chapter three emerging practices of international investment arbitration tribunals in adjudicating

92 Pages·2017·2.67 MB·English

ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES
ADDIS ABABA INSTITUTE OF TECHNOLOGY (AAiT)
DEVELOPMENT OF A MODEL FOR ESTIMATING NON REVENUE
WATER IN ADDIS ABABA

(THE CASE OF BOLE SUB CITY)

A Thesis Submitted to the School of Graduate Studies of Addis Ababa University in
partial Fulfillment of the Requirement for the Degree of Master Science in Hydraulic
Engineering

By: Ephrem Mengistu
Advisor: Dr. Mebrate Tafesse
October, 2016
DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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ABSTRACT
One of the major bottleneck for the water utilities is a large number of water losses in the
distribution network system and quantifying of this water loss. This is why this thesis focuses
on the development of a model for estimating Non Revenue Water (NRW) in Addis Ababa,
especially woreda-07 in the Bole sub city.
The method used for the model starts with component of real loss by applying Minimum Night
Flow (MNF) data taken at a particular installed District Metered Area (DMA). Analysis of the
network system is based on the background leakage and concept of Fixed and Variable Area
Discharge (FAVAD) in addition with aggregated bill consumption of the study area.
Bentley Water GEMS hydraulic model is prepared to apply the procedure. Then, calculating
network leakage at the minimum hour flow (MNF) and distribution of volumetric consumption
at each junction for each time step is carried out. In doing so, for leakage plus volumetric, the
model runs until the probable pressure and leakage coefficient is established.
Using the coefficient in regard with the demand factor for each hour, leakage at each node and
pipes for the distribution network is estimated. Based on these information estimated value of
real loss 21.04%, apparent loss 4.74 and NRW 131,522.2 m3/year with 25.8% is found.
Finally, for a more representation of the network and to perform further analysis regarding of
water losses a suitable model environment is created in Arc GIS environment; which can be
used as an aid around the study area.
Key words: water supply network, water loss, leakage, real loss, apparent loss, MNF, NRW,
Water GEMS, pressure.

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DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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ACKNOWLEDGMENTS
Above all I would like to thank GOD who give me health, unleashed the hard times and to
carry out this work.
I would like to thank my families especially to my mother Truwork for her love, care and
helping me starting from my childhood.
I am very grateful to express my sincere thanks to my advisor, Dr. Mebrate Tafesse for his
guidance, encouragement and support.
I would also like to express my gratitude to the staffs of Addis Ababa Water and Sewerage
Authority (AAWSA) and my special regards for Ato Teklu, NRW expert of the AAWSA - for
his kindness and given me the necessary data, meetings and thoughts.
I must also thank ERA sponsorship program for giving me this chance.
Finally, I would like to thank all of my colleges and friends for their supportive materials and
kindness.
.

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DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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TABLE OF CONTENTS
ABSTRACT .......................................................................................................................................... I
ACKNOWLEDGMENTS ...................................................................................................................... II
TABLE OF CONTENTS ..................................................................................................................... III
LIST OF FIGURES ............................................................................................................................ VII
LIST OF TABLES ............................................................................................................................. VIII
APPENDICES .................................................................................................................................... IX
LIST OF ACRONYMS ......................................................................................................................... X
1. Introduction 1
1.1 Background ................................................................................................................................... 1
1.2 Addis Ababa water supply and distribution system ...................................................................... 2
1.2.1 Surface water sources ............................................................................................................... 2
1.2.2 Ground water sources ................................................................................................................ 2
1.2.3 Water supply network................................................................................................................. 3
1.2.4 Water tariff/price ......................................................................................................................... 3
1.3 Description of the study area ........................................................................................................ 3
1.4 Rationale of the Study ................................................................................................................... 7
1.4.1 Water demand and its pattern .................................................................................................... 7
1.4.2 NRW of Addis Ababa ................................................................................................................. 7
1.4.3 Practice of estimating NRW ....................................................................................................... 8
1.4.4 Challenges for determining amount of NRW ............................................................................. 8
1.4.5 Shortage of potable water supply .............................................................................................. 8
1.5 Statement of the problem .............................................................................................................. 9
1.6 The Research objectives .............................................................................................................. 9
1.6.1 General objectives ..................................................................................................................... 9
1.6.2 Specific objectives ...................................................................................................................... 9
1.7 Overview of the thesis ................................................................................................................. 10
2. Literature Review 11
2.1 Introduction ................................................................................................................................. 11
2.2 Components and definitions of Non Revenue Water .................................................................. 11
2.3 Apparent losses .......................................................................................................................... 12
2.3.1 Authorized consumption .......................................................................................................... 13

