution of the probable basin mean rainfall, PMP with the design rainfall hyetograph and the unit hydrograph.

The base flow is determined to be 14 (m3/s) from the average rainy-season discharge records at the Sipisang AWLR station, and the rainfall loss is assumed to be 47 %. The daily hydrograph is shown in Figure 41, and the rainfall loss is presented in Table 28.

The computed probable flood hydrographs as well as PMF are presented in Table 29 and shown in Figure 42.

The probable design flood discharges with various return periods together with PMF are collected from various hydropower projects in Sumatra as presented in Table 30.

3) Creager’s Coefficient for Probable Floods at Masang-2 Intake Weir Site

Creager’s coefficient for probable flood is computed by the following equations.

ap ACQ )3861.0()02832.046( ××××=

048.0)3861.0(894.0 −×= Aa

where, pQ : Peak discharge of probable flood (m3/sec)

C : Creager’s coefficient A : Catchment area (km2)

The Creager’s coefficients corresponding to the various return periods and PMF for the Masang-2 HEPP are enumerated in the table below.

T Q C(year) (m3/s)

PMF 4344 92400 1493 32200 1341 28150 1280 27100 1198 25

80 1152 2450 1061 2230 959 2020 883 1910 756 16

5 634 133 537 112 456 10

Figure 43 and Figure 44 shows the relationship between probable flood peak discharges with return periods of 2, 20, 100, 200 years as well as PMF and catchment area for the Masang-2



HEPP and other water resources development projects in the whole Sumatra. The Creager’s curves are illustrated using the Creager’s coefficients of the Masang-2 intake weir site calculated in above. The probable floods at the Masang-2 HEPP are well plotted in reasonable range of design floods in Sumatra.

4) Probable Floods at the Masang-2 Regulating Pond Site

The time of concentration ( ct ) at the Masang-2 Regulating Pond is calculated as 0.17 hour

with the same method as the Masang-2 intake weir site. Probable floods at the Masang-2 Regulating Pond are estimated with the Creager’s coefficients of the Masang-2 intake weir site, because short time interval rainfall records like 10-minutes do not exist in Masang River basin. The catchment area of the Masang-2 intake weir site is illustrated in Figure 46.

A 1 km2

L 1.3 kmtc 0.17 hours

The results of flood analysis are estimated as follows.

PondT Q C Q

(year) (m3/s) (m3/s)PMF 4344 92 49.1400 1493 32 16.9200 1341 28 15.2150 1280 27 14.5100 1198 25 13.5

80 1152 24 13.050 1061 22 12.030 959 20 10.820 883 19 10.010 756 16 8.6

5 634 13 7.23 537 11 6.12 456 10 5.2

Intake

5) Probable Floods at the Masang-2 Power House Site

The Alahanpanjang River and the Masang River join together at the upstream of the Masang-2 Power House site. At the power house site, probable floods seem to be controlled by floods from the Masang River, because the catchment area of the Alahanpanjang River basin is smaller than the Masang River basin. So, Probable floods at the Masang-2 power house site are estimated with the Creager’s coefficients of the Masang-2 intake weir site as same as the regulating pond. The catchment area of the power house site is 919.5km2, illustrated in Figure 47.

The results of flood analysis are estimated as follows.



PHT Q C Q

(year) (m3/s) (m3/s)PMF 4344 92 6281.3400 1493 32 2158.8200 1341 28 1939.1150 1280 27 1850.9100 1198 25 1732.3

80 1152 24 1665.850 1061 22 1534.230 959 20 1386.720 883 19 1276.810 756 16 1093.2

5 634 13 916.83 537 11 776.52 456 10 659.4

Intake

(4) Water Level Observation and Discharge Measurement

As mentioned in the chapter of lowflow analysis, the field investigation of 3 month water level observation and 30 times discharge measurement was carried out from 2010 October 6th to 2011 January 7th by the sub-contractor.

Consequently, the maximum water level is 2.01m and the maximum runoff is 156.61 m3/s calculated with H-Q rating curve in extrapolation. The Equation of H-Q rating curve is given below.

2)06.0(55.36 +×= HQ

where, Q : Runoff (m3/sec)

H : Water level (m)

16.1.6 SEDIMENT ANALYSIS

(1) General

Sedimentation analysis is preliminarily carried out to estimate the denudation rate in the Masang River basin. The sedimentation load is herein predicted based on the estimated runoff and the sediment discharge rating curve at the intake weir site. The rating curve is established based on the in-situ sampling records obtained through the field investigation conducted in the course of the study. The field investigation was carried out at the Masang-2 intake weir site and Sipisang AWLR station.

The sediment transport in the Masang River is judged to be higher than other rivers in the Sumatra. The denudation rate showing the expected average annual erosion rate in a river basin is generally influenced by the topography (soil condition, river gradient), deforestation of the land in the basin, rainfall intensity, etc.

In addition, the design denudation rates adopted in other water resources or hydropower



development projects in Sumatra are collected for comparison purposes.

(2) Suspended Load Sampling

A total of thirty (30) suspended load samplings were carried out at the intake weir site where discharge measurements were taken. The samples were taken to a laboratory for further analysis. The sieve analysis results of samples are shown in Figure 48.

(3) Suspended Load Rating Curve

The laboratory analysis results of the samples show the total suspended sediment concentration which is the combination of both dissolved and undissolved sediment. The total suspended load is found from the following formula.

WS QCQ ××= 0864.0

where, SQ : Suspended load (ton/day)

C : Total suspended sediment concentration (mg/L) WQ : Flow discharge (m3/s)

The suspended load calculations using the above formula are presented in Table 31. Several results are considered unreliable because they show very low concentration or very high concentration. Therefore these unreliable results will not be used in the determination of the suspended load rating curve. The values of Qs are plotted against their respective Qw values to determine the suspended load rating curve. On the basis of the estimated sediment discharge at the intake weir site, the suspended load rating curve is established as shown in Figure 49. The rating curve equation is given below.

7812.14615.5 WS QQ ×=

If the flow discharge Qw is known, the suspended load sediment Qs can be estimated.

(4) Total Sediment Load

The annual suspended load sediment yield is simulated by applying the above rating curve to the simulated daily runoff at the intake weir site. The catchment area of the Masang-2 intake weir site is 443km2.

Substituting runoff data, the average annual suspended load sediment at the intake weir site is estimated at 369,749 ton.

The density of sediment in appearance can be calculated by the following equation.

γγ ×−=′ )1( V

where, γ ′ : Density of sediment (ton/m3)



V : Void ratio of sediment γ : Unit weight of sediment (=2.65ton/m3)

Assuming a void ratio of 60 % in sedimentation, the density of sediment is found to be 1.06 ton/m3. Hence, the annual suspended load sediment is estimated at 348,820 m3.

The sediment load transport into an intake weir generally consists of suspended load and bed load. It is generally accepted that it might be difficult to accurately measure the bed load in a natural river. Usually, the rate of bed load transport is empirically estimated at 10 to 30 % of the total suspended load. The rate of bed load transport is estimated as 10% of the total suspended load, because 10% is usually applied in Indonesia.

Consequently, the mean annual sediment inflow volume into the Masang-2 intake weir is estimated to be 383,702 m3, which is equivalent to a denudation rate of 0.87 mm per year.

For comparison purpose, design denudation rates of various schemes around the project site are presented in the following table.

Project Name Project Stage Province Catchment Area Denudation Rate(km2) (mm/year)

Masang-3 Pre-F/S W. Sumatra 993 0.50Bt. Tonggar W. Sumatra 320 0.45Bt. Bayang-1 Pre-F/S W. Sumatra 84 0.70Bt. Bayang-2 Pre-F/S W. Sumatra 36 0.70Kotapanjang D/D Riau 3,337 0.50Kampar River Basin F/S Jambi - 0.50Upper Indragiri River Basin Jambi - 0.59Middle Indragiri River Basin Jambi - 0.53Merangin-2 D/D Jambi 1,309 0.34Merangin-5 Pre-F/S Jambi 2,597 0.70Lake Kerinci Jambi 1,053 0.72Source: Masang-3 HEPP, 1999.

As seen in the above table, the design denudation rates vary from 0.34 to 0.72 mm/year. The assumed denudation rate of 0.87 mm/year at the Masang-2 intake weir site might not be in the appropriate range.

Referring to the geology report in this study, there is place of gravel pit in the upstream of Masang River, and gravel extraction is seems to be carried out frequently. The samples of suspended load might be influenced by the gravel extraction. The gravel extraction might not be continuously carried out, so the design denudation rate of the Masang-2 intake weir should be estimated without influence of the gravel extraction in upstream. Nevertheless, it is difficult to estimate the volume of sediment yield from the gravel pit.

The grain size distributions of the samples are consists of mainly fine size grain smaller than 0.1mm, of which falling velocity is slow. It is estimated that the fine size grain has small influence to the sedimentation in the intake weir.



Consequently, the design denudation rate of the Masang-2 intake weir is estimated as 0.5mm/year which is the middle of design denudation rates in other projects. The design annual sediment inflow volume into the Masang-2 intake weir is estimated to be 221,500m3/year.

16.1.7 WATER QUALITY ANALYSIS

Water quality is important because it is linked to the availability of water for various uses. Specifically, for the Masang-2 HEPP it is important for the well being of hydraulic machinery, other equipment and hydraulic structures used in the project.

The laboratory test for water quality was carried out through the field investigation under the current study to identify the content of various chemical elements contained in the water in the Masang River. Water sampling is carried out three (3) times in total at the Masang-2 intake weir site. The samples were taken to a laboratory for further analysis.

The laboratory test results are presented in Table 32. The table shows that the pH of the water in the Masang River is around 8. It is therefore judged that the water in the Masang River will have no adverse effect on turbine and metal for hydropower use, because adverse effect is expected to occur under the pH value smaller than 4.5.


JICA Project for the Master Plan Study of T-1 August, 2011 Hydropower Development in Indonesia

Table 1 Monthly Mean Air Temperature

Station Name: Tabing-PadangElevation: 2.0m Unit: ℃

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average1971 26.1 26.0 25.7 26.2 26.4 26.1 25.8 25.2 25.6 25.4 25.0 25.0 25.71972 25.6 25.7 25.9 26.0 26.3 26.3 25.9 25.7 25.8 25.8 26.0 26.2 25.91973 26.5 26.8 26.2 26.4 26.5 26.2 25.9 25.6 25.4 25.4 25.7 25.2 26.01974 26.2 25.7 25.9 25.8 25.9 25.7 25.7 25.8 25.1 25.3 25.8 25.7 25.71975 25.5 25.6 25.9 26.2 26.3 25.7 25.1 25.5 25.4 25.4 25.3 25.3 25.61976 25.5 25.7 26.1 26.1 26.3 25.5 26.4 25.4 25.7 25.5 25.5 25.8 25.81977 26.1 25.7 26.6 26.7 26.4 26.3 25.9 25.8 26.0 25.8 25.7 26.1 26.11978 26.1 26.2 26.5 26.5 26.7 26.2 25.8 26.0 25.5 25.8 25.9 26.1 26.11979 26.6 26.0 26.5 26.5 26.4 26.1 25.2 25.6 25.7 26.1 25.7 26.5 26.11980 26.1 26.3 26.1 26.0 26.8 26.4 25.8 25.5 25.7 25.6 25.9 25.8 26.01981 - 26.1 27.1 26.5 - 26.5 25.7 25.7 25.5 25.5 25.5 26.1 26.01982 25.6 25.7 25.9 26.3 26.3 26.0 25.7 25.4 25.2 - 25.8 26.2 25.81983 26.9 26.9 27.5 26.9 26.6 - 26.2 26.0 26.0 25.9 26.0 25.7 26.41984 25.6 25.7 25.9 25.9 26.3 26.0 26.0 25.4 - 25.6 25.5 25.4 25.81985 26.0 25.8 26.0 26.1 26.3 25.3 25.1 25.8 25.3 26.0 25.6 26.3 25.81986 26.1 26.2 25.5 26.4 26.4 26.1 25.3 25.4 25.6 25.5 25.4 26.2 25.81987 26.8 26.3 26.5 25.6 26.6 26.8 25.9 26.1 26.0 26.0 25.9 26.3 26.21988 26.2 26.0 26.3 26.8 26.7 26.0 26.0 25.4 25.4 26.0 25.2 26.3 26.01989 26.4 26.1 - 26.6 26.8 - 25.5 - 25.9 25.9 26.0 26.3 26.21990 26.1 26.9 27.0 26.7 26.6 26.2 - 25.9 25.9 26.0 26.0 26.1 26.31991 26.3 26.5 26.8 26.3 26.8 26.6 26.3 25.9 26.1 25.8 25.4 26.1 26.21992 26.7 26.6 26.9 26.9 26.5 26.5 26.0 26.0 25.6 25.9 26.0 26.0 26.31993 26.0 26.5 26.0 26.5 26.4 26.8 26.2 25.8 25.8 26.0 26.0 26.2 26.21994 26.3 26.4 26.3 26.9 26.9 26.5 26.0 25.5 24.9 25.4 26.0 26.2 26.11995 26.7 - 27.7 27.0 26.9 26.9 26.3 - 26.4 26.2 - 25.9 26.71996 - 26.4 - - - 26.5 25.8 25.8 - - 26.1 25.7 26.01997 26.6 - 27.2 26.5 - 26.7 - 25.8 25.6 - - 26.2 26.41998 27.2 27.3 27.5 27.8 27.9 27.0 26.8 26.1 26.1 26.3 26.1 26.0 26.81999 26.0 26.5 26.7 26.9 26.4 26.4 25.8 25.9 26.0 25.9 25.9 26.2 26.22000 26.6 26.7 26.1 26.5 26.7 26.6 26.0 25.8 25.7 26.1 26.2 26.6 26.32001 - - - - - - - - - - - - -2002 27.1 - - - - - - - - - - - 27.1Min 25.5 25.6 25.5 25.6 25.9 25.3 25.1 25.2 24.9 25.3 25.0 25.0Max 27.2 27.3 27.7 27.8 27.9 27.0 26.8 26.1 26.4 26.3 26.2 26.6Ave 26.3 26.2 26.4 26.5 26.6 26.3 25.9 25.7 25.7 25.8 25.7 26.0 26.1

Source: (1971-1989) Masang-3 HEPP Report, 1999 (1990-2002) BMKG



Table 2 Monthly Mean Relative Humidity

Station Name: Tabing-PadangElevation: 2.0m Unit: %

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average1971 81.0 80.0 81.0 82.0 79.0 79.0 79.0 85.0 84.0 84.0 86.0 86.0 82.21972 82.0 84.0 82.0 86.0 86.0 84.0 84.0 83.0 85.0 84.0 85.0 84.0 84.11973 80.0 81.0 84.0 85.0 83.0 82.0 82.0 82.0 83.0 84.0 82.0 83.0 82.61974 81.0 80.0 82.0 84.0 83.0 83.0 81.0 82.0 86.0 82.0 83.0 83.0 82.51975 83.0 84.0 83.0 84.0 82.0 82.0 84.0 82.0 83.0 83.0 84.0 83.0 83.11976 81.0 84.0 82.0 83.0 82.0 84.0 84.0 82.0 84.0 86.0 85.0 83.0 83.31977 83.0 80.0 82.0 84.0 83.0 80.0 81.0 81.0 82.0 86.0 85.0 85.0 82.71978 82.0 82.0 84.0 82.0 82.0 80.0 81.0 81.0 81.0 83.0 84.0 84.0 82.21979 82.0 83.0 81.0 82.0 81.0 83.0 84.0 83.0 84.0 84.0 85.0 81.0 82.81980 81.0 81.0 82.0 86.0 81.0 80.0 82.0 83.0 82.0 83.0 84.0 81.0 82.21981 - 83.0 83.0 82.0 - 80.0 82.0 80.0 85.0 85.0 83.0 83.0 82.61982 83.0 85.0 84.0 85.0 85.0 82.0 83.0 83.0 84.0 - 89.0 86.0 84.51983 81.0 85.0 84.0 84.0 84.0 - 83.0 83.0 85.0 84.0 82.0 85.0 83.61984 79.0 80.0 85.0 84.0 83.0 82.0 84.0 81.0 - 83.0 87.0 84.0 82.91985 80.0 82.0 82.0 83.0 82.0 81.0 81.0 82.0 40.0 83.0 84.0 83.0 78.61986 83.0 80.0 86.0 84.0 83.0 84.0 82.0 84.0 83.0 85.0 84.0 84.0 83.51987 83.0 83.0 84.0 85.0 86.0 83.0 84.0 85.0 86.0 89.0 87.0 84.0 84.91988 86.0 84.0 87.0 86.0 84.0 84.0 82.0 87.0 88.0 86.0 88.0 77.0 84.91989 77.0 78.0 - 78.0 81.0 - 80.0 - 83.0 84.0 85.0 81.0 80.81990 80.7 80.2 80.9 82.0 80.6 81.1 - 78.6 82.4 84.8 83.9 83.1 81.71991 83.1 81.3 - 83.4 85.1 80.4 81.2 81.5 82.4 83.8 86.1 84.6 83.01992 78.3 78.9 82.8 82.4 84.4 80.1 81.2 81.8 82.6 79.7 82.8 82.6 81.51993 80.5 80.0 82.5 82.4 84.4 78.9 81.9 81.1 83.3 83.3 84.4 82.2 82.11994 83.2 80.7 82.5 81.8 81.5 81.9 78.2 81.0 83.0 85.1 87.1 83.9 82.51995 79.1 - 80.6 81.9 81.6 79.5 79.6 - 82.3 81.0 - 81.4 80.81996 - 79.4 - - - 82.1 79.7 80.3 - - 81.8 82.2 80.91997 76.8 - 77.5 83.2 - 81.0 - 81.5 84.6 - - 85.5 81.51998 82.9 83.2 - 83.2 81.6 80.7 79.3 82.6 83.8 81.7 83.7 83.9 82.41999 84.0 81.1 80.4 78.2 82.0 80.0 79.7 81.8 83.2 83.1 83.8 81.7 81.62000 78.7 73.0 77.9 80.8 79.5 79.9 80.6 81.9 85.4 83.8 84.5 81.3 80.62001 - - - - - - - - - - - - -2002 76.8 - - - - - - - - - - - 76.8Min 76.8 73.0 77.5 78.0 79.0 78.9 78.2 78.6 40.0 79.7 81.8 77.0Max 86.0 85.0 87.0 86.0 86.0 84.0 84.0 87.0 88.0 89.0 89.0 86.0Ave 81.1 81.3 82.4 83.0 82.6 81.4 81.6 82.2 82.2 83.9 84.6 83.1 82.5




