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S REPUBLIC OF INDONESIA MINISTRY OF PUBLIC WORKS DIRECTORATE GENERAL OF HOUSING BUILDING PLANNING AND URBAN DEVELOPMENT (CIPTA KARYA)

MEDAN URBAN DEVELOPMENT, HOUSING, WATER SUPPLY AND SANITATION PROJECT

VOLUME V MASTER PLAN AND FIRST STAGE PROGRAM FOR WATER SUPPLY AND SANITATION

PART 3- MASTER PLAN AND FIRST STAGE PROGRAM FOR DRAINAGE

OCTOBER 1980

ENGINEERING-SCIENCE, INC. SINOTECH ENGINEERING CONSULTANTS, INC. A JOINT VENTURE in association with PADCO and P.T. DACREA PREFACE

The feasibility reports emanating from the Medan Urban Development,

Housing, Water Supply and Sanitation Project were submitted in draft form to the Government of Indonesia (GOI) in February 1980. These reports, together with the earlier master plan reports, were reviewed by GOI In July 1980 and discussed with the Consultant at a series of meetings at that time. The outcome of this review process was that certain changes in content and format were agreed. These changes have been incorporated into the final printed reports.

A result of adopting the new guidelines provided by GOI is that differences occur between the Repelita III investments proposed in the master plan studies and those contained in the first stage program recommendations. The latter incorporate the final adjustments and represent the recommended program for Repelita III.

iii TABLE OF CONTENTS

LIST OF FIGURES

LIST OF TABLES

ORGANIZATION OF PROJECT REPORTS

LIST OF ABBREVIATIONS

SECTION 1 INTRODUCTION 1-1 1.1 AUTHORIZATION 1-i 1.2 OBJECTIVES OF THE PROJECT 1-1 1.3 SCOPE OF WORK 1-2 1.4 THE STUDY AREA 1-2 1.4.1 Description 1-2 1.4.2 Topography 1-4 1.4.3 Climate 1-9 1.4.4 Soils 1-9

SECTION 2 EXISTING DRAINAGE SYSTEM 2-1 2.1 DESCRIPTION OF THE SYSTEM 2-1 2.1.1 Drainage Channels 2-1 2.1.2 Rivers 2-1 2.2 FLOODING EXPERIENCE 2-2 2.3 DRAINAGE SYSTEM DEFICIENCIES 2-2 2.4 RIVER CROSS-SECTION MEASUREMENT AND PROFILES 2-8 2.5 ESTIMATED EXISTING CAPACITY 2-8

SECTION 3 PROJECTED STORMWATER FLOWS 3-1 3.1 GENERAL 3-1 3.2 RAINFALL CHARACTERISTICS 3-1 3.3 RAINFALL DATA 3-2 3.4 PROBABLE RAINFALL 3-3 3.5 RUNOFF ANALYSIS 3-3 3.6 RUNOFF RATES 3-5

SECTION 4 PUBLIC HEALTH 4-1 4.1 PRESENT CONDITIONS 4-1 4.2 DRAINAGE 4-3

V SECTION 5 DESIGN CRITERIA AND BASIC FOR COST ESTIMATES 5-1 5.1 INTRODUCTION 5-1 5.2 DESIGN CRITERIA 5-1 5.2.1 General Criteria 5-1 5.2.2 Hydraulic Design 5-1 5.2.3 Rivers 5-3 5.2.4 Major Channels 5-3 5.2.5 Local Drains 5-3 5.3 BASES FOR COST ESTIMATION 5-3 5.3.1 General Bases for Pricing 5-3 5.3.1.1 Price Contingencies. 5-7 5.3.1.2 Engineering Services 5-7 5.3.1.3 Physical Contingencies 5-7 5.3.2 Drainage System 5-8 5.3.2.1 River Channel Improvements 5-8 5.3.2.2 Major Drains 5-8 5.3.2.3 Local Drains 5-8 5.3.2.4 Maintenance 5-8

SECTION 6 ALTERNATIVE DRAINAGE MANAGEMENT SYSTEMS 6-1 6.1 INTRODUCTION 6-1 6.2 ALTERNATIVE SERVICE AREAS AND SERVICE LEVELS 6-1 6.3 ALTERNATIVE FORMS OF FLOOD CONTROL 6-2 6.3.1 Reduction of Flood Runoff 6-2 6.3.2 Improved Inlet 6-5 6.3.3 Increased Channel Capacity 6-5 6.3.4 Avoidance and Mitigation of Flood Damage 6-6 6.3.5 Control of Other Features 6-6 6.4 EVALUATION OF ALTERNATIVE DRAINAGE SYSTEM IMFROVMErNT 6-6 6.4.1 Major River Channels 6-7 6.4.1.1 Lower Deli River 6-7 6.4.1.2 Upper Deli River 6-8 6.4.1.3 Babura River 6-8 6.4.1.4 Belawan River 6-12 6.4.1.5 Percut River 6-12 6.4.2 Major Drains 6-12 6.4.2.1 Kera River 6-12 6.4.2.2 Sikambing River 6-16 6.4.2.3 Putih River 6-16 6.4.2.4 Badra River 6-19 6.4.3 Local Drainage Works 6-19 6.4.3.1 Local Drains 6-19 6.4.4 Summary 6-20

SECTION 7 RECOMMENDED DRAINAGE MANAGEMENT SYSTEM 7-1 7.1 DESCRIPTION OF RECOMMENDED SYSTEM 7-1 7.1.1 General 7-1 7.1.2 Description of Recommended System 7-2

vi 7.2 OPERATIONS AND MAINTENANCE 7-2 7.2.1 System Operation 7-2 7.2.2 Monitoring 7-2 7.2.2.1 Flow Recording and Inundation Records 7-2 7.2.2.2 Channel and Drain Maintenance 7-6 7.3 PHASED IMPLEMENTATION PROGRAM 7-6 7.4 COSTS 7-6

SECTION 8 ORGANIZATION AND FINANCE 8-1 8.1 EXISTING ORGANIZATION 8-1 8.2 RECOMMENDED ORGANIZATION 8-1 8.3 REVENUE AND EXPENDITURE 8-5 8.3.1 Existing Levels 8-5 8.3.1.1 Taxes 8-6 8.3.1.2 Expenditure 8-7 8.3.2 Future Requirements 8-7 8.3.2.1 Tax Revenue Required 8-7 8.3.2.2 Summary 8-9

SECTION 9 THE RECOMMENDED FIRST STAGE DRAINAGE SYSTEM IMPROVEMENT PROJECT 9-1 9.1 GENERAL 9-1 9.2 DESCRIPTION OF THE FIRST STAGE DRAINAGE SYSTEM IMPROVEMENT PROJECT 9-2 9.2.1 Kera Basin Improvements 9-2 9.2.1.1 Main Drains 9-2 9.2.1.2 Submain Drains 9-16 9.2.1.3 Local Drains 9-16 9.2.2 Urban Area Channel Clearing Cleaning and Dredging 9-16 9.2.2.1 River Channels 9-16 9.2.2.2 Main Drains 9-16 9.2.2.3 Submain Drains 9-31 9.2.2.4 Local Drains 9-31 9.2.2.5 Summary 9-31 9.2.3 Monitoring 9-31 9.2.3.1 Flow Recording and inundation Records 9-31 9.2.3.2 Channel and Drain Maintenance 9-31 9.2.4 Other Drainage Improvements 9-33 9.2.5 Flood Warning and Emergency Assistance 9-33 9.3 SOCIAL AND ENVIRONMENTAL CONSIDERATIONS 9-33 9.3.1 Population Served 9-33 9.4 ECONOMIC CONSIDERATIONS 9-41 9.5 OPERATION AND MAINTENANCE 9-41 9.5.1 Organization 9-41 9.5.2 Staffing Requirements 9-43 9.5.3 Training Programs 9-44

vii 9.6 ESTIMATED COST AND RECOMMENDED IMPLEMENTATION SCHEDULE 9.6.1 Capital Costs 9.6.2 Operations and Maintenance Costs 9.6.3 Implementation Schedule

SECTION 10 ECONOMIC AND FINANCIAL ANALYSIS OF FIRST STAGE PROGRAM 10-1 10.1 INTRODUCTION 10-1 10.2 PROJECT COSTS 10-1 10.2.1 Capital Costs 10-1 10.2.2 Foreign Exchange Costs 10-3 10.2.3 Operation and Maintenance Costs 10-3 10.3 PROJECT FUNDING 10-3 10.3.1 General Approach to Funding MUDS Program 10-3 10.3.2 Drainage Funding 10-6 10.4 FINANCIAL EVALUATION 10-7 10.4.1 Introduction 10-7 10.4.2 Financial Assumptions 10-7 10.4.2.1 Income Statement 10-7 10.4.2.2 Balance Sheet and Flow of Funds 10-7 10.4.3 Financial Evaluation 10-12 10.5 ECONOMIC EVALUATION 10-12 10.5.1 Introduction 10-12 10.5.2 Benefits of Proposed Investments 10-12 10.5.2.1 Flood Control 10-12 10.5.2.2 Health Benefits 10-13 10.5.2.3 Environmental Benefits 10-13 10.5.2.4 Capital Preservation 10-13 10.5.3 Summary 10-13

APPENDIX A EXISTING DRAINAGE SYSTEM A-i MAJOR CHANNEL CROSS-SECTIONS A-1 A-2 ESTIMATED CAPACITY OF MAIN CHANNELS A-15

APPENDIX B DRAINAGE CAPITAL COSTS: 1981/82 - 1983/84 B-I LIST OF FIGURES

Page

1.1 Study Area Location 1-3 1.2 The Medan Region 1-5 1.3 Generalized Contour Map of the Study Area 1-7 2.1 Existing Combined Drainage System and Combined Sewerage System 2-3 2.2 Principal Catchments and Sub Drainage Areas 2-5 2.3 Location of Flood Prone Areas 2-7 2.4 Profile of Deli River 2-9 2.5 Profile of Belawan River 2-10 2.6 Profile of Percut River 2-11 3.1 Rainfall Intensity - Duration Curves 3-4 3.2 Runoff Coeficients as a Function of Rainfall Duration and Percentage of Impervious Area 3-6 3.3 Fraction of Impervious Area for Existing and Future Conditions 3-7 5.1 Typical Lined Channels 5-4 5.2 Typical Local Drains 5-5 5.3 Construction Costs for Lined Open Channels 5-9 5.4 Excavation Costs for Unlined Open Channels 5-10 5.5 Cost of Lining Existing Unlined Open Channels 5-11 5.6 Cost of Box Culverts 5-12 6.1 Drainage Service Areas 6-3 6.2 Projected Storm Runoff for Deli River Basin 6-9 6.3 Projected Storm Runoff for Babura River Basin 6-11 6.4 Projected Storm Runoff for Percut River Basin 6-13 6.5 Projected Storm Runoff for Kera River Basin 6-14 6.6 Typical Comparative Costs of Main Drains 6-15 6.7 Projected Storm Runoff for Sikambing River Basin 6-17 6.8 Projected Storm Runoff for Putih River Basin 6-18 6.9 Proposed Local Submain Drains 6-21 6.10 Typical Comparative Capital Costs - Local Drains 6-23 7.1 Drainage Implementation Schedule 7-7 8.1 Former Organization Chart Drainage Section 8-2 8.2 Existing Organization Chart Drainage 8-3 8.3 Proposed Organization Chart Drainage Section 8-4

ix 9.1 Location of Flood Prone Areas 9-3 9.2 Drainage Service Areas 9-9 9.3 Drainage Service Objectives 9-11 9.4 Existing Drainage System in Kera Basin 9-13 9.5 Projected Storm Runoff for Kera River Basin 9-15 9.6 Proposed Drainage System 9-19 9.7 Typical Cross Section Kera Main Channel 9-21 9.8 Typical Cross Section Service Level 1 9-28 9.9 Typical Channel Cross Section Service Level 3 9-29 9.10 Typical Cross Sections of Street and Footpath Drains 9-30 9.11 Comparative Cost of Labor Intensive Methods 9-42 9.12 Drainage Implementation Schedule 9-50

A.1 Existing Main Channel Cross-Sections A-3 A.2 Existing Main Channel Cross-Sections A-5 A.3 Existing Main Channel Cross-Sectiens A-7 A.4 Existing Main Channel Cross-Sections A-9 A.5 Existing Main Channel Cross-Sections A-11 A.6 Existing Main Channel Cross-Sections A-13

x LIST OF TABLES

4.1 Incidence of Reported Enteric Diseases in 1978 4-2 5.1 General Materials and Labor Costs 5-6 6.1 Drainage Management System - Service Objectives 6-24 7.1 Application of Service Objectives 7-3 7.2 Estimated Capital Costs for Recommended Drainage Management System 7-8 7.3 Estimated Operation and Maintenance Costs for Recommended Drainage Management System 7-9 8.1 Drainage - Revenue and Expenditure, 1978/79 8-6 8.2 Annual Tax Revenue Required (Rp. Million) to cover Recurrent Costs, Interest and Capital Repayments in Constant 1979 Prices 8-8 8.3 Annual Tax Revenue Required (Rp. Million) to cover Recurrent Costs, Interest and Capital Repayments Assuming 10% Inflation, Expressed in 1979 Prices 8-8 9.1 Drainage Management System - Service Objectives 9-5 9.2 First Stage Drainage Program Summary 9-6 9.3 Kera Basin Schedule of Proposed Improvements Main Channel 9-17 9.4 Kera Basin Schedule of Proposed Improvements Submain Drains 9-22 9.5 Schedul! of Urban Area Channel Clearing, Cleaning and Dredging 9-32 9.6 Deli Drainage Area - Schedule of Other Drainage Improvements 9-34 9.7 Babura Drainage Area - Schedule of Other Drainage Improvements 9-38 9.8 Drainage Management System Population Served 1985 9-40 9-43 9.9 Staffing Requirements 9.10 Schedule of Capital Cost 9-45 9.11 Schedule of Capital Expenditure - Drainage Millions of Rupiah - 1st Jan 1980 Prices 9-48 9.12 Annual Operations and Maintenance Costs - 1985 9-49

xi 10.1 Drainage Capital Costs - First Stage Program 10-2 10.2 Projection of Kotamadya Medan's Contribution to MUDS Programs 10-5 10.3 Drainage - Projected Income Statement Rp. Million in Current Prices 10-8 10.4 Drainage - Projected Flow of Funds Statement Rp. Million in Current Prices 10-9 10.5 Drainage - Projected Balance Sheet Rp. Million in Current Prices 10-10

A-2.1 Estimated Capacity of Existing Main Channels (with Freeboard) A-17 A-2.2 Estimated Capacity of Existing Main Channels (without Freeboard) A-23

Drainage Capital Costs: 1981/82 1983/84 B-I

xii ORGANIZATION OF PROEJCT REPORTS

the The results of investigations carried out in connection with Project Medan Urban Development, Housing, Water Supply and Sanitation are contained in the following series of reports:

Inception Report for Long Term Urban Development Plan and Feasibility Study on First Stage Housing Development Project

Volume I Summary

Volume II Interim Strategic Plan and Feasibility Stud

Volume III Long Range Urban Development Plan

Volume IV Housing Development Program Part 1 - Housing Development Situation and Strategy Part 2 - Kampung Improvement Program Part 3 - Sites and Services / Low Cost Housing Program Supply Volume V Master Plan and First Stage Program for Water and Sanitation Part 1 - Master Plan and First Stage Program for Water Supply Part 2 - Master Plan and First Stage Program for Wastewater Part 3 - Master Plan and First Stage Program for Drainage Part 4 - Master Plan and First Stage Program for Solid Wastes

bound as Note: Parts 1-3 of Volume IV and Parts 1-4 of Volume V are separate report volumes. Appendices to Part 1, Volume V are also bound separately.

xiii LIST OF ABBREVIATIONS

ORGANIZATIONS

ADB Asian Development Bank DKKP Medan Solid Wastes Management Department KIP Kampung Improvement Program LCH Low Cost Housing MUDS Medan Urban Development Study SSCH Sites and Services and Core Housing UNDP United Nations Development Program USAID United State Agency for International Development

TECHNICAL

mm millimetre mg milligram m metre g gram km kilometre kg kilogram sq m square metre t tonne (metric) ha hectare sq km square kilometre BOD 5-day, biochemical oxygen demand 1 litre TDS Total dissolved solids cu m cubic metre ES Electrical conductivity TU Turbidity units s second DO Dissolved oxygen min minute d day TDH Total dynamic head y year LS Lump sum ea each m/s metres per second na not available or not known 1/mmn litres per minute cu m/s cubic metres per second Rp Indonesian Rupiah cu m/d cubic metres per day mg/l milligrams per litre i/c.d litres per capita per day

xv SECTION 1

INTRODUCTION

1.1 AUTHORIZATION

On 12 October 1978, an agreement was signed by the Government of Indonesia, Ministry of Public Works, Directorate General of Housing Building Planning, and Engineering Science, Inc., for consulting services in connection with the Medan Urban Development Housing, Water Supply, and Sanitation Project. The project was financed under the terms of a loan to the Government of Indonesia from the United States of America 28 Agency for International Development (AID loan no.497-T-G40, dated Inc. July 1976). Engineering Science, Inc. and Sinotech Consultants, and a joint venture, carried out the work in association with Planning Development Collaborative International and P.T. Dacrea. Additional architectural expertise was provided to the project from P.T. Perencana Jaya through subcontractual arrangement with P.T. Dacrea.

1.2 OBJECTIVES OF THE PROJECT

The long range objective of the Project is to assist the Governwent of Indonesia in directing the long term urban development of Medan, particularly with regard to: (1) the construction of new and improvement of existing urban settlements within the context of the governments Kampung Improvement (KIP), Sites and Services and Core Housing (SSCH), and Low Cost Housing (LCH) programs; and, (2) improvement and expansion of water supply, sewerage, drainage, and solid waste disposal systems.

The immediate objective of the Project is to assist the Government in the preparation of a Long-Term Urban Development Plan for Medan up to the year 2000 and to assist the government in preparing a Feasibility Study for a First Stage Housing Development Project which will permit appropriate investment decisions.

The Housing Development Feasibility Study is aimed at assisting the Government, as part of the Long-Term Urban Development Plan, to formulate a well defined first stage housing development project which will be be ready for investment decisions. The first stage housing project will designed to achieve an optimum balance between the City's short term needs on the one hand and resources, local capability and socio economic aspects on the other, with due consideration of financial and economic benefits.

1-1 Another major objective is to develop, as part of the overall urban improvement program for the City of Medan, long-range Master Plans through the year 2000 for water supply, wastewater, drainage and solid waste systems which will assist Government in the management, operation, and financing those systems.

Feasibility Studies for the first stage development of the Master Plan are to include economic and technical evaluations of projects suitable and complete enough in detail to enable a consultant to proceed directly into final design and thereby allow the Government to obtain construction financing from an international or bilateral lending agency such as the World Bank, the Asian Development Bank, or AID.

1.3 SCOPE OF WORK

The scope of work is divided into five major components as follows:

1. Preparation of a long term urban development plan.

2. Preparation of a feasibility study for housing develcpment projects including a Kampung Improvement Programme and a Sites and Services and Low Cost Housing Scheme.

3. Develop long-range Master Plans for water supply, wastewater, drainage and solid wastes systems in the study area through the year 2000.

4. Prepare First Stage Feasibility Studies for water supply, wastewater, drainage and solid wastes systems to meet needs through the year 1990.

5. Carry out detailed engineering for the First Stage Sites and Services Scheme and the Low Cost Housing Scheme.

In addition, In-Service Professional Training Programs shall be conducted.

1.4 THE STUDY AREA

1.4.1 Description

Medan is located on the coastal plain of North Sumatra between the Malacca Straits and a range of volcanic mountains which run roughly north-west to south-east throughout the island of Sumatra. Geographic proximity to the major neighbouring cities such as Kuala Lumpur and Singapore gives the city an international character in terms of trading business (see Figure 1.1).

Medan and Belawan port are the hub for an entire region which extends beyond the provincial boundaries of North Sumatra to include Aceh, Riau and parts of West Sumatra (see Figure 1.2).

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The city has a population of approximately 1.2 million people and is the fourth largest city in the country. The total land area of the city is 26,500 hectares, divided into eleven political districts called Kecamatans. Geographically, the urban form of the city is rather irre gular. Urban development has occurred mainly around the central area of Medan. Except in the oldest portions of the city, housing is primarily single storey and of relatively low density. In the oldest portion of the city, densities are much higher, consisting largely of three or four storey walk-up flats, with shops and businesses located on the ground floor. Growth trends are visible outside the city boundaries with village development parallelling the banks of rivers. Rivers and rail road alignments contain a small amount of high density informal housing for very low income groups. The rest of the city's area is made up of agricultural land, including tobacco and coconut plantations, rice paddie and swamp.

1.4.2 Topography

The study area lies between sea level and about 55 metres above sea level, on the northern end of regional basins which continue upward to the crest of the Barisan range (2000 metres in elevation) near Brastagi, 60 kilometres to the south. General contours for the study area are presented in Figure 1.3.

The northern end of the study area is in a coastal tidal zone which lies below 2.5 metres elevation. This zone is about seven kilo metres wide in a north-south direction. The coastal plain lies above the zone of tidal influence and extends for about eight kilometres up to about 15 metres elevation. The plain is relatively low, poorly drained ground.

Above 15 metres elevation, the land is better drained and under lain by consolidated bedrock or more developed soils. This portion of the study area covers a zone about 12 kilometres wide (north-south) between 15 and 35 metres elevation. South of Medan, the land begins to rise as a series of low hills followed by broad ridges. From about 70 metres elevation, the hills and ridges gradually narrow and the flat valley floors shrink. At 300 metres elevation, the terrain consists of steep slopes between ridges and streams' This terrain has occasional broad ridges, particularly above 700 metres. The ridges and peaks of the Barisan Mountains separate the Belawan-Deli-Percut basin from the Brastagi basin.

Relief and gradients within the study area are generally small although some steep slopes of 5 to 10 percent may be found along rivers and low ridges on the southern margin of the study area. Most slopes

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IN and river gradients are less than 0.4 percent within heavily urbanized areas and 0.1 to 0.2 percent in the coastal plain and tidal zones. Interpretations of 2.5 metre contour maps indicate somewhat steeper slopes on the east side of the Deli between 5 and 12.5 metres elevation and between 15 and 25 metres elevation. Numerous benches (wide, rela tively gentle terrain) are located in the southwestern and southeastern sectors of the study area above 25 metres while very small benches lie among the steep valley and ravines in the south central sector. Above 50 metres elevation, wide ridges or benches are separated from the lower benches but many of these join in the Belawan River valley in the southwestern sector.

1.4.3 Climate

The equatorial location and low elevation of Medan largely determines the tropical climate of the region. Although rainfall, temperatures and sunshine show some seasonal periods, these seasons are not as distinctly marked as in Java and many other areas of Asia. Two rainy periods occur during the fall and spring rather than during the more typical "monsoon" seasons which occur over much of Asia. These rainy periods closely resemble those in southern India, Sri Lanka, and Equatorial Africa. Medan rainfall has been recorded since 1879 at three stations. During the period of record annual rainfall has varied from 1,352 to 2,873 mm with 10 percent of the years having rainfall above 2,400 mm and 10 percent below 1,600 mm. About 80 percent of the annual rainfall ranged from 2,000 to 2,400 mm, and the average annual rainfall for 40 years was about 2,050 mm. Distribution of rainfall throughout the year shows two high rain months: October and May, although the longer "rainy season" extends from September to January. Eighty percent of the months have rainfall between 60 and 300 mm, while about sixty percent have rainfalls of 300 to 400 mm.

