Table of Contents for Bayan 1 MHP Project Report

i
TABLE OF CONTENT
TABLE OF CONTENT .................................................................................................................................i
LIST OF TABLE......................................................................................................................................... iv
LIST OF FIGURE....................................................................................................................................... vi
INTRODUCTION.......................................................................................................................................1
1. Background .................................................................................................................................1
2. Objectives....................................................................................................................................3
3. Description of Bayan 1 MHP Project...........................................................................................4
4. Project Scope ..............................................................................................................................5
5. Civil Works ..................................................................................................................................5
SURVEY AND INVESTIGATION AT LOCATIONS OF CIVIL STRUCTURES.................................................15
1. TOPOGRAPHY SURVEY..............................................................................................................15
A. Aims of Survey.....................................................................................................................15
B. Results of Topography Survey.............................................................................................15
2. SOIL INVESTIGATION.................................................................................................................17
A. Drilling and SPT....................................................................................................................17
B. Geoelectrical Survey............................................................................................................19
C. Cone Penetrometer Test (CPT)............................................................................................35
DESIGN CRITERIA...................................................................................................................................38
1. PLANNING .................................................................................................................................38
A. Data and Reference to Consider for Planning.....................................................................38
B. Selection of Locations for Main Civil Structures..................................................................38
2. DESIGN FOR CIVIL STRUCTURES................................................................................................44
A. Weir Height Calculation.......................................................................................................44
B. Intake...................................................................................................................................46
C. Headrace..............................................................................................................................47
D. Headtank .............................................................................................................................48
E. Penstock ..............................................................................................................................50

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F. Foundation of Powerhouse .................................................................................................54
HYDROLOGY ANALYSIS..........................................................................................................................56
1. Introduction ..............................................................................................................................56
2. Hydrologic Data Collection........................................................................................................58
3. Data Consistency Test...............................................................................................................58
4. Maximum Daily Precipitation....................................................................................................62
5. Design Precipitation..................................................................................................................62
6. Riverflow Data...........................................................................................................................72
7. Unit Hydrograph .......................................................................................................................72
8. Design Flood..............................................................................................................................74
9. Dependable River Flow.............................................................................................................76
10. Design Flow for Bayan 1............................................................................................................79
HYDRAULIC ANALYSIS ...........................................................................................................................80
1. General......................................................................................................................................80
2. Waterway Rehabilitation ..........................................................................................................81
3. Design of Headpond..................................................................................................................83
4. Design of Penstock....................................................................................................................86
A. Data for penstock design.....................................................................................................86
B. Power Generation Capasity.................................................................................................87
C. Penstock diameter...............................................................................................................88
D. Head losses..........................................................................................................................88
E. Analysis of water hammer...................................................................................................91
F. Thickness of penstock pipe..................................................................................................98
5. Cavitation in Turbine.................................................................................................................99
6. Analysis of Tailrace during maximum flow .............................................................................101
STRUCTURAL CALCULATION ...............................................................................................................103
1. INFORMATION OF STRUCTURE DESIGN.................................................................................103
2. STRUCTURAL ANALYSIS OF WATERWAY.................................................................................104
3. STRUCTURAL ANALYSIS OF HEADPOND..................................................................................108
4. STRUCTURAL ANALYSIS OF PENSTOCK ...................................................................................118
5. STRUCTURAL ANALYSIS OF POWER HOUSE............................................................................126

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MECHANICAL AND ELECTRICAL CALCULATION...................................................................................171
1. TURBINE, GENERATOR AND CONTROL ...................................................................................171
A. Turbine...............................................................................................................................171
B. GENERATOR.......................................................................................................................174
C. CONTROL ...........................................................................................................................174
2. DISTRIBUTION LINES ...............................................................................................................180
A. DISTRIBUTION PATTERNS..................................................................................................180
B. Voltage Regulation Calculation of Distribution Line..........................................................187
C. Voltage Unbalance Calculation..........................................................................................188
3. Design of Earthing System for Powerhouse............................................................................191

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LIST OF TABLE
Table 1. Civil work for Bayan 1 project ...................................................................................................6
Table 2. Work of excavation and backfilling.........................................................................................14
Table 3. Lithology at the location of power house of Bayan 1 MHP ....................................................17
Table 4. Coordinates of the lines survey...............................................................................................19
Table 5. The resistivity and conductivity of rocks, soils and minerals (Loke M.,H, 2001) ....................21
Table 6. Values obtained from measurement at Bayan 1, Line 1, first measurement.........................22
Table 7. Comparation between three measurements in the same line measurement, Line 1 in Bayan
1 Teres Genit............................................................................................................................24
Table 8. The average of resistivity and conductivity in Line 1, Bayan 1................................................29
Table 9. The average of resistivity and conductivity in Line 2, Bayan 1................................................30
Table 10. The average of resistivity and conductivity in Line 3, Bayan 1 .............................................31
Table 14. Locations of test points at Bayan 1 (Teres Genit) MHP Project............................................35
Table 15. Results of CPT test at the location of headpond...................................................................35
Table 16. Results of CPT test at the location of penstock.....................................................................36
Table 17. Catchment area of Bayan 1...................................................................................................56
Table 18. Monthly basis datain Santong Station ..................................................................................59
Table 19.Maximum value of Q/n0.5
and R/n0.5
.......................................................................................60
Table 20. Consistency test for Santong precipitation data...................................................................61
Table 21. Factor reductionARF..............................................................................................................62
Table 22. The daily maximum precipitation after corrected by ARF ....................................................63
Table 23.Value of parameters on selection of the most suitable distribution.....................................64
Table 24. Parameters calculationon selection of the most suitable distribution.................................65
Table 25.The maximum value of max in Smirnov-Kolmogorov test.....................................................66
Table 26. The critical value (X2
Cr) for Chi square test..........................................................................68
Table 27.Analysis of Chi square test in Santong ...................................................................................69
Table 28.The frequency factor, K for negative Cs.................................................................................70
Table 29. The frequency factor, K for possitive Cs................................................................................70
Table 30.The design precipitationin the study area .............................................................................70
Table 31.The hourly precipitation distribution.....................................................................................71
Table 32. Design of hourly precipitation for every return period.........................................................71
Table 33. Values of unit hydrographs and the average of unit hydrograph.........................................74
Table 34. The effective precipitation....................................................................................................75
Table 35. Values of the design flood hydrograph in Bayan 1 (Teres Genit) .........................................76
Table 36. The half-monthly average river flow dataof Santong Station...............................................77
Table 37. Values of flow duration curvesin Bayan 1.............................................................................78
Table 38. Design of headpond in Bayan 1.............................................................................................84

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Table 39. Design of spillwayforBayan1 .................................................................................................85
Table 40. Technical Data for Bayan 1....................................................................................................86
Table 41. Energy loss due to the friction of Penstock for Bayan 1 ......................................................90
Table 42. Energy loss due to bends effects of Penstock for Bayan 1...................................................90
Table 43. Data for the analysis of water hammer ................................................................................92
Table 44. Analysis of water hammer ....................................................................................................94
Table 45. Design results of pipe thickness............................................................................................98
Table 46. Specification of turbine.......................................................................................................171
Table 47. Voltage drop calculation at Load 2 until Load 8 on Bayan MHP.........................................188
Table 48. Voltage drop calculation at Load 2 until Load 8..................................................................193

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LIST OF FIGURE
Figure 1.Layout of Location Bayan 1.......................................................................................................7
Figure 2. Birdview plan of Bayan 1..........................................................................................................7
Figure 3.Component Activity of Bayan 1 ................................................................................................8
Figure 4.Waterway Improvement of Bayan 1.........................................................................................9
Figure 5. Plan View of Headphone for Bayan 1 ....................................................................................10
Figure 6. Long sectional of Headphone for Bayan 1.............................................................................10
Figure 7. Headphone Bird View of Bayan 1 ..........................................................................................10
Figure 8. 3D Viewof Headpond.............................................................................................................11
Figure 9. Penstock View........................................................................................................................12
Figure 10. 3D View of Penstock ............................................................................................................12
Figure 11. Power House Plan of Bayan 1 ..............................................................................................13
Figure 12. 3D View of Power House .....................................................................................................13
Figure 13. Map of topography and existing condition at Bayan 1 MHPP location...............................16
Figure 14. Results of drilling log of soil investigation............................................................................18
Figure 15. Location of geoelectrical survey in Bayan 1 MHP................................................................20
Figure 16. The resistivity and conductivity of rocks, soils and minerals (Loke M.,H, 2004) .................21
Figure 17. Diagram of average resistivity in Bayan 1, Line 1 to Line 4. The vertical axis stands for
depth measured from land surface......................................................................................25
Figure 18. Diagram of average resistivity in Bayan 1, Line 4 to Line 6. The vertical axis stands for
Figure 19. Diagram of average conductivity in Bayan 1, Line 1 to Line 4. The vertical axis stands for
Figure 20. Diagram of average conductivity in Bayan 1, Line 4 to Line 6. The vertical axis stands for
Figure 21. The soil condition at the location of power house (S-03) at the depth of 0.6m .................37
Figure 22. Location of study areas, inzet: Lombok Island.....................................................................57
Figure 23. Hydrologic stations available in Lombok Island...................................................................57
Figure 24.Yearly precipitation data in Santong Station.........................................................................58
Figure 25. Smirnov-Kolmogorov Test for Santong Station ...................................................................67
Figure 26. The daily average riverflow..................................................................................................72
Figure 27. Hourly riverflow in December 2014.....................................................................................72
Figure 28.Several unit hydrographs obtained and the average of unit hydrograph ............................74
Figure 29. Design of flood hydrograph for Bayan 1..............................................................................75
Figure 30. Flow duration curvefor Bayan 1...........................................................................................78
Figure 31. Sketch location of spillway in headpond .............................................................................85
Figure 32. Long section of Penstock pipe .............................................................................................87
Figure 33. Sketch of Bayan 1 MHPP....................................................................................................100
Figure 34. Plan View of Headpond for Bayan 1 ..................................................................................108
Figure 35. Long Sectional View of Headpond for Bayan 1..................................................................108
Figure 36. Cross Sectional View of Headpond for Bayan 1.................................................................108

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Figure 37. Cross Sectional View of Power House for Bayan 1 ............................................................126
Figure 38. Efficiency and Debitgraph of Bayan 1................................................................................172
Figure 39. Plan of Turbine Bayan 1 .....................................................................................................172
Figure 40. X View of Turbine Bayan 1 .................................................................................................173
Figure 41. Y View of Turbine Bayan 1 .................................................................................................173
Figure 42.Type Generator Bayan 1 .....................................................................................................174
Figure 43. Basic wiring diagram of the digital load control with 2 steps ballast load ........................176
Figure 44. Droop application in parallel operation of MHP................................................................177
Figure 45. Application of Synchronizer for parallel operation of MHP...............................................178
Figure 46. Actuator .............................................................................................................................179
Figure 47. MicroGrid Scheme .............................................................................................................180
Figure 48. Distribution Line of Bayan..................................................................................................181
Figure 49. Distribution Line on RBI Map.............................................................................................182
Figure 50. Design of Electricity Network for Bayan MHP ...................................................................186

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INTRODUCTION
1. Background
Electric power is one of the main components in creating and improving the
welfare of the people and educating the nation. Without electricity, the
accelerated development of all sectors cannot be achieved. Almost every sector
of development requires electric power as a driving force of its activities. Electric
power development plays an important role for the national and public interest. It
can improve the quality of Indonesian human life and society and can also
increase the productivity of the people in order to achieve economic
independence.
Development of the electricity sector in NTB is quite apprehensive. It can be seen
from the Level of Electrification (LE) until the year of 2014 only about 68.05%,
which means that 31.95% or 42.458 households in NTB have no acces to
electricity yet. These figures are very low when compared with the national
average LE of 84.35%.
In the crisis of electricity supply including its network, various methods were
implemented by the government to improve equitable distribution of electricity in
the province. One of them was to build Self-generating unit of non-grid in the
remote areas such as the development of micro-hydropower plant (MHP) in the
village of Bayan (Teres Genit & Sembulan) and the village of Santong. The MHP
located in the hamlet of Teres Genit namely BAYAN_1 was built in 2008 with
capacity of 35kW by utilizing agricultural irrigation water sources. Meanwhile
BAYAN_2 was located downstream of BAYAN_1, precisely in the hamlet of
Sembulan. This MHP was built in 2011 with capacity of 50 kW using technical
irrigation as a water source. Both MHP are still functioning until now and serving
nearly 1100h ouseholds. While Santong_1 MHP was built in 2000 with a capacity
of 25 kW, and the Santong_2 MHP was built in 2008 with a capacity of 15 kW,