Table 3 Monthly Mean Sunshine Duration

Station Name: Tabing-PadangElevation: 2.0m Unit: %

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average1971 - - - 45.0 36.0 29.0 26.0 22.0 19.0 25.0 15.0 27.0 27.11972 46.0 34.0 26.0 29.0 40.0 42.0 40.0 40.0 20.0 10.0 9.0 35.0 30.91973 56.0 61.0 47.0 39.0 53.0 57.0 65.0 43.0 34.0 47.0 44.0 38.0 48.71974 37.0 55.0 65.0 63.0 43.0 56.0 63.0 50.0 42.0 38.0 40.0 50.0 50.21975 50.0 47.0 54.0 52.0 69.0 60.0 61.0 68.0 55.0 50.0 46.0 48.0 55.01976 59.0 63.0 50.0 54.0 74.0 59.0 66.0 71.0 51.0 40.0 36.0 57.0 56.71977 57.0 44.0 66.0 55.0 68.0 64.0 61.0 58.0 42.0 40.0 44.0 62.0 55.11978 40.0 58.0 53.0 57.0 49.0 51.0 56.0 54.0 42.0 52.0 45.0 42.0 49.91979 66.0 51.0 69.0 45.0 61.0 56.0 53.0 56.0 52.0 43.0 37.0 68.0 54.81980 62.0 68.0 57.0 44.0 71.0 59.0 55.0 32.0 53.0 57.0 34.0 46.0 53.21981 - 50.0 69.0 62.0 - 81.0 62.0 82.0 49.0 48.0 53.0 67.0 62.31982 68.0 62.0 56.0 68.0 56.0 80.0 78.0 69.0 44.0 - 40.0 53.0 61.31983 68.0 62.0 56.0 68.0 56.0 80.0 78.0 69.0 44.0 - 40.0 53.0 61.31984 42.0 43.0 45.0 47.0 63.0 60.0 47.0 46.0 - 45.0 52.0 35.0 47.71985 70.0 50.0 43.0 41.0 62.0 52.0 51.0 53.0 31.0 41.0 34.0 60.0 49.01986 37.0 66.0 37.0 60.0 58.0 60.0 59.0 48.0 42.0 39.0 49.0 62.0 51.41987 46.0 70.0 54.0 29.0 67.0 65.0 73.0 63.0 40.0 47.0 48.0 58.0 55.01988 61.0 77.0 56.0 73.0 72.0 75.0 76.0 60.0 45.0 57.0 34.0 71.0 63.11989 64.0 59.0 - 80.0 73.0 - 58.0 - 68.0 49.0 59.0 67.0 64.11990 64.8 59.9 66.3 59.1 72.8 60.1 - 62.3 48.2 39.6 48.8 62.4 58.61991 57.9 67.6 65.4 62.5 60.7 78.3 75.1 63.3 27.9 25.0 34.0 36.1 54.51992 52.4 57.4 58.6 59.3 63.8 61.6 66.3 55.6 43.5 57.3 54.2 50.8 56.71993 61.6 72.3 46.2 64.6 46.7 68.6 59.7 66.4 55.1 46.7 42.6 51.7 56.91994 52.3 60.4 43.7 61.8 62.6 56.4 76.2 57.4 43.6 14.9 41.4 59.8 52.51995 53.1 - 53.4 55.0 56.3 71.4 65.1 - 43.6 52.5 - 55.5 56.21996 - 51.3 - - - 61.0 47.0 42.8 - - 38.9 33.9 45.81997 43.0 - 63.6 62.2 - 76.8 - 47.3 - - - 47.1 56.71998 52.8 55.7 53.8 60.2 54.8 51.4 61.7 52.0 38.4 36.0 32.4 23.9 47.71999 23.0 49.1 32.8 53.2 57.5 56.2 65.6 65.6 - - - - 50.42000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 43.8 - - - - - - - - - - - 43.8Min 23.0 34.0 26.0 29.0 36.0 29.0 26.0 22.0 19.0 10.0 9.0 23.9Max 70.0 77.0 69.0 80.0 74.0 81.0 78.0 82.0 68.0 57.3 59.0 71.0Ave 53.1 57.4 53.3 55.3 59.5 61.7 60.9 55.4 42.9 41.7 40.4 50.7 52.7




Table 4 Monthly Mean Wind Velocity

Station Name: Tabing-PadangElevation: 2.0m Unit: m/sec

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average1971 1.5 2.1 1.5 1.5 1.5 2.1 2.1 2.1 2.1 3.1 2.6 3.1 2.11972 2.1 2.1 2.1 2.6 2.1 2.6 2.6 2.6 2.6 2.1 2.6 3.6 2.41973 3.6 3.1 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.1 2.71974 1.5 2.6 2.6 2.1 2.1 2.1 2.6 2.1 2.6 2.6 2.6 1.5 2.21975 2.1 2.1 2.1 2.1 2.1 1.5 1.5 2.1 2.1 2.6 2.6 2.6 2.11976 3.1 6.2 6.7 3.1 1.5 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.91977 2.1 2.6 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.11978 2.1 2.1 2.1 1.5 2.1 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.41979 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 1.0 0.5 0.5 0.5 0.61980 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 2.1 0.5 0.5 0.5 0.61981 - 0.5 1.0 1.0 - 1.0 1.0 0.5 1.0 0.5 1.0 1.0 0.91982 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 - 1.0 1.0 1.01983 1.0 1.0 1.0 1.0 1.0 - 1.5 1.0 1.0 1.0 1.0 1.0 1.11984 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 - 1.0 1.0 1.0 1.01985 1.5 1.0 1.0 1.0 1.0 1.5 1.0 1.0 1.0 1.0 1.0 1.0 1.11986 1.0 1.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.5 1.0 1.5 1.21987 1.5 1.5 1.5 1.0 1.5 1.0 1.5 1.5 1.5 1.5 1.5 1.5 1.51988 1.5 1.5 1.0 1.5 1.5 1.0 1.5 1.0 1.5 1.5 1.5 1.5 1.41989 1.5 1.5 - 1.5 1.0 - 1.0 - 1.5 1.0 1.5 1.0 1.31990 0.1 0.2 0.1 0.1 0.1 0.2 - 0.1 0.2 0.2 0.2 0.2 0.21991 0.2 0.2 - 0.2 0.2 0.2 0.1 0.2 0.1 0.1 0.2 0.1 0.21992 0.3 0.2 0.1 0.1 0.1 0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.11993 0.1 0.2 0.1 0.1 0.1 0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.11994 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.2 0.1 0.1 0.11995 0.1 - 0.1 0.1 0.1 0.1 0.1 - 0.1 0.1 - 0.1 0.11996 - 0.2 - - - 0.1 0.1 0.1 - - 0.1 0.1 0.11997 0.1 - 0.2 0.2 - 0.1 - 0.2 0.2 - - 0.2 0.21998 0.2 0.2 - 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.21999 0.1 0.2 0.2 0.2 0.1 0.2 0.2 0.2 0.2 0.1 0.2 0.1 0.22000 0.2 0.2 0.2 0.5 0.5 0.5 0.6 0.6 0.6 0.6 0.6 0.5 0.52001 - - - - - - - - - - - - -2002 6.2 - - - - - - - - - - - 6.2Min 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1Max 6.2 6.2 6.7 3.1 2.6 2.6 2.6 2.6 2.6 3.1 2.6 3.6Ave 1.3 1.3 1.3 1.1 1.0 0.9 1.1 1.0 1.1 1.1 1.1 1.1 1.1




Table 5 Monthly Mean Pan Evaporation

Station Name: Lubuk Sukaping Unit: mm/day

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average1979 - 4.7 3.6 4.1 - - - - - - - - 4.11980 - - - - 4.2 4.7 4.3 4.5 2.9 3.0 2.6 3.1 3.71981 4.8 3.8 - - 2.5 4.1 3.7 4.0 3.1 2.6 4.1 4.6 3.71982 5.0 3.7 3.1 2.8 3.2 2.1 3.9 5.0 4.3 3.8 3.7 3.9 3.71983 4.6 4.7 4.9 4.3 4.1 4.5 4.4 4.1 4.2 4.3 3.8 4.1 4.31984 4.5 4.0 4.3 4.3 4.3 4.4 4.6 3.4 3.4 4.1 5.2 4.6 4.31985 5.3 5.4 5.6 4.2 4.0 4.5 3.8 4.4 3.5 - - - 4.5Min 4.5 3.7 3.1 2.8 2.5 2.1 3.7 3.4 2.9 2.6 2.6 3.1Max 5.3 5.4 5.6 4.3 4.3 4.7 4.6 5.0 4.3 4.3 5.2 4.6Ave 4.8 4.4 4.3 3.9 3.7 4.1 4.1 4.2 3.6 3.6 3.9 4.1 4.1

Source: Masang-3 HEPP Report, 1999

Station Name: Tanjung Pati Unit: mm/dayYear Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average1975 3.6 3.5 4.7 3.5 4.2 3.5 3.6 4.0 3.6 5.0 4.2 3.8 3.91976 3.6 3.7 5.5 4.5 4.1 4.5 4.2 5.7 3.4 4.0 3.0 3.4 4.11977 2.6 3.6 3.4 3.7 3.9 3.7 4.8 3.7 3.0 - 2.0 3.9 3.51978 3.7 3.9 3.7 4.3 4.0 4.7 5.0 4.6 5.5 5.0 - 2.3 4.21979 3.9 3.3 3.4 4.4 4.9 3.0 3.5 4.1 3.6 4.1 - 3.4 3.81980 - 4.3 2.4 2.8 3.2 - 3.0 - - 3.7 2.5 4.2 3.31981 3.4 5.7 2.7 - 3.4 2.6 3.2 4.7 - 4.8 3.8 - 3.81982 - 4.3 2.9 - 3.0 2.4 2.7 2.7 4.1 4.2 3.3 2.8 3.21983 2.2 2.9 3.5 3.5 3.0 3.7 2.8 3.2 3.1 3.1 2.9 3.1 3.11984 3.5 3.0 3.2 2.7 3.4 3.4 3.2 3.2 3.1 3.1 3.1 4.8 3.31985 3.0 6.6 3.5 2.8 2.9 - 3.1 2.6 2.6 - - - 3.4Min 2.2 2.9 2.4 2.7 2.9 2.4 2.7 2.6 2.6 3.1 2.0 2.3Max 3.9 6.6 5.5 4.5 4.9 4.7 5.0 5.7 5.5 5.0 4.2 4.8Ave 3.3 4.1 3.5 3.6 3.6 3.5 3.6 3.9 3.6 4.1 3.1 3.5 3.6




Table 6 Monthly Rainfall Records (1/13)

Station Name: ManinjauStation ID: 52B Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 144 176 89 267 177 142 67 126 82 122 262 173 1,8271970 156 90 128 143 110 101 39 150 420 363 314 103 2,1171971 56 287 234 200 104 75 73 231 240 72 59 77 1,7081972 37 148 250 84 73 145 29 54 160 46 7 172 1,2051973 133 71 - 418 314 64 105 265 275 184 74 183 -1974 79 229 105 294 220 260 112 237 493 261 248 101 2,6391975 132 259 56 328 188 144 203 - - - - - -1976 32 228 191 183 3 175 217 194 90 339 235 231 2,1181977 250 79 135 296 153 103 128 124 104 134 278 235 2,0191978 186 272 279 169 134 278 133 101 73 202 100 165 2,0921979 - - - - - - - - - - - - -1980 66 89 177 134 352 308 428 350 436 598 152 580 3,6701981 297 236 260 658 120 308 428 120 457 610 811 580 4,8851982 297 254 437 228 321 248 254 329 217 315 336 297 3,5331983 133 13 408 365 619 336 378 217 369 552 313 230 3,9331984 400 264 368 431 353 421 451 274 783 402 811 433 5,3911985 495 148 355 313 235 324 338 190 589 290 566 410 4,2531986 250 186 451 332 529 238 664 474 470 558 753 178 5,0831987 286 204 221 395 343 125 279 284 303 471 595 605 4,1111988 - - - - - - - - - 233 1,088 412 -1989 807 400 221 202 321 327 175 71 258 473 365 192 3,8121990 361 83 194 172 463 120 369 193 193 183 - - -1991 - 129 - 153 538 - - 231 319 - 876 577 -1992 42 134 154 564 129 17 200 353 294 365 380 170 2,8021993 291 156 260 253 428 168 331 156 324 264 - 362 -1994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 32 13 56 84 3 17 29 54 73 46 7 77Max 807 400 451 658 619 421 664 474 783 610 1,088 605Ave 224 180 237 286 271 201 246 215 316 320 411 294 3,199

Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG




Station Name: Limau PurutStation ID: 52C Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 - - - - - - - - - - - - -1970 - - - - - - - - - - - - -1971 - - - - - - - - - - - - -1972 - - - - - - - - - - - - -1973 - - - 503 309 271 71 452 393 400 332 371 -1974 157 218 200 578 469 259 196 237 590 314 410 410 4,0381975 411 320 312 416 226 44 359 250 487 408 - 329 -1976 182 330 246 309 97 249 265 215 273 869 691 288 4,0141977 362 379 283 292 222 134 92 - 218 304 469 203 -1978 - - - - - - - - - - - - -1979 - - - - - - - - - - - - -1980 244 111 216 331 210 226 410 411 243 551 - 426 -1981 - - - - - - - - - - - - -1982 - - - - 150 - - 289 413 296 418 - -1983 229 101 487 449 348 184 178 73 220 252 227 229 2,9771984 - 109 - - - - - - - - - - -1985 - - 183 - 127 185 115 171 272 210 365 219 -1986 97 114 197 181 278 114 337 282 263 218 330 489 2,9001987 462 223 365 377 164 198 182 510 517 303 480 318 4,0991988 - - - - - - - - - - - 229 -1989 300 334 207 1 335 65 276 247 396 273 511 381 3,3261990 452 257 308 288 - 344 432 77 514 - 318 338 -1991 457 146 561 379 178 58 126 185 227 71 392 491 3,2711992 100 238 316 152 387 59 - 367 202 251 224 220 -1993 221 227 361 320 - - 274 105 263 677 427 477 -1994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 97 101 183 1 97 44 71 73 202 71 224 203Max 462 379 561 578 469 344 432 510 590 869 691 491Ave 283 222 303 327 250 171 237 258 343 360 400 339 3,491





Station Name: Padang PanjangStation ID: 53 Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 371 392 431 459 339 301 415 417 206 204 582 465 4,5821970 186 111 338 381 181 194 137 62 295 413 557 258 3,1131971 243 168 448 220 195 176 229 209 416 384 400 518 3,6061972 346 355 559 573 216 248 185 64 268 109 290 551 3,7641973 247 252 302 947 763 247 411 1,088 943 720 786 950 7,6561974 277 581 873 1,030 899 401 342 105 413 138 500 581 6,1401975 224 236 134 339 169 86 203 308 321 262 287 354 2,9231976 161 112 393 329 112 260 324 217 421 490 709 193 3,7211977 - - - - - - - - - - - - -1978 258 421 289 343 232 328 101 - - 572 451 348 -1979 162 208 170 356 245 312 218 165 141 498 423 216 3,1141980 258 138 175 171 156 160 250 336 203 315 384 285 2,8311981 - - - - - - - - - - - - -1982 - - - 553 464 - - 232 187 - 334 - -1983 590 62 60 292 346 192 229 413 194 233 290 239 3,1401984 308 357 384 - - 251 215 - - - - - -1985 - - - - 362 213 282 126 319 257 422 411 -1986 327 138 447 457 400 82 217 172 604 625 366 508 4,3431987 268 329 254 434 545 189 273 181 148 245 291 410 3,5671988 279 184 317 312 181 209 162 - 408 411 621 314 -1989 418 456 459 153 275 209 85 206 352 439 333 245 3,6301990 525 157 392 86 158 385 168 299 269 449 280 197 3,3651991 277 260 274 361 220 83 43 179 182 135 634 469 3,1171992 56 50 143 143 227 74 160 172 161 262 282 360 2,0901993 - 173 158 138 45 66 212 31 224 245 215 214 -1994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - 402 - -1999 398 315 566 321 232 - - 253 315 617 521 497 -2000 - - - - - - - - - - - - -2001 - - 444 - - - - - - - - - -2002 - - - - - - - 180 361 - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 56 50 60 86 45 66 43 31 141 109 215 193Max 590 581 873 1,030 899 401 415 1,088 943 720 786 950Ave 294 248 348 382 303 212 221 246 320 365 432 390 3,760





Station Name: Bukit TinggiStation ID: 54 Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 - - - - - - - - - - - - -1970 - - - - - - - - - - - - -1971 - - - - - - - - - - - - -1972 - 154 196 209 194 107 27 - - - - - -1973 - 84 124 238 174 111 85 258 156 251 60 130 -1974 - - - - - - - - - - - - -1975 - - - - - - - - - - - - -1976 - - - - - - - - - - - - -1977 - - - - - - - - - - - - -1978 - - - 316 - - - - - - - - -1979 - - - - - - - - - - - - -1980 - - - - - - - - - - - - -1981 - - - - - - - - - - - 146 -1982 - - - - - - - 93 - - - - -1983 - - 196 - - - - - - - - - -1984 - - - - - - - - - - - - -1985 179 153 218 - 201 28 48 62 328 187 234 98 -1986 231 58 415 242 136 120 90 68 172 223 167 106 2,0281987 107 70 272 222 132 37 86 121 95 274 151 225 1,7921988 - - - - - - - - - - - 196 -1989 333 - 139 75 119 24 105 77 253 224 186 - -1990 - 463 - - - - - - - - - - -1991 - - - - - - - - - - - - -1992 - - 233 169 - - - 56 - - 290 154 -1993 135 102 252 273 269 85 162 72 251 231 256 191 2,2791994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 107 58 124 75 119 24 27 56 95 187 60 98Max 333 463 415 316 269 120 162 258 328 274 290 225Ave 197 155 227 218 175 73 86 101 209 232 192 156 2,021





Station Name: BasoStation ID: 54A Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 199 159 406 488 287 141 138 230 137 197 454 384 3,2201970 204 126 193 169 42 80 99 21 235 294 275 131 1,8691971 132 114 192 360 48 92 90 230 262 30 67 209 1,8261972 154 122 286 383 287 70 52 48 137 - - 157 -1973 609 100 69 179 279 62 38 151 61 665 - 169 -1974 73 220 13 257 168 141 92 122 450 74 79 244 1,9331975 82 276 162 258 97 40 130 99 241 31 92 39 1,5471976 - - - - - - - - - - - - -1977 - - - - - - - - - - - - -1978 127 - - 189 - - - - - 182 295 249 -1979 285 452 - 190 - - - - 229 316 284 - -1980 89 166 355 172 - 175 - 165 - - - - -1981 - - - - - - - - - - - - -1982 - - - - - - - 55 70 - - - -1983 266 - 293 255 - - - - - - - - -1984 - - - - - - - - - - - - -1985 - - - - - - - - - - - - -1986 - - - - - - - - - - - - -1987 - - - - - - - - - - - - -1988 - - - - - - - - - 56 - 106 -1989 273 84 118 203 128 87 56 149 154 243 - 239 -1990 70 - 100 65 - 55 - - - 164 - - -1991 88 36 255 115 147 42 4 26 52 - 197 384 -1992 85 38 141 53 201 2 164 35 158 66 - - -1993 - - - - - - - - - - - - -1994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 70 36 13 53 42 2 4 21 52 30 67 39Max 609 452 406 488 287 175 164 230 450 665 454 384Ave 182 158 199 222 168 82 86 111 182 193 218 210 2,012





Station Name: Padang MangatasStation ID: 54C Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 253 206 336 357 299 60 47 166 54 206 454 440 2,8781970 177 181 269 195 107 46 55 35 86 149 255 168 1,7231971 218 168 232 236 103 130 129 321 145 39 164 222 2,1071972 147 86 252 369 217 158 40 129 148 102 179 288 2,1151973 161 141 144 211 154 102 68 153 117 173 19 56 1,4991974 30 188 72 233 111 121 246 152 345 77 126 98 1,7991975 60 353 65 196 45 44 244 145 322 26 - - -1976 143 71 257 173 107 106 140 115 148 289 328 348 2,2251977 322 196 158 397 - - - - - - - - -1978 - - - 313 153 61 179 76 46 340 229 462 -1979 117 38 220 37 50 284 - 63 24 176 525 134 -1980 - - - - - - - - - - - - -1981 - - - - - - - - - - - - -1982 - - - - - - - - - - - - -1983 241 - - - - - - - - - - - -1984 - - - - - - - - - - - - -1985 - - - - - - - - - - - - -1986 - - - - - - - - - - - - -1987 - - - - - - - - - - - - -1988 - - - - - - - - - 109 81 259 -1989 - 237 - - - 10 - - 131 - - - -1990 - - - - - 46 - - - - 170 450 -1991 - 126 - - - - - - - - - - -1992 - - - - - - - 24 - 37 219 398 -1993 196 120 116 164 257 70 93 43 227 - 256 186 -1994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 30 38 65 37 45 10 40 24 24 26 19 56Max 322 353 336 397 299 284 246 321 345 340 525 462Ave 172 162 193 240 146 95 124 119 149 144 231 270 2,045