Long term rainfall data for Medan indicated only three days with 250 to 290 mm of rain in 24 hours. Although these storms occurred in December or January, they occurred at widely different years: 1907, 1937, and 1956, and these storms coincide with high monthly rainfalls but not with highest rainfall years. Such scattered temporal distri bution indicates that the storms were of limited areal extent and period and that rainfall quickly decreased beyond the intense centre of rainfall.

Diurnal rainfall data shows a strong tendency towards afternoon and night rains and relatively dry morning periods. Records indicate that periods of 6 to 12 hours separate the rainy periods of each day and thereby allow runoff to occur before the next day's rains.

1.4.4 Soils

Soil type and relatively high groundwater levels have strongly influenced urban growth patterns and agricultural land uses in the study area. The general distribution of soils and groundwater tables may be separated into three zones: (1) coastal tidal zone, (2) coastal plain, and (3) piedmont. Within the coastal tidal zone, alluvial

1-9 soils are generally rich in organic material and clay and the water table is at or close to the ground surface.

Along the major rivers, some alluvial sands and gravels may be found and the water table is usually at the same level as the river. On the coastal plain, soils have developed on older alluvial deposits which are higher and somewhat coarser than those in thecoastal tidal zone. Better drainage allows the water table to drop to about 1.5 metres below ground surface, although localized water tables may be higher due to poor local drainage.

The highly organic and fine-grained sediments in the tidal zone requires substantial filling and extra foundation work in order to develop even the simplest structural uses. Some long-term subsidence or differential settlement could be expected even with special founda tion preparations. Most organic and fine-grained sediments and high soil moisture content form corrosive acid conditions with a high sul phate content.

Within the study area and general vicinity, eight differefit soil types in five elevation zones have been identified. In the coastal tidal zone, two alluvial soils are recognized: (1) grey humus soil of clay and grey alluvium phases and (2) grey hydromorph soils. The grey, brown and yellow-brown regosol and grey hydromorphic soils are most common on the coastal plains and lower hills. A brown andosol pn pre-Toba and a brown podosol on Toba volcanics extends from the Percut River to the north and south. Above the study area, a brown podosol extends from about 150 metres up to 400 metres, where it is replaced by a,brown..andosol developed on the volcanics which form the source for the Sibolangit springs. High moisture content increases the acidity in the clay soils and sediment derived from acid-volcanic bedrock. All soils are acidic and many are highly acidic; some have a high hydrogen sulfide content and are corrosive.

1-10 SECTION 2

EXISTING DRAINAGE SYSTEM

2.1 DESCRIPTION OF THE SYSTEM

Surface drainage in Medan is accomplished by a system of open channels and closed conduits which carry surface runoff, grey water from buildings and houses, and some wastewaters to flour rivers that run through the city. The system is, in many places, inadequate to handle the flows, and flooding is a common occurrence.

2.1.1 Drainage Channels

There are about 946 km of drainage channels in the study area. These can be classified as follows:

Type Total Length (km)

Open channel Fully concrete lined 550 Partially concrete lined 250 Unlined 122 922 Closed conduits 24 946

The channels range in size from the small channels that border each street in the urbanized area to major channels that discharge di rectly to a river. The major channels and the rivers are shown on Figure 2.1.

2.1.2 Rivers

The four major rivers that receive Medan's drainage are the Deli, the Kera, the Belawan, and the Percut. The catchment and sub-drainage areas drained by these rivers are shown on Figure 2.2.

Deli River: The Deli River, the most important drainage channel, runs through the central part of Medan Kotamadya. It has a length of about 80 km and has two principal tributaries, the Babura River and the Sikambing River. The Sikambing River also has a sub-tributary, the Putih River. The Bedra and Puluh Rivers also flow into the Deli in it's lower reaches. Flooding usually occurs annually in the downstream area. Slopes of these rivers vary from 0.038 to 0.357 percent in the study area. The river has a catchment area of about 400 sq km.

2-1 Kera River: The Kera River is a small stream in the northern por tion of the study area where it is the eastern boundary of the study area. It has been extended southerly with an open channel to connect with the Sulang-Saling River in the southern part of the study area. The water in the channel is grossly polluted with sewage, and its capa city is reduced by solid wastes dumped in the channel. About 4 km of the channel are masonry lined; the remainder is unlined earth embankment. The slope of the channel in the study area varies from 0.052 to 0.50 percent. The catchment area is about 140 sq km.

Belawan River: The Belawan River is located along the western boundary of the study area, with an average slope of 0.104 percent. Water in this river is still not seriously polluted. Its catchment area is about 285 sq km.

Percut River: The Percut River flows through the eastern part 0' the Medan Kotamadya. Its slope varies from 0.069 to 0.303 percent. Total length of the river is about 78 km, 42 km of which is in the study area. Its catchment area is about 210 sq km.

Coastal Tidal Zone: A broad band of low lying swampy area loosely connects the major rivers to the ocean.

2.2 FLOODING EXPERIENCE

Flooding is a serious problem in Medan. Whenever there is a heavy rain, roads and low-lying areas are flooded with consequent property damage, pollution of shallow wells, and traffic interference. No formal records are kept of flood depths or frequencies. However flooding of two metres or more in some areas is common. Major floods occurred in 1956, 1965 and 1971.

Figure 2.3 shows the areas most prone to flooding. It is based on a map of Kotamadya Medan prepared by Dinas Planologi Kotamadya Medan and on field inspections and interviews by the Project staff. Most of the flood prone areas occur along the length of the Deli River in the study area and along the Sikambing and Babura Rivers.

2.3 DRAINAGE SYSTEM DEFICIENCIES

The principal problem with the drainage system is insufficient capacity compounded by growths of weeds and the extensive dumping of refuse in the rivers and channels.

In the central city areas most of the inlets along the roads are too small to handle the flows, and they are often blocked with road sweepings or garbage. As a consequence, local flooding often occurs even after a relatively light rainfall.

Because of the flat topography, many drainage ditches have insu fficient slope to carry the runoff. Weeds and refuse further reduce their capacity resulting in more frequent flooding than would otherwise occur.

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41 F IGURE

t1 I PRINCIPAL CATCHMENTS AND p SUB DRAINAGE AREAS

LEGEND . STUDY AREA BUNOARY MAJOR DRAINAGE AREA BOUNDARY SUB DRAINAGE AREA " BOUNDARY

CATCHMENT AREA BOUNDARY KERA RIVE KE-' - ' -< RIVER, STREAM

I.- MAIN DRAINAGE CHANNEL

D / 'ELI DELI WATERSHED "ftwol.,,,, f CATCHMENT TOTAL WATER AREA WITHIN CATCHIENT A 4STUDY AREA in sq km t..i|Vft . In sq km

P~~ I SUB-DRAINAGE AREADESIGN

ENGINEERING-SCIENCE SIN 3mst Available Documenm" KIR

DOCU 4Vail . FIGURE 2.3 TOP.ImN

LOCATION '"F FLOOD PRONE AREAS

LEGEN - SITEU WERE UNLAR iFLNIINI KMI Hill scil

4444+44 RAIL MAI LiI- - EJliE WA

- 111DT AREA MiWAIT

ii ....- .... ,

".;.-". 'k TB

KL1.In Wi

ENGINEER ING-SCI ENCE - SINT[CI 10 Increased urbanization and the increase in paved, impervious areas has also contributed to the problem because of increased runoff.

The original design of drainage channels (width, depth, slope) was not adequate to handle present runoff loads. In a number of cases, the upstream portions of channels have been constructed but the downstream portions have not been improved. The result, of course, is the trans ference of flooding from the upstream area to a downstream area. Lack of channel lining in some sections is another cause of inadequate channel capacity.

The frequency and severity of flooding, particularly local flooding, could be reduced with improved operation and maintenance. Difficult as it may be to enforce, people should not use ditches, channels, or rivers for solid waste disposal (realistically, though, it will probably not be possible to improve this situation substantially until more satisfactory methods for solid waste collection and disposal are available). However, in the central areas, street sweepings and refuse should be removed from the drains regularly. Ditches and channels should be kept free of weeds and refuse. If this were done, flooding frequency and severity would be reduced. This would also improve channel velocities and reduce sediment deposition which also reduces channel capacity.

Adequate maintenance of the drainage system is not possible with the manpower and equipment presently available.

2.4 RIVER CROSS - SECTION MEASUREMENT AND PROFILES

To provide a basis for estimation of the rivers' flow capacities, cross-sections of the four rivers were measured at 50 locations during May 1979 (data for an additional 11 cross-sections on the downstream reaches of the Deli River were provided by DPU). All sections were measured at bridge crossings, and the locations of the section and the cross-section data are presented in Appendix A-I.

In general, the upstream portions of the rivers are narrow and relatively deep with rocky bottoms. The rivers are shallower and broader in the downstream reaches and have sandy silt bottoms. The streams are meandering, and the banks are lined with weeds and brush. The river velocities decrease with the decreasing slope from south to north. Generalized profiles of the rivers were derived from 1:50,000 scale topographical maps as illustrated in Figures 2.4, 2.5 and 2.6.

2.5 ESTIMATED EXISTING CAPACITY

Each of the four major rivers were divided into reaches defined by the cross-sections, and the flow capacity of each reach was calculated 2 using the Manning equation (Q = Ar2 73 Sl/ n -1). Values for the coefficient "n" were estimated during field surveys. The estimated capacities and values used in calculating them are shown in Appendix A-2.

2-9 FIGURE 2.4

a:L w E w-l > X

z > w U Li. 0 cJ m- w

0 oo 0n

0 w w z a.

6 6 6 0

sOJIDW ul 'NOIU.VA3

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH FIGURE 2.5

w E > .c z =

w w o- 0 00 0 0 C) o 0 z a. z

0w 00 0~0

D - (fl

0 0 00

sj04ow u! 'NOILVA313

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH" FIGURE 2.6

D 1r- E

LL I

ww 0L > a.a z

0 0 0 (Y.

o z

I I !

$946w u 'NOIIVA313

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH vp SECTION 3

PROJECTED STORMWATER FLOWS

3.1 GENERAL

Given the extremely limited amount of river flow measurement data currently available, all estimates of present or future stormwater flows must be made and used with some caution. The runoff rates presented here in were developed in order to provide a basis for estimating the probable cost of drainage system requirements over the study period. Full recog nition should be made of the relatively flimsy data upon which these estimates are based, and considerable care observed in making commitments to large channel modification projects before better data can be made available.

3.2 RAINFALL CHARACTERISTICS

The distribution of rainfall throughout the years shows two high rain months: October and May, although the long "rainy season" extends from September to January. Of the 935 months of rainfall records, 80 percent of the months have rainfall between 60 and 300 mm, while about eight percent have rainfalls from 300 to 400 mm and two percent (six months) had rainfalls greater than 400 mm per month.

The three stations in Medan had three different days with 250 to 290 mm of rain in 24 hours. Although these storms occurred in December or January, they occurred in widely different years: 1907, 1931, and 1956, and these storms coincidedwith high rainfall months (more than 300 mm storm) but not with highest rainfall years. Such temporal dis tribution indicates that the storms were of limited areal extent and period and that rainfall quickly decreased beyond the intense center of rain. Comparisons with twelve other northern North Sumatra Stations (below 50 m elevation) show average annual rainfall varied from 1,800 to 3,177 mm. Monthly averages for daily maxima varied from 26 to 85 mm, while storms of records ranged from 112-309 mm/during 10-20 years,. Most records showed the storms of 1/1931 and XI/1956 to have been most wide spread with limited local centers of high rainfall.

The rainfall daily maxima for Sibolangit were 130 to 140 mm and are similar to the secondary maxima in the more northern, lower stations.

3-1 ( This difference between primary maxima indicates that the very high rain fall came from local thunder-storms. A 1931 daily maximum at Binjei would further indicate that some frontal activity could produce widespread heavy rains. Diurnal rainfall shows a strong tendency towards afternoon and night rains and relatively dry morning periods. For a 15 year period, rainfall of more than 5 mm/h during January to September generally occurred between 12.00 to 01.00, while during the "rainy season" rains continued from 12.00 or 15.00 to 06.00 the next morning (adding 50 percent to the total period). rain These records indicate that periods of 6 to 12 hours separate daily rainy periods and thereby allow runoff and drainage before the next day's rains. Diurnal rain records also indicate that the higher hourly rainfalls of 16 to 30 mm most commonly occurred between 18.00 and 22.00 during March to September and between 23.00 and 01.00 during the rainy period of October to December. Maximum hourly rainfalls during January to March fell below 15 mm. Rainfall records for 1879 to 1941 have been summarized for 15 sections within the regional drainage basin of Medan (or the Deli Regency). These records clearly indicate an increase in annual rainfall with elevation:

Average Annual Rainfall Location Elevation (mam) _(m)

1,773-2,036 Mabar 6-12 2,065-2,269 Medan 28-38 2,298-3,098 Two rivers, Deli Tua 60-101 3,127-3,978 Petani 129-174 4,520 Sibolangit 565 5,279-6,676 Bandar Baru 864-928

A comparison of monthly rainfall at Sibolangit and Medan showed the same high rainfall during October and May, but in Sibolangit, the rainy period extended from August through May with more than 250 mm of rain per month. Rainfall in the river basins above Medan is generally higher because )f longer daily and seasonal rains rather than more intense rains.

3.3 RAINFALL DATA Rainfall data from 1941 to 1961 and 1953 to 1976 were obtained from the Hydrology Design Unit, Provincial Department of Public Works Medan. This data will be published in the near future.

3-2 3.4 PROBABLE RAWALL

Rainfall data have been analysed by the Hydrology Design Unit who have prepared rainfall intensity duration and frequency curves for Medan using the following methodology:

Horner's formula A = (t + d)n where i = rainfall intensity, in mm/hour t = rainfall duration time, in hours A, d and n are regional coefficients and exponents

The regional coefficients and exponents used to characterize the rainfall intensity for 2, 5, 10, 20, 50, and 100 year return periods are shown below, and the rainfall intensity duration curves are shown in Figu re 3.1. Return period, t Rainfall intensity, i (years) (mm/h)

83 2 f(t + 0.28) 0.95

101 (t + 0.28) 0.95

~115 10 (t + 0.30) 0.95

20 134 20 (t + 0.31) 0.95

i= 161 50 (t + 0.34) 0.95

187 (t + 0.36) 0.95

3.5 RUNOFF ANALYSIS

The runoff coefficient represents that proportion of the rainfall that runs off the land surface and into drainage facilities. The value of the coefficient (which can vary from 0 to 1) depends on a number of factors including the permeability of the surface, surface roughness and slope, and the intensity and duration of rainfall. At the beginning of rainfall, water soaks into the ground and then fills small depressions in the surface. As the ground saturates and the surface depressions are filled, the water begins to flow over the surface and the coefficient increases in value.

3-3 FIGURE 3.1

0 / g//

-- Oft 0

I-I Jc'J

cc _ _ _ 0

I-I z

wL 00

Jq/u u ,. ui

J4/W 11VNIVU! A.~.S~a1

PADCODACRA ENINEERNG-SIENC SNC N-NC The runoff coefficient can be estimated, according to Hoad by the following equations:

For impervious areas (i.e., paved streets or pavement)

t ci= t+8

For previous areas (i.e., agricultural land)

0.5t cp = t + 15

where ci, cp = runoff coefficients for impervious and pervious area

t = rainfall duration in minutes.

The runoff coefficient for any area can be considered as a combi nation of impervious and pervious areas. Therefore, the composite runoff coefficient can be estimated by using a weighted average of ci and cp:

c = pci + (1 - p) cp

where c = the composite runoff coefficient

p = fraction of the area that is impervious

The variation of c with t for various percentages of impervious areas is shown on Figure 3.2.

Assumed percentages of impervious area for various land use classi fication are shown below: Percentage of Impervious Area

Commercial 95 Residential 65 Industrial 60 Institutional 35 Open Area 0

The weighted average impervious area under present and projected (year 2000) land use conditions was estimated for each drainage area as shown in Figure 3.3.

3.6 RUNOFF RATES

Runoff was calculated from the formula:

Q = 0.00278 ciA

where Q = runoff from the tributary area, cu m/s c = runoff coefficient i = rainfall intensity, mm/h A = tributary drainage area, ha

9' -- FIGURE 3.2

RUNOFF COEFICIENTS AS A FUNCTION OF RAINFALL DURATION AND PERCENTAGE OF IMPERVIOUS AREA

1.0 PERCENTAGE OF

. IMPERVIOUS AREA 010

Wi 0.51 00/ L PL 0 I I0 I0000I00 z

1 10 100 1000 RAINFALL DURATION minutes

PADCD-DACREA ENG INEER ING-SCI ENCE -SINOTECH D 00

- '.

0.1am6i m~3 S . -S. - .. - S

0.9 % S~

S-S.e

0.0

OR IELSNRI0

'ADCO-DACREA

3est Avuilable Document FIGURE 3

FRACTION OF IMPERVIOUS AREA FOR EXISTING AND FUTURE CONDITIONS

LEGEND

-STUDY AREA BOUNDARY

MAJOR DRAINAGE AREA BOUNDARY S SUB DRAINAGE AREA BOUNDARY FRACTION OF IMPERVIOUS AREA K°RA RI .57 EXISTING 0.KL T FUTURE (2000)

.. TO DELI TUA

-i-p

1 0 I"2 3 3 KILOMETRES

022J .0

Best. Avazikable Document .,.,.,,._ .. Note that the values of c and i depend on the selection of a rainfall duration. Maximum runoff will occur when the rainfall duration is equal to the time required for water falling on the farthest point in the tributary area to travel to the point where the runoff is to be calcula ted. This time is composed of two parts: (1) the inlet time which is the time required for overland flow of water from the farthest point in the tributary area to reach the inlet to the drain and (2) the time of flow in the drain from the inlet to the point where the runoff is being calculated.

An empirical formula from Kirpich was used to calculate the inlet time:

= 0.00032 ti SO.385

where ti = inlet time, h L = length of the tributary basin area, m S = average slope of the tributary area from the farthest point to the inlet

The time of flow in natural channels (main rivers) was determined using the following empirical formula:

td L.6 150,000 H

where td = time of flow in drain L = length of drain from the inlet to the point being considered, m H = difference in elevation between the inlet and the point being considered, m

In all improved drains time of flow in the drain was determined using flow velocity calculated by the Manning formula.

3-9 SECTION 4

PUBLIC HEALTH

4.1 PRESENT CONDITIONS

In any area, the incidence of enteric diseases is a measure of the general level of sanitation. The available health statistics in Medan confirm the problems that are evident even from a cursory examination of the water supply and sanitation systems.

Table 4.1 presents health data for 1978 obtained from the Medan Health Department, the Provincial Health Department, hospitals and other sources. At best, these statistics are incomplete because there is no comprehensive, uniform system in the city for reporting disease incidence statistics. Many disease cases are unreported or are not treated in established health care facilities. As a consequence, the figures shown in Table 4.1 err on the low side.

Comparisons between kecamatans should be made only very cautiously. For example, Kec. Johor reported no cases of diarrhoeal diseases from the Health Centers in 1978. It is highly improbable that there were no cases; it is more likely that cases of diarrhoeal disease that did occur were not reported for one reason or another.

The data shown in Table 4.1, incomplete as they are, strongly support the fact that many people in Medan are using water from unsafe sources. In 1972-73, there was a major outbreak of cholera in North Sumatra where 22,745 cases were reported. This was an increase of about 50 times the rates reported over the previous three years in the Province, Diarrhoeal diseases (for which Health Centers above reported treating foir percent of the population in 1978) are a major contributor to the extremely high Medan infant mortality rate of about 110 per 1000 population.

Typhoid fever is also common in Medan, but it is usually treated in the hospitals and reported only irregularly.

Partial statistics from the Medan Health Centers are available for some other diseases that are related to poor sanitation. These are summarized below:

4-1 \X TABLE 4.1

INCIDENCE OF REPORTED ENTERIC DISEASES IN 1978

Bacillary Dia--hoeal 1978 Hepatitis Cholera Dysentery Diseases Kecamatan Population Cases No./1000 Cases No./1000 Cases No./1000 Cases No./1000

Kota 232,230 884 3.8 296 1.3 4,364 18.8 15,116 65.1 Baru 121,508 307 2.5 55 0.5 948 7.8 4,168 34.3 Barat 132,287 271 2.0 139 1.1 1,249 9.4 13,466 101.8 Timur 178,790 300 1.7 113 0.6 841 4.7 4,216 23.6 Sunggal 94,383 63 0.7 84 0.9 497 5.3 1,427 15.1 Tuntungan 17,475 74 4.2 3 0.2 74 4.2 832 47.6 Johor . 54,660 - - 2 - - - - - Denai 119,416 37 0.3 97 .0.8 213 1.8 350 2.9 Deli 51,456 94 1.8 3 0.1 51 1.0 677 13.2 Labuhan 54,031 - - 192 3.6 1,952 36.1 84 1.6 Belawan 60,000 - - 189 3.2 307 5.1 1,930 32.2

TOTAL 1,116,236 2,030 1.9* 1,173 1.1* 10,496 9.9* 42,268 39.8*

* Excluding Kec. Johor Disease Reported Incidence (cases per 1000 pop.)

Ascaris 6.0 Hookworm 0.5 Scabies 8.1

These incidence rates are extremely misleading, because only the most severely afflicted cases are seen at the Health Centers. Studies reported by the Child Health Department of the Medan General Hospital (RSUPP) indicated that nearly 100 percent of the children in Medan had round worms at some time of the year. One study showed that 87 percent of the children examined had Ascaris (round worm) and 16 percent had hookworms. A special study in Kec. Tuntungan in 1976-77 showed 80 percent of the population were infected with Ascaris and 22 percent were infected with hookworm. A study in Kec. Deli Tua showed that 90 percent of the children had hookworms. Another study showed that 14 percent of the children were infected with Gardia Lamblia.

In 1978 the Medan Health Department reported a total of 2083 cases of malaria from eight of the eleven kecamatans. Two-thirds of the cases were from Kota, Labuhan, and Belawan. Dengue (transmitted by the Aedes aegyptes mosquito which also transmits yellow fever) also occurs in Medan.

4.2 DRAINAGE

The human problems of flooding - property damage, inconvenience, disruption of normal activities - are obvious. Lack of adequate drainage and frequent flooding also represents a major public health problem as indicated previously. Flooding of latrines and septic tanks results in wastes being spread over large areas and pollution of the water supply.

Malaria is prevalent in Medan; in 1978 the Public Health Centers reported 2083 cases. The Anopheles mosquito, the vector of malaria, is commonly found in the area in shallow water in fields and elsewhere. The Public Health Department believes that malaria in Medan is controlled effectively by current programs for spraying houses wherever malaria cases are found. It has also been stated that the malaria cases reported by the Public Health Centers in 1978 were contracted by people travelling outside of Medan.

There are many cases in Medan of dengue and possibly a closely associated disease, hemorrhagic fever, transmitted by the Aedes aegypti mosquito. This mosquito breeds in small quantities of water such as rain water barrels (which are commonly seen under roof drains) cans, containers, old tires and pools. Control of this mosquito involves public education to minimize breeding conditions, solid waste management to try to avoid water-collecting waste containers, and in some cases, special spraying programs.

4-, The Culex mosquito breeds in almost any non-saline water and is reported to be very common in Medan. It is principally a pest which causes annoyance by bitting. Inquiry at the University indicated there have been no local cases of urban filariasis, a serious disease resulting from the bite of the Culex pipiens fatigans mosquito. In some areas like Rangoon and Burma, Culex has been found to breed in heavily polluted water such as water-filled privy vaults and polluted, stagnant drainage ditches. This condition should bc kept in mind, but it is not presently considered a problem in Medan.

