Hydraulic Modeling and Improvement of Addis Ababa

172 Pages·2015·3.64 MB·English

SMF 2015 M.Sc. Research Thesis

Hydraulic Modeling and Improvement of Addis Ababa

Water Supply System (The Case of Bole Bulbula)

Saleamlak Muluken Fitaye
June, 2015

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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

ADDIS ABABA UNIVERSITY
SCHOOL OF GRADUATE STUDIES
ADDIS ABABA INSTITUTE OF TECHNOLOGY
SCHOOL OF CIVIL AND ENVIRONMENTAL ENGINEERING
HYDRAULIC MODELING AND IMPROVEMENT OF ADDIS ABABA
WATER SUPPLY SYSTEM

(The Case of Bole Bulbula)

A thesis Submitted to the School of Graduate Studies of Addis Ababa University in
Partial Fulfillment of the Degree of Master of Science in Civil Engineering.

(Major in Hydraulic Engineering)

By: Saleamlak Muluken
Advisor: Geremew Sahilu (Dr.Ing)

June 2015
Addis Ababa, Ethiopia

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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

ADDIS ABABA UNIVERSITY
SCHOOL OF GRADUATE STUDIES
ADDIS ABABA INSTITUTE OF TECHNOLOGY
SCHOOL OF CIVIL AND ENVIRONMENTAL ENGINEERING

HYDRAULIC MODELING AND IMPROVEMENT OF ADDIS ABABA
WATER SUPPLY SYSTEM (The Case of Bole Bulbula)

(Major in Hydraulic Engineering)

A thesis Submitted to the School of Graduate Studies of Addis Ababa University in
Partial Fulfillment of the Degree of Master of Science in Civil Engineering.

By

Saleamlak Muluken Fitaye

Approved by Board of Examiners

Geremew Sahilu (Dr.Ing)

Advisor
----------------------------------------------- ---------------------------

Signature
Internal Examiner

----------------------------------------------- --------------------------
Signature
External Examiner

------------------------------------------------ -------------------------
Signature
Chairman (department of graduate committee)

------------------------------------------------- ---------------------------
Signature

June, 2015
Addis Ababa, Ethiopia

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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

Declaration

This thesis is my original work and has not been presented for a degree in any other university and that all
sources of material used for this thesis have been dully acknowledged.

Declared by

Saleamlak Muluken Fitaye
Name: ________________________________________
Signature: ______________________________________
Date: ____________J_u_n__e_,2__0_1_5____________________

Confirmed by

Name: ________________________________________
Signature: _____________________________________
Date: _________________________________________

Place and date of submission: Addis Ababa, June, 2015

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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

ABSTRACT

In this study, Addis Ababa Water distribution system for case study of Bole Bulbula supply system was
assessed. The main objective of this study is to improve the Bole Bulbula water supply distribution
system and control its operation, Water CAD software was used as tool to model water distribution
system analysis. The modeling effort included both hydraulic and water quality modeling. Simulation
results for maximum and minimum pressures were used as base tool to evaluate the hydraulic
performance; and simulation result for water age and minimum residual chlorine were used as base to
assess water quality transformation in distribution systems. Modeling results showed violation of
maximum and minimum pressure requirements. Along with this, water quality simulation results
illustrated water quality deterioration due to availability of minimum residual chlorine which is below
WHO guideline.

The model analysis result shows the different problems of the system. These are aged pipes, oversized and
undersized pipes, low and high pressures and water quality status. The system should be modified using
the design criteria of velocity, pressure and residual chlorine. High pressures in the existing system caused
by customers at too low demand have to be identified and solution is established using pressure-reducing
valves. To retrieve the situation there is a need to intervene. Modification in operation and design will
improve the current situation of the case study water distribution system.

Key Words: Water distribution system, modeling, Hydraulic performance, Water quality, Maximum
pressure, Minimum pressure, Water age, Residual chlorine, Bole Bulbula, Addis Ababa.

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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

ACKNOWLEDGEMENT

Above all I would like to thank God for giving me strength and patience from the beginning up to now in
all my life.

First and foremost I am deeply grateful to my advisor Dr. Geremew S.; for his dedicated and critical
comments and closer supervision of the whole work for otherwise the thesis would not have been possible
and completed on time. I am also indebted to and give special thanks to family for their encouragement
and motivation during my study.

Finally, I wish to thank all those who have helped me by one way or another during this
research.

