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19-091

THE PROJECT FOR

ASSESSING AND INTEGRATING CLIMATE CHANGE IMPACTS INTO THE WATER RESOURCES MANAGEMENT PLANS

FOR BRANTAS AND MUSI RIVER BASINS

(Water Resources Management Plan)

Composition of Final Report Volume I EXECUTIVE SUMMARY Volume II MAIN REPORT Part 1 General

Part 2 Study for Brantas River Basin

Part 3 Study for Musi River Basin

Part 4 Capacity Strengthening

Part 5 Conclusions and Recommendations Volume III SUPPORTING REPORT & HANDBOOK (1/2) Supporting Report A : HYDROLOGY AND HYDRAULICS

(Brantas River Basin)

Supporting Report B : HYDROLOGY AND HYDRAULICS (Musi River Basin)

Supporting Report C : HYDROGEOLOGY AND GROUND WATER MANAGEMENT

Supporting Report D : SPATIAL PLAN AND LAND USE

Supporting Report E : AGRICULTURE AND IRRIGATION

Supporting Report F : WATER SUPPLY AND SEWERAGE Volume III SUPPORTING REPORT & HANDBOOK (2/2) Supporting Report G : RIVER FACILITIES MANAGEMENT

Supporting Report H : SABO MANAGEMENT

Supporting Report I : WET LAND MANAGEMENT AND WATERSHED CONSERVATION

Supporting Report J : ENVIRONMENTAL AND SOCIAL CONSIDERATIONS

Supporting Report K : IMPLEMENTATION PLAN AND COST ESTIMATE

Supporting Report L : ECONOMIC ANALYSIS AND PROJECT EVALUATION

REPORT ON COMPONENT 1（ANNEX）

HANDBOOK Volume IV DATA BOOK/CD

Brantas River Basin

Cost Estimate: August 2017 Price

Exchange Rate: USD 1.0 = IDR 13,341.82 = JPY 109.84

Musi River Basin

Cost Estimate: March 2019 Price

Exchange Rate: USD 1.0 = IDR 14,230.00 = JPY 111.10

i

Abbreviations and Glossaries

Indonesia English

AMDAL Analisis Mengenai Dampak Lingkungan Environmental Impact Assessment

APBN Anggaran Pendapatan dan Belanja Negara National Budget

BAKOSURTANAL

Badan Koordinasi Survei dan Pemetaan Nasional

National Coordination Agency for Surveys and Mapping

BAPPEDA Badan Perencanaan Pembangunan Daerah Regional Planning Agency

BAU Business As Usual

BBWS Balai Besar Wilayah Sungai Large River Basin Organization

BCM - Business Continuity Management

BCP - Business Continuity Plan

BCR - Benefit Cost Ratio

BIG Badan Informasi Geospasial Geospatial Information Agency

BKSDA Balai Konservasi Sumber Daya Air Water Resources Conservation Center

BLHD Badan Linkungan Hidup Daerah Regional Living Environment Agency

BMKG Bandan Metorologi, Klimatologi, dan Geofisika

Meteorological, Climatological, and Geophysical Agency

BNPB Badan Nasional Penanggulangan Bencana National Disaster Management Agency

BOD Bio-chemical Oxygen Demand

BPBD Badan Penanggulangan Bencana Daerah Regional Agency for Disaster Management

BPDASHL Balai Pengelolaan Daerah Aliran Sungai dan Hutan Lindung

Brantas-Sampean Watershed and Protected Forest Management Organization

BPPW Balai Prasarana Permukiman Wilayah Regional Settlement Infrastructure Agency

BPS Badan Pusat Stasistik Central Bureau of Statistics

BRG Badan Restorasi Gambut Peatland Restoration Agency

COD - Chemical Oxygen Demand

DANIDA - Ministry of Foreign Affairs of Denmark

D/D - Detailed Design

DEM Digital Elevation Model

DGWR Direktorate Jenderal Sumber Daya Air Directorate General of Water Resources

DISHUT Dinas Kehutanan Department of Forestry

DGWR Direktorat Jenderal Sumber Daya Air Directorate General of Water Resources

DLH Dinas Lingkungan Hidup Department of Environmental

DNPI Dewan Nasional Perubahan Iklim National Council on Climate Change

DO - Dissolved Oxygen

DRR - Disaster Risk Reduction

DPRKPCK Dinas Perumahan Rakyat, Kawasan Permukiman dan Cipta Karya

Department of Public Housing, Settlement and Cipta Karya

EC - Electric Conductivity

EIA Analisis Mengenai Dampak Lingkungan Environmental Impact Assessment

EIRR Economic Internal Rate of Return

ESDM Kementerian Energi dan Sumber Daya Mineral

Ministry of Energy and Mineral Resources

EWS Sistem Peringatan Eini Early Warning System

ii

Indonesia English

F/S - Feasibility Study

FFWS Sistem Peramalan dan Peringatan Banjir Flood Forecasting and Warning System

FPL - Flood Protection Level

FSL Full Supply Level

FY - Fiscal Year

GCM Global Climate Model

GDP - Gross Domestic Product

GOI - Government of Indonesia

GOJ - Government of Japan

GRDP Gross Regional Domestic Product

GSM - Global System for Mobile communications

HDSS - Hydrometeorological Decision Support System

HydroSHEDS - Hydrological data and maps based on SHuttle Elevation Derivatives at multiple Scales