Station Name: PayakumbuhStation ID: 56 Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 159 140 387 133 222 30 3 81 84 89 304 444 2,0761970 313 75 241 197 84 71 136 96 203 223 189 127 1,9551971 172 195 101 190 50 140 124 357 200 12 119 239 1,8991972 196 96 - 495 478 209 148 76 - 83 173 - -1973 154 101 - 345 275 128 - 298 182 - - - -1974 48 182 89 443 199 129 121 150 - 38 96 121 -1975 75 288 177 264 79 90 240 127 324 20 64 47 1,7951976 82 47 230 169 69 155 146 201 180 204 - 319 -1977 359 221 257 287 206 168 133 92 82 202 422 445 2,8741978 302 178 483 321 239 82 117 33 93 320 254 469 2,8911979 217 234 126 134 95 164 106 104 112 153 388 111 1,9441980 189 109 189 198 210 172 87 165 186 165 352 121 2,1431981 189 - - - 210 175 87 165 - - - - -1982 - - - - - - - - - - - - -1983 167 84 - - - 34 126 65 149 303 47 - -1984 186 169 - - - - - - - - - - -1985 - - - 36 184 8 29 61 143 281 203 86 -1986 47 74 638 143 227 43 43 31 204 256 180 180 2,0661987 111 64 147 150 195 63 110 98 85 - - - -1988 - - - - - - - - - 45 539 94 -1989 - 291 - - - - - - - 424 - - -1990 - - - 584 231 36 475 3 764 1,313 212 258 -1991 90 116 406 374 109 57 41 121 23 115 147 299 1,8981992 142 30 89 109 31 - 77 6 68 35 482 70 -1993 10 50 11 168 356 64 74 10 174 367 350 143 1,7771994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 10 30 11 36 31 8 3 3 23 12 47 47Max 359 291 638 584 478 209 475 357 764 1,313 539 469Ave 160 137 238 249 187 101 121 111 181 232 251 210 2,181





Station Name: Koto TinggiStation ID: 56A Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 - - - - - - - - - - - - -1970 - - - - - - 99 - - - 275 - -1971 209 158 161 181 152 141 194 177 140 115 157 206 1,9911972 174 156 216 203 156 151 90 0 205 150 222 184 1,9071973 148 219 239 240 186 135 132 183 191 344 154 241 2,4121974 129 193 191 287 239 191 185 197 355 193 276 286 2,7221975 167 227 178 243 140 156 239 157 258 140 178 155 2,2381976 171 160 185 489 194 243 257 275 237 314 305 203 3,0331977 225 192 217 442 195 218 174 233 228 317 347 214 3,0021978 191 184 207 312 190 58 149 133 164 371 281 320 2,5601979 87 125 140 128 71 134 134 132 22 156 310 165 1,6041980 3 236 330 510 93 76 8 83 41 13 366 464 2,2231981 137 239 225 319 413 69 108 45 207 141 246 366 2,5151982 274 254 361 671 205 92 12 87 114 311 396 366 3,1431983 184 90 214 201 108 114 133 120 227 224 294 303 2,2121984 179 215 197 252 269 242 296 161 286 259 656 546 3,5581985 189 186 300 185 262 175 97 126 281 320 315 182 2,6181986 392 138 198 218 235 334 180 160 227 400 197 142 2,8211987 227 80 297 425 349 65 170 310 71 410 205 272 2,8811988 234 - - - - - - 194 289 210 380 129 -1989 437 205 104 81 138 60 76 155 201 283 277 317 2,3341990 163 202 185 227 314 192 182 173 220 351 307 230 2,7461991 339 95 447 240 266 67 95 68 71 241 265 845 3,0391992 214 483 735 175 320 29 284 95 150 208 296 332 3,3211993 172 132 397 231 285 91 256 122 160 706 380 247 3,1791994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 3 80 104 81 71 29 8 0 22 13 154 129Max 437 483 735 671 413 334 296 310 355 706 656 845Ave 202 190 260 285 217 138 154 147 189 269 295 292 2,638





Station Name: SulikiStation ID: 56B Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 - - - - - - - - - - - - -1970 - - - - - - - - - - - - -1971 148 109 111 127 104 96 136 124 95 76 108 146 1,3801972 122 103 153 143 199 104 57 54 146 103 158 129 1,4711973 30 14 83 244 85 12 41 145 131 159 109 119 1,1721974 60 152 79 182 149 236 279 207 503 116 156 161 2,2801975 61 152 79 185 16 43 189 45 210 17 78 42 1,1171976 67 32 139 148 14 140 147 156 9 11 22 21 9061977 151 106 128 187 130 9 60 120 121 215 383 112 1,7221978 246 94 310 324 170 115 7 124 6 257 199 267 2,1191979 149 102 217 128 51 207 181 236 165 160 503 383 2,4821980 82 80 128 151 145 126 76 83 129 167 379 186 1,7321981 192 96 123 102 237 126 76 9 67 196 73 29 1,3261982 47 89 194 354 177 114 119 86 271 176 253 102 1,9821983 153 33 51 66 166 102 67 71 127 232 107 80 1,2551984 172 194 277 186 184 146 156 18 149 70 353 282 2,1871985 204 127 191 107 226 19 76 133 258 124 349 149 1,9631986 283 98 418 223 194 72 41 29 130 197 181 229 2,0951987 97 89 389 213 501 25 34 154 218 496 218 128 2,5621988 488 294 451 388 115 89 142 412 351 62 558 88 3,4381989 766 112 221 181 136 85 81 194 396 560 417 186 3,3351990 823 321 228 188 424 18 200 0 227 689 416 516 4,0501991 608 192 1,486 1,092 365 202 65 92 297 364 722 1,441 6,9261992 164 372 347 100 281 17 261 93 401 149 429 626 3,2401993 515 321 162 376 598 140 109 19 790 1,545 853 489 5,9171994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - 0 254 0 87 0 - - - - - -Min 30 14 0 66 0 9 0 0 6 11 22 21Max 823 372 1,486 1,092 598 236 279 412 790 1,545 853 1,441Ave 245 143 249 235 194 97 108 113 226 267 305 257 2,440





Station Name: Kota BaharuStation ID: 57 Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 - - - - - - - - - - - - -1970 - - - - - - - - - - - - -1971 - - - - - - - - - - - - -1972 - - - 362 382 146 44 61 - 319 346 - -1973 183 261 349 379 348 219 - 205 239 - - - -1974 61 276 154 217 135 127 99 74 143 153 93 253 1,7851975 196 121 272 142 180 85 268 193 208 151 323 160 2,2991976 123 114 89 89 64 123 58 211 151 372 - - -1977 - - 202 234 22 42 14 31 148 63 207 216 -1978 96 90 - 354 204 208 - 91 29 - 390 812 -1979 275 459 278 372 182 130 106 129 36 288 503 374 3,1321980 374 380 313 328 - 117 149 83 315 93 - 142 -1981 90 570 478 64 226 38 211 30 270 533 108 362 2,9801982 - - 239 - 362 - - - - - - - -1983 392 173 - 122 290 122 135 - - - - - -1984 - - - - - - - - - - - - -1985 - - - 75 206 2 94 57 366 254 226 289 -1986 399 100 409 324 147 89 165 47 - 377 413 507 -1987 204 234 321 175 433 - - - - - - - -1988 - - - - - - - - - 179 146 - -1989 466 159 405 247 238 47 57 186 416 446 402 382 3,4511990 - 468 - - 185 101 115 6 104 622 331 501 -1991 463 - 408 623 210 36 23 130 219 146 420 874 -1992 386 241 365 372 263 59 194 85 307 97 - - -1993 - - - - - - - - - - - - -1994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 61 90 89 64 22 2 14 6 29 63 93 142Max 466 570 478 623 433 219 268 211 416 622 503 874Ave 265 260 306 263 227 99 115 101 211 273 301 406 2,828





Station Name: BonjolStation ID: 58C Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 - - - - - - - - - - - - -1970 - - - - - - - - - - - - -1971 - - - - - - - - - - - - -1972 - - - - - - - - - - - - -1973 - - - - - - 120 393 374 416 303 341 -1974 177 160 368 516 227 185 160 156 508 115 289 292 3,1531975 159 175 150 374 74 140 286 80 131 251 90 223 2,1331976 - - - - - - - - - - - - -1977 - - - - - - - - - - - - -1978 - - - - - - - - - - - - -1979 - - - - - - - - - - - - -1980 - - - - - - - - - - - - -1981 - - - - - - - - - - - - -1982 - - - - - - - 291 347 - 477 - -1983 224 143 546 925 560 357 - 420 492 - 766 - -1984 - 453 451 - - 276 408 349 658 499 1,126 - -1985 569 330 604 444 835 139 340 358 510 587 585 316 5,6171986 423 165 496 487 523 359 512 453 494 664 348 119 5,0431987 162 149 499 840 1,091 - - - - - - - -1988 - - - - - - - - - 421 996 527 -1989 262 370 277 243 424 131 267 416 637 681 742 181 4,6311990 - - - 407 320 - - - - 705 - 516 -1991 391 211 622 548 274 189 119 230 433 437 794 655 4,9031992 - 178 271 528 408 157 301 325 384 385 372 292 -1993 272 267 481 419 - 200 399 237 312 563 482 481 -1994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 159 143 150 243 74 131 119 80 131 115 90 119Max 569 453 622 925 1,091 359 512 453 658 705 1,126 655Ave 293 236 433 521 474 213 291 309 440 477 567 358 4,613





Station Name: JambakStation ID: 58F Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 - - - - - - - - - - - - -1970 - - - - - - - - - - - - -1971 - - - - - - - - - - - - -1972 - - - - - - - - - - - - -1973 - - - - - - 144 360 284 430 162 218 -1974 39 205 200 445 323 198 183 214 620 205 416 444 3,4921975 117 288 344 493 287 117 478 236 495 237 259 293 3,6441976 - - - - - - - - - - - - -1977 285 202 265 844 211 268 155 307 295 523 600 252 4,2071978 274 239 547 625 687 199 335 246 219 550 756 354 5,0311979 204 264 339 305 136 354 551 312 282 372 716 247 4,0821980 177 219 589 587 555 262 300 256 292 469 391 501 4,5981981 244 225 182 784 560 262 300 106 618 550 231 268 4,3301982 113 301 493 401 307 144 199 149 273 276 409 220 3,2851983 115 125 250 730 413 461 158 313 338 298 335 244 3,7801984 268 213 220 751 222 190 383 159 415 296 786 289 4,1921985 269 245 500 172 497 80 186 290 524 464 549 373 4,1491986 411 119 433 241 359 271 226 153 300 431 585 248 3,7771987 194 118 490 623 350 84 245 402 397 630 308 311 4,1521988 298 149 368 304 185 188 115 479 334 20 191 499 3,1301989 221 269 191 221 213 33 136 140 393 195 344 86 2,4421990 266 167 272 169 239 116 312 95 309 415 399 318 3,0771991 252 200 482 464 320 151 138 95 470 470 713 570 4,3251992 80 192 203 372 364 169 239 233 261 333 249 341 3,0361993 226 147 424 304 438 204 207 197 333 456 442 445 3,8231994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 39 118 182 169 136 33 115 95 219 20 162 86Max 411 301 589 844 687 461 551 479 620 630 786 570Ave 213 205 357 465 351 197 250 237 373 381 442 326 3,797





Station Name: Lubuk SikapingStation ID: 59 Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1969 - - - - - - - - - - - - -1970 - - - - - - - - - - - - -1971 314 288 289 300 285 279 306 298 279 266 287 313 3,5041972 297 284 318 311 338 285 253 251 313 284 320 301 3,5551973 255 246 284 374 286 245 306 298 279 266 287 313 3,4391974 297 284 318 311 338 285 253 251 313 284 320 301 3,5551975 255 246 284 374 286 245 144 359 283 430 165 218 3,2891976 146 119 182 375 207 332 369 414 316 516 491 230 3,6971977 285 202 301 844 211 268 155 307 295 523 600 252 4,2431978 274 239 547 625 687 199 335 246 219 550 156 354 4,4311979 204 264 279 300 136 354 551 312 282 372 216 247 3,5171980 177 219 589 587 555 262 300 256 272 473 408 328 4,4261981 244 225 182 784 560 262 300 78 618 550 231 268 4,3021982 71 263 556 365 412 192 219 43 228 216 409 127 3,1011983 115 92 250 730 388 461 144 313 338 298 335 166 3,6301984 268 177 187 340 261 190 383 148 415 296 786 246 3,6971985 273 286 460 344 477 80 186 177 638 388 544 373 4,2261986 411 240 175 335 357 298 280 146 284 427 - - -1987 194 111 490 559 330 - - - - - - - -1988 - - - - - - - - - - - 160 -1989 - - - - - - - - - - - - -1990 - - - - - - - - - - - - -1991 - - - - - - - - - - - - -1992 - - - - - - - - - - - - -1993 - - - - - - - - - - - - -1994 - - - - - - - - - - - - -1995 - - - - - - - - - - - - -1996 - - - - - - - - - - - - -1997 - - - - - - - - - - - - -1998 - - - - - - - - - - - - -1999 - - - - - - - - - - - - -2000 - - - - - - - - - - - - -2001 - - - - - - - - - - - - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 - - - - - - - - - - - - -2006 - - - - - - - - - - - - -2007 - - - - - - - - - - - - -Min 71 92 175 300 136 80 144 43 219 216 156 127Max 411 288 589 844 687 461 551 414 638 550 786 373Ave 240 223 335 462 360 265 280 244 336 384 370 262 3,760




Table 19 Selected Hourly Rainfall Records

Unit:mm

1 2 3 4 5 6 7 8 9 10 11 12Gunung 1982/12/12 55.2 10.2 8.5 2.6 1.8 16.1 4.5 0.2 0.6 3.7 4.7 2.3Melintang 1983/1/12 59.9 40.9 0.2 1.0 17.8

1983/3/22 59.4 13.3 30.3 7.0 1.3 2.2 3.5 1.81983/4/30 55.4 14.5 33.3 5.3 0.7 0.1 1.51983/9/6 54.6 20.2 28.0 5.3 0.8 0.31983/12/8 54.6 18.3 19.3 4.0 5.3 4.8 2.91984/3/16 79.7 67.0 8.5 4.21984/4/13 95.6 0.3 5.4 66.0 11.7 1.8 2.1 3.2 2.1 1.7 1.1 0.21984/4/23 76.8 4.2 70.0 2.61984/10/17 52.8 49.0 2.3 1.51984/11/3 78.1 42.3 30.0 4.3 1.51984/11/9 118.0 18.0 50.0 45.0 3.7 1.31984/11/18 55.3 4.2 37.0 4.0 2.5 3.3 1.0 2.3 1.01985/1/3 65.9 25.0 25.0 15.0 0.91985/1/6 51.3 44.5 2.5 1.2 2.1 0.8 0.21985/1/25 64.5 28.1 35.1 0.6 0.71985/2/11 95.1 3.0 40.3 20.5 1.2 23.1 6.0 0.8 0.21985/3/11 99.5 6.6 0.5 15.0 27.4 35.0 14.2 0.81985/3/31 52.9 24.6 20.7 5.6 2.01985/5/6 62.0 30.0 13.3 1.1 10.5 5.4 1.71985/5/14 132.6 5.2 50.5 7.2 2.2 13.3 31.0 18.0 4.0 0.7 0.4 0.11985/9/11 60.5 55.0 3.9 0.9 0.71985/10/8 55.8 50.9 0.1 1.2 1.4 1.1 0.4 0.71986/3/9 76.2 4.5 32.4 3.1 1.8 3.7 1.3 6.2 0.3 0.1 0.9 1.3 20.6

Maninjau 1986/5/29 103.6 9.2 10.0 10.0 20.0 40.0 14.41986/7/8 116.8 2.6 43.0 60.0 11.21986/7/13 58.0 11.0 20.0 20.0 6.9 0.11986/8/3 55.6 1.0 1.8 0.8 34.0 4.0 14.01986/10/10 71.3 2.8 0.3 0.1 0.1 3.2 6.0 20.0 17.0 3.0 16.0 1.8 1.01987/8/1 83.0 83.01987/10/7 54.5 53.5 1.0

Sungai Talang 1991/9/29 70.5 68.0 2.0 0.5Barat 1991/12/28 68.0 4.0 2.0 2.0 2.0 20.0 12.0 8.0 3.0 3.0 4.0 4.0 4.0

1992/3/8 66.2 1.0 1.5 30.0 4.2 8.0 2.0 4.5 2.0 5.0 8.0Solok Bio-Bio 1991/10/18 63.7 3.0 3.2 10.2 0.0 0.0 10.2 12.0 25.1

1992/3/7 54.8 45.2 0.8 2.0 1.2 5.6Muara Paiti 1984/10/17 63.3 31.5 31.3 0.3 0.2

1984/11/3 87.5 5.3 5.3 0.2 32.7 41.1 1.5 1.41984/11/5 74.2 37.7 12.5 14.4 0.2 0.1 1.1 6.0 2.21984/11/18 59.3 14.0 32.9 2.6 3.2 1.5 4.5 0.4 0.21984/12/1 67.1 14.7 43.3 4.5 2.7 1.91985/2/10 99.9 42.2 50.0 4.0 3.6 0.11985/3/9 77.5 60.0 8.2 8.9 0.3 0.11985/8/16 67.3 1.8 60.0 3.0 1.8 0.5 0.21985/10/6 55.8 40.9 5.5 0.8 1.6 2.1 3.4 1.3 0.21986/12/7 54.3 16.8 30.0 5.2 2.0 0.31987/1/29 92.6 30.0 40.0 15.0 6.0 1.61987/2/8 65.5 7.4 40.0 15.0 3.11988/9/5 50.8 47.8 1.2 0.7 0.8 0.31988/9/11 82.5 22.5 45.0 5.0 7.7 2.31989/1/10 55.9 44.6 11.31989/1/16 61.4 0.9 20.6 0.6 0.2 14.2 20.0 3.0 1.0 0.91989/1/18 70.9 3.4 5.5 1.3 0.1 33.1 27.4 0.11989/6/25 52.4 17.5 19.0 12.0 1.7 1.5 0.71989/11/7 58.7 30.1 10.8 2.6 1.2 3.3 0.7 2.1 3.2 0.5 3.6 0.3 0.31989/11/13 51.6 33.2 9.2 6.7 2.5

Patir 1989/4/3 154.0 3.0 3.0 1.0 127.0 13.0 7.0Puar Datar 1992/12/9 82.0 34.0 18.0 7.0 16.0 6.0 1.0Halaban Dua 1991/8/30 82.2 49.3 28.1 4.8

1991/11/19 60.0 10.0 30.0 2.0 4.0 14.01991/12/14 76.8 3.8 34.0 15.2 2.0 8.1 11.3 0.9 1.51991/12/28 81.8 22.1 4.0 7.1 19.2 8.1 11.2 6.0 4.0 0.11992/4/23 80.3 6.0 28.0 1.2 32.0 4.0 5.1 4.0

Source:Masang-3 HEPP, 1999.