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unfortunately these MHPs are now no longer working since 2010 and even all its
mechanical and electrical equipment were lost.
The Bayan MHP Project in Bayan village includes several project activities, i.e
capasity building of MHP Project with the addition of micro hydro plants at Bayan
1 (Teres Genit Hamlet) with a capacity of 1 x 30 kW, Bayan 2 (Sembulan Hamlet)
with a capacity of 2 x 30 kW, and Bayan 3 (Kokok Muntur Hamlet) with a capacity
of 2 x 200 kW.
Three of the proposed projects in Bayan village are an effort to develop the
existing Bayan MHP. The existing MHP were built in 2008 and 2011 through the
Indonesian Ministry of Disadvantaged Regions to overcome the limited grid, with
a capacity of 35 kW and 50 kW respectively. Until now, the MHP are still working
with operating hours between 17.00 pm to 12.00 am or 16-19 hours per day.
Power plants are switched off between the hours of operation in order to avoid
damage. Therefore, new power plants are proposed to sustain the flow of
electricity up to 24 hours and to increase its capacity. MHP of Bayan 1 (Teres
Genit) will be placed beside the existing MHP, and position of the new power
house is lowered 2 m from the old position.
The enhancement of Bayan MHP should be done considering the following
points: (1) to improve services quality ofexisting MHP in terms of both capacity
and service time. With the customers of 1200 HH, it is required minimum power
supply of 1.05MW but only 85KW power available. Service time available
currently is only 15 to 18 hoursper day. Each day between the hours of 12:00 to
17:00, the power plant is turned off to reduce wear; (2) The potential availability
of natural resources in the form of water flow and head sufficient to drive a
turbine; (3) The public interest to continue using electricity MHP is still very high
compared to the interest in the grid, because it is cheap and stable power; (4)
With engineering management system then these problems can be overcome so
that electricity can be operated during the day; (5) With the existence of MHP,
Bayan community more concerned to preserve the surrounding forest in order to
maintain continuity of water supply. Because of the MHP, the Bayan community
has very strict rules in keeping changes in surrounding natural indigenous forest.
Sanctions applied to anyone felling trees, etc. with a fine number of buffalo; (6)

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more than 90% of the Bayan communities are categorized poor;the high number
of poor people who will be using the MHP are spread over 28 hamlets. There are
about 1200 households and 461 households in Bayan and Santong respectively.
In the Santong village only 18% of poor households have been using electricity.
While in Bayan village there are 81% of household using electricity of existing
MHP; (7) Bayan communities are ready to manage MHP as indicated by the
existing management organization, which is able to maintain continuity of MHP
operation independently.
2. Objectives
The objectives of projects are:
 Improving the welfare of rural communities by providing cheap electricity.
 Improvement of the poor incomes through economic activities by taking
advantage of cheap electricity
 Improvement of public awareness of the environment by maintaining the
continuity of forest and water resources in order to ensure sustainability of
MHP operation.
 Improvement of public social services through the supply of electricity for
public facilities
 Improvement of rural income from results of MHP business profit.
 Improvement of technical capabilities and management of MHP through
the development of training centers.
 Improvement of welfare of rural communities by economic development
programs and education for the poor, gender, and migrant workers,
financed by the proceeds of electricity sales.
Project targeted are:
 Construction of Micro Hydro Power Plant (MHP) in the village of Bayan
 Construction of electrical distribution line by targeting poor communities,
gender, migrant workers and minorities.
The proposed MHP project will serve the village of Bayan. The MHP is located at
Village of Bayan, Bayan District, North Lombok, NTB. GPS coordinates of the
project are:

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Weir : 8o
16‟56,1” South latitude and 116o
25‟10,26” East longitude
Head pond : 8o
Power house : 8o
MHP Bayan 3 (Kokok Muntur) is proposed in an attempt to increase the power,
because the electricity generated by the MHP Bayan 1 & 2 only produced
electricity power of around 175 kW while number of recorded customers more
than 1100 households. Therefore, additional power is needed to overcome this
deficit. This proposal actually has not been included in the concept note, because
of recently discovered. This proposal has been communicated with MCA-I and
permitted to be included in the project proposal that is part of this report. Finally,
the description is summarized in Table 3-1 above.
3. Description of Bayan 1 MHP Project
The proposed Bayan MHP project consists of two plants that will serve the village
of Bayan. The MHP are located at: (1) hamlets of Teres Genit; and (2) Hamlet of
Sembulan, Village of Bayan, Bayan District, North Lombok, West Nusa
Tenggara. Every locations has different condition, consequently, component of
work in every location is not the same.
GPS coordinates for the power house of the Bayan 1 project is 8o
18‟21,63” South
latitude and 116o
25‟1,7” East longitude. There is an existing MHPP in Bayan 1.
This MHPP is running well, however it works only at night in order to prolong life
time of the machine. The new Bayan 1 MHPP is designed to work during day
time, and it is placed in the same location, near the existing one. Waterway is the
same as used by the existing one, but at some locations need to be renovated.
Components of civil works in Bayan 1 MHPP consist of:
- Renovation of waterway
- Headpond
- Penstock
- Power house

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4. Project Scope
The MHPP of Bayan 1 is included in the scope of the projects as follows:
1. The development of micro hydro power plant (MHP) includes the
following activities:
1) Development of Teres Genit (Bayan 1) MHP with capacity of 1 x30
KW.
2) Development of Sembulan (Bayan 2) MHP with capacity of 2 x 30
KW.
3) Development of Kokok Muntur (Bayan 3) MHP with capacity of 2 x
250 KW.
4) Development of Santong MHP with capacities of 1 x 130 KW, and 2
x 250 KW.
5) Development of medium voltage lines with a length of 8,5 km, low
voltage 5,5 km and in-home linesof 825 houses.
6) Development of medium voltage lines with a length of 6,1 km, low
voltage lines of 2,8 km and in-home lines of 426 houses.
2. Procurement of automatic weather stations of 2 units.
3. Development of micro hydro workshop and training center.
4. Training of economic empowerment based on local potential.
5. Training for operational MHP
6. MHP operational until 2018
7. Projects operation and supervision
5. Civil Works
In general, civil works are all MHP components to deliver water to the turbine,
which consists of the works of waterway, headpond, penstock and power house.

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Table 1. Civil work for Bayan 1 project
No Activities Construction Volum Completeness
1 Improvement of road
access to the location
of the power house
unreinforced
concrete
1m wide, 8 cm thick
and 900 m length
Bridges at two points
2 Waterway
rahabilitation on
several segments
Reinforced
concretewith 12
cm thickness, U
shape
12 thickness, 1.5m
wide, 1.2m high, the
total length of about 87
m.
3 Construction of
headphone
Reinforced
concrete pools,
15 cm thick
Length: 5.3 m, Width:
2.4, Depth: 2.4 m
Sluice gates, trash
rack
4 Construction of
Spillway
15 cm thickness
of reinforced
concrete
Length: 3.0 m,
5 Penstock
1. Saddle support reinforced
concrete
Concrete size 1,2 x
0,6m, the amount of 9
units, foundation
strauss
2. Anchor block reinforced
concrete
Concrete size of 1.2 x
1.5 m, the number of 2
units, foundation
strauss
3. Penstock black steel pipe Diameter of 60 cm, 52
m length
Steel anchor, ring
plate, expantion
joint,
6 Power House Foundation;
reinforced
concrete
Walls: plastered
bricks masonry
Roof: steel
frame with
spandec covered
Size of 7 x 5 m Turbine foundation,
generator foundation
and tailrace
Lay out plan of Bayan 1 MHPP can be seen in Figures below

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Figure 1.Layout of Location Bayan 1
Figure 2. Birdview plan of Bayan 1
In three dimensions view, the lay out plan of Bayan 1 MHPP can be seen in Figure
below:
Improvement of acces
road, concrete cover of
1 m width, 900 m long
Rehabilitation canal 0f
87 m length from total
length of 890 m
Power house
Weir
Service
Area of
MHP
Headpond Existing
Existing
Headpond
Power house

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Figure 3.Component Activity of Bayan 1
Improvement of access road
This activity is an attempt to facilitate access to the location of the power house.The
existing will be covered with concrete of K 175, with size of 1x1 m, 8 cmthickness and
900 m length.
Waterway rehabilitation
This activity is an attempt to renovate the damage occur in the existing waterway. There
are several segments ofdamageobserved with the total length of 87 m. Clearly the
location of the damage can be seen in Fig.5 below.
Penstock: pipe
with dia 0.60 m,
47.4 m length
Headpond +
+547.20
Power House
+520,65 mdpl
Power House
Existing +522.5
mdpl
Spillway

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Figure 4.Waterway Improvement of Bayan 1
Head Pondand Spillway
Head pond is an ease pool with reinforced concrete construction with a length of 5.3 m,
a width of 2.4 m and a depth of 2.4 m (including he freeboard of 0.3m). Head pond
equipped with a spillway anda trash rack. The plan of the headpond can be seen in Fig.
6 below.

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Figure 5. Plan View of Headphone for Bayan 1
Section A-A
Figure 6. Long sectional of Headphone for Bayan 1
Figure 7. Headphone Bird View of Bayan 1
Headpond
Existing
New
Headpond

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Figure 8. 3D Viewof Headpond
Penstock
Penstock is a rapid pipe towards the turbine. Penstock is constructed of black stainless
steel with diameter of 60 cm, thickness of 100 mm and length of 47.4 m. To strengthen
the pipe position, concrete block buffers are used which is reinforced with steel ring. To
determine the expansion shrinkage in each pipe,the expansion joint is installed near the
concrete block. The penstock construction can be seen in Fig.9 below.
Spillway
Penstock
Trashrack
Intake gate

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Figure 9. Penstock View
Figure 10. 3D View of Penstock
Blacksteel dia.
60 cm, 52 m
length
Saddle
Support
Concrete bock

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Power House
Power House is a building covered by roof,for the operation of the turbine and control
panel. The building can be categorized as ordinary construction but the turbine and
generator inside the building must be designed with a foundation separated from the
building.The size of the power house is 7x5 m2
, with plastered brick wall, rolling door,
ceramic flooring, roofing spandex with steel frame. The detail of the power house can be
seen in Fig. 11 and Fig. 12 below.
Figure 11. Power House Plan of Bayan 1
Figure 12. 3D View of Power House

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Excavation and Backfill at the Main Civil Components
The works of excavation and backfilling at Bayan-1 MHPP are presented in the Table
below.
Table 2. Work of excavation and backfilling
No
Excavated material
Planned Use
Source Excavation
Method
Estimated
Volume
(m3
)
1 Access road With heavy
equipment
(excavator)
270 The selected material is used for backfilling the
access road on segments which need backfill.
The requirement of backfill material is 370 m3
.
2 Waterway With hoe,
shovel,
crowbar,
etc
43.5 The selected material is used for backfilling the
waterway on segments which need backfill. The
requirement of backfill material for waterway is
22.75 m3
. The excess material (20.75 m3
) is used
for backfilling the access road.
3 Headpond With hoe,
shovel,
crowbar,
etc
headpond on structure components which need
backfill. The requirement of backfill material for
headpond is 62.00 m3
.
The excess material (25.92 m3
) is used for
backfilling the access road.
4 Penstock With hoe,
shovel,
crowbar,
etc
access road
5 Power house
foundation
With hoe,
shovel,
crowbar,
etc
power house building, i.e. to elevate the floor of
powerhouse building from the original ground
elevation. The requirement of backfill material is
23.45 m3
. The excess material (3.64 m3
) is
disposed at a place near power house
6 Tail race With hoe,
shovel,
crowbar,
etc
13.05 The selected material is used for backfilling of
tailrace parts which need backfill. The
requirement is 3.26 m3
. The excess material (9.79
m3
) is used for backfilling the access road

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SURVEY AND INVESTIGATION
AT LOCATIONS OF CIVIL STRUCTURES
1. TOPOGRAPHY SURVEY
A. Aims of Survey
The aim of this survey is to gather data to produce a topographic map showing
theconfiguration of the terrain and the location of natural and man-made objects.
To describe or establish the positions of points on the surface ofthe earth,
cartesian coordinates is used to provide an address for the point.
B. Results of Topography Survey
The results of topographysurvey at the location of main civil components are
shown in the following figures.

