Hydrological Analysis for Masang-2 HEPP

Part 16 Hydrological Analysis for Masang-2 HEPP

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 22 is summarized below. Unit: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 26.3 26.2 26.4 26.5 26.6 26.3 25.9 25.7 25.7 25.8 25.7 26. 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 JICA Project for the Master Plan Study of 16-1 August, 211

22 is summarized below. Unit: % Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 81.1 81.3 82.4 83. 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 1971-22 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 22 is summarized below. Unit: % Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 53.1 57.4 53.3 55.3 59.5 61.7 6.9 55.4 42.9 41.7 4.4 5.7 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 4.4 % 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 22 is summarized below. Unit: m/sec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 1.3 1.3 1.3 1.1 1..9 1.1 1. 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.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 199 to 22 are around.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. JICA Project for the Master Plan Study of 16-2 August, 211

Station Name: Lubuk Sukaping (1979-1985) Unit: mm/day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 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 Station Name: Tanjung Pati (1975-1985) Unit: mm/day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 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 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. Rainfall(mm) 6 5 4 3 2 1 Maninjau: 3,199 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec JICA Project for the Master Plan Study of 16-3 August, 211

Rainfall(mm) 6 5 4 3 2 1 Limau Purut: 3,491 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Rainfall(mm) Padang Panjang: 3,76 mm (1969-22) 6 5 4 3 2 1 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Rainfall(mm) Rainfall(mm) 6 5 4 3 2 1 6 5 4 3 2 1 Bukit Tinggi: 2,21 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Baso: 2,12 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec JICA Project for the Master Plan Study of 16-4 August, 211

Rainfall(mm) Padang Mangatas: 2,45 mm (1969-1993) 6 5 4 3 2 1 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Rainfall(mm) Rainfall(mm) Rainfall(mm) 6 5 4 3 2 1 6 5 4 3 2 1 6 5 4 3 2 1 Payakumbuh: 2,181 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Koto Tinggi: 2,638 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Suliki: 2,44 mm (1969-27) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec JICA Project for the Master Plan Study of 16-5 August, 211

Rainfall(mm) Rainfall(mm) Rainfall(mm) Rainfall(mm) 6 5 4 3 2 1 6 5 4 3 2 1 6 5 4 3 2 1 6 5 4 3 2 1 Kota Baharu: 2,828 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Bonjol: 4,613 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jambak: 3,797 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Lubuk Sikaping: 3,76 mm (1969-1993) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec As seen above, the annual mean rainfall at these stations ranges from 2, mm to 4,6 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 JICA Project for the Master Plan Study of 16-6 August, 211

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 5 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 km 2 in the records from 1975 to 1992, and as 436.4 km 2 in the records from 1993to 28. On this study, the catchment area of the station is measured as 475km 2 based on 1:5, scale map. Besides, the catchment area of Masang-2 HEPP intake weir site is measured as 443km 2. 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 28 except in 1988, 1989, 1994, 22, 23 and 24. The monthly mean runoff at the Sipisang AWLR station is presented in Table 2. 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 1975-28 is summarized below. Station Name: Sipisang (1975-28) Unit: m3/s Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 22.4 2. 21.6 23.8 22.5 18.7 16.8 18.1 2.6 21.4 27.7 29.2 21.9 As seen, the annual mean runoff at the Sipisang AWLR station is 21.9m 3 /s or 1,455mm in JICA Project for the Master Plan Study of 16-7 August, 211

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 2 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 28 except in 1988, 1989, 1994, 22, 23 and 24. 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. JICA Project for the Master Plan Study of 16-8 August, 211

(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. P CX = PX ( M C / M a ) where, P CX : Corrected rainfall at any time period at station x (mm) P X : Original recorded rainfall at any time period at station x (mm) M C : Corrected slope of the double-mass curve M : Original slope of the double-mass curve a JICA Project for the Master Plan Study of 16-9 August, 211

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.67.23.1 Case2 (1987 to 1993) Koto Tinggi Suliki Jambak.74.21.5 The estimated monthly basin mean rainfall at the Sipisang AWLR station is presented in Table 22. The estimated annual basin mean rainfall is 2,57mm. (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 km 2 for the same period as above. The established relationship between annual basin mean rainfall and annual runoff depth at JICA Project for the Master Plan Study of 16-1 August, 211

the Sipisang station is as follows. Besides, the relationship is plotted in Figure 19. Year Annual Rainfall (mm) Annual Runoff Depth Annual Rainfall Loss Runoff Coefficient 1976 2,27 1,375 832.62 1982 2,43 1,253 1,176.52 1983 2,314 1,233 1,81.53 1984 3,339 1,318 2,22.39 1985 2,615 1,449 1,165.55 1986 3,29 1,45 1,579.48 1991 3,3 1,326 1,74.44 1993 3,27 2,11 925.69 Average 2,749 1,438 1,311.53 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 2. It is therefore found that the annual rainfall loss normally falls in a range of 7 to 1,5 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 8mm to 2,mm. 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 1,2 to 1,5 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. JICA Project for the Master Plan Study of 16-11 August, 211

Year Annual Rainfall (mm) Annual Runoff Depth Annual Rainfall Loss Runoff Coefficient 1976 2,626 1,375 1,251.52 1982 2,43 1,253 1,176.52 1983 2,314 1,233 1,81.53 1984 2,568 1,318 1,251.51 1985 2,615 1,449 1,165.55 1986 3,29 1,45 1,579.48 1991 2,577 1,326 1,251.51 1993 - - - - Average 2,594 1,343 1,251.52 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. Accumulated Runoff Depth (mm) 1, 5, 1982 1983 1984 1985 1986 1991-1976 - 5, 1, 15, 2, Accumulated Basin Mean Rainfall (mm) 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. JICA Project for the Master Plan Study of 16-12 August, 211

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. Q = α H 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. T 2 = TC( XP / PS XS / SS) where, T 2 : Transfer of moisture between primary and secondary zones (if positive, transfer occurs from primary to secondary, and vice versa) TC : Constant JICA Project for the Master Plan Study of 16-13 August, 211

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. T1 = TB(1 XP / PS) where, T 1 : 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 4 Calculation Time Interval 1 month Calculation Period 1982 to 1986 Observed Runoff at Sipisang Station 1982 to 1986 Basin Mean Rainfall at Sipisang Station 1982 to 1986 Monthly Average Evaporation at Lubuk Sikaping 1979 to 1985 The pan evaporation record at the Lubuk Sikaping station is applied. The pan coefficient of.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/day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean 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 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. JICA Project for the Master Plan Study of 16-14 August, 211

Hole Coefficient Height of Hole (mm) β α1 α2 H1 H2 Tank-1.3.35.35 15. 3. Tank-2.5.7. 5.. Tank-3.1.3. 2.. Tank-4.1.6... 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 4 % in probability varies between.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. Annual Annual Runoff Depth Annual Rainfall Loss Rainfall (mm) (mm) Runoff Coefficient Year (mm) Observed Simulated Observed Simulated Observed Simulated 1982 2,43 1,254 1,23 1,177 1,227.52.5 1983 2,314 1,233 1,143 1,81 1,171.53.49 1984 2,635 1,314 1,241 1,321 1,395.5.47 1985 2,615 1,449 1,4 1,166 1,215.55.54 1986 3,29 1,45 1,697 1,579 1,332.48.56 Average 2,65 1,34 1,337 1,265 1,268.52.51 As seen above, the average runoff coefficient and rainfall loss of the simulated runoff are derived to be.51 and 1,268 mm, respectively. On the other hand, hydrological indices of the observed runoff at the Sipisang station are.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. JICA Project for the Master Plan Study of 16-15 August, 211

Year Annual Rainfall (mm) Annual Runoff Depth (mm) Annual Rainfall Loss (mm) Runoff Coefficient Observed Simulated Observed Simulated Observed Simulated 1973 2,213-1,188-1,25 -.54 1974 2,622-1,255-1,367 -.48 1975 1,882-99 - 893 -.53 1976 2,28 1,371 848 836 1,36.62.38 1977 2,215-1,1-1,25 -.46 1978 2,23-1,71-1,132 -.49 1979 2,61-866 - 1,195 -.42 198 2,252-919 - 1,333 -.41 1981 2,797-1,43-1,395 -.5 1982 2,43 1,254 1,377 1,177 1,53.52.57 1983 2,314 1,233 1,159 1,81 1,155.53.5 1984 2,635 1,314 1,245 1,321 1,39.5.47 1985 2,615 1,449 1,41 1,166 1,214.55.54 1986 3,29 1,45 1,697 1,579 1,332.48.56 1987 2,674-1,41-1,264 -.53 1988 2,231-1,292-939 -.58 1989 2,122-963 - 1,159 -.45 199 2,516-1,184-1,333 -.47 1991 3,3 1,326 1,538 1,74 1,492.44.51 1992 2,874-1,821-1,53 -.63 1993 3,27-1,646-1,381 -.54 Average 2,474-1,251-1,222 -.5 As seen in the table, the average runoff coefficient and rainfall loss of the simulated runoff are derived to be.5 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. JICA Project for the Master Plan Study of 16-16 August, 211

Time Interval Daily Observed Daily Runoff 1976, 1982 to 1986, 1991 Simulated Monthly Runoff 1973 to 1975, 1977 to 1981, 1987 to 199, 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. Q D = QW ( AD / AW ) where, Q D : Runoff at Masang-2 intake weir site (m 3 /sec) Q W : Runoff at Sipisang AWLR station (m 3 /sec) A D : Catchment area at Masang-2 intake weir site (=443km 2 ) A : Catchment area at Sipisang AWLR station (=475km 2 ) W (9) Water Level Observation and Discharge Measurement The field investigation of 3 month water level observation and 3 times discharge measurement was carried out from 21 October 6 th to 211 January 7 th 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.75m and the average runoff is 23.85 m 3 /s calculated with H-Q rating curve. The Equation of H-Q rating curve is given below. Q = 36.55 ( H +.6) 2 where, Q : Runoff (m 3 /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 JICA Project for the Master Plan Study of 16-17 August, 211

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, km 2. 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) JICA Project for the Master Plan Study of 16-18 August, 211

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 5 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 3. Among the storm rainfalls bigger than 5mm, 6-hour of rainfall duration covers 63% of all. Besides, 6-hour of rainfall duration covers 8% of all among the storm rainfalls bigger than 1mm. So, the design rainfall duration time is estimated as 6-hour, which represents the characteristics of the storm rainfalls in Masang River basin. 4 of selected 63-storm rainfall have smaller duration time than 6-hours. The average of the 4 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) 1 2 3 4 5 6 Cumulative Rainfall Depth % 47% 78% 87% 95% 99% 1% Incremental Rainfall Depth % 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. P b n = P exp[ ka ] where, P b : Average rainfall depth over an area A (mm) P : Maximum point rainfall at the storm center (mm) A : Area in question (km 2 ) k, n : 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 P is practically impossible, because it is very unlikely that the rain storm center JICA Project for the Master Plan Study of 16-19 August, 211

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. P b = f a P where, P b : Basin mean rainfall (mm) P : Point rainfall (mm) f : Area reduction factor a If the Horton s equation is applied, the area reduction factor under the given rainfall duration is given by the following equation. f a = exp[ ka n ] 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.63 under the catchment area of 443 km 2 for the Masang-2 intake weir site by applying the Horton s equation assuming that constants of k and n are.1 and.25, respectively. These constants have been widely and empirically applied in tropical rain forest area. A 443 (km2) k.1 n.25 fa.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 Area Reduction (km2) Factor Besai HEPP (D/D in 199) 415.5 Malea HEPP (F/S in 1984) 1,463.45 Tampur-1 HEPP (F/S in 1984) 2,.4 Musi HEPP (F/S in 1984) 586.5 Cibuni-3 (F/S in 1984) 1,.41 Masang-3 HEPP (Pre F/S in 1999) 993.5 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 JICA Project for the Master Plan Study of 16-2 August, 211

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.5 to.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.4 to.5. In due consideration above, the design area reduction factor is conservatively determined to be.5. 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. Return Period Probable Point Rainfall (mm) (years) Gumbel LN Average 4 263 319 291 2 242 281 261 15 233 266 249 1 22 245 233 8 213 235 224 5 199 213 26 3 183 19 186 2 17 173 171 1 148 145 146 5 125 119 122 3 16 1 13 2 9 85 87 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. JICA Project for the Master Plan Study of 16-21 August, 211

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. X = X + K S m n m n where, X m : Extreme value of 24-hour rainfall (PMP) (mm) X n : Adjusted mean annual maximum rainfall (mm) K m : Statistical coefficient S : Adjusted standard deviation of a series of annual maximum rainfall n 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 K m 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 (X n ) and its standard deviation (S n ) are calculated to be 96.1 mm and 47.1 mm, respectively. Concurrently with the above, X n-m and S n-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 JICA Project for the Master Plan Study of 16-22 August, 211

parameters are used for several adjustment necessary computing X n and S n. Adjustment of X n and S n for Maximum Observed Event The adjustment factors of X n (f x1 ) and S n (f s1 ) 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 X n, X n-m, S n and S n-m, adjustment factors are obtained 97 % for f x1 and 89 % for f s1, respectively. Adjustment of X n and S n for Sample Size The adjustment factors of X n (f x2 ) and S n (f s2 ) for the length of record shall be obtained from the adjustment curves as presented in Figure 36. The obtained factors of f x2 and f s2 are 1.5 % and 11.6 %, respectively. Statistical Coefficient K m The statistical coefficient K m shall be obtained from the empirical K m curves as presented in Figure 37. Applying the mean annual maximum rainfall at the Payakumbuh station (X n ) 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 (f o ). 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 f o value is obtained to be 113 %. Computation of PMP at the Payakumbuh Station The adjustment mean annual maximum rainfall (X n ) is finally given as follows. X X n = f X 1 f X 2 n In addition, the adjusted standard deviation of a series of annual maximum rainfall (S n ) is given as follows. S S n = f S1 fs 2 n The unadjusted point PMP (X m ) is computed as follows. JICA Project for the Master Plan Study of 16-23 August, 211

X = X + K S m n m n Finally, the point PMP is adjusted using the adjustment factor f o as follows. PMP = f O X m 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.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. Return Period (years) Probable Rainfall (mm) PMP 426 4 146 2 131 15 125 1 117 8 112 5 13 3 93 2 86 1 73 5 61 3 52 2 44 (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. JICA Project for the Master Plan Study of 16-24 August, 211

q =.28AQ / p t p where, q p : Peak discharge (m 3 /sec) A : Basin area (km 2 ) Q : Total volume of the unit hydrograph (=1mm) t p : Time to peak (hours) SCS has determined that the time to peak ( t p ) and rainfall duration ( D ) are related to time of concentration ( t c ) as follows. t = p 2 tc /3 D =. 133t c 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. t c.77.385 = 3.97 L S where, t c : 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 ( t c ) was found to be about 6.2 hours. With a catchment area ( A ) of 443 km 2, the peak flow ( q ) is found to be 22.3 m 3 /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 4. A 443 km 2 Q 1 mm L 49.156 km t c 6.2 hours q p 22.3 m 3 /s/mm 4.1 hours t p p JICA Project for the Master Plan Study of 16-25 August, 211