IEE - Initial Environmental Evaluation

IMS Izin Mendinikan Bangnan Building construction permit

iRIC - International River Interface Cooperative

IWRM Pengelolaan Sumber Daya Air Terpadu Integrated Water Resources management

JATIM Jawa Timur East Java

JBIC - Japan Bank for International Cooperation

JICA - Japan International Cooperation Agency

KLHK Kementerian Lingkungan Hidup dan Kehutanan

Ministry of Environment and Forestry

KP Kriteria Perencanaan Design Criteria for Irrigation Networks

KPH Kesatuan Pemangkuan Hutan Forest management unit

KPHP Kesatuan Pengelolaan Hutan Produksi Production Forest Management Unit

LARAP - Land Acquisition and Resettlement Action Plan

LIBOR - London Interbank Offered Rate

LWL - Low Water Level

MSBL Musi-Sugihan-Banyuasin-Lemaure Musi-Sugihan-Banyuasin-Lemau

MDG’s - Millenium Development Goal

MH Musim Hujan Rainy season

MLIT - Ministry of Land, Infrastructure and Transportation and Tourism

MK Musim Kemarau Dry season

MOL Minimum Operation Level

M/P - Master Plan

MPL - Micro Pulse Lidar

MPWH Pekerjaan Umum dan Perumahan Rakyat Public Works and Public Housing

MPWPH Kementerian Pekerjaan Umum dan Perumahan Rakyat

Ministry of Public Works and Housing

iii

Indonesia English

MSA - Multiple Scenario Approach

NGO - Non-Governmental organization

NPV - Net Present Value

NRW - Non-Revenue Water

O&M - Operation & Maintenance

ODA - Official Development Assistance

OKI Ogan Komering Ilir -

OKU Ogan Komering Ulu -

P2AT Proyek Pengembangan Air Tanah Groundwater Development Project

PCO - Point of Cost Optimum

PDAM Perusahaan Daerah Air Minum Indonesian Regional Water Utility Company

PJT-I Perum Jasa Tirta I Jasa Tirta I Public Corporation

PKL - Develop Local Activity Centers

PKN - National Activity Center

PKW - Regional Activity Center

PLN Perusahaan Listrik Negara State Electric Company

POLA Rencana Strategis Manajemen Sumber Daya Air

Water Resources Management Strategic Plan

PP Peraturan Pemerintah Government regulation

PR4 - Progress Report-4

PSDA Pengelolaan Samer Daya Air Water Resources Management

RAD-GRK - Regional Action Plan on Greenhouse Gas

RENCANA Rencana Penerapan Manajemen Sumber Daya Air

Water Resources Management Implementation Plan

RO - Reverse Osmosis

RPJM Rencana Pembangunan Jangka Menegah Mid-term Development Plan

RPJMD Rencana Pembangunan Jangka Menegah Daerah

Medium Term Development Plan of Region

RPJP Rencana Pembangunan Jangka Panjang Long-term Development Plan

RTH Ruang Terbuka Hijau Green open space

RTRW Rencana Tata Ruang Wilayah Spatial Plan

RUPTL Rencana Usaha Penyediaan Tenaga Listrik Electricity Supply Business Plan

RWL - Reservoir Water Level

SEA - Strategic Environmental Assessment

SHM - Stakeholder Meetings

SHVP Surabaya Haven Vaste Peil Surabaya Harbor Flood Level

SID - Study Investigation Design

SNI Standar National Indonesia Indonesian National Standard

SPPL - -

SRI - System Rice Intensification

SSBSAP - South Sumatra Biodiversity Strategy and Action Plan

iv

Indonesia English

TKPSDA Tim Koordinasi Pengelolaan Sumber Daya Air

Water Resources Management Coordination Team

TOT - Training of Trainers

TPA - Development of regional Ultimate Waste Management System

TRGD Tim Restorasi Gambut Daerah Peat Restoration Team

UNISDR - United Nations International Strategy for Disaster Reduction

UPL-UKL Upaya Pemantauan Lingkungan Hidup dan Upaya Pengelolaan Lingkungan Hidup

Environmental Management and Monitoring Plan

USLE - Universal Soil Loss Equation

VAT Value Added Tax

WEB-DHM - Water Energy Budget-based Distributed Hydrological Model

WREFR & CIP - Water Resources Existing Facilities Rehabilitation & Capacity Improvement Project

WUA - Water Users Association

Supporting Report A

HYDROLOGY AND HYDRAULICS (Brantas River Basin)

A-i

The Republic of Indonesia

THE PROJECT

FOR

ASSESSING AND INTEGRATING CLIMATE CHANGE IMPACTS INTO

THE WATER RESOURCES MANAGEMENT PLANS FOR

BRANTAS AND MUSI RIVER BASINS

(WATER RESOURCES MANAGEMENT PLAN)

FINAL REPORT

Supporting Report A : HYDROLOGY AND HYDRAULICS (Brantas River Basin)

Table of Contents

Page

PART 1 GENERAL

CHAPTER A1 GENERAL ................................................................................................. A1-1

A1.1 General ............................................................................................................ A1-1

A1.2 Purpose of the Water Balance Analysis .......................................................... A1-1

A1.3 Study Flow of the Water Balance Analysis ................................................... A1-1

A1.4 Study Scenarios ............................................................................................... A1-2

CHAPTER A2 BUILDING WATER BALANCE MODEL ............................................ A2-1

A2.1 Natural Flow of the Brantas River Basin ........................................................ A2-1

A2.2 Structures in the Brantas River Basin .............................................................. A2-7

A2.3 Water Demand ................................................................................................. A2-7

A2.3.1 Municipal and Industrial Water Demand ............................................ A2-7

A2.3.2 Irrigation Water Demand .................................................................... A2-7

A2.3.3 Hydropower Demand .......................................................................... A2-7

A2.3.4 Priority of Water Demand ................................................................... A2-8

A2.4 Environmental Flow Requirement .................................................................. A2-8

A2.5 Hydraulics of Connecting Tunnel between Sutami and Lahor Reservoir ....... A2-9

A2.6 Other Assumptions of Water Balance Analysis ............................................ A2-11

A2.7 Network Flow Diagram ................................................................................. A2-11

A2.8 Water Balance Calculation Model ................................................................. A2-14

CHAPTER A3 CALIBRATION OF MODEL .................................................................. A3-1

A3.1 Calibration of Time Lag .................................................................................. A3-1

A3.2 Calibration with Actual Record ....................................................................... A3-2

A-ii

CHAPTER A4 RESULT OF WATER BALANCE SIMULATION ................................ A4-1

A4.1 Demand and Supply Balance ........................................................................... A4-1

A4.1.1 Scenario 1............................................................................................ A4-1

A4.1.2 Scenario 2............................................................................................ A4-2

A4.1.3 Scenario 3............................................................................................ A4-3

A4.1.4 Scenario 4............................................................................................ A4-4

A4.1.5 Scenario 5............................................................................................ A4-5

A4.1.6 Scenario 6............................................................................................ A4-6

A4.1.7 Scenario 7............................................................................................ A4-7

A4.1.8 Scenario 8............................................................................................ A4-8

A4.2 Hydropower Generation .................................................................................. A4-9

A4.2.1 Scenario 1............................................................................................ A4-9

A4.2.2 Scenario 2.......................................................................................... A4-10

A4.2.3 Scenario 3.......................................................................................... A4-11

A4.2.4 Scenario 4.......................................................................................... A4-12

A4.2.5 Scenario 5.......................................................................................... A4-13

A4.2.6 Scenario 6.......................................................................................... A4-14

A4.2.7 Scenario 7.......................................................................................... A4-15

A4.2.8 Scenario 8.......................................................................................... A4-16

A4.3 Reservoir Volume .......................................................................................... A4-17

A4.3.1 Scenario 1.......................................................................................... A4-17

A4.3.2 Scenario 2.......................................................................................... A4-21

A4.3.3 Scenario 3.......................................................................................... A4-25

A4.3.4 Scenario 4.......................................................................................... A4-29

A4.3.5 Scenario 5.......................................................................................... A4-33

A4.3.6 Scenario 6.......................................................................................... A4-37

A4.3.7 Scenario 7.......................................................................................... A4-41

A4.3.8 Scenario 8.......................................................................................... A4-42