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Figure 13. Map of topography and existing condition at Bayan 1 MHPP location

17
2. SOIL INVESTIGATION
3 (three) kinds of soil investigation, i.e drilling including Standard Penetration
Test (SPT), Geoelectrical surveyand Cone Penetrometer Test (CPT),have been
conducted at the site of the Bayan 1MHPP for the analysis formain civil
structures.
A. Drilling and SPT
The drilling program (core drilling and SPT) was conducted during the date of 2-4
April 2016 at the design location of power house. This drilling investigation is
aimed to obtain field soil and rock data, then to test samples gained from the test.
The data will therefore be used for calculating the bearing capacity of the soils.
Rotary drilling method was applied to investigate the soils dan rocks at site, and
during the drilling the standard penetration tests were also conducted to obtain
the N values of the soils of each 2 m depth. Test pit dan trech were also
conducted to provide more soil data at the site.
The results of drilling at the location of power house can be seen in the following
table and figure.
Table 3. Lithology at the location of power house of Bayan 1 MHP
Depth (m) Lithology
Number of impacts
N/30
Conmpaction
0.00 – 2.00 Silty gravel sand
2.00 – 4.00 Silty gravel sand 2 Very low
4.00 – 6.00 Breccia > 50 Very dense
> 10.00 Breccia > 50 Very dense

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Figure 14. Results of drilling log of soil investigation

19
B. Geoelectrical Survey
The objectives of this survey are:
 To predict the subsurface geological layers by means of resistivity
distribution by making measurements on the ground surface.
 To know the suitability of constructing components of micro hydro power
plan in the study location.
The survey was done by making two-dimensional survey in 6 cross-sectional
lines, starting from the upstream of the designed headpond to the downstream of
the designed tailrace (the following Figure).
Table 4. Coordinates of the lines survey
Line
Left side Right side
X Y X Y
Line 1 435757.32 9081879.62 435734.77 9081841.01
Line 2 435767.44 9081874.09 435745.94 9081836.08
Line 3 435777.78 9081866.40 435757.03 9081830.94
Line 4 4357887.70 9081859.03 435767.41 9081824.93
Line 5 435802.47 9081850.90 435782.48 9081816.20
Line 6 435820.35 9081843.99 435794.19 9081806.05
Based on the resistivity values obtained from the measurement, prediction of
subsurface geological layers is based on criteria shown in the following Figure 16
and Table 5 in the next page.

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Figure 15. Location of geoelectrical survey in Bayan 1 MHP

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Figure 16. The resistivity and conductivity of rocks, soils and minerals (Loke M.,H, 2004)
Table 5. The resistivity and conductivity of rocks, soils and minerals (Loke M.,H, 2001)
Material
Resistivity
(Ohm-m)
Conductivity (Siemen/m)
Granite 5000 – 10
6
10
-6
– 2x10
-4
Basalt 1000 – 10
6
10
-6
– 2x10
-3
Slate 600 – 4x10
7
2.5x10
-8
– 1.7x10
-3
Marble 100 – 2.5x10
8
4x10
-9
–10
-2
Quartzite 100 – 2x10
8
5x10
-9
–10
-2
Sandstone 8 – 4000 2.5x10
-4
– 0.125
Shale 20 – 2000 5x10
-4
– 0.05
Limestone 50 – 400 2.5x10
-3
– 0.02
Clay 1 – 100 0.01 – 1
Aluvium 10 – 800 1.25x10
-3
– 0.1
Groundwater 10 – 100 0.01 – 0.1
Salt water 0.2 5
Data obtained from the survey was then process by using RES2DINV software.
Inversion was done by using least-squares inversion method. Results are shown in the
figures below.

22
Table 6. Values obtained from measurement at Bayan 1, Line 1, first measurement.
Datum n Axis A M N B SP I:AB V:MN Time
1 1 1 1 2 3 4 0.0427 0.1328 0.4600 9:09:51 AM
2 1 2 2 3 4 5 0.4510 0.1310 0.7720 9:10:01 AM
3 1 3 3 4 5 6 0.1975 0.1331 0.7590 9:10:11 AM
4 1 4 4 5 6 7 0.0385 0.1328 0.3576 9:10:21 AM
5 1 5 5 6 7 8 0.0642 0.1330 0.4310 9:10:31 AM
6 1 6 6 7 8 9 0.0867 0.1330 0.2995 9:10:42 AM
7 1 7 7 8 9 10 0.0759 0.1327 2.0520 9:10:52 AM
8 1 8 8 9 10 11 0.0670 0.1327 0.6720 9:11:03 AM
9 1 9 9 10 11 12 0.1261 0.1326 1.0770 9:11:14 AM
10 1 10 10 11 12 13 0.1431 0.1327 1.3550 9:11:24 AM
11 1 11 11 12 13 14 0.0808 0.1324 1.1320 9:11:34 AM
12 1 12 12 13 14 15 0.0019 0.1325 0.9490 9:11:44 AM
13 1 13 13 14 15 16 0.1555 0.1320 0.8180 9:11:53 AM
14 2 1 1 3 4 6 0.2299 0.1326 0.1102 9:12:04 AM
15 2 2 2 4 5 7 0.0937 0.1304 0.3350 9:12:14 AM
16 2 3 3 5 6 8 0.3620 0.1327 0.5590 9:12:24 AM
17 2 4 4 6 7 9 0.0562 0.1326 0.1383 9:12:35 AM
18 2 5 5 7 8 10 0.0430 0.1326 0.1372 9:12:45 AM
19 2 6 6 8 9 11 0.0389 0.1326 1.3450 9:12:55 AM
20 2 7 7 9 10 12 0.0818 0.1322 0.2926 9:13:06 AM
21 2 8 8 10 11 13 0.0383 0.1324 0.2250 9:13:16 AM
22 2 9 9 11 12 14 0.0337 0.1322 0.5640 9:13:27 AM
23 2 10 10 12 13 15 0.0421 0.1323 0.5510 9:13:37 AM
24 2 11 11 13 14 16 0.2474 0.1317 0.6160 9:13:47 AM
25 3 1 1 4 5 8 0.0097 0.1322 0.1269 9:13:57 AM
26 3 2 2 5 6 9 0.0658 0.1304 0.0028 9:14:08 AM

23
Table 6. Values obtained from measurement at Bayan 1, Line 1, first measurement (Continued)
Datum Depth Axis A M N B SP I:AB V:MN Time
27 3 3 3 6 7 10 0.1320 0.1324 0.1951 9:14:18 AM
28 3 4 4 7 8 11 0.3936 0.1324 0.4450 9:14:29 AM
29 3 5 5 8 9 12 0.0315 0.1322 0.9470 9:14:39 AM
30 3 6 6 9 10 13 0.0561 0.1324 0.1731 9:14:50 AM
31 3 7 7 10 11 14 0.0093 0.1318 0.1288 9:15:00 AM
32 3 8 8 11 12 15 0.1419 0.1322 0.3119 9:15:10 AM
33 3 9 9 12 13 16 0.0076 0.1317 0.3050 9:15:20 AM
34 4 1 1 5 6 10 0.0538 0.1320 0.0316 9:15:31 AM
35 4 2 2 6 7 11 0.0872 0.1298 0.1304 9:15:42 AM
36 4 3 3 7 8 12 0.0836 0.1321 0.0391 9:15:52 AM
37 4 4 4 8 9 13 0.1378 0.1322 0.5480 9:16:03 AM
38 4 5 5 9 10 14 0.8270 0.1321 0.9010 9:16:13 AM
39 4 6 6 10 11 15 0.0253 0.1323 0.0681 9:16:23 AM
40 4 7 7 11 12 16 0.1325 0.1314 0.2458 9:16:33 AM
41 5 1 1 6 7 12 0.0228 0.1318 0.0127 9:16:44 AM
42 5 2 2 7 8 13 0.2363 0.1301 0.2575 9:16:54 AM
43 5 3 3 8 9 14 0.1755 0.1319 0.3885 9:17:04 AM
44 5 4 4 9 10 15 0.6770 0.1321 0.7410 9:17:14 AM
45 5 5 5 10 11 16 0.0359 0.1317 0.0315 9:17:25 AM
46 6 1 1 7 8 14 0.0824 0.1318 0.0906 9:17:35 AM
47 6 2 2 8 9 15 0.1685 0.1298 0.2658 9:17:45 AM
48 6 3 3 9 10 16 0.6180 0.1316 0.6610 9:17:56 AM
49 7 1 1 8 9 16 0.1625 0.1314 0.0336 9:18:06 AM

24
Table 7. Comparation between three measurements in the same line measurement, Line 1 in Bayan 1 Teres Genit
1st
Measurement 2nd
Measurement 3rd
Measurement Error 2nd
to 1st
Error 3rd
to 1st
Datum I:AB V:MN I:AB V:MN I:AB V:MN Current Voltage Current Voltage
1 0.1328 0.46 0.1318 0.611 0.1302 0.6090 0.0000 0.0228 0.0000 0.0222
2 0.131 0.772 0.1302 0.584 0.1284 0.5470 0.0000 0.0353 0.0000 0.0506
3 0.1331 0.759 0.1323 0.65 0.1307 0.6620 0.0000 0.0119 0.0000 0.0094
4 0.1328 0.3576 0.132 0.512 0.1304 0.5680 0.0000 0.0238 0.0000 0.0443
5 0.133 0.431 0.1321 0.481 0.1306 0.4760 0.0000 0.0025 0.0000 0.0020
6 0.133 0.2995 0.1322 0.3684 0.1306 0.3821 0.0000 0.0047 0.0000 0.0068
7 0.1327 2.052 0.1318 2.069 0.1301 2.0470 0.0000 0.0003 0.0000 0.0000
8 0.1327 0.672 0.1319 0.926 0.1303 0.9530 0.0000 0.0645 0.0000 0.0790
9 0.1326 1.077 0.1319 0.968 0.1302 0.9240 0.0000 0.0119 0.0000 0.0234
10 0.1327 1.355 0.1319 1.476 0.1302 1.4900 0.0000 0.0146 0.0000 0.0182
11 0.1324 1.132 0.1316 1.063 0.1301 1.0020 0.0000 0.0048 0.0000 0.0169
12 0.1325 0.949 0.1317 1.082 0.1301 1.1400 0.0000 0.0177 0.0000 0.0365
13 0.132 0.818 0.1312 0.804 0.1296 0.8080 0.0000 0.0002 0.0000 0.0001
14 0.1326 0.1102 0.1319 0.1294 0.1303 0.1303 0.0000 0.0004 0.0000 0.0004
15 0.1304 0.335 0.1295 0.1915 0.1283 0.1920 0.0000 0.0206 0.0000 0.0204
16 0.1327 0.559 0.1321 0.663 0.1305 0.6300 0.0000 0.0108 0.0000 0.0050
. . . . . . . . . . .
. . . . . . . . . . .
. . . . . . . . . . .
48 0.1316 0.661 0.1301 0.771 0.1297 0.8240 0.0000 0.0121 0.0000 0.0266
49 0.1314 0.0336 0.1298 0.0504 0.1294 0.0710 0.0000 0.0003 0.0000 0.0014
Avrage 0.1320 0.4712 0.1309 0.4832 0.1299 0.4852
RMSE 0.0012 0.0839 0.0021 0.1004
Ratio RMSE to Average 1% 18% 2% 21%