Improvement of drainage channels would have some benefit by reducing the breeding places for mosquitoes. For a long time to come it is expected that Medan will have to continue the policy of discharging washwater and other grey water into drainage channels. It must not be assumed that grey water is safe. It does contain various pathogenic microorganisms, although in lower concentrations than black water. Grey water does constitute pollution in drainage ditches and water courses. However, properly separated grey water is nof. excessively offensive if it is discharged into properly graded and maintained channels and ditches. Inspections have repeatedly found the drainage system in Medan to be poorly maintained. Ditches are frequently filled with solid waste and stagnant pools of water are common. These pools constitute a serious public health hazard directly and as a breeding place for disease-bearing insects and a source of con tamination for water supplies.

It is essential that maintenance of the Medan's drainage system be im inproved to provide rapid removal of grey water from developed areas if reasonable standards of public health are to be achieved.

4-4 SECTION 5

DESIGN CRITERIA AND BASIC FOR COST ESTIMATES

5.1 INTRODUCTION

The purpose of this section is to delineate design and cost estimating criteria for the physical facilities required for the drainage system. The design criteria presented herein represent a combination of accepted international and locally developed design concepts. Within the con straints of acceptable levels of performance and good engineering practise, full consideration was given to the need to minimize costs in the capital short environment in which the system must operate.

The cost data presented in this section are based upon the best currently available information obtainable from suppliers and contractors and the records of local agencies. Where appropriate, these data have been modified to reflect the estimated impact of changes in design concepts or construction methods as envisioned for the proposed facilities. All cost figures reflect prices applicable for mid-1979 unless noted otherwise.

Where the alternative evaluation process iir olved costing of a large number of the same type of facility of varying capacities, cost curves were prepared. If the facilities to be compared were few in number, general unit rates for materials and labor were developed for use in estimate preparation. Where appropriate, preliminary screening of alterna tives was carried out on the basis of a comparison of average annual costs.

5.2 DESIGN CRITERIA

5.2.1 General Criteria

The drainage system was designed to be entirely separate from the wastewater collection system to eliminate the possibility of Jaw sewage overflows which frequently occur with combined systems during periods of heavy rainfall. The drainage system will continue to collect grey water from areas which do not have separate sanitary sewers.

5.2.2 Hydraulic Design

The projected stormwater flows which were used to determine the required capacity of each component of the drainage system were deter mined by the rational method as described in Section 3. The required

5-1 capacity of each component was determined from Manning's equation using the following friction factors:

System Component Mannings "n" Deli River 0.030-0.040* Babura River 0.025-0.035* Sikambing River 0.033-0.045* Putih River 0.033-0.048* Kera River 0.020-0.035* Percut River 0.028-0.035* Other natural streams 0.035* Concrete Channels 0.015 Earth Channels 0.025 * n values reflect existing channel conditions such as alignment, vegetative growth, and the presence of solid wastes.

Slopes of natural channels were estimated from 1:50,000 scale topographic maps.

It may be seen from the friction factors presented above the con crete lined channels have a higher hydraulic capacity than earth channels of the same cross section and slope. Lined channels have a second advan tage over earth channels in that lining prevents erosion and this allows concrete channels to be designed for much higher flow velocities than earch channels. Velocities in earch channels are usually limited to a maximum of one metre per second. Concrete channels are often designed for peak velocities of four or five metres per second, which greatly reduces the required cross sectional area. This is often desirable for aesthetic, economic and environmental reasons.

The recommended drainage system must have sufficient capacity to reduce the frequency of flooding that Medan now experiences. When the expected quantities of runoff for design storms of various return fre quencies are computed, drainage system components may be sized to handle those flows without flooding. As the components of the system are in creased in size to reduce the frequency of flooding, the cost of the system increases. It therefore becomes necessary to determine the point beyond which the cost of the system begins to increase more than the benefits in terms of reduced property damage and hardship to the people. The acceptable frequency of flooding in any area depends on the land use and the elements of the drainage system involved. The flood frequencies indicated below were selected as a basis for preliminary design and reflect both the relative damage caused by flooding in different areas, and a realistic appraisal of the level of service which it is economically feasible to provide. The design flood frequencies selected for Medan are shown in comparison with standards which are considered desirable in countries where higher levels of funding are available for flood control.

5-2 Design Flood Desirable Flood Land Use Frequency Frequency (years) (years)- Commercial High Value 5 10-50 Residential 2 5-15 Agricultural 1 2-10 Open 1 1-5

This comparison indicates that continued improvements to the recommended system are desirable and should be made whenever additional funds become available.

5.2.3 Rivers

Consideration was given to the possibility of straightening or lining river channels to increase their hydraulic capacity and reduce the potential for flooding. This can be very expensive and there are environmental issues involved which must be carefully considered. There are, however, many situations where the benefits of channelization justify these costs. Estimates of the improvement that channelization could provide were made using Manning's equation. Friction factors were se lected from those indicated in 5.2.2, according to the type of modification being considered.

5.2.4 Major Channels

Major channels include those which are constructed to collect flows from local drains and streams which will be extensively enlarged, straightened and, in some places, lined with concrete. Typical cross sections proposed for lined and unlined channels are shown in Figure 5.1

5.2.5 Local Drains

The alternative types of channels which are suitable for roadside drair age collection are shown in Figure 5.2. Covered rectangular box culverts are proposed only for densely developed urban areas where open drains are not practical.

5.3 BASES FOR COST ESTIMATION

5.3.1 General Bases for Pricing

Current prices of local materials and labor in Medan are summarized in Table 5.1. The unit prices of earthwork and masonry include the costs of labor, materials, equipment, a ten percent contractors overhead and ten percent allowance for contractors profit. No provision is included for supervision and taxes.

5-3 FIGURE 5.1

TYPICAL LINED CHANNELS

O.60m B+2H 0.60m H B'

-CONCRETE BLOCKS

GRAVEL BED

0.50m 0.20 m

b > 0.3 m _

hb =- 0 . • 45 . 2 h ib 2 h CONCRETE

LINED

, B+ 2H

H H / I /

b+4

b = 0.1 B __2h lb 2h b > 0.3m Is h x 0.25b UNLINED

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH FIGURE 5.2

TYPICAL LOCAL DRAINS

H H 0.90 m l*0.20m

OL GL /0.12m

H"0.50m

BRCK 0.15 mA15

0.10Om O_____"__CONCRETE

•0.15m

LINED

-H.---aO.om

.10

UNLINED

PAD CO-DACREA ENGINEERING-SCIENCE - SINOTECH TABLE 5.1

GENERAL MATERIALS AND LABOR COSTS

Des -ription Unit Unit Cost (Rp.)

Labor Unskilled labor day 700 Skilled labor Mason day 1,200 Carpenter day 1,400 Assistant to skilled labor day 800 Foreman day 1,250

Material (delivered to site) Sand for filling Cu m 1,400 Sand for mortar cu m 1,700 Sand for concrete cu m 2,000 Gravel for concrete cu m 2,900 Broken stone cu M 3,400 Sirtu (sandy stone) cu m 2,400 Crushed stone cu m 3,900 Brick 100 pcs 1,850 Portland cement (Cibinong) 40 kg 2,100 Lime 100 kg 3,500 Asphalt 100 kg 9,000 Reinforcement steel kg 300

Earthworks Excavation by hand 0-1 metre cu m 500 0-2 metres cu m 600 Soil transport by pikulan over maximum distance of 50-100 m cu m 200 Back filling cu m 250 Sand filling cu m 1,500 Loading and unloading of truck using man-power cu m 250 Trench excavation up to 'depth of 1.5 m cu m 550 Filling including compaction (each layer 20 cm) cu m 1,250

Masonry Stone masonry cu m 19,500 Plastering sq m 750 Concrete mixed in place 1:3:5 cu M. 18,000 Concrete mixed in place 1:2:3 cu m 23,000 Reinf. steel including binding and placing 100 kg 45,000 Timber formwork for concrete cu m 57,000

5-6 TABLE 5.1--Continued

Description Unit Unit Cost (Rp.)

Housing material Paint Wall paint 3.5 litres 6,900 Wood paint 1 litres 2,750 Roof Cement roof tile pCs 100 Corrugated asbestos cement 14 x 4 mm x 5 feet sheet 2,200 Asbestos cement roof 4 mm x 1 m x 2 m sheet 2,360 Floor P.C. Tile 20 x 20 pcs 45 P.C. Tile 30 x 30 pcs 160 Glass (transparent) t = 3 mm sq m 3,500 t = 5 mm sq m 5,750

Wood - depending on quality (1 ton - 1.35 cu m) ton 40,000 to 115,000

5.3.1.1 Price Contingencies

No allowance has been made in this study for price escalation arising from inflationary causes. The prices used are current market prices prevalent around mid-1979.

5.3.1.2 Engineering Services

The cost of engineering services during the design and construction phase is estimated at ten percent of the construction cost of the facili ties and has been accordingly included in the estimates.

5.3.1.3 Physical Contingencies

A physical contingency allowance of 15 percent has been added to the estimated costs of all facilities to provide for any unexpected items of work that may be found necessary during construction and also to pro vide for any inadvertant omissions or other inaccuracies in the cost estimates.

5-7 5.3.2 Drainage System

5.3.2.1 River Channel Improvement

River channel improvements will be carried out in selected reaches of the major rivers in the study area which act as "bottlenecks" in drainage system. the These improvements will involve dredging and channel widening. The cost of this dredging was estimated to vary from Rp.l,000 to Rp.l,200 per cubic metre of earth depending on the location of the proposed work.

5.3.2.2 Major Drains

The estimated costs of constructing major lined and unlined drains of various sizes are shown in Figures 5. 3 and 5.4 , respectively. The estimated costs of lining existing major drains of various sizes are shown in Figure 5. 5 . The estimated costs of installing closed box culverts of various sizes are shown in Figure 5. 6.

5.3.2.3 Local Drains

The cost of installing new lined roadside drains was estimated to be Rp.13.0 x 106 per kilometre. The cost of repairing existing lined roadside drains was estimated to be Rp.ll.5 x 106 per kilometre. Both of these estimates are based on the use of lined drains as shown in Figure 5.2. The estimated cost of unlined local drains shown in Figure 5.2 is Rp.5.0 x 105 per kilometre.

5.3.2.4 Maintenance

The estimated annual system maintenance costs were based on the estimated rate of accumulation of silt and debris in the channels and on the estimated unit cost of removing and disposing of this debris. It was estimated that 0.5 m of debris per year must be removed from all drains and that the unit costs associated with cleaning drains are as follows:

Cost of removing debris from drain - Rp. 400 per cubic metre Cost of transporting debris to landfill - Rp. 700 per cubic metre Cost of disposing of debris in landfill - Rp. 350 per cubic metre

Total Cost Rp.l,450/cu m

5,-8 FIGURE 5.3

CONSTRUCTION COSTS FOR LINED OPEN CHANNELS

IOop

800

60C

400(

H:5

H 4

o EH 2

0 60.-

0I040

80 20-

IO ___

1 2 3 4 5 6 7 8 9 10 WIDTH OF OPEN CHANNEL , inm

PANCO-ACREA ENGINEERING-SCIENCE SINOTECH FIGURE 5.4

EXCAVATION COSTS FOR UNLINED OPEN CHANNELS

200-

H 5

I00 -

H :2

H=I

0';

08. z o 6

H DEPTH OF OPEN CHANNEL IN METRES

2 NOTE :COST INCLUDES LABOR AND EQUIPMENT

I 2 3 4 F. 6 7 8 10 WIDTH OF OPEN CHANNEL, in m

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH 61 FIGURE 5.5

COST OF LINING EXISTING UNLINED OPEN CHANNELS

300

200 H 5

a H: 4 0L H: 3

I~00 __"_ __ H:

H 2oI0 0 .. C60

H DEPTH OF CHANNEL IN METRES z o 20 NOTE - COST INCLUDES

1 2 3 4 5 6 7 8 9 10 WIDTH OF CHANNEL.,in m

S,3

PADCO-DACREA ENGINEERING-SCIENCE -SINOTECH FIGURE 5.6

COST OF BOX CULVERTS

2,000

TRIPLE CULVERT .0

1,000 6r

800 8O0 0

"00 DOUBLE CULVERT .

0 00 Vo0

:00

IL o 60____

0 40

KCHANNEL HEIGHT KCHANNEL WIDTH

20 - ______

I0 1.0 1.5 2.0 2.5 3.0 3.5 4.0

PADCO-DACREA = Pr , oUf.,MDIi,unrrnu ( SECTION 6

ALTERNATIVE DRAINAGE MANAGEMENT SYSTEMS

6.1 INTRODUCTION

In Sectioi. 2 the characteristics of the existing drainage system including flooding problems have been described. In Section 3 the present and projected capacity requirements of the drainage system have been estimated.

In this section alternative levels of service which may be provided for flood control are reviewed and alternative methods for achieving the various service levels are screened for possible application in Medan.

Alternative staged programs for implementing drainage improvements are also developed and evaluated in relationship with local capabilities and ultimate system needs.

6.2 ALTERNATIVE SERVICE AREAS AND SERVICE LEVELS

The following three service areas have been identified for purposes of evaluating alternative drainage systems as shown in Figure 6.1:

1. Present high density, high value urban area (priority 1).

2. Present medium density high value urban area (priority 2).

3. Present low density areas which will become more fully development by year 2000 (priority 3).

These service areas provide a basis for the spatial development of staged alternatives.

The quality of service provided by a drainage system is most fre quently described by the level of flood protection that it affords. Other features of the drainage system can also directly and indirectly contribute to the quality of service. These include the degree of iso lation between drains and their contents and the environment. Open channels are less isolated than underground closed conduits and therefore present a higher degree of potential health hazard and danger to children playing near them. Nuisance and inconvenience frequently associated with open channels in business areas can make access to shops and other

6-1 places of business inconvenient and unpleasant. Stream bank and roadside erosion also can result in property damage and ircreased maintenance cost.

Service levels for flood control are typieallv stated in terms of the capacity of a drain to carry flows which could be expected to be equalled or exceeded once, on average, over a specified time interval, usually expressed in years as the recurrence interval.

The level of protection frequently selected for various elements of drainage systems in urban areas varies from recurrence intervals of two years in residential areas to in excess of 100 years in urban areas where the potential for property drainage and loss of life is high. Specific values used for system evaluation are determined by economic analysis and by engineering judgement.

The level of service stated in terms of the physical quality of the drainage system can be classified as follows:

- Open channels " earth improved " lined

- Underground closed conduits with local open channels with roadway gutters and inlets and building connections.

In Medan where the surface drainage system carries wastewater flow and receives substantial quantities of solid wastes, open channels present a potential threat to the health of citizens and detract from the aes thetic quality of the city because of udors and unsightlines.

6.3 ALTERNATIVE FORMS OF SLOOD CONTROL

6.3.1 Reduction of Flood Runoff

The reduction of flood runoff can be accomplished by:

1. The control of land use and building construction

2. Land treatment methods

3. In channel and off channel storage and flood routing.

The application of these methods of flood control is becoming more prevalent in urban drainage systems because of the savings that can be realized in storm sewer construction and in some cases environmental benefits that can be achieved by the preservation of natural water cources.

In Medan the control of land use and building construction cannot yet be exercised to the extent necessary to accomplish significant reduc tions of flood runoff. In areas which are presently undeveloped the appli cation of off channel storage can be considered as well as flood routing alternatives in specific situations.

6-2 J.. 1-J,

BELAWAN RIVER

PADCO-DACREA

Best Avaiobwe DocucsA FIGURE 6.

DRAINAGE SERVICE AREAS

...... LEGEND

' PRESENT HIGH DENSITY, HIGH ,I'VALUE URBAN AREA (FIRST J. -PRIORITY AREA)

,, PRESENT MEDIUM DENSITY, HIGH VALUE URBAN AREA (SECOND PRIORITY AREA)

YEAR 2000 URBAN "" ,DEVELOPMENT (THIRD PRIORITY AREA)

DEE

I- .' . ..

0 DELI TU

" ;I KILOMETRES

* ,*, ...

4W4 RIV

.- ,.-/

ENGINEERING-SCIENCE - SINOTEC

'AiwlaleDocumanl Controlling flood flows resulting from intense rainfall is a prime concern in flood control management. One way of controlling such flow is by impounding excess flow and releasing it once the peak flow has passed. The siting of impoundment reservoirs may be considered to reduce down stream flood flow on the Deli River. Appropriate sites do not appear to be abundant to the south of Medan and this fact affects the feasibility of such alternatives.

6.3.2 Improved Inlet

In Medan many of the inlets to local drains and from local drains to major drains are blocked, partially or completely restricting the flow of water from residential and commercial areas and creating upstream ponding.

Clearing existing inlets from local drains to major drains will diminish the amount of ponding and can dramatically improve flooding conditions in some areas.

Inlet conditions can also be improved by providing enclosed buil ding connections connecting building drainage systems and yard drains to the local surface drains. Such inlets should be properly constructed to prevent debris and sediment from entering the drainage system.

6.3.3 Increased Channel Capacity

Increased channel capacity will undoubtedly continue to be the flood control measure having most widespread application in Medan. Such measures include channel clearing, cleaning and dredging, channel straightening, enlargement and lining.

Many of the drainage channels in the study area are severely con stricted by vegetative growth and by solid wastes. In addition, erosion caused by rainfall in southern rural areas has created sedimentation problems in the lower reaches of the major rivers.

Clearing, cleaning and dredging will significantly increase channel capacity. Field inspections carried out as part of this study suggest that an increase in channel capcity of as much as 50 to 100 percent could reasonably be expected by channel clearing, cleaning and dredging alone. Channel straightening and enlarging in the densely developed urban areas of the city is made difficult because of residential development near the streams which in some instances has been observed to encroach upon the flood waterway.

In the lower reaches of the major rivers extensive widening of the waterway will create unstable stream bed conditions that will require extensive maintenance to retain capacity.

In the densely developed areas of the city diking existing channels would necessitate pumping to ensure drainage of low lying areas when the major river channels are carrying flood flows. Deepening channels can be considered in some areas. In the lower reaches of the major rivers outlet *iscontrolled by sea level and sediments deposited at the mouths of the rivers. 6-5 (' Channel lining to reduce flow resistance must therefore be con sidered for drains within the densely developed urban area.

6.3.4 Avoidance and Mitigation of Flood Damage

Flood protection measures in addition to those provided by the control of runoff and increased drainage system capacity can be accom plished by both the public and private sectors to avoid flood damage, such as:

a Land use control, regulating development in areas subject to flooding.

* Site development, such as filling areas on which development is to occur.

0 Constructing private diking systems.

In areas where measures are not taken to avoid flooding damage precautions can be taken to ensure that damage is minimized and other effects of flooding are mitigated. These include:

" A stream flow monitoring and warning system.

* Assistance with evacuation

" Emergency health care, food and accommodation for flood victims.

" Assistance with clean up operations.

6.3.5 Control of Other Features

In areas where access and aesthetics play an important role in the operation of the drainage system detrimental effects can be avoided by enclosing drains beneath the street surface and by providing curbs and gutters, inlets and catch basins. When such systensare installed care ful attention must be given to final road elevations, grades and street cross sections to ensure satisfactory outlet for drainage from adjacent properties including requirements for the installation of building con nections.

Public health and aesthetic problems will also be reduced with the long term provision of sanitary sewers. Building plumbing systems should provide for the separation of surface water and wastewater flows during initial construction to avoid costly separation work at some future time.

6.4 EVALUATION OF ALTERNATIVE DRAINAGE SYSTEM IMPROVEMENTS

In the following subsection the application of the foregoing service levels and control elements to the various physical components of drainage system, service areas and service groups are examined and those alternatives having particular application in Medan are sefected.

6-6 6.4.1 Major River Channels

6.4.1.1 Lower Deli River

The existing capacity of the lower Deli River below its confluence with the Babura and the estimated capacity requirements are illustrated in Figure 6.2.

Although this analysis is approximate only, because of the limited streamflow data available, it can generally be concluded that over bank flooding of the Deli River can be expected to occur frequently.

The tributary area of the lower Deli River is bisected by two potential obstructions, the railway and roadway embankments immediately to the east of the river. Although flooding is certainly caused by over bank flow,some local ponding may be atributed to restrictions to flow through these embankments.

The area subject to flooding within the tributary area of the lower Deli is agricultural with the exception of a strip Of land between the river and railway in which there is significant industrial development and a small relatively densely populated urban area above the confluence of the Sikambing River.

Current preliminary plans for enlarging the channel of the lower Deli have been based on a flow capacity of 800 cu.m/s, a relatively large flood flow.

Impoundments at locations upstream of Medan can be constructed to reduce the magnitude of flood flows. Multiple use of such impoundments for irrigation and water supply could be considered. The degree of flood protection that can be provided and the cost is a matter for detailed specific investigation. Optimum reservoir systems would undoubtedly in volve a combination of channel improvements and reservoir storage. Re duction3 in flood flows of possibly 25 to 50 percent could be expected at a cost comparable to the program of channel improvements which provide a moderate level of flood protection. This option should be studied further at the time reservoirs may be considered for water supply or irrigation purposes and when further major channel improvements are considered in the lower Deli.

Channel clearing, cleaning and dredging in the lower Deli is esti mated to cost Rp. 0.3 x 109.

The estimated cost of an enlarged unlined channel for the lower Deli River capable of providing a moderate level of flood protection (roughly a 5 year recurrence interval) is about Rp. 3 x l0J to Rp. 4 x 109. The benefits that would be derived from expenditures of this magnitude would have to be carefully evaluated before implementing such schemes.

6-7 ...... require careful evaluation %- u c nnei n rne lower Deli would also In relation to sedimentation and vegetative growth to ensure that channel capacity is maintained once initial con struction is complete, Major expenditures in the lower Deli River should dered until not be consi more reliable flood flow data become available. time In the mean significant benefits could be derived by cleaning,clearing dredging the existing and channel. Diking in selected areas could also considered to provide be an additional measure of flood control, however, flooding could continue to occur relatively frequently especially in lower areas.

Controls on land use and site development within the area subjeLt to flooding should also be instituted to avoid flooding damage. This area would also benefit greatly from a program to mitigate the effects of flooding that does occur as previously described.

6.4.1.2 Upper Deli River Figure 6.2 illustrates that the existing channel capacity Deli River upstream of its of the confluence with the Babura is capable of pro viding a high degree of protection from overbaLU. flooding (possibly in excess of a 20 year recurrence interval). The extensive flooding that occurs in part of east Medan is beyond the natural boundary of the upper Deli River catchment area. The tribu tary area has been extended easterly to Jalan Sutomo where a drain has been constructed diverting flow from the Kera River basin to the Deli River at a junction point downstream of the Babura. The southerly extre mity of this drain serves a relatively small part of the Kota Matsum area. Flooding is not prevalent in the area served by the Jalan drain or by the Sutomo upper Deli River. Such local drainage problems exist appear to that do be attributable to development that has occurred the flood within waterway and flood plain and to local ponding. It is recommended that only relatively minor channel improvements be carried out in the upper Deli River channel to ensure that the potential of the full existing channel is available for flood protection.

6.4.1.3 Babura River A& illustrated in Figure 6.3, within the present high and medium density urban area, the existing channel, like that of the Deli River, has adequate capacity to provide a high level of flood protection. Flooding problems within its tributary area appear to be attributable to defficiencies in local drains. Like the upper Deli River,relatively minor channel improvements are required to ensure that the full potential of the existing channel is realized. In the southerly portion of the study area relatively broad and well defined flood plains exist which are extensively used for agricultural purposes. Urban development in these flood plains should be controlled by appropriute zoning regulations. Some relatively minor channel improvements may be required in the future when development in the general area is considered.