Station Name DateTotal

RainfallHour



Table 20 Monthly Mean Runoff Records

Station Name: SipisangStation ID: 01-164-00-01 Unit: m3/s

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1975 - - - - - - - - 2.9 13.4 17.2 15.4 -1976 14.8 12.1 15.2 18.1 15.9 16.8 15.5 13.6 12.9 21.1 29.0 62.8 20.71977 - - 18.8 20.4 20.0 16.4 14.2 12.8 12.3 16.8 - - -1978 20.9 18.4 - 18.9 13.7 - - 10.9 14.0 16.4 25.6 21.6 -1979 - - - - - - - 16.3 - 17.4 - - -1980 16.4 15.4 19.6 21.0 15.8 19.3 16.4 - - - - - -1981 - - - - 24.4 16.5 13.6 12.2 16.3 26.4 21.6 20.5 -1982 16.0 18.0 20.5 27.2 29.4 18.2 14.7 13.9 12.9 14.3 18.2 23.3 18.91983 17.7 12.6 15.7 22.6 26.5 18.0 15.7 16.3 21.4 19.2 18.9 18.3 18.61984 16.5 13.7 14.6 25.0 17.3 16.4 14.5 12.7 16.9 21.0 40.4 28.6 19.81985 25.3 21.6 25.1 23.3 24.3 22.9 17.6 14.5 20.0 18.9 25.9 22.6 21.81986 22.6 17.3 25.4 23.7 35.8 24.8 19.3 19.0 17.8 21.5 18.5 16.3 21.81987 13.1 10.2 14.9 18.1 25.1 - 10.3 24.1 - - - - -1988 - - - - - - - - - - - - -1989 - - - - - - - - - - - - -1990 - - - - - - - - - 19.9 22.5 - -1991 17.6 19.4 24.7 25.5 19.9 14.7 12.6 11.8 12.3 14.8 27.2 39.2 20.01992 - - - 17.0 - - - - - - - - -1993 31.0 36.0 39.1 40.1 43.7 42.5 26.5 30.3 25.2 21.2 22.5 21.8 31.71994 21.8 19.0 21.0 21.3 22.1 16.2 17.6 17.8 15.2 12.1 22.9 32.0 19.91995 22.3 24.4 21.9 25.4 26.1 21.5 17.3 19.6 18.6 25.2 21.8 23.4 22.31996 27.0 28.7 29.4 29.5 20.2 23.8 17.3 18.7 18.1 23.2 26.0 27.9 24.21997 17.6 12.4 13.8 15.9 16.5 9.7 8.4 7.7 7.9 8.7 10.4 12.1 11.81998 12.6 11.2 9.9 13.6 11.6 8.2 7.5 17.9 25.2 21.1 22.8 37.1 16.61999 33.7 22.2 23.6 18.2 16.8 11.4 14.9 16.1 27.2 34.3 45.5 49.3 26.12000 34.2 18.6 18.2 20.4 15.8 14.1 16.1 15.1 13.9 18.5 59.0 38.3 23.52001 - 3.7 - - 12.1 12.3 7.4 - - 6.6 2.2 - -2002 - - - - - - - - - - - - -2003 - - - - - - - - - - - - -2004 - - - - - - - - - - - - -2005 20.5 19.9 20.7 34.2 21.9 16.4 17.9 18.2 38.4 41.6 46.8 36.0 27.72006 39.5 37.8 33.7 32.5 26.2 20.0 22.0 14.9 26.7 27.7 38.9 42.2 30.22007 24.6 32.2 22.3 22.2 23.0 17.5 26.9 25.9 36.3 26.9 30.7 25.0 26.12008 21.1 33.0 25.9 30.3 24.5 29.4 38.7 47.6 38.2 40.1 36.2 31.0 33.0Min 12.6 3.7 9.9 13.6 11.6 8.2 7.4 7.7 2.9 6.6 2.2 12.1Max 39.5 37.8 39.1 40.1 43.7 42.5 38.7 47.6 38.4 41.6 59.0 62.8Ave 22.1 19.9 21.5 23.5 21.9 18.6 16.8 17.8 19.6 21.1 27.1 29.3 21.6

Source: Pusair. Masang-3 HEPP, 1999.



Table 21 Regression Analysis of Monthly Rainfall Records

Number of Data

52B 52C 53 54 54A 54C 56 56A 56B 57 58C 58F 59Maninjau 52B 241 161 196 83 102 102 179 241 241 154 120 200 178Limau Purut 52C 161 173 159 71 78 69 140 173 173 127 115 158 109Padang Panjang 53 196 159 230 80 118 113 183 224 230 153 123 188 152Bukit Tinggi 54 83 71 80 85 32 35 60 85 85 51 63 74 48Baso 54A 102 78 118 32 118 75 94 118 118 89 69 90 80Padang Mangatas 54C 102 69 113 35 75 120 108 120 120 78 51 78 96Payakumbuh 56 179 140 183 60 94 108 204 204 204 154 100 167 150Koto Tinggi 56A 241 173 224 85 118 120 204 270 270 179 132 228 196Suliki 56B 241 173 230 85 118 120 204 270 276 179 132 234 196Kota Baharu 57 154 127 153 51 89 78 154 179 179 179 93 156 133Bonjol 58C 120 115 123 63 69 51 100 132 132 93 132 132 78Jambak 58F 200 158 188 74 90 78 167 228 234 156 132 234 154Lubuk Sikaping 59 178 109 152 48 80 96 150 196 196 133 78 154 196

Correlation Ratio52B 52C 53 54 54A 54C 56 56A 56B 57 58C 58F 59

Maninjau 52B 1.000 0.269 0.162 0.275 0.194 0.146 0.123 0.248 0.274 0.144 0.572 0.331 0.286Limau Purut 52C 0.269 1.000 0.341 0.236 0.441 0.348 0.364 0.339 0.322 0.262 0.260 0.413 0.277Padang Panjang 53 0.162 0.341 1.000 0.185 0.240 0.131 0.274 0.198 0.081 0.247 0.254 0.187 0.128Bukit Tinggi 54 0.275 0.236 0.185 1.000 0.548 0.655 0.651 0.529 0.503 0.668 0.445 0.565 0.582Baso 54A 0.194 0.441 0.240 0.548 1.000 0.428 0.370 0.345 0.208 0.406 0.364 0.489 0.129Padang Mangatas 54C 0.146 0.348 0.131 0.655 0.428 1.000 0.632 0.511 0.423 0.533 0.203 0.596 0.260Payakumbuh 56 0.123 0.364 0.274 0.651 0.370 0.632 1.000 0.287 0.384 0.419 0.393 0.307 0.244Koto Tinggi 56A 0.248 0.339 0.198 0.529 0.345 0.511 0.287 1.000 0.516 0.401 0.467 0.439 0.445Suliki 56B 0.274 0.322 0.081 0.503 0.208 0.423 0.384 0.516 1.000 0.553 0.361 0.317 0.327Kota Baharu 57 0.144 0.262 0.247 0.668 0.406 0.533 0.419 0.401 0.553 1.000 0.375 0.261 0.130Bonjol 58C 0.572 0.260 0.254 0.445 0.364 0.203 0.393 0.467 0.361 0.375 1.000 0.619 0.608Jambak 58F 0.331 0.413 0.187 0.565 0.489 0.596 0.307 0.439 0.317 0.261 0.619 1.000 0.780Lubuk Sikaping 59 0.286 0.277 0.128 0.582 0.129 0.260 0.244 0.445 0.327 0.130 0.608 0.780 1.000

Slope of Formula (Y=aX)

52B 52C 53 54 54A 54C 56 56A 56B 57 58C 58F 59Maninjau 52B 1.000 0.851 0.647 1.562 0.997 0.945 0.846 1.034 0.824 0.888 0.727 0.828 0.752Limau Purut 52C 0.834 1.000 0.731 1.405 1.506 1.509 1.193 1.087 0.691 0.976 0.633 0.818 0.816Padang Panjang 53 0.904 0.962 1.000 1.648 1.525 1.576 1.098 1.177 0.720 1.020 0.722 0.836 0.983Bukit Tinggi 54 0.452 0.516 0.375 1.000 0.733 0.929 0.745 0.659 0.454 0.589 0.364 0.521 0.505Baso 54A 0.539 0.464 0.374 1.004 1.000 0.894 0.562 0.668 0.388 0.529 0.385 0.476 0.558Padang Mangatas 54C 0.597 0.480 0.357 0.910 0.737 1.000 0.828 0.810 0.658 0.647 0.404 0.503 0.532Payakumbuh 56 0.544 0.549 0.498 1.033 1.007 0.959 1.000 0.734 0.534 0.695 0.416 0.517 0.511Koto Tinggi 56A 0.626 0.685 0.543 1.223 0.958 0.972 0.786 1.000 0.668 0.741 0.529 0.634 0.626Suliki 56B 0.585 0.723 0.542 1.383 1.000 0.921 0.911 0.925 1.000 0.823 0.610 0.654 0.421Kota Baharu 57 0.592 0.683 0.610 1.445 1.257 1.135 0.867 0.941 0.768 1.000 0.541 0.621 0.566Bonjol 58C 1.112 1.156 0.899 2.210 1.645 1.514 1.317 1.461 0.873 1.272 1.000 1.206 1.235Jambak 58F 0.860 0.975 0.789 1.602 1.514 1.547 1.126 1.212 0.821 1.031 0.703 1.000 1.020Lubuk Sikaping 59 0.934 0.941 0.695 1.696 1.147 1.360 1.347 1.292 1.663 1.117 0.682 0.900 1.000

X



Table 22 Estimated Monthly Basin Mean Rainfall at Sipisang AWLR Station

Unit: mm

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual1973 126 99 206 360 262 75 105 234 241 218 96 190 2,2131974 89 213 122 281 217 242 145 225 462 231 245 150 2,6221975 133 241 86 294 160 137 210 80 144 156 93 149 1,8821976 67 193 184 250 48 187 219 209 116 300 230 204 2,2071977 234 108 153 319 160 120 132 149 134 184 304 218 2,2151978 193 234 266 217 150 211 124 111 87 246 152 211 2,2021979 107 132 174 150 70 177 244 164 121 183 375 164 2,0611980 37 100 164 190 186 162 192 177 209 275 187 373 2,2521981 178 165 175 365 170 160 215 62 249 313 410 335 2,7971982 195 176 289 287 202 138 123 169 146 224 260 221 2,4301983 114 30 229 209 306 180 199 127 222 310 212 176 2,3141984 229 182 230 261 231 250 276 156 415 238 533 339 3,3391985 275 119 240 187 183 181 174 123 342 210 349 232 2,6151986 225 121 280 214 299 186 329 242 266 350 385 132 3,0291987 184 114 202 288 277 71 162 208 168 345 323 334 2,6751988 228 177 278 239 75 61 88 201 259 161 336 128 2,2311989 397 174 105 86 124 53 70 138 201 265 256 254 2,1211990 201 184 169 192 279 149 167 133 197 337 281 228 2,5161991 313 96 476 290 243 74 83 63 100 232 291 771 3,0301992 176 397 582 156 278 31 243 90 157 183 267 314 2,8741993 181 131 328 217 282 89 209 102 200 671 373 245 3,027Min 37 30 86 86 48 31 70 62 87 156 93 128Max 397 397 582 365 306 250 329 242 462 671 533 771Ave 185 161 235 240 200 140 177 151 211 268 284 255 2,507



Table 23 Annual Rainfall Loss of Various River Basins in Sumatra

No.

Sta

tion

Riv

er

Gau

ge ID

Cat

chm

ent

Bas

inA

nnua

l A

nnua

l A

nnua

lR

unof

fO

bser

vatio

nN

ame

Bas

inAr

eaM

ean

Mea

nR

unof

fR

ainf

all

Coe

ff.P

erio

dR

ainf

all

Run

off

Dep

thLo

ss(k

m2 )

(mm

)(m

3 /sec

)(m

m)

(mm

)

1Lh

ok N

ibon

gK

r. Ja

mbu

Aye

01-0

27-0

1-02

4,58

32,

685

175.

71,

209

1,47

60.

4519

72-1

993

2S

taba

tS

. Wam

pu01

-040

-01-

013,

870

3,09

920

6.8

1,68

51,

414

0.54

1974

-199

3

3Lb

. Sip

elan

duk

Bt.

Pan

e01

-055

-03-

0282

82,

250

28.4

1,08

21,

168

0.48

1973

-199

3

4Lb

. Ben

daha

raS

. Rok

an01

-058

-02-

013,

325

2,58

914

1.5

1,34

21,

247

0.52

1974

-199

3

5Tj

. Am

palu

Bt.

Kua

ntan

01-0

66-0

4-01

2,21

52,

211

77.6

1,10

51,

106

0.50

1975

-199

3

6S

unga

i Dar

ehB

t. H

ari

01-0

71-0

1-01

4,45

23,

239

310.

22,

197

1,04

20.

6819

75-1

993

7M

uara

Inum

Bt.

Har

i01

-071

-02-

011,

455

3,34

610

7.6

2,33

21,

014

0.70

1973

-198

7

8M

arta

pura

A. M

usi

01-0

74-0

1-01

4,26

02,

821

225.

01,

666

1,15

50.

5919

60-1

984

9B

anja

rmas

inW

. Tl.

Baw

ang

01-0

77-0

2-07

604

3,12

536

.81,

921

1,20

40.

6119

72-1

993

10K

unyi

rW

. Sek

ampu

ng01

-080

-01-

0443

82,

740

23.1

1,66

31,

077

0.61

1968

-199

3

11K

p. D

aran

gK

r. A

ceh

01-0

01-0

1-01

1,08

12,

012

33.1

966

1,04

60.

4819

77-1

993

12Tu

i Kar

eng

Kr.

Teun

om01

-205

-01-

012,

403

3,43

718

3.9

2,41

31,

024

0.70

1982

-199

3

13H

p. B

aru

Bt.

Toru

01-1

78-0

1-01

2,77

32,

843

128.

91,

466

1,37

70.

5219

72-1

993

14A

ir B

atu

Bt.

Indr

apur

a01

-141

-01-

0146

82,

887

31.3

2,10

977

80.

7319

73-1

993

15A

ir G

adan

gB

t. P

asam

an01

-165

-01-

011,

339

3,60

012

1.3

2,85

774

30.

7919

73-1

993

16D

espe

tah

A. M

usi

01-0

74-0

1-02

627

3,10

045

.22,

273

827

0.73

1974

-199

1

Sou

rce

: Sec

tora

l Rep

ort V

ol. 2

: H

ydro

logy

, Hyd

ro In

vent

ory

Stu

dy, J

uly

1997



Table 24 Area Reduction Factor for Masang River Basin

Maninjau Payakumbuh

1 1973/9/19 115 0 58 0.502 1974/5/3 90 6 48 0.533 1980/9/8 161 2 82 0.514 1984/1/9 91 45 68 0.755 1985/9/28 125 0 63 0.506 1986/11/26 148 0 74 0.507 1987/4/8 129 35 82 0.648 1988/11/23 175 44 110 0.639 1989/6/7 200 0 100 0.5010 1990/1/16 81 0 41 0.5011 1991/12/29 126 53 90 0.7112 1992/4/18 125 0 63 0.5013 1993/9/14 115 0 58 0.5014 1973/5/10 1 103 52 0.5015 1974/5/26 0 65 33 0.5016 1981/1/20 0 65 33 0.5017 1983/9/5 37 55 46 0.8418 1985/10/8 64 103 84 0.8119 1986/9/28 1 79 40 0.5120 1987/7/9 0 70 35 0.5021 1989/2/21 2 57 30 0.5222 1990/7/23 0 200 100 0.5023 1991/8/13 22 76 49 0.6424 1992/4/1 30 95 63 0.6625 1993/5/25 35 70 53 0.75

0.58

AverageArea

ReductionFactor

Point Rainfall (mm)

Average

Maninjau

Payakumbuh

No Date



Table 25 Annual Maximum 1-Day Rainfall at Payakumbuh Station

Unit: mm

Year Rainfall1951 961952 1001953 761954 681955 661956 671957 921958 -1959 851960 771961 841962 1301963 491964 801965 751966 2701967 2501968 951969 941970 751971 931972 -1973 1031974 651975 1101976 791977 1131978 1041979 821980 1501981 651982 -1983 551984 451985 1031986 791987 701988 591989 971990 2001991 761992 951993 70

Source: BMKG. Masang-3 HEPP, 1999.



Table 26 Calculation of Probable Maximum Precipitation (PMP)

Annual Maximun 1-Day Precipitation at Payakumbuh Station

Unit: mmYear Rainfall Max = 270 mm (1966)

1951 961952 100 n = 401953 76 Xn = 96.1 mm1954 68 Sn = 47.1 mm1955 66 Xn-m = 91.6 mm1956 67 Sn-m = 38.2 mm1957 921958 - Xn-m / Xn = 0.951959 85 Sn-m / Sn = 0.811960 771961 84 Adjustment for Maximum Observed Event1962 130 fX1 = 97%1963 49 fS1 = 89%1964 801965 75 Adjustment for Sample Size1966 270 fX2 = 100.5%1967 250 fS2 = 101.6%1968 951969 94 Statistical Coefficient1970 75 Km = 15.51971 931972 - Adjustment for Fixed Observational Time Intervals1973 103 f0 = 113%1974 651975 110 Computation of PMP1976 79 Xn = fX1 * fX2 * Xn

1977 113 = 93.6 mm1978 104 Sn = fS1 * fS2 * Sn

1979 82 = 42.6 mm1980 150 Xm = Xn + Km * Sn

1981 65 = 754.0 mm1982 - PMP = f0 * Xm

1983 55 = 852.0 mm1984 451985 1031986 791987 701988 591989 971990 2001991 761992 951993 70



Table 27 Ratios for SCS Unit Hydrograph

t/tp q/qp

0.0 0.0000.1 0.0300.2 0.1000.3 0.1900.4 0.3100.5 0.4700.6 0.6600.7 0.8200.8 0.9300.9 0.9901.0 1.0001.1 0.9901.2 0.9301.3 0.8601.4 0.7801.5 0.6801.6 0.5601.7 0.4601.8 0.3901.9 0.3302.0 0.2802.2 0.2072.4 0.1472.6 0.1072.8 0.0773.0 0.0553.2 0.0403.4 0.0293.6 0.0213.8 0.0154.0 0.0114.5 0.0055.0 0.000



Table 28 Average Rainfall Loss at Sipisang AWLR Station

Monthly Runoff Sipisang

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec1982 16 18 21 27 29 18 15 14 13 14 18 231983 18 13 16 23 26 18 16 16 21 19 19 181984 16 14 15 25 17 16 15 13 17 21 40 291985 25 22 25 23 24 23 18 14 20 19 26 231986 23 17 25 24 36 25 19 19 18 21 19 16

Adjusted Monthly Basin Mean RainfallYear Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec1982 195 176 289 287 202 138 123 169 146 224 260 2211983 114 30 229 209 306 180 199 127 222 310 212 1761984 181 143 182 206 182 197 218 123 328 188 420 2671985 275 119 240 187 183 181 174 123 342 210 349 2321986 225 121 280 214 299 186 329 242 266 350 385 132

Number of DaysYear Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec1982 31 31 31 31 31 31 31 31 31 31 31 311983 31 31 31 31 31 31 31 31 31 31 31 311984 31 31 31 31 31 31 31 31 31 31 31 311985 31 31 31 31 31 31 31 31 31 31 31 311986 31 31 31 31 31 31 31 31 31 31 31 31

Runoff DepthYear Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec1982 90 102 116 153 166 103 83 78 73 81 102 1311983 100 71 88 128 149 102 89 92 121 108 107 1031984 93 77 82 141 97 92 82 71 95 119 228 1611985 143 122 141 132 137 129 99 82 113 107 146 1271986 128 97 143 134 202 140 109 107 101 121 104 92

Rainfall Loss in Rainy Season1982 0.5301983 0.4491984 0.4321985 0.4311986 0.520

Average 0.473



Table 29 Probable Flood Hydrographs at Masang-2 Intake Weir Site

Cat

chm

ent A

rea

= 44

3 km

2U

nit:m

3/s

Tim

e(h

our)

PMF

400

200

150

100

8050

3020

105

32

014

1414

1414

1414

1414

1414

1414

134

012

511

410

910

310

093

8579

7061

5347

212

8044

640

238

436

034

732

029

026

823

119

516

714

33

2776

958

860

821

769

740

682

617

568

487

410

348

296

439

5213

5912

2011

6510

9110

4996

687

480

468

957

849

041

65

4344

1493

1341

1280

1198

1152

1061

959

883

756

634

537

456

640

6713

9812

5611

9911

2210

8099

489

982

770

959

450

442

87

3267

1125

1010

965

904

869

800

724

667

571

480

407

346

824

2683

875

371

967

464

859

754

049

842

735

930

626

09

1751

607

546

522

489

471

434

393

363

312

263

224

191

1012

1142

338

136

434

132

930

327

525

421

918

515

913

611

823

290

262

250

235

227

209

191

176

153

130

112

9712

560

200

181

173

163

157

146

133

124

108

9280

7013

382

140

127

121

115

111

103

9488

7767

5852

1419

275

6866

6361

5753

5044

3935

3215

8739

3635

3433

3230

2927

2423

2116

5026

2524

2423

2322

2120

1918

1817

2618

1818

1717

1717

1616

1615

1518

1615

1515

1515

1514

1414

1414

1419

1414

1414

1414

1414

1414

1414

14P

eak

4344

1493

1341

1280

1198

1152

1061

959

883

756

634

537

456

Ret

urn

Per

iod

(yea

r)



Table 30 Probable Floods under Various Schemes in Sumatra

Catchment

No Scheme River Province Area(km2) 2 20 100 200 1,000 10,000

1 Tampur-1 Kr. Tampur D.I. Aceh 2,025 2,870 3,590 7,4702 Teunom-1 Kr. Teunom D.I. Aceh 900 2,300 3,120 8,3903 Aceh-2 Kr. Aceh D.I. Aceh 323 1,030 1,470 3,5104 Lawe Alas-4 Lawe Alas D.I. Aceh 5,705 2,500 4,250 12,5005 Peusangan-4 Kr. Peusangan D.I. Aceh 945 1,6006 Lake Laut Tawar Kr. Peusangan D.I. Aceh 195 500 810 940 1,6707 Residual Basin-1 Kr. Peusangan D.I. Aceh 106 360 530 600 1,0208 Jambu Aye Kr. Jambu Aye D.I. Aceh 3,890 1,939 2,331 3,800 4,8509 Rubek Kr. Jambu Aye D.I. Aceh 93 142