PART 2 HYDRAULICS

CHAPTER A5 GENERAL ................................................................................................. A5-1

A5.1 Natural Condition in Brantas River Basin ....................................................... A5-1

A5.1.1 Topographic Data................................................................................ A5-1

A5.1.2 Land Use ............................................................................................. A5-1

A5.2 Present Inundation Area .................................................................................. A5-1

CHAPTER A6 TARGET AREA OF FLOOD INUNDATION SIMULATION ............. A6-1

CHAPTER A7 METHODOLOGY OF LOOD INUNDATION SIMUALTION ........... A7-1

A7.1 Relationship between Inundation Pattern and Analysis Model ....................... A7-1

A7.2 Hydraulic Analysis Model ............................................................................... A7-1

A7.2.1 1-D Non-uniform Flow Analysis ........................................................ A7-1

A-iii

A7.2.2 2-D Unsteady Flow Analysis .............................................................. A7-3

A7.2.3 1-D and 2-D Unsteady Flow Analysis ................................................ A7-4

CHAPTER A8 FLOOD INUNDATION ANALYSIS FOR BRANTAS MAINSTREAM AND PORONG RIVER ................................................................................ A8-1

A8.1 Estimation for Flow Capacity for Brantas Mainstream ................................... A8-1

A8.1.1 Setting for Calculation ........................................................................ A8-1

A8.1.2 Assessment of Effects of Existing River Facilities in Brantas Mainstream ......................................................................................... A8-2

A8.2 Flood Inundation Analysis .............................................................................. A8-4

A8.2.1 Simulation Model................................................................................ A8-4

A8.2.2 Conditions of Analysis ........................................................................ A8-4

A8.2.3 Model Calibration ............................................................................... A8-6

A8.2.4 Result of Calculation........................................................................... A8-7

CHAPTER A9 FLOOD INUNDATION AT PRESENT AND FUTURE CLIMATE CHANGE CONDITION IN TRIBUTRIES ............................................................................. A9-1

A9.1 Widas River Basin ........................................................................................... A9-1

A9.1.1 Present Condition of Widas River Basin ............................................ A9-1

A9.1.2 Simulation Model................................................................................ A9-1

A9.1.3 Conditions of Analysis ........................................................................ A9-1

A9.1.4 Model Calibration ............................................................................... A9-3

A9.1.5 Result of Flood Inundation Analysis .................................................. A9-5

A9.2 Sadar River Basin .......................................................................................... A9-10

A9.2.1 Present Condition of Sadar River Basin ........................................... A9-10

A9.2.2 Simulation Model.............................................................................. A9-11

A9.2.3 Conditions of Analysis ...................................................................... A9-11

A9.2.4 Model Calibration ............................................................................. A9-14

A9.2.5 Result of Flood Inundation Analysis ................................................ A9-15

A9.3 Brangkal River Basin .................................................................................... A9-21

A9.3.1 Present Condition of Brangkal River Basin ...................................... A9-21





A9.4 Tulungagung Area ......................................................................................... A9-30

A9.4.1 Present Condition of Tulungagung Area .......................................... A9-30





A-iv

List of Tables

Page

Table A1.4.1 Scenarios Adopted for Water Balance Analysis for the Brantas River Basin ...... A1-2

Table A2.2.1 For the network model, following structures are considered in the model .......... A2-7

Table A2.3.1 Hydropower Operation Hours and Discharge ..................................................... A2-8

Table A2.4.1 Flow Duration of the Stream Flow at Sutami, Mrican and New Lengkong from 2003 to 2012 ........................................................................................................ A2-9

Table A2.4.2 Assigned Environmental Flow at Sutami, Mrican and New Lengkong .............. A2-9

Table A3.1.1 Calculation of Time Lag of Flow ........................................................................ A3-1

Table A7.1.1 Relationship between Inundation Pattern and Analysis Model ........................... A7-1

Table A8.1.1 Probable Peak Discharge under Future Conditions ............................................. A8-1

Table A8.1.2 Freeboard Comparison with Present Condition and Future Condition ................ A8-3

Table A8.2.1 Calculation Condition for Flood Inundation Analysis on Porong River ............. A8-4

Table A8.2.2 Summary of Inundation Depth and Inundated Area ............................................ A8-7

Table A9.1.1 Boundary Condition of Downstream End (Water Level) .................................... A9-2

Table A9.1.2 Peak Discharge of Upper End Boundary ............................................................. A9-3

Table A9.1.3 Result of Calibration in Widas River Basin ......................................................... A9-4

Table A9.1.4 Results of Flood Inundation Analysis (Widas River Basin) ................................ A9-5

Table A9.2.1 Boundary Condition of Downstream End (Water Level: EL.m) ....................... A9-11

Table A9.2.2 Peak Discharge of Upper End Boundary ........................................................... A9-13

Table A9.2.3 Results of Flood Inundation Analysis (Sadar River Basin) ............................... A9-16

Table A9.3.1 Boundary Condition of Downstream End (Water Level: EL.m) ....................... A9-22

Table A9.3.2 Peak Discharge of Upper End Boundary (Ngotok Ring River) ......................... A9-23

Table A9.3.3 Results of Flood Inundation Analysis (Ngotok Ring River Basin) ................... A9-25

Table A9.4.1 Modified Peak Discharge under Present Condition ........................................... A9-31

Table A9.4.2 Flood Volume and Coefficient Number for Hydrograph of Each Return Period under Three Future Condition ........................................................................... A9-32

Table A9.4.3 Peak Discharge of Upper End Boundary ........................................................... A9-33

Table A9.4.4 Results of Flood Inundation Analysis (Tawing River Basin) ............................ A9-35

A-v

List of Figures

Page

Figure A1.3.1 Analysis Flow of the Water Balance Analysis of the Brantas River Basin .......... A1-1

Figure A2.1.1 Flow Duration Curves at Sutami, Mrican, New Lengkong Dam Sites and Widas River for Three GCMs ......................................................................................... A2-2

Figure A2.1.2 Sequence of Discharge Data at upstream of Sutami Dam under Future Condition ............................................................................................................................. A2-3

Figure A2.1.3 Sequence of Discharge Data at Mrican Barrage under Future Condition ........... A2-4

Figure A2.1.4 Sequence of Discharge Data at New Lengkong Dam under Future Condition ... A2-5

Figure A2.1.5 Sequence of Discharge Data of Widas River at Confluence of Brantas River under Future Condition ........................................................................................ A2-6

Figure A2.5.1 Connecting Tunnel Alignment and Photos in Construction Stage ..................... A2-10

Figure A2.5.2 Discharge Rating Curve for Manning’s Roughness Coefficient of n = 0.013, 0.0145 and 0.016 ............................................................................................... A2-11

Figure A2.7.1 Basin Diagram in the Brantas River Basin for Water Balance (1/2-2/2) ........... A2-12