6-8 (A\ 600.

CCUtLATED RUNOFF FROM PEAK STOM RUNOFF 700- IWmh1Y ORANME AREA

. . 600- It ...... Lo5 o -5000 ' i. 0...

2.YEARS z040 - 0-"1

Ii. 300 =oo.owq1...I o ® . ..

0 200-

EXISTING RIVER CAPACITY WITH FREE BOARD 100 -

0 ,

10 12 14 IS 0 2 4 a DI!

PADCO-DACREA FI GURE

r--

20 YEARS

10 I IYEARS.

3 YEARS "c I 4) I I

I0 YEARS rTWEE~C

DELI AND MILA RIVER CON4FLUENCE BTWEN IDELI AND SIKAMING RIVERS

is 5 20 22 24 26 23 34 DISTANCEKm

Best AvailPl. ROJECTED STORM RUNOFF I9 mDEl FOR DELI RIVER BASIN

ENGINEERING-SCIENCE - SINETE FIGURE 6.3

I I_. ®

u j'q~I~usi~ 00

. w IIL 4c c oi I

M IE w I

1 0I.i -I -" , I Wh o -, U- I I - 0 1..1 z I

wI - 0 _____1 ocI r

00 9/w no~ tY4NnmJ N

PADC07DACREA ENGINEERING-SCIENCE -SINOTECH./J 6.4.1.4 Belawan River

Only a relatively small portion of the watershed of the Belawan lies within the study area. Flooding problems within the study area attributable to the overflow of river banks have not been reported. Development within the study area is not likely to contribute signifi cantly to an increase in flooding potential downstream of Medan.

The channels and flood plains of this river through the study area are well defined. The control of flood plain development and adequate routine channel maintenance are considered to be adequate flood control measures in these areas.

6.4.1.5 Percut River

The Percut River, like the Belawan River, has only a small portion of its tributary area within the study area and severe flooding damage has not been reported although most of the reaches within the study area have limited channel capacity as illustrated in Figure 6.4. The flood plains in these areas are well defined and development within areas sub ject to inundation should be controlled by regulation. The Percut River receives flood flow diverted from the Kera basin and some future channel improvements in the form of channel cleaning, clearing and dredging are proposed.

6.4.2 Major Drains

6.4.2.1 Kera River

The capacity of the main channel of the Kera River in relation to flood projected flows is shown in Figure 6.5. Regular flooding occurs extensively throughout the Kera River watershed within the study area. Flooding is attributable in part to overbank flow And to local ponding caused by deficiences in local drains. A diversion to the nearby Percut River has been constructed to provide relief to the downstream reaches of the Kera and major channel improvements have been carried out for improved flood control. Present high density high value and medium density high value areas are affected by flooding particularly to the west of the Kera River channel. In the Kera basin there is little option to improve flood control by means other than increasing channel capacity.

Clearing, cleaning and dredging of the existing channel will signi ficantly-increase the level of flood protection, however,a preliminary analysis indicates that frequent flooding could still be experienced. The Topography of the area and alignment of the existing channel is such that the construction of a relief channel or channels could be considered as an alternative to increasing the size of the existing channel. The high density high value land use comprising much of the area subject to over bank flooding suggests that at least a moderate level of flood protection should be considered for this area.

Figure 6.6 illustrates channel costs for main drains of various types of construction and for various degrees of flood protection.

6-12 FIGURE 6.4

2 _® '1-.' ,t

L, - 00I , i,®

w wnI .I=IN z r IL 0

a. P

01 H 0

w/ no I!.o~a PA.C-ACEAEGIERIG-CENE-IINTC!! FIGURE 6.5

C',Y

'C V5 wm a:

z w

0L0 I-Q w0

co a0

0 0

0 0w

0 0 0 0 mg N

PADCO-DACR EA ENGINEERING-SCIENCE - SINOTECH FIGURE 6.6

TYPICAL COMPARATIVE COSTS OF MAIN DRAINS

2000-

CLOSiED CONDUIT -mm - E - - - m -m - - -m~m - - -wm - -

HIGH LAND COST URBAN AREA (60,000 sq m ) CHAN"_L.L___- Siooo_ UNLINED OPEN ""-" - LINED OPEN CHANNEL

0 MODERATE LAND COSTS LAND COSTS NOT INCLUDED URBAN AREA 0. (rODOsq m) O LINED OPEN CHANNEL

UNLINED OPEN CHANNEL

0 I1 2 5 10 20

FLOOD FLOW RETURN PERIOD, years

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH) It can be seen from the figure that the construction cost of pro viding increasing levels of flood protection for channels of similar type is relatively small in comparison with the cost of providing improved channel types.

When land for drain rights-of-way must be acquired land costs are an important factor in the selection of channel type. However, figure 6.6 illustrates that enclosing main drains cannot be justified on the basis of construction and land costs alone.

The potential for damage caused by the erosion of channel banks and over bank flooding is higher than for local drains by virtue of the greater quantities of flow conveyed. This requirement for a greater overall reliability of service can be satisfied by providing a higher degree of channel capacity and by providing features which will minimize maintenance needs.

It is recommended therefore that all main channels be constructed to provide relief from flood flows with a 5-year recurrence interval and that the channels be lined in all high and medium density areas.

6.4.2.2 Sikambing River

Figure 6.7 illustrates that the capacity of the present Sikambing channel can be expected to be exceeded frequently. Overbank flooding problems have been reported in the vicinity of Jalan Binjei. The absence of problems in other areas is due in part,no doubt, to the lower density of development in areas which may be inundated.

At the present time the provision a high level of flood protection need not be considered. In the short term, channel clearing, cleaning and dredging will substantially increase channel capacity and channel improvements to provide moderate levels of flood protection can be con sidered when future conditions indicate a requirement.

The area subject to flooding adjacent to the Sikambing appears well defined and land use controls should be instituted to control development in areas subject to inundation.

6.4.2.3 Putih River

The watershed of the Putih lies almost entirely within the existing high density high value urban area. Some channel improvements have been carried out, but extensive blockage by solid waste has occurred in the improved reaches. Although the analysis of channel adequacy illustrated in Figure 6.8 indicates that frequent overbank flooding might be expected extensive flooding problems have not been reported. Flooding due to local ponding occurs frequently and is considered to be attributable to deficien cies of local drains.

Channel clearing and cleaning and dredging in improved sections of the streamshould be undertaken to ensure that the maximum potential of the improved drain is realized. Future operation of the drain should be moni tored before implementing additional improvements.

6-16 FIGURE 6.7

I_ ®

H r

0 w z 0 z

00D

0)0

0 0W I" U- O-w ILI

0 a:;:: a: U- I

U- e 0PW

0 w 4c ox 0

0: 0 0. w- 3144 -

ENIERN-CEC - IOT PACiDARE ;, FIGURE 6.8

C')

wLu o:! 0

a. U.

W Ui LL > I- o0. N i 0J I I WD o- o EIN LI

0 0 o/ oeAOn

PADO-DCRE ENINERIN-SCENC -SINOTECH,~ 6.4.2.4 Badra River

Within the study area extensive flooding occurs in the upper reaches of the Badra watershed which appears to result from ponding caused by restrictions to flow at the Jalan Binjai and railway embank ments. A similar condition exists to the north which affects the Medan I housing development. Flooding in both of these areas is atributable to deficiencies in local drains which are discussed in the following subsection.

6.4.3 Local Drainage Works

6.4.3.1 Local Drains

Local drains may be classified as street drains, which provide for the drainage of individual streets and adjacent properties; and submain drains which receive flow from a relatively small number of street drains and carry the flow to the main drains and major rivers discussed previously.

The improvement of local submains has been reviewed throughout the study area as illustrated in Figure 6.9.

Alternatives for local drainage can be considered in terms of the degree of flood prote:tion afforded and the degree of isolation from the urban environment. Open improved earth channels, open concrete lined channels, and enclosed buried conduits have been applied in Medan in the past. Typical characteristics and unit costs of conduits having similar carrying capacities are illustrated in Figure 6.10. Drain costs increase dramatically with improved channel type. The relative increase in unit costs of providing increased flood protection is less dramatic.

In very high density high value areas, traffic conditions, land values, and physical constraints of existing development may require the consideration of lining and enclosing drains. In other areas channel lining should primarily be consideredwhen justified on the basis of re duced maintenance costs, access and land values.

Careful attention must also be paid to the appurtenances of local drainage works. In the case of open drains access culverts and culverts at street intersections must be adequately sized. Where closed conduits are provided sufficient inlets must be installed and measures taken to avoid erosion of street and roadside surfaces by the provision of curbs and gutters. Catch basins should also be provided at inlets to control the entry of sediment into the underground conduits which may obstruct flow.

Connections from adjacent properties may also be necessary because of drainage conditions on properties adjacent to the street. These may take the form of building connections, connecting stormwater drains in buildings directly to the street drains, and yard drains connecting low lying areas to the underground street drains with elevations selected to provide for gravity outlet.

6-19 When storm drains are constructed under city streets attention must be given to the relative elevations of other utilities to avoid interfer ence. New local street drains are typically constructed in conjunction with new roads or with major road and street redevelopment projects. It is assumed that this practice will continue with funds for such drains provided in road development budgets. However, such drains should be designed and constructed to conform with the requirements of the drainage program. Drainage capital cost estimates do not include local street drains on new or redeveloped streets.

6.4.4 Summary

In the foregoing sections considerations relating to the alterna tive service objectives, service areas, and drainage areas have been discussed.

Service objectives selected for application in Medan for purposes of Master Plan Development are summarized in Table 6.1.

6-20 25 0

324

PADCO-DACREA FIGURE 6

'. -PROPOSED LOCAL SUBMAIN DRAINS

.. -L EG E N D

-STUDY AREA BOUNDARY

MAJOR DRAINAGE BOUNDARY I5 i2 PROPOSED SUBUAIN 13 ' " ' (WITH REFERENCE NUMBER ) . . " RIVERS AND MAIN DRAINS

1' 0 1U Ea' R SAIN

Rl.

5"11 FIGURE 6.10

TYPICAL: COMPARATIVE CAPITAL COSTS - LOCAL DRAINS

250

p 200- -1)

- - -

-. 150 LINED oPE.

0 HIGH LAND COST (60,000 Rp/sq m)

0 VaBURIED CONDUIT 100- -IZBURIED CNDI

I-LAND COST \ -MODERATE LAND COST (10, 00Rp/ sq m 0 EXLUDED 7 URBAN AREA 50 0 50

UNLINED OPEN CHANNEL C-) LINED OPEN CHANNEL 0 ~UNLINED OP

0 I 2

FLOOD FLOW RETURN PERIOD, years

SINOTECW* - PADCO-DACREA ENGINEERING-SCIENCE TABLE 6.1

DRAINAGE MANAGEMENT SYSTEM - SERVICE OBJECTIVES

Description

Service Facilities Flood Flow Return Level Interval - years Application

1. a Enclosed channel with 5 Local street drains high density,high value full street improve- commercial districts submains in commercial ments districts

b Enclosed channel with 2 Local street drains in high density lower full street value commercial districts ON I improvements 2. a Enclosed channel 5 Submains in medium and low density high value commercial districts

b Enclosed channel 2 Submainsin medium and low density lower value commercial districts

3. a Lined open channels 5 Main drains and other submains in high density and medium density areas

b Lined open channels 2 Submains in low density areas Local street and lorong drains in high and medium density areas TABLE 6.1--Continued

Description

Service Facilities Flood Flow Return Appli-ation Level interval - years

4. a Improved earth open 5* Major river waterways channels

b Improved earth open 2 Local street and lorong drains in low density areas. channels

* The objective for the lower Deli is tentative and is subject to review and revision based on monitoring data. In SECTION 7

RECOMMENDED DRAINAGE MANAGEMENT SYSTEM

In the previous section alternatie systems for the improvement of drainage and the control of flooding were evaluated and a recommended staged program was selected for further development.

Further details o the recommended system are presented in 'is section including requirements for organization,administration,operations and maintenance,as well as system monitoring and performance evaluation. use An implementation schedule and cost estimates are provided for in subsequent feasibility studies.

7.1 DESCRIPTION OF RECOMMENDED SYSTEM

7,1.1 General

The major elements of the recommended drainage management system are as follows:

1. Kera Basin

Staged implementation of major improvements in the Kera Basin which are to be initiated immediately and are to be completed by 1990 with the objective of providing a moderate level of flood protection. Figure 6.9 shows the tributary area boundary, main drains and submain drains in the Kera Basin.

2. Urban Area

Throughout the program period to year 2000, carry out a continuous program of channel clearing, cleaning, and dred ging in the urban area and other areas subject to flooding with the objective of ensuring that the flood control poten tial of existing channels is realized. Figure 6.1 shows the boundary of the urban area.

3. Monitoring

Monitor drainage system operation after initial channel cleaning and throughout the program period to provide basic

7-1 <2 design and performance eva luation data and to establish

priorities for future channel improvements..

4. Downstream Channel Clearing, Cleaning, and Dredging

After initial monitoring data has been evaluated,initiate long term program for drainage in downstream reaches of major rivers and drains, primarily the lower Deli River and Kera River.

5. Channel Improvements

Immediately initiate and continuously execute a channel im provement and new channel construction program. The program to be coordinated with:

" the flood monitoring program

* road improvement and construction program

" implementation of the sanitary sewerage program and other utility programs.

6. A program for providing flood warning and emergency assistance and relief for flood victims. 7. Control of urban development (land use, site development and building construction).

8. Training and technical assistance.

7.1.2 Description of Recommended System

The physical works proposed for each stage of the program in each of the service and drainage areas is summarized in Table 7.1.

7.2 OPERATIONS AND MAINTENANCE

7 .2.1 System Operation

Operation and maintenance work will consist primarily of drain and catch basin clearing and cleaning. These operations can be most economically carried out by current labour intensive methods.

7 .2.2 Monitoring

7 .2.2.1 Flow Recording and Inundation Records

Further basic flood flow data is required to complete the evalu ation of flooding problems, especially for the lower Deli River.

7-2 TABLE 7.1

APPLICATION OF SERVICE OBJECTIVES a

Staged Alternative Stat, I Stage II Stage III Service Area b Service Area Service Area Drainage Basin 1 2 3 1 2 3 1 2 3

Lower Deli c Main channel d CCD CCD - - CCD 4a 4a 4a Local drains Submains CCD CCD CCD 3a 3a CCD 3a 3a 3b Street e Res High Value CCD CCD - CCD CCD CCD 3b 3b 3b Res Low Value CCD CC) - CCD CCD CCD 3b 3b 4b Com High Value CCD CCI - la 2a CCD la 2a 2a Com Low Value CCD CCD - lb 2b CCD lb 2b 2b Upper Deli Main channel CCD CCD - CCD CCD CCD CCD CCD CCD Local drains Submains d 3a 3a CCD 3a 3a 3b 3a 3a 3b Street Res High Value CCD CCD - CCD CCD CCD 3b 3b 4b Res Low Value CCD CCD - CCD CCD CCD 3b 3b 4b Corn High Value CCD CCD - la 2a CCD la 2a 2a Com Low Value CCD CCD - lb 2b CCD lb 2b 2b Babura h CCD Main channel CCD CCD - CCD CCD CCD CCD CCD Local drains Submains g 3a 3a CCD 3a 3a 3b 3a 3a 3b Street Res HighValue CCD CCD - CCD CCD CCD 3b 3b 4b Res Low Value CCD CCD - CCD CCD CCD 3b 3b 4b Corn High Value CCD CCD - la 2a CCD la 2a 2a Corn Low Value CCD CCD - lb 2b CCD lb 2b 2b

Notes: a. See Table 6.1 for definition of service objectives. b. Refer to Figure 6.1 for service area boundaries. c. CCD means clear clean and dredge existing channels. d. The improvement objective suggested for the lower Deli is tentative and is subject to review and revision based upon monitoring data. e. Street drains includes submains on streets in commercial areas. f. Clearing, cleaning and dredging of the upper Deli channel will ensure that a high level of flood protection is maintained. g. Submain improvements to be selectively initiated in Stage I to correct specific problem situations. h. In the upper reaches of the Babura provision is made for some channel improvements.

7-3 TABLE 7 .1--Continued

Staged Alternative Stage I Stage II Stage III Service Area Service Area Service Area Drainage Basin 1 2 3 1 2 3 1 2 3 Percut Main channel N/A N/A - N/A N/A CCD N/A N/A 4a Local drains Submains N/A N/A - N/A N/A CCD N/A N/A 3b Street Res High Value N/A N/A - N/A N/A CCD N/A N/A 4b Res Low Value N/A N/A - N/A N/A CCD N/A N/A 4b Com High Value N/A N/A - N/A N/A CCD N/A N/A 2a Com Low Value N/A N/A - N/A N/A CCD N/A N/A 2b Belawan Main channel N/A N/A - N/A N/A CCD N/A N/A CCDi Local drains Submains N/A N/A - N/A N/A CCD N/A N/A 3b Street Res HighValue N/A N/A - N/A N/A CCD N/A N/A 4b Res Low Value N/A N/A - N/A N/A CCD N/A N/A 4b Com HighValue N/A N/A - N/A N/A CCD N/A N/A 2a Com Low Value N/A N/A - N/A N/A CCD N/A N/A 2b Kera J Main channel 3a 3a 3b 3a 3a 3b - - - Local drains Submains 3a 3a 3b 3a 3a 3b - - - Street Res HighValue 3b 3b 4b 3b 3b 4b - - - Res Low Value 3b 3b 4b 3b 3b 4b - - - Com HighValue la 2a 2a la 2a 2a - - - Com Low Value lb 2b 2b lb 2b 2b - - - Sikambing Main channel N/A CCD - N/A 4a CCD N/A 4a 4a Local drains Submains N/A CCD - N/A 3a CCD N/A 3a 3b Street Res High Value N/A CCD - N/A CCD CCD N/A 3b 4b Res Low Value N/A CCD - N/A CCD CCD N/A 3b 4b Com High Value N/A CCD - N/A CCD CCD N/A 2a 2a Com Low Value N/A CCD - N/A CCD CCD N/A 2b 2b i. Channel clearing, cleaning and dredging will ensure that a high level of flood protection is maintained. J. Program of works in the Kera basin to be completed by 1990.

7-4 c TABLE 7.1--Continued

Staged Alternative Stage I Stage II Stage III Service Area Service Area Service Area Drainage Basin 1 2 3 1 2 3 1 2 3 Putih Main channel CCD CCD N/A 3a CCD N/A 3a 3a N/A Local drains Submains CCD CCD N/A 3a CCD N/A 3a 3a N/A Street Res High Value CCD CCD N/A 3b CCD N/A 3b 3b N/A Res Low Value CCD CCD N/A 3b CCD N/A 3b 3b N/A Com High Value CCD CCD N/A la CCD N/A la 2a N/A Com Low Value CCD CCD N/A lb CCD N/A lb 2b N/A Badra Main channel N/A N/A N/A N/A N/A 4a N/A N/A 4a Local drains Submains N/A N/A CCD N/A N/A 3a N/A N/A 3a Street Res HigValue N/A N/A CCD N/A N/A CCD N/A N/A 4b Res Low Value N/A N/A CCD N/A N/A CCD N/A N/A 4b Com High Value N/A N/A CCD N/A N/A CCD N/A N/A 2a Com Low Value N/A N/A CCD N/A N/A CCD N/A N/A 2b

7-5 The recommended monitoring program should be developed giving consideration to the following items:

1. Parameters: - flood flow rates

- water quality

- areas inundated

- flood damage

2. Locations: - Primarily in major rivers and main drains

3. Methodology: - equipment and field installation

- sampling procedures and equipment

- frequency of observations

7.2.2.2 Channel and Drain Maintenance

Monitoring of operations and maintenance will continue to be an important element of drainage system management to ensure the fulfillment of drainage program objectives.

Work schedules and staffing requirements for the maintenance program will have to be continuously reviewed on the basis of the moni toring results and adjustments made as required to ensure that reasonable production standards are applied and met.

The organizational elements necessary to carry out this function are described in Section 8 •

7 .3 PHASED IMPLEMENTATION PROGRAM

Figure 7 .1 illustrates the phased implementation program for drainage and flood control.

Critical items which can be initiated prior to mid-1981 when con ventional international funding will become available have been identified as an immediate action program.

7.4 COSTS

The estimated capital and operation and maintenance costs of the foregoing program of works for the drainage system is summarized in Table 7 .2 and 7 .3.

7-6 -0

DRAINAGE IMPLEMENTATION SCHEDULE

C-3 m STAGE I STAGE II STAGE III ITEM REPELITA III REPELITA IV 1979/80 1980/81 1981/82 1982/83 1983/84 1984/89 1989/2000

LONG TERM PROGRAM PRELIMINARY PLANNING FEASIBILITY STUDIES PROJECT APPRAISAL - AGENCY BANK NEGOTIATIONS , REQUEST PROPOSALS .

SELECT CONSULTANTS - MOBILIZE - DESIGN TENDERS

KERA BASIN IMPROVEMENTS URBAN AREA CLEARING CLEANING DREDGING

- LOCAL DRAINS - MAIN DRAINS m - MAJOR RIVERS MONITORING DOWNSTREAN CLEARING CLEANING DREDGING CHANNEL IMPROVEMENTS - LOCAL DRAINS - MAIN DRAINS - MAJOR RIVERS C0, C2 m IMMEDIATE ACTION PROGRAM KERA BASIN IMPROVEMENTS -

I URBAN AREA CLEARING .LEANING DREDGING - -) MONITORING CHANNEL IMPROVEMENTS-LOCAL DRAINS

-- I m TABLE 7 .2

ESTIMATED CAPITAL COSTS FOR RECOMMENDED DRAINAGE MANAGEMENT SYSTEM

Estimated Capital Cost in Thousands of Rupiah Item 1979/80 1980/81 1981/82 1982/83 1983/84 1984/89 1989/2000

Kera basin improvements 290,000 720,000 870,000 4,470,000 - (570,000) (280,000) Urban area clearing, clean.ig, dredging Local drains 61,000 121,000 121,000 (121,000) (121,000) (60,000) Main drains 95,000 190,000 190,000 (190,000) (190,000) (95,000) Monitoring 6,000 12,000 12,000 (75,000) (12,000) (6,000) Downstream clearing, cleaning, dredging 270,000 - Channel improvements: - Local drains 184,000 607,000 647,000 3,589,000 10,885,000 (312,000) (253,000) (194,000) - Main drains 1,i00,000 2,200,000 - Major rivers 4,136,000

Sub Total 636,000 1,650,000 1,840,000 9,429,000 17,221,000 (698,000) (1,146,000) (635,000) Training Engineering & TechnicalAssistance 63,000 165,000 184,000 943,000 1,722,000 (70,000) (115,000) (64,000) Land 500 1,000 1,000 5,000 11,000 (1,000) (1,000) (500) Contingencies 105,000 272,000 304,000 1,557,000 2,843,000 (115,000) (189,000) (105,000)

Total 804,500 2,088,000 2,329,000 11,934,000 21,797,000 (884,000) (1,451,000) (804,500)

Note: - Costs at 1979 prices. - ( ) indicates immediate action program expenditures. TABLE 7.3

ESTIMATED OPERATION AND MAINTENANCE COSTS FOR RECOMMENDED DRAINAGE MANAGEMENT SYSTEM

Estimated Annual Operation and Maintenance Cost in Thousands of Rupiah Item 1979/80 1980/81 1981/82 1982/83 1983/84 1984/89 1989/2000

Proposed Improvements Kera Basin 1,000 2,000 4,000 10,000 10,000 Local Drains 36,000 25,000 23,000 22,000 20,000 18,000 16,000 Urban Area: Main Drains 20,000 14,000 13,000 11,000 10,000 9,000 8,000 Rivers 10,000 25,000 24,000 23,000 20,000 20,000 Downstream channels 25,000 17,000 15,000 13,000 Monitoring 12,000 12,000

Total 56,000 49,000 62,000 84,000 74,000 84,000 79,000

Note: - Costs at 1979 prices. SECTION 8

ORGANIZATION AND FINANCE

8.1 EXISTING ORGANIZATION

Responsibility for drainage in Medan is shared by the provincial major and city governments. The province assumes responsibility for city rivers such as the Deli, Babura, Belawan and Percut. Beyond the which ori boundaries, the lower reaches of some of the larger streams Within Med; ginate in Medan are also dealt with by provincial agencies. many of the the city government administers the drainage program with of goverl major capital works supported by the programs of senior levels ment such as INPRES. of On June 25 1979 a new organization structure for the department public works was enacted altering the drainage program administration shown in Figure 8.1 to that shown in Figure 8.2. The new organization and chart illustrates the close correlation that exists between drainage under street improvements in city operations. Drainage works are usually to traffic taken to accomodate road improvements initiated in response needs.