10 Residual Basin-2 Kr. Peusangan D.I. Aceh 128 320 480 550 94011 Lalang S. Belawan N. Sumatera 254 250 410 61012 Tembakau S. Percut N. Sumatera 171 140 230 34013 Lausimeme S. Percut N. Sumatera 106 180 280 30014 Helvetia S. Deli N. Sumatera 341 280 530 69015 Namobatang S. Deli N. Sumatera 93 250 27016 Baru S. Serdang N. Sumatera 671 470 750 94017 Pulau Tagor S. Ular N. Sumatera 1,013 430 820 1,07018 Karai S. Ular N. Sumatera 500 500 56019 Brohol S. Padang N. Sumatera 759 390 720 94020 Rampah S. Belutu N. Sumatera 423 180 290 37021 Renun A. Renun N. Sumatera 139 580 740 820 960 1,90022 Wampu S. Wampu N. Sumatera 1,570 2,97023 Limang S. Wampu N. Sumatera 959 300 94024 Sipan Sihaporas Sipan Sihaporas N. Sumatera 196 269 1,80025 Batang Bayang-1 Bt. Bayang W. Sumatera 84 59026 Batang Bayang-2 Bt. Bayang W. Sumatera 36 34027 Muko-Muko Bt. Antokan W. Sumatera 248 44 74 93 12028 Masang-3 Bt. Masang W. Sumatera 993 1,136 2,204 2,878 3,168 3,851 4,854 10,41929 Merangin-5 Bt. Merangin Jambi 2,597 1,970 2,460 5,30030 Lake Kerinci Siulak Jambi 916 590 1,538 2,177 2,464 3,102 4,092 13,34731 Batang Hari Bt. Hari Jambi 4,452 1,937 4,192 5,603 6,205 7,60132 Batang Hari (Alt.) Bt. Hari Jambi 3,825 1,664 3,602 4,814 5,331 6,53133 Kiri-1 Bt. Kampar Riau 1,187 2,537 7,27434 Kiri-2 Bt. Kampar Riau 552 1,44635 Kapoernan Bt. Kampar Riau 699 2,18136 Kotapanjang Bt. Kampar Riau 3,337 1,183 1,624 8,000 11,40037 Upper Sinamar Bt. Indragiri Riau 3,180 3,180 8,38338 Sukam Bt. Indragiri Riau 360 1,75539 Lower Kuantan Bt. Indragiri Riau 7,453 10,04740 Ombilin Bt. Ombilin Riau 1,078 118 175 211 26341 Musi (Intake Dam) A. Musi S. Sumatera 587 240 530 720 780 1,010 1,31042 Musi (Regulation Dam) A. Musi S. Sumatera 30 79 138 175 190 226 27743 Martapura Way Komering S. Sumatera 4,260 1,300 1,900 2,200 2,300 2,700 6,30044 Lematang-4 A. Lematang S. Sumatera 1,321 1,870 2,430 5,50045 Mine Mouth Steam Plant A. Lematang S. Sumatera 3,667 6,63646 Ketaun-1 A. Ketaun Bengkulu 449 500 800 980 1,070 7,140

Masang-2 Bt. Masang W. Sumatera 443 456 883 1,198 1,341 4,344Source: Hydro Inventory Study, Sectral Report Vol.2 Hydrology, July 1997. Masang-3 HEPP, 1999.

Probable Peak Discharge (m3/sec)Return Period (year) PMF



Table 31 Calculations of Suspended Load in Masang River

No

Sam

plin

gD

ate

Wat

er L

evel

Qw

CQ

sR

emar

ksSi

te(m

)(m

3/s)

(mg/

L)(to

n/da

y)1

Inta

ke W

eir

2010

/10/

60.

8429

.02

422.

331,

058.

922

Inta

ke W

eir

2010

/10/

90.

6720

.83

1,65

4.33

2,97

7.32

3In

take

Wei

r20

10/1

0/22

0.59

15.4

831

,518

.00

42,1

54.4

4U

4In

take

Wei

r20

10/1

0/25

0.69

19.8

638

4.67

660.

065

Inta

ke W

eir

2010

/11/

50.

8426

.54

456.

671,

047.

176

Inta

ke W

eir

2010

/11/

210.

9334

.21

1,72

6.67

5,10

3.59

7In

take

Wei

r20

10/1

1/25

1.58

80.5

01,

804.

6712

,551

.84

8In

take

Wei

r20

10/1

2/5

0.88

30.9

61,

492.

333,

991.

909

Sipi

sang

AW

LR S

tatio

n20

10/1

2/21

0.20

15.0

768

.67

89.4

1D

10Si

pisa

ng A

WLR

Sta

tion

2010

/12/

250.

2417

.09

262.

3338

7.35

DLe

gend

U: T

he c

once

ntra

tion

valu

e is

not

relia

ble

and

not c

onsi

dere

d in

the

dete

rmin

atio

n of

the

susp

ende

d lo

ad ra

ting

curv

e.D

: Sam

plin

g w

as c

arrie

d ou

t at t

he S

ipis

ang

AW

LR S

tatio

n

and

not

con

side

red

in th

e de

term

inat

ion

of th

e su

spen

ded

load

ratin

g cu

rve.



Table 32 Water Quality Analysis of Masang River

No Water Quality Parameter Unit Sample-1 Sample-2 Sample-3

Date 2010/10/25 2010/11/25 2010/12/25Weather Clear Cloud Cloud

1 pH 8.09 8.11 8.112 Temperature ℃ 25.4 24.9 24.93 Total Hardness mg/l 123.7 131 1264 Temporary Hardness mg/l 52.58 93 975 Suspended Matter mg/lit 136 299 2956 Total Solid mg/lit 261 327 3437 Ignition Residue mg/lit 0.08 0.07 0.078 Permanganate Value as O2 mg/lit 9.69 7.24 3.559 Carbonates as CaCO3 mg/lit 0 10.74 8.06

10 Bicarbonates as CaCO3 mg/lit 135.52 115 14111 Calcium (Ca) mg/lit 37.48 41.64 39.8912 Magnesium (Mg) mg/lit 7.34 6.57 6.3713 Sodium (Na) mg/lit 8.36 11.52 9.914 Potassium (K) mg/lit 1.96 2.77 2.815 Iron (Fe) mg/lit 1.579 0.72 1.2816 Manganese (Mn) mg/lit <0.02 0.69 0.0717 Copper (Cu) mg/lit <0.001 0.008 0.00818 Turbidity NTU 41 37 5219 Color Pt-Co-Unit 20 10 kol 10 kol20 Electric Conductivity µ/Cm 254 313 30321 Aluminum (Al) mg/lit 1.35 1 1.4222 Silica (SiO2) mg/lit 46.52 17.7 2223 Lead (Pb) mg/lit 0.008 0.42 0.4224 Arsenic (As) mg/lit 0.0024 0.002 0.002525 Ammonium (NH4) mg/lit 0.784 <0.02 <0.0226 Albuminoid mg/lit <0.1 <0.1 <0.127 Nitrites (NO2) mg/lit 0.002 0.003 0.00728 Nitrates (NO3) mg/lit 0.516 0.432 0.66629 Sulfities (SO3) mg/lit 0.155 0.072 <0.0230 Sulfates (SO4) mg/lit 17.65 21.03 21.931 Chlorides (Cl) mg/lit 7.77 8.09 7.8732 Phosphates (PO4) mg/lit 0.049 <0.002 <0.00233 Oxygen (O2) mg/lit 7.31 6.79 7.1734 Carbon Dioxide (CO2) mg/lit 1.73 - -35 P-value as CaCO3 mg/lit 0.052 <0.02 < 0.00236 M-Value as CaCO3 mg/lit 25 24.8 24.8


JICA Project for the Master Plan Study of F-1 August, 2010 Hydropower Development in Indonesia

Figure 1 Location Map of Meteo-Hydrological Stations



Daily Rainfall Records

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

1 Maninjau 52B 22-0052-02

2 Limau Purut 52C 22-0052-03

3 Padang Panjang 53 22-0053-00

4 Bukit Tinggi 54 22-0054-00 1961-

5 Baso 54A 22-0054-01

6 Padang Mangatas 54C 22-0054-03 1965-

7 Payakumbuh 56 22-0056-00 1920-

8 Koto Tinggi 56A 22-0056-01

9 Suliki 56B 22-0056-02 1923-

10 Kota Baharu 57 22-0057-00

11 Bonjol 58C 22-0058-03

12 Jambak 58F 22-0058-06

13 Lubuk Sikaping 59 22-0059-00

Source: BMKG

Monthly Rainfall Records

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

1 Maninjau 52B 22-0052-02

2 Limau Purut 52C 22-0052-03

3 Padang Panjang 53 22-0053-00

4 Bukit Tinggi 54 22-0054-00 1961-

5 Baso 54A 22-0054-01

6 Padang Mangatas 54C 22-0054-03 1965-

7 Payakumbuh 56 22-0056-00 1920-

8 Koto Tinggi 56A 22-0056-01

9 Suliki 56B 22-0056-02 1923-

10 Kota Baharu 57 22-0057-00

11 Bonjol 58C 22-0058-03

12 Jambak 58F 22-0058-06

13 Lubuk Sikaping 59 22-0059-00


No. Station NameBMGID

HPPS2ID

RemarksHPPS2

IDStation NameBMGID

Remarks

No.

Year

Year

Figure 2 Availability of Climatic Records (1/2)



Daily Runoff Records

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

1 163-01-01 28years

Source: Pusair Bandung

Daily Water Level Records

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

1 163-01-01

Source: BPSDA Bukit Tinggi

Monthly Runoff Records

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

1 163-01-01

Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. Pusair Bandung.

Air Temperature

196

9

197

0

197

1

197

2

197

3

197

4

197

5

197

6

197

7

197

8

197

9

198

0

198

1

198

2

198

3

198

4

198

5

198

6

198

7

198

8

198

9

199

0

199

1

199

2

199

3

199

4

199

5

199

6

199

7

199

8

199

9

200

0

200

1

200

2

200

3

200

4

200

5

200

6

200

7

200

8

200

9

1 Tabing-Padang 03106 22-0043-01

Source: BMKG

Relative Humidity

196

9

197

0

197

1

197

2

197

3

197

4

197

5

197

6

197

7

197

8

197

9

198

0

198

1

198

2

198

3

198

4

198

5

198

6

198

7

198

8

198

9

199

0

199

1

199

2

199

3

199

4

199

5

199

6

199

7

199

8

199

9

200

0

200

1

200

2

200

3

200

4

200

5

200

6

200

7

200

8

200

9

1 Tabing-Padang 03106 22-0043-01

Source: BMKG

Sunshine Duration

196

9

197

0

197

1

197

2

197

3

197

4

197

5

197

6

197

7

197

8

197

9

198

0

198

1

198

2

198

3

198

4

198

5

198

6

198

7

198

8

198

9

199

0

199

1

199

2

199

3

199

4

199

5

199

6

199

7

199

8

199

9

200

0

200

1

200

2

200

3

200

4

200

5

200

6

200

7

200

8

200

9

1 Tabing-Padang 03106 22-0043-01

Source: BMKG

Wind Velocity

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

1 Tabing-Padang 03106 22-0043-01

Source: BMKG

Pan Evapolation

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

1 Lubuk Sikaping BMG

2 Tanjung Pati P3SA


: Complite Data: Incomplite Data

No. Station NameDPMA

ID

No. Station Name

HPPS2ID

Remarks

Remarks

Remarks

Remarks

Remarks

Year

HPPS2ID

HPPS2ID

No.DPMA

IDStation Name RemarksHPPS2

ID


HPPS2ID


No. Station Name

No. Station NameManagement

Body


Bt. Masang - Sipisang

01-164 -00-01

BMGID

Remarks

HPPS2ID Remarks


01-164 -00-01

Year


01-164 -00-01

DPMAID

HPPS2ID

Year

Year

Year

Year

Year

Year

Figure 3 Availability of Climatic Records (2/2)



Figure 4 Catchment Area of Masang-2 Intake Weir based on

1:50,000 map

B. Masang

S. Guntung

B. Sianok

B. Masang

B. A. Alahanpanjang

Masang-2 Intake Weir Site

Masang-2 Basin 443km2

Sipisang AWLR station

Power House Site

Final Report (Supporting_PreF/S) Part 16 Hydrological Analysis for Masang-2 HEPP


Monthly Mean Air Temperature

St. Tabing-Padang

25.0

25.5

26.0

26.5

27.0


Month

Tem

pera

ture

( ℃

)

Monthly Mean Relative HumiditySt. Tabing-Padang

79.0

80.0

81.0

82.0

83.0

84.0

85.0


Month

Hum

idity

( % )

Monthly Mean Sunshine DurationSt. Tabing-Padang

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0


Month

Dura

tion (

% )

Monthly Mean Wind VelocitySt. Tabing-Padang

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4


Month

Velo

city

( m

/s

)

Monthly Mean Pan EvaporationSt. Lubuk Sukaping

0.0

1.0

2.0

3.0

4.0

5.0

6.0


Month

Eva

pora

tion (

mm

/day

)

Monthly Mean Pan EvaporationSt. Tanjung Pati

0.0

1.0

2.0

3.0

4.0

5.0

6.0


Month

Eva

pora

tion (

mm

/day

)

Figure 5 Variations of Principal Climatic Data



Figure 6 Location Map of Hourly Rainfall Stations



Station Name: Gunung Melintang

0

20

40

60

80

100

120

140

160

0 1 2 3 4 5 6 7 8 9 10 11 12Time (hour)

Accumulated Hourly

Rainfall (mm)

Station Name: Maura Paiti

0

20

40

60

80

100

120

140

160

0 1 2 3 4 5 6 7 8 9 10 11 12Time (hour)

Accumulated Hourly

Rainfall (mm)

Station Name: Maninjau, Sungai Talang Barat, Solok Bio-Bio,Patir, Puar Datar, Halaban Dua

0

20

40

60

80

100

120

140

160

0 1 2 3 4 5 6 7 8 9 10 11 12Time (hour)

Accumulated Hourly

Rainfall (mm)

Figure 7 Accumulated Hourly Rainfall Curves



0

10

20

30

40

50

60

70

80

90

100

1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec

Dis

cha

rge (

m3/s)

1975

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1976

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1977

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1978

Figure 8 Daily Runoff Hydrograph (1/7)



0

10

20

30

40

50

60

70

80

90

100


Dis

charg

e (

m3/s)

1979

0

10

20

30

40

50

60

70

80

90

100


Dis

charg

e (

m3/s)

1980

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1981

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1982




0

10

20

30

40

50

60

70

80

90

100


Dis

charg

e (

m3/s)

1983

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1984

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1985

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1986




0

10

20

30

40

50

60

70

80

90

100


Dis

charg

e (

m3/s)

1987

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1990

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1991

0

10

20

30

40

50

60

70

80

90

100


Dis

char

ge (

m3/s)

1992




0

10

20

30

40

50

60

70

80

90

100


Dis

charg

e (

m3/s)

1993

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1995

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1996

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

1997




0

10

20

30

40

50

60

70

80

90

100


Dis

charg

e (

m3/s)

1998

0

10

20

30

40

50

60

70

80

90

100


Dis

charg

e (

m3/s)

1999

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

2000

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

2001




0

10

20

30

40

50

60

70

80

90

100


Dis

char

ge (

m3/s)

2005

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

2006

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

2007

0

10

20

30

40

50

60

70

80

90

100


Dis

cha

rge (

m3/s)

2008




0.00

0.50

1.00

1.50

2.00

2.50

3.00


Wat

er

Leve

l (m

)

2004

0.00

0.50

1.00

1.50

2.00

2.50

3.00


Wat

er

Leve

l (m

)

2005

0.00

0.50

1.00

1.50

2.00

2.50

3.00


Wat

er

Leve

l (m

)

2006

0.00

0.50

1.00

1.50

2.00

2.50

3.00


Wat

er

Leve

l (m

)

2007

Figure 15 Observed Daily Water Level Records (1/2)



0.00

0.50

1.00

1.50

2.00

2.50

3.00


Wat

er

Leve

l (m

)

2008

0.00

0.50

1.00

1.50

2.00

2.50

3.00


Wat

er

Leve

l (m

)

2009

Figure 16 Observed Daily Water Level Records (2/2)



-

20,000

40,000

60,000

80,000

- 20,000 40,000 60,000 80,000

Accumulation of average annual rainfall atsurrounding stations

Accu

mula

tion

of

annu

al r

ainfa

ll at

Koto

Tin

ggi st

atio

n

1971

1993

y = 0.656x

y = 1.6882x - 45901

-

20,000

40,000

60,000

80,000

- 20,000 40,000 60,000 80,000


Acc

um

ula

tion

of

annual

rai

nfa

ll at

Sulik

ist

atio

n

1971

1993

1988

1987

-

20,000

40,000

60,000

80,000

- 20,000 40,000 60,000 80,000


Accum

ulat

ion o

f an

nual

rai

nfa

ll at

Jam

bak

stat

ion

1971

1993

y = 0.6675x

y = 1.4072x - 19227

-

20,000

40,000

60,000

80,000

- 20,000 40,000 60,000 80,000


Accum

ulat

ion o

f an

nual

rai

nfa

ll at

Man

inja

ust

atio

n

1971

1993

19791978

Figure 17 Double Mass Curves of Rainfall Records



Figure 18 Thiessen Polygon



-

500

1,000

1,500

2,000

2,500

- 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

Annual Basin Mean Rainfall (mm)

Ann

ual R

unoff

Dept

h (m

m)

1993

1984

1976

19910mm

700mm

1500mm

Figure 19 Relationship between Annual Basin Mean Rainfall and Annual Runoff Depth at

Sipisang AWLR Station

700 mm

1,500 mm

0 mm

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500

Annual Basin Mean Rainfall (mm)

Ann

ual R

unof

f Dep

th (m

m)

Figure 20 Relationship between Annual Basin Mean Rainfall and Annual Runoff Depth of

Various River Basins in Sumatra



Figure 21 Concept of Composite Tank Model



Figure 22 Comparison of Observed and Simulated Monthly Runoff at Sipisang AWLR Station

0

10

20

30

40

50

60

70

1982/1

1982/7

1983/1

1983/7

1984/1

1984/7

1985/1

1985/7

1986/1

1986/7

0 100

200

300

400

500

600

700

Rai

n

Obs

erv

ed

Runoff

Sim

ula

ted

Runoff



Figure 23 Flow Duration Curve of Observed and Simulated Monthly Runoff at Sipisang AWLR Station

%O

bser

ved

Run

off

(m3/

s)Si

mul

ated

Run

off

(m3/

s)Er

ror

0%40

.39

36.4

510

.8%

5%28

.62

28.9

41.

1%10

%25

.94

26.0

40.

4%15

%25

.12

25.3

20.

8%20

%24

.38

24.2

20.

7%25

%23

.31

23.0

41.

2%30

%22

.63

21.3

36.

1%35

%21

.51

20.5

74.

6%40

%20

.72

20.0

43.

4%45

%19

.22

19.7

02.

5%50

%18

.91

19.3

42.

2%55

%18

.26

18.8

73.

2%60

%18

.03

18.5

22.

6%65

%17

.64

17.7

70.

7%70

%17

.18

17.1

10.

4%75

%16

.35

16.8

42.

9%80

%15

.92

16.3

02.

4%85

%14

.71

15.3

54.

2%90

%14

.47

14.7

11.

6%95

%13

.66

14.0

02.

4%10

0%12

.59

12.1

93.