Figure A2.8.1 Water Balance Simulation Model of the Brantas River Basin ........................... A2-14

Figure A3.2.1 Comparison of the Model Result with Actual Observation Record .................... A3-3

Figure A3.2.2 Comparison of the Model Result with Actual Observation Record .................... A3-3

Figure A5.1.1 Land Use in Brantas River Basin ........................................................................ A5-1

Figure A5.2.1 Inundation area in Brantas River Basin ............................................................... A5-2

Figure A7.2.1 Representation of Terms in the Energy Equation ................................................ A7-2

Figure A7.2.2 Default Conveyance Method in HEC-RAS ......................................................... A7-3

Figure A7.2.3 Concept Image of Inundation Model ................................................................... A7-6

Figure A8.1.1 Relationship between Basin Mean Rainfall and Peak Discharge ........................ A8-1

Figure A8.1.2 River Profile and Water Surface under 50-year Probable Flood ......................... A8-2

Figure A8.1.3 Location of Overtop Sections under 50-year Probable Flood ............................. A8-3

Figure A8.2.1 Model Area of Inundation Analysis in Poring River ........................................... A8-5

Figure A8.2.2 Hydrograph for Porong River in return period 50 year for Each Climate Condition ............................................................................................................. A8-5

Figure A8.2.3 Downstream Condition at Surabaya Sea Level ................................................... A8-6

Figure A8.2.4 Calibration for Porong River ............................................................................... A8-6

Figure A8.2.5 Time Sequence of Inundation Flow in Porong River under Present Condition ... A8-7

Figure A8.2.6 Maximum Inundation Depth and Area in Present Climate .................................. A8-7

Figure A8.2.7 Maximum Inundation Depth and Area in Low Scenario ..................................... A8-8

Figure A8.2.8 Maximum Inundation Depth and Area in Medium Scenario ............................... A8-8

Figure A8.2.9 Maximum Inundation Depth and Area in High Scenario .................................... A9-8

Figure A9.1.1 Target Area of Analysis in Widas River Basin .................................................... A9-1

A-vi

Figure A9.1.2 Hydrograph of Each Upper End Boundary Condition (Present Condition) ........ A9-2

Figure A9.1.3 Design Flood Discharge in Widas River Basin ................................................... A9-4

Figure A9.1.4 Time sequence of Inundation Flow in Widas river .............................................. A9-5

Figure A9.1.5 Maximum Inundation Depth and Area in Widas River Basin under Present Condition ............................................................................................................. A9-7

Figure A9.1.6 Maximum Inundation Depth and Area in Widas River Basin under Medium Scenario ............................................................................................................... A9-8

Figure A9.1.7 Maximum Inundation Depth and Area in Widas River Basin under Low Scenario ............................................................................................................................. A9-9

Figure A9.1.8 Maximum Inundation Depth and Area in Widas River Basin under High Scenario ............................................................................................................. A9-10

Figure A9.2.1 Target Area of Analysis in Sadar River Basin ................................................... A9-11

Figure A9.2.2 Hydrograph of Each Upper End Boundary Condition (Present Condition) ...... A9-12

Figure A9.2.3 Calibration in Sadar River Basin ....................................................................... A9-14

Figure A9.2.4 Time sequence of Inundation Flow in Sadar River ........................................... A9-15

Figure A9.2.5 Maximum Inundation Depth and Area in Sadar River Basin under Present Condition ........................................................................................................... A9-17

Figure A9.2.6 Maximum Inundation Depth and Area in Sadar River Basin under Medium Scenario ............................................................................................................. A9-18

Figure A9.2.7 Maximum Inundation Depth and Area in Sadar River Basin under Low Scenario ........................................................................................................................... A9-19

Figure A9.2.8 Maximum Inundation Depth and Area in Sadar River Basin under High Scenario ........................................................................................................................... A9-20

Figure A9.3.1 Target Area of Analysis in Ngotok Ring River Basin ........................................ A9-21

Figure A9.3.2 Hydrograph of Each Upper End Boundary Condition....................................... A9-22

Figure A9.3.3 Design Flood Discharge in Ngotok Ring River Basin ....................................... A9-24

Figure A9.3.4 Calibration in Ngotok Ring River ..................................................................... A9-24

Figure A9.3.5 Maximum Inundation Depth and Area in Ngotok Ring River Basin under `Present Condition ............................................................................................. A9-26

Figure A9.3.6 Maximum Inundation Depth and Area in Ngotok Ring River Basin under Medium Scenario ............................................................................................... A9-27

Figure A9.3.7 Maximum Inundation Depth and Area in Ngotok Ring River Basin under Low Scenario ............................................................................................................. A9-28

Figure A9.3.8 Maximum Inundation Depth and Area in Ngotok Ring River Basin under High Scenario ............................................................................................................. A9-29

Figure A9.4.1 Target Area of Analysis in Tawing River Basin ................................................. A9-30

Figure A9.4.2 Hydrograph of Each Upper End Boundary Condition....................................... A9-31

Figure A9.4.3 Modified Hydrograph of Each Upper End Boundary Condition ....................... A9-32

Figure A9.4.4 Design Flood Discharge in Tawing River Basin ................................................ A9-33

A-vii

Figure A9.4.5 Calibration Result in Tawing River ................................................................... A9-34

Figure A9.4.6 Maximum Inundation Depth and Area in Tawing River Basin under Present Condition ........................................................................................................... A9-36

Figure A9.4.7 Maximum Inundation Depth and Area in Tawing River Basin under Medium Scenario ............................................................................................................. A9-37

Figure A9.4.8 Maximum Inundation Depth and Area in Tawing River Basin under Low Scenario ............................................................................................................. A9-38

Figure A9.4.9 Maximum Inundation Depth and Area in Tawing River Basin under High Scenario ............................................................................................................. A9-39

The Project for Assessing and Integrating Climate Change Impacts into the Water Resources Management Plans for Brantas and Musi River Basins Final Report (Water Resources Management Plan) Supporting Report A

Nippon Koei Co., Ltd. CTI Engineering International Co., Ltd. The University of Tokyo

PART 1 HYDROLOGY

GENERAL

A1.1 General

This annex describes the procedure of development of the water balance model and the

simulation of the water balance analysis of the Brantas River Basin.

A1.2 Purpose of the Water Balance Analysis

The purpose of the water balance analysis is to confirm the water demand sufficiency of the

basin through the water balance simulation. The simulation is conducted by running the water

balance simulation model which is uniquely developed for the subject basin. The simulation

scenarios are a priori prepared and the sensitivity of the demand sufficiency for the scenarios

are checked through simulation runs. The scenarios include the present and future development

conditions, and climate with or without climate change impact, and the water supply system

with enhanced resilience against climate change and the system with mitigation measures for

climate change impact.