25
Figure 17. Diagram of average resistivity in Bayan 1, Line 1 to Line 4. The vertical axis stands for depth measured from land surface

26
Figure 18. Diagram of average resistivity in Bayan 1, Line 4 to Line 6. The vertical axis stands for depth measured from land surface

27
Figure 19. Diagram of average conductivity in Bayan 1, Line 1 to Line 4. The vertical axis stands for depth measured from land surface

28
Figure 20. Diagram of average conductivity in Bayan 1, Line 4 to Line 6. The vertical axis stands for depth measured from land surface

29
Table 8. The average of resistivity and conductivity in Line 1, Bayan 1
X (m) Depth (m) Resistivity (Ohm. M) Conductivity (Siemen. m
-1
)
3 -0.5 72.62 0.01380
5 -0.5 26.96 0.03710
7 -0.5 22.08 0.04530
9 -0.5 16.79 0.05960
11 -0.5 13.95 0.07170
13 -0.5 24.00 0.04170
15 -0.5 370.50 0.00270
17 -0.5 40.64 0.02460
19 -0.5 26.99 0.03710
21 -0.5 80.35 0.01240
23 -0.5 174.68 0.00573
25 -0.5 221.50 0.00452
27 -0.5 85.20 0.01170
3 -1.5 28.24 0.03540
5 -1.5 288.32 0.00347
7 -1.5 98.65 0.01010
9 -1.5 29.39 0.03400
11 -1.5 71.68 0.01400
13 -1.5 57.27 0.01750
15 -1.5 120.27 0.00832
17 -1.5 558.41 0.00179
19 -1.5 432.81 0.00231
21 -1.5 318.63 0.00314
23 -1.5 50.45 0.01980
25 -1.5 129.65 0.00771
27 -1.5 23.46 0.04260
5 -2.55 54.17 0.01850
7 -2.55 97.59 0.01020
9 -2.55 55.57 0.01800
11 -2.55 118.83 0.00842
13 -2.55 114.79 0.00871
15 -2.55 371.55 0.00269
17 -2.55 3510.20 0.00029
19 -2.55 3710.50 0.00027
21 -2.55 857.84 0.00117
23 -2.55 60.56 0.01650
25 -2.55 25.54 0.03920
7 -3.7 26.57 0.03760
9 -3.7 31.26 0.03200
11 -3.7 52.43 0.01910
13 -3.7 100.71 0.00993
15 -3.7 569.62 0.00176
17 -3.7 4461.60 0.00022
19 -3.7 4425.40 0.00023
21 -3.7 715.79 0.00140
23 -3.7 49.56 0.02020
9 -4.98 7.55 0.13240
11 -4.98 12.12 0.08250
13 -4.98 46.93 0.02130
15 -4.98 314.42 0.00318
17 -4.98 1709.80 0.00059
19 -4.98 1276.10 0.00078
21 -4.98 227.66 0.00439
11 -6.37 1.64 0.61120
13 -6.37 18.86 0.05300
15 -6.37 142.57 0.00701
17 -6.37 640.28 0.00156
19 -6.37 266.12 0.00376

30
-1
)
3 -0.5 244.41 0.004091
5 -0.5 79.32 0.0126
7 -0.5 113.36 0.008821
9 -0.5 55.91 0.0179
11 -0.5 25.25 0.0396
13 -0.5 40.37 0.0248
15 -0.5 8492 0.000118
17 -0.5 182.21 0.005488
19 -0.5 263.96 0.003788
21 -0.5 173.13 0.005776
23 -0.5 164.12 0.006093
25 -0.5 345.23 0.002897
27 -0.5 122.55 0.00816
3 -1.5 78.95 0.0127
5 -1.5 30.41 0.0329
7 -1.5 60.04 0.0167
9 -1.5 27.51 0.0364
11 -1.5 134.4 0.00744
13 -1.5 132.04 0.007573
15 -1.5 391.61 0.002554
17 -1.5 2252.8 0.000444
19 -1.5 78.16 0.0128
21 -1.5 253.28 0.003948
23 -1.5 185.65 0.005386
25 -1.5 202.81 0.004931
27 -1.5 67.91 0.0147
5 -2.55 25.4 0.0394
7 -2.55 23.82 0.042
9 -2.55 33.05 0.0303
11 -2.55 224.41 0.004456
13 -2.55 90.08 0.0111
15 -2.55 41.84 0.0239
17 -2.55 959.38 0.001042
19 -2.55 174.96 0.005716
21 -2.55 179.44 0.005573
23 -2.55 119.13 0.008394
25 -2.55 67.59 0.0148
7 -3.7 22.97 0.0435
9 -3.7 43.46 0.023
11 -3.7 142.12 0.007036
13 -3.7 56.42 0.0177
15 -3.7 30.24 0.0331
17 -3.7 316.42 0.00316
19 -3.7 209.86 0.004765
21 -3.7 121.6 0.008224
23 -3.7 60.19 0.0166
9 -4.98 51.8 0.0193
11 -4.98 99.98 0.01
13 -4.98 57.58 0.0174
15 -4.98 48.04 0.0208
17 -4.98 180.14 0.005551
19 -4.98 172.08 0.005811
21 -4.98 84.25 0.0119
11 -6.37 111.3 0.008985
13 -6.37 72.74 0.0137
15 -6.37 73.6 0.0136
17 -6.37 163.97 0.006099
19 -6.37 144.29 0.00693

31
-1
)
3 -0.5 513.96 0.001946
5 -0.5 368.38 0.002715
7 -0.5 262.49 0.00381
9 -0.5 306.99 0.003257
11 -0.5 98.96 0.0101
13 -0.5 142.88 0.006999
15 -0.5 249.47 0.004008
17 -0.5 198 0.005051
19 -0.5 1277.5 0.000783
21 -0.5 307.14 0.003256
23 -0.5 556.33 0.001797
25 -0.5 797.62 0.001254
27 -0.5 354.55 0.00282
3 -1.5 82.01 0.0122
5 -1.5 2877.1 0.000348
7 -1.5 2807.7 0.000356
9 -1.5 293.33 0.003409
11 -1.5 1186.7 0.000843
13 -1.5 106.74 0.009369
15 -1.5 37.96 0.0263
17 -1.5 109.99 0.009092
19 -1.5 105.09 0.009516
21 -1.5 172.19 0.005808
23 -1.5 202.34 0.004942
25 -1.5 151.16 0.006616
27 -1.5 425.56 0.00235
5 -2.55 603.64 0.001657
7 -2.55 1911.6 0.000523
9 -2.55 185.39 0.005394
11 -2.55 276.36 0.003618
13 -2.55 44.08 0.0227
15 -2.55 23.96 0.0417
17 -2.55 295.84 0.00338
19 -2.55 160.92 0.006214
21 -2.55 129.97 0.007694
23 -2.55 115.76 0.008639
25 -2.55 269.74 0.003707
7 -3.7 519.29 0.001926
9 -3.7 165.44 0.006044
11 -3.7 127.02 0.007873
13 -3.7 46.21 0.0216
15 -3.7 49.18 0.0203
17 -3.7 576.05 0.001736
19 -3.7 808.46 0.001237
21 -3.7 510.3 0.00196
23 -3.7 459.73 0.002175
9 -4.98 202.09 0.004948
11 -4.98 142.62 0.007012
13 -4.98 89.32 0.0112
15 -4.98 141.26 0.007079
17 -4.98 1249.2 0.000801
19 -4.98 5419.8 0.000185
21 -4.98 3641.5 0.000275
11 -6.37 203.04 0.004925
13 -6.37 155.65 0.006425
15 -6.37 299.37 0.00334
17 -6.37 2980 0.000336
19 -6.37 72181.1 0.00001385

32
-1
)
3 -0.5 379.14 0.002638
5 -0.5 240.61 0.004156
7 -0.5 121.55 0.008227
9 -0.5 494.9 0.002021
11 -0.5 645.43 0.001549
13 -0.5 667.17 0.001499
15 -0.5 230.63 0.004336
17 -0.5 63.15 0.0158
19 -0.5 561.75 0.00178
21 -0.5 159.98 0.006251
23 -0.5 322.85 0.003097
25 -0.5 128.24 0.007798
27 -0.5 236.54 0.004228
3 -1.5 323.56 0.003091
5 -1.5 2639.1 0.000379
7 -1.5 2724.1 0.000367
9 -1.5 10692.6 0.00009352
11 -1.5 1246.9 0.000802
13 -1.5 32.67 0.0306
15 -1.5 1131.9 0.000883
17 -1.5 216.53 0.004618
19 -1.5 846.93 0.001181
21 -1.5 1438.5 0.000695
23 -1.5 38.88 0.0257
25 -1.5 213.25 0.004689
27 -1.5 1595.3 0.000627
5 -2.55 256.79 0.003894
7 -2.55 1055 0.000948
9 -2.55 1685.3 0.000593
11 -2.55 220.73 0.00453
13 -2.55 16 0.0625
15 -2.55 1333.4 0.00075
17 -2.55 2008.7 0.000498
19 -2.55 2535.2 0.000394
21 -2.55 1713.3 0.000584
23 -2.55 167.84 0.005958
25 -2.55 769.53 0.001299
7 -3.7 86.15 0.0116
9 -3.7 103.56 0.009656
11 -3.7 28.11 0.0356
13 -3.7 16.15 0.0619
15 -3.7 690.13 0.001449
17 -3.7 3470 0.000288
19 -3.7 3443 0.00029
21 -3.7 1488.2 0.000672
23 -3.7 549.86 0.001819
9 -4.98 11.76 0.085
11 -4.98 6.44 0.1553
13 -4.98 15.26 0.0655
15 -4.98 308.85 0.003238
17 -4.98 2114.2 0.000473
19 -4.98 2515.7 0.000398
21 -4.98 1113.5 0.000898
11 -6.37 1.49 0.6711
13 -6.37 11.34 0.0882
15 -6.37 189.24 0.005284
17 -6.37 1389 0.00072
19 -6.37 1942.3 0.000515

33
-1
)
3 -0.5 296.48 0.003373
5 -0.5 790.19 0.001266
7 -0.5 396.83 0.00252
9 -0.5 282.81 0.003536
11 -0.5 222.59 0.004493
13 -0.5 185.25 0.005398
15 -0.5 638.95 0.001565
17 -0.5 290.86 0.003438
19 -0.5 426.54 0.002344
21 -0.5 330.3 0.003028
23 -0.5 95.42 0.0105
25 -0.5 124.02 0.008063
27 -0.5 152.32 0.006565
3 -1.5 457.84 0.002184
5 -1.5 424.2 0.002357
7 -1.5 1047.4 0.000955
9 -1.5 219.91 0.004547
11 -1.5 391.71 0.002553
13 -1.5 2343.3 0.000427
15 -1.5 54.48 0.0184
17 -1.5 2238.5 0.000447
19 -1.5 1.39 0.7179
21 -1.5 1543.8 0.000648
23 -1.5 1374.3 0.000728
25 -1.5 301.45 0.003317
27 -1.5 377.57 0.002649
5 -2.55 334.3 0.002991
7 -2.55 680.96 0.001469
9 -2.55 211.1 0.004737
11 -2.55 272.8 0.003666
13 -2.55 513.37 0.001948
15 -2.55 41.19 0.0243
17 -2.55 313.22 0.003193
19 -2.55 10.47 0.0955
21 -2.55 1482 0.000675
23 -2.55 2716.1 0.000368
25 -2.55 1030.6 0.00097
7 -3.7 280.6 0.003564
9 -3.7 200.78 0.004981
11 -3.7 228.19 0.004382
13 -3.7 228.82 0.00437
15 -3.7 76.04 0.0132
17 -3.7 185.68 0.005386
19 -3.7 139.48 0.007169
21 -3.7 1842.5 0.000543
23 -3.7 3126.3 0.00032
9 -4.98 258.3 0.003871
11 -4.98 306.48 0.003263
13 -4.98 262.5 0.00381
15 -4.98 183.55 0.005448
17 -4.98 373.9 0.002675
19 -4.98 1086.9 0.00092
21 -4.98 4041.4 0.000247
11 -6.37 566.81 0.001764
13 -6.37 387.88 0.002578
15 -6.37 362.03 0.002762
17 -6.37 880.04 0.001136
19 -6.37 7450.4 0.000134