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 (m 3 /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 3. 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. Q = ( 46.2832) C (.3861 A) p a a =.894(.3861 A).48 where, Q p : Peak discharge of probable flood (m 3 /sec) C : Creager s coefficient A : Catchment area (km 2 ) 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 92 4 1493 32 2 1341 28 15 128 27 1 1198 25 8 1152 24 5 161 22 3 959 2 2 883 19 1 756 16 5 634 13 3 537 11 2 456 1 Figure 43 and Figure 44 shows the relationship between probable flood peak discharges with return periods of 2, 2, 1, 2 years as well as PMF and catchment area for the Masang-2 JICA Project for the Master Plan Study of 16-26 August, 211

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 ( t c ) at the Masang-2 Regulating Pond is calculated as.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 1-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 km 2 L t c 1.3 km.17 hours The results of flood analysis are estimated as follows. Intake Pond T Q C Q (year) (m3/s) (m3/s) PMF 4344 92 49.1 4 1493 32 16.9 2 1341 28 15.2 15 128 27 14.5 1 1198 25 13.5 8 1152 24 13. 5 161 22 12. 3 959 2 1.8 2 883 19 1. 1 756 16 8.6 5 634 13 7.2 3 537 11 6.1 2 456 1 5.2 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 919.5km 2, illustrated in Figure 47. The results of flood analysis are estimated as follows. JICA Project for the Master Plan Study of 16-27 August, 211

Intake PH T Q C Q (year) (m3/s) (m3/s) PMF 4344 92 6281.3 4 1493 32 2158.8 2 1341 28 1939.1 15 128 27 185.9 1 1198 25 1732.3 8 1152 24 1665.8 5 161 22 1534.2 3 959 2 1386.7 2 883 19 1276.8 1 756 16 193.2 5 634 13 916.8 3 537 11 776.5 2 456 1 659.4 (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 3 times discharge measurement was carried out from 21 October 6 th to 211 January 7 th by the sub-contractor. Consequently, the maximum water level is 2.1m and the maximum runoff is 156.61 m 3 /s calculated with H-Q rating curve in extrapolation. The Equation of H-Q rating curve is given below. Q = 36.55 ( H +.6) 2 where, Q : Runoff (m 3 /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 JICA Project for the Master Plan Study of 16-28 August, 211

development projects in Sumatra are collected for comparison purposes. (2) Suspended Load Sampling A total of thirty (3) 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. Q =. 864 C S Q W where, Q S : Suspended load (ton/day) C : Total suspended sediment concentration (mg/l) Q : Flow discharge (m 3 /s) W 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. S 1.7812 5.4615 QW Q = 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 443km 2. 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. γ = ( 1 V ) γ where, γ : Density of sediment (ton/m 3 ) JICA Project for the Master Plan Study of 16-29 August, 211

V : Void ratio of sediment γ : Unit weight of sediment (=2.65ton/m 3 ) Assuming a void ratio of 6 % in sedimentation, the density of sediment is found to be 1.6 ton/m 3. Hence, the annual suspended load sediment is estimated at 348,82 m 3. 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 1 to 3 % of the total suspended load. The rate of bed load transport is estimated as 1% of the total suspended load, because 1% is usually applied in Indonesia. Consequently, the mean annual sediment inflow volume into the Masang-2 intake weir is estimated to be 383,72 m 3, which is equivalent to a denudation rate of.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 993.5 Bt. Tonggar W. Sumatra 32.45 Bt. Bayang-1 Pre-F/S W. Sumatra 84.7 Bt. Bayang-2 Pre-F/S W. Sumatra 36.7 Kotapanjang D/D Riau 3,337.5 Kampar River Basin F/S Jambi -.5 Upper Indragiri River Basin Jambi -.59 Middle Indragiri River Basin Jambi -.53 Merangin-2 D/D Jambi 1,39.34 Merangin-5 Pre-F/S Jambi 2,597.7 Lake Kerinci Jambi 1,53.72 Source: Masang-3 HEPP, 1999. As seen in the above table, the design denudation rates vary from.34 to.72 mm/year. The assumed denudation rate of.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.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. JICA Project for the Master Plan Study of 16-3 August, 211

Consequently, the design denudation rate of the Masang-2 intake weir is estimated as.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 221,5m 3 /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 16-31 August, 211

Table 1 Monthly Mean Air Temperature Station Name: Tabing-Padang Elevation: 2.m Unit: Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average 1971 26.1 26. 25.7 26.2 26.4 26.1 25.8 25.2 25.6 25.4 25. 25. 25.7 1972 25.6 25.7 25.9 26. 26.3 26.3 25.9 25.7 25.8 25.8 26. 26.2 25.9 1973 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. 1974 26.2 25.7 25.9 25.8 25.9 25.7 25.7 25.8 25.1 25.3 25.8 25.7 25.7 1975 25.5 25.6 25.9 26.2 26.3 25.7 25.1 25.5 25.4 25.4 25.3 25.3 25.6 1976 25.5 25.7 26.1 26.1 26.3 25.5 26.4 25.4 25.7 25.5 25.5 25.8 25.8 1977 26.1 25.7 26.6 26.7 26.4 26.3 25.9 25.8 26. 25.8 25.7 26.1 26.1 1978 26.1 26.2 26.5 26.5 26.7 26.2 25.8 26. 25.5 25.8 25.9 26.1 26.1 1979 26.6 26. 26.5 26.5 26.4 26.1 25.2 25.6 25.7 26.1 25.7 26.5 26.1 198 26.1 26.3 26.1 26. 26.8 26.4 25.8 25.5 25.7 25.6 25.9 25.8 26. 1981-26.1 27.1 26.5-26.5 25.7 25.7 25.5 25.5 25.5 26.1 26. 1982 25.6 25.7 25.9 26.3 26.3 26. 25.7 25.4 25.2-25.8 26.2 25.8 1983 26.9 26.9 27.5 26.9 26.6-26.2 26. 26. 25.9 26. 25.7 26.4 1984 25.6 25.7 25.9 25.9 26.3 26. 26. 25.4-25.6 25.5 25.4 25.8 1985 26. 25.8 26. 26.1 26.3 25.3 25.1 25.8 25.3 26. 25.6 26.3 25.8 1986 26.1 26.2 25.5 26.4 26.4 26.1 25.3 25.4 25.6 25.5 25.4 26.2 25.8 1987 26.8 26.3 26.5 25.6 26.6 26.8 25.9 26.1 26. 26. 25.9 26.3 26.2 1988 26.2 26. 26.3 26.8 26.7 26. 26. 25.4 25.4 26. 25.2 26.3 26. 1989 26.4 26.1-26.6 26.8-25.5-25.9 25.9 26. 26.3 26.2 199 26.1 26.9 27. 26.7 26.6 26.2-25.9 25.9 26. 26. 26.1 26.3 1991 26.3 26.5 26.8 26.3 26.8 26.6 26.3 25.9 26.1 25.8 25.4 26.1 26.2 1992 26.7 26.6 26.9 26.9 26.5 26.5 26. 26. 25.6 25.9 26. 26. 26.3 1993 26. 26.5 26. 26.5 26.4 26.8 26.2 25.8 25.8 26. 26. 26.2 26.2 1994 26.3 26.4 26.3 26.9 26.9 26.5 26. 25.5 24.9 25.4 26. 26.2 26.1 1995 26.7-27.7 27. 26.9 26.9 26.3-26.4 26.2-25.9 26.7 1996-26.4 - - - 26.5 25.8 25.8 - - 26.1 25.7 26. 1997 26.6-27.2 26.5-26.7-25.8 25.6 - - 26.2 26.4 1998 27.2 27.3 27.5 27.8 27.9 27. 26.8 26.1 26.1 26.3 26.1 26. 26.8 1999 26. 26.5 26.7 26.9 26.4 26.4 25.8 25.9 26. 25.9 25.9 26.2 26.2 2 26.6 26.7 26.1 26.5 26.7 26.6 26. 25.8 25.7 26.1 26.2 26.6 26.3 21 - - - - - - - - - - - - - 22 27.1 - - - - - - - - - - - 27.1 Min 25.5 25.6 25.5 25.6 25.9 25.3 25.1 25.2 24.9 25.3 25. 25. Max 27.2 27.3 27.7 27.8 27.9 27. 26.8 26.1 26.4 26.3 26.2 26.6 Ave 26.3 26.2 26.4 26.5 26.6 26.3 25.9 25.7 25.7 25.8 25.7 26. 26.1 Source: (1971-1989) Masang-3 HEPP Report, 1999 (199-22) BMKG JICA Project for the Master Plan Study of T-1 August, 211

Table 2 Monthly Mean Relative Humidity Station Name: Tabing-Padang Elevation: 2.m Unit: % Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average 1971 81. 8. 81. 82. 79. 79. 79. 85. 84. 84. 86. 86. 82.2 1972 82. 84. 82. 86. 86. 84. 84. 83. 85. 84. 85. 84. 84.1 1973 8. 81. 84. 85. 83. 82. 82. 82. 83. 84. 82. 83. 82.6 1974 81. 8. 82. 84. 83. 83. 81. 82. 86. 82. 83. 83. 82.5 1975 83. 84. 83. 84. 82. 82. 84. 82. 83. 83. 84. 83. 83.1 1976 81. 84. 82. 83. 82. 84. 84. 82. 84. 86. 85. 83. 83.3 1977 83. 8. 82. 84. 83. 8. 81. 81. 82. 86. 85. 85. 82.7 1978 82. 82. 84. 82. 82. 8. 81. 81. 81. 83. 84. 84. 82.2 1979 82. 83. 81. 82. 81. 83. 84. 83. 84. 84. 85. 81. 82.8 198 81. 81. 82. 86. 81. 8. 82. 83. 82. 83. 84. 81. 82.2 1981-83. 83. 82. - 8. 82. 8. 85. 85. 83. 83. 82.6 1982 83. 85. 84. 85. 85. 82. 83. 83. 84. - 89. 86. 84.5 1983 81. 85. 84. 84. 84. - 83. 83. 85. 84. 82. 85. 83.6 1984 79. 8. 85. 84. 83. 82. 84. 81. - 83. 87. 84. 82.9 1985 8. 82. 82. 83. 82. 81. 81. 82. 4. 83. 84. 83. 78.6 1986 83. 8. 86. 84. 83. 84. 82. 84. 83. 85. 84. 84. 83.5 1987 83. 83. 84. 85. 86. 83. 84. 85. 86. 89. 87. 84. 84.9 1988 86. 84. 87. 86. 84. 84. 82. 87. 88. 86. 88. 77. 84.9 1989 77. 78. - 78. 81. - 8. - 83. 84. 85. 81. 8.8 199 8.7 8.2 8.9 82. 8.6 81.1-78.6 82.4 84.8 83.9 83.1 81.7 1991 83.1 81.3-83.4 85.1 8.4 81.2 81.5 82.4 83.8 86.1 84.6 83. 1992 78.3 78.9 82.8 82.4 84.4 8.1 81.2 81.8 82.6 79.7 82.8 82.6 81.5 1993 8.5 8. 82.5 82.4 84.4 78.9 81.9 81.1 83.3 83.3 84.4 82.2 82.1 1994 83.2 8.7 82.5 81.8 81.5 81.9 78.2 81. 83. 85.1 87.1 83.9 82.5 1995 79.1-8.6 81.9 81.6 79.5 79.6-82.3 81. - 81.4 8.8 1996-79.4 - - - 82.1 79.7 8.3 - - 81.8 82.2 8.9 1997 76.8-77.5 83.2-81. - 81.5 84.6 - - 85.5 81.5 1998 82.9 83.2-83.2 81.6 8.7 79.3 82.6 83.8 81.7 83.7 83.9 82.4 1999 84. 81.1 8.4 78.2 82. 8. 79.7 81.8 83.2 83.1 83.8 81.7 81.6 2 78.7 73. 77.9 8.8 79.5 79.9 8.6 81.9 85.4 83.8 84.5 81.3 8.6 21 - - - - - - - - - - - - - 22 76.8 - - - - - - - - - - - 76.8 Min 76.8 73. 77.5 78. 79. 78.9 78.2 78.6 4. 79.7 81.8 77. Max 86. 85. 87. 86. 86. 84. 84. 87. 88. 89. 89. 86. Ave 81.1 81.3 82.4 83. 82.6 81.4 81.6 82.2 82.2 83.9 84.6 83.1 82.5 Source: (1971-1989) Masang-3 HEPP Report, 1999 (199-22) BMKG JICA Project for the Master Plan Study of T-2 August, 211

Table 3 Monthly Mean Sunshine Duration Station Name: Tabing-Padang Elevation: 2.m Unit: % Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average 1971 - - - 45. 36. 29. 26. 22. 19. 25. 15. 27. 27.1 1972 46. 34. 26. 29. 4. 42. 4. 4. 2. 1. 9. 35. 3.9 1973 56. 61. 47. 39. 53. 57. 65. 43. 34. 47. 44. 38. 48.7 1974 37. 55. 65. 63. 43. 56. 63. 5. 42. 38. 4. 5. 5.2 1975 5. 47. 54. 52. 69. 6. 61. 68. 55. 5. 46. 48. 55. 1976 59. 63. 5. 54. 74. 59. 66. 71. 51. 4. 36. 57. 56.7 1977 57. 44. 66. 55. 68. 64. 61. 58. 42. 4. 44. 62. 55.1 1978 4. 58. 53. 57. 49. 51. 56. 54. 42. 52. 45. 42. 49.9 1979 66. 51. 69. 45. 61. 56. 53. 56. 52. 43. 37. 68. 54.8 198 62. 68. 57. 44. 71. 59. 55. 32. 53. 57. 34. 46. 53.2 1981-5. 69. 62. - 81. 62. 82. 49. 48. 53. 67. 62.3 1982 68. 62. 56. 68. 56. 8. 78. 69. 44. - 4. 53. 61.3 1983 68. 62. 56. 68. 56. 8. 78. 69. 44. - 4. 53. 61.3 1984 42. 43. 45. 47. 63. 6. 47. 46. - 45. 52. 35. 47.7 1985 7. 5. 43. 41. 62. 52. 51. 53. 31. 41. 34. 6. 49. 1986 37. 66. 37. 6. 58. 6. 59. 48. 42. 39. 49. 62. 51.4 1987 46. 7. 54. 29. 67. 65. 73. 63. 4. 47. 48. 58. 55. 1988 61. 77. 56. 73. 72. 75. 76. 6. 45. 57. 34. 71. 63.1 1989 64. 59. - 8. 73. - 58. - 68. 49. 59. 67. 64.1 199 64.8 59.9 66.3 59.1 72.8 6.1-62.3 48.2 39.6 48.8 62.4 58.6 1991 57.9 67.6 65.4 62.5 6.7 78.3 75.1 63.3 27.9 25. 34. 36.1 54.5 1992 52.4 57.4 58.6 59.3 63.8 61.6 66.3 55.6 43.5 57.3 54.2 5.8 56.7 1993 61.6 72.3 46.2 64.6 46.7 68.6 59.7 66.4 55.1 46.7 42.6 51.7 56.9 1994 52.3 6.4 43.7 61.8 62.6 56.4 76.2 57.4 43.6 14.9 41.4 59.8 52.5 1995 53.1-53.4 55. 56.3 71.4 65.1-43.6 52.5-55.5 56.2 1996-51.3 - - - 61. 47. 42.8 - - 38.9 33.9 45.8 1997 43. - 63.6 62.2-76.8-47.3 - - - 47.1 56.7 1998 52.8 55.7 53.8 6.2 54.8 51.4 61.7 52. 38.4 36. 32.4 23.9 47.7 1999 23. 49.1 32.8 53.2 57.5 56.2 65.6 65.6 - - - - 5.4 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 43.8 - - - - - - - - - - - 43.8 Min 23. 34. 26. 29. 36. 29. 26. 22. 19. 1. 9. 23.9 Max 7. 77. 69. 8. 74. 81. 78. 82. 68. 57.3 59. 71. Ave 53.1 57.4 53.3 55.3 59.5 61.7 6.9 55.4 42.9 41.7 4.4 5.7 52.7 Source: (1971-1989) Masang-3 HEPP Report, 1999 (199-22) BMKG JICA Project for the Master Plan Study of T-3 August, 211