A1.3 Study Flow of the Water Balance Analysis

The network flow model is established based on the water allocation plan of the Brantas River

Basin. Then, the network flow model is calibrated with actual stream flow record, so as that

the model correctly reproduces the flow regime of the Brantas River Basin. After the

calibration of the model, the model data such as planned water demand, natural stream flow

from watersheds are inputted into the model, and those values vary dependent on the assumed

year, development scenarios, and climate conditions. The type of water demands includes

irrigation, domestic supply and hydropower operation. The flow of the water balance analysis

for the Brantas River Basin is shown in Figure A1.3.1.

Source: JICA Project Team 2

Figure A1.3.1 Analysis Flow of the Water Balance Analysis of the Brantas River Basin

Start

Calibration of the model1) Flow lag time2) Comparison of simulated model with acutual stream flow record

Run the models

Data for each scenario‐ Natural stream flow ‐ Irrigation demand‐ Domestic water demand

Determine the analysisscenarios

Preparation of data for water balance analysis

Buildingnetwork flow model

Compiling the result

End

‐ Stream flow record of the Brantas River.‐ Irrigation supply record‐ Domestic water demand

‐ Reservoir operation rule‐ Evaporation‐ Return flow ratio

December 2019 A1-1


Nippon Koei Co., Ltd. December 2019 CTI Engineering International Co., Ltd. The University of Tokyo

A1.4 Study Scenarios

The network flow model is established based on the water allocation plan of the Brantas River

Table A1.4.1 Scenarios Adopted for Water Balance Analysis for the Brantas River Basin

Scenario Assumed

Year Climate

Irrigation Area

Domestic Water

Demand

Reservoir Sedimentation

Scenario 1 2015 Present 2015 Area 2015 2015 Scenario 2 2030 Present 2030 Area 2030 2030 Scenario 3 2050 Present* 2050 Area 2050 2050 Scenario 4 2050 2050 Middle 2050 Area 2050 2050 Scenario 5 2050 2050 Low 2050 Area 2050 2050 Scenario 6 2050 2050 High 2050 Area 2050 2050

*Assuming no climate change is occurred. Source: JICA Project Team 2

In addition to the above scenarios, following scenarios are analyzed for the calculation of the

resilience of the water resources management.

1) Applying Control Water Level (CWL) to Sutami reservoir for FSL 272.5m in rainy season

and FSL274.9 m for dry season. (Scenario 7)

2) Applying Control Water Level (CWL) to Sutami reservoir for FSL 272.5m in rainy season

and FSL274.9 m for dry season, and apply LWL to EL.246.0 m. (Scenario 8)

A1-2



BUILDING WATER BALANCE MODEL

A2.1 Natural Flow of the Brantas River Basin

The river flow without any utilization of water by human activity is called “natural flow.”

Natural flow is the flow of the river naturally the river without storage in dams and

consumption by irrigation and domestic use. The natural flow is estimated through

hydrological model, or actual river flow record with adding recorded water extraction from

the river such as irrigation.

In this project, the natural flow of the Brantas River and tributaries in the Brantas River

Basin is estimated by Team 1. A hydrological model called “WEB-DHM” is used and

precipitation and other climatic parameters are applied into the model. The details of the

stream flow estimation are described in the report of Component-1.

Team 1 estimated the natural flow of the Brantas River and its tributaries based on the

selected three GCMs according the degree of the changes to the present climate. The

selected GCMs are namely low, medium and high scenarios. The flow duration curves

(FDCs) under the present climate and three GCMs are made for the Sutami dam, the Mrican

barrage, the New Lengkong barrage sites and Widas River at confluence point as shown in

Figure A2.1.1. And Figure A2.1.2 shows sequence of discharge at four locations.

The natural flow estimated for the climate scenario of present and future conditions for

high, middle, and low degree of climate change impact.

A2-1



Sutami Mrican

New Lengkong Widas River at Confluence of Brantas River


Figure A2.1.1 Flow Duration Curves at Sutami, Mrican, New Lengkong Dam Sites and Widas

River for Three GCMs

As shown in Figure A2.1.1, all FDCs of future climates are lower than that of present in

the range in the low flow which is below 10% of exceedance probability in percent. As it

is indicated by the name, high scenario is the lowest in the lower flow. The low impact case

positioned in the highest of the three GCMs but it is still lower than present climate.

However, the discharge of low impact case sometimes become lowest value among three

cases during dry season as shown in Figure A2.1.2.

0

50

100

150

200

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Present

Low

Middle

High

Exceedance Probability

Dis

char

ge (m

3/s)

0

100

200

300

400

500

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Present

Low

Middle

High


Dis

char

ge (m

3/s)

0

200

400

600

800

1000

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Present

Low

Middle

High


Dis

char

ge (m

3/s)

0

10

20

30

40

50

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Present

Low

Middle

High


Dis

char

ge (m

3/s)

A2-2




Figure A2.1.2 Sequence of Discharge Data at upstream of Sutami Dam under Future Condition

10

100

1,000

2047 2048 2049 20502046

Dis

char

g (m

3/s)

10

100

1,000

2052 2053 2054 20552051

Dis

char

g (m

3/s)

10

100

1,000

2057 2058 2059 20602056

Dis

char

g (m

3/s)

10

100

1,000

2062 2063 2064 20652061

Dis

char

g (m

3/s)

LegendHigh

MiddleLow

LegendHigh

MiddleLow

LegendHigh

MiddleLow

LegendHigh

MiddleLow

A2-3




Figure A2.1.3 Sequence of Discharge Data at Mrican Barrage under Future Condition

10

100

1,000

2047 2048 2049 20502046

Dis

char

g (m

3/s)

10

100

1,000

2052 2053 2054 20552051

Dis

char

g (m

3/s)

10

100

1,000

2057 2058 2059 20602056

Dis

char

g (m

3/s)

10

100

1,000

2062 2063 2064 20652061

Dis

char

g (m

3/s)

LegendHigh

MiddleLow

LegendHigh

MiddleLow

LegendHigh

Middle

LegendHigh

MiddleLow

A2-4




Figure A2.1.4 Sequence of Discharge Data at New Lengkong Dam under Future Condition

10

100

1,000

2047 2048 2049 20502046

Dis

char

g (m

3/s)

10

100

1,000

2052 2053 2054 20552051

Dis

char

g (m

3/s)

10

100

1,000

2057 2058 2059 20602056

Dis

char

g (m

3/s)

10

100

1,000

2062 2063 2064 20652061

Dis

char

g (m

3/s)

LegendHigh

MiddleLow

LegendHigh

MiddleLow

LegendHigh

MiddleLow

LegendHigh

MiddleLow

A2-5




Figure A2.1.5 Sequence of Discharge Data of Widas River at Confluence of Brantas River under

Future Condition

1

10

100

2047 2048 2049 20502046

Dis

char

g (m

3/s)

1

10

100

2052 2053 2054 20552051

Dis

char

g (m

3/s)

1

10

100

2057 2058 2059 20602056

Dis

char

g (m

3/s)

1

10

100

2062 2063 2064 20652061

Dis

char

g (m

3/s)

LegendHigh

MiddleLow

LegendHigh

MiddleLow

LegendHigh

MiddleLow

LegendHigh

MiddleLow

A2-6



A2.2 Structures in the Brantas River Basin

Table A2.2.1 For the network model, following structures are considered in the model.