34
-1
)
3 -0.5 440.53 0.00227
5 -0.5 276.55 0.003616
7 -0.5 242.55 0.004123
9 -0.5 236.62 0.004226
11 -0.5 1167 0.000857
13 -0.5 796.05 0.001256
15 -0.5 59.26 0.0169
17 -0.5 312 0.003205
19 -0.5 278.02 0.003597
21 -0.5 261.98 0.003817
23 -0.5 718.91 0.001391
25 -0.5 301.61 0.003316
27 -0.5 106.78 0.009365
3 -1.5 232 0.00431
5 -1.5 11186.1 0.0000894
7 -1.5 84068.9 0.0000119
9 -1.5 137.92 0.007251
11 -1.5 809.05 0.001236
13 -1.5 103.17 0.009693
15 -1.5 109.55 0.009128
17 -1.5 259.97 0.003847
19 -1.5 15.55 0.0643
21 -1.5 399.38 0.002504
23 -1.5 31.41 0.0318
25 -1.5 205.35 0.00487
27 -1.5 381.73 0.00262
5 -2.55 972.99 0.001028
7 -2.55 5271.2 0.00019
9 -2.55 101.2 0.009881
11 -2.55 148.52 0.006733
13 -2.55 172.44 0.005799
15 -2.55 839.82 0.001191
17 -2.55 587.83 0.001701
19 -2.55 42.33 0.0236
21 -2.55 89.5 0.0112
23 -2.55 39.16 0.0255
25 -2.55 313.55 0.003189
7 -3.7 276.72 0.003614
9 -3.7 71.04 0.0141
11 -3.7 75.84 0.0132
13 -3.7 224.62 0.004452
15 -3.7 1151.3 0.000869
17 -3.7 933.55 0.001071
19 -3.7 218.56 0.004575
21 -3.7 181.59 0.005507
23 -3.7 232.33 0.004304
9 -4.98 28.37 0.0352
11 -4.98 50.11 0.02
13 -4.98 207.99 0.004808
15 -4.98 794.03 0.001259
17 -4.98 1066.7 0.000937
19 -4.98 1089.7 0.000918
21 -4.98 905.13 0.001105
11 -6.37 6.15 0.1627
13 -6.37 143.98 0.006945
15 -6.37 619.77 0.001614
17 -6.37 1517 0.000659
19 -6.37 18533.8 0.00005396

35
C. Cone Penetrometer Test (CPT)
The CPT was applied to determine the geotechnical engineering properties of soils
and delineating soil stratigraphy. The test method consists of pushing an
instrumented cone, with the tip facing down, into the ground at a controlled rate
(controlled between 1.5-2.5 cm/s accepted). The resolution of the CPT in delineating
stratigraphic layers is related to the size of the cone tip, with typical cone tips having
a cross-sectional area of either 10 or 15 cm², corresponding to diameters of 3.6 and
4.4 cm.
CPT test has been conducted on 30 July 2016 at the site of the Bayan 1MHP, i.e. at
three locations of MHP components: headpond, penstock and power house.
Theselocations of three CPT test points can be seen in the Table below:
Table 14. Locations of test points at Bayan 1 (Teres Genit) MHP Project
No Nama Bangunan Code Cooordinate
1 Headpond S- 01 X= 435 757 ; Y = 9 081 819
2 Penstock S- 02 X= 435 780 ; Y = 9 081 814
3 Power House S- 03 X= 435 809 ; Y = 9 081 808
1) At location of headpond (S-01)
The results of bearing capacity analysis at the location of headpond (S-01) are
resumed in Table below.
Table 15. Results of CPT test at the location of headpond

36
2) At location of penstock (S-02)
At the designed location of penstock (S-02), the CPT was conducted until the depth
of 0.4m. At this layer, the unit contains silty clay. The conus resistance (qc) of > 250
kg/cm2
was reached at this depth. Below the depth of 0.4m, the unit contains gravel
and boulder andesit with diameter up to 50cm, and rounded andesit. The material
compaction is categorized as very dense. The results of bearing capacity analysis at
the location of penstock (S-02) are resumed in Table below.
Table 16. Results of CPT test at the location of penstock
3) At location of power house (S-03)
At S03 as the designed location of power house, the CPT was conducted until the
depth of 0.6m. At this layer, the unit contains silty clay. The conus resistance (qc) of
> 250 kg/cm2 was reached at this depth. Below the depth of 0.6m, the unit contains
gravel and boulder andesit with diameter up to 50cm, and rounded andesit. The
material compaction is categorized as very dense.

37
Figure 21. The soil condition at the location of power house (S-03) at the depth of 0.6m

38
DESIGN CRITERIA
1. PLANNING
A. Data and Reference to Consider for Planning
Hydrograph shows how flow varies throughout the year and how many months in a
year that a certain flow is exceeded. This same information is also presented in a
„Flow Duration Curve‟ for the stream. The hydrograph is converted to flow duration
curve simply by taking all the flow records over many years and placing them with the
highest figures on the left and the lower figure placed progressively over to the right.
The flow duration curve is useful because the power that could be generated can be
superimposed onto it so that it is possible to calculate the time in a year that certain
power levels can be obtained. This is also a planning tool to determine the size of
turbine to be installed indicating the required variable flow performance of turbine and
the plant factor constraints which will result from any particular choice of turbine size.
B. Selection of Locations for Main Civil Structures
1) Location of Intake
The location of the intake is selected considering the conditions described below.
Extreme care must be taken in this selection for the development of small-scale
hydropower as the cost of the intake facilities significantly determines the
development project economy.
a. River Channel Alignment
For small-scale and run-of-river types of hydropower plant, the appropriate
section within the river channel to construct the intake structure is where the
channel is as straight as possible in order to ensure steady and smooth flow of
water to the intake and also to prevent scouring of the river banks downstream
of the intake site.

39
b. Stability of Hillside Slope
The presence of a landslide or unsteady slope near an intake weir site causes
concerns for possible obstruction at the water intake by sediments from the
landslide or erosion. Sufficient consideration should, therefore, be given to the
stability of nearby hillsides as part of the intake location selection process.
c. Use of existing civil structures
In small-scale hydropower development, the use of existing civil structures
such as intake facilities for agriculture and irrigation channels, etc. can
contribute to the reduction of the development cost. Careful consideration
should, therefore, be given to the selection of the intake location so that such
civil structures already in place can be used.
d. Use of natural topographical features
The use of naturally formed pool for water intake will not only help in the cost
reduction but also conserving the waterfront environment, including the
riverside landscape and riparian ecosystem. When the use of natural
topographical features is planned, proper analysis of the following concerns
should be considered:
Preservation of the natural pool
Removal method of sedimentation
e. Intake Volume and Flood Water Level
In general, an intake weir is located at a narrow section of a river to reduce the
construction cost of the main body of the intake weir. However, it must be
noted that the selection of such a narrow section is not necessarily
advantageous for a small-scale hydropower plant because of the following
reasons.
In the case of the Tyrolean-type intake method, the length in the cross-
sectional direction must match the anticipated design discharge.
(0.1m3/s of inflow water per 1m of intake length)
When a weir is constructed at a narrow section, the flood water level at
the site inevitably becomes higher, necessitating an increased cross-
sectional area of the weir as well as an increased bank protection height
and length to ensure the stability of the weir.

40
f. Site Conditions for Settling Basin and Headrace, etc.
Select the preferable site for the settling basin, headrace and other structures
taking into consideration the conditions for the weir. It is also important to
carefully consider the topographical and geological conditions of the settling
basin site and headrace route.
g. Existence of River Water Use in Reduced Discharge Section
Water intake for agricultural or other purposes should be considered in the
survey in order that the use of river water for power generation will not affect
the present use of the river water.
h. Existing Features in Backwater Section
Existing features, such as roads and farmland, etc., in lower areas should also
be considered in the selection of the location of the intake weir to avoid
flooding. If the location of the intake weir is in a location which affects existing
features, the geographical area to be affected by backwater due to the
construction of the intake weir should be clarified by appropriate calculation. It
will also be necessary to construct river bank protections and drainage
structures to protect the existing facilities.
2) Headrace Route
a. Topography
A careful survey of the topography of the headrace route of a micro-
hydropower system is necessary since the headrace is usually an exposed
structure such as an open or covered channel. When an open channel is to be
constructed on a hillside, proper investigation as to the gradient or slope of the
headrace route must be done. If a valley or a ridge exists along the headrace
route, the actual route should be selected after examining the best route
(siphon for a valley section; open excavation or culvert for an elevated ridge
section).
b. Ground Stability
The ground stability of the headrace route must be carefully examined to avoid
incidents of loss of the waterway due to slope collapse in the case of the
ground-type (exposed) headrace.

41
c. Use of Existing Structures
It is advantageous to locate the headrace route along an existing road or
irrigation channel to reduce the cost, improve the workability and make it
relatively easy to evaluate the slope stability. However, the following concerns
must be taken into consideration for the use of existing structures:
 Maintenance of existing canal, road, drainage, etc.
 Ensure water quantity for irrigation and efficient water diversion method
3) Location of Head Tank
a. Topographical and geological conditions.The headtank is often located at a
ridge section and on a highly stable ground consisting of hard rock, etc. The
possibility of minimal excavation work, including that for the penstock, offers
favorable condition for selection of the site for headtank. However, it must be
noted that the location of the headtank at a ridge section is not appropriate
under the following conditions:
 The level of consolidation is generally low at the ridge section which is
located in a shallow area developed from advanced erosive dissection of
the valley.
 There will be larger fluctuations in the water level inside the tank which
will cause possible obstruction to the smooth flow of operation due to the
large volume of water required as the load changes. In such a case, it is
advisable to design a headtank with a bigger diameter that covers an
area wide enough to absorb load fluctuations. In this case, the desired
location for the headtank should be on a relatively flat area rather than
on a ridge section.
b. Ease of Dealing with Effluents
A spillway for a small-scale hydropower system may be omitted, however, if a
spillway for the headtank is introduced, the method of dealing with effluents
must be carefully examined. (There have been reports of the ground being
washed away because of the absence of a spillway for the excess water from
the headtank.). The installation of a spillway parallel to the penstock route
should not cause any major problems, however, the direct discharge of surplus
water and sediment inside the headtank to a nearby stream or hillside slope

42
requires careful examination of the discharge point. The profile as well as
cross-sectional alignment of the spillway are carefully designed to prevent
scouring of the nearby ground due to expected volume of water spillage.
The combined function of a settling basin and headtank will significantly help in
reducing of overall investment cost of micro-hydropower development.
Therefore, the possibility of introducing a combined headtank and settling
basin should be carefully examined at the planning stage.
4) Penstock Route
The penstock route should be selected considering the following parameters:
a. Hydraulic gradient
b. Topography of the penstock route
c. Ground stability of the penstock route
d. Use of existing infrastructures like roads, irrigation canals and others
The parameters to note for the selection of the penstock route are basically the
same as those for the selection of the headrace route but its relationship with the
hydraulic gradient must be carefully analyzed.
The penstock route must be designed to ensure safety vis-à-vis specific internal
as well as external pressures and that the profile of the penstock route must be
below the minimum hydraulic gradient line, i.e. minimum pressure line.
This minimum pressure line is determined by taking the internal pressure
fluctuation in the penstock at the time of rapid load shut-down into consideration.
The range of pressure fluctuation is larger in the downstream because it is
influenced by changes of the discharge at the turbine over time. Therefore,
careful attention is necessary at a site where the length of the penstock route is
long compared to the head.
Careful examination is also required in setting the location of the Francis turbine
with a slower specific speed as the range of pressure fluctuation can be widened
due to the abrupt control vane operation because of the increasing revolution
(speed) even at longer closure time of the control vane.
For other turbines, closing speed of the control vane is almost in proportion to the
speed of discharge reduction, however, no special problem occurs provided that
an adequate closure time is set.