3%

05

10

15

20

25

30

35

40

45

50

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Discharge (m3/s)

Obs

erv

ed

Runoff

Sim

ula

ted

Runoff



Figure 24 Simulated Long-term Monthly Runoff at Sipisang AWLR Station

0

10

20

30

40

50

60

70

1973/1

1974/1

1975/1

1976/1

1977/1

1978/1

1979/1

1980/1

1981/1

1982/1

1983/1

1984/1

1985/1

1986/1

1987/1

1988/1

1989/1

1990/1

1991/1

1992/1

1993/1

0 100

200

300

400

500

600

700

Rai

n

Obs

erv

ed

Runoff

Sim

ula

ted

Runoff



Figure 25 Flow Duration Curve of Estimated Monthly Runoff at Sipisang AWLR Station

%O

bser

ved

and

Sim

ulat

edR

unof

f (m

3/s)

0%62

.84

5%30

.28

10%

26.6

915

%24

.38

20%

22.9

825

%21

.85

30%

20.5

135

%19

.39

40%

18.8

245

%18

.17

50%

17.6

655

%17

.18

60%

16.5

465

%16

.00

70%

15.2

275

%14

.57

80%

13.7

185

%12

.86

90%

12.0

395

%11

.01

100%

6.78

aver

age

18.9

4

05101520253035404550

00.

10.

20.

30.

40.

50.

60.

70.

80.

91

Discharge (m3/s)

Obs

erve

d an

d Si

mul

ated

Run

off



Figure 26 Flow Duration Curve of Estimated Daily Runoff at Masang-2 Intake Weir Site

Prob

abili

tyEs

timat

ed R

unof

f(%

)(m

3/s)

0%78

.99

5%31

.32

10%

26.3

115

%22

.51

20%

21.4

325

%20

.29

30%

18.9

135

%18

.05

40%

17.3

545

%16

.73

50%

16.1

955

%15

.57

60%

15.2

965

%14

.55

70%

13.8

175

%13

.06

80%

12.3

185

%11

.48

90%

10.9

995

%10

.03

100%

6.32

Ave

rage

17.6

7

Mas

ang-

2 In

take

Wei

r Site

05101520253035404550

00.

10.

20.

30.

40.

50.

60.

70.

80.

91

Prob

abili

ty o

f Exc

eede

nce

Runoff (m3/s)



Figure 27 Location Map of Water Level Observation and Discharge Measurement



0.0

0.5

1.0

1.5

2.0

2010/10/1 2010/10/16 2010/10/31 2010/11/15 2010/11/30 2010/12/15 2010/12/30

Wat

er L

evel

(m)

Maximum Water Level2.01m 2010/11/26 6:00

Minimum Water Level0.55m 2010/12/23

Average Water Level0.75m

0

20

40

60

80

100

120

140

160

180

2010/10/1 2010/10/16 2010/10/31 2010/11/15 2010/11/30 2010/12/15 2010/12/30

Run

off (

m3/

s)

Maximum Runoff156.61 m3/s 2010/11/26 6:00

Minimum Runoff13.60 m3/s 2010/12/23

Average Runoff25.68 m3/s

Discharge MeasurementEstimated Runoff withH-Q Rating Curve

Figure 28 Result of Water Level Observation and Hydrograph Calculated with H-Q Rating

Curve



0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0 20 40 60 80 100 120 140

Discharge (m3/s)

Wat

er L

evel

(m)

ObservationH-Q Rating Curve

Q=36.55(H+0.06)^2

Figure 29 H-Q Rating Curve



Total Rainfall Depth >= 50mm

5%

13%

29%

48%

63%

73%

100%

94%89%87%

84%

2%0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8 9 10 11 12

Time Duration (Hour)

Number of Data

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Total Rainfall Depth >= 100mm

0% 0% 0%

80% 80% 80% 80%

100% 100%

80%

40%

20%

0

1

2

3

1 2 3 4 5 6 7 8 9 10 11 12

Time Duration (Hour)

Number of Data

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Figure 30 Histogram of Rainfall Duration



0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1 2 3 4 5 6

Time (hour)

Accumulated Rainfall (%)

Design Pattern

Design Hyetograph

0%

10%

20%

30%

40%

50%

1 2 3 4 5 6

Time (hour)

Rainfall (%)

Figure 31 Accumulated Hourly Rainfall Pattern around Masang River Basin and Design Hyetograph



0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0 50 100 150 200 250

Point Rainfall Depth (mm)

Area Reduction Factor

Figure 32 Area Reduction Factor for Masang River Basin



Figure 33 Frequency Curves of Probable Daily Rainfall at Payakumbuh station



Source : Operational Hydrology Report No. 1Manual for Estimation of Probable Maximum PrecipitationPage 97, World Meteorological Organization, 1973

70

75

80

85

90

95

100

105

110

0.7 0.75 0.8 0.85 0.9 0.95 1Xn-m / Xn

X n a

djus

tmen

t fac

tor (

%)

10Length of record (years)15

20

3050

Figure 34 Adjustment of Mean of Annual Series for Maximum Observed Rainfall




20

30

40

50

60

70

80

90

100

110

120

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1Sn-m / Sn

S n a

djus

tmen

t fac

tor (

%)

10

Length of record (years)15

3050

Figure 35 Adjustment of Standard Deviation of Annual Series for Maximum Observed Rainfall




100

105

110

115

120

125

130

10 15 20 25 30 35 40 45 50 55

Length of Record (years)

Adj

ustm

ent F

acto

r (%

)

Standard Deviation

Mean

Figure 36 Adjustment of Mean and Standard Deviation of Annual Series for Length of Record



5

10

15

20

0 50 100 150 200 250 300 350 400 450 500 550 600

Mean Annual Rainfall (mm)

Km Duration

24 hours6 hours

1 hour

5 min

Figure 37 Km as a Function of Rainfall Duration and Mean of Annual Series

Source : Operational Hydrology Report No. 1Manual for Estimation of Probable Maximum PrecipitationPages 96 &100, World Meteorological Organization, 1973

98

100

102

104

106

108

110

112

114

0 4 8 12 16 20 24

Number of Observational Units

Adj

ustm

ent F

acto

r

Figure 38 Adjustment of Fixed Interval Precipitation Amounts for Number of Observational Units within the Interval



Slope

-

500

1,000

1,500

2,000

2,500

3,000

- 10,000 20,000 30,000 40,000 50,000 60,000

Distance (m)

Height (m)

Tc=5.8hrTc=0.4hr

Figure 39 Slope of Masang River

0

5

10

15

20

25

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time (hour)

Discharge (m3/s)

Figure 40 SCS Unit Hydrograph at Masang-2 Intake Weir Site



Figure 41 Daily Runoff Hydrograph at Sipisang AWLR Station

Daily Runoff Record as Sipisang Station

0

10

20

30

40

50

60

70

80

90

1982/1/1

1982/2/11982/3/1

1982/4/11982/5/1

1982/6/11982/7/1

1982/8/1

1982/9/11982/10/1

1982/11/11982/12/1

1983/1/11983/2/11983/3/1

1983/4/11983/5/1

1983/6/11983/7/1

1983/8/1

1983/9/11983/10/1

1983/11/11983/12/1

1984/1/1

1984/2/11984/3/1

1984/4/11984/5/1

1984/6/11984/7/1

1984/8/1

1984/9/11984/10/1

1984/11/11984/12/1

1985/1/11985/2/11985/3/11985/4/1

1985/5/11985/6/1

1985/7/11985/8/1

1985/9/11985/10/1

1985/11/11985/12/1

1986/1/1

1986/2/11986/3/1

1986/4/11986/5/1

1986/6/11986/7/1

1986/8/11986/9/1

1986/10/11986/11/1

1986/12/1

Dischatge (m3/s)



Figure 42 Probable Flood Hydrographs at Masang-2 Intake Weir Site

0

500

1000

1500

2000

2500

3000

3500

4000

4500

01

23

45

67

89

1011

1213

1415

1617

1819

Tim

e (h

our)

Discharge (m3/s)

PM

F40

020

015

010

080 50 30 20 10 5 3 2



Probable Maximum Flood

10

100

1,000

10,000

100,000

10 100 1,000 10,000 100,000Catchment Area (km2)

Floo

d P

eak

Dis

char

ge (m

3/s)

PMFC=92Masang-2 PMF

Return Period = 200 year

10

100

1,000

10,000

100,000


Floo

d P

eak

Dis

char

ge (m

3/s)

200C=28Masagn-2 200

Figure 43 Relationship between Probable Peak Discharge and Catchment Area in Sumatra (1/3)




10

100

1,000

10,000


Floo

d P

eak

Dis

char

ge (m

3/s)

100C=25Masagn-2 100


10

100

1,000

10,000


Floo

d P

eak

Dis

char

ge (m

3/s)

20C=19Masagn-2 20





10

100

1,000

10,000


Floo

d P

eak

Dis

char

ge (m

3/s)

2C=10Masagn-2 2




Figure 46 Catchment Area of Regulating Pond based on 1:10,000 Map



Figure 47 Catchment Area of Power House Site based on 1:250,000 Map

B. Masang

B. A. Alahanpanjang

Power House Site

Intake Weir Site

Masang-2 Basin 443.0 km2

Alahanpanjang Basin 424.1 km2

Sub Basin 52.4 km2



Figure 48 Sieve Analysis of Suspended Load

0%10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.01

0.10

1.00

10.0

0

Gra

in S

ize

(mm

)

%

Inta

ke06

-Okt

-10

Inta

ke06

-Okt

-10

Inta

ke06

-Okt

-10

Inta

ke09

-Okt

-10

Inta

ke09

-Okt

-10

Inta

ke09

-Okt

-10

Inta

ke22

-Okt

-10

Inta

ke22

-Okt

-10

Inta

ke22

-Okt

-10

Inta

ke25

-Okt

-10

Inta

ke25

-Okt

-10

Inta

ke25

-Okt

-10

Inta

ke05

-Nop

-10

Inta

ke05

-Nop

-10

Inta

ke05

-Nop

-10

Inta

ke21

-Nop

-10

Inta

ke21

-Nop

-10

Inta

ke21

-Nop

-10

Inta

ke25

-Nop

-10

Inta

ke25

-Nop

-10

Inta

ke25

-Nop

-10

Inta

ke05

-Des

-10

Inta

ke05

-Des

-10

Inta

ke05

-Des

-10

Sip

isan

g21-

Des

-10

Sip

isan

g21-

Des

-10

Sip

isan

g21-

Des

-10

Sip

isan

g25-

Des

-10

Sip

isan

g25-

Des

-10

Sip

isan

g25-

Des

-10



y = 5.4615x1.7812

1

10

100

1,000

10,000

100,000

1 10 100

Runoff, Qw (m3/s)

Sus

pend

ed L

oad,

Qs

(ton/

day)

Adopted Not Adopted

Figure 49 Suspended Load Rating Curve

Part 17 Supplemental Financial Evaluation for Simanggo-2 HEPP

Supplemental Financial Evaluation for Simanggo-2

1

SUPPLEMENTAL FINANCIAL EVALUATION FOR SIMANGGO-2

1. INTRODUCTION

This paper is a supplement to the Main Report on the Project for the Master Plan Study of Hydropower Development in Indonesia, hereinafter referred to as the Main Report. It is to provide an additional financial evaluation in the Simanggo-2 Hydropower Project, which focuses the pseudo electricity selling price governing the project’s revenue. This paper applies the actual electricity sales by PLN to the project revenue, while the Main Report used a shadow electricity tariff that includes the Government subsidy granted to PLN.

2. FINANCIAL EVALUATION

2.1 METHODOLOGY, ASSUMPTIONS, AND FINANCIAL COST

The methodology used, the assumptions set, and financial cost assumed are exactly same as those in the Main Report. The financial capital expenditure (CAPEX) applied for the Simanggo-2 Hydropower Project is US$209 million, excluding costs required for the feasibility study.

2.2 FINANCIAL BENEFIT

2.2.1 Electricity Tariff

The Main Report has chosen a shadow tariff US¢10.63/kWh (US¢7.48/kWh of the selling price and US¢3.15/kWh of the Government subsidy) as of 2010, while this paper applies the actual electricity selling price US¢7.48/kWh as of 2010 without the Government subsidy, as compared in Table 2-1.

Table 2-1 Electricity Sales and Subsidy

Year Electricity Sales Subsidy Sum Electricity

(GWh) Tariff P Tariff S

Rp T US$M Rp T US$M US$M US¢/kWh US¢/kWh2002 39,018 4,335 4,739 527 4,862 108,360 4.001 4.4872003 49,810 5,534 4,097 455 5,990 113,020 4.897 5.3002004 58,232 6,470 3,470 386 6,856 120,244 5.381 5.7022005 63,246 7,027 12,511 1,390 8,417 127,370 5.517 6.6092006 70,735 7,859 32,909 3,657 11,516 133,108 5.905 8.6522007 76,286 8,476 36,605 4,067 12,543 142,441 5.951 8.8062008 84,250 9,361 78,577 8,731 18,092 149,437 6.264 12.1072009 90,172 10,019 53,720 5,969 15,988 156,797 6.390 10.1972010* N/A N/A 55,100 6,122 N/A 194,459 7.479 10.6272011* N/A N/A 41,000 4,556 N/A 201,977 7.689 9.945 Electricity = Electricity sold by PLN Tariff P = average electricity charge without subsidy Tariff S = electricity charge with subsidy * Estimations for “Electricity Sold” and “Tariff P” based on the past trends in 2005 to 2009. Rp.9,000/US$ is used for Rupiah to US$ conversion. Source: Study Team based on PLN Statistics 2009 and MOF data

The electricity tariff is assumed to be escalated as same as it was done in the past. The trend line of the past electricity tariff suggests that the electricity tariff would be increased by US¢0.2105 every year as seen in Figure 2-1. The electricity tariff would be then 9.16US¢/kWh in 2018, the first operating year.


2

y = 0.2105x + 5.3739

0

2

4

6

8

10

2005 2006 2007 2008 2009 2010 2011 2012 2013

Tarif

f (U

S¢/

kWh)

Year

Source: Study Team

Figure 2-1 Electricity Tariff Projection

2.2.2 Project Revenue

The project revenue is of the electricity tariff multiplied by the expected electricity sold. The first operating year revenue as of 2018 is then;

US$33.2 mill./year = US$0. 0916/kWh x 362 GWh/year

Where 362 GWh/year is the net annual energy.

Benefit from Certified Emission Reduction (CER) is exactly same as discussed in the Main Report.

2.3 FINANCIAL ANALYSIS

2.3.1 Interest Free Cash Flow

An interest free cash flow here evaluates the project’s profitability without financing charges but with income tax. The financial stream is tabulated in Table 2-2. The key indicators in present worth are:

NPVP = US$17.6 million FIRR = 11.1%

B/C = 1.08

The FIRR computed is much greater than 2.0% of the hurdle rate, and therefore PLN as the project-operating entity will be able to make profit from the project with high probability. However, this FIRR does not reach a magnificent level, say 13%, which may make foreign investors keen for investment in the country.


3

Table 2-2 Interest Free Financial Stream US$ million GWh

CAPEX O&M Tax Sub-total Sales CER Sub-total2011 -6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 02012 -5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 02013 -4 2.02 0.00 0.00 2.02 0.00 0.00 0.00 -2.02 02014 -3 17.72 0.00 0.00 17.72 0.00 0.00 0.00 -17.72 02015 -2 55.43 0.00 0.00 55.43 0.00 0.00 0.00 -55.43 02016 -1 89.38 0.00 0.00 89.38 0.00 0.00 0.00 -89.38 02017 0 44.90 0.00 0.00 44.90 0.00 0.00 0.00 -44.90 02018 1 0.00 5.61 5.40 11.01 33.19 1.68 34.87 23.86 3622019 2 0.00 5.79 5.55 11.34 33.95 1.68 35.63 24.29 3622020 3 0.00 5.98 5.69 11.67 34.71 1.68 36.40 24.73 3622021 4 0.00 6.17 5.83 12.01 35.48 1.68 37.16 25.15 3622022 5 0.00 6.37 5.97 12.35 36.24 1.68 37.92 25.57 3622023 6 0.00 6.58 6.11 12.70 37.00 1.68 38.68 25.99 3622024 7 0.00 6.80 6.25 13.05 37.76 1.68 39.45 26.40 3622025 8 0.00 7.03 6.41 13.44 38.53 1.68 40.21 26.77 3622026 9 0.00 7.26 6.58 13.84 39.29 1.68 40.97 27.13 3622027 10 0.00 7.51 6.74 14.24 40.05 1.68 41.73 27.49 3622028 11 0.00 7.76 6.89 14.66 40.81 1.68 42.50 27.84 3622029 12 0.00 8.03 7.05 15.08 41.58 1.68 43.26 28.18 3622030 13 0.00 8.30 7.20 15.50 42.34 1.68 44.02 28.52 3622031 14 0.00 8.59 7.35 15.94 43.10 1.68 44.78 28.84 3622032 15 0.00 8.88 7.50 16.38 43.86 1.68 45.55 29.16 3622033 16 0.00 9.19 7.64 16.84 44.63 1.68 46.31 29.47 3622034 17 0.00 9.52 7.79 17.30 45.39 1.68 47.07 29.77 3622035 18 0.00 9.85 7.92 17.77 46.15 1.68 47.83 30.06 3622036 19 0.00 10.20 8.06 18.26 46.91 1.68 48.60 30.34 3622037 20 0.00 10.56 8.19 18.75 47.68 1.68 49.36 30.61 3622038 21 0.00 10.94 8.32 19.26 48.44 1.68 50.12 30.86 3622039 22 0.00 11.34 8.44 19.78 49.20 1.68 50.88 31.11 3622040 23 0.00 11.75 8.56 20.31 49.96 1.68 51.65 31.34 3622041 24 0.00 12.18 8.67 20.85 50.73 1.68 52.41 31.56 3622042 25 0.00 12.62 8.78 21.40 51.49 1.68 53.17 31.77 3622043 26 0.00 13.09 8.89 21.98 52.25 1.68 53.93 31.96 3622044 27 0.00 13.57 8.99 22.56 53.01 1.68 54.69 32.13 3622045 28 0.00 14.08 9.08 23.16 53.78 1.68 55.46 32.30 3622046 29 0.00 14.61 9.17 23.78 54.54 1.68 56.22 32.44 3622047 30 0.00 15.16 9.26 24.41 55.30 1.68 56.98 32.57 3622048 31 0.00 14.14 0.00 14.14 0.00 0.00 0.00 -14.14 02049 32 0.00 16.33 9.00 25.33 56.83 1.68 58.51 33.18 3622050 33 0.00 16.95 9.03 25.98 57.59 1.68 59.27 33.29 3622051 34 0.00 17.61 9.06 26.66 58.35 1.68 60.03 33.37 3622052 35 0.00 18.29 9.08 27.36 59.11 1.68 60.79 33.43 3622053 36 0.00 19.00 9.09 28.09 59.87 1.68 61.56 33.47 3622054 37 0.00 19.74 9.10 28.83 60.64 1.68 62.32 33.49 3622055 38 0.00 20.51 9.09 29.61 61.40 1.68 63.08 33.48 3622056 39 0.00 21.32 9.08 30.40 62.16 1.68 63.84 33.44 3622057 40 0.00 22.16 9.06 31.23 62.92 1.68 64.61 33.38 3622058 41 0.00 23.05 9.03 32.08 63.69 1.68 65.37 33.29 3622059 42 0.00 23.97 8.99 32.96 64.45 1.68 66.13 33.17 3622060 43 0.00 24.93 8.94 33.87 65.21 1.68 66.89 33.02 3622061 44 0.00 25.93 8.88 34.81 65.97 1.68 67.66 32.84 3622062 45 0.00 26.98 8.81 35.79 66.74 1.68 68.42 32.63 3622063 46 0.00 28.08 8.73 36.81 67.50 1.68 69.18 32.37 3622064 47 0.00 29.23 8.63 37.86 68.26 1.68 69.94 32.09 3622065 48 0.00 30.43 8.52 38.95 69.02 1.68 70.71 31.76 3622066 49 0.00 31.68 8.40 40.08 69.79 1.68 71.47 31.39 3622067 50 -56.16 32.99 8.26 -14.91 70.55 1.68 72.23 87.14 362

153.29 748.64 393.06 1295.00 2537.40 82.42 2619.82 1324.82 17,748133.42 45.97 37.27 216.66 224.94 9.36 234.30 17.64 –

13.40 4.62 3.74 21.76 22.59 0.94 23.53 1.77 –NPVP = 17.64 FIRR = 11.12% B/C = 1.08 Cost =

PV stands for a present value discounted by 10% p.a.Annu stands for an annualized value of respective present value.