No. Present Planned in Review POLA Planned but not included

in Review POLA

1 Sengguruh Tugu Genteng I

2 Sutami-Lahor Lesti III Kampak

3 Wlingi Bagong Babadan

4 Lodoyo Semantok Konto II

5 Wonorejo Beng Kuncir

6 Tiudan Long Storage Porong Kedungwarak

7 Segawe Long Storage Kalimati Ketandan

8 Tulungagung Long Storage Wonokromo

9 Selorejo

10 Mrican

11 Bening

12 Jatimlerek

13 Mentrus

14 New Lengkong Source: JICA Project Team 2

The details of the structures in the Brantas River Basin is described in the main report.

A2.3 Water Demand

A2.3.1 Municipal and Industrial Water Demand

The municipal and industrial water demand is estimated for each scenario. The details of

the estimation of municipal and industrial water demand is described in the main report.

A2.3.2 Irrigation Water Demand

The irrigation water demand is estimated for each scenario. The details of the estimation of

municipal and industrial water demand is described in the main report.

A2.3.3 Hydropower Demand

The hydropower demand is estimated based on the past annual water allocation plan

(RAAT) for the Brantas River Basin1. RAAT is abbreviation of “Rencana Alokasi Air

Tahunan” namely annual water allocation plan. RAAT is formulated by TKPSDA and is

referred as a guideline of reservoir operation, hydropower operation, water allocation to

irrigation, and municipal water demand. The planning period is from December to

November.

According to RAAT, the water allocation is determined based on the assumed climate

condition in the year. The climate condition is determined referring to the long term weather

forecast issued by BMKG.

In the water balance analysis, the hydropower operation is assumed to employ the operation

hours set for normal weather condition in RAAT. The assumed operation hours are set to

the hydropower stations of Senggurh, Sutami, Wlingi, Lodoyo and Selorejo, and the

assumed operation hours are considered as demand of hydropower generation. For

1 “Rencana Alokasi Air Tahunan (RAAT) Daerah Aliran Sungai (DAS) Brantas”

A2-7



Wonorejo and Tulungagung, and according to PT.PJB, the hydropower operation hours are

not set since the hydropower operation hours are not assigned to these hydropower stations.

The hydropower operation hours and corresponding hydropower discharge is shown in

Table 5.3.1.

Table A2.3.1 Hydropower Operation Hours and Discharge

Source: RAAT

A2.3.4 Priority of Water Demand

Priority of the demand is set as follows;

1) Municipal and Industrial

2) Irrigation

3) Hydropower

The order of the above demand corresponds to the order of the priority, hence the municipal

and industrial water demand is the highest in priority for allocation of water.

A2.4 Environmental Flow Requirement

The environmental flow is a minimum flow rate of the river that enable to sustains the

ecosystem soundness and human livelihood along the river. In Indonesia, the environmental

flow is required to keep 95% of the discharge of the flow duration.

In the water balance study of the Brantas River, the environmental flow requirement is set

at 95% of flow duration of the stream record at upstream, midstream and downstream of

the Brantas River. The environmental flow is assigned to the downstream of Sutami,

Mrican and New Lengkong. The average of the flow duration of these points are calculated

from the stream flow record from 2003 to 2012 as shown in Table A2.4.1. The 95%

1~10~20~ Sengguruh Sutami Wlingi Lodoyo Selorejo Sengguruh Sutami Wlingi Lodoyo Selorejo

1 24.0 24.0 20.5 24.0 24.0 55.3 66.6 90.1 57.5 9.3

2 24.0 24.0 22.5 24.0 24.0 53.8 71.8 94.4 57.5 9.53 24.0 24.0 23.5 24.0 24.0 59.7 75.1 96.6 57.5 9.51 24.0 24.0 24.0 24.0 24.0 57.8 75.2 101.1 57.5 12.02 24.0 24.0 24.0 24.0 24.0 55.3 75.0 99.4 57.5 12.03 24.0 24.0 24.0 24.0 24.0 53.8 94.4 129.3 57.5 12.51 24.0 24.0 24.0 24.0 24.0 74.7 102.9 137.4 57.5 13.52 24.0 24.0 24.0 24.0 24.0 71.1 97.9 126.7 57.5 13.53 24.0 24.0 24.0 24.0 24.0 66.6 93.0 120.2 57.5 13.51 24.0 24.0 24.0 24.0 24.0 73.8 100.5 128.5 57.5 13.02 24.0 24.0 24.0 24.0 24.0 71.5 106.1 139.1 57.5 13.03 24.0 24.0 24.0 24.0 24.0 71.5 106.3 137.1 57.5 13.01 24.0 24.0 24.0 24.0 24.0 74.9 107.1 139.5 57.5 12.52 24.0 24.0 24.0 24.0 24.0 77.8 114.1 144.2 57.5 12.03 24.0 24.0 24.0 24.0 24.0 61.9 86.3 110.2 57.5 11.51 20.0 24.0 22.8 24.0 24.0 56.5 77.1 95.2 57.5 10.02 14.0 24.0 14.4 24.0 24.0 48.7 66.1 76.9 57.5 9.63 11.0 24.0 8.5 24.0 24.0 43.8 55.6 63.9 57.5 9.61 8.0 24.0 7.4 24.0 24.0 40.0 57.2 61.5 57.5 9.52 7.0 24.0 7.1 24.0 24.0 38.4 57.2 60.8 57.5 9.13 5.0 24.0 5.0 24.0 24.0 34.4 49.6 51.0 57.5 9.11 5.0 24.0 5.0 24.0 24.0 30.8 45.6 47.0 57.5 9.02 5.0 24.0 5.0 24.0 24.0 29.8 48.3 47.6 57.5 9.03 5.0 24.0 5.0 24.0 24.0 27.8 48.5 47.2 57.5 9.01 5.0 24.0 5.0 24.0 24.0 25.4 45.7 43.7 55.6 9.02 5.0 24.0 5.0 24.0 24.0 23.9 48.5 45.7 57.5 9.03 5.0 24.0 5.0 24.0 24.0 23.0 51.4 49.2 57.5 9.01 5.0 24.0 5.0 24.0 24.0 21.6 45.3 45.1 55.9 8.52 5.0 24.0 5.0 24.0 24.0 20.3 48.0 47.0 57.5 8.53 5.0 24.0 5.0 24.0 24.0 20.2 44.7 44.0 54.7 8.51 5.0 24.0 5.0 24.0 24.0 20.8 44.7 44.9 55.4 8.52 5.0 24.0 5.0 24.0 24.0 22.7 48.8 52.7 57.5 8.53 5.0 24.0 5.0 24.0 24.0 21.8 47.9 55.3 57.5 8.51 6.0 24.0 9.5 24.0 24.0 27.8 54.3 66.1 57.5 8.52 24.0 24.0 21.8 24.0 24.0 49.3 81.7 93.1 57.5 9.03 21.0 24.0 21.1 24.0 24.0 45.6 74.1 91.5 57.5 9.0

MonthOperation Hours (Hours) Discharge for Hydropower Generation (m3/s)

OCT

NOV

AUG

SEP

JUN

JUL

APR

MAY

FEB

MAR

DEC

JAN

A2-8



discharge is assigned as environmental flow requirements at these points as shown in Table

A2.4.2.