Table 4 Monthly Mean Wind Velocity Station Name: Tabing-Padang Elevation: 2.m Unit: m/sec Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average 1971 1.5 2.1 1.5 1.5 1.5 2.1 2.1 2.1 2.1 3.1 2.6 3.1 2.1 1972 2.1 2.1 2.1 2.6 2.1 2.6 2.6 2.6 2.6 2.1 2.6 3.6 2.4 1973 3.6 3.1 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.1 2.7 1974 1.5 2.6 2.6 2.1 2.1 2.1 2.6 2.1 2.6 2.6 2.6 1.5 2.2 1975 2.1 2.1 2.1 2.1 2.1 1.5 1.5 2.1 2.1 2.6 2.6 2.6 2.1 1976 3.1 6.2 6.7 3.1 1.5 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.9 1977 2.1 2.6 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 1978 2.1 2.1 2.1 1.5 2.1 1. 1. 1. 1. 1. 1. 1. 1.4 1979 1..5.5.5.5.5.5.5 1..5.5.5.6 198.5.5.5.5.5.5.5.5 2.1.5.5.5.6 1981 -.5 1. 1. - 1. 1..5 1..5 1. 1..9 1982 1. 1. 1. 1. 1. 1. 1. 1. 1. - 1. 1. 1. 1983 1. 1. 1. 1. 1. - 1.5 1. 1. 1. 1. 1. 1.1 1984 1. 1. 1. 1. 1. 1. 1. 1. - 1. 1. 1. 1. 1985 1.5 1. 1. 1. 1. 1.5 1. 1. 1. 1. 1. 1. 1.1 1986 1. 1.5 1. 1. 1. 1. 1. 1. 1. 1.5 1. 1.5 1.2 1987 1.5 1.5 1.5 1. 1.5 1. 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1988 1.5 1.5 1. 1.5 1.5 1. 1.5 1. 1.5 1.5 1.5 1.5 1.4 1989 1.5 1.5-1.5 1. - 1. - 1.5 1. 1.5 1. 1.3 199.1.2.1.1.1.2 -.1.2.2.2.2.2 1991.2.2 -.2.2.2.1.2.1.1.2.1.2 1992.3.2.1.1.1.1.2.1.1.1.1.1.1 1993.1.2.1.1.1.1.2.1.1.1.1.1.1 1994.1.1.1.1.1.1.1.2.2.2.1.1.1 1995.1 -.1.1.1.1.1 -.1.1 -.1.1 1996 -.2 - - -.1.1.1 - -.1.1.1 1997.1 -.2.2 -.1 -.2.2 - -.2.2 1998.2.2 -.2.2.1.1.1.1.1.1.2.2 1999.1.2.2.2.1.2.2.2.2.1.2.1.2 2.2.2.2.5.5.5.6.6.6.6.6.5.5 21 - - - - - - - - - - - - - 22 6.2 - - - - - - - - - - - 6.2 Min.1.1.1.1.1.1.1.1.1.1.1.1 Max 6.2 6.2 6.7 3.1 2.6 2.6 2.6 2.6 2.6 3.1 2.6 3.6 Ave 1.3 1.3 1.3 1.1 1..9 1.1 1. 1.1 1.1 1.1 1.1 1.1 Source: (1971-1989) Masang-3 HEPP Report, 1999 (199-22) BMKG JICA Project for the Master Plan Study of T-4 August, 211

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 Average 1979-4.7 3.6 4.1 - - - - - - - - 4.1 198 - - - - 4.2 4.7 4.3 4.5 2.9 3. 2.6 3.1 3.7 1981 4.8 3.8 - - 2.5 4.1 3.7 4. 3.1 2.6 4.1 4.6 3.7 1982 5. 3.7 3.1 2.8 3.2 2.1 3.9 5. 4.3 3.8 3.7 3.9 3.7 1983 4.6 4.7 4.9 4.3 4.1 4.5 4.4 4.1 4.2 4.3 3.8 4.1 4.3 1984 4.5 4. 4.3 4.3 4.3 4.4 4.6 3.4 3.4 4.1 5.2 4.6 4.3 1985 5.3 5.4 5.6 4.2 4. 4.5 3.8 4.4 3.5 - - - 4.5 Min 4.5 3.7 3.1 2.8 2.5 2.1 3.7 3.4 2.9 2.6 2.6 3.1 Max 5.3 5.4 5.6 4.3 4.3 4.7 4.6 5. 4.3 4.3 5.2 4.6 Ave 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/day Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average 1975 3.6 3.5 4.7 3.5 4.2 3.5 3.6 4. 3.6 5. 4.2 3.8 3.9 1976 3.6 3.7 5.5 4.5 4.1 4.5 4.2 5.7 3.4 4. 3. 3.4 4.1 1977 2.6 3.6 3.4 3.7 3.9 3.7 4.8 3.7 3. - 2. 3.9 3.5 1978 3.7 3.9 3.7 4.3 4. 4.7 5. 4.6 5.5 5. - 2.3 4.2 1979 3.9 3.3 3.4 4.4 4.9 3. 3.5 4.1 3.6 4.1-3.4 3.8 198-4.3 2.4 2.8 3.2-3. - - 3.7 2.5 4.2 3.3 1981 3.4 5.7 2.7-3.4 2.6 3.2 4.7-4.8 3.8-3.8 1982-4.3 2.9-3. 2.4 2.7 2.7 4.1 4.2 3.3 2.8 3.2 1983 2.2 2.9 3.5 3.5 3. 3.7 2.8 3.2 3.1 3.1 2.9 3.1 3.1 1984 3.5 3. 3.2 2.7 3.4 3.4 3.2 3.2 3.1 3.1 3.1 4.8 3.3 1985 3. 6.6 3.5 2.8 2.9-3.1 2.6 2.6 - - - 3.4 Min 2.2 2.9 2.4 2.7 2.9 2.4 2.7 2.6 2.6 3.1 2. 2.3 Max 3.9 6.6 5.5 4.5 4.9 4.7 5. 5.7 5.5 5. 4.2 4.8 Ave 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 Source: Masang-3 HEPP Report, 1999 JICA Project for the Master Plan Study of T-5 August, 211

Table 6 Monthly Rainfall Records (1/13) Station Name: Maninjau Station ID: 52B Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 144 176 89 267 177 142 67 126 82 122 262 173 1,827 197 156 9 128 143 11 11 39 15 42 363 314 13 2,117 1971 56 287 234 2 14 75 73 231 24 72 59 77 1,78 1972 37 148 25 84 73 145 29 54 16 46 7 172 1,25 1973 133 71-418 314 64 15 265 275 184 74 183-1974 79 229 15 294 22 26 112 237 493 261 248 11 2,639 1975 132 259 56 328 188 144 23 - - - - - - 1976 32 228 191 183 3 175 217 194 9 339 235 231 2,118 1977 25 79 135 296 153 13 128 124 14 134 278 235 2,19 1978 186 272 279 169 134 278 133 11 73 22 1 165 2,92 1979 - - - - - - - - - - - - - 198 66 89 177 134 352 38 428 35 436 598 152 58 3,67 1981 297 236 26 658 12 38 428 12 457 61 811 58 4,885 1982 297 254 437 228 321 248 254 329 217 315 336 297 3,533 1983 133 13 48 365 619 336 378 217 369 552 313 23 3,933 1984 4 264 368 431 353 421 451 274 783 42 811 433 5,391 1985 495 148 355 313 235 324 338 19 589 29 566 41 4,253 1986 25 186 451 332 529 238 664 474 47 558 753 178 5,83 1987 286 24 221 395 343 125 279 284 33 471 595 65 4,111 1988 - - - - - - - - - 233 1,88 412-1989 87 4 221 22 321 327 175 71 258 473 365 192 3,812 199 361 83 194 172 463 12 369 193 193 183 - - - 1991-129 - 153 538 - - 231 319-876 577-1992 42 134 154 564 129 17 2 353 294 365 38 17 2,82 1993 291 156 26 253 428 168 331 156 324 264-362 - 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 32 13 56 84 3 17 29 54 73 46 7 77 Max 87 4 451 658 619 421 664 474 783 61 1,88 65 Ave 224 18 237 286 271 21 246 215 316 32 411 294 3,199 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-6 August, 211

Table 7 Monthly Rainfall Records (2/13) Station Name: Limau Purut Station ID: 52C Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 - - - - - - - - - - - - - 197 - - - - - - - - - - - - - 1971 - - - - - - - - - - - - - 1972 - - - - - - - - - - - - - 1973 - - - 53 39 271 71 452 393 4 332 371-1974 157 218 2 578 469 259 196 237 59 314 41 41 4,38 1975 411 32 312 416 226 44 359 25 487 48-329 - 1976 182 33 246 39 97 249 265 215 273 869 691 288 4,14 1977 362 379 283 292 222 134 92-218 34 469 23-1978 - - - - - - - - - - - - - 1979 - - - - - - - - - - - - - 198 244 111 216 331 21 226 41 411 243 551-426 - 1981 - - - - - - - - - - - - - 1982 - - - - 15 - - 289 413 296 418 - - 1983 229 11 487 449 348 184 178 73 22 252 227 229 2,977 1984-19 - - - - - - - - - - - 1985 - - 183-127 185 115 171 272 21 365 219-1986 97 114 197 181 278 114 337 282 263 218 33 489 2,9 1987 462 223 365 377 164 198 182 51 517 33 48 318 4,99 1988 - - - - - - - - - - - 229-1989 3 334 27 1 335 65 276 247 396 273 511 381 3,326 199 452 257 38 288-344 432 77 514-318 338-1991 457 146 561 379 178 58 126 185 227 71 392 491 3,271 1992 1 238 316 152 387 59-367 22 251 224 22-1993 221 227 361 32 - - 274 15 263 677 427 477-1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 97 11 183 1 97 44 71 73 22 71 224 23 Max 462 379 561 578 469 344 432 51 59 869 691 491 Ave 283 222 33 327 25 171 237 258 343 36 4 339 3,491 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-7 August, 211

Table 8 Monthly Rainfall Records (3/13) Station Name: Padang Panjang Station ID: 53 Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 371 392 431 459 339 31 415 417 26 24 582 465 4,582 197 186 111 338 381 181 194 137 62 295 413 557 258 3,113 1971 243 168 448 22 195 176 229 29 416 384 4 518 3,66 1972 346 355 559 573 216 248 185 64 268 19 29 551 3,764 1973 247 252 32 947 763 247 411 1,88 943 72 786 95 7,656 1974 277 581 873 1,3 899 41 342 15 413 138 5 581 6,14 1975 224 236 134 339 169 86 23 38 321 262 287 354 2,923 1976 161 112 393 329 112 26 324 217 421 49 79 193 3,721 1977 - - - - - - - - - - - - - 1978 258 421 289 343 232 328 11 - - 572 451 348-1979 162 28 17 356 245 312 218 165 141 498 423 216 3,114 198 258 138 175 171 156 16 25 336 23 315 384 285 2,831 1981 - - - - - - - - - - - - - 1982 - - - 553 464 - - 232 187-334 - - 1983 59 62 6 292 346 192 229 413 194 233 29 239 3,14 1984 38 357 384 - - 251 215 - - - - - - 1985 - - - - 362 213 282 126 319 257 422 411-1986 327 138 447 457 4 82 217 172 64 625 366 58 4,343 1987 268 329 254 434 545 189 273 181 148 245 291 41 3,567 1988 279 184 317 312 181 29 162-48 411 621 314-1989 418 456 459 153 275 29 85 26 352 439 333 245 3,63 199 525 157 392 86 158 385 168 299 269 449 28 197 3,365 1991 277 26 274 361 22 83 43 179 182 135 634 469 3,117 1992 56 5 143 143 227 74 16 172 161 262 282 36 2,9 1993-173 158 138 45 66 212 31 224 245 215 214-1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - 42 - - 1999 398 315 566 321 232 - - 253 315 617 521 497-2 - - - - - - - - - - - - - 21 - - 444 - - - - - - - - - - 22 - - - - - - - 18 361 - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 56 5 6 86 45 66 43 31 141 19 215 193 Max 59 581 873 1,3 899 41 415 1,88 943 72 786 95 Ave 294 248 348 382 33 212 221 246 32 365 432 39 3,76 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-8 August, 211

Table 9 Monthly Rainfall Records (4/13) Station Name: Bukit Tinggi Station ID: 54 Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 - - - - - - - - - - - - - 197 - - - - - - - - - - - - - 1971 - - - - - - - - - - - - - 1972-154 196 29 194 17 27 - - - - - - 1973-84 124 238 174 111 85 258 156 251 6 13-1974 - - - - - - - - - - - - - 1975 - - - - - - - - - - - - - 1976 - - - - - - - - - - - - - 1977 - - - - - - - - - - - - - 1978 - - - 316 - - - - - - - - - 1979 - - - - - - - - - - - - - 198 - - - - - - - - - - - - - 1981 - - - - - - - - - - - 146-1982 - - - - - - - 93 - - - - - 1983 - - 196 - - - - - - - - - - 1984 - - - - - - - - - - - - - 1985 179 153 218-21 28 48 62 328 187 234 98-1986 231 58 415 242 136 12 9 68 172 223 167 16 2,28 1987 17 7 272 222 132 37 86 121 95 274 151 225 1,792 1988 - - - - - - - - - - - 196-1989 333-139 75 119 24 15 77 253 224 186 - - 199-463 - - - - - - - - - - - 1991 - - - - - - - - - - - - - 1992 - - 233 169 - - - 56 - - 29 154-1993 135 12 252 273 269 85 162 72 251 231 256 191 2,279 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 17 58 124 75 119 24 27 56 95 187 6 98 Max 333 463 415 316 269 12 162 258 328 274 29 225 Ave 197 155 227 218 175 73 86 11 29 232 192 156 2,21 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-9 August, 211