43
5) Location of Powerhouse
The selection of the powerhouse location should consider the following conditions
in:
a. Accessibility
It is desirable for the powerhouse to be located at a site with easy access for
operation and maintenance purposes.
b. Conditions of the Foundation
The foundations of the powerhouse must be strong enough to withstand the
installation of heavy loads like the electro-mechanical equipment. For a micro-
hydropower plant, a compacted gravel layer may be sufficient because of the
relatively lightweight equipment (approximately 2 – 3 tons/m2).
c. Flood Water Level
The location of the powerhouse must avoid the level and section where the
water flows to avoid scouring and to prevent inundation of the powerhouse
during high flows. A small-scale hydropower station is planned for a small river
in a mountainous area where the flood stage is not recorded or established. In
this case, the flood water level could be assumed based on the information
listed below that could be used in the determination of the ground elevation of
the powerhouse with sufficient margin:
 Information obtained from local residents
 Ground elevation of nearby structures (roads, embankments and
bridges, etc.)
 Traces of flooding and vegetation boundary
d. Installation Conditions for Auxiliary Facilities
Space for the installation of an outdoor substation is required near the
powerhouse and the site must be selected in consideration to the possible
extension and the direction of the transmission line. However, when the
transmission voltage is the same as the generating voltage, the size of the
required space is small. Accordingly, the space created by the construction of
the foundations for the powerhouse is often sufficient to accommodate such
auxiliary facilities

44
6) Location of Tailrace
The location of the tailrace is determined using the same conditions as the
powerhouse location because it is located adjacent to the powerhouse. In other
cases, the location of the tailrace is decided by taking the following items into
consideration.
a. Flood Water Level
The tailrace channel should be preferably placed above the expected flood
water level. When the base elevation of the tailrace is planned to be lower than
the flood level, the location and base elevation of the tailrace must be decided
in consideration of (i) suitable measures to deal with the inundation or seepage
of water into the powerhouse due to flooding and (ii) a method to remove
sediment which may occur in the tailrace canal.
b. Existence of Riverbed Fluctuation at Tailrace
When riverbed fluctuation is expected to take place in the future, the location
of the water outlet must be selected so as to avoid any trouble to its operation
due to sedimentation in front of the tailrace.
c. Possibility of Scouring
Careful attention must be made to avoid the scouring of the riverbed and
nearby ground. The selection of a location where protective measures can be
easily applied is essential.
d. Flow Direction of River Water
The tailrace must be directed (in principle, facing downstream) so as not to
disrupt the smooth flow of the river water or a location which allows the
direction of the tailrace as that of the river flow should be selected.
2. DESIGN FOR CIVIL STRUCTURES
A. Weir Height Calculation
The weir volume is proportionate to the square of the height, it is important to
decide the weir height taking the following conditions into consideration.
a. Conditions restricting waterway elevation
To decide for the weir height, it is necessary to take the topographical and
geological conditions of the waterway route into consideration in addition to the

45
conditions at the weir construction site. Careful examination is necessary at
the site where the construction cost accounts for a large portion of the total
construction cost. In case the waterway is to be constructed along an existing
road, the weir height is often planned with reference to the elevation of the
road
b. Possibility of riverbed rise in downstream
Since the weir height for a small-scale hydropower plant is generally low, there
is possibility that its normal function could be disrupted by a rise of the riverbed
in the downstream. Accordingly, the future riverbed rise should be considered
in the selection of the weir height if the planned site falls under any of the
following cases:
Gently sloping river with a high level of transported sediment
Existence of not fully filled check dam, etc. in the downstream of the
planned intake weir
Presence of erosion in the downstream with possibility of continuous
erosion in the future
Existence of a narrow section in the downstream which obstructs the
flow of sediment and/or driftwood
c. Conditions to remove sediment from upstream of the weir and settling basin by
intake method
Under normal circumstances, the weir height should be planned to exceed the
calculatedvalue by the following method to ensure the smooth removal of
sediment from theupstream of the weir and the settling basin.
d. Influence on electric energy generated
At a site where the usable head is small or where it is planned to secure the
necessary head by a weir, the weir height significantly influences the level of
generated electric energy. Accordingly, it is necessary to determine the weir
height at a site by comparing the expected changes of both the construction
cost and the generated electric energy because of different weir heights.
e. Influence of back water
When roads, residential land, farmland and bridges, etc. exist in a lower
elevation area in the upstream of a planned intake weir site, it is necessary to
determine the weir height to prevent flooding due to back water. Particularly at
a site with a high weir height, the degree of influence on the above features
must be checked by means of back water calculation or other methods

46
B. Intake
a. Dimensions of Intake
In the design of intake dimension, the following matters should be considered.
- The dimension of the intake should be designed that the velocity of
inflow atthe intake is 0.5-1.0 m/s. If the velocity is too slow, the
dimension of intakebecome big. In this cake, excess inflow also
becomes big. On the other hand, if the velocity is too fast, the inflow
became unstable andthe head loss is relatively big.
- The ceiling of the intake should be designed with allowance of 10-
20cmfrom the water surface. The allowance should be obtained for
stable inflow.
- The height and the area of intake should be designed with the minimum
size
b. Important Points for Intake Design
For the design of the intake for a small-scale hydropower plant, it is necessary
to examine the possible omission of an intake gate in order to achieve cost
reduction. In the case of a small-scale hydropower plant, the headrace is
usually an open channel, a covered channel or a closed conduit. When this
type of headrace is employed, it is essential to avoid inflow of excess water ,
which considerably exceeds the design discharge, as it will directly lead to the
destruction of the headrace.
Meanwhile, the use of an automatic control gate for a small-scale hydropower
plant results an increase in construction cost, a manual control is an option. In
the case of the intake facility for a small-scale hydropower plant being
constructed in a remote mountain area, a swift response to flooding is difficult.
The following method is, therefore, proposed to control the inflow at the time of
flooding without the use of a gate.
- Principle
This method intends the design of an intake which becomes an orifice with
a rise of the river water level due to flooding. The inflow volume in this case
is calculated by the formula below.
- Equipment outline
The important points for design are listed below:

47
 It is necessary for the intake to have a closed tap instead of an open
tap so that it becomes a pressure intake when the river water level
rises.
 The intake should be placed at a right angle to the river flow
direction wherever possible so that the head of the approaching
velocity at the time of flooding is minimized.
 As water inflow at the time of flooding exceeds the design discharge,
the spillway capacity at the settling basin or starting point of the
headrace should be fairly large.
C. Headrace
The size of cross section and slope should be determined in such a matter that
the required turbine discharge can be economically guided to the head tank.
Generally, the size of cross section is closely related to the slope. The slope of
headrace should be made gentler for reducing head loss (difference between
water level at intake and at head tank) but this cause a lower velocity and thus a
lager cross section. On the contrary, a steeper slope will create a higher velocity
and smaller section but also a lager head loss.
Generally, in the case of small-hydro scheme, the slope of headrace will be
determined as 1/500 – 1/1,500. However in the case of micro-hydro scheme, the
slope will be determined as 1/50 – 1/500, due to low skill on the survey of
levelling and construction by local contractor.
The cross section of headrace is determined by following method
AvQ
2
13
2
2
1
S
hb
hb
n
v
or
2
1
3
2
2
S
hb
hb
kv
hbS
hb
hb
n
Q 2
13
2
2
1
or
hbS
hb
hb
kQ 2
1
3
2
2
Where:
Q = flow rate (m3
.s-1
)
v = flow velocity (m. s-1
)

48
A = waterway cross sectional area (m2
)
n = Manning‟s coefficient
k = Strickler coefficient
b = width of cross sectional waterway (m),
h = water-depth in cross sectional waterway (m),
S = the sloop
D. Headtank
a. Headtank Capacity
The functions of headtank are roughly following 2 items : (1) Control difference
of discharge in a penstock and a headrace cause of load fluctuarion. And (2)
Finally remove litter (earth and sand, driftwood, etc.) in flowing water
Headtank capacity :
Vsc = As×dsc＝B×L×dsc
where,
As : area of headtank
B : width of headtank
L : length of headtank
Dsc : water depth from uniform flow depth of a headrace when
usingmaximum discharge (h0) to critical depth from top of a dike for
sandtrap in a headtank (hc)
The hydraulics of the head pond should be consideredto to ensure water
supply to the turbine generators.
Based on Pedoman Studi Kelayakan PLTMH (Ditjen Listrik dan Pemanfaatan
Energi, Departemen Energi dan Sumber Daya Mineral, Republik of Indonesia,
2009), there are some criterias on designing headpond
- The structure must be impermeable
- The structure can be made from concrete or stone masonry, the minimum
wall thickness is 25 cm
- The structure must be equipped with:
o smooth trashrack
o Spillway, with capacity 120% of design flow.The spillway must be
equipped with structure to reduce energy (stilling basin)

49
o Flushgate to flush the trapped sediment. Location of flushgate must be
separated from spillway
o Stepladder for maintenance and operation.
- Elevation of the upper part of the penstock pipe must be at least 2D lower
than water level with D is the diameter of penstock. The lower part of the
penstock must be at least 30 cm from the bottom of the headpond.
- Sediment must be designed therefore unable to enter to the penstock.
The headpond is constructed to store sufficient water to prevent large
fluctuations of the water level during turbine operation. The dimension of the
headpond was designed based on two references: (1) Based on experience.
As common known, width of headpond is designed as three time of the
waterway width, and the length of headpond is twice of its width. (2) Based on
Civil Works for Micro Hydro Power Units (University of Applied Sciences
Nortwestern Switzerland, 2009), the water volume should be around 60-100
times that of the designed turbine flow.
b. Important Points for Headtank Design
The design details for the headtank for a small-scale hydropower plant are
basically the same as those for a small to medium-scale hydropower plant and
the particularly important issues are discussed below.
1) Covering water depth and installation height of penstock inlet
As the penstock diameter is generally small in the case of a small-scale
hydropower plant, it should be sufficient to secure a covering water depth
which is equal to or larger than the inner diameter of the penstock.
2) Appropriate spacing of screen bars for turbine type, etc
The spacing of the screen bars (effective screen mesh size) is roughly
determined by the gate valve diameter but must be finalised in
consideration of the type and dimensions of the turbine and the quantity
as well as quality of the litter
3) Installation of vent pipe to complement headtank gate
When a headtank gate is installed instead of a gate valve for a power
station, it is necessary to install a vent pipe behind the headtank gate to
prevent the rupture of the penstock line. In this case, the following

50
empirical formula is proposed to determine the dimensions of the vent
pipe.
In this case, the following empirical formula is proposed to determine the
dimensions of the vent pipe.
d = 0.0068 (P2
.L /H2
) 0.273
Where,
d : inner diameter of the vent pipe (m)
P : rated output of the turbine (kW)
L : total length of the vent pipe (m)
H : head (m)
4) Spillway at the headtank
Generally, the spillway will be installed at the headtank in order to
release excess water is discharged to the river safely when the turbine
stopped it. Analysis is then performed by checking the depth occurred in
the spillway for 120% of design flow.The sizes of spillway are decided by
following equation
3
..2..
3
2
hgbCdQ
where :
Q = flow rate (m3
/s)
Cd = coeff. of flow rate (1.2)
b = width of spillway (m)
g = gravity constant (m2
/s)
h = water depth in the spillway crest (m)
E. Penstock
a. Penstock Material
At present, the main pipe materials for a penstock are steel, ductile iron and
FRPM (fibre reinforced plastic multi-unit). In the case of a small-scale
hydropower plant, the use of hard vinyl chloride, Howell or spiral welded pipes
can be considered because of the small diameter and relatively low internal
pressure.