The scope of the proposed drainage program will require the initi drainage ation of projects based on drainage needs and close control of works carried out in conjunction with other programs.

8.2 RECOMMENDED ORGANIZATION

Drainage is no doubt an important element of new road construction. is an Close coordination between road works and other utility programs important element of urban utilities planning. However, the implementa tion of a comprehensive drainage program requires direct administrative For this continuity through each stage of the implementation process. recommended. reason the organization structure shown in Figure 8.3 is

Maintenance operations have been divided into three geographical operations in areas with one unit given responsibility for maintenance one in the a priority central area. Two other units will function; easterly and one in the westerly sections of the city.

8-1 A -0

C131 C= m mom rrn FORMER ORGANIZATION CHART cm DRAINAGE SECTION -

PUBLICWORKS DEPARTMENT

PLANNING AND DRAINS AND MONITORING RIVER CONTROL WORKSHOP OTHER SECTION SECTION SECTION SECTIONS

DRAINAGE mSUB SECTION m

m C1 SUPERVISION [SUPERVISION

OTHER SECTOR I SECTOR II SUB SECTIONS

c"3 C3

CEXISTING ORGANIZATION CHART DRAINAGE m

PUBUC WORKS DEPARTMENTI

ADMINISTRATION PLNNNGAN INEAC EAYQIPMN EVALUATION SUPERVISION MAINTENANEE SECTION SECTION SECTION ADSTIONE

ROADS AND ROADS AND ROADS AND VEHICLES I1 mBRIDGE___ S BRIDGES BRIDGES IHEAVYEQU IPIM m m

DRAINS DRAINS DRAINS WORKSHOP

'i m I -o SURVEYS PERMITS STORES a, r2 -4 m C -0

PROPOSED ORGANIZATION CHART DRAINAGE SECTION

C, PUBLIC WORKS AND UTILITIES PROGRMMINGDEPARTMENT IAMNSRTO COORDINATION AMNSRTO

OTHER SECTIONS DRAINAGE ECT I

PLANNING CONSTRUCTION MAINTENANCE

CONTRACTI I ADMINISTRATIONI SINSPECTIONj m MONITORINGEATR WARNING RELIEF DSTRN !I COORDINATION 'i C1CHANNEL WESTERN 1l mCLEARING CHANNEL KERA DISTRICT CCLEANING IMPROVEMENT BASIN DREDGING

DEINCETA m, -I DISTRIC 23 Drainage Section's Construction will become an important part of the either by Municipal forces operations. Construction may be carried out or by contract. and dredging program will The urban area channel clearing, cleaning which could be effectively represent a large steady long-term workload and equipment as may some components carried out by Drainage Section forces programs. The construction by of the channel improvement and Kera basin items should be considered contract of the remainder of the major work Section is proposed that and a construction division of the Drainage will provide for:

a Contract management

" Construction supervision

forces " Supervision of capital works carried out by Municipal

is also proposed which A monitoring, control and planning section could consist of the following components:

1. Monitoring

* Flood flow for areas subject to inundation " Flood warning and emergency services coordination

2. Programming which will * Develop capital works and maintenance programs be implemented by the construction and maintenance divisions.

3. Design drawing specifica * Preparation of designs and construction capital works tions and other contract documents for all items.

8.3 REVENUE AND EXPENDITURE

8.3.1 Existing Levels are shown in Revenue and expenditure for drainage in 1978/79 Table 8.1.

8-5 TABLE 8.1

DRAINAGE - REVENUE AND EXPENDITURE, 1978/79

Revenue Rp./Million

Driinage 8 Other Taxes (local & central) 116 Inpres funds 35 Total 159

Expenditure

Routine 68 Development 91 Total 159

Source: Dinas Pendapatan; Drainage Section, PWD; Dept. of Finance; Sub-Directorate, PMD.

8.3.1.1 Taxes

The major revenue source is local taxes, but only Rp. 8 million out of the total tax allocation of Rp. 124 million is from a specific drainage tax, the balance coming from the pool of other tax revenues.

Drainage tax is charged at the rate of Rp 200 per sq m for open drains which ar adjacent to a property and at Rp 300 per sq m for closed drains. An additional 30 percent per floor is added for multi-storey properties. In 1978 there were just under 15,000 properties enumerated as having drainage, of which one-third had closed drains. The most recent information available on the number of properties in Medan is the 1975 city census which gives the total of domestic properties as 153,000. No figure exists for industrial and commercial properties, but if the latter were included and allowance made for property growth since 1976 it is clear that the percentage of properties assessed for drainage tax is extremely low.

The revenue from drainage tax is well below potential, but by how much is difficult to estimate. This is for two reasons; firstly, the tax collection department (Dinas Pendapatan) is not necessarily informed when new drains are constructed and secondly, the taxes are often not collected from properties which are assessed. The revenue department estimates the collection rate at around 30 percent. There is no penalty for non-payment and arrears are not carried forward. Property owners, particularly with open drains, refuse to pay on the grounds that no service is provided; it is claimed that the drains are continuously blocked, causing flooding during periods of heavy rains.

On the basis of the current assessment (which is certainly under stated) the potential drainage tax revenue is Rp 26 million per annum; ar-tual collection is Rp 8 million. This means that most of the locally financed drainage expenditure is derived from other taxation sources.

8-6 In addition to local tax revenue, Inpres (central government) funds are made available for drainage purposes. In 1978/79 this amounted of to Rp 35 million, principally for development. The sub-directorate village development similarly have use of central funds for providing million for services in the kampungs. In 1978/79 this amounted to Rp 20 development and Rp 6,000,000 for routine expenditure.

8.3.1.2 Expenditure In Expenditure is categorised as either routine or development. Rp 20 practice', these definitions are somewhat fluid as approximately to have been million of "development'" expenditure in 1978/79 would appear expenditure for maintenance (routine) items. But however defined, drainage is totally inadequate to maintain a reasonable level of service.

8.3.2 Future Requirements a As just discussed, although drainage charges exist, they generate drainage services very low level of income. The result is that the current taxation. are almost entirely funded out of a mixture of local and national be The funding of the proposed drainage investments will need to finance. The undertaken on the basis of a combination of loan and grant by the extent exact structuring of the financing package will be determined costs and to which local tax receipts allocated to drainage can cover are not debt service commitments. Specific user charges for drainage experience in particularly suitable for revenue generation. The current failure. attempting to impose such charges has been almost a complete drainage is a With improved services, collection rates may improve but as costs. community service, taxes are a more appropriate method of recovering

8.3.2.1 Tax Revenue Required revenue The question still remains, however, of just how much tax Mfedan's could reliably and regularly be made available for drainage. and conditions; tax resources are severely strained under current practices particularly but considerable scope exists for improving this position, is now being in the areas of enumeration, assessment and collections. This of improving reviewed and recommendationswill be made on ways and means made are Kotamadya Medan's financial performance. If the recommendations to drainage acted on, it should be possible to increase the tax allocation to well beyond the existing local contribution of Rp 98 million. of funding The tax revenue requirements under various combinations Table 8.2 the and other financial assumptions have been calculated. In selected years annual tax revenues at constant 1979 prices are shown for but and in Table 8.3 the same data is shown assuming 10% inflatioi., converting back to 1979 prices.

8-7 TABLE 8.2

ANNUAL TAX REVENUE REQUIRED (RP. MILLION) TO COVER RECURRENT COSTS, INTEREST AND CAPITAL REPAYMENTS IN CONSTANT 1979 PRICES

% Loan/Grant 1980/81 1984/85 1988/89

100% Loan 75 1220 2584

75% Loan/25% Grant 75 938 1962

50% Loan/50% Grant 75 514 1026

TABLE 8.3

ANNUAL TAX REVENUE REQUIRED (RP.MILLION) TO COVER RECURRENT COSTS, INTEREST AND CAPITAL REPAYMENTS ASSUMING 10% INFLATION, EXPRESSED IN 1979 PRICES

% Loan/Grant 1980/81 1984/85 1988/89

100% Loan 83 903 1630

75% Loan/25% Grant 83 700 1246

50% Loan/50% Grant 83 319 861

Taking the averages of the two Tables, even under 50% loan/50% grant conditions the tax revenue requirement would increase to Rp. 416 million in 1984/85 and to Rp. 944 million in 1988/89. Under 100% loan conditions the figures become Rp. 1,062 and Rp. 2,107 million.

The recommendations resulting from the current review of Medanis financial performance should, if accepted and acted upon, result a sinifi cant increases in tax receipts. Assuming that the percentage of local taxation receipts available for drainage services continues at the cur rent level of around 3%, higher drainage revenues would accrue. But to attain the level required, even under 50% grant funding conditions, would require a four-fold increase in the local tax take. Alternatively, the percentage allocation to drainage could be increased. This may be possible, but given the clamour of competing claims for slices of the tax take, it would be imprudent to rely on any substantial increase in the drainage share.

8-8 8.3.2.2 Summary

The conclusion must be, therefore, that a sizeable grant element The pre will be required in the funding mix for drainage investments. munici cise proportion of this will be determined following the current financial apnraisal pal financial review and will be incorporated into the of the First Stage program (Section 10).

8-9 SECTION 9

THE RECOMMENDED FIRST STAGE DRAINAGE SYSTEM IMPROVEMENT PROJECT

9.1 GENERAL

As illustrated by Figure 9.1 flooding is a serious problem in Medan. Major floods have occured in 1956, 1965 and 1971. Whenever there is a heavy rainfall roads and low lying areas are flooded with consequent property damage, pollution of shallow wells and traffic interference. Even after relatively light rainfalls flooding often occurs because inlets and drains are choked with sediment, vegetation and refuse.

Most drainage improvements that have been carried out do not provide a high level of flood protection because of the relatively small capacity of the drains and infrequent maintenance. Urban development in flood prone areas also contributes to current flooding problems especially along the lower Deli River between Medan and Belawan. The drainage system also receives most of the grey waters and septic tank effluent produced in the study area which contributes to public health problems in the city. The presence of roadside open channels in high density commercial areas frequently creates conditions which make access to shops and other places of business inconvenient and unpleasant.

The strategy for the staged improvement of the existing drainage system, developed under the master plan investigations, provides for the immediate implementation of new drainage works in areas where current flooding problems are critical and the clearing, cleaning and dredging of existing channels to maximize their flood control potential. Once channels are cleared flood flows will be monitored to provide a basis for the detailed planning of future major drainage works.

The first stage of the master plan drainage program for Medan consists of the following items:

1. Kera Basin

The first stage of major improvements in the Kera Basin.

2. Urban Area

The first stage of a channel clearing, cleaning and dredging program.

9-1 \1 3. Monitoring

Monitor drainage system operation after initial channel cleaning and throughout the program period to provide basic design and performance evaluation data and to establish priorities for future channel improvements.

4. Channel Improvements

First stage of channel improvements in the urban area outside the Kera Basin. The program ot be coordinated with:

o The flood monitoring program " Road improvement and new road construction programs * Implementation of the sanitary sewerage program and other utility programs.

5. Flood Warning and Emergency Assistance

6. Control of Urban Development

7. Training and Technical Assistance.

Four levels of service have been selected for application in accordance with the needs of the various sections of the city as indi cated in Table 9.1. Three service areas were identified representing priority areas for drainage improvements based upon population and land use as shown in Figure 9.2. The application of service objectives for the recommended first stage drainage program is summarized in Table 9.2 and in the first priority area, Service Area No.1, in Figure 9.3.

9.2 DESCRIPTION OF THE FIRST STAGE DRAINAGE SYSTEM IMPROVEMENT PROJECT

9.2.1 Kera Basin Improvements

9.2.1.1 Main Drains

The characteristics of the existing drainage system in the Kera Basin are shown in Figure 9.4. The existing capacity of the main channel and its capacity requirements are illustrated in Figure 9.5. Four prio rity categories for improving the main channel of the Kera were selected as follows:

Priority Description

1 Clear clean and dredge existing channel except where major improvements are to be carried out in the first stag6.0 2 Channel improvements to presently unimpro ved portions of the channels in high den sity areas and where required to provide outlet.

9-2 PADCO-DACREA

Docurneon FIGURE I

LOCATION OF FLOOD PRONE AREAS

S*LEGEND . . .SITES WHERE REGULAR FLOODING OCCURS RAIL ROAD

-'"'-. MAJOR ROAD

p-- STUDY AREA BOUNDARY

* I

......

* I.

ENGINEERIr-SCI ENCE SINTI Documen Best Av11able TABLE 9.1

DRAINAGE MANAGEMENT SYSTEM - SERVICE OBJECTIVES

Description

Service Flood Flow Return Level Facilities Interval years Application

1 a Enclosed channel with full 5 Local street drains high density high value street improvements commercial districts. Enclosed channel with full Submains in commercial districts btenoed channelthf 2 Local street drains in high density lower street improvements value commercial districts 2 a Enclosed channel 5 Submains in medium and low density high value commercial districts

b Enclosed channel 2 Submains in medium and low density lower value commercial districts

3 a Lined open channel 5 Main drains and other submains in high density and medium density areas TABLE 9.2

FIRST STAGE DRAINAGE PROGRAM SUMMARy a

Service Area b

Drainage Basin 1 2 3

Lower Deli Main channel d CCDc CCD CCD Local drains Submains CCD CCD CCD Street Res High Value CCD CCD - Res Low Value CCD CCD - Com High Value CCD CCD - Com Low Value CCD CCD - Upper Deli Main channel Local drains Submains 3a 3a CCD Street Res High Value CCD CCD - Res Low Value CCD CCD - Com High Value CI') CCD - Com Low Value CwD CCD - Babura Main channel CCD CCD - Local drains Submains CCD CCD CCD Street Res High Value CCD CCD - Res Low Value CCD CCD - Com High Value CCD CCD - Com Low Value CCD CCD -

Notes: a. See Table 9.1 for definition of service objectives. b. Refer to Figure 9.2 for service area boundaries. c. CCD means clear clean and dredge existing channels. d. Submain improvements to be selectively initiatived in Stage I to correct specific problem situations.

9-6 TABLE 9.2- Continued

Service Area

Drainage Basin 1 2 3

Percut Main channel N/A N/A Local drains Submains N/A N/A Street Res High Value N/A N/A - Res Low Value N/A N/A - Com High Value N/A N/A - Com Low Value N/A N/A - Belawan Main channel N/A N/A Local drains Submains N/A N/A Street Res High Value N/A N/A - Res Low Value N A N/A - Com High Value O/A N/A - Com Low Value N/A N/A - Kerae Main channel 3a 3a 3b Local drains Submains f 3a 3a 3b Street Res High Value 3b 3b 4b Res Low Value 3b 3b 4b Com High Value la 2a 2a Com Low Value lb 2b 2b Sikambing Main channel N/A CCD - Local drains Submains N/A CCD - Street Res High Value N/A CCD - Res Low Value N/A CCD - Com High Value N/A CCD - Com Low Value N/A CCD -

e. Program of works in the Kera basin to be completed by 1990. f. In commercial areas submains on sWreets are to be constructed to street drain objectives.

9-7 \ TABLE 9.2 -Continued

Service Area Drainage Basin 1 2 3

Putih Main channel CCD CCD N/A Local drains Submains CCD CCD N/A Street Res High Value CCD CCD N/A Res Low Value CCD CCD N/A Corn High Value CCD CCD N/A Com Low Value CCD CCD N/A Badra Main channel N/A N/A N/A Local drains Submains N/A N/A CCD Street Res High Value N/A N/A CCD Res Low Value N/A N/A CCD Com High Value N/A N/A CCD Com Low Value N/A N/A CCD

9-8 i7i*

DE I

......

BiLAAN RIVER

IDCO-DACREA FIGURE

DRAINAGE SERVICE AREAS

LEGEND

SERVICE AREA: I g PRESENT HIGH DENSITY. HI( VALUE URBAN AREA (FIRST PRIORITY AREA) '" SERVICE AREA: 2 F 1 PRESENT MEDIUM DENSITY HIGH VALUE URBAN AREA -- Em (SECOND PRIORITY AREA) SERVICE AREA: 3 YEAR 2000 URBAN DEVELOPE (THIRD PRIORITY AREA)

YBOUNDARY 1- MAJOR DRAINAGE AREA

f -,it

A . ... ° 1 2

4 " "?...

( .\

Best Available Documen, ENGINEERING-SCIENCE -SINOTE1 // (\k 'IfrjIM

IA L

L. il RIVER

PADCODACRE FIGURE 9.3

- IS DRAINAGE SRIEOBJECTIVES

LEGEND

... ,1,..,.../ :. sERvicE LEVEL z

LEVEL 2 j 4 -BOU.AR-SESERVICE SERVICE LEVEL I1

I: L~-~' I y''.1 SERVICE LEVEL 3

SERVICE LEVEL 4 .3 * Z

, -- BOUNDARY SERVICE AREANOI

BOUNDARY SERVICE AREA N02

, . . - BOUNDARYMAJOR DRAINAGE AREAS

PRIORITY LOWINtOME AREA

_X_ BUILT UPAREA L78

KA 06,, I.I

ENIERN-CEC - SIOTC 0 2 0 0.2 0.6 1.0 1.4 ',R FN

JJJIIIC

DE VER

sl ING 7 PADCO-OACREA FIGURE 9.4

EXISTING DRAINAGE SY,,TEM IN KERA BASIN C/p.

LEGEND

- CONCRETE LINED CHANL C0000 CONDITION)

Meomoi. CLOY-*E0CONDUIT

*eeeeweee CONCRETELINED CHANNEL B(UICONDITION)

deIsessees EARTH CHANNEL (OOO CONDITION)

- -i- EARTH CHANNEL(BAD CONDITION)

SAJA ORMANAGAREA .01MOARY

-O.NDARY OF SRVIC AREA I

*OLWDARYOF SERVICEAREA a

'* 2 "..V -. o20METRE COoUNR LINE

==cRIVERS

~' ...... s....,.

zi "11

KILME-E

iiTC ENIEEIGSCEC -

Ajest5-- AviabaDnrmn

.N IEE0. 0 IE 0O PROJECTED STORM RUNOFF FOR KERA RIVER BASIN

20 YEARS

10 YEARS 5 YEARS 400 - 2 YEARS PEAK STORM RUNOFF

m 300 EXISTING RIVER CAPACITY WITHOUT FREE BOARD

I. 0 Z 200 EXISTING RIVER CAPACITY WITH FREE BOARD

E 100

I 60 *1~~~~~~~~~-1 ~ ------

0 5 10 15 20 DISTANCE, Km Priority Description

3 Channel improvement in low density areas.

4 Upgrade standard of existing lined channels which are now in good condition.

The proposed improvements to the main channel of the Kera are summarized in Table 9.3 and Figure 9.6. Typical channel cross sections from station 48 to K4 are shown in Figure 9.7.

Drainage improvements in the main channel below station K4 are now being planned by the Provincial Department of Public Works and are expected to be carried out early in 1980.

9.2.1.2 Submain Drains

Within the Kera Basin improvements to submain drains are proposed as summarized in Table 9.4 and Figure 9.6.

Priorities for implementation have been based upon the require ments of other programs such as KIP and road improvement projects, existing drainage prcblems and the conditions of existing drains. Typical sections of submain drains to be applied to the various service levels are illustrated in Figures 9.8 and 9.9.

9.2.1.3 Local Drains

In the Kera Basin the implementation of local street and foot path drains will be done as part of the KIP program. Street improve ments inluding ring road construction are being planned and it must be ensured in the planning of these works that adequate provisions for drainage are included to the standards established by the drainage program. Typical cross sections of local street and footpath drains are included in Figure 9.10.

9.2.2 Urbaix Area Channel Clearing Cleaning and Dredging

9.2.2.1 River Channels

Within the urban area flooding associated with the lower Deli can be alleviated by clearing cleaning and dredging the existing channel of the lower Deli River between stations Band 9 (refer to Figure 9.1).

Clearing cleaning and dredging in the upper Deli River above its confluence with the Babura River and the Babura River has a much lower priority because of the relatively large existing channel capacity.

9.2.2.2 Main Drains

Priorities for clearing cleaning and dredging existing main channels in the urban area lie firstly with the Kera and the Putih and secondly with the Sikambing based primarily and the relative density of existing development in drainage service areas 1 and 2.

9-16 TABLE 9.3

KERA BASIN SCHEDULE OF PROPOSED IMPROVEMENTS MAIN CHANNEL

Length Required Item Priority River Description Capacity No. Rank No.RanRechReach ExistingxisingConitin Condition PopoedProposed Improvementsmprvemnts (m) (cu m/s)

1* 1 G - 48 Lined Channel Clearing, Cleaning and 700 159 Good Condition Dredging 2* 1 49 - G Lined Channel, Clearing, Cleaning and 1,000 130 Good Condition Dredging 3* 1 50 - 49 Lined Channel Clearing, Cleaning and 1,100 101 Good Dredging 4* 1 51 - 50 Lined Cbannel Clearing, Cleaning and 1,600 41 Guod Dredging 5 * 53 58 Lined Channel Clearing, Cleaning and 750 91 Good Dredging. Repair Control Gates 6 * 1 46 - K4 1 Unlined Channel Enlarge and Line Existing 2,150 273 Poor Channel 7 * 2 47 - 46 Unlined Channel Enlarge and Line Existing 2,050 239 Channel 8 3 48 47 1 Unlined Channel Enlarge and Line Existing 1,200 188 Good Channel 9 3 K1 53 Unlined Channel, Clearing, Cleaning and 1,700 52 Fair. Dredging TABLE 9.3- Continued

Item Priority River Description Length Required No. Rank Reach Existing Condition Proposed Improvements Capacity (m) (cu m/s)

10 4 G - 48 Lined Channel, Enlarge and Line Existing 700 159 Good Condition Channel 11 4 49 - G Lined Channel, Enlarge and Line Existing 1,000 130 Good Condition Channel 12 4 50 - 49 Lined Channel Enlarge and Line Existing 1,100 101 Good Channel 13 4 51 50 Lined Channel Enlarge and Line Existing 1,600 41 Good Channel 14 53 - 58 Lined Channel Enlarge and Line Existing 750 91 Good Channel 15 4 53 - 52 Lined Channel Enlarge and Line Existing 2,000 91 Good Channel 16 4 53 - 52 Lined Channel Clearing, Cleaning and 2,000 91 x od Dredging

1. Because improvements are to be carried out immediately channel clearing cleaning and dredging will not be necessary for the Kera station 47 to K4. * Items included in first stage. a' .' *.~.