Table 1 Monthly Rainfall Records (5/13) Station Name: Baso Station ID: 54A Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 199 159 46 488 287 141 138 23 137 197 454 384 3,22 197 24 126 193 169 42 8 99 21 235 294 275 131 1,869 1971 132 114 192 36 48 92 9 23 262 3 67 29 1,826 1972 154 122 286 383 287 7 52 48 137 - - 157-1973 69 1 69 179 279 62 38 151 61 665-169 - 1974 73 22 13 257 168 141 92 122 45 74 79 244 1,933 1975 82 276 162 258 97 4 13 99 241 31 92 39 1,547 1976 - - - - - - - - - - - - - 1977 - - - - - - - - - - - - - 1978 127 - - 189 - - - - - 182 295 249-1979 285 452-19 - - - - 229 316 284 - - 198 89 166 355 172-175 - 165 - - - - - 1981 - - - - - - - - - - - - - 1982 - - - - - - - 55 7 - - - - 1983 266-293 255 - - - - - - - - - 1984 - - - - - - - - - - - - - 1985 - - - - - - - - - - - - - 1986 - - - - - - - - - - - - - 1987 - - - - - - - - - - - - - 1988 - - - - - - - - - 56-16 - 1989 273 84 118 23 128 87 56 149 154 243-239 - 199 7-1 65-55 - - - 164 - - - 1991 88 36 255 115 147 42 4 26 52-197 384-1992 85 38 141 53 21 2 164 35 158 66 - - - 1993 - - - - - - - - - - - - - 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 7 36 13 53 42 2 4 21 52 3 67 39 Max 69 452 46 488 287 175 164 23 45 665 454 384 Ave 182 158 199 222 168 82 86 111 182 193 218 21 2,12 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-1 August, 211

Table 11 Monthly Rainfall Records (6/13) Station Name: Padang Mangatas Station ID: 54C Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 253 26 336 357 299 6 47 166 54 26 454 44 2,878 197 177 181 269 195 17 46 55 35 86 149 255 168 1,723 1971 218 168 232 236 13 13 129 321 145 39 164 222 2,17 1972 147 86 252 369 217 158 4 129 148 12 179 288 2,115 1973 161 141 144 211 154 12 68 153 117 173 19 56 1,499 1974 3 188 72 233 111 121 246 152 345 77 126 98 1,799 1975 6 353 65 196 45 44 244 145 322 26 - - - 1976 143 71 257 173 17 16 14 115 148 289 328 348 2,225 1977 322 196 158 397 - - - - - - - - - 1978 - - - 313 153 61 179 76 46 34 229 462-1979 117 38 22 37 5 284-63 24 176 525 134-198 - - - - - - - - - - - - - 1981 - - - - - - - - - - - - - 1982 - - - - - - - - - - - - - 1983 241 - - - - - - - - - - - - 1984 - - - - - - - - - - - - - 1985 - - - - - - - - - - - - - 1986 - - - - - - - - - - - - - 1987 - - - - - - - - - - - - - 1988 - - - - - - - - - 19 81 259-1989 - 237 - - - 1 - - 131 - - - - 199 - - - - - 46 - - - - 17 45-1991 - 126 - - - - - - - - - - - 1992 - - - - - - - 24-37 219 398-1993 196 12 116 164 257 7 93 43 227-256 186-1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 3 38 65 37 45 1 4 24 24 26 19 56 Max 322 353 336 397 299 284 246 321 345 34 525 462 Ave 172 162 193 24 146 95 124 119 149 144 231 27 2,45 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-11 August, 211

Table 12 Monthly Rainfall Records (7/13) Station Name: Payakumbuh Station ID: 56 Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 159 14 387 133 222 3 3 81 84 89 34 444 2,76 197 313 75 241 197 84 71 136 96 23 223 189 127 1,955 1971 172 195 11 19 5 14 124 357 2 12 119 239 1,899 1972 196 96-495 478 29 148 76-83 173 - - 1973 154 11-345 275 128-298 182 - - - - 1974 48 182 89 443 199 129 121 15-38 96 121-1975 75 288 177 264 79 9 24 127 324 2 64 47 1,795 1976 82 47 23 169 69 155 146 21 18 24-319 - 1977 359 221 257 287 26 168 133 92 82 22 422 445 2,874 1978 32 178 483 321 239 82 117 33 93 32 254 469 2,891 1979 217 234 126 134 95 164 16 14 112 153 388 111 1,944 198 189 19 189 198 21 172 87 165 186 165 352 121 2,143 1981 189 - - - 21 175 87 165 - - - - - 1982 - - - - - - - - - - - - - 1983 167 84 - - - 34 126 65 149 33 47 - - 1984 186 169 - - - - - - - - - - - 1985 - - - 36 184 8 29 61 143 281 23 86-1986 47 74 638 143 227 43 43 31 24 256 18 18 2,66 1987 111 64 147 15 195 63 11 98 85 - - - - 1988 - - - - - - - - - 45 539 94-1989 - 291 - - - - - - - 424 - - - 199 - - - 584 231 36 475 3 764 1,313 212 258-1991 9 116 46 374 19 57 41 121 23 115 147 299 1,898 1992 142 3 89 19 31-77 6 68 35 482 7-1993 1 5 11 168 356 64 74 1 174 367 35 143 1,777 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 1 3 11 36 31 8 3 3 23 12 47 47 Max 359 291 638 584 478 29 475 357 764 1,313 539 469 Ave 16 137 238 249 187 11 121 111 181 232 251 21 2,181 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-12 August, 211

Table 13 Monthly Rainfall Records (8/13) Station Name: Koto Tinggi Station ID: 56A Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 - - - - - - - - - - - - - 197 - - - - - - 99 - - - 275 - - 1971 29 158 161 181 152 141 194 177 14 115 157 26 1,991 1972 174 156 216 23 156 151 9 25 15 222 184 1,97 1973 148 219 239 24 186 135 132 183 191 344 154 241 2,412 1974 129 193 191 287 239 191 185 197 355 193 276 286 2,722 1975 167 227 178 243 14 156 239 157 258 14 178 155 2,238 1976 171 16 185 489 194 243 257 275 237 314 35 23 3,33 1977 225 192 217 442 195 218 174 233 228 317 347 214 3,2 1978 191 184 27 312 19 58 149 133 164 371 281 32 2,56 1979 87 125 14 128 71 134 134 132 22 156 31 165 1,64 198 3 236 33 51 93 76 8 83 41 13 366 464 2,223 1981 137 239 225 319 413 69 18 45 27 141 246 366 2,515 1982 274 254 361 671 25 92 12 87 114 311 396 366 3,143 1983 184 9 214 21 18 114 133 12 227 224 294 33 2,212 1984 179 215 197 252 269 242 296 161 286 259 656 546 3,558 1985 189 186 3 185 262 175 97 126 281 32 315 182 2,618 1986 392 138 198 218 235 334 18 16 227 4 197 142 2,821 1987 227 8 297 425 349 65 17 31 71 41 25 272 2,881 1988 234 - - - - - - 194 289 21 38 129-1989 437 25 14 81 138 6 76 155 21 283 277 317 2,334 199 163 22 185 227 314 192 182 173 22 351 37 23 2,746 1991 339 95 447 24 266 67 95 68 71 241 265 845 3,39 1992 214 483 735 175 32 29 284 95 15 28 296 332 3,321 1993 172 132 397 231 285 91 256 122 16 76 38 247 3,179 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 3 8 14 81 71 29 8 22 13 154 129 Max 437 483 735 671 413 334 296 31 355 76 656 845 Ave 22 19 26 285 217 138 154 147 189 269 295 292 2,638 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-13 August, 211

Table 14 Monthly Rainfall Records (9/13) Station Name: Suliki Station ID: 56B Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 - - - - - - - - - - - - - 197 - - - - - - - - - - - - - 1971 148 19 111 127 14 96 136 124 95 76 18 146 1,38 1972 122 13 153 143 199 14 57 54 146 13 158 129 1,471 1973 3 14 83 244 85 12 41 145 131 159 19 119 1,172 1974 6 152 79 182 149 236 279 27 53 116 156 161 2,28 1975 61 152 79 185 16 43 189 45 21 17 78 42 1,117 1976 67 32 139 148 14 14 147 156 9 11 22 21 96 1977 151 16 128 187 13 9 6 12 121 215 383 112 1,722 1978 246 94 31 324 17 115 7 124 6 257 199 267 2,119 1979 149 12 217 128 51 27 181 236 165 16 53 383 2,482 198 82 8 128 151 145 126 76 83 129 167 379 186 1,732 1981 192 96 123 12 237 126 76 9 67 196 73 29 1,326 1982 47 89 194 354 177 114 119 86 271 176 253 12 1,982 1983 153 33 51 66 166 12 67 71 127 232 17 8 1,255 1984 172 194 277 186 184 146 156 18 149 7 353 282 2,187 1985 24 127 191 17 226 19 76 133 258 124 349 149 1,963 1986 283 98 418 223 194 72 41 29 13 197 181 229 2,95 1987 97 89 389 213 51 25 34 154 218 496 218 128 2,562 1988 488 294 451 388 115 89 142 412 351 62 558 88 3,438 1989 766 112 221 181 136 85 81 194 396 56 417 186 3,335 199 823 321 228 188 424 18 2 227 689 416 516 4,5 1991 68 192 1,486 1,92 365 22 65 92 297 364 722 1,441 6,926 1992 164 372 347 1 281 17 261 93 41 149 429 626 3,24 1993 515 321 162 376 598 14 19 19 79 1,545 853 489 5,917 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - 254 87 - - - - - - Min 3 14 66 9 6 11 22 21 Max 823 372 1,486 1,92 598 236 279 412 79 1,545 853 1,441 Ave 245 143 249 235 194 97 18 113 226 267 35 257 2,44 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-14 August, 211

Table 15 Monthly Rainfall Records (1/13) Station Name: Kota Baharu Station ID: 57 Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 - - - - - - - - - - - - - 197 - - - - - - - - - - - - - 1971 - - - - - - - - - - - - - 1972 - - - 362 382 146 44 61-319 346 - - 1973 183 261 349 379 348 219-25 239 - - - - 1974 61 276 154 217 135 127 99 74 143 153 93 253 1,785 1975 196 121 272 142 18 85 268 193 28 151 323 16 2,299 1976 123 114 89 89 64 123 58 211 151 372 - - - 1977 - - 22 234 22 42 14 31 148 63 27 216-1978 96 9-354 24 28-91 29-39 812-1979 275 459 278 372 182 13 16 129 36 288 53 374 3,132 198 374 38 313 328-117 149 83 315 93-142 - 1981 9 57 478 64 226 38 211 3 27 533 18 362 2,98 1982 - - 239-362 - - - - - - - - 1983 392 173-122 29 122 135 - - - - - - 1984 - - - - - - - - - - - - - 1985 - - - 75 26 2 94 57 366 254 226 289-1986 399 1 49 324 147 89 165 47-377 413 57-1987 24 234 321 175 433 - - - - - - - - 1988 - - - - - - - - - 179 146 - - 1989 466 159 45 247 238 47 57 186 416 446 42 382 3,451 199-468 - - 185 11 115 6 14 622 331 51-1991 463-48 623 21 36 23 13 219 146 42 874-1992 386 241 365 372 263 59 194 85 37 97 - - - 1993 - - - - - - - - - - - - - 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 61 9 89 64 22 2 14 6 29 63 93 142 Max 466 57 478 623 433 219 268 211 416 622 53 874 Ave 265 26 36 263 227 99 115 11 211 273 31 46 2,828 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-15 August, 211

Table 16 Monthly Rainfall Records (11/13) Station Name: Bonjol Station ID: 58C Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 - - - - - - - - - - - - - 197 - - - - - - - - - - - - - 1971 - - - - - - - - - - - - - 1972 - - - - - - - - - - - - - 1973 - - - - - - 12 393 374 416 33 341-1974 177 16 368 516 227 185 16 156 58 115 289 292 3,153 1975 159 175 15 374 74 14 286 8 131 251 9 223 2,133 1976 - - - - - - - - - - - - - 1977 - - - - - - - - - - - - - 1978 - - - - - - - - - - - - - 1979 - - - - - - - - - - - - - 198 - - - - - - - - - - - - - 1981 - - - - - - - - - - - - - 1982 - - - - - - - 291 347-477 - - 1983 224 143 546 925 56 357-42 492-766 - - 1984-453 451 - - 276 48 349 658 499 1,126 - - 1985 569 33 64 444 835 139 34 358 51 587 585 316 5,617 1986 423 165 496 487 523 359 512 453 494 664 348 119 5,43 1987 162 149 499 84 1,91 - - - - - - - - 1988 - - - - - - - - - 421 996 527-1989 262 37 277 243 424 131 267 416 637 681 742 181 4,631 199 - - - 47 32 - - - - 75-516 - 1991 391 211 622 548 274 189 119 23 433 437 794 655 4,93 1992-178 271 528 48 157 31 325 384 385 372 292-1993 272 267 481 419-2 399 237 312 563 482 481-1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 159 143 15 243 74 131 119 8 131 115 9 119 Max 569 453 622 925 1,91 359 512 453 658 75 1,126 655 Ave 293 236 433 521 474 213 291 39 44 477 567 358 4,613 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-16 August, 211

Table 17 Monthly Rainfall Records (12/13) Station Name: Jambak Station ID: 58F Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 - - - - - - - - - - - - - 197 - - - - - - - - - - - - - 1971 - - - - - - - - - - - - - 1972 - - - - - - - - - - - - - 1973 - - - - - - 144 36 284 43 162 218-1974 39 25 2 445 323 198 183 214 62 25 416 444 3,492 1975 117 288 344 493 287 117 478 236 495 237 259 293 3,644 1976 - - - - - - - - - - - - - 1977 285 22 265 844 211 268 155 37 295 523 6 252 4,27 1978 274 239 547 625 687 199 335 246 219 55 756 354 5,31 1979 24 264 339 35 136 354 551 312 282 372 716 247 4,82 198 177 219 589 587 555 262 3 256 292 469 391 51 4,598 1981 244 225 182 784 56 262 3 16 618 55 231 268 4,33 1982 113 31 493 41 37 144 199 149 273 276 49 22 3,285 1983 115 125 25 73 413 461 158 313 338 298 335 244 3,78 1984 268 213 22 751 222 19 383 159 415 296 786 289 4,192 1985 269 245 5 172 497 8 186 29 524 464 549 373 4,149 1986 411 119 433 241 359 271 226 153 3 431 585 248 3,777 1987 194 118 49 623 35 84 245 42 397 63 38 311 4,152 1988 298 149 368 34 185 188 115 479 334 2 191 499 3,13 1989 221 269 191 221 213 33 136 14 393 195 344 86 2,442 199 266 167 272 169 239 116 312 95 39 415 399 318 3,77 1991 252 2 482 464 32 151 138 95 47 47 713 57 4,325 1992 8 192 23 372 364 169 239 233 261 333 249 341 3,36 1993 226 147 424 34 438 24 27 197 333 456 442 445 3,823 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 39 118 182 169 136 33 115 95 219 2 162 86 Max 411 31 589 844 687 461 551 479 62 63 786 57 Ave 213 25 357 465 351 197 25 237 373 381 442 326 3,797 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-17 August, 211