51
The characteristics of steel pipe are popular choice to penstock at a
hydropower plant, reliable material due to established design techniques, and
No problem of water-tightness as the joint connection method is established.
b. Calculation of Steel Pipe Thickness
The minimum thickness of steel pipe of penstock is determined by following
formula
Where:
P : design hydraulic pressure, i.e. hydrostatic pressure + water
hammer (kgf/cm2
)
R : inside radius of penstock pipe
s : allowable stress of steel = 1,485 kg/cm2
Fs : safety factor = 1.2
f : welding efficiency = 0.9
Ca : additional thickness for the corrosion effect = 1.5 mm
c. Determining Diameter of Penstock
Generally the diameter of penstock is determined by comparison between the
cost of penstock and head loss at penstock. The diameter of penstock will be
determined by by the following formulas:
1) Based on Hydro Resources Inventory Study PLN, 1999:
D1 = 0,785 Q0,407
Where :
Q =Design discharge
2) Based on Reference of Hydropower Ilynich
D2 =
Where :
Q = discharge
H = Head
C = Allowable Corrosion= 1.5 mm ( 0.0015 m)
3) Based on Handbook of Applied Hydraulics page 536
D3 =
CaFs
f
RP
s
ot

52
Where:
D = penstock diameter (m)
P = power
H = effective high fall
d. Head losses
When channelling water from forebay tank to the turbine, losses occur
due to friction and otherobstacles within the penstock. Friction loss refers
to the portion of pressure lost by fluids while movingthrough a pipe.
Head loss due to the entrance
where :
f1 : Coefficient Bell-mouth entrance loss
: for a. Rounded inlet 0.1
b. Rectangular inlet 0.2
c. Square inlet0.5
Q : discharge m3
/sec
A : cross section of flow area after the inlet 0.25 x π x D2
(m2
)
g : acceleration of gravity = 9.81m/sec2
v : velocity at penstock after the inlet (m/sec)
Energy Loss due to trashrack existence
h2 =
Where :
b : shape coefficients of trash racks
: for square = 2.42
round = 1.79
q : slope of trash rack
t : Thickness of the trashrack rod
b : Interval of the trashrack rod
v : Flow velocity in front of trashrack = 1.20 m/sec
Energy loss due to the friction

53
V = 0,8492 CR0,63
S0,54
where :
f3 : Coefficient of friction
v : Flow velocity (m / s)
D : penstock diameter (m)
L : Channel length (m)
R : radius hydraulic (m)
A : cross section of flow area (m)
C : Material roughness for steel = 130 (coeff. of hazen wiliam
g : Acceleration of gravity = 9.81 m/sec2
Q : discharge
Energy loss due to the bend
Where :
f4 : Coefficient loss at the bend: FB1 x fb2
fb1 : Coefficient of the ratio of bend curve
:
D : penstock diameter (m)
P : The radius of pipe bend (m)
fb2 : Coefficient of bend =
q : Angle of bend curve
v : Flow velocity (m / s)
Energy loss due to the pipe branch
Where:
f5 : Coefficient of energy loss due to the pipe branch (obtained
from Gardel graph) : depends on the ratio of diameter of
main pipe and branch pipe = (D/d)
: depends on the ratio of discharge flowing in the main pipe
and branch pipe=(Q/q)
V : Flow velocity in the branch pipe (m/sec)

54
Energy loss due to the pipe enlargement and pipe contraction
Where
f6 : Due to the pipe contraction
A2 : cross-sectional area of the smaller pipe (m 2)
A1 : cross-sectional area of the larger pipe (m 2)
v : flow velocity in the smaller pipe (m / s)
Energy Loss due to the valve (outlet valve)
where:
f7 : Due to the valve contraction
: for the Gates Valve f7 = 0.15
F. Foundation of Powerhouse
Powerhouse can be classified into „the above ground type‟, the semi-
underground type‟ and „the under ground type‟. Most of small-scale hydropower
plants are of „the above ground type‟ The dimensions for the floor of powerhouse
as well as the layout of main and auxiliary equipment should be determined by
taking into account convenience during operation, maintenance and installation
work, and the floor area should be effectively utilized.
Various types of foundation for powerhouse can be considered depending on the
type of turbine. However the types of foundation for powerhouse can be classified
into „for Impulse turbine‟ (such as Pelton turbine, Turgo turbine and Crossflow
turbine) and „for Reaction turbine‟ (Francis turbine, Propeller turbine).
a. Foundation for Impulse Turbine
In case of impulse turbine, the water which passed by the runner is directly
discharged into air at tailrace. The water surface under the turbine will be
turbulent. Therefore the clearance between the slab of powerhouse and water
surface at the afterbay should be kept at least 30-50cm. The water depth (hc)
at the afterbay can be calculated by following equation.

55
where:
hc: water depth at afterbay (m)
Qd: design discharge (m3
/s)
b : width of tailrace channel (m)
The water level at the afterbay should be higher than estimated flood water
level. Then in case of impulse turbine, the head between the center of turbine
and water level at the outlet became head-loss.
b. Foundation for Reaction Turbine
The water is discharged into the afterbay through the turbine. In case of
reaction turbine, the head between center of turbine and water-level can be
use for power generation. Then it is possible that turbine is installed under
flood water level on condition to furnish the following equipment.
1) Tailrace Gate
2) Pump at powerhouse

56
HYDROLOGY ANALYSIS
1. Introduction
Hydrology analysis was performed, mainly in order to obtain dependable flow which
would be used as design flow rate for micro hydro power plan. The other purpose
was to obtain design flood which would be used as data for designing of weir in the
intake of conveyance channel. To do this analysis, many data are required; they are
precipitation data, climatology data, AWLR or river flow rate data, land use data and
so on. Minimum availability of those data was 10 years therefore an adequate results
can be obtained. The objectives of this analysis are:
a. To drawFlowDurationCurve(FDC)in the river in the study areas
b. To obtain design flood for the return period of 2, 5, 10, 25, 50 and 100 year
return period.
c. To verify the FDC with field measurement to ensure the accuracy of the
analysis.
Technical data of catchment area and main river length for Bayan 1MHP is as
follows:
Table 17. Catchment area of Bayan 1
Location Main River
Catchment area
(km2
)
Main River Length
(km)
Teres Genit (Bayan 1) Muntur 3.18 7.14
In this report, steps of hydrology analysis will be explained. The steps consist of:
a. Data collection, including selection of hydrologic stations which are representative
to the study area;
b. Data consistency test for selected stations;
c. Selection of precipitation distribution type
d. Calculation of design precipitation.

57
Figure 22. Location of study areas, inzet: Lombok Island
Figure 23. Hydrologic stations available in Lombok Island
Segara
Anak
N
Teres Genit (Bayan 1)
Segara
Anak
Teres Genit
(Bayan 1)

58
2. Hydrologic Data Collection
There are many hydrologic station available in Lombok. From those stations, it will be
selected the stations which are representative to the study area. The method chosen
in this selection was polygon Thiessen. From this method, Santong Station was the
only station that is representative to the study area (Figure 2).
Data availability in Santong Station is relatively long, 35 years starting from 1980 to
2014, however in 1980, data available only starting from September, therefore it was
excluded.Data from 1981 to 2013 is daily basis data, meanwhile in 2014, data is
available in hourly basis data. The yearly basis data of Santong Station is shown in
Fig. 3, meanwhile the monthly basis data is shown in Table 2.
Figure 24.Yearly precipitation data in Santong Station
3. Data Consistency Test
This test aims to check whether the data is consistent or not.The method selected
was Rescaled Adjusted Partial Sums (RAPS).If it is proven that some data are not
consistent, then the data must be excluded.
The method of RAPS is briefly explained below. The test was done by using its own
data. Data is sort consecutively, the cumulative deviation from the average value is
than divided by the root-square of cumulative square average deviation. For more
detail explanation, equations of RAPS are shown below (Sri Harto, 1983):
S 00
S Y Yk i
i 1
k
where k = 1,2,3,...,n

59
Table 18. Monthly basis datain Santong Station
No Year
Monthly precipitation (mm)
Total
(mm)
Jan Feb Mar Apr Mei Jun Jul Aug. Sep Oct. Nov Des
1 1980 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.5 67.6 46.5 339.3 454.9
2 1981 797.7 223.0 325.8 164.1 208.5 95.0 307.2 55.4 32.7 147.0 306.6 237.5 2900.5
3 1982 289.7 261.4 156.9 124.9 36.5 2.4 1.2 24.2 0.0 0.0 20.5 404.5 1322.2
4 1983 8.1 449.5 498.7 212.3 178.7 30.6 7.7 0.0 10.1 166.8 370.6 263.8 2196.9
5 1984 542.8 557.6 298.0 221.6 108.3 60.4 6.2 0.0 69.5 32.1 183.8 229.7 2310.0
6 1985 164.6 472.8 273.8 112.2 56.0 8.2 93.0 34.0 2.7 42.5 176.1 113.4 1549.3
7 1986 728.9 367.6 317.0 225.8 53.3 160.0 57.9 0.0 32.7 124.0 171.2 161.9 2400.3
8 1987 771.4 190.1 355.0 89.1 86.5 52.0 2.3 2.0 1.2 0.0 33.0 45.5 1628.1
9 1988 282.3 286.7 662.1 136.9 34.0 0.0 0.0 4.9 8.4 104.6 283.8 247.7 2051.4
10 1989 0.0 0.0 0.0 331.6 232.5 38.9 72.0 13.6 0.4 39.4 61.7 549.9 1340.0
11 1990 795.2 245.3 766.6 221.1 147.7 1.2 7.9 9.6 14.0 120.7 43.7 343.6 2716.6
12 1991 484.7 883.0 133.2 163.2 8.3 0.6 48.6 0.0 1.8 30.9 173.0 196.7 2124.0
13 1992 541.9 787.1 443.2 175.3 83.2 7.7 9.4 2.0 28.1 93.1 57.0 165.1 2393.1
14 1993 171.7 67.7 212.1 215.0 104.6 139.8 19.4 1.0 21.1 46.4 145.2 114.5 1258.5
15 1994 243.7 319.5 666.3 136.3 21.6 1.7 0.3 0.0 0.0 18.0 50.9 344.4 1802.7
16 1995 337.1 181.5 235.9 227.9 71.5 73.2 9.2 0.9 1.6 58.1 219.9 264.5 1681.3
17 1996 187.6 407.8 238.5 105.6 48.9 40.0 12.6 13.8 9.8 91.6 140.1 5.5 1301.8
18 1997 35.0 372.7 16.8 162.6 26.2 9.2 3.0 2.3 137.4 292.2 1057.4
19 1998 302.8 177.1 140.0 25.8 28.6 30.9 123.3 4.7 59.3 123.8 51.1 150.5 1217.9
20 1999 518.1 693.1 319.0 137.8 60.4 45.3 28.2 2.1 192.3 162.9 128.6 2287.8
21 2000 128.7 252.9 315.6 104.9 140.4 41.6 44.0 10.8 68.7 216.4 76.6 0.0 1400.6
22 2001 159.9 91.4 96.3 218.4 60.1 242.8 7.1 22.5 77.8 117.0 78.8 1172.1
23 2002 339.9 152.0 129.6 152.2 6.0 8.5 0.6 3.4 11.7 215.3 388.0 1407.2
24 2003 277.4 528.6 350.4 90.2 102.3 35.8 11.1 21.9 19.6 330.0 290.1 2057.4
25 2004 96.2 515.1 360.4 81.9 111.3 1.0 2.8 2.6 288.6 285.0 1744.9
26 2005 152.5 459.8 487.3 244.7 73.8 4.9 35.7 95.0 49.4 76.3 440.1 2119.5
27 2006 359.2 695.0 257.6 308.4 312.5 24.5 27.5 20.2 44.1 105.5 295.7 2450.2
28 2007 73.8 381.9 633.8 269.1 31.7 93.2 4.1 18.2 13.1 23.3 197.0 462.8 2202.0
29 2008 295.0 378.0 433.0 122.0 97.0 13.0 0.0 6.0 34.0 34.0 117.0 159.0 1688.0
30 2009 431.0 386.0 254.0 23.0 0.0 0.0 0.0 0.0 0.0 63.0 107.0 101.0 1365.0
31 2010 556.0 161.3 208.3 116.4 487.9 219.2 80.9 116.4 135.4 0.0 40.5 149.9 2272.2
32 2011 0.0 152.3 127.9 459.1 258.0 0.0 1.9 0.3 7.9 131.3 228.9 304.0 1671.6
33 2012 500.2 449.0 593.1 121.2 109.4 28.7 24.5 0.0 0.0 72.0 225.6 442.8 2566.5
34 2013 399.7 738.6 344.5 344.8 158.0 87.8 164.6 3.9 5.7 66.2 191.1 787.9 3292.8
35 2014 226.2 260.3 233.6 206.9 178.2 24.1 25.3 2.6 0.0 3.7 267.2 240.7 1668.8
Rata-Rata 320.0 358.4 311.0 172.9 108.7 48.7 36.0 13.4 21.4 66.2 154.8 257.8 1859.2
Min. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 20.5 0.0 454.9
Max. 797.7 883.0 766.6 459.1 487.9 242.8 307.2 116.4 135.4 216.4 370.6 787.9 3292.8