L. V .9

K 45

K- I *6 K- IS 'I 0 1 'I I ,~rd

II I I

9. I

'K-IS ~ K ! ~K

* a iji I * - w p *

K-S K K-a \\

I a a - It

. *-.

* *a.* j, *. .~ a 0~'~ /

13 * p 0

__ - ., 4 Iqy - C

Z *-'r-~

. I .5 ~~I1

I i ~. ~1,

-4-U.

p a,

PADCO-DACREA FIGURE 9.6

PROPOSED DRAINAGE SYSTEM

.._t_.._---. /.,:

I LEEVO

* *OPEN CHANNEL -MINOR SUBMAIN

'l1 OPEN CHANNIL - MAJOR SUB MAIN

mm-- WDE CONDUIT- MINOR SUB, MAN

CLOSEDCONDUIr - MAJORsuE MAIN

4 MXJOR DRAINAMAREA BOUNDARY

a4' i UOUNDARYB OF SERVICE AREA I

ino OuARY Or WViCE AREA a

- * 4&I 30 METERS COUTOUPLINE

'1* REICOMMINIEDFIST STAIE IMPROVEMUIT

"IP AREA

~ *S*.*,.&LOW INCOMEPRIORITY AREA

BMWUILT U.PAREA 1978

.. . V ... -. , .. !lA,2 4 AI . . -.-..

I,,,

0.2 0 03 0.6 10 IA

KILOMETRES

ENGINEERING-SCIENCE - SINOTECH17 FIGURE 9.7

TYPICAL CROSS SECTION KERA MAIN CHANNEL

_CORETE BLOCKS iH 14

h CO(:ETE

CHANNEL DIMENSIONS REACH H(m) 8 (m) h(m) b (m) 48-47 5.20 3.75 0.20 0.40

47-46 5.80 7.15 0.20 0.70

46 - K4 5.70 9.95 0.25 1.00

ALL OF THE DIMENSIONS ARE PRELIMINARY

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH\, TABLE 9.4

KERA BASIN SCHEDULE OF PROPOSED IMPROVEMENTS SUBMAIN DRAINS

Length Kampungs Item Priority Identity Classification in Triutar in Tributary No. Rank No. Major Minor Description (m) Area

1 K-191,3 0 Clear Clean Dredge 750 Pandau Hulu II, Sei Rengas II, Kotamatsum I, Kotamatsum II, II. 2* 1 K-13 3 Sukaramai 0 Enlarge and Line 1,100 Kocamatsum II, Existing Channel Kotamatsum I, 3*t3 1 K-15 3 Sukaramai II. 0 Enlarge and Line 750 Kotamatsum I, Existing Channel Kotamatsum II, 4* K-143 0 Enlarge Kotamatsum III. and Line 500 Kotamatsum I. Existing Channel 5* K-16 2,3C Build New Closed 250 Kotamatsum I, Conduit Kotamatsum II, Kotamatsum III. 6 1 K-17, 3 C Build New Closed 1,250 Kotamatsum I, Conduit Kotamatsum II, Kotamatsum III, Sei Rengas II. TABLE 9.4- Continued

Length Kampungs Item Priority Identity Classification in Tributary No. Rank No. Major Minor Description (m) Area

7* K-18 0 Clear Clean Dredge 650 Sei Rengas II, Kotamatsum I, Kotamatsum II, Sukaramai II. 8 1 K-12 0 Enlarge and Line 950 Tegal Sari I, Existing Channel Tegal Sari II, 9* 1 K-21 2' 3 C Build New Closed 650 Sei Kera Hilir Conduit *3 10 1 K-li 0 Line Existing 1,000 Tegal Sari II, Channel Tegal Sari I. 11 1 K-23 3 0 Build New Open 1,250 Sidorame Barat Channel Sidorame Timur

12* 1 K-24 3 0 Build New Open 650 Sei Kera Hilir Channel 13 K-1 ,2,3 13 1 K-10 1 C Build Closed 1,700 Tegal Sari II, Conduit Tegal Sari I, Sukaramai II, Pasar Merah Barat, Teladan Timur, Sudirejo I, Teladan Barat Pasar Merah Timur, Sukaramai II. TABLE 9.4- Continued

Item Prrit- Length Kampungs Identity Classification in Tributary Nc,. 'No. Major Minor Description (m) Area

14 1 K-82,3 C Build Closed 1,200 Pasar Merah Barat Conduit Pasar Merah Timur 15 1 K-3 3 0 Build Lined Open 670 Tegal Sari II Channel 16 1 K-22 1,2 C Build New Closed 750 Sidodadi Conduit 17 2 K-20 C Build New Closed 950 Pandau Hulu I, Conduit Pandau Hulu II, Pusat Pasar. 18 2 K-91 2 , 0 Build Closed 450 Pasar Merah Timur, Conduit Teladan Timur, Sudirejo I, Teladan Barat. 19 2 1 K-4 0 Build Lined Open 600 Teladan Timur, Channel Sudirejo I. 20 2 K-37 2 C Build Closed 650 Pulau Brayan Darat, Conduit Glugur Darat, Tegal Rejo. 21 2 K-36 2 C Build Closed 750 Pulau Brayan Darat, Conduit Glugur Darat, Tegal Rejo. 22 2 K-35 2 C Build Closed 650 Pulau Brayan Darat, Conduit TABLE 9.4 - Continued

Length Kampungs rt-i Prioltv Identity Classification in Tributary No. Ranik No. Major Minor Description (m) Area

23 2 K-32 2 C Build Closed 750 Indra Kasih Conduit 24 3 K-7 0 Enlarge and Line 650 Teladan Timur, Existing Channel Teladan Barat, Sudirejo I. 25 3 K-6 0 Line Existing 400 Teladan Barat, Channel Teladan Timur. 26 3 K-5 0 Build Lined Open 600 Teladan Timur, Channel Sudirejo I. 27 3 K-26 0 Build New Open 700 Sidorejo Channel 28 3 K-30 0 Build New Open 750 Tegal Rejo, Channel Glugur Darat, Durian. 29 3 K-29 0 Build New Open 750 Glugur Darat, Channel Durian, Tegal Rejo. 30 3 K-28 C Build Closed 1,300 Durian, Conduit Glugur Darat. 31 3 K-27 0 Build New Open 1,300 Sidorame Barat, Channel Tegal Rejo. 32 3 K-2 0 Build Lined Open 1,250 Binjai Channel TABLE 9.4- Continued

Item Priority Identity Cla-sification Length Kampungs No. Rank No. Major Minor Description im) Area

33 2 K-1 0 Build Line Open 950 Sudirejo II. 34 3 K-34 Channel C Build Closed 950 Gelugur Darat, Conduit Pulau 35 3 Brayan Darat. K-33 0 Build New Open 950 Tegal Rejo, Channel Pulau Brayan 36 3 K-39 Darat. 0 Build Open Channel 700 Pulau Brayan Bengkel. 37 4 K-25 0 Build New Open 1,350 Sidorejo Channel 38 4 K-31 0 Build New Open 950 Indra Kasih Channel 39 4 K-42 0 Build New Open 1,250 Pulau Brayan Bengkel. Channel 40 4 K-41 0 Build New Open 750 Pulau Brayan Bengkel. Channel 41 4 K-38 0 Build Open Channel 700 Pulau Brayan Bengkel. 42 4 K-40 0 Build New Open 400 Tanjung Mulia Channel TABLE 9.4 - Continued

Length Kampungs Item Priority Identity Classification in Tributary No. Rank No. Major Minor Description (m) Area

43 4 K-46 0 Build New Open 4,400 Sei Kera Hulu Channel

44 4 K-45 2 C Build Closed 750 Sei Kera Hulu Conduit 2 45 4 K-43 C Build Closed 550 Sei Kera Hulu Conduit

2 46 4 K-44 C Build Closed 800 Sei Kera Hulu Conduit

C : Closed Conduit. 0 : Open Channel. 1 : Same Route as Trunk Sewer Line. 2 : Drains Under Proposed Major Roads. 3 : Drains Serving Kampung Improvement Program Areas. FIGURE 9.8

TYPICAL CROSS SECTION SERVICE LEVEL 1

BUILDING LINS

,]z.., NEW MAE ENI" WIDTH,,

; NEW SIDEWALK

STORM SEWER CATCH BASI

CONNECTION PIPE,

LEGEND

EXISTINGRE

POSSIBLE FUTURE PROFILE

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH FIGURE 9.9

TYPICAL CHANNEL CROSS SECTION SERVICE LEVEL 3

SBUILDING LINE

r--r--i LINED OPEN DITCH-I STORM SEWER-z..I I SUBMAIN - SANITARY SEWER

TYPICAL CROSS SECTION SERVICE LEVEL 2

H _ __H

CONCRETE BLOCKS

bt GRAVEL BED 1--0 1:30

PADCD-DACREA ENGINEERING-SCIENCE - SINOTECH FIGURE 9.10

H0 5. H5 H 1 H 5 ~ 0Ij 15~ 20j 22 15+~ 15+t 22

a. PLASTER

15I 15 RI L AS ERR "J"P-'CONCRETE 2. .

SCONCRETE

5 !15 ]1 ,IS,SERVICE LEVEL 3

LINED OPEN CHANNEL LINED OPEN CHANNEL UNIT s Cm UNIT sCm

1,.H 15 H

4-- (0

SERVICE LEVEL 4 30

UNIT: Cm UNLINED OPEN CHANNEL

TYPICAL CROSS SECTIONS OF STREET AND FOOTPATH DRAINS

PADCO-DACREA ENGINEERING-SCIENCE - SINOTECH \4)V 9.2.2.3 Submain Drains

Outside the Kera Basin and within the urban area priorities for channel clearing cleaning and dredging are primarily associated with density of development ,iithin each of the drainage service area boundaries.

Although outside the urban area boundary the submains of the upper Bedra Basin require improvement to alleviate flooding affecting the Binjei road and clearing cleaning and dredging of submains has been included as a 3rd priority item.

9.2.2.4 Local Drains

Priorities for the clearing cleaning and dredging of local drains must be based on field inspections carried out as part of the implemen tation phase with highest priority based on flooding frequency, density of development and channel condition.

9.2.2.5 Summary

A summary of priorities for channel clearing, cleaning and dredging is given in Table 9.5

9.2.3 Monitoring

9.2.3.1 Flow Recording and Inundation Records

Further basic flood flow data is required to complete the evalua tion of flooding problems especially for the lower Deli River.

The recommended monitoring program should be developed giving consideration to the following items:

1. Parameters : • flood flow rates * water quality * areas inundated • flood damage

2. Locations : primarily in major rivers and main drains

3. Methodology : • equipment and field installation * sampling procedures and equipment * frequency of observations

9.2.3.2 Channel and Drain Maintenance

Monitoring of operations and maintenance will continue to be an important element of drainage system management to ensure the fulfill ment of drainage program objectives.

9-31 TABLE 9.5

SCHEDULE OF URBAN AREA CHANNEL CLEARING, CLEANING AND DREDGING

Priority Item Rank Description

1 1 Main Channel - Kera

2 1 Main Channel - Putih

3 1 Main Channel - Sikambing

4 1 Submains - Deli Basin Service Area 1

5 1 Submains - Babura Basin Service Area 1 6 1 Street and Foot- - Service Area 1 path Drains 7 2 Main Channel - Lower Deli 8 2 Submains - Deli Basin Service Area 2 9 2 Submains - Babura Basin Service Area 2 10 2 Submains - Sikambing Basin Service Area 2 11 2 Street and Foot- - Service Area 2 path Drains 12 3 Submains - Service Area 3 Bedra Basin 13 3 Street and Foot- - Service Area 3 path Drains 14 4 Main Channel - Upper Deli 15 4 Main Channel - Babura

9-32 9.2.4 Other Drainage Improvements

Outside of the Kera Basin major drainage improvements beyond channel clearing cleaning and dredging are considered essential for submains in certain priority areas associated primarily with KIP and road improvement projects. These works are summarized in Tables 9.6 and 9.7.

9.2.5 Flood Warning and Emergency Assistance

In areas where measures are not taken to avoid flood damage precautions can be taken to ensure that damage is minimized and other effects of flooding are mitigated. These include:

* Stream flow monitoring and warning

* Assistance with evacuation

• Emergency health care, food and accommodation for flood victims

* Assistance with clean up operations.

The role of the drainage organization would be to provide warning based on measurements obtained under the monitoring program and to assist in coordinating the efforts of existing agencies. In practice a flood warning system would be most practical for the lower reaches of the main rivers where flood conditions are not related primarily to local storms. The city's involvement would therefore be limited to the lower Deli River.

9.3 SOCIAL AND ENVIRONMENTAL CONSIDERATIONS

9.3.1 Population Served

Table 9.8 summarizes the population served by the first stage drainage program.

Major drainage improvements are concentrated in the Kera Basin in which 37 percent of the total 1985 population, including 41 percent of the total low income group is located.

Beyond the Kera Basin in service area No. I improvements to the main channels and submain drains are planned for the Deli, Babura, Putih, and Sikambing drainage areas affecting approximately a further 20 per cent of the total population and 18 percent of the low income group.

Within service area No.2 approximately a further 20 percent of the total population including 20 percent of the low income group will benefit from clearing cleaning and dredging of existing channels in the Putih and Sikambing drainage areas and at Belawan.

9-33 TABLE 9.6

DELI DRAINAGE AREA SCHEDULE OF OTHER DRAINAGE IMPROVEMENTS

Item Length Kampungs Priority Identity Classification in Tributary No. Rank No. Major Minor Description (m) Area

1* 1 D-5 2,3 C Build Closed 450 Pasar Merah Barat, Conduit Sukaraja.

3 2 * 1 D-6 2, C Build Closed 350 Sukaraja, Teladan Barat, Pasar Merah Barat, Sei Mati. 3 * C Improve Existing 1,100 Teladan Barat, Channel to Closed Pasar Merah Barat. Conduit 4 * 1 D-7 1,2,3 C Build Closed 950 Mesjid, Conduit Pasar Baru, Kotamatsum 5 * 3 III. 1 D-8 2, C Build Closed 450 Pasar Baru, Aur, Mesjid, Kotamatsum III. 6 2 2 D-18 1, C Build Closed '00 Gelugur Kota Conduit 2 7 2 D-24 1, C Build Closed 00 Kesawan Conduit 8 2 D-23 0 Enlarge and Line 1,000 Sei Agul Existing Channel TABLE 9.6- Continued

Length Kampungs item Priority Identity Classification in Tributary No. Rank No. Major Minor Description (m) Area

9 2 D-22 2 C Build Closed 800 Sei Agul Conduit 10 2 D-25 1,2 C Build Closed 900 Aur, Conduit Kesawan. 11 2 D-26 0 Enlarge and Line 550 Madras Hulu, Existing Channel Hamdan, 2 Jati. 12 2 D-27 C Build Closed 450 Jati Conduit 2 13 2 D-19 C Build Closed 650 Sekip Conduit 14 2 D-14 C Improve Existing 500 Durian, Channel to Closed Gelugur Kota. Conduit 15 2 D-13 C Improve Existing 350 Durian Channel to Closed Conduit 16 2 D-11 C Build Closed 300 Durian Conduit 2 17 2 D-4 0 Build New Open. 900 Sei Mati, Channel Sukaraja. TABLE 9.6- Continued

Item Priority Identity Classification Length inKampungsTributary No. Rank No. Major Minor Description (m) Area

18 2 D-12 1 0 Build New Open 800 Durian Channel 19 2 D-16 1 C Build Closed 1,100 Pasar Baru, Conduit Sidodadi, Durian, Kesawan, 20 2 Gang Buntu. D-21 0 Enlarge and Line 200 Sei Putih Timur, Sekip. Existing Channel Silalas, 21 2 D-20 0 Enlarge and Line 450 Sei Putih Timur, Existing Channel Sekip. 22 2 D-17 0 Enlarge and Line 200 Pasar Baru, Existing Channel Sidodadi, Durian, Kesawan, 23 2 Gang Buntu. D-15 1 C Replace the Existing 900 Pasar Baru, Drain Gang Buntu. 24 2 D-10 C Replace the Existing 1,600 Gang Buntu, Drain Sidodadi, Durian, Sei Rengas I, Pasar Baru, MesJ id, Pusat Pasar Pandau Hilir TABLE 9.6 - Continued

Length Kampungs Itern Priority Identity Classification in Tributary No. Rank No. Major Minor Description (m) Area

25 2 D-9 C Replace the Existing 950 Sei Rengas I, Drain Pasar Baru, Gang Buntu, Mesjid, Pusat Pasar. 26 3 D-1 0 Enlarge and Line 1,100 Siti Rejo II, Existing Channel Sudi Rejo II, Sudi Rejo I. 27 3 D-2 0 Enlarge and Line 1,500 Siti Rejo II, Existing Channel Siti Rejo I. 28 3 D-30 0 Build New Open 450 Polonia Channel 29 3 D-29 0 Build New Open 400 Polonia Channel 30 3 D-28 0 Build New Open 1,000 Polonia Channel

* Included in first stage program. C : Closed Conduit. 0 : Open Channel. 1 : Same Route as Trunk Sewer Lines 2 : Drains under proposed major roads. 3 : Drains Serving Kampung Improvement Program Areas. TABLE 9.7 BABURA DRAINAGE SCHEDULE AREA OF OTHER DRAINAGE IMPROVEMENTS

No. Rank Item Priority IdertityNo. MajorClassification Minor Description Length Kampungs (in) Area in Tributary 1 2 B-8 0 Enlarge and Line 150 Anggrung, 2 2 b B- 6 C Existing Channel Build Closed Conduit Polonia. 400 Polonia 2 -5BbC Instead of Existing B-5b hann el C Build Closed Conduit 700 Polonia ~Channel Instead of Existing 4 B-15 Build Closed Conduit Instead 500 Petisah Tengah of Existing 5 2 B-14b Drain C Build Closed Conduit 1,000 Petisah Tengah Instead 6 of Existing 3 B-13 Drain C Build Closed Conduit 700 Petisah Tengah Instead of Existing 7 3 B-12 C Build Closed Conduit 8 3 B-il 800 Madras Hulu C Build 9 Closed Conduit 700 3 B-10 C Petisah Hulu Build Closed Conduit 10 3 B-9 200 Darat 0 Enlarge and Line 600 Darat Existing Channel / 0 TABLE 9.7- Continued

Length Kampungs Item Priority Identity Classification in Tributary No. Rank No. Major Minor Description (m) Area

11 3 B-7 0 Enlarge and Line 400 Polonia Existing Channel

12 3 B-4 0 Build New Open 650 Polonia Channel 13 3 B-2 C Build Closed Conduit 750 Padang Bulan

14 4 B-3 C Build Closed Conduit 300 Padang Bulan to Connect Existing Channel 15 4 B-1 0 Build Nv-- Open 850 Titi Rantai Channel

Closed Conduit I :Open Channel TABLE 9.8

DRAINAGE MANAGEMENT SYSTEM POPULATION SERVED 1985

Percent of total of population Service Area Service Area Service Area 1 2 3

Drainage High Med. Low High Med. Low High Med. Low Area Total Income Income Income Income Income Income Income Income Income

Kera 37 - 4 14 - - 10 - - 8 Deli 22 - 4 9 - - 4 - - 3 Babura 7 - 1 1 - - 1 - - 2 Putih 6 - - 4 - - - N/A N/A N/A Sikambing 10 N/A N/A N/A - 2 5 - - 2

Bedra 4 N/A N/A N/A - - -2 Percut 7 N/A N/A N/A N/A N/A N/A - - 6 Belawan 3 N/A N/A N/A - - - - - 2 Belawan Area 4 N/A N/A N/A - - 4 N/A N/A N/A

Total 100 2 9 28 1 3 26 3 3 25

( In service area 3 clearing cleaning and dredging in the Bedra drainage area will improve flooding conditions along the Binjei road and in the Perumnas I area will benefit 23 percent of the population and 21 percent of the low income group.

9.4 ECONOMIC CONSIDERATIONS

Engineering materials from foreign sources which could be used in the recommended drainage program include high quality larger diameter reinforced concrete pipe and special excavation equipment used for pipe line excavation and for ditch cleaning such as the Herder ditch cleaning machine used in the GOI/Netherlands solid wastes program at Pontianak. In this section the local manufacture of engineering materials and the use of labour intensive methods are examined from the standpoint of the benefits that would apply to the local economy.

Plain concrete pipe is manufacutred in Medan by local small scale industry in diameters up to 1000 mm and pipes of diameters up to 1200 mm dia have been cast at the job site for use in drain construction for recent roadway rehabilitation projects in Medan such as on Jalan Thamrin. However precast conduits of the standard required for the con struction of major drainage works are not available in Medan at the present time.

Although most of the drains in Medan will be open channels a significant quantity of large diameter high quality reinforced concrete pipe will be required for buried drainage conduits as well as roadway and access culverts. A concrete products plant which could produce pipe to the required standard could also produce precast linings for small open channels. Alternatively underground conduits could be con structed by labour intensive methods such as cast in place conduits or brick sewers.

Figure 9.11 summarizes the cost factors associated with the various types of drainage pipeline construction in Medan under current labour and material prices.

The analysis shows that the use of high quality precast rein forced concrete pipe manufactured in sizes up to approximately 2000 mm results in lower overall pipeline construction costs than the use of cast-in-place conduits. The use of hand methods rather than machine for excavation and backfill results in a relatively small reduction of pipeline installation costs and at least in the short term labour inten sive hand excavation methods can be considered.

9.5 OPERATION AND MAINTENANCE

9.5.1 Organization

On June 25, 1979 a new organization structure for the department of public works was enacted altering the drainage program administration; this has been shown in Figure 8,1 & 8,2. The proposed modifications to this have been discussed in 8.2 and the revised organization structure shown in Figure 8.3. 9-41 FIGURE 9.11

1000. 800.

600. C.P.C CAST IN PLACE CONDUIT 400 P.R.C.P: PRECAST REINFORCED CONCRETE PIPE

400 so 100 80

60 E I.TOTA COS FORC,PCBY MACHINE EXCAVATION . 40. 2.TOTAL COST FOR C.RC BY HAND EXCAVATION . --3.COST OF C.P.C ' - 4.TOTAL COST FOR RR.C.P 1BY MACHINE EXCAVATIOIN - 5. TOTAL COST FOR P.R.C.P BY HAND EXCAVATION 0 20 -6. COST P.R.C.P

. 0 ' o 6.

4 7 EXCAVATION COST BY MACHINE. FOR C.P.C - EXCAVATION COST BY HAND FOR C.R C - 9.EXCAVATION COST BY MACHINE FOR PR.C.P

2 - IO.EXCAVATION COST BY HAND FOR P.R.C.P

I I 2 3 4 5 6 DISCHARGE, cu.m/s

COMPARATIVE COST OF LABOR INTENSIVE METHODS

NOTE I.UNSKILLED LABOUR DISCOUNTED PY A FACTOR OF 0.7 2.PIPE SIZE RANGE 200mm TO 2000mm PAnCO-DACREA ENGINEERING-SCIENCE - SINOTECH 9.5.2 Staffing Requirements

Present and proposed 1985 staffing levels are shown in Table 9.9

TABLE 9.9

STAFFING REQUIREMIENTS

Proposed Staff Present Positions Requirement Staff *

Head, Drainage Section 1 Secretary 1 Clerk 1 Typist 2

Planning 12 Planning Engineer I Design Engineer 1 Drainage Technologist monitoring 1 Drainage Technologist 3 Draftsmen 3 Surveyor 1 Survey Assistants 4

Construction 12 Construction Engineer 1 Senior Project Engineer 1 Project Engineers 4 Inspectors 8 Surveyors 2 Survey Assistants 8 Channel Clearing Cleaning and Dredging crews (4) Superintendent 1 Foreman 4 Drivers 8 Laborers 20 Channel Improvement Force Account crews (2) Superintendent 1 Foreman 2 Drivers 4 Laborers 20

9-43 TABLE 9.9 - Continued

Proposed Staff Present Position Requirement Staff *

Kera Basin Improvements Superintendent 1 Foreman 3 Drivers 6 Laborers 30

Maintenance 97 Maintenance Engineer 1 Superintendent 3 Foreman 12 Drivers 24 Laborers 120

Total 303 121

* About 50 percent of positions are filled at the present time.