Table 18 Monthly Rainfall Records (13/13) Station Name: Lubuk Sikaping Station ID: 59 Unit: mm Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1969 - - - - - - - - - - - - - 197 - - - - - - - - - - - - - 1971 314 288 289 3 285 279 36 298 279 266 287 313 3,54 1972 297 284 318 311 338 285 253 251 313 284 32 31 3,555 1973 255 246 284 374 286 245 36 298 279 266 287 313 3,439 1974 297 284 318 311 338 285 253 251 313 284 32 31 3,555 1975 255 246 284 374 286 245 144 359 283 43 165 218 3,289 1976 146 119 182 375 27 332 369 414 316 516 491 23 3,697 1977 285 22 31 844 211 268 155 37 295 523 6 252 4,243 1978 274 239 547 625 687 199 335 246 219 55 156 354 4,431 1979 24 264 279 3 136 354 551 312 282 372 216 247 3,517 198 177 219 589 587 555 262 3 256 272 473 48 328 4,426 1981 244 225 182 784 56 262 3 78 618 55 231 268 4,32 1982 71 263 556 365 412 192 219 43 228 216 49 127 3,11 1983 115 92 25 73 388 461 144 313 338 298 335 166 3,63 1984 268 177 187 34 261 19 383 148 415 296 786 246 3,697 1985 273 286 46 344 477 8 186 177 638 388 544 373 4,226 1986 411 24 175 335 357 298 28 146 284 427 - - - 1987 194 111 49 559 33 - - - - - - - - 1988 - - - - - - - - - - - 16-1989 - - - - - - - - - - - - - 199 - - - - - - - - - - - - - 1991 - - - - - - - - - - - - - 1992 - - - - - - - - - - - - - 1993 - - - - - - - - - - - - - 1994 - - - - - - - - - - - - - 1995 - - - - - - - - - - - - - 1996 - - - - - - - - - - - - - 1997 - - - - - - - - - - - - - 1998 - - - - - - - - - - - - - 1999 - - - - - - - - - - - - - 2 - - - - - - - - - - - - - 21 - - - - - - - - - - - - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 - - - - - - - - - - - - - 26 - - - - - - - - - - - - - 27 - - - - - - - - - - - - - Min 71 92 175 3 136 8 144 43 219 216 156 127 Max 411 288 589 844 687 461 551 414 638 55 786 373 Ave 24 223 335 462 36 265 28 244 336 384 37 262 3,76 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG JICA Project for the Master Plan Study of T-18 August, 211

Table 19 Selected Hourly Rainfall Records Unit:mm Total Hour Station Name Date Rainfall 1 2 3 4 5 6 7 8 9 1 11 12 Gunung 1982/12/12 55.2 1.2 8.5 2.6 1.8 16.1 4.5.2.6 3.7 4.7 2.3 Melintang 1983/1/12 59.9 4.9.2 1. 17.8 1983/3/22 59.4 13.3 3.3 7. 1.3 2.2 3.5 1.8 1983/4/3 55.4 14.5 33.3 5.3.7.1 1.5 1983/9/6 54.6 2.2 28. 5.3.8.3 1983/12/8 54.6 18.3 19.3 4. 5.3 4.8 2.9 1984/3/16 79.7 67. 8.5 4.2 1984/4/13 95.6.3 5.4 66. 11.7 1.8 2.1 3.2 2.1 1.7 1.1.2 1984/4/23 76.8 4.2 7. 2.6 1984/1/17 52.8 49. 2.3 1.5 1984/11/3 78.1 42.3 3. 4.3 1.5 1984/11/9 118. 18. 5. 45. 3.7 1.3 1984/11/18 55.3 4.2 37. 4. 2.5 3.3 1. 2.3 1. 1985/1/3 65.9 25. 25. 15..9 1985/1/6 51.3 44.5 2.5 1.2 2.1.8.2 1985/1/25 64.5 28.1 35.1.6.7 1985/2/11 95.1 3. 4.3 2.5 1.2 23.1 6..8.2 1985/3/11 99.5 6.6.5 15. 27.4 35. 14.2.8 1985/3/31 52.9 24.6 2.7 5.6 2. 1985/5/6 62. 3. 13.3 1.1 1.5 5.4 1.7 1985/5/14 132.6 5.2 5.5 7.2 2.2 13.3 31. 18. 4..7.4.1 1985/9/11 6.5 55. 3.9.9.7 1985/1/8 55.8 5.9.1 1.2 1.4 1.1.4.7 1986/3/9 76.2 4.5 32.4 3.1 1.8 3.7 1.3 6.2.3.1.9 1.3 2.6 Maninjau 1986/5/29 13.6 9.2 1. 1. 2. 4. 14.4 1986/7/8 116.8 2.6 43. 6. 11.2 1986/7/13 58. 11. 2. 2. 6.9.1 1986/8/3 55.6 1. 1.8.8 34. 4. 14. 1986/1/1 71.3 2.8.3.1.1 3.2 6. 2. 17. 3. 16. 1.8 1. 1987/8/1 83. 83. 1987/1/7 54.5 53.5 1. Sungai Talang 1991/9/29 7.5 68. 2..5 Barat 1991/12/28 68. 4. 2. 2. 2. 2. 12. 8. 3. 3. 4. 4. 4. 1992/3/8 66.2 1. 1.5 3. 4.2 8. 2. 4.5 2. 5. 8. Solok Bio-Bio 1991/1/18 63.7 3. 3.2 1.2.. 1.2 12. 25.1 1992/3/7 54.8 45.2.8 2. 1.2 5.6 Muara Paiti 1984/1/17 63.3 31.5 31.3.3.2 1984/11/3 87.5 5.3 5.3.2 32.7 41.1 1.5 1.4 1984/11/5 74.2 37.7 12.5 14.4.2.1 1.1 6. 2.2 1984/11/18 59.3 14. 32.9 2.6 3.2 1.5 4.5.4.2 1984/12/1 67.1 14.7 43.3 4.5 2.7 1.9 1985/2/1 99.9 42.2 5. 4. 3.6.1 1985/3/9 77.5 6. 8.2 8.9.3.1 1985/8/16 67.3 1.8 6. 3. 1.8.5.2 1985/1/6 55.8 4.9 5.5.8 1.6 2.1 3.4 1.3.2 1986/12/7 54.3 16.8 3. 5.2 2..3 1987/1/29 92.6 3. 4. 15. 6. 1.6 1987/2/8 65.5 7.4 4. 15. 3.1 1988/9/5 5.8 47.8 1.2.7.8.3 1988/9/11 82.5 22.5 45. 5. 7.7 2.3 1989/1/1 55.9 44.6 11.3 1989/1/16 61.4.9 2.6.6.2 14.2 2. 3. 1..9 1989/1/18 7.9 3.4 5.5 1.3.1 33.1 27.4.1 1989/6/25 52.4 17.5 19. 12. 1.7 1.5.7 1989/11/7 58.7 3.1 1.8 2.6 1.2 3.3.7 2.1 3.2.5 3.6.3.3 1989/11/13 51.6 33.2 9.2 6.7 2.5 Patir 1989/4/3 154. 3. 3. 1. 127. 13. 7. Puar Datar 1992/12/9 82. 34. 18. 7. 16. 6. 1. Halaban Dua 1991/8/3 82.2 49.3 28.1 4.8 1991/11/19 6. 1. 3. 2. 4. 14. 1991/12/14 76.8 3.8 34. 15.2 2. 8.1 11.3.9 1.5 1991/12/28 81.8 22.1 4. 7.1 19.2 8.1 11.2 6. 4..1 1992/4/23 8.3 6. 28. 1.2 32. 4. 5.1 4. Source:Masang-3 HEPP, 1999. JICA Project for the Master Plan Study of T-19 August, 211

Table 2 Monthly Mean Runoff Records Station Name: Sipisang Station ID: 1-164--1 Unit: m3/s Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 1975 - - - - - - - - 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. 62.8 2.7 1977 - - 18.8 2.4 2. 16.4 14.2 12.8 12.3 16.8 - - - 1978 2.9 18.4-18.9 13.7 - - 1.9 14. 16.4 25.6 21.6-1979 - - - - - - - 16.3-17.4 - - - 198 16.4 15.4 19.6 21. 15.8 19.3 16.4 - - - - - - 1981 - - - - 24.4 16.5 13.6 12.2 16.3 26.4 21.6 2.5-1982 16. 18. 2.5 27.2 29.4 18.2 14.7 13.9 12.9 14.3 18.2 23.3 18.9 1983 17.7 12.6 15.7 22.6 26.5 18. 15.7 16.3 21.4 19.2 18.9 18.3 18.6 1984 16.5 13.7 14.6 25. 17.3 16.4 14.5 12.7 16.9 21. 4.4 28.6 19.8 1985 25.3 21.6 25.1 23.3 24.3 22.9 17.6 14.5 2. 18.9 25.9 22.6 21.8 1986 22.6 17.3 25.4 23.7 35.8 24.8 19.3 19. 17.8 21.5 18.5 16.3 21.8 1987 13.1 1.2 14.9 18.1 25.1-1.3 24.1 - - - - - 1988 - - - - - - - - - - - - - 1989 - - - - - - - - - - - - - 199 - - - - - - - - - 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 2. 1992 - - - 17. - - - - - - - - - 1993 31. 36. 39.1 4.1 43.7 42.5 26.5 3.3 25.2 21.2 22.5 21.8 31.7 1994 21.8 19. 21. 21.3 22.1 16.2 17.6 17.8 15.2 12.1 22.9 32. 19.9 1995 22.3 24.4 21.9 25.4 26.1 21.5 17.3 19.6 18.6 25.2 21.8 23.4 22.3 1996 27. 28.7 29.4 29.5 2.2 23.8 17.3 18.7 18.1 23.2 26. 27.9 24.2 1997 17.6 12.4 13.8 15.9 16.5 9.7 8.4 7.7 7.9 8.7 1.4 12.1 11.8 1998 12.6 11.2 9.9 13.6 11.6 8.2 7.5 17.9 25.2 21.1 22.8 37.1 16.6 1999 33.7 22.2 23.6 18.2 16.8 11.4 14.9 16.1 27.2 34.3 45.5 49.3 26.1 2 34.2 18.6 18.2 2.4 15.8 14.1 16.1 15.1 13.9 18.5 59. 38.3 23.5 21-3.7 - - 12.1 12.3 7.4 - - 6.6 2.2 - - 22 - - - - - - - - - - - - - 23 - - - - - - - - - - - - - 24 - - - - - - - - - - - - - 25 2.5 19.9 2.7 34.2 21.9 16.4 17.9 18.2 38.4 41.6 46.8 36. 27.7 26 39.5 37.8 33.7 32.5 26.2 2. 22. 14.9 26.7 27.7 38.9 42.2 3.2 27 24.6 32.2 22.3 22.2 23. 17.5 26.9 25.9 36.3 26.9 3.7 25. 26.1 28 21.1 33. 25.9 3.3 24.5 29.4 38.7 47.6 38.2 4.1 36.2 31. 33. Min 12.6 3.7 9.9 13.6 11.6 8.2 7.4 7.7 2.9 6.6 2.2 12.1 Max 39.5 37.8 39.1 4.1 43.7 42.5 38.7 47.6 38.4 41.6 59. 62.8 Ave 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. JICA Project for the Master Plan Study of T-2 August, 211

Table 21 Regression Analysis of Monthly Rainfall Records Number of Data 52B 52C 53 54 54A 54C 56 56A 56B 57 58C 58F 59 Maninjau 52B 241 161 196 83 12 12 179 241 241 154 12 2 178 Limau Purut 52C 161 173 159 71 78 69 14 173 173 127 115 158 19 Padang Panjang 53 196 159 23 8 118 113 183 224 23 153 123 188 152 Bukit Tinggi 54 83 71 8 85 32 35 6 85 85 51 63 74 48 Baso 54A 12 78 118 32 118 75 94 118 118 89 69 9 8 Padang Mangatas 54C 12 69 113 35 75 12 18 12 12 78 51 78 96 Payakumbuh 56 179 14 183 6 94 18 24 24 24 154 1 167 15 Koto Tinggi 56A 241 173 224 85 118 12 24 27 27 179 132 228 196 Suliki 56B 241 173 23 85 118 12 24 27 276 179 132 234 196 Kota Baharu 57 154 127 153 51 89 78 154 179 179 179 93 156 133 Bonjol 58C 12 115 123 63 69 51 1 132 132 93 132 132 78 Jambak 58F 2 158 188 74 9 78 167 228 234 156 132 234 154 Lubuk Sikaping 59 178 19 152 48 8 96 15 196 196 133 78 154 196 Correlation Ratio 52B 52C 53 54 54A 54C 56 56A 56B 57 58C 58F 59 Maninjau 52B 1..269.162.275.194.146.123.248.274.144.572.331.286 Limau Purut 52C.269 1..341.236.441.348.364.339.322.262.26.413.277 Padang Panjang 53.162.341 1..185.24.131.274.198.81.247.254.187.128 Bukit Tinggi 54.275.236.185 1..548.655.651.529.53.668.445.565.582 Baso 54A.194.441.24.548 1..428.37.345.28.46.364.489.129 Padang Mangatas 54C.146.348.131.655.428 1..632.511.423.533.23.596.26 Payakumbuh 56.123.364.274.651.37.632 1..287.384.419.393.37.244 Koto Tinggi 56A.248.339.198.529.345.511.287 1..516.41.467.439.445 Suliki 56B.274.322.81.53.28.423.384.516 1..553.361.317.327 Kota Baharu 57.144.262.247.668.46.533.419.41.553 1..375.261.13 Bonjol 58C.572.26.254.445.364.23.393.467.361.375 1..619.68 Jambak 58F.331.413.187.565.489.596.37.439.317.261.619 1..78 Lubuk Sikaping 59.286.277.128.582.129.26.244.445.327.13.68.78 1. Slope of Formula (Y=aX) X 52B 52C 53 54 54A 54C 56 56A 56B 57 58C 58F 59 Maninjau 52B 1..851.647 1.562.997.945.846 1.34.824.888.727.828.752 Limau Purut 52C.834 1..731 1.45 1.56 1.59 1.193 1.87.691.976.633.818.816 Padang Panjang 53.94.962 1. 1.648 1.525 1.576 1.98 1.177.72 1.2.722.836.983 Bukit Tinggi 54.452.516.375 1..733.929.745.659.454.589.364.521.55 Baso 54A.539.464.374 1.4 1..894.562.668.388.529.385.476.558 Padang Mangatas 54C.597.48.357.91.737 1..828.81.658.647.44.53.532 Payakumbuh 56.544.549.498 1.33 1.7.959 1..734.534.695.416.517.511 Koto Tinggi 56A.626.685.543 1.223.958.972.786 1..668.741.529.634.626 Suliki 56B.585.723.542 1.383 1..921.911.925 1..823.61.654.421 Kota Baharu 57.592.683.61 1.445 1.257 1.135.867.941.768 1..541.621.566 Bonjol 58C 1.112 1.156.899 2.21 1.645 1.514 1.317 1.461.873 1.272 1. 1.26 1.235 Jambak 58F.86.975.789 1.62 1.514 1.547 1.126 1.212.821 1.31.73 1. 1.2 Lubuk Sikaping 59.934.941.695 1.696 1.147 1.36 1.347 1.292 1.663 1.117.682.9 1. JICA Project for the Master Plan Study of T-21 August, 211