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DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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2.3.2 Unbilled authorized consumption ............................................................................................. 13
2.4 Real or Physical losses ............................................................................................................... 14
2.4.1. Leakage in the distribution system .......................................................................................... 16
2.4.2. Pressure in the distribution system ......................................................................................... 16
2.4.3. Water distribution pipes and materials .................................................................................... 17
2.4.4. Purpose of Minimum Night Flow analysis ............................................................................... 18
2.5 Performance indicators for water losses ..................................................................................... 19
2.5.1. Performance indicators for real loss ....................................................................................... 20
2.5.2 Performance indicators for apparent loss ................................................................................ 21
2.6 Modeling practices and use for NRW ......................................................................................... 21
2.6.1 Modeling practices ................................................................................................................... 21
2.6.2 Use of modeling application ..................................................................................................... 22
2.6.3 Bentley Water CAD application ................................................................................................ 23
2.6.4 GIS application ......................................................................................................................... 23
2.6.5 Comparison of modeling software ........................................................................................... 24
2.6.6 Integration of models and between software’s ........................................................................ 24
2.7 Aspects for water losses ............................................................................................................. 25
2.8 Consequence of NRW ................................................................................................................ 26
2.8.1 Potable water scarcity / shortage ............................................................................................. 26
2.9 Leakage management and monitoring ....................................................................................... 27
2.9.1 Basic concepts of leakage management and monitoring ........................................................ 28
2.9.2 Miscarrying of NRW management and monitoring .................................................................. 30
2.9.3 Purpose of estimating NRW ..................................................................................................... 30
2.10 Theoretical Background ............................................................................................................ 31
2.10.1 Minimum night flow (MNF) ..................................................................................................... 31
2.10.2 Daily real loss volume ............................................................................................................ 31
2.10.3 Pressure and leakage relationship ......................................................................................... 32
2.10.4 Computer modeling ................................................................................................................ 32
2.10.5 Leakage assessment methods .............................................................................................. 32
2.10.6 Assumptions in leakage estimation ........................................................................................ 33
3. Methodology 35
3.1 Process of study area selection .................................................................................................. 35
3.2 Selected study area .................................................................................................................... 35

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DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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3.2 Data collections ........................................................................................................................... 37
3.3 Sub City network data ................................................................................................................. 38
3.3.1 Reservoirs ................................................................................................................................ 38
3.4 Source of existing water supply .................................................................................................. 39
3.5 Water demand consumption and population data ...................................................................... 39
3.5.1 Water demand consumption .................................................................................................... 39
3.5.2 Population data ........................................................................................................................ 40
3.6 Verification of data’s .................................................................................................................... 40
3.7 Hydraulic Modeling ...................................................................................................................... 40
3.7.1 Assembling of the Model .......................................................................................................... 41
3.7.2 Model skeletonization............................................................................................................... 41
3.7.3 Friction factors .......................................................................................................................... 41
3.7.4 Demand allocation ................................................................................................................... 41
3.8 Procedure of the study ................................................................................................................ 44
3.9.1 Estimation of real loss .............................................................................................................. 45
3.9.2 Estimation of Apparent Loss .................................................................................................... 47
3.10 Performance Indicator (PI) ........................................................................................................ 47
3.10.1 Real Loss Performance Indicator ........................................................................................... 48
3.10.2 Apparent Loss Performance Indicator ................................................................................... 48
3.11 Limitations to the Study ............................................................................................................. 48
4. Results and Discussion 49
4.1 Analysis of water loss components ............................................................................................. 49
4.2 Water consumption ..................................................................................................................... 49
4.3 Model performance and evaluation criteria ................................................................................. 50
4.3.1 Pressure calibration and validation ................................................................................... 50
4.3 Real loss analysis ....................................................................................................................... 51
4.3.1 Network leakage ...................................................................................................................... 51
4.3.1.1 Determination of leakage coefficient “C” ............................................................................... 52
4.3.1.2 Nodal Leakage rate ............................................................................................................... 53
4.3.2 Leakage flow in the pipe .......................................................................................................... 54
4.3.3 Calculation of real loss performance indicator (PI) .................................................................. 55
4.4 Quantification of Apparent Loss .................................................................................................. 56
4.4.1 Losses due to unauthorised consumption ............................................................................... 56