9.5.3 Training Programs

Staff training will be necessary to prepare technical and super visory personnel for their duties .inimplementing the drainage program. The following training program elements are proposed:

" Eefresher Courses - Part time attendence at the University of North Sumatra and the Medan Technical High School (STTM)

* On the Job Training - Staff seminars by specialist advisors

- Counterpart training with design consultants

Subject material should cover:

0 Urban hydrology including the collection and analysis of rainfall and streamflow data * Design methodology for determing the required capacity of urban storm drains

* Hydraulic design of open channels and closed conduits for the conveyance of storm runoff

0QAI Physical design standards for conduits and appurtenances

Methodology for determining loads on buried conduits and for the strength design of reinforced concrete conduits

9.6 ESTIMATED COST AND RECOMMENDED IMPLEMENTATION SCHEDULE

9.6.1 Capital Costs

The estimated capital cost of the proposed first stage drainage works is summarized in Table 9.10. Expenditure by year during Repelita III is given in Table 9.11. As costs are expressed in January, 1980 prices. Land costs, engineering costs and contingencies are excluded. It should be noted that the first stage program now recommended differs slightly to that proposed as part of the master plan projections (Table 7.2). This is a result of master plan review meetings held with the GO1 and the ensuing requirement to concentrate the program even more heavily than before on maximising benefits to the urban poor

TABLE 9.10

SCHEDULE OF CAPITAL COST (Thousand of Rupiah)

Item Quantity Cost

1981/1982 - Kera Basin Improvement

Submains

- K13 1100 m 223,000

- K15 750 m 136,000

9-45 \4 TABLE 9.10 - Continued

Item Quantity Cost

Urban Area Channel Clearing Cleaning and Dredging Main Drains - Kera Stn. 53 to 48* 6,400 m 39,000 - Putih 5,600 m 17,000 - Sikambing 14,100 m 83,000 Local Drains - Service Area No.1 L.S. 282,000 Monitoring L.S. 96,000

Other Drainage Improvements Submains - D5 450 m 174,000 - D6 350 m 170,000

1981/1982 Vehicles L.S. 47,000

Sub Total 1981/1982 1,267,000

1982/1983 - Kera Basin Improvements Main Channel Enlarge and line existing channel

- Stn 47 to 48 1,200 m 188,000 - Stn 46 to 47 2,050 m 703,000 Submains

- K 14 500 m 106,00n - K 16 250 m 57,000 - K 17 1,250 m 496,000 - K 18 650 m 142,000

Urban Area Channel Clearing Cleaning and Dredging Local Drains Service Area No.2 L.S. 217,000

9-46 TABLE 9.10- Continued

Item Quantity Cost

Downstream Channel Clearing Cleaning and Dredging - Lower Deli Station B to 9 9,600 m 235,000 Monitoring L.S. 29,000 Other Drainage Improvements Submains - D3 1,100 m 422,000 Vehicles L.S. 47,000

Sub Total 1982/83 2,642,000

1983/1984 - Kera Basin Improvements Submains - K12 950 m 200,000 - K21 650 m 108,000 - K11 1000 m 182,000 - K23 1250 m 248,000 - K24 650 m 116,000 Main Channel Enlarge and Line Existing Earth Channel - Stn 46 to K4 2150 m 1,065,000

Urban Area Clearing Cleaning and Dredging Local Drains Service Area 3 L.S. 221,000 Monitoring L.S. 21 000 Other Drainage Improvements Submains - D7 950 m 215,000 - D8 450 m 132,000 Vehicles L.S. 47,000

Sub Total 1983/1984 2,555,000 Grand Total 6,464,000

Includes repairs to diversion gates at 52-58.

9-47 TABLE 9.11

SCHEDULE OF CAPITAL EXPENDITURE - DRAINAGE Itillions of Rupiah - 1st Jan 1980 Prices

1981/82 1982/83 1983/84 Total Item C S T C S T C S T C S T Kera Basin Improvements 359 - 359 1,692 - 1,692 1,919 - 1,919 3,970 - 3,970 Urban Area Clearing Cleaning and Dredging Main Drains 139 - 139 - - - - 139 - 139 Local. Drains 282 - 282 217 - 217 221 - 221 720 - 720 Monitoring 38 58 96 9 20 29 5 16 21 52 94 146 Downstream Clearing, Cleaning and Dredging - - - 235 - 235 - - - 235 - 235 Channel Improvements Local Drains 344 - 344 422 - 422 347 - 347 1,113 - 1,113 Vehicles - 47 47 - 47 47 - 47 47 - 141 141

Total 1,162 105 1,267 2,575 67 2,642 2,492 63 2,555 6,229 235 6,464

C = Civil Works; S = Equipment and Materials; T = Total 9.6.2 Operations and Maintenance Costs

Operations and maintenance cost for the proposed drainage system, based upon projected 1985 requirements are summarized in Table 9.12 in 1980 prices). The costs exclude labor, equipment and materials used in capital programs.

TABI,E 9.12

ANNUAL OPERATIONS AND MAINTENANCE COSTS - 1985

Amount Item Thousands of Rupiah

1. Salaries and wages 65,000 2. Fringe Benefits 22,000 3. Honoraria etc. 9,000 4. Vehicle 0 & M 46,000 5. Small Tools and Supplies 3,000 Total 145,000 Less existing system 61,000 Incremental costs 84,000

9.6.3 Implementation Schedule

The recommended implementation schedule for the proposed drainage system improvements is shown in Figure 9.12.

9-49 "-I a, m DRAINAGE IMPLEMENTATION SCHEDULE

STAGE I ITEM REPELITA III 1979/80 1980/81 1981/82 1982/83 1983/84

LONG TERM PROGRAM PREUMINARY PLANNING

FEASIBILTY STUDIES - PROJECT APPRAISAL AGENCY BANK NEGOTIATIONS - RIdQUEST PROPOSALS - SELECT CONSULTANTS MOBILIZE DESIGN TENDERS -

KERA BASIN IMPROVEMENTS URBAN AREA CLEARING CLEANING DREDGMN m - LOCAL DRAINS - MAIN DRAINS - MAJOR RIVERS MONITORING 1 DOWNSTREAN CLEARING CLEANING DREDGING C3 CHANNEL IMPROVEMENTS- LOCAL DRAINS - MAIN DRAINS - MAJOR RIVERS Wi

C3 m-4 C3 SECTION 10

ECONOMIC AND FINANCIAL ANALYSIS OF FIRST STAGE PROG,AM

10.1 INTRODUCTION

In this section, financial and economic appraisal is undertaken of the investments proposed during 1980/81 - 1983/84. The financial pro jections cover the period 1980/81 through 1989/90 but do not allow for possible investments in Repelita IV. Because of the uncertainties of timing, extent and funding of such works no attempt has been made to an ticipate these in the projections.

As there is no satisfactory method for valuing the benefits associated with the project investments, the economic internal rate of return has not been calculated. Rather the potential benefits are discussed and evaluated in qualitative terms with no attempt at quantification.

10.2 PROJECT COSTS

10.2.1 Capital Costs

The recommended drainage costs are summarized in Table 10.1. A breakdown of these by year is given in Appendix B.

These costs are based on the engineering estimates contained in Section 9.6 and adjusted as follows:

" Physical contingencies at 15 percent of total capital costs and engineering supervision at 10 percent of costs excluding land have been incorporated into the estimates.

" Price contingencies (inflation allowances) have been added, based on estimates provided by the Asian Development Dank. These rates are:

1980 1981 1982 1983 1984 Local Currency 15% 15% 10% 10% 8% Foreign Exchange 8% 8% 7% 6% 6%

10-1 TABLE 10.1

DRAINAGE CAPITAL COSTS - FIRST STAGE PROGRAM Rp. in Millions

Foreign Item Direct Indirect Total Local Total

Land - - - 42 42

Civil Works 1539 2031 3570 2659 6229

Equipment and Materials 85 150 235 - 235

Engineering and Construction Supervision 323 - 323 323 646

Sub-total 1947 2181 4128 3024 7152

Physical Contingencies 291 327 618 453 1071

Sub-total 2238 2508 4746 3477 8223

Price Contingencies 494 573 1067 1397 2464

Total 2732 3081 5813 4874 10687

10-2 iA 10.2.2 Foreign Exchange Costs

Out of the total cost of Rp.10,687 million, 46% is in foreign exchange. This is considered a maximum estimate. There is always a considerable degree of uncertainty when estimating foreign exchange requirements as the allocation of supply and civil ontracts between foreign and local companies cannot be predicted with certainty. The foreign exchange estimates assume that when construction and supply contracts are considered likely to attract international bids, the latter would be successful.

Other assumptions used in estimating foreign exchange costs are:

" The classification of a foreign exchange cost as either direct or indirect has been made on the basis of whether payment is made in local or foreign currency by the project. If payment is made in local currency the cost is classified as indirect. For instance, Indonesia is a net importer of cement and is likely to remain so during the project construction period. Cement is therefore considered a foreign exchange cost but as it will be purchased by the project in rupiah it is classified as indirect.

* In cases when materials and equipment are imported direct to the project, c.i.f. prices have beea taken as the foreign exchange component. Customs duties, taxes and subsequent handling and transportation charges are local costs.

* Foreign contractors profits and overheads have been taken as 20 percent, with a 5 percent allowance for depreciation on imported plant. These are treated as direct foreign exchange costs.

10.2.3 Operation and Maintenance Costs

Operation and maintenance costs as discussed in Section 9 have been incorporated into the analyses.

10.3 PROJECT FUNDING

10.3.1 General Approach to Funding MUDS Programs

In discussions with G01 officials, it was emphasized that priority should be given to obtaining funds from local governments for investment in the sanitation programs proposed as part of the MUDS investments. To determine the ability of Kotamadya Medan to contribute to the program a detailed analysis was undertaken of the municipality's financial resources, existing and potential. Full details of this analysis are contained in Section 21 of the Long Term Urban Development Plan report (Volume III). The conclusion reached was that, while considerable potential exists for improving municipal receipts, this requires a major change in financial practices and controls, particularly in respect of tax assessments, collections and budgetary procedures. Technical assistance has been

10-3 ( recommended to assist the municipality in effecting these changes but full benefits will only materialise over a period of years. Until these im provements in fiscal and accounting practices are achieved, the munici pality's financial position will remain, as at present, extremely con strained.

Even on the assumption that tax receipts can be improved during Repelita III, only a very limited contribution from the Kotamadya's own resources will be available for investment in the MUDS programs. This reflects both the size of the investments required and the demand for increased funds to renovate and maintain existing urban facilities which have been seriously neglected in recent years.

In Table 10.2, the Kotamadya's own financial resources available for development expenditure are shown. The assumptions used in making this projection are given in detail in Section 21 of Volume III. Table 10.2 also shows how these resources have been allocated to the MUDS sectoral programs.

The trend of the surplus in constant prices during Repelita III declines, despite the assumption that revenues will start to increase during this period as a result of improved revenue and budgetary procedures. This is because of the need to give priority to improving the level of maintenance on existing facilities.

Approximately 85% of the surplus availa~le in the Repelita III period is allocated to the MUDS programs; this means that very few local funds will be available for non-MUDS expenditures. In the circumstances this is acceptable as the MUDS program covers the priority sectors. It should also be noted that in 1978/79 external funds accounted for just under 40% of development investment in Medan, external. funds can similarly be expected to be available in future for other developments in Medan. Only in the case of the KIP and solid wastes programs has pert of the surplus been allocated to front-end capital investment in Repelita III. In the other sectors the surplus has been allocated to 'cash' operating and working capital requirements as necessary. It would be possible,of course, to reduce the 'own' capital investment in KIP and solid wastes and spread it evenly among the other sectors. This however would simply mean that the KIP and solid wastes loan/grant requirements would increase by the corresponding amount. Giving priority to KIP and solid wastes for municipal investment contribution reflects current GO requirements.

Because of the limited 'own' funds available from the Kotamadya during Repelita III, the municipality will be required to obtain loan and grant finance from GO for the balance of the funds. It is possible that such finance would be channeled through the provincial government but it is unlikely that the provincial government would be in position to provide these funds from its own resources. The mix of loan/grant finance has been based on discussions with GO officials and the ability of the Kotamadya to handle future debt service payments. As can be seen from Table 10.2, the latter does not present a problem under the loan terms assumed (these are discussed separately under the financial assumptions in each of the appropriate sanitation reports).

10-4 TABLE 10.2

PROJECTION OF KOTAMADYA MEDAN'S CONTRIBUTION TO MUDS PROGRAMS Rp. in Millions

1981/82 1982/83 1983/84 1984/85 1985/86 1986/87 1987/88 1988/89

Current account surplus Constant 1978 prices a) 762 651 512 754 944 1284 1563 1882 Current prices b) 1189 1107 957 1538 2067 3005 3923 5044 Allocation to MUDS programs 1. Wastewater Cash operating costs - 56 121 533 573 615 657 704 Debt service - - - - - 282 282 282 2. Drainage C Cash operating costs 85 160 191 225 260 277 297 318 !t Debt service ..... 585 585 585

3. Solid wastes 'Own'capital investment 300 300 200 ..- -. Working capital 350 150 -..... Debt service c) - - -... 4. KIP d) 'Own' capital investment 200 350 300 - - - -

Total allocated 935 1016 812 758 833 1759 1821 1889

Notes: a) Source: Table 21.9, Section 21, Volume III b) Converted to current prices using local inflation factors provided by ADB (see 10.2.1) c) Solid wastes debt service and operating costs will be paid from solid waste revenue generation. The cash surplus resulting from solid waste operations has not been added back into the resources available for investment as this will be.required for vehicle replacement and expansion of solid wastes service coverage d) Some operating costs will be necessary for KIP but these will come substantially from sectoral programs A further consideration in respect of debt service is the GOl guideline that this should not exceed 20% of the development expenditure. If the latter is assumed to be the total of own (municipal) and external development expenditure, the maximum which MUDS debt service represents of this is 18% in 1986/87. In making this calculation debt service for solid wastes has been excluded as both operating costs and debt service payments for this service will be met directly from operating revenues (user chargers). If the solid wastes debt service is included, total debt service increases by almost 50% and the percentage of debt service to development expenditure becomes 27% in 1986/87. However, this reduces to 22% in 1987/88 and 18% in 1988/89. So even on this 'maximum' debt service assumption, only in two years is the guideline exceeded.

1986/87 1987/88 1988/89

Development expenditure (Rp m)* Own 2113 2969 4022

External ' 2595 2784 2972 Total 4708 5753 6994 Debt Service (Rp m)** 867 867 867 Debt Service % 18 15 12

It should be emphasized again that the ability of the Kotamadya to meet even the limited investment contribution, operating cost and debt service charges proposed is dependent upon the progressive adoption of improved revenue and taxation practices and generally improved financial housekeeping. The immediate implementation of a program such as that recommended in Section 21 and Appendix A of Volume III is an essential requirement if the Kotamadya is to meet the financial commitments proposed.

10.3.2 Drainage Funding

In view of the priority given to KIP and the solid waste programs for municipal investment funds, no contribution to front-end investment has been allowed for by Kotamadya Medan in the case of drainage. Funding is therefore assumed to be a mixture of loan and grant finance with the proportion of loan finance being determined by the ability of the Kotamadya to handle the debt service commitment involved. Based on the loan terms and conditions provided by GO1 officials (see 10.4.2.2) 50% loan finance was considered the realistic maximum. As discussed in 10.3.1, this level of debt service is repayable after taking account of other MUDS program commitments.

* Own development expenditure has been determined by deducting the cash operating costs for the MUDS sanitation and KIP programs (excluding solid wastes) from the current price surplus (see Table 10.2). External development expenditure has been calculated by assuming that the 1978/79 level will remain constant throughout. This has been converted to current prices using the ADB local inflation factors. ** Debt service excludes that for solid wastes.

10-6 The balancing 50% of the financing has been assumed as GO grant. If this level of funding (Rp. 5.3 million in Repelita III) is not forthcoming from the central or provi~rrial governments, a reduction in the size of the program would need to be considered. The alternative of in creasing the proportion of loan finance to this non-revenue generating sector beyond 50% would be dangerous. This proportion could possibly be increased if loan terms were eased still further, for example, very low interest or interest free. Such possibilities will need to be evaluated if grant financing on the scale required is not available and if the size of the proposed investment program is not to be seriously curtailed.

10.4 FINANCIAL EVALUATION

10.4.1 Introduction

Financial projections for the period 1980/81 - 1989/90 have been prepared. These are based on the capital expenditure and operating and maintenance costs associated with new and existing investments. The financial statements income, flow of funds and balance sheet - are shown in Tables 10.3 through 10.5. All financial calculations are in current prices, based upon inflation assumptions for local and foreign costs provided by the Asian Development Bank (1980 to 1984 - see 10.2.1) and a composite rate of 7% from 1985 onwards.

10.4.2 Financial Assumptions

10.4.2.1 Income Statement

The level of revenue has been fixed to cover operating costs plus depreciation or debt service - whichever is the greater. As reviewed in 10.3.1, such a level of income would be available from municipal resources on the assumption of improved financial performance by Kotamadya Medan. As discussed in 8.3, drainage service costs are more suitably recovered from general municipal income than specific drainage charges.

Depreciation has been calculated on annually revalued fixed assets on a straight line basis. The following depreciation rates have been adopted.

Type of Asset Annual Rate %

Drains 2 Vehicles 20 Monitoring Equipment 10

10.4.2.2 Balance Sheet and Flow of Funds

Fixed Assets

Fixed assets have been revalued annually in line with the inflation asssumptions discussed above. Depreciation includes an allowance for backlog depreciation; an equivalent amount has been added to the revalu ation surplus. 10-7 Lj TABLE 10.3

DRAINAGE - PROJECTED INCOME STATEMENT Rp. Million in Current Prices

1981/82 1982/83 1983/84 1984/85 1985/86 1986/87 1987/88 1988/89 1989/90

Revenue 85 229 375 538 595 862 882 903 925

Operating Expenses 85 160 191 225 260 277 297 318 340 0 6 Depreciation - 69 184 313 335 358 383 410 438

Total expenses 85 229 375 538 595 635 680 728 778 Income before interest - - - - 227 202 175 147 Interest ..... 481 472 461 450 Net surplus/(defecit) ..... (254) (270) (286) (303) TABLE 10.4

DRAINAGE - PROJECTED FLOW OF FUNDS STATEMENT Rp. Million in Current Prices

1981/82 1982/83 1983/84 1984/85 1985/85 1986/87 1987/88 1988/89 1989/90

Source of Funds Income before depreciation - 69 184 313 335 585 585 585 585 GUI loan 967 2146 2231 ------GOI grant 968 2145 2230 ------Total Sources 1935 4360 4645 313 335 585 585 585 585

Application of Funds Project investment 1935 4291 4461 ------Increase/decrease in working capital* ------Loan interest ..... 481 472 461 450 Loan amortisation - -... 104 113 124 135 Total Applications 1935 4291 4461 - - 585 585 585 585

Net cash generated - 69 184 313 335 - - - - Opening cash balance - 69 253 566 901 901 901 901 Closing cash balance 69 253 566 901 901 901 901 901

* Excluding cash TABLE 10.5

DRAINAGE - PROJECTED BALANCE SHEET Rp.Million in Current Prices

1981/82 1982/83 1983/84 1984/85 1985/86 1986/87 1987/88 1988/89 1989/90

Assets Fixed assets 40 2116 6904 12280 13139 14055 15045 16092 17221 Less depreciation - 69 258 592 968 1394 1875 2416 3023 Net fixed assets 40 2047 6646 11688 12171 12661 13170 13676 14198 Work in progress 1895 4290 4460 - - - - - Inventories 201 442 462 19 21 23 25 26 28 Cash - 69 253 566 901 901 901 901 901 Total current assets 201 511 715 585 922 924 926 927 929 Total assets 2136 6848 11821 12273 13093 13585 14096 14603 15127 Equity & Liabilities Revaluation surplus - 180 672 1567 2385 3233 4125 5041 6001 Equity 968 3113 5343 5343 5343 5343 5343 5343 5343 Operational surplus - - - - - (254) (524) (810) (1113) Total Equity 968 3293 6015 6910 7728 8322 8944 9574 10231 Long term debt (net) 967 3113 5344 5344 5240 5127 5003 4868 4721 Accounts payable 201 442 462 19 21 23 25 26 28 Current maturities - - - - 104 113 124 135 147 Total current liabilities 201 442 462 19 125 136 149 161 175 Total equity/liabilities 2136 6848 11821 12273 13093 13585 14096 14603 15127

Current ratio - 1.16 1.55 30.79 % Debt/(Debt + Equity) 50.00 48.60 47.05 43.61 Capital expenditure is shown as work in progress in the year of asset acquisition and transferred to fixed assets in the following year, from which time depreciation commences. This is realistic in view of the nature of the capital works.

Working Capital

Inventories are taken as 10 percent of current year capital expenditure and25 percent of annual expenditure on materials.

Accounts payable are estimated at 10 percent of current year capital expenditure and one month's cash operating expenses.

Cash is calculated as a residual figure on the sources and appli cation of funds statement. The cash surplus shown during Repelita IV would not materialize. The surplus results from depreciation provisions at a time when no allowance has been made for continuing capital expenditure. It would, in practice, be used for second stage investments. No interest income has been provided for on what is, in effect, a nominal cash surplus.

Loan Terms

The funding mix has been discussed in 10.3.2. The terms on which the 50 percent loan finance (Rp. 5344 million) would be provided is as follows:

" Loan repayment over 25 years, including a 5 year grace period

" Interest rate at 9 percent p.a. - waived during construction

" Repayment by way of a flat rate annuity of Rp. 282 million, commencing 1986/87

Financing Plan

The financing plan for 1980/81-1983/84 which derives from the source and application of funds statement is shown below:

SUMMARY OF FINANCING PLAN 1981/82-1983/84 Rp. million US $ million Application of Funds Project Cost 10687 17.10 97.7 Working Capital 253 0.40 2.3 Total 10940 17.50 100.0

Source of Funds GOI Loan 5344 8.55 48.9 GOI Grant 5343 8.55 48.9 Internal Cash Generation 253 0.40 2.2 Total 10940 17.50 100.0

10-11 It is anticipated that, at minimum, the foreign exchange element of project costs would be lent to GOI by ADB. Thir represents Rp. 4.9 million of investment costs and would be on-lent by GOI to the pro.ect as part of its loan/grant funding.

10.4.3 Financial Evaluation

The critical considerations in reviewing the projected financial performance of drainage operatio:.s are:

1. Whether the required revenue will be available from the municipality's resources and

2. Whether the assumed funding conditions are realistic.

The attainment of the revenue requirement has already been discussed (10.3) and would seem feasible. The funding basis is more uncertain. Because of the size of the drainage program the grant require ment from GOI is substantial. It has been suggested recently by GOI officials that this exceeds what can be made available. As discussed in 10.3.2, this would probably lead to a reduction in program size or a larger loan with easier debt servicing, although the scope for the latter is likely to be limited. What the analysis here indicates is that a loan of Rp. 5.3 million on the terms assumed is repayable by the Kotamadya; to the extent that this can be matched by grant finance, the program objectives will correspondingly be attained.