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 Annual 1973 126 99 26 36 262 75 15 234 241 218 96 19 2,213 1974 89 213 122 281 217 242 145 225 462 231 245 15 2,622 1975 133 241 86 294 16 137 21 8 144 156 93 149 1,882 1976 67 193 184 25 48 187 219 29 116 3 23 24 2,27 1977 234 18 153 319 16 12 132 149 134 184 34 218 2,215 1978 193 234 266 217 15 211 124 111 87 246 152 211 2,22 1979 17 132 174 15 7 177 244 164 121 183 375 164 2,61 198 37 1 164 19 186 162 192 177 29 275 187 373 2,252 1981 178 165 175 365 17 16 215 62 249 313 41 335 2,797 1982 195 176 289 287 22 138 123 169 146 224 26 221 2,43 1983 114 3 229 29 36 18 199 127 222 31 212 176 2,314 1984 229 182 23 261 231 25 276 156 415 238 533 339 3,339 1985 275 119 24 187 183 181 174 123 342 21 349 232 2,615 1986 225 121 28 214 299 186 329 242 266 35 385 132 3,29 1987 184 114 22 288 277 71 162 28 168 345 323 334 2,675 1988 228 177 278 239 75 61 88 21 259 161 336 128 2,231 1989 397 174 15 86 124 53 7 138 21 265 256 254 2,121 199 21 184 169 192 279 149 167 133 197 337 281 228 2,516 1991 313 96 476 29 243 74 83 63 1 232 291 771 3,3 1992 176 397 582 156 278 31 243 9 157 183 267 314 2,874 1993 181 131 328 217 282 89 29 12 2 671 373 245 3,27 Min 37 3 86 86 48 31 7 62 87 156 93 128 Max 397 397 582 365 36 25 329 242 462 671 533 771 Ave 185 161 235 24 2 14 177 151 211 268 284 255 2,57 JICA Project for the Master Plan Study of T-22 August, 211

Table 23 Annual Rainfall Loss of Various River Basins in Sumatra No. Station River Gauge ID Catchment Basin Annual Annual Annual Runoff Observation Name Basin Area Mean Mean Runoff Rainfall Coeff. Period Rainfall Runoff Depth Loss (km 2 ) (mm) (m 3 /sec) (mm) (mm) 1 Lhok Nibong Kr. Jambu Aye 1-27-1-2 4,583 2,685 175.7 1,29 1,476.45 1972-1993 2 Stabat S. Wampu 1-4-1-1 3,87 3,99 26.8 1,685 1,414.54 1974-1993 3 Lb. Sipelanduk Bt. Pane 1-55-3-2 828 2,25 28.4 1,82 1,168.48 1973-1993 4 Lb. Bendahara S. Rokan 1-58-2-1 3,325 2,589 141.5 1,342 1,247.52 1974-1993 5 Tj. Ampalu Bt. Kuantan 1-66-4-1 2,215 2,211 77.6 1,15 1,16.5 1975-1993 6 Sungai Dareh Bt. Hari 1-71-1-1 4,452 3,239 31.2 2,197 1,42.68 1975-1993 7 Muara Inum Bt. Hari 1-71-2-1 1,455 3,346 17.6 2,332 1,14.7 1973-1987 8 Martapura A. Musi 1-74-1-1 4,26 2,821 225. 1,666 1,155.59 196-1984 9 Banjarmasin W. Tl. Bawang 1-77-2-7 64 3,125 36.8 1,921 1,24.61 1972-1993 1 Kunyir W. Sekampung 1-8-1-4 438 2,74 23.1 1,663 1,77.61 1968-1993 11 Kp. Darang Kr. Aceh 1-1-1-1 1,81 2,12 33.1 966 1,46.48 1977-1993 12 Tui Kareng Kr. Teunom 1-25-1-1 2,43 3,437 183.9 2,413 1,24.7 1982-1993 13 Hp. Baru Bt. Toru 1-178-1-1 2,773 2,843 128.9 1,466 1,377.52 1972-1993 14 Air Batu Bt. Indrapura 1-141-1-1 468 2,887 31.3 2,19 778.73 1973-1993 15 Air Gadang Bt. Pasaman 1-165-1-1 1,339 3,6 121.3 2,857 743.79 1973-1993 16 Despetah A. Musi 1-74-1-2 627 3,1 45.2 2,273 827.73 1974-1991 Source : Sectoral Report Vol. 2 : Hydrology, Hydro Inventory Study, July 1997 JICA Project for the Master Plan Study of T-23 August, 211

Table 24 Area Reduction Factor for Masang River Basin Maninjau Payakumbuh No Date Point Rainfall (mm) Area Average Reduction Maninjau Payakumbuh Factor 1 1973/9/19 115 58.5 2 1974/5/3 9 6 48.53 3 198/9/8 161 2 82.51 4 1984/1/9 91 45 68.75 5 1985/9/28 125 63.5 6 1986/11/26 148 74.5 7 1987/4/8 129 35 82.64 8 1988/11/23 175 44 11.63 9 1989/6/7 2 1.5 1 199/1/16 81 41.5 11 1991/12/29 126 53 9.71 12 1992/4/18 125 63.5 13 1993/9/14 115 58.5 14 1973/5/1 1 13 52.5 15 1974/5/26 65 33.5 16 1981/1/2 65 33.5 17 1983/9/5 37 55 46.84 18 1985/1/8 64 13 84.81 19 1986/9/28 1 79 4.51 2 1987/7/9 7 35.5 21 1989/2/21 2 57 3.52 22 199/7/23 2 1.5 23 1991/8/13 22 76 49.64 24 1992/4/1 3 95 63.66 25 1993/5/25 35 7 53.75 Average.58 JICA Project for the Master Plan Study of T-24 August, 211

Table 25 Annual Maximum 1-Day Rainfall at Payakumbuh Station Unit: mm Year Rainfall 1951 96 1952 1 1953 76 1954 68 1955 66 1956 67 1957 92 1958-1959 85 196 77 1961 84 1962 13 1963 49 1964 8 1965 75 1966 27 1967 25 1968 95 1969 94 197 75 1971 93 1972-1973 13 1974 65 1975 11 1976 79 1977 113 1978 14 1979 82 198 15 1981 65 1982-1983 55 1984 45 1985 13 1986 79 1987 7 1988 59 1989 97 199 2 1991 76 1992 95 1993 7 Source: BMKG. Masang-3 HEPP, 1999. JICA Project for the Master Plan Study of T-25 August, 211

Table 26 Calculation of Probable Maximum Precipitation (PMP) Annual Maximun 1-Day Precipitation at Payakumbuh Station Unit: mm Year Rainfall Max = 27 mm (1966) 1951 96 1952 1 n = 4 1953 76 X n = 96.1 mm 1954 68 S n = 47.1 mm 1955 66 X n-m = 91.6 mm 1956 67 S n-m = 38.2 mm 1957 92 1958 - X n-m / X n =.95 1959 85 S n-m / S n =.81 196 77 1961 84 Adjustment for Maximum Observed Event 1962 13 f X1 = 97% 1963 49 f S1 = 89% 1964 8 1965 75 Adjustment for Sample Size 1966 27 f X2 = 1.5% 1967 25 f S2 = 11.6% 1968 95 1969 94 Statistical Coefficient 197 75 K m = 15.5 1971 93 1972 - Adjustment for Fixed Observational Time Intervals 1973 13 f = 113% 1974 65 1975 11 Computation of PMP 1976 79 X n = f X1 * f X2 * X n 1977 113 = 93.6 mm 1978 14 S n = f S1 * f S2 * S n 1979 82 = 42.6 mm 198 15 X m = X n + K m * S n 1981 65 = 754. mm 1982 - PMP = f * X m 1983 55 = 852. mm 1984 45 1985 13 1986 79 1987 7 1988 59 1989 97 199 2 1991 76 1992 95 1993 7 JICA Project for the Master Plan Study of T-26 August, 211

Table 27 Ratios for SCS Unit Hydrograph t/t p q/q p...1.3.2.1.3.19.4.31.5.47.6.66.7.82.8.93.9.99 1. 1. 1.1.99 1.2.93 1.3.86 1.4.78 1.5.68 1.6.56 1.7.46 1.8.39 1.9.33 2..28 2.2.27 2.4.147 2.6.17 2.8.77 3..55 3.2.4 3.4.29 3.6.21 3.8.15 4..11 4.5.5 5.. JICA Project for the Master Plan Study of T-27 August, 211

Table 28 Average Rainfall Loss at Sipisang AWLR Station Monthly Runoff Sipisang Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1982 16 18 21 27 29 18 15 14 13 14 18 23 1983 18 13 16 23 26 18 16 16 21 19 19 18 1984 16 14 15 25 17 16 15 13 17 21 4 29 1985 25 22 25 23 24 23 18 14 2 19 26 23 1986 23 17 25 24 36 25 19 19 18 21 19 16 Adjusted Monthly Basin Mean Rainfall Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1982 195 176 289 287 22 138 123 169 146 224 26 221 1983 114 3 229 29 36 18 199 127 222 31 212 176 1984 181 143 182 26 182 197 218 123 328 188 42 267 1985 275 119 24 187 183 181 174 123 342 21 349 232 1986 225 121 28 214 299 186 329 242 266 35 385 132 Number of Days Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1982 31 31 31 31 31 31 31 31 31 31 31 31 1983 31 31 31 31 31 31 31 31 31 31 31 31 1984 31 31 31 31 31 31 31 31 31 31 31 31 1985 31 31 31 31 31 31 31 31 31 31 31 31 1986 31 31 31 31 31 31 31 31 31 31 31 31 Runoff Depth Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1982 9 12 116 153 166 13 83 78 73 81 12 131 1983 1 71 88 128 149 12 89 92 121 18 17 13 1984 93 77 82 141 97 92 82 71 95 119 228 161 1985 143 122 141 132 137 129 99 82 113 17 146 127 1986 128 97 143 134 22 14 19 17 11 121 14 92 Rainfall Loss in Rainy Season 1982.53 1983.449 1984.432 1985.431 1986.52 Average.473 JICA Project for the Master Plan Study of T-28 August, 211

Table 29 Probable Flood Hydrographs at Masang-2 Intake Weir Site Catchment Area = 443 km2 Unit:m3/s Time Return Period (year) (hour) PMF 4 2 15 1 8 5 3 2 1 5 3 2 14 14 14 14 14 14 14 14 14 14 14 14 14 1 34 125 114 19 13 1 93 85 79 7 61 53 47 2 128 446 42 384 36 347 32 29 268 231 195 167 143 3 2776 958 86 821 769 74 682 617 568 487 41 348 296 4 3952 1359 122 1165 191 149 966 874 84 689 578 49 416 5 4344 1493 1341 128 1198 1152 161 959 883 756 634 537 456 6 467 1398 1256 1199 1122 18 994 899 827 79 594 54 428 7 3267 1125 11 965 94 869 8 724 667 571 48 47 346 8 2426 838 753 719 674 648 597 54 498 427 359 36 26 9 1751 67 546 522 489 471 434 393 363 312 263 224 191 1 1211 423 381 364 341 329 33 275 254 219 185 159 136 11 823 29 262 25 235 227 29 191 176 153 13 112 97 12 56 2 181 173 163 157 146 133 124 18 92 8 7 13 382 14 127 121 115 111 13 94 88 77 67 58 52 14 192 75 68 66 63 61 57 53 5 44 39 35 32 15 87 39 36 35 34 33 32 3 29 27 24 23 21 16 5 26 25 24 24 23 23 22 21 2 19 18 18 17 26 18 18 18 17 17 17 17 16 16 16 15 15 18 16 15 15 15 15 15 15 14 14 14 14 14 14 19 14 14 14 14 14 14 14 14 14 14 14 14 14 Peak 4344 1493 1341 128 1198 1152 161 959 883 756 634 537 456 JICA Project for the Master Plan Study of T-29 August, 211