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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

Table of Contents
Declaration ...................................................................................................................................... i
ABSTRACT.................................................................................................................................... ii
ACKNOWLEDGEMENT ........................................................................................................... iii
LIST OF FIGURES ..................................................................................................................... vii
LIST OF TABLES ........................................................................................................................ ix
Abbreviations and Acronyms ...................................................................................................... xi
1. INTRODUCTION ..................................................................................................................... 1
1.1 Background ............................................................................................................................ 1
1.2 Statement of the Problem ....................................................................................................... 3
1.3 Research Questions ................................................................................................................ 4
1.4 Research Objective................................................................................................................. 4
1.4.1 General objective: ............................................................................................................ 4
1.4.2 Specific objectives: .......................................................................................................... 4
1.5 Significance of the Study ....................................................................................................... 4
1.6 Overview of the Thesis .......................................................................................................... 5
1.7 Location of the Study Area..................................................................................................... 6
1.8 Existing Water Supply Sources of Addis Ababa City ............................................................ 8
1.9. Existing Situation of Water Distribution System ................................................................ 10
1.9.1 The System Water Source .............................................................................................. 10
1.9.2 Water Transmission Facilities ........................................................................................ 11
1.9.3 The Secondary Network of Bole Bulbula Water Supply System .................................. 11
1.9.4 Network Pipe Coverage in the System .......................................................................... 12
1.9.5 Water Distribution Facilities .......................................................................................... 12
1.9.6 Tertiary Network – Delivery to the customer ................................................................ 14
2. LITERATURE REVIEW...................................................................................................... 15
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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

2.1 Introduction .......................................................................................................................... 15
2.2 Definition ............................................................................................................................. 15
2.3 Historty of Hydraulic Modeling ........................................................................................... 15
2.4 Applications of Water Distribution Models.......................................................................... 16
2.5 Modeling a System Using Water CAD ................................................................................ 17
2.6 Types of Water Distribution Simulation ............................................................................... 18
2.6.1 Steady State Simulation ................................................................................................. 18
2.6.2 Extended Period Simulation .......................................................................................... 19
2.7 Principles of Network Hydraulics ........................................................................................ 21
2.7.1 Conservation of Mass .................................................................................................... 21
2.7.2 Conservation of Energy ................................................................................................. 22
2.8 Water Quality Modeling ....................................................................................................... 24
2.8.1 Advective Transport in Pipe........................................................................................... 24
2.8.2 Water Age Analysis ........................................................................................................ 25
2.9 Model Calibration and Validation ........................................................................................ 26
2.9.1. Hydrualic Model Calibration ........................................................................................ 26
2.9.2 Water Quality Model Calibration................................................................................... 26
2.9.3 Calibration and Validation Using Time Series Data ...................................................... 27
2.10 Water Demand .................................................................................................................... 27
2.10.1 Classification of Demand ............................................................................................ 28
2.10.2 Demand Mulitipliers .................................................................................................... 32
2.10.3 Time Varying Demands ............................................................................................... 33
2.11 Pressure and Leakage ......................................................................................................... 34
2.11.1 Negative Pressures ....................................................................................................... 37
2.11.2 Pressure Management .................................................................................................. 37
2.12 Water Loss in the Subsystem.............................................................................................. 38
2.13 Review of Related Works ................................................................................................... 40
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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

2.14 Conclusion.......................................................................................................................... 44
3. RESEARCH METHODOLOGY ........................................................................................... 45
3.1 Introduction .......................................................................................................................... 45
3.2 Research Process .................................................................................................................. 45
3.3 Data Collection..................................................................................................................... 47
3.3.1 Secondary Data Collection ............................................................................................ 47
3.3.2 Primary Data Collection ................................................................................................ 48
3.4 Data Preparation ................................................................................................................... 51
3.4.1 Water Line Network....................................................................................................... 51
3.4.2 Domestic Water Supply Coverage ................................................................................. 51
3.4.3 Water Loss Calculation .................................................................................................. 52
3.4.4 Water Demand Estimation ............................................................................................. 53
3.5 Modeling the Existing Distribution System ......................................................................... 58
3.5.1 Existing Data ................................................................................................................. 58
3.6 Data Entering........................................................................................................................ 61
3.7 Model Representation .......................................................................................................... 62
3.8 Model Calibration and Validation ........................................................................................ 62
3.9 Data Analysis and Presentation ............................................................................................ 62
4. RESULTS AND DISCUSSION............................................................................................... 65
4.1 Existing Water Supply Evaluation ....................................................................................... 65
4.1.1 Domestic Water Supply Coverage ................................................................................. 65
4.1.2 Water Balance ................................................................................................................ 66
4.1.3 Water Loss in the Subsystem ......................................................................................... 67
4.1.4 Population Forcasting .................................................................................................... 69
4.1.5 Diurnal Curves of the Addis Ababa Water Supply System for Domestic Demand ....... 69
4.1.6 Current and Future Water Demand in the Study Area ................................................... 70
4.1.7 Existing Water Supply System Gap Identified .............................................................. 71
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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System
SMF 2015 M.Sc. Research Thesis

4.2 Model Analysis..................................................................................................................... 72
4.2.1 Steady-state Analysis ..................................................................................................... 72
4.2.2 Extended Period Simulation .......................................................................................... 72
4.2.3 Model Calibration and Validation .................................................................................. 73
4.2.4 Calibration Standards..................................................................................................... 73
4.2.5 Calibrating Hydraulic Network