TotalPV

Annu

YearCost Benefit Net

Benefit

Source: Study Team

EnergySupply

US¢6.0/kWh

2.3.2 Return on Investment

Assuming the loan conditions exactly same as the Main Report in Table 2-3, the return on investment was computed as given in Table 2-4 by using a DCF model. The net present value and rate of return are:


4

NPVI = US$82.4 million ROI = 23.9%

Table 2-3 Loan Conditions Assumed for Financial Cash Flow

Lender Interest Rate (p.a)

Front-end fee

Commitment fee (p.a)

Graceperiod

Repay period

Loan share

Bilateral Institution 1.90% 0.00% 0.75% 7 years 25 years 75%

Notes 1. The front-end fee will be charged only at the time of loan agreement. The commitment fee is charged against unused loan amount and will decrease gradually and end at null when the loan amount is fully disbursed.

2. Interest rate is assumed constant and being composed of 1.4% p.a. of JICA’s standard rate for medium income countries plus 0.5% p.a. of onlending spread by MOF.

3. Grace period includes 4 years of construction. 4. No insurance is counted. Source: Study Team

The project can be evaluated financially feasible from a long term view. The breakeven is 3 years after commissioning. Because no revenue is expected in the replacement year scheduled 30 years after commissioning, however, the project will not be able to fulfill the debt service obligation in the same year. As an enough return is expected, the project can easily overcome the debt service issue. For example, if 4% of the annual net profit is deposited every year into a saving account, the project will easily be able to have enough cash when no revenue is expected due to machine replacement.

-60

-40

-20

0

20

40

60

80

2018

2021

2024

2027

2030

2033

2036

2039

2042

2045

2048

2051

2054

2057

2060

2063

2066

Reve

nue a

nd C

ost (

US$

mill

.)

Years

Tax

Interest

Principal

O&M

Revenue

PAT

Source: Study Team

Figure 2-2 Cash Inflow and Outflow

Assuming the aforementioned explicit savings for the replacement cost, DSCR and LLCR can be raised as:

Minimum DSCR = 1.7 > 1.0 Minimum LLCR = 2.5 > 1.0

Now, all of the indicators show enough numbers and therefore one can evaluate the hydropower project in question is financially viable. The profit and loss calculations are given in Table 2-5.


5

Table 2-4 Financial Cash Flow for ROI US$ million

Cash GenerationSales Residual O&M Interest Repay Tax Net Sum

2011 -6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.002012 -5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.002013 -4 1.83 0.00 0.00 0.00 0.01 0.00 0.00 -1.83 -1.832014 -3 15.98 0.00 0.00 0.00 0.05 0.00 0.00 -16.03 -17.862015 -2 29.42 0.00 0.00 0.00 0.73 0.00 0.00 -30.15 -48.002016 -1 0.00 0.00 0.00 0.00 2.90 0.00 0.00 -2.90 -50.902017 0 0.00 0.00 0.00 0.00 3.44 0.00 0.00 -3.44 -54.342018 1 0.00 33.19 0.00 5.61 3.10 0.00 5.40 20.76 -33.582019 2 0.00 33.95 0.00 5.79 3.10 0.00 5.55 21.20 -12.392020 3 0.00 34.71 0.00 5.98 3.10 0.00 5.69 21.63 9.242021 4 0.00 35.48 0.00 6.17 3.10 0.00 5.83 22.05 31.302022 5 0.00 36.24 0.00 6.37 3.10 0.00 5.97 22.47 53.772023 6 0.00 37.00 0.00 6.58 3.10 0.00 6.11 22.89 76.662024 7 0.00 37.76 0.00 6.80 3.10 0.00 6.25 23.30 99.962025 8 0.00 38.53 0.00 7.03 2.97 6.52 6.41 17.27 117.232026 9 0.00 39.29 0.00 7.26 2.85 6.52 6.58 17.76 134.992027 10 0.00 40.05 0.00 7.51 2.73 6.52 6.74 18.24 153.232028 11 0.00 40.81 0.00 7.76 2.60 6.52 6.89 18.72 171.952029 12 0.00 41.58 0.00 8.03 2.48 6.52 7.05 19.18 191.132030 13 0.00 42.34 0.00 8.30 2.35 6.52 7.20 19.64 210.772031 14 0.00 43.10 0.00 8.59 2.23 6.52 7.35 20.09 230.872032 15 0.00 43.86 0.00 8.88 2.11 6.52 7.50 20.53 251.402033 16 0.00 44.63 0.00 9.19 1.98 6.52 7.64 20.97 272.372034 17 0.00 45.39 0.00 9.52 1.86 6.52 7.79 21.39 293.752035 18 0.00 46.15 0.00 9.85 1.73 6.52 7.92 21.80 315.562036 19 0.00 46.91 0.00 10.20 1.61 6.52 8.06 22.21 337.762037 20 0.00 47.68 0.00 10.56 1.49 6.52 8.19 22.60 360.362038 21 0.00 48.44 0.00 10.94 1.36 6.52 8.32 22.98 383.342039 22 0.00 49.20 0.00 11.34 1.24 6.52 8.44 23.35 406.682040 23 0.00 49.96 0.00 11.75 1.12 6.52 8.56 23.70 430.392041 24 0.00 50.73 0.00 12.18 0.99 6.52 8.67 24.05 454.432042 25 0.00 51.49 0.00 12.62 0.87 6.52 8.78 24.38 478.812043 26 0.00 52.25 0.00 13.09 0.74 6.52 8.89 24.69 503.502044 27 0.00 53.01 0.00 13.57 0.62 6.52 8.99 24.99 528.502045 28 0.00 53.78 0.00 14.08 0.50 6.52 9.08 25.28 553.772046 29 0.00 54.54 0.00 14.61 0.37 6.52 9.17 25.55 579.322047 30 0.00 55.30 0.00 15.16 0.25 6.52 9.26 25.80 605.122048 31 0.00 0.00 0.00 14.14 0.12 6.52 0.00 -20.79 584.342049 32 0.00 56.83 0.00 16.33 0.00 6.52 9.00 26.66 611.002050 33 0.00 57.59 0.00 16.95 0.00 0.00 9.03 33.29 644.282051 34 0.00 58.35 0.00 17.61 0.00 0.00 9.06 33.37 677.652052 35 0.00 59.11 0.00 18.29 0.00 0.00 9.08 33.43 711.082053 36 0.00 59.87 0.00 19.00 0.00 0.00 9.09 33.47 744.552054 37 0.00 60.64 0.00 19.74 0.00 0.00 9.10 33.49 778.042055 38 0.00 61.40 0.00 20.51 0.00 0.00 9.09 33.48 811.512056 39 0.00 62.16 0.00 21.32 0.00 0.00 9.08 33.44 844.952057 40 0.00 62.92 0.00 22.16 0.00 0.00 9.06 33.38 878.342058 41 0.00 63.69 0.00 23.05 0.00 0.00 9.03 33.29 911.632059 42 0.00 64.45 0.00 23.97 0.00 0.00 8.99 33.17 944.802060 43 0.00 65.21 0.00 24.93 0.00 0.00 8.94 33.02 977.832061 44 0.00 65.97 0.00 25.93 0.00 0.00 8.88 32.84 1,010.672062 45 0.00 66.74 0.00 26.98 0.00 0.00 8.81 32.63 1,043.292063 46 0.00 67.50 0.00 28.08 0.00 0.00 8.73 32.37 1,075.672064 47 0.00 68.26 0.00 29.23 0.00 0.00 8.63 32.09 1,107.752065 48 0.00 69.02 0.00 30.43 0.00 0.00 8.52 31.76 1,139.512066 49 0.00 69.79 0.00 31.68 0.00 0.00 8.40 31.39 1,170.902067 50 0.00 70.55 56.16 32.99 0.00 0.00 8.26 87.14 1,258.04

47.22 2,537.40 56.16 748.64 65.97 163.03 393.06 1,258.04 –33.61 224.94 0.27 45.97 18.18 17.15 37.27 82.39 –

3.38 22.59 0.03 4.62 1.83 1.72 3.74 8.28 –NPVI = 82.39 ROI = 23.95% Source: Study Team


PVAnnu

BenefitInvestYear

Total


6

Table 2-5 Profit and Loss US$ million

2011 -6 0.00 0.00 0.00 0.00 0.00 0.00 0.002012 -5 0.00 0.00 0.00 0.00 0.00 0.00 0.002013 -4 0.00 0.01 0.00 0.00 -2.03 0.00 -2.032014 -3 0.00 0.05 0.00 0.00 -17.77 0.00 -17.772015 -2 0.00 0.73 0.00 0.00 -56.15 0.00 -56.152016 -1 0.00 2.90 0.00 0.00 -92.28 0.00 -92.282017 0 0.00 3.44 0.00 0.00 -48.34 0.00 -48.342018 1 33.19 3.10 5.61 4.55 21.61 5.40 16.21 7.06 3.402019 2 33.95 3.10 5.79 4.55 22.19 5.55 16.64 7.47 3.362020 3 34.71 3.10 5.98 4.55 22.77 5.69 17.07 7.88 3.322021 4 35.48 3.10 6.17 4.55 23.33 5.83 17.50 8.29 3.272022 5 36.24 3.10 6.37 4.55 23.90 5.97 17.92 8.71 3.232023 6 37.00 3.10 6.58 4.55 24.45 6.11 18.34 9.13 3.192024 7 37.76 3.10 6.80 4.55 24.99 6.25 18.74 9.56 3.142025 8 38.53 2.97 7.03 4.55 25.65 6.41 19.24 3.26 3.092026 9 39.29 2.85 7.26 4.55 26.30 6.58 19.73 3.42 3.152027 10 40.05 2.73 7.51 4.55 26.95 6.74 20.21 3.58 3.212028 11 40.81 2.60 7.76 4.55 27.58 6.89 20.68 3.75 3.272029 12 41.58 2.48 8.03 4.55 28.20 7.05 21.15 3.92 3.342030 13 42.34 2.35 8.30 4.55 28.81 7.20 21.61 4.10 3.412031 14 43.10 2.23 8.59 4.55 29.41 7.35 22.06 4.28 3.502032 15 43.86 2.11 8.88 4.55 30.00 7.50 22.50 4.47 3.592033 16 44.63 1.98 9.19 4.55 30.58 7.64 22.93 4.67 3.692034 17 45.39 1.86 9.52 4.55 31.14 7.79 23.36 4.87 3.802035 18 46.15 1.73 9.85 4.55 31.69 7.92 23.77 5.08 3.922036 19 46.91 1.61 10.20 4.55 32.23 8.06 24.17 5.30 4.072037 20 47.68 1.49 10.56 4.55 32.75 8.19 24.56 5.53 4.232038 21 48.44 1.36 10.94 4.55 33.26 8.32 24.95 5.76 4.422039 22 49.20 1.24 11.34 4.55 33.75 8.44 25.31 6.00 4.652040 23 49.96 1.12 11.75 4.55 34.23 8.56 25.67 6.25 4.922041 24 50.73 0.99 12.18 4.55 34.69 8.67 26.01 6.51 5.252042 25 51.49 0.87 12.62 4.55 35.13 8.78 26.34 6.78 5.662043 26 52.25 0.74 13.09 4.55 35.55 8.89 26.66 7.05 6.182044 27 53.01 0.62 13.57 4.55 35.95 8.99 26.96 7.34 6.892045 28 53.78 0.50 14.08 4.55 36.33 9.08 27.25 7.63 7.872046 29 54.54 0.37 14.61 4.55 36.69 9.17 27.52 7.94 9.342047 30 55.30 0.25 15.16 4.55 37.02 9.26 27.77 8.25 11.792048 31 0.00 0.12 14.14 2.18 -16.45 0.00 -16.45 1.84 18.392049 32 56.83 0.00 16.33 6.20 35.98 9.00 26.99 4.77 34.802050 33 57.59 0.00 16.95 6.20 36.12 9.03 27.09 n.a. n.a.2051 34 58.35 0.00 17.61 6.20 36.23 9.06 27.17 n.a. n.a.2052 35 59.11 0.00 18.29 6.20 36.31 9.08 27.23 n.a. n.a.2053 36 59.87 0.00 19.00 6.20 36.36 9.09 27.27 n.a. n.a.2054 37 60.64 0.00 19.74 6.20 36.39 9.10 27.29 n.a. n.a.2055 38 61.40 0.00 20.51 6.20 36.37 9.09 27.28 n.a. n.a.2056 39 62.16 0.00 21.32 6.20 36.33 9.08 27.25 n.a. n.a.2057 40 62.92 0.00 22.16 6.20 36.25 9.06 27.19 n.a. n.a.2058 41 63.69 0.00 23.05 6.20 36.13 9.03 27.10 n.a. n.a.2059 42 64.45 0.00 23.97 6.20 35.97 8.99 26.98 n.a. n.a.2060 43 65.21 0.00 24.93 6.20 35.77 8.94 26.83 n.a. n.a.2061 44 65.97 0.00 25.93 6.20 35.53 8.88 26.65 n.a. n.a.2062 45 66.74 0.00 26.98 6.20 35.24 8.81 26.43 n.a. n.a.2063 46 67.50 0.00 28.08 6.20 34.90 8.73 26.18 n.a. n.a.2064 47 68.26 0.00 29.23 6.20 34.52 8.63 25.89 n.a. n.a.2065 48 69.02 0.00 30.43 6.20 34.08 8.52 25.56 n.a. n.a.2066 49 69.79 0.00 31.68 6.20 33.59 8.40 25.19 n.a. n.a.2067 50 70.55 0.00 32.99 6.20 33.04 8.26 24.78 n.a. n.a.

2,537.40 65.97 748.64 256.52 1,339.23 393.06 946.16 – –224.94 18.18 45.97 25.82 10.64 37.27 -26.63 – –

22.59 1.83 4.62 2.59 1.07 3.74 -2.67 – –PV stands for a present value discounted by 10% p.a. Source: Study TeamAnnu stands for an annualized value of respective present value.

TotalPV

Annu

DSCRDepreciation PBT Tax PATRevenue Interest LLCRO&M CostYear

3. FINANCIAL SENSITIVITY

A financial sensitivity was re-demonstrated to examine the extent to which the financial indicators change for different values of the major variables. This supplemental evaluation is compared to the original six cases (Base Case, + CDM, – 10% Tariff, – 10% Annual Energy, + 10% CAPEX & OPEX, and + 1 year delay of commissioning) as given in Table 3-1.


7

Table 3-1 Financial Indicators Analysis Cases FIRR US$M ROI US$M Source

0. Base Case 10.7% 10.6 24.5% 75.3 the base case Main Report

1. +CDM 11.2% 17.6 25.5% 82.4 CDM benefit added to the base case Main Report

2. –10% Tariff 9.5% -6.3 22.0% 58.5 electricity tariff 10% less Main Report

3. –10% Energy 9.5% -6.3 22.0% 58.5 less annual energy by 10% Main Report

4. +10% CAPEX 9.7% -5.0 22.5% 66.5 greater cost by 10% Main Report

5. COD Delayed by 1 yr 9.9% -1.0 21.4% 65.1 commissioning delayed by 1 year Main Report

6. Supplemental 11.1% 17.6 23.9% 82.4 Actual Tariff applied to Base Case Supplemental

Columns with US$M correspond to respective net present values Source: Study Team

Part 18 Supplemental Financial Evaluation for Masang-2 HEPP

Supplemental Financial Evaluation for Masang-2

1

SUPPLEMENTAL FINANCIAL EVALUATION FOR MASANG-2

1. INTRODUCTION

This paper is a supplement to the Main Report on the Project for the Master Plan Study of Hydropower Development in Indonesia, hereinafter referred to as the Main Report. It is to provide an additional financial evaluation in the Masang-2 Hydropower Project, which focuses the pseudo electricity selling price governing the project’s revenue. This paper applies the actual electricity sales by PLN to the project revenue, while the Main Report used a shadow electricity tariff that includes the Government subsidy granted to PLN.

2. FINANCIAL EVALUATION

2.1 METHODOLOGY, ASSUMPTIONS, AND FINANCIAL COST

The methodology used, the assumptions set, and financial cost assumed are exactly same as those in the Main Report. The financial capital expenditure (CAPEX) applied for the Masang-2 Hydropower Project is US$193 million, excluding costs required for the feasibility study.

2.2 FINANCIAL BENEFIT

2.2.1 Electricity Tariff

The Main Report has chosen a shadow tariff US¢10.63/kWh (US¢7.48/kWh of the selling price and US¢3.15/kWh of the Government subsidy) as of 2010, while this paper applies the actual electricity selling price US¢7.48/kWh as of 2010 without the Government subsidy, as compared in Table 2-1.

Table 2-1 Electricity Sales and Subsidy

Year Electricity Sales Subsidy Sum Electricity

(GWh) Tariff P Tariff S

Rp T US$M Rp T US$M US$M US¢/kWh US¢/kWh2002 39,018 4,335 4,739 527 4,862 108,360 4.001 4.4872003 49,810 5,534 4,097 455 5,990 113,020 4.897 5.3002004 58,232 6,470 3,470 386 6,856 120,244 5.381 5.7022005 63,246 7,027 12,511 1,390 8,417 127,370 5.517 6.6092006 70,735 7,859 32,909 3,657 11,516 133,108 5.905 8.6522007 76,286 8,476 36,605 4,067 12,543 142,441 5.951 8.8062008 84,250 9,361 78,577 8,731 18,092 149,437 6.264 12.1072009 90,172 10,019 53,720 5,969 15,988 156,797 6.390 10.1972010* N/A N/A 55,100 6,122 N/A 194,459 7.479 10.6272011* N/A N/A 41,000 4,556 N/A 201,977 7.689 9.945 Electricity = Electricity sold by PLN Tariff P = average electricity charge without subsidy Tariff S = electricity charge with subsidy * Estimations for “Electricity Sold” and “Tariff P” based on the past trends in 2005 to 2009. Rp.9,000/US$ is used for Rupiah to US$ conversion. Source: Study Team based on PLN Statistics 2009 and MOF data

The electricity tariff is assumed to be escalated as same as it was done in the past. The trend line of the past electricity tariff suggests that the electricity tariff would be increased by US¢0.2105 every year as seen in Figure 2-1. The electricity tariff would be then 9.16US¢/kWh in 2018, the first operating year.


2

y = 0.2105x + 5.3739

0

2

4

6

8

10

2005 2006 2007 2008 2009 2010 2011 2012 2013

Tarif

f (U

S¢/

kWh)

Year

Source: Study Team

Figure 2-1 Electricity Tariff Projection

2.2.2 Project Revenue

The project revenue is of the electricity tariff multiplied by the expected electricity sold. The first operating year revenue as of 2018 is then;

US$19.15 mill./year = US$0. 0916/kWh x 209 GWh/year

Where 209 GWh/year is the net annual energy.

Benefit from Certified Emission Reduction (CER) is exactly same as discussed in the Main Report.

2.3 FINANCIAL ANALYSIS

2.3.1 Interest Free Cash Flow

An interest free cash flow here evaluates the project’s profitability without financing charges but with income tax. The financial stream is tabulated in Table 2-2. The key indicators in present worth are:

NPVP = -US$40.7 million FIRR = 6.8%

B/C = 0.77

The FIRR computed is much greater than 2.0% of the hurdle rate, and therefore PLN as the project-operating entity will be able to make profit from the project with high probability. However, its NPVP shows a negative value (as FIRR is less than 10% of discount rate) and therefore profit expected from the project should be evaluated marginal.