Table 3 Probable Floods under Various Schemes in Sumatra Catchment Probable Peak Discharge (m3/sec) No Scheme River Province Area Return Period (year) (km2) 2 2 1 2 1, 1, PMF 1 Tampur-1 Kr. Tampur D.I. Aceh 2,25 2,87 3,59 7,47 2 Teunom-1 Kr. Teunom D.I. Aceh 9 2,3 3,12 8,39 3 Aceh-2 Kr. Aceh D.I. Aceh 323 1,3 1,47 3,51 4 Lawe Alas-4 Lawe Alas D.I. Aceh 5,75 2,5 4,25 12,5 5 Peusangan-4 Kr. Peusangan D.I. Aceh 945 1,6 6 Lake Laut Tawar Kr. Peusangan D.I. Aceh 195 5 81 94 1,67 7 Residual Basin-1 Kr. Peusangan D.I. Aceh 16 36 53 6 1,2 8 Jambu Aye Kr. Jambu Aye D.I. Aceh 3,89 1,939 2,331 3,8 4,85 9 Rubek Kr. Jambu Aye D.I. Aceh 93 142 1 Residual Basin-2 Kr. Peusangan D.I. Aceh 128 32 48 55 94 11 Lalang S. Belawan N. Sumatera 254 25 41 61 12 Tembakau S. Percut N. Sumatera 171 14 23 34 13 Lausimeme S. Percut N. Sumatera 16 18 28 3 14 Helvetia S. Deli N. Sumatera 341 28 53 69 15 Namobatang S. Deli N. Sumatera 93 25 27 16 Baru S. Serdang N. Sumatera 671 47 75 94 17 Pulau Tagor S. Ular N. Sumatera 1,13 43 82 1,7 18 Karai S. Ular N. Sumatera 5 5 56 19 Brohol S. Padang N. Sumatera 759 39 72 94 2 Rampah S. Belutu N. Sumatera 423 18 29 37 21 Renun A. Renun N. Sumatera 139 58 74 82 96 1,9 22 Wampu S. Wampu N. Sumatera 1,57 2,97 23 Limang S. Wampu N. Sumatera 959 3 94 24 Sipan Sihaporas Sipan Sihaporas N. Sumatera 196 269 1,8 25 Batang Bayang-1 Bt. Bayang W. Sumatera 84 59 26 Batang Bayang-2 Bt. Bayang W. Sumatera 36 34 27 Muko-Muko Bt. Antokan W. Sumatera 248 44 74 93 12 28 Masang-3 Bt. Masang W. Sumatera 993 1,136 2,24 2,878 3,168 3,851 4,854 1,419 29 Merangin-5 Bt. Merangin Jambi 2,597 1,97 2,46 5,3 3 Lake Kerinci Siulak Jambi 916 59 1,538 2,177 2,464 3,12 4,92 13,347 31 Batang Hari Bt. Hari Jambi 4,452 1,937 4,192 5,63 6,25 7,61 32 Batang Hari (Alt.) Bt. Hari Jambi 3,825 1,664 3,62 4,814 5,331 6,531 33 Kiri-1 Bt. Kampar Riau 1,187 2,537 7,274 34 Kiri-2 Bt. Kampar Riau 552 1,446 35 Kapoernan Bt. Kampar Riau 699 2,181 36 Kotapanjang Bt. Kampar Riau 3,337 1,183 1,624 8, 11,4 37 Upper Sinamar Bt. Indragiri Riau 3,18 3,18 8,383 38 Sukam Bt. Indragiri Riau 36 1,755 39 Lower Kuantan Bt. Indragiri Riau 7,453 1,47 4 Ombilin Bt. Ombilin Riau 1,78 118 175 211 263 41 Musi (Intake Dam) A. Musi S. Sumatera 587 24 53 72 78 1,1 1,31 42 Musi (Regulation Dam) A. Musi S. Sumatera 3 79 138 175 19 226 277 43 Martapura Way Komering S. Sumatera 4,26 1,3 1,9 2,2 2,3 2,7 6,3 44 Lematang-4 A. Lematang S. Sumatera 1,321 1,87 2,43 5,5 45 Mine Mouth Steam Plant A. Lematang S. Sumatera 3,667 6,636 46 Ketaun-1 A. Ketaun Bengkulu 449 5 8 98 1,7 7,14 Masang-2 Bt. Masang W. Sumatera 443 456 883 1,198 1,341 4,344 Source: Hydro Inventory Study, Sectral Report Vol.2 Hydrology, July 1997. Masang-3 HEPP, 1999. JICA Project for the Master Plan Study of T-3 August, 211

Table 31 Calculations of Suspended Load in Masang River No Sampling Date Water Level Qw C Qs Remarks Site (m) (m3/s) (mg/l) (ton/day) 1 Intake Weir 21/1/6.84 29.2 422.33 1,58.92 2 Intake Weir 21/1/9.67 2.83 1,654.33 2,977.32 3 Intake Weir 21/1/22.59 15.48 31,518. 42,154.44 U 4 Intake Weir 21/1/25.69 19.86 384.67 66.6 5 Intake Weir 21/11/5.84 26.54 456.67 1,47.17 6 Intake Weir 21/11/21.93 34.21 1,726.67 5,13.59 7 Intake Weir 21/11/25 1.58 8.5 1,84.67 12,551.84 8 Intake Weir 21/12/5.88 3.96 1,492.33 3,991.9 9 Sipisang AWLR Station 21/12/21.2 15.7 68.67 89.41 D 1 Sipisang AWLR Station 21/12/25.24 17.9 262.33 387.35 D Legend U: The concentration value is not reliable and not considered in the determination of the suspended load rating curve. D: Sampling was carried out at the Sipisang AWLR Station and not considered in the determination of the suspended load rating curve. JICA Project for the Master Plan Study of T-31 August, 211

Table 32 Water Quality Analysis of Masang River No Water Quality Parameter Unit Sample-1 Sample-2 Sample-3 Date 21/1/25 21/11/25 21/12/25 Weather Clear Cloud Cloud 1 ph 8.9 8.11 8.11 2 Temperature 25.4 24.9 24.9 3 Total Hardness mg/l 123.7 131 126 4 Temporary Hardness mg/l 52.58 93 97 5 Suspended Matter mg/lit 136 299 295 6 Total Solid mg/lit 261 327 343 7 Ignition Residue mg/lit.8.7.7 8 Permanganate Value as O2 mg/lit 9.69 7.24 3.55 9 Carbonates as CaCO3 mg/lit 1.74 8.6 1 Bicarbonates as CaCO3 mg/lit 135.52 115 141 11 Calcium (Ca) mg/lit 37.48 41.64 39.89 12 Magnesium (Mg) mg/lit 7.34 6.57 6.37 13 Sodium (Na) mg/lit 8.36 11.52 9.9 14 Potassium (K) mg/lit 1.96 2.77 2.8 15 Iron (Fe) mg/lit 1.579.72 1.28 16 Manganese (Mn) mg/lit <.2.69.7 17 Copper (Cu) mg/lit <.1.8.8 18 Turbidity NTU 41 37 52 19 Color Pt-Co-Unit 2 1 kol 1 kol 2 Electric Conductivity µ/cm 254 313 33 21 Aluminum (Al) mg/lit 1.35 1 1.42 22 Silica (SiO2) mg/lit 46.52 17.7 22 23 Lead (Pb) mg/lit.8.42.42 24 Arsenic (As) mg/lit.24.2.25 25 Ammonium (NH4) mg/lit.784 <.2 <.2 26 Albuminoid mg/lit <.1 <.1 <.1 27 Nitrites (NO2) mg/lit.2.3.7 28 Nitrates (NO3) mg/lit.516.432.666 29 Sulfities (SO3) mg/lit.155.72 <.2 3 Sulfates (SO4) mg/lit 17.65 21.3 21.9 31 Chlorides (Cl) mg/lit 7.77 8.9 7.87 32 Phosphates (PO4) mg/lit.49 <.2 <.2 33 Oxygen (O2) mg/lit 7.31 6.79 7.17 34 Carbon Dioxide (CO2) mg/lit 1.73 - - 35 P-value as CaCO3 mg/lit.52 <.2 <.2 36 M-Value as CaCO3 mg/lit 25 24.8 24.8 JICA Project for the Master Plan Study of T-32 August, 211

Figure 1 Location Map of Meteo-Hydrological Stations JICA Project for the Master Plan Study of F-1 August, 21

Daily Rainfall Records BMG HPPS2 No. Station Name ID ID 1 Maninjau 52B 22-52-2 Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Remarks 2 Limau Purut 52C 22-52-3 3 Padang Panjang 53 22-53- 4 Bukit Tinggi 54 22-54- 1961-5 Baso 54A 22-54-1 6 Padang Mangatas 54C 22-54-3 1965-7 Payakumbuh 56 22-56- 192-8 Koto Tinggi 56A 22-56-1 9 Suliki 56B 22-56-2 1923-1 Kota Baharu 57 22-57- 11 Bonjol 58C 22-58-3 12 Jambak 58F 22-58-6 13 Lubuk Sikaping 59 22-59- Source: BMKG Monthly Rainfall Records BMG HPPS2 No. Station Name ID ID 1 Maninjau 52B 22-52-2 Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Remarks 2 Limau Purut 52C 22-52-3 3 Padang Panjang 53 22-53- 4 Bukit Tinggi 54 22-54- 1961-5 Baso 54A 22-54-1 6 Padang Mangatas 54C 22-54-3 1965-7 Payakumbuh 56 22-56- 192-8 Koto Tinggi 56A 22-56-1 9 Suliki 56B 22-56-2 1923-1 Kota Baharu 57 22-57- 11 Bonjol 58C 22-58-3 12 Jambak 58F 22-58-6 13 Lubuk Sikaping 59 22-59- Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. BMKG Figure 2 Availability of Climatic Records (1/2) JICA Project for the Master Plan Study of F-2 August, 21

Daily Runoff Records DPMA HPPS2 No. Station Name ID ID Remarks 1 Bt. Masang 1-164 - Sipisang --1 163-1-1 28years Source: Pusair Bandung Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Daily Water Level Records DPMA HPPS2 No. Station Name ID ID 1 Bt. Masang 1-164 - Sipisang --1 163-1-1 Source: BPSDA Bukit Tinggi Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Remarks Monthly Runoff Records DPMA HPPS2 No. Station Name ID ID 1 Bt. Masang 1-164 - Sipisang --1 163-1-1 Source: HPPS2 Report, 1999. Masang-3 HEPP Report, 1999. Pusair Bandung. Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Remarks Air Temperature BMG HPPS2 No. Station Name ID ID 1 Tabing-Padang 316 22-43-1 Source: BMKG Relative Humidity BMG HPPS2 No. Station Name ID ID 1 Tabing-Padang 316 22-43-1 Source: BMKG Sunshine Duration BMG HPPS2 No. Station Name ID ID 1 Tabing-Padang 316 22-43-1 Source: BMKG Wind Velocity BMG HPPS2 No. Station Name ID ID 1 Tabing-Padang 316 22-43-1 Source: BMKG Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Remarks Remarks Remarks Remarks Pan Evapolation Management No. Station Name Body 1 Lubuk Sikaping BMG 2 Tanjung Pati P3SA Source: Masang-3 HEPP Report, 1999 : Complite Data : Incomplite Data Year 1969 197 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 22 23 24 25 26 27 28 29 Remarks Figure 3 Availability of Climatic Records (2/2) JICA Project for the Master Plan Study of F-3 August, 21

B. A. Alahanpanjang Power House Site B. Masang Sipisang AWLR station B. Masang S. Guntung Masang-2 Basin 443km 2 Masang-2 Intake Weir Site B. Sianok Figure 4 Catchment Area of Masang-2 Intake Weir based on 1:5, map JICA Project for the Master Plan Study of F-4 August, 211

Final Report (Supporting_PreF/S) Monthly Mean Air Temperature St. Tabing-Padang Monthly Mean Relative Humidity St. Tabing-Padang 27. 85. Temperature ( ) 26.5 26. 25.5 Humidity ( % ) 84. 83. 82. 81. 8. 25. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month 79. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Monthly Mean Sunshine Duration St. Tabing-Padang Monthly Mean Wind Velocity St. Tabing-Padang 7. 1.4 6. 1.2 Duration ( % ) 5. 4. 3. 2. 1. Velocity ( m/s ) 1..8.6.4.2. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Monthly Mean Pan Evaporation St. Lubuk Sukaping Monthly Mean Pan Evaporation St. Tanjung Pati 6. 6. Evaporation ( mm/day ) 5. 4. 3. 2. 1.. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Evaporation ( mm/day ) 5. 4. 3. 2. 1.. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Figure 5 Variations of Principal Climatic Data JICA Project for the Master Plan Study of F-5 August, 211

Final Report (Supporting_PreF/S) Figure 6 Location Map of Hourly Rainfall Stations JICA Project for the Master Plan Study of F-6 August, 211

Final Report (Supporting_PreF/S) Accumulated Hourly Rainfall (mm) 16 14 12 1 8 6 4 2 Station Name: Gunung Melintang 1 2 3 4 5 6 7 8 9 1 11 12 Time (hour) Accumulated Hourly Rainfall (mm) 16 14 12 1 8 6 4 2 Station Name: Maura Paiti 1 2 3 4 5 6 7 8 9 1 11 12 Time (hour) Accumulated Hourly Rainfall (mm) Station Name: Maninjau, Sungai Talang Barat, Solok Bio-Bio, Patir, Puar Datar, Halaban Dua 16 14 12 1 8 6 4 2 1 2 3 4 5 6 7 8 9 1 11 12 Time (hour) Figure 7 Accumulated Hourly Rainfall Curves JICA Project for the Master Plan Study of F-7 August, 211

Final Report (Supporting_PreF/S) Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1975 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1976 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1977 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1978 Figure 8 Daily Runoff Hydrograph (1/7) JICA Project for the Master Plan Study of F-8 August, 211

Final Report (Supporting_PreF/S) Discharge (m3/s) Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1979 198 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1981 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1982 Figure 9 Daily Runoff Hydrograph (2/7) JICA Project for the Master Plan Study of F-9 August, 211

Final Report (Supporting_PreF/S) Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1983 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1984 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1985 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1986 Figure 1 Daily Runoff Hydrograph (3/7) JICA Project for the Master Plan Study of F-1 August, 211

Final Report (Supporting_PreF/S) Discharge (m3/s) Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1987 199 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1991 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec Figure 11 Daily Runoff Hydrograph (4/7) 1992 JICA Project for the Master Plan Study of F-11 August, 211

Final Report (Supporting_PreF/S) Discharge (m3/s) Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1993 1995 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1996 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1997 Figure 12 Daily Runoff Hydrograph (5/7) JICA Project for the Master Plan Study of F-12 August, 211

Final Report (Supporting_PreF/S) Discharge (m3/s) Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1998 1999 Discharge (m3/s) Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 2 21 Figure 13 Daily Runoff Hydrograph (6/7) JICA Project for the Master Plan Study of F-13 August, 211

Final Report (Supporting_PreF/S) Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 25 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 26 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 27 Discharge (m3/s) 1 9 8 7 6 5 4 3 2 1 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 28 Figure 14 Daily Runoff Hydrograph (7/7) JICA Project for the Master Plan Study of F-14 August, 211

Final Report (Supporting_PreF/S) 3. 2.5 24 Water Level (m) 2. 1.5 1..5. 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 3. 2.5 25 Water Level (m) 2. 1.5 1..5. 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 3. 2.5 26 Water Level (m) 2. 1.5 1..5. 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 3. 2.5 27 Water Level (m) 2. 1.5 1..5. 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec Figure 15 Observed Daily Water Level Records (1/2) JICA Project for the Master Plan Study of F-15 August, 211

Final Report (Supporting_PreF/S) 3. 2.5 28 Water Level (m) 2. 1.5 1..5. 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 3. 2.5 29 Water Level (m) 2. 1.5 1..5. 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec Figure 16 Observed Daily Water Level Records (2/2) JICA Project for the Master Plan Study of F-16 August, 211

Final Report (Supporting_PreF/S) Accumulation of annual rainfall at Maninjau station 8, 6, 4, 2, - y =.6675x 1971 1979 1978 1993 y = 1.472x - 19227-2, 4, 6, 8, Accumulation of average annual rainfall at surrounding stations Accumulation of annual rainfall at Koto Tinggi station 8, 6, 4, 2, - 1971 1993-2, 4, 6, 8, Accumulation of average annual rainfall at surrounding stations Accumulation of annual rainfall at Suliki station 8, 6, 4, 2, - y = 1.6882x - 4591 y =.656x 1971 1988 1987 1993-2, 4, 6, 8, Accumulation of average annual rainfall at surrounding stations Accumulation of annual rainfall at Jambak station 8, 6, 4, 2, - 1971 1993-2, 4, 6, 8, Accumulation of average annual rainfall at surrounding stations Figure 17 Double Mass Curves of Rainfall Records JICA Project for the Master Plan Study of F-17 August, 211