10.5 ECONOMIC EVALUATION

10.5.1 Introduction

The recommended improvements in the drainage system have been described in Section 9. Essentially these works provide for new drains in areas where flooding problems are critical and the clearing, cleaning and dredging of existing channels to maximize their flood control potential. Once channels have been cleared, flood flows will be monitored to provide a basis for the detailed planning of future major drainage works.

10.5.2 Benefits of Proposed Investments

10.5.2.1 Flood Control

A reduction in the incidence of flooding has the benefits of less disruption and incovenience to commercial and private life and less damage to property. The proposed investments will be undertaken in areas where such benefits will be maximized. No statistics exist on the extent of flood damage or on the frequency of flooding, and the usual problem of quantifying potential benefits is faced. But flood damage to property and roads is a predictable recurring event.

In addition to the property damage itself, floods cause chaos on the roads and disrupt commercial activity. This clearly has a cost. Also, the personal suffering and incovenience is considerable. Surveys

10-12 undertaken by the project team in the kampungs received very strong comments on the appaling state of the drains; of all the activities proposed under the MUDS project, improvements to the drains was given the highest priority.

10.5.2.2 Health Benefits

There are likely to be some health benefits resulting from the drainage investments, but less macked than in the case of the other sanitary programs. The ponding which is a notable feature of the system at present is ideal for mosquito breeding but the incidence of malaria in Medan city is reported to be low, so not too much emphasis should be laid on potential health benefits.

10.5.2.3 Environmental Benefits

Many of the drains are extremely unslightly; they harbour wastes of all types which are strewn over roads and into private property when heavy rains occur. Any worthwhile improvement in the quality of the urban environment in Medan necessitates action to ameliorate this situation. Other investments proposed will not achieve their full potential in improving the environment if the drains are not also improved as part of a concerted program.

10.5.2.4 Capital Preservation

An argument which can be used (and often valued) when making in vestments to preserve existing facilities is that the deterioration in these facilities which would have occurred in the absence of the project is prevented. This argument is at its strongest when the facilities to be preserved are in good condition and when there are strong grounds for assuming that, in the absence of the proposed project, action would not be taken to adequately maintain them. When the facilities are already in poor condition the potential for savings in lost value is more restricted. No doubt, despite their poor condition, Medan's drainage assets are very real (if unquantifiable) and the levels of expenditure for preserving them quite inadequate. The proposed program will certainly have the very tangible benefit of limiting this deterioration and loss in value.

10.5.3 Summary

No attempt has been made at calculating the economic or financial internal rates of return. This would be a spurious exercise. As already argued, drainage is an essential urban amenity, particularly in a large city like Medan with poor natural drainage and a susceptibility to flooding. The need has been recognized in the past as lined and unlined drains have been installed throughout the city. The proposed investment would pre serve, rejuvenate and make effective again this system.

11 APPENDIX A

EXISTING DRAINAGE SYSTEM

APPENDIX A-i Major Channel Cross- Sections

APPENDIX A-2 Estimated Capacity of Main Channels APPENDIX A-i

MAJOR CHANNEL CROSS-SECTIONS

A-i NO I SCALE I 2M

NO 2 SCALK 1 200

._.*LL . ._ , -o . ... L ...-. - . .£ 1 . . ..pe,....

NO 3 SCALEI 200

______491

0 g -- so so -- '" a 0 ....- ,-@ -- t---. ... - ._JQ. -.- .6 0 Q ; 0

NO. 4 SCALE I 200

Bet Available Document

PADCO-DACREA FIGURE A.I

EXISTING MAIN CHANNEL CROSS SECTION

4601, - - ' . _ - o o.t --- .0----- t .. .

NO. 5 SCALE I 2O

NOTE IN METRES S- - t- "-_ __ . ALL DWENSIONSARE EXCEPT OTHERWAIUNOTED

NO. 6 SCALE I 200

4 __o60__...... ,, . . _ -. 2.. _1. A2o oo

NO. T SCALE I 200

-- -- -- --

i 0 60 1010 ._ a00 5 5o

t 5 o

SCALEI 00 NQ 8

SCALI I O

Documenlk Best Available

ENGINEERING-SCIENCE SINOTECH +- 40 4.

NO.9 SCA.L I 200

,1o , 43 so 40

NO. 10 ICM.! I EDO

go 1 12 . 4 o 4 IAo-... 30

------NO. 11 SCALE1 200

44t2

420 o0 20 tl o t t2o 02o2204 o . f to 10- a 0El 20 to

NO. 12 scN.9 I 2O0

PADCO4ACREA FIGURE A.2

EXISTING MAIN CHANNEL CROSS - SECTION

.. , . 0 0 40 40 70 t0

NO13 SCA.E I 200

*0 71...... I 4 .5 " -" II I 0 6 0 3

-- 4 t4rf1ti t't+L , NOTE ALL OIMENSIONSARE IN METRES

- EXCEPT OTHERWISE NOTED.

NO. 13' SCAL! I t0 4 4

. tL L 20o 4. 1o 0 4 j 1-0 . _0. 4 oIl Q_ t 9 9,tL4- + . +

NO.14

NO.I1 200

SCALE 1 200

NO. 15 SCALEI 800

ENGINEERING-SCIENCE SINOTEC NO. 16 ICALI 1 OO

°i L O...C_ '

mA 8n o

1. . ...9 3 ......

ICML[I 00

NO. Is NO.--8 0 ______3 0014 2

,2 NO. ISo ,* i

NO. 19 ECALI I 00

PADCO-DACREA FIGURE A.3

EXISTING MAIN CHANNEL CROSS - SECTIONS

j4 0.40 ......

N020 NOTE; . . ... WAL 50 ."

- 30 ,o-ALL30 OUNSIONS ARE IN METRES to 11 EXCEPT OTHERWISENOTED.

000

NO.21

t 2 .2 0314 ItoSC~lly + - 0 94! 0

"1 N023

0 AL 10 100 NQ22 C . 1100I O

8 -0 08 1 Is a .5m ,CALI I 50

o 3 4 so

ICA" I too

NO.24 Cutl I goo SCl I I00

] jvalaleDocumsut es

ENGINEERING-SCIENCE - SINOTECH I I SALEI 1200 NO- 29 SCALI 1100

" ' ". a" t- 06 6 t ON" 20 ' 1 0 t- A" tgqff -

NO26

SCALE I 00 NO- 30 SCALE 1,100 4 ___-tO7 20i -4i ' "t-- " -"

121 0______NO 27 SCALE I 00

NO- 31

SCALE 1-100

NO 28 SCALE 0I0

nut 'BestBlvtailble Docu PADCO-DACREA \, FiGURE A.4

EXISTING MAIN CHANNEL CROSS - SECTIONS

NOTE ALL DIMENSIOS AREIN METRES EXCEPT OTHERWISE NOTED

. 9_t---- A. 0. t .. "__ -

M ~IS

NO- 32 SCALE 1100

SCALE 10100

S I aI 75 lOa NO.33 SCALE 1 200 SCALE 1-100

Best Available Documenl

ENGINEERING-SCIENCE SINOTECH 40 1S a51 *4 411 7j" 10 10 1 .. l le il "W-e *

NO.34 $CAL* I 100 '' ' ; ° _____"__" *-'I + S'"B

13 2 2 2 31

NO.35

+1- 1 0 -4--t 2--+ 1-0

0 9 20~~~~~ t 40 4~+j 10 07~5

NO.40 , I ,o io i , I ,o t I,o , i oft. t O. I SCAL I

NO.40 NO.36SCALE 1 I0

I SO NO.3N4 SSEALE

SCALE 1 50

PADCO-DACREA 17 FIGURE A.5

EXISTING MAIN CHANNEL CROSS - SECTIONS

110 0 10

NO.42 NO.38 CALE 1 100 SCA.I I 100

: IO..-NOTE. I*o o7 4i;j too.1-

ALL DOWdNSIONSARE IN METARS -- '- ~ EXCEPT OTHEOW5 NOTIO

N043 NO.46 VALK 100 SCALKI too

NO,39 SCALEI IOn

0 0 10 10 .0 5 3IS 20 0 0 0 10

NO.40 o t NO.44 SCALE1 $CL 1 100

100 34 1 0 10 10 Ito 30 a 0S

05 1 15 a Is. 1; -- 0 C~LINE~ CALEI:5O 8 LIS l ; I .4I 0 1 2 3 4 5.4 SrALIE 1 100 NO.45 NO.41 I s___ _ SCALE10 scALK1 00 _ _ 0 225 13? ION SCALEI 100

ENGINEERING-SCIENCE SINOTEC I1O • 0 ZOD ______41oso, 1012' 20 2,0 so 9 4&10-40l 40 eq" I I

NO.52 N053 AILI 100 SCA L I 00

NO. 47 SCAL I too

- 0 "-V **Il______

14 0

NO.48 NO.54 SCALE. a00 SCALEI 100

t4I w-PC c

NO.49 SCALE I I0o NO55 50 SCALE I so

ITS

4 V W PC'l4 10. 2

NQ50vO

100 SCALE1

41'

PCPC*0 O 5

80 0 0IIl

N057 SCA I. 00

PADCO-DACREA FIGURE A.6

EXISTING MAIN CHANNEL CROSS-SECTION

SCALl I 100 24f

14 to 20 20 -I-I 40 20 20 10 I 00 ; . 0 20 I 06 NOTE MNSIONS AREIN METRES ~ '~" S - ~ALL EXCEPT OTHERWISE NOTEO.

NO 59 SCALE I t00

01 12 0 A 0 JOjlO. 4 0 12 110 i 20 11 12 J

0 o

NO.60 SCALE I I00

240 4

1.2 6 .10. I ,20102 I # La i a

0 00 I I 2 22iS a ICAL I .S

0 Ii 2 4 Sm - SCAL9.I 100

0 2.1 G 75 we SCALE I 2002 NO.61 SCALE.I 100

Best Available Document

CUIUIU&Qp-IEUPE - ClUnTCI'U APPENDIX A-2

ESTIMATED CAPACITY OF MAIN CHANNELS

A-15 TABLE A-2.1

ESTIMATED CAPACITY OF EXISTING MAIN CHANNELS (WITH FREEBOAPJ))

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu m/s)

Deli River - Downstream (allow 0.6 m freeboard)

1 120 54.8 1 - 2 108 49.1 0.00038 0.035 102 2 96 43.4 2 - 3 124.5 49.2 0.00098 0.035 207 3 153 55 3 - 4 136 53.55 0.00294 0.035 292 4 119 52.1 4 - 5 120.25 49.75 0.00067 0.035 160 5 121.5 47.4 5 - 6 82 45.30 0.00146 0.035 133 6 42.5 43.' 6 - 7 56.2' 42.15 0.00066 0.035 50 7 70 41.1 7 - 8 122.15 43.6 0.00105 0.035 225 8 174.3 46.1 8 - 9 155.9 45.65 0.00169 0.035 415 9 137.5 45.2 9 - 10 125.75 42.73 0.00136 0.035 273 10 114 40.25 10 - 11 132 42.57 0.00071 0.035 215 11 150 44.9 11 - A 150 44.9 0.00093 0.035 292 A A - 12 117.5 45.3 0.00053 0.035 146 TABLE A-2.1-Continued

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq i.) (sq m) (m) (m) (cu m/s)

12 117.5 45.3 12 - 13 144.65 44.15 0.00125 0.035 322 13 171.8 43 13 - B 171.8 43 0.00132 0.035 449 B B 13' 220.5 48.4 0.00132 0.035 629 13' 220.5 48.4 13'- 14 216.7 45 0.00153 14 212.9 41.6 0.035 691 14 - C 212.9 ~C 41.6 0.00064 0.035 457

C - 15 198 39 0.00064 0.030 493 15 198 39 15 16 180.25 39.9 0.00064 0.030 415 16 162.5 40.8 16 - 17 132.75 34.85 0.00133 17 103 28.9 0.030 394 17 - 18 105.5 30.3 0.00357 0.030 483 18 108 31.7

C C - 19 24.25 12.1 0.00227 0.040 46 19 24.25 12.1 19 - D 24.25 12.1 0.00227 0.040 46 D D - 20 5.75 6.4 0.00227 0.035 7 20 5.75 6.4 TABLE A-2.1-Continued

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu m/s)

D D - 21 8.75 9.3 0.00192 0.040 9 21 8.75 9.3 21 - 22 14.93 11.5 0.00192 0.033 24 22 21.10 13.8 22 - 23 12.42 9.65 0.00119 0.033 15 23 3.75 5.5

B. Babura River (allow 0.6 m freeboard)

B - 24 141.2 35.5 0.00119 0.035 349 24 141.2 35.5 24 - 25 150.5 38.15 0.00119 0.035 370 25 159.8 40.8 25 - 26 184.9 41.15 0.00167 0.035 388 26 210 41.5 26 - 27 162.,5 38.55 0.00078 0.035 338 27 115 35.6 27 - 28 130 33.05 0-0192 0.028 507 28 145 30.5 28 - 29 166.75 34.00 0.00769 0.025 1,688 29 188.5 37.5 29 - E 188.5 37.5 0.00278 0.625 1,166 E E - 30 31.44 16.7 0.00260 0.025 98 30 31.4 16.7

E E - 31 34.42 16.3 0.0025 0.035 81 31 34.42 16.3 TABLE A-2.l-Continued

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu m/s)

A. Sikambing River (allow 0.6 m freeboard)

A 32 - 86.75 55.3 0.00078 0.035 94 32 86.75 55.3 32 - 33 54.63 34.7 0.00078 0.033 63 33 22.5 14.1 33 - 34 25.75 16.7 0.00076 0.033 29 34 29 19.3 34 - 35 26.50 16.45 0.0007L 0.035 29 35 24 13.6 35 36 - 29.50 16 0.00076 0.035 35 36 36 - 37 35 18.4 23.20 14.13 0.00167 0.035 38 37 11.4 9.85

F F - 38 13.8 10.1 0.00172 0.045 16 38 13.8 10.10

Putih River (allow 0.3 m freeboard)

39 17 11 39 - 40 16.1 10.90 0.00119 0.035 21 40 15.2 10.8 40 - 41 8.7 7.70 0.00119 0.033 10 41 2.2 4.6 41 - 42 4.75 6.4 0.00147 0.038 4 42 7.3 8.2 42 43 - 5.2 6.55 0.00357 0.048 6 43 3.1 4.9 TABLE A-2.1- Continued

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu m/s)

Kera River (allow 0.3 m freeboard)

44 21.2 13.1 44 - 45 18.95 18.65 0.00500 0.030 45 45 16.7 24.2 45 - 46 13.15 17.45 0.00052 0.033 8 46 9.6 1,-.7 46 - 47 26.1 14.20 0.00052 0.035 26 47 42.6 17.7 47 - 48 48.5 18.65 0.00179 0.030 129 48 54.4 19.6 48 - G 54.4 19.6 0.00179 0.020 227 G G - 49 4.5 6.7 0.00357 0.020 10 49 4.5 6.7 49 - 50 4.15 6.25 0.00172 0.025 5 50 3.8 5.8 50 - 51 4.46 5.95 0.00208 6 51 5.12 6.1

52 5.6 6.3 52 - 53 5.8 6.35 0.00263 0.033 8 53 6 6.4

G G - 54 8 7.4 0.0056 0.020 32 54 8 7.4 TABLE A-2.1-Continued.

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m)) (cu m/s)

55 1.85 3.7 55 - 58 45.18 14.50 0.00160 0.025 58 88.5 25.3 154

Percut River (allow 0.6 m freeboard)

56 67.2 23 56 - 57 63.6 23.50 0.00143 0.028 57 60 24 169 57 - 58 74.25 24.65 0.00069 58 88.5 25.3 0.028 145 58 - 59 102.25 27.55 0.00069 0.030 215 59 116 29.8 59 - 60 122 30.7 0.00303 0.030 562 60 128 31.6 61 61 - 176 37 0. 00104 0 .035 459 TABLE A-2.2

ESTIMATED CAPACITY OF EXISTING MAIN CHANNELS (WITHOUT FREEBOARD)

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (,-u mis)

Deli River - Downstream

1 136 57.7 1 - 2 122.05 49.85 0.00038 0.035 124 2 "108.10 44 2 - 3 136.05 49.75 0.00098 0.035 238 3 164 55.5 3 4 150 - 54.15 0.00294 0.035 459 4 136 52.8 4 - 5 142 50.8 0.00067 0.035 209 5 148 48.8 5 6 107.75 46.7 0.00146 0.035 206 6 67.5 44.6 6 7 80.55 43.5 0.00066 0.035 89 7 93.6 42.4 7 8 145.8 44.95 0.00105 0.035 296 8 198 47.5 8 9 180.25 47.15 0.00169 0.035 518 9 162.5 46.8 9 - 10 149.25 44.28 0.00136 0.035 354 10 136 41.75 10 - 11 154.95 44 0.00071 0.035 273 11 173.9 46.2 11 - A 173.9 46.2 0.00093 0.035 367 A A - 12 143 47.7 0.00053 0.035 196 12 143 47.7 12 - 13 165.5 46.05 0.00125 0.035 392 TABLE A-2.2 - Continued

Section River Sectfon Average Section Average Number Reach Average Estimated Estimated Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu m/s) 13 188 44.4 13 - B 188 44.4 0.00132 0.035 511 B 13' 245.7 49.8 0.00132 13 ' 245.7 49.8 0.035 739 13'-14 238.35 46.4 0.00153 14 231 43 0.035 794 14 - C 231 43 0.00064 0.035 512 C 15 216 40.3 0.00064 15 0.030 558 216 40.3 15 - 16 200.65 41.2 0.00064 0.030 486 16 185.3 16 - 17 42.1 150.15 36.75 17 115 31.4 0.00133 0.030 467 17 - 18 119.9 32.25 0.00357 18 0.030 573 124.8 33.1

1 C 19 27.25 13.3 19 27.25 13.3 0.00227 0.040 52 19 - D 27.25 13.3 0.00227 0.040 52 D - 20 7 7.1 0.00227 20 7 7 .1 0.035 9

D D 21 11.15 9.9 0.00192 0.040 13 TABLE A-2.2-Continued

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu m/s)

21 11.15 9.9 21 - 22 17.78 12.20 0.00192 0.033 30 22 24.40 14.50 22 - 23 14.81 10.35 0.00119 0.033 20 23 5.22 6.2

B. BaburaRiver (Tributary of Deli River)

B - 24 158.6 36.7 0.00119 0.035 415 24 158.6 36.7 24 - 25 170.3 39.6 0.00119 0.035 444 .25 182 42.5 25 - 26 207.4 42.85 0.00167 0.035 693 26 232.8 43.2 26 - 27 1S4.25 41.4 0.00078 0.035 398 27 135.7 39.6 27 - 28 149.8 38.8 0.00192 0.028 577 28 163.9 38 28 - 29 185.5 38.65 0.00769 0.025 1,852 29 207.1 39.3 29 - ,: 207.1 39.3 0.00278 0.025 1,323 E E 30 37.74 18.2 0.00260 0.025 125 30 37.74 18.2

E E - 31 44.66 18.4 0.0025 0.035 115 31 44.66 18.4 TABLE A-2.2--Continued

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slop Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu m/s)

A. Sikambing River

A - 32 101.75 56.8 0.00078 0.035 120 32 101.75 56.8 32 - 33 64.33 35.95 0.00078 0.033 80 33 26.9 15.1 33 - 34 29.7 17.5 0.00076 0.033 35 34 32.5 19.9 34 - 35 30.25 17.1 0.00076 0.035 35 35 28 14.3 35 36 33.75 16.65 0.00076 0.035 43 36 39.5 19 36 - 37 26.55 14.78 0.00167 0.035 46 37 13.6 10.55

F F 38 16.35 10.90 0.00172 0.045 20 38 16.35 10.90

Putih River

39 19.5 12 39 - 40 18.6 12.2 0.00119 0.035 24 40 17.6 12.4 40 - 41 10.4 8.8 0.00119 0.033 12 41 3.2 5.2 41 - 42 6.3 7.25 0.00147 0.038 6 42 9.4 9.3 42 - 43 7.15 7.6 0.00357 0.048 9 43 4.9 5.9 TABLE A-2.2-Continued

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu m/s)

Kera River

44 24.2 13.9 44 - 45 21.95 19.45 0.00500 0.030 56 45 19.7 25 45 - 46 16.15 18.25 0.00052 0.033 10 46 12.6 11.5 46 - 47 29.55 15.0 0.00052 0.035 30 47 46.5 18.5 47 - 48 52.50 19.55 0.00179 0.030 143 48 58.5 20.6 48 - G 58.50 20.6 0.00179 0.020 248 G G - 49 5.80 7.3 0.00357 0.020 15 49 5.8 7.3 49 - 50 5.55 6.90 0.00172 0.025 8 50 5.3 6.5 50 51 5.90 6.65 0.00208 0.028 9 51 6.5 6.8

52 6.9 7.1 52 - 53 6.45 7.05 0.00263 0.033 9 53 6 7

G G 54 9.68 8.2 0.0056 0.020 40 54 9.68 8.2

55 2.57 4.35 55 - 58 51.39 16.08 0.00160 0.025 178 58 100.20 27.8 TABLE A-2.2-Continued

Section River Section Average Section Average Average Estimated Estimated Number Reach Area Area Perimeter Perimeter Slope Manning 'n' Capacity (sq m) (sq m) (m) (m) (cu mis)

Percut River

56 77.76 24.2 56 - 57 74.73 25.85 0.00143 0.028 205 57 71.7 27.5 57 - 58 86.1 27.6 0.00069 0.028 173 58 100.5 27.7 58 - 59 115.45 29.4 0.00069 0.030 252 59 130.4 31.1 59 - 60 136.85 32.2 0.00303 0.030 659 60 143.3 33.3

61 61 - 200 39 0.00104 0.035 548 APPENDIX B

DRAINAGE CAPITAL COSTS: 1981/82 - 1983/84 DRAINAGE CAPITAL COSTS: 1981/82 - 1983/84 RP IN MILLIONS

1981/82

Foreign Item Direct Indirect Total Local Total

Land acquisition - - - 40 40 Civil works 278 278 556 606 1162 Equipment & Materials 55 50 105 - 105 Engineering & Construction Supervision 63 - 63 63 126 1433 Sub-total 396 328 724 709 Physical contingencies 59 49 108 106 214 Sub-total 455 377 832 815 1647 Price contingencies 56 46 102 186 288

Total 511 423 934 1001 1935

1982/83

Foreign Item Direct Indirect Total Local Total

Land acquisition - - - 1 1 Civil works 640 848 1488 1087 2575 Equipment & Materials 17 50 67 - 67 Engineering & Construction Supervision 132 - 132 132 264 Sub-total 789 898 1687 1220 2907 Physical Contingencies 118 135 253 183 436 Sub-total 907 1033 1940 1403 3343 Price contingencies 188 214 402 546 948

Total 1095 1247 2342 1949 4291

B-i 1983/84

Foreign Local Total Item Direct Indirect Total

- 40 40 Land acquisition _ - 606 1162 Civil works 278 278 556 - 105 Equipment & Materials 55 50 105 Engineering & Construction Supervision 63 - 63 63 126 1433 Sub-total 396 328 724 709 106 214 Physical contingencies 59 49 108 1647 Sub-total 455 377 832 815 186 288 Price Contingencies 56 46 102

1935 Total 511 423 934 1001

B-2