3

Table 2-2 Interest Free Financial Stream US$ million GWh

CAPEX O&M Tax Sub-total Sales CER Sub-total2011 -6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 02012 -5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 02013 -4 2.32 0.00 0.00 2.32 0.00 0.00 0.00 -2.32 02014 -3 15.83 0.00 0.00 15.83 0.00 0.00 0.00 -15.83 02015 -2 53.59 0.00 0.00 53.59 0.00 0.00 0.00 -53.59 02016 -1 76.04 0.00 0.00 76.04 0.00 0.00 0.00 -76.04 02017 0 45.12 0.00 0.00 45.12 0.00 0.00 0.00 -45.12 02018 1 0.00 4.49 2.19 6.68 19.15 0.97 20.12 13.44 2092019 2 0.00 4.64 2.26 6.90 19.59 0.97 20.56 13.66 2092020 3 0.00 4.79 2.33 7.12 20.03 0.97 21.00 13.87 2092021 4 0.00 4.95 2.40 7.35 20.47 0.97 21.44 14.08 2092022 5 0.00 5.12 2.47 7.59 20.91 0.97 21.88 14.29 2092023 6 0.00 5.29 2.54 7.83 21.35 0.97 22.32 14.49 2092024 7 0.00 5.47 2.60 8.07 21.79 0.97 22.76 14.68 2092025 8 0.00 5.66 2.69 8.35 22.23 0.97 23.20 14.84 2092026 9 0.00 5.86 2.78 8.64 22.67 0.97 23.64 15.00 2092027 10 0.00 6.06 2.87 8.93 23.11 0.97 24.08 15.15 2092028 11 0.00 6.27 2.96 9.22 23.55 0.97 24.52 15.29 2092029 12 0.00 6.49 3.04 9.53 23.99 0.97 24.96 15.43 2092030 13 0.00 6.72 3.12 9.84 24.43 0.97 25.40 15.56 2092031 14 0.00 6.95 3.20 10.15 24.87 0.97 25.84 15.68 2092032 15 0.00 7.20 3.28 10.48 25.31 0.97 26.28 15.80 2092033 16 0.00 7.46 3.35 10.81 25.75 0.97 26.72 15.91 2092034 17 0.00 7.73 3.42 11.15 26.19 0.97 27.16 16.01 2092035 18 0.00 8.01 3.49 11.50 26.63 0.97 27.60 16.10 2092036 19 0.00 8.30 3.56 11.86 27.07 0.97 28.04 16.18 2092037 20 0.00 8.60 3.62 12.22 27.51 0.97 28.48 16.25 2092038 21 0.00 8.92 3.68 12.60 27.95 0.97 28.92 16.32 2092039 22 0.00 9.25 3.73 12.98 28.38 0.97 29.36 16.37 2092040 23 0.00 9.59 3.79 13.38 28.82 0.97 29.80 16.42 2092041 24 0.00 9.95 3.84 13.79 29.26 0.97 30.24 16.45 2092042 25 0.00 10.33 3.88 14.21 29.70 0.97 30.67 16.47 2092043 26 0.00 10.72 3.92 14.64 30.14 0.97 31.11 16.48 2092044 27 0.00 11.12 3.96 15.08 30.58 0.97 31.55 16.47 2092045 28 0.00 11.55 3.99 15.54 31.02 0.97 31.99 16.46 2092046 29 0.00 11.99 4.02 16.01 31.46 0.97 32.43 16.43 2092047 30 0.00 12.45 4.04 16.49 31.90 0.97 32.87 16.38 2092048 31 0.00 12.02 0.00 12.02 0.00 0.00 0.00 -12.02 02049 32 0.00 13.44 3.76 17.19 32.78 0.97 33.75 16.56 2092050 33 0.00 13.96 3.73 17.70 33.22 0.97 34.19 16.50 2092051 34 0.00 14.51 3.71 18.22 33.66 0.97 34.63 16.41 2092052 35 0.00 15.09 3.67 18.76 34.10 0.97 35.07 16.31 2092053 36 0.00 15.68 3.63 19.32 34.54 0.97 35.51 16.20 2092054 37 0.00 16.31 3.59 19.90 34.98 0.97 35.95 16.06 2092055 38 0.00 16.96 3.53 20.50 35.42 0.97 36.39 15.90 2092056 39 0.00 17.64 3.47 21.12 35.86 0.97 36.83 15.72 2092057 40 0.00 18.36 3.41 21.76 36.30 0.97 37.27 15.51 2092058 41 0.00 19.10 3.33 22.43 36.74 0.97 37.71 15.28 2092059 42 0.00 19.88 3.24 23.13 37.18 0.97 38.15 15.03 2092060 43 0.00 20.69 3.15 23.85 37.62 0.97 38.59 14.75 2092061 44 0.00 21.55 3.05 24.59 38.06 0.97 39.03 14.44 2092062 45 0.00 22.43 2.94 25.37 38.50 0.97 39.47 14.10 2092063 46 0.00 23.36 2.81 26.18 38.94 0.97 39.91 13.74 2092064 47 0.00 24.34 2.68 27.02 39.38 0.97 40.35 13.34 2092065 48 0.00 25.35 2.54 27.89 39.82 0.97 40.79 12.90 2092066 49 0.00 26.42 2.38 28.80 40.26 0.97 41.23 12.44 2092067 50 -42.95 27.53 2.21 -13.21 40.70 0.97 41.67 54.89 209

149.95 616.57 157.83 924.34 1463.88 47.55 1511.43 587.09 10,239122.89 37.26 15.68 175.83 129.77 5.40 135.17 -40.66 –

12.34 3.74 1.58 17.66 13.03 0.54 13.58 -4.08 –NPVP = -40.66 FIRR = 6.84% B/C = 0.77 Cost =


TotalPV

Annu

YearCost Benefit Net

Benefit

Source: Study Team

EnergySupply

US¢8.5/kWh

2.3.2 Return on Investment

Assuming the loan conditions exactly same as the Main Report in Table 2-3, the return on investment was computed as given in Table 2-4 by using a DCF model. The net present value and rate of return are:


4

NPVI = US$18.9 million ROI = 14.4%

Table 2-3 Loan Conditions Assumed for Financial Cash Flow

Lender Interest Rate (p.a)

Front-end fee

Commitment fee (p.a)

Graceperiod

Repay period

Loan share

Bilateral Institution 1.90% 0.00% 0.75% 7 years 25 years 75%

Notes 1. The front-end fee will be charged only at the time of loan agreement. The commitment fee is charged against unused loan amount and will decrease gradually and end at null when the loan amount is fully disbursed.

2. Interest rate is assumed constant and being composed of 1.4% p.a. of JICA’s standard rate for medium income countries plus 0.5% p.a. of onlending spread by MOF.

3. Grace period includes 4 years of construction. 4. No insurance is counted. Source: Study Team

The project can be evaluated financially feasible from a long term view. A breakeven of the investment will be 5 years after commissioning. Because no revenue is expected in the replacement year scheduled 30 years after commissioning, however, the project will not be able to fulfill the debt service obligation in the same year. As an enough return is expected, the project can overcome the debt service issue. For example, if 7% of the annual net profit is deposited every year into a saving account, the project will easily be able to have enough cash when no revenue is expected due to machine replacement.

-40

-30

-20

-10

0

10

20

30

40

50

2018

2021

2024

2027

2030

2033

2036

2039

2042

2045

2048

2051

2054

2057

2060

2063

2066

Reve

nue a

nd C

ost (

US$

mill

.)

Years

Tax

Interest

Principal

O&M

Revenue

PAT

Source: Study Team

Figure 2-2 Cash Inflow and Outflow

Assuming the aforementioned explicit savings for the replacement cost, DSCR and LLCR can be raised as:

Minimum DSCR = 1.4 > 1.0 Minimum LLCR = 1.6 > 1.0

Now, all of the indicators show enough numbers and therefore one can evaluate the hydropower project in question is financially viable. The profit and loss calculations are given in Table 2-5.


5

Table 2-4 Financial Cash Flow for ROI US$ million

Cash GenerationSales Residual O&M Interest Repay Tax Net Sum

2011 -6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.002012 -5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.002013 -4 2.09 0.00 0.00 0.00 0.01 0.00 0.00 -2.10 -2.102014 -3 14.28 0.00 0.00 0.00 0.05 0.00 0.00 -14.33 -16.432015 -2 27.12 0.00 0.00 0.00 0.74 0.00 0.00 -27.86 -44.292016 -1 0.00 0.00 0.00 0.00 2.55 0.00 0.00 -2.55 -46.842017 0 0.00 0.00 0.00 0.00 3.20 0.00 0.00 -3.20 -50.032018 1 0.00 19.15 0.00 4.49 2.85 0.00 2.19 10.59 -39.452019 2 0.00 19.59 0.00 4.64 2.85 0.00 2.26 10.81 -28.642020 3 0.00 20.03 0.00 4.79 2.85 0.00 2.33 11.02 -17.622021 4 0.00 20.47 0.00 4.95 2.85 0.00 2.40 11.23 -6.392022 5 0.00 20.91 0.00 5.12 2.85 0.00 2.47 11.44 5.052023 6 0.00 21.35 0.00 5.29 2.85 0.00 2.54 11.64 16.692024 7 0.00 21.79 0.00 5.47 2.85 0.00 2.60 11.83 28.522025 8 0.00 22.23 0.00 5.66 2.74 6.00 2.69 6.10 34.622026 9 0.00 22.67 0.00 5.86 2.62 6.00 2.78 6.37 40.992027 10 0.00 23.11 0.00 6.06 2.51 6.00 2.87 6.64 47.632028 11 0.00 23.55 0.00 6.27 2.40 6.00 2.96 6.89 54.522029 12 0.00 23.99 0.00 6.49 2.28 6.00 3.04 7.14 61.662030 13 0.00 24.43 0.00 6.72 2.17 6.00 3.12 7.39 69.052031 14 0.00 24.87 0.00 6.95 2.05 6.00 3.20 7.62 76.682032 15 0.00 25.31 0.00 7.20 1.94 6.00 3.28 7.85 84.532033 16 0.00 25.75 0.00 7.46 1.83 6.00 3.35 8.08 92.612034 17 0.00 26.19 0.00 7.73 1.71 6.00 3.42 8.29 100.902035 18 0.00 26.63 0.00 8.01 1.60 6.00 3.49 8.50 109.392036 19 0.00 27.07 0.00 8.30 1.48 6.00 3.56 8.69 118.092037 20 0.00 27.51 0.00 8.60 1.37 6.00 3.62 8.88 126.972038 21 0.00 27.95 0.00 8.92 1.25 6.00 3.68 9.06 136.032039 22 0.00 28.38 0.00 9.25 1.14 6.00 3.73 9.23 145.262040 23 0.00 28.82 0.00 9.59 1.03 6.00 3.79 9.38 154.642041 24 0.00 29.26 0.00 9.95 0.91 6.00 3.84 9.53 164.172042 25 0.00 29.70 0.00 10.33 0.80 6.00 3.88 9.67 173.842043 26 0.00 30.14 0.00 10.72 0.68 6.00 3.92 9.79 183.632044 27 0.00 30.58 0.00 11.12 0.57 6.00 3.96 9.90 193.532045 28 0.00 31.02 0.00 11.55 0.46 6.00 3.99 10.00 203.522046 29 0.00 31.46 0.00 11.99 0.34 6.00 4.02 10.08 213.602047 30 0.00 31.90 0.00 12.45 0.23 6.00 4.04 10.15 223.752048 31 0.00 0.00 0.00 12.02 0.11 6.00 0.00 -18.14 205.622049 32 0.00 32.78 0.00 13.44 0.00 6.00 3.76 10.56 216.172050 33 0.00 33.22 0.00 13.96 0.00 0.00 3.73 16.50 232.672051 34 0.00 33.66 0.00 14.51 0.00 0.00 3.71 16.41 249.082052 35 0.00 34.10 0.00 15.09 0.00 0.00 3.67 16.31 265.402053 36 0.00 34.54 0.00 15.68 0.00 0.00 3.63 16.20 281.592054 37 0.00 34.98 0.00 16.31 0.00 0.00 3.59 16.06 297.652055 38 0.00 35.42 0.00 16.96 0.00 0.00 3.53 15.90 313.552056 39 0.00 35.86 0.00 17.64 0.00 0.00 3.47 15.72 329.262057 40 0.00 36.30 0.00 18.36 0.00 0.00 3.41 15.51 344.772058 41 0.00 36.74 0.00 19.10 0.00 0.00 3.33 15.28 360.052059 42 0.00 37.18 0.00 19.88 0.00 0.00 3.24 15.03 375.082060 43 0.00 37.62 0.00 20.69 0.00 0.00 3.15 14.75 389.832061 44 0.00 38.06 0.00 21.55 0.00 0.00 3.05 14.44 404.272062 45 0.00 38.50 0.00 22.43 0.00 0.00 2.94 14.10 418.372063 46 0.00 38.94 0.00 23.36 0.00 0.00 2.81 13.74 432.112064 47 0.00 39.38 0.00 24.34 0.00 0.00 2.68 13.34 445.442065 48 0.00 39.82 0.00 25.35 0.00 0.00 2.54 12.90 458.352066 49 0.00 40.26 0.00 26.42 0.00 0.00 2.38 12.44 470.782067 50 0.00 40.70 42.95 27.53 0.00 0.00 2.21 54.89 525.67

43.50 1,463.88 42.95 616.57 60.72 150.10 157.83 525.67 –30.99 129.77 0.21 37.26 16.73 15.79 15.68 18.94 –

3.11 13.03 0.02 3.74 1.68 1.59 1.58 1.90 –NPVI = 18.94 ROI = 14.39% Source: Study Team


PVAnnu

BenefitInvestYear

Total


6

Table 2-5 Profit and Loss US$ million

2011 -6 0.00 0.00 0.00 0.00 0.00 0.00 0.002012 -5 0.00 0.00 0.00 0.00 0.00 0.00 0.002013 -4 0.00 0.01 0.00 0.00 -2.33 0.00 -2.332014 -3 0.00 0.05 0.00 0.00 -15.88 0.00 -15.882015 -2 0.00 0.74 0.00 0.00 -54.33 0.00 -54.332016 -1 0.00 2.55 0.00 0.00 -78.59 0.00 -78.592017 0 0.00 3.20 0.00 0.00 -48.32 0.00 -48.322018 1 19.15 2.85 4.49 4.03 8.74 2.19 6.56 4.17 1.812019 2 19.59 2.85 4.64 4.03 9.04 2.26 6.78 4.52 1.782020 3 20.03 2.85 4.79 4.03 9.32 2.33 6.99 4.88 1.762021 4 20.47 2.85 4.95 4.03 9.60 2.40 7.20 5.24 1.732022 5 20.91 2.85 5.12 4.03 9.88 2.47 7.41 5.60 1.702023 6 21.35 2.85 5.29 4.03 10.14 2.54 7.61 5.97 1.672024 7 21.79 2.85 5.47 4.03 10.40 2.60 7.80 6.34 1.642025 8 22.23 2.74 5.66 4.03 10.77 2.69 8.08 2.22 1.612026 9 22.67 2.62 5.86 4.03 11.13 2.78 8.35 2.32 1.632027 10 23.11 2.51 6.06 4.03 11.48 2.87 8.61 2.42 1.662028 11 23.55 2.40 6.27 4.03 11.82 2.96 8.87 2.53 1.682029 12 23.99 2.28 6.49 4.03 12.16 3.04 9.12 2.64 1.712030 13 24.43 2.17 6.72 4.03 12.48 3.12 9.36 2.76 1.742031 14 24.87 2.05 6.95 4.03 12.80 3.20 9.60 2.88 1.772032 15 25.31 1.94 7.20 4.03 13.11 3.28 9.83 3.01 1.812033 16 25.75 1.83 7.46 4.03 13.40 3.35 10.05 3.14 1.852034 17 26.19 1.71 7.73 4.03 13.69 3.42 10.27 3.28 1.902035 18 26.63 1.60 8.01 4.03 13.96 3.49 10.47 3.42 1.952036 19 27.07 1.48 8.30 4.03 14.22 3.56 10.67 3.57 2.012037 20 27.51 1.37 8.60 4.03 14.47 3.62 10.86 3.72 2.082038 21 27.95 1.25 8.92 4.03 14.71 3.68 11.03 3.88 2.162039 22 28.38 1.14 9.25 4.03 14.94 3.73 11.20 4.04 2.252040 23 28.82 1.03 9.59 4.03 15.15 3.79 11.36 4.21 2.362041 24 29.26 0.91 9.95 4.03 15.34 3.84 11.51 4.38 2.502042 25 29.70 0.80 10.33 4.03 15.52 3.88 11.64 4.56 2.682043 26 30.14 0.68 10.72 4.03 15.68 3.92 11.76 4.75 2.902044 27 30.58 0.57 11.12 4.03 15.83 3.96 11.87 4.94 3.212045 28 31.02 0.46 11.55 4.03 15.96 3.99 11.97 5.14 3.632046 29 31.46 0.34 11.99 4.03 16.07 4.02 12.05 5.35 4.272047 30 31.90 0.23 12.45 4.03 16.16 4.04 12.12 5.56 5.332048 31 0.00 0.11 12.02 2.23 -14.36 0.00 -14.36 1.39 8.572049 32 32.78 0.00 13.44 5.30 15.02 3.76 11.27 2.50 16.072050 33 33.22 0.00 13.96 5.30 14.93 3.73 11.20 n.a. n.a.2051 34 33.66 0.00 14.51 5.30 14.83 3.71 11.12 n.a. n.a.2052 35 34.10 0.00 15.09 5.30 14.69 3.67 11.02 n.a. n.a.2053 36 34.54 0.00 15.68 5.30 14.53 3.63 10.90 n.a. n.a.2054 37 34.98 0.00 16.31 5.30 14.35 3.59 10.76 n.a. n.a.2055 38 35.42 0.00 16.96 5.30 14.14 3.53 10.60 n.a. n.a.2056 39 35.86 0.00 17.64 5.30 13.89 3.47 10.42 n.a. n.a.2057 40 36.30 0.00 18.36 5.30 13.62 3.41 10.22 n.a. n.a.2058 41 36.74 0.00 19.10 5.30 13.32 3.33 9.99 n.a. n.a.2059 42 37.18 0.00 19.88 5.30 12.98 3.24 9.73 n.a. n.a.2060 43 37.62 0.00 20.69 5.30 12.60 3.15 9.45 n.a. n.a.2061 44 38.06 0.00 21.55 5.30 12.19 3.05 9.14 n.a. n.a.2062 45 38.50 0.00 22.43 5.30 11.74 2.94 8.81 n.a. n.a.2063 46 38.94 0.00 23.36 5.30 11.25 2.81 8.44 n.a. n.a.2064 47 39.38 0.00 24.34 5.30 10.72 2.68 8.04 n.a. n.a.2065 48 39.82 0.00 25.35 5.30 10.14 2.54 7.61 n.a. n.a.2066 49 40.26 0.00 26.42 5.30 9.52 2.38 7.14 n.a. n.a.2067 50 40.70 0.00 27.53 5.30 8.85 2.21 6.64 n.a. n.a.

1,463.88 60.72 616.57 223.73 417.52 157.83 259.69 – –129.77 16.73 37.26 22.81 -64.72 15.68 -80.40 – –

13.03 1.68 3.74 2.29 -6.50 1.58 -8.08 – –PV stands for a present value discounted by 10% p.a. Source: Study TeamAnnu stands for an annualized value of respective present value.

TotalPV

Annu

DSCRDepreciation PBT Tax PATRevenue Interest LLCRO&M CostYear

3. FINANCIAL SENSITIVITY

A financial sensitivity was re-demonstrated to examine the extent to which the financial indicators change for different values of the major variables. This supplemental evaluation is compared to the original six cases (Base Case, + CDM, – 10% Tariff, – 10% Annual Energy, + 10% CAPEX & OPEX, and + 1 year delay of commissioning) as given in Table 3-1.


7

Table 3-1 Financial Indicators Analysis Cases FIRR US$M ROI US$M Source

0. Base Case 6.6% -40.5 15.0% 19.1 the base case Main Report

1. +CDM 7.0% -36.4 15.9% 23.2 CDM benefit added to the base case Main Report

2. –10% Tariff 5.6% -50.6 12.5% 9.0 electricity tariff 10% less Main Report

3. –10% Energy 5.6% -50.6 12.5% 9.0 less annual energy by 10% Main Report

4. +10% CAPEX 5.8% -54.5 12.8% 11.1 greater cost by 10% Main Report

5. COD Delayed by 1 yr 6.2% -47.0 13.4% 13.9 commissioning delayed by 1 year Main Report

6. Supplemental 6.8% -40.7 14.4% 18.9 Actual Tariff applied to Base Case Supplemental

Columns with US$M correspond to respective net present values Source: Study Team

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