Final Report (Supporting_PreF/S) Figure 18 Thiessen Polygon JICA Project for the Master Plan Study of F-18 August, 211

Final Report (Supporting_PreF/S) 2,5 1993 Annual Runoff Depth (mm) 2, 1,5 1, 5 mm 7mm 1976 15mm 1991 1984 - - 5 1, 1,5 2, 2,5 3, 3,5 4, Annual Basin Mean Rainfall (mm) Figure 19 Relationship between Annual Basin Mean Rainfall and Annual Runoff Depth at Sipisang AWLR Station 4,5 4, mm Annual Runoff Depth (mm) 3,5 3, 2,5 2, 1,5 7 mm 1,5 mm 1, 5 5 1, 1,5 2, 2,5 3, 3,5 4, 4,5 Annual Basin Mean Rainfall (mm) Figure 2 Relationship between Annual Basin Mean Rainfall and Annual Runoff Depth of Various River Basins in Sumatra JICA Project for the Master Plan Study of F-19 August, 211

Final Report (Supporting_PreF/S) Figure 21 Concept of Composite Tank Model JICA Project for the Master Plan Study of F-2 August, 211

Final Report (Supporting_PreF/S) 1982/1 1982/7 1983/1 1983/7 1984/1 1984/7 1985/1 1985/7 1986/1 1986/7 7 6 5 4 3 2 1 Rain Observed Runoff Simulated Runoff 1 2 3 4 5 6 7 Figure 22 Comparison of Observed and Simulated Monthly Runoff at Sipisang AWLR Station JICA Project for the Master Plan Study of F-21 August, 211

Final Report (Supporting_PreF/S) % Observed Runoff (m3/s) Simulated Runoff (m3/s) Error % 4.39 36.45 1.8% 5% 28.62 28.94 1.1% 1% 25.94 26.4.4% 15% 25.12 25.32.8% 2% 24.38 24.22.7% 25% 23.31 23.4 1.2% 3% 22.63 21.33 6.1% 35% 21.51 2.57 4.6% 4% 2.72 2.4 3.4% 45% 19.22 19.7 2.5% 5% 18.91 19.34 2.2% 55% 18.26 18.87 3.2% 6% 18.3 18.52 2.6% 65% 17.64 17.77.7% 7% 17.18 17.11.4% 75% 16.35 16.84 2.9% 8% 15.92 16.3 2.4% 85% 14.71 15.35 4.2% 9% 14.47 14.71 1.6% 95% 13.66 14. 2.4% 1% 12.59 12.19 3.3% 5 45 4 35 3 25 2 15 1 5 Observed Runoff Simulated Runoff % 1% 2% 3% 4% 5% 6% 7% 8% 9% 1% Discharge (m3/s) Figure 23 Flow Duration Curve of Observed and Simulated Monthly Runoff at Sipisang AWLR Station JICA Project for the Master Plan Study of F-22 August, 211

Final Report (Supporting_PreF/S) 1973/1 1974/1 1975/1 1976/1 1977/1 1978/1 1979/1 198/1 1981/1 1982/1 1983/1 1984/1 1985/1 1986/1 1987/1 1988/1 1989/1 199/1 1991/1 1992/1 1993/1 7 6 5 4 3 2 1 Rain Observed Runoff Simulated Runoff 1 2 3 4 5 6 7 Figure 24 Simulated Long-term Monthly Runoff at Sipisang AWLR Station JICA Project for the Master Plan Study of F-23 August, 211

Final Report (Supporting_PreF/S) % Observed and Simulated Runoff (m3/s) % 62.84 5% 3.28 1% 26.69 15% 24.38 2% 22.98 25% 21.85 3% 2.51 35% 19.39 4% 18.82 45% 18.17 5% 17.66 55% 17.18 6% 16.54 65% 16. 7% 15.22 75% 14.57 8% 13.71 85% 12.86 9% 12.3 95% 11.1 1% 6.78 average 18.94 5 45 4 35 3 25 2 15 1 5 Observed and Simulated Runoff.1.2.3.4.5.6.7.8.9 1 Discharge (m3/s) Figure 25 Flow Duration Curve of Estimated Monthly Runoff at Sipisang AWLR Station JICA Project for the Master Plan Study of F-24 August, 211

Final Report (Supporting_PreF/S) Probability Estimated Runoff (%) (m3/s) % 78.99 5% 31.32 1% 26.31 15% 22.51 2% 21.43 25% 2.29 3% 18.91 35% 18.5 4% 17.35 45% 16.73 5% 16.19 55% 15.57 6% 15.29 65% 14.55 7% 13.81 75% 13.6 8% 12.31 85% 11.48 9% 1.99 95% 1.3 1% 6.32 Average 17.67 5 45 4 35 3 25 2 15 1 5 Masang-2 Intake Weir Site.1.2.3.4.5.6.7.8.9 1 Probability of Exceedence Runoff (m3/s) Figure 26 Flow Duration Curve of Estimated Daily Runoff at Masang-2 Intake Weir Site JICA Project for the Master Plan Study of F-25 August, 211

Final Report (Supporting_PreF/S) Figure 27 Location Map of Water Level Observation and Discharge Measurement JICA Project for the Master Plan Study of F-26 August, 211

Final Report (Supporting_PreF/S) 2. Maximum Water Level 2.1m 21/11/26 6: 1.5 Water Level (m) 1. Average Water Level.75m.5 Minimum Water Level.55m 21/12/23. 21/1/1 21/1/16 21/1/31 21/11/15 21/11/3 21/12/15 21/12/3 18 16 Maximum Runoff 156.61 m3/s 21/11/26 6: 14 Runoff (m3/s) 12 1 8 6 4 Average Runoff 25.68 m3/s Discharge Measurement Estimated Runoff with H-Q Rating Curve Minimum Runoff 13.6 m3/s 21/12/23 2 21/1/1 21/1/16 21/1/31 21/11/15 21/11/3 21/12/15 21/12/3 Figure 28 Result of Water Level Observation and Hydrograph Calculated with H-Q Rating Curve JICA Project for the Master Plan Study of F-27 August, 211

Final Report (Supporting_PreF/S) 2. 1.8 Q=36.55(H+.6)^2 1.6 1.4 Water Level (m) 1.2 1..8.6.4.2. Observation H-Q Rating Curve 2 4 6 8 1 12 14 Discharge (m3/s) Figure 29 H-Q Rating Curve JICA Project for the Master Plan Study of F-28 August, 211

Final Report (Supporting_PreF/S) Number of Data 14 12 1 8 6 4 2 2% 5% 13% Total Rainfall Depth >= 5mm 29% 48% 63% 73% 84% 87% 89% 94% 1 2 3 4 5 6 7 8 9 1 11 12 Time Duration (Hour) 1% 1% 9% 8% 7% 6% 5% 4% 3% 2% 1% % Number of Data 3 2 1 2% Total Rainfall Depth >= 1mm 4% 8% 8% 8% 8% 8% % % % 1 2 3 4 5 6 7 8 9 1 11 12 Time Duration (Hour) 1% 1% 1% 9% 8% 7% 6% 5% 4% 3% 2% 1% % Figure 3 Histogram of Rainfall Duration JICA Project for the Master Plan Study of F-29 August, 211

Final Report (Supporting_PreF/S) 1% 9% 8% 7% Accumulated Rainfall (%) 6% 5% 4% Design Pattern 5% Design Hyetograph 3% 2% Rainfall (%) 4% 3% 2% 1% 1% % 1 2 3 4 5 6 Time (hour) % 1 2 3 4 5 6 Time (hour) Figure 31 Accumulated Hourly Rainfall Pattern around Masang River Basin and Design Hyetograph JICA Project for the Master Plan Study of F-3 August, 211

Final Report (Supporting_PreF/S) 1..9.8 Area Reduction Factor.7.6.5.4.3.2.1. 5 1 15 2 25 Point Rainfall Depth (mm) Figure 32 Area Reduction Factor for Masang River Basin JICA Project for the Master Plan Study of F-31 August, 211

Final Report (Supporting_PreF/S) Figure 33 Frequency Curves of Probable Daily Rainfall at Payakumbuh station JICA Project for the Master Plan Study of F-32 August, 211

Final Report (Supporting_PreF/S) 11 15 1 Length of record (years) 1 15 2 95 3 5 X n adjustment factor (%) 9 85 8 75 7.7.75.8.85.9.95 1 X n-m / X n Source : Operational Hydrology Report No. 1 Manual for Estimation of Probable Maximum Precipitation Page 97, World Meteorological Organization, 1973 Figure 34 Adjustment of Mean of Annual Series for Maximum Observed Rainfall JICA Project for the Master Plan Study of F-33 August, 211

Final Report (Supporting_PreF/S) 12 11 1 9 Length of record (years) 1 15 3 5 S n adjustment factor (%) 8 7 6 5 4 3 2.2.3.4.5.6.7.8.9 1 1.1 S n-m / S n Source : Operational Hydrology Report No. 1 Manual for Estimation of Probable Maximum Precipitation Page 98, World Meteorological Organization, 1973 Figure 35 Adjustment of Standard Deviation of Annual Series for Maximum Observed Rainfall JICA Project for the Master Plan Study of F-34 August, 211

Final Report (Supporting_PreF/S) 13 125 12 Adjustment Factor (%) 115 11 Standard Deviation 15 Mean 1 1 15 2 25 3 35 4 45 5 55 Length of Record (years) Source : Operational Hydrology Report No. 1 Manual for Estimation of Probable Maximum Precipitation Page 99, World Meteorological Organization, 1973 Figure 36 Adjustment of Mean and Standard Deviation of Annual Series for Length of Record JICA Project for the Master Plan Study of F-35 August, 211

Final Report (Supporting_PreF/S) 2 15 K m 1 5 min 6 hours Duration 24 hours 1 hour 5 5 1 15 2 25 3 35 4 45 5 55 6 Mean Annual Rainfall (mm) Figure 37 Km as a Function of Rainfall Duration and Mean of Annual Series 114 112 11 Adjustment Factor 18 16 14 12 1 98 4 8 12 16 2 24 Number of Observational Units Source : Operational Hydrology Report No. 1 Manual for Estimation of Probable Maximum Precipitation Pages 96 &1, World Meteorological Organization, 1973 Figure 38 Adjustment of Fixed Interval Precipitation Amounts for Number of Observational Units within the Interval JICA Project for the Master Plan Study of F-36 August, 211

Final Report (Supporting_PreF/S) 3, Slope 2,5 Height (m) 2, 1,5 1, 5 - Tc=5.8hr Tc=.4hr - 1, 2, 3, 4, 5, 6, Distance (m) Figure 39 Slope of Masang River 25 2 Discharge (m3/s) 15 1 5 1 2 3 4 5 6 7 8 9 1 11 12 13 14 Time (hour) Figure 4 SCS Unit Hydrograph at Masang-2 Intake Weir Site JICA Project for the Master Plan Study of F-37 August, 211

Final Report (Supporting_PreF/S) 9 8 7 6 5 4 3 2 1 Daily Runoff Record as Sipisang Station Dischatge (m3/s) 1982/1/1 1982/2/1 1982/3/1 1982/4/1 1982/5/1 1982/6/1 1982/7/1 1982/8/1 1982/9/1 1982/1/1 1982/11/1 1982/12/1 1983/1/1 1983/2/1 1983/3/1 1983/4/1 1983/5/1 1983/6/1 1983/7/1 1983/8/1 1983/9/1 1983/1/1 1983/11/1 1983/12/1 1984/1/1 1984/2/1 1984/3/1 1984/4/1 1984/5/1 1984/6/1 1984/7/1 1984/8/1 1984/9/1 1984/1/1 1984/11/1 1984/12/1 1985/1/1 1985/2/1 1985/3/1 1985/4/1 1985/5/1 1985/6/1 1985/7/1 1985/8/1 1985/9/1 1985/1/1 1985/11/1 1985/12/1 1986/1/1 1986/2/1 1986/3/1 1986/4/1 1986/5/1 1986/6/1 1986/7/1 1986/8/1 1986/9/1 1986/1/1 1986/11/1 1986/12/1 Figure 41 Daily Runoff Hydrograph at Sipisang AWLR Station JICA Project for the Master Plan Study of F-38 August, 211

Final Report (Supporting_PreF/S) 45 4 35 3 25 2 15 1 5 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 Time (hour) PMF 4 2 15 1 8 5 3 2 1 5 3 2 Discharge (m3/s) Figure 42 Probable Flood Hydrographs at Masang-2 Intake Weir Site JICA Project for the Master Plan Study of F-39 August, 211

Final Report (Supporting_PreF/S) 1, Probable Maximum Flood Flood Peak Discharge (m3/s) 1, 1, 1 PMF C=92 Masang-2 PMF 1 1 1 1, 1, 1, Catchment Area (km2) 1, Return Period = 2 year Flood Peak Discharge (m3/s) 1, 1, 1 2 C=28 Masagn-2 2 1 1 1 1, 1, 1, Catchment Area (km2) Figure 43 Relationship between Probable Peak Discharge and Catchment Area in Sumatra (1/3) JICA Project for the Master Plan Study of F-4 August, 211

Final Report (Supporting_PreF/S) 1, Return Period = 1 year Flood Peak Discharge (m3/s) 1, 1 1 C=25 Masagn-2 1 1 1 1 1, 1, 1, Catchment Area (km2) 1, Return Period = 2 year Flood Peak Discharge (m3/s) 1, 1 2 C=19 Masagn-2 2 1 1 1 1, 1, 1, Catchment Area (km2) Figure 44 Relationship between Probable Peak Discharge and Catchment Area in Sumatra (2/3) JICA Project for the Master Plan Study of F-41 August, 211

Final Report (Supporting_PreF/S) 1, Return Period = 2 year Flood Peak Discharge (m3/s) 1, 1 2 C=1 Masagn-2 2 1 1 1 1, 1, 1, Catchment Area (km2) Figure 45 Relationship between Probable Peak Discharge and Catchment Area in Sumatra (3/3) JICA Project for the Master Plan Study of F-42 August, 211

Final Report (Supporting_PreF/S) Figure 46 Catchment Area of Regulating Pond based on 1:1, Map JICA Project for the Master Plan Study of F-43 August, 211

Final Report (Supporting_PreF/S) Masang-2 Basin 443. km 2 Alahanpanjang Basin 424.1 km 2 B. A. Alahanpanjang Intake Weir Site B. Masang Sub Basin 52.4 km 2 Power House Site Figure 47 Catchment Area of Power House Site based on 1:25, Map JICA Project for the Master Plan Study of F-44 August, 211