Table A2.4.1 Flow Duration of the Stream Flow at Sutami, Mrican and New Lengkong from

2003 to 2012 (m3/s)

Exceedance

Percent Sutami Mrican New Lengkong

0% 892.0 1,174.0 1,285.5

5% 152.2 362.0 569.8

10% 133.7 306.9 445.6

15% 123.3 270.6 378.7

20% 112.8 241.6 322.4

25% 102.4 215.6 276.2

30% 92.3 191.9 236.6

35% 83.3 166.1 198.3

40% 75.8 143.6 165.2

45% 68.9 124.4 132.6

50% 62.0 109.1 105.5

55% 55.8 96.2 83.6

60% 50.6 84.7 65.9

65% 46.7 77.2 53.4

70% 43.6 72.4 45.3

75% 41.0 68.3 41.1

80% 38.4 64.9 37.7

85% 35.7 61.6 35.7

90% 33.2 57.7 33.9

95% 29.9 54.1 32.1

100% 22.5 24.5 22.6 Source: PJT-1

Table A2.4.2 Assigned Environmental Flow at Sutami, Mrican and New Lengkong

Assigned Location Sutami Mrican New Lengkong

Env. Flow (m3/s) 22.9 54.1 32.1 Source: JICA Project Team 2

A2.5 Hydraulics of Connecting Tunnel between Sutami and Lahor Reservoir

The Lahor and Sutami reservoirs are connected via connecting tunnel. The connecting

tunnel is a pressure type tunnel with concrete lined circular shape having inner diameter of

3.6 meter. The length of the tunnel is 498 meter and the elevation of the sill is EL.247 meter.

No inclination of the bottom invert of the tunnel is provided. The inlet of the connecting

tunnel in the Lahor reservoir was placed along the existing river and excavated to the

current foundation level. The inlet/outlet of the connecting tunnel in the Sutami reservoir

was placed at the steep slope in the reservoir.

A2-9



The drawing of the connecting tunnel is shown in Figure 2.5.1 with photos taken during the

construction period.

Source: Nippon Koei, History of Indonesia “3K” projects

Figure A2.5.1 Connecting Tunnel Alignment and Photos in Construction Stage

The discharge capacity of the connecting tunnel is estimated by the theory of Bernoulli's

principle, and the capacity varies dependent on the roughness of coefficient of the tunnel

lining. The relation of the water level difference and the discharge through the connecting

tunnel is expressed by the following equations.

dH |𝑊𝐿 𝑊𝐿 | 𝑓𝑉2𝑔

𝑓 𝐿𝑉

2𝑔𝐷

𝑓 12.7𝑔𝑛 𝐷 /⁄

Connecting tunnel

Approach Channel Connecting Tunnel

Approach Channel

Lahor Reservoir

Sutami Reservoir

Lining Works of Connecting Tunnel Approach Channel in Lahor Reservoir

EL 247m EL 247m

A2-10



Where, dH (m) is the difference of the water level between Lahor and Sutami reservoir,

WLSutami (EL.m) is the water level of the Sutami reservoir, WLLahor (EL.m) is the water level

of the Lahor reservoir, f1 is the head loss coefficient for inlet, V1 (m/s) is the velocity at

inlet, f2 is a friction coefficient, L (m) is the length of the connecting tunnel, D (m) is inner

diameter of the connecting tunnel. n is Manning’s roughness of coefficient. The Manning’s

roughness of coefficient ranges from 0.013 to 0.016. The discharge rating curve for the

Manning’s roughness of coefficient for n = 0.013, 0.0145, and 0.016 are shown in Figure

A2.5.2.


Figure A2.5.2 Discharge Rating Curve for Manning’s Roughness Coefficient of n = 0.013, 0.0145

and 0.016

For example, if the water level of Lahor reservoir is EL. 270 m and that of Sutami reservoir

is EL. 265 m, then the difference of the water level of “dH” is 5 meters. In the case, around

45 m3/s to 55m3/s flows from Lahor reservoir to Sutami reservoir through the connecting

tunnel. The water will flow to Sutami reservoir until the water level of the two reservoir is

the same.

For the water balance study, the hydraulic function of the connecting tunnel is embedded

in the water balance simulation model. The rating curve for Manning’s roughness of

“0.0145” shown in Figure A2.5.2 is employed.

A2.6 Other Assumptions of Water Balance Analysis

The assumption of water balance analysis for the Brantas River Basin is as follows;

1) Return flow of the irrigation and domestic demand is referred to values empirically

employed. The ratio of return flow to the water supplied is assumed to be 0.3 and 0.5

for irrigation and domestic demand respectively.

2) The evaporation height of the reservoir is assumed to 2 mm/day.

A2.7 Network Flow Diagram

The schematic diagram of the stream flow of the Brantas River Basin is shown in

Figure.A2.7.1.

Manning’s roughness

A2-11




Fig

ure

A2.

7.1

Bas

in D

iagr

am in

th

e B

ran

tas

Riv

er B

asin

for

Wat

er B

alan

ce (

1/2)

A2-12




Fig

ure

A2.

7.1

Bas

in D

iagr

am in

th

e B

ran

tas

Riv

er B

asin

for

Wat

er B

alan

ce (

2/2)

A2-13



A2.8 Water Balance Calculation Model

The water balance model of the Brantas River is developed and simulated through computer

based water balance simulation model called MODSIM. MODSIM is a generalized water

balance simulation software program developed in Colorado State University, and the

software has been widely applied for water resource management projects in the world.

The water balance simulation model of the Brantas River basin developed on MODSIM

and the model is shown in Figure A2.8.1.


Figure A2.8.1 Water Balance Simulation Model of the Brantas River Basin

Flow Direction

Legend

A2-14



CALIBRATION OF MODEL

A3.1 Calibration of Time Lag

The time lag (Tl) is the time of the flow travelling the channel and is calculated by the

following equation.