60
S
S
Dk
k
y
D
Y Y
ny
2
i
2
i 1
n
The statistical valueof Q and R
Q = max Sk
0 k n
R = maxSk - min Sk
0 k n 0 k n
According to the two statistical values above (Q and R), it can be calculate the value
of Q/ n and R/ n. The results then are compared with values provided by the
method. If the results are smaller, it means that the data is consistent.
Table 19.Maximum value of Q/n0.5
and R/n0.5
n Q/n0.5
R/n0.5
90% 95% 99% 90% 95% 99%
10 1.05 1.14 1.29 1.21 1.28 1.38
20 1.10 1.22 1.42 1.34 1.43 1.60
30 1.12 1.24 1.48 1.40 1.50 1.70
40 1.13 1.26 1.50 1.42 1.53 1.74
50 1.14 1.27 1.52 1.44 1.55 1.78
100 1.17 1.29 1.55 1.50 1.62 1.85
Source: Sri Harto, 18; 1983

61
Table 20. Consistency test for Santong precipitation data
No. Year
Precipitation
(mm)
SK* DY
2
SK** I SK** I
1 1981 2900.50 999.96 29409.20 1.85 1.85
2 1982 1322.20 421.61 9837.68 0.78 0.78
3 1983 2196.90 717.97 2583.15 1.33 1.33
4 1984 2310.00 1127.43 4931.02 2.08 2.08
5 1985 1549.30 776.18 3628.59 1.43 1.43
6 1986 2400.30 1275.94 7345.78 2.36 2.36
7 1987 1628.06 1003.46 2183.74 1.85 1.85
8 1988 2051.40 1154.31 669.34 2.13 2.13
9 1989 1340.00 593.77 9241.44 1.10 1.10
10 1990 2716.60 1409.82 19586.71 2.60 2.60
11 1991 2124.00 1633.28 1468.61 3.02 3.02
12 1992 2393.10 2125.84 7135.64 3.93 3.93
13 1993 1258.50 1483.79 12124.11 2.74 2.74
14 1994 1802.70 1385.95 281.57 2.56 2.56
15 1995 1681.30 1166.71 1413.76 2.16 2.16
16 1996 1301.80 567.96 10543.94 1.05 1.05
17 1997 1057.40 -275.18 20908.56 -0.51 0.51
18 1998 1217.90 -957.82 13705.95 -1.77 1.77
19 1999 2287.80 -570.57 4410.81 -1.05 1.05
20 2000 1400.60 -1070.51 7351.28 -1.98 1.98
21 2001 1172.10 -1798.95 15606.76 -3.32 3.32
22 2002 1407.20 -2292.30 7158.47 -4.24 4.24
23 2003 2057.40 -2135.44 723.65 -3.95 3.95
24 2004 1744.90 -2291.08 712.50 -4.23 4.23
25 2005 2119.50 -2072.13 1410.06 -3.83 3.83
26 2006 2450.20 -1522.47 8885.95 -2.81 2.81
27 2007 2201.96 -1221.06 2672.11 -2.26 2.26
28 2008 1688.00 -1433.60 1328.67 -2.65 2.65
29 2009 1365.00 -1969.14 8435.50 -3.64 3.64
30 2010 2272.20 -1597.49 4062.60 -2.95 2.95
31 2011 1671.60 -1826.43 1541.62 -3.37 3.37
32 2012 2566.46 -1160.51 13042.49 -2.14 2.14
33 2013 3292.80 231.74 57011.12 0.43 0.43
34 2014 1668.80 0.00 1579.56 0.00 0.00
Total Precipitation (mm) 64,618.48
Average precipitation (mm) 1,900.54
Total DY² 292,931.95
Square of DY² 541.23
Catchment area (km²) 37.73

62
From the analysis, it was obtained that Q and R were4.24 and 8.16, respectively.
With the number of data is 34, it was obtained that value of Q/n0,5
andR/n0,5
was 0.73
and 1.40, respectively. According to Table 3, those two values are smaller than the
maximum value permitted, therefore it can be concluded that precipitation data in
Santong Station starting from 1981 to 2014 is consistent.
4. Maximum Daily Precipitation
For flood analysis, data used is the maximum daily precipitation. In this study areas,
there is only one station representative to the areas. in this case, in order to get
uniform precipitation, that is precipitation that occurred in all area of catchment
uniformly, the precipitation recorded in the station must be corrected with area
reduction factor (ARF) to catch the variability of precipitation intensity in the whole
catchment area. This factor considers on the area of the catchment, and is shown in
Table 5. After considering ARF, the daily maximum precipitation is shown in Table 6.
Table 21. Factor reductionARF
Area, km2
Reduction factor, ARF
1 - 10 0.990
10 - 30 0.970
30 - 3000 0.958
5. Design Precipitation
There are many statistical distribution available, however in the precipitation analysis
there are four distributions are commonly used, they are:
a. Normal distribution,
b. Log Normal distribution,
c. Log Pearson Type III distribution,
d. Gumbel distribution.
In order to decide which distribution is the most suitable for the data, there are some
parameters that can be used.

63
Table 22. The daily maximum precipitation after corrected by ARF
No. Year Date/Month
Max.
Precipitation
(mm)
Max. Precipitation
after ARF (mm)
1 1980 27-Dec 85.50 81.92
2 1981 17-Jan 226.50 217.00
3 1982 9-Jan 189.30 181.36
4 1983 28-Dec 87.00 83.35
5 1984 1-Feb 124.80 119.57
6 1985 3-Mar 113.00 108.26
7 1986 15-Jan 114.00 109.22
8 1987 25-Jan 135.80 130.11
9 1988 24-Mar 220.00 210.78
10 1989 9-Dec 83.50 80.00
11 1990 2-Mar 182.20 174.56
12 1991 11-Feb 98.10 93.99
13 1992 28-Feb 183.00 175.33
14 1993 19-Jun 67.00 64.19
15 1994 14-Dec 98.90 94.75
16 1995 21-Dec 122.20 117.08
17 1996 8-Feb 120.00 114.97
18 1997 15-Feb 140.00 134.13
19 1998 20-Jan 107.00 102.51
20 1999 11-Jan 74.50 71.38
21 2000 1-Mar 152.80 146.39
22 2001 14-Nov 80.50 77.12
23 2002 25-Jan 157.10 150.51
24 2003 7-Dec 227.90 218.35
25 2004 3-Feb 182.70 175.04
26 2005 4-Mar 145.40 139.30
27 2006 25-Feb 115.10 110.27
28 2007 23-Dec 199.00 190.66
29 2008 30-Jan 89.00 85.27
30 2009 13-Jan 58.50 56.05
31 2010 7-Jan 116.20 111.33
32 2011 23-Dec 120.50 115.45
33 2012 4-Feb 89.40 85.65
34 2013 20-Feb 197.00 188.74
35 2014 13-Mar 110.00 105.39

64
Average precipitation )X( , that can be calculated as :
n
Xi
X
n
i 1
__
where:
X : average precipitation (mm),
Xi : precipitation data (mm),
n : number of data.
Deviation standard (S), that can be calculated as:
1
1
2
n
XX
S
n
i
i
Variance coefficient (Cv), that can be calculated as:
X
S
Cv
Skewness coefficient (Cs), that can be calculated as:
3
1
3__
21 Snn
XXin
Cs
n
i
Kurtosis coefficient (Ck), that can be calculated as:
4
1
4__
2
321 Snnn
XXin
Ck
n
i
Table 23.Value of parameters on selection of the most suitable distribution
No Distribution Value
1
2
3
4
Normal
Log Normal
Gumbel
Log Pearson Type III
Cs 0,Ck 3
Cs 3Cv
Cs 1.4,Ck 5.4
None of above
Source : Sri Harto, 1993

65
Table 24. Parameters calculationon selection of the most suitable distribution
No
Max daily
Prec. (mm) Probability (Xi - X ) ( Xi - X )2
( Xi - X )3
( Xi - X )4
1 56.04 2.78 -70.23 4932.58 -346426.87 24330372.94
2 64.19 5.56 -62.09 3855.09 -239359.85 14861697.37
3 71.37 8.33 -54.90 3014.49 -165508.47 9087134.84
4 77.12 11.11 -49.16 2416.35 -118778.78 5838730.91
5 79.99 13.89 -46.28 2142.06 -99139.37 4588403.00
6 81.91 16.67 -44.37 1968.37 -87329.52 3874491.82
7 83.35 19.44 -42.93 1842.93 -79115.74 3396387.18
8 85.26 22.22 -41.01 1682.09 -68988.34 2829442.79
9 85.65 25.00 -40.63 1650.81 -67072.61 2725170.27
10 93.98 27.78 -32.30 1043.00 -33684.34 1087854.13
11 94.75 30.56 -31.53 994.09 -31342.72 988209.38
12 102.51 33.33 -23.77 564.98 -13429.25 319204.58
13 105.38 36.11 -20.90 436.62 -9123.23 190633.18
14 108.25 38.89 -18.02 324.77 -5852.78 105474.91
15 109.21 41.67 -17.06 291.16 -4968.13 84772.90
16 110.27 44.44 -16.01 256.31 -4103.34 65692.58
17 111.32 47.22 -14.96 223.67 -3345.22 50030.24
18 114.96 50.00 -11.32 128.04 -1448.78 16393.50
19 115.44 52.78 -10.84 117.43 -1272.47 13788.97
20 117.07 55.56 -9.21 84.78 -780.66 7188.09
21 119.56 58.33 -6.72 45.12 -303.05 2035.58
22 130.10 61.11 3.82 14.60 55.79 213.17
23 134.12 63.89 7.84 61.54 482.75 3786.99
24 139.29 66.67 13.02 169.46 2206.06 28718.20
25 146.38 69.44 20.11 404.29 8129.15 163453.25
26 150.50 72.22 24.23 586.92 14219.01 344476.20
27 174.55 75.00 48.27 2330.21 112484.50 5429879.85
28 175.03 77.78 48.75 2376.68 115866.34 5648629.29
29 175.31 80.56 49.04 2404.79 117927.63 5783011.74
30 181.35 83.33 55.07 3033.15 167047.92 9200005.84
31 188.73 86.11 62.45 3900.08 243562.78 15210654.15
32 190.64 88.89 64.37 4143.07 266675.27 17164994.36
33 210.76 91.67 84.48 7137.66 603022.41 50946137.84
34 216.99 94.44 90.71 8228.60 746430.23 67709918.93
35 218.33 97.22 92.05 8473.73 780030.77 71804057.00
Total 4419.64 0.00 71279.51 1796767.08 323901045.98
Average (mm) 126.275

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