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DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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4.4.2 Losses due to data errors ........................................................................................................ 57
4.5 Apparent Loss Index (ALI) calculation ........................................................................................ 57
4.6 Water balance ............................................................................................................................. 57
5. Conclusion and Recommendation 59
5.1 General........................................................................................................................................ 59
5.2 Conclusion .................................................................................................................................. 59
5.3 Recommendation ........................................................................................................................ 60
5.3.1 Data handling system ........................................................................................................ 60
5.3.2 Flow measurement ............................................................................................................ 61
5.3.3 Zoning and establishing DMAs ......................................................................................... 61
5.3.4 Upgrading of meter reading database .............................................................................. 61
6. References 62

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DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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LIST OF FIGURES
Figure 1-1: Map of study area .................................................................................................... 4
Figure 1-2: Location and feature of study area .......................................................................... 5
Figure 1-3; Areal view of Terminal Reservoir .......................................................................... 6
Figure 1-4: Non-Revenue Water over the period from 1986 - 2006 (EC) ................................. 7
Figure 2-1: Pressure and leakage relationship ......................................................................... 29
Figure 3-1: Aerial view of study area and distribution mains ................................................. 36
Figure 3-2: Schematics of modeled network of selected study area (Bole SC, Woreda-07)... 43
Figure 3-3: Diagram of study process ...................................................................................... 44
Figure 4-1: Demand pattern of the area ................................................................................... 49
Figure 4-2: Correlated plot of measured and computed pressure in bars ................................ 51
Figure 4-3: Correlation of pressure between volumetric and total consumption at nodes ...... 53

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DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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LIST OF TABLES
Table 1-1: Summary pipe lines in the study area ....................................................................... 6
Table 2-1: IWA best practice standard water balance ............................................................. 12
Table 2-2: Apparent annual volume losses of Addis Ababa 2003 E.C – 2006 E.C ................ 13
Table 2-3: Parameters required for calculation of components of annual real loss ................. 15
Table 2-4: Physical loss target matrix ...................................................................................... 20
Table 3-1: Residential water requirements .............................................................................. 39
Table 3-2: Parameters used in hydraulic modelling using WaterGEMS ................................. 42
Table 3-3: Inflow rate and pressure in 24 hours ...................................................................... 45
Table 4-1: Arrangement of pressure readings for calibration at the selected junctions ........... 50
Table 4-2: Estimated C values for each time interval .............................................................. 53
Table 4-3: Total leakage volume of nodes at each time interval ............................................. 54
Table 4-4: Total leakage of pipe at each hour .......................................................................... 54
Table 4-5: Water balance (m3) for the year 2007 E.C ............................................................. 58

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DEVELOPMENT OF A MODEL FOR ESTIMATING NRW IN ADDIS ABABA, THE CASE OF BOLE SUB CITY
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APPENDICES
APPENDICES A: - Reference location of junctions ............................................................... 65
APPENDICES B: - Pressure (bars) values of volumetric consumption and volumetric
consumption with leakage at minimum flow hour. ................................ 66
APPENDICES C: - Analysis of leakage at the junctions ........................................................ 67
APPENDICES D: - Analysis of leakage at the pipes .............................................................. 75

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