Tl𝐿𝑉

Where, L : length of channel (m)

V : velocity of the flow (m/s)

The velocity of the flow (V) is calculated by the following Manning’s equation;

V𝑅 / 𝑖 /

𝑛

Where, V : velocity of the flow (m/s)

R : hydraulic radius (m)

i : channel slope

n : Manning’s roughness of coefficient

The lag time of the channel from the upstream to the downstream of the Brantas River is

shown in the table below.

Table A3.1.1 Calculation of Time Lag of Flow

WS No. Length (km) Slope Qave (cms)Width

(m)n A (m2) S (m) R (m) v (m/s) w TL (hr)

1 180 23.7 215 39 40 0.035 27.1 42 0.6 1.5 2.4 2.7

2 178 4.5 299 41 60 0.035 35.8 62 0.6 1.1 1.9 0.7

3 176 3.6 212 63 70 0.035 44.3 72 0.6 1.4 2.4 0.4

4 172 10.0 204 80 50 0.035 44.3 52 0.9 1.8 3.0 0.9

5 168 7.4 190 94 50 0.035 47.8 52 0.9 2.0 3.3 0.6

6 164 2.5 139 98 50 0.035 44.9 52 0.9 2.2 3.7 0.2

7 162 1.5 750 106 50 0.035 77.5 52 1.5 1.4 2.3 0.2

8 154 6.2 477 123 60 0.035 79.8 62 1.3 1.5 2.6 0.7

9 281 7.1 374 129 60 0.035 75.8 62 1.2 1.7 2.8 0.7

10 279 5.2 433 134 60 0.035 81.2 62 1.3 1.6 2.7 0.5

11 150 6.0 667 139 60 0.035 94.9 62 1.5 1.5 2.4 0.7

12 148 5.9 738 144 70 0.035 105.5 72 1.5 1.4 2.3 0.7

13 144 10.0 500 148 70 0.035 96.1 72 1.3 1.5 2.6 1.1

14 140 2.0 2,000 150 70 0.035 147.1 72 2.0 1.0 1.7 0.3

15 136 10.4 743 155 70 0.035 110.6 72 1.5 1.4 2.3 1.2

16 132 2.3 575 157 70 0.035 103.8 72 1.4 1.5 2.5 0.3

17 92 9.5 2,375 192 70 0.035 177.9 72 2.5 1.1 1.8 1.5

18 88 5.6 1,400 195 70 0.035 154.6 72 2.1 1.3 2.1 0.7

19 86 10.6 1,178 204 70 0.035 149.5 72 2.1 1.4 2.3 1.3

20 80 6.9 690 210 80 0.035 137.6 82 1.7 1.5 2.6 0.7

21 74 5.6 800 216 70 0.035 138.9 72 1.9 1.6 2.6 0.6

22 72 5.3 2,650 218 80 0.035 209.0 82 2.5 1.0 1.7 0.9

23 70 2.5 625 225 80 0.035 138.4 82 1.7 1.6 2.7 0.3

24 68 4.9 2,450 228 80 0.035 209.6 82 2.6 1.1 1.8 0.8

25 66 8.5 1,700 231 90 0.035 198.3 92 2.2 1.2 1.9 1.2

26 64 6.2 2,067 253 90 0.035 224.3 92 2.4 1.1 1.9 0.9

27 26 5.5 2,750 303 90 0.035 272.1 92 3.0 1.1 1.9 0.8

28 276 19.0 2,111 308 120 0.035 281.4 122 2.3 1.1 1.8 2.9

29 18 12.0 1,714 309 120 0.035 265.1 122 2.2 1.2 1.9 1.7

30 16 2.0 2,000 328 120 0.035 290.4 122 2.4 1.1 1.9 0.3

31 275 6.4 2,133 340 120 0.035 302.4 122 2.5 1.1 1.9 0.9

A3-1



*”WS” is the number of sub basins for the Brantas river basin assigned by the Component-1 team. Source: JICA Project Team 2

The sum of Tl is 27.5 hours, so the river water of the Brantas River runs from its origin to

its estuary for a day.

The lag time is assigned in the water balance model built on MODSIM.

A3.2 Calibration with Actual Record

The water balance model by MODSIM of the present conditions is calibrated with the

actual recorded stream flow record to confirm that the model able to reproduce the actual

river flow in the model. In this calibration, the reservoir operation of the existing reservoirs

is set to the same with the actual operation, and the irrigation water supply is the same with

the actual supply to the existing irrigation area. Then the simulation result and actual flow

records are compared at Senggruh, Sutami, Mrican and New Lengkong sites as shown in

Figure A3.2.1.

a. Sengguruh


b. Sutami


c. Mrican


0

100

200

300

400

500

600

700

Discharge

(cm

s)

Year / Month

Record

Simulated

0

100

200

300

400

500

600

700

800

900

1,000

Discharge

(cm

s)

Year / Month

Record

Simulated

0

100

200

300

400

500

600

700

800

900

1,000

2006

/01

2006

/02

2006

/03

2006

/04

2006

/05

2006

/06

2006

/07

2006

/08

2006

/09

2006

/10

2006

/11

2006

/12

2007

/01

2007

/02

2007

/03

2007

/04

2007

/05

2007

/06

2007

/07

2007

/08

2007

/09

2007

/10

2007

/11

2007

/12

2008

/01

2008

/02

2008

/03

2008

/04

2008

/05

2008

/06

2008

/07

2008

/08

2008

/09

2008

/10

2008

/11

2008

/12

2009

/01

2009

/02

2009

/03

2009

/04

2009

/05

2009

/06

2009

/07

2009

/08

2009

/09

2009

/10

2009

/11

2009

/12

2010

/01

2010

/02

2010

/03

2010

/04

2010

/05

2010

/06

2010

/07

2010

/08

2010

/09

2010

/10

2010

/11

2010

/12

Discharge

(cm

s)

Year / Month

Record

Simulated

A3-2



d. New Lengkong


Figure A3.2.1 Comparison of the Model Result with Actual Observation Record

As shown in the figure, the stream flow of the model and observed records are almost the

same for the section at Sengguruh, Sutami and Mrican. For New Lengkong site, the

observed flow is smaller than that of estimated flow by the model. There might be caused

by un-accounted water extraction by irrigator or for domestic water consumption. Those

un-accounted demand is assumed as a dummy demand in the model and put the demand in

upstream of New Lengkong weir. The simulated result with the dummy demand is shown

in Figure A3.2.2.


Figure A3.2.2 Comparison of the Model Result with Actual Observation Record

As shown in the figure, the flow in the low flow season is close the actual record flow.

0

100

200

300

400

500

600

700

800

900

1,000

Discharge

(cm

s)

Year / Month

Record

Simulated

0

100

200

300

400

500

600

700

800

900

1,000

Discharge

(cm

s)

Year / Month

Record

Simulated

Simulated with Dummy Demand

Simulated > Record

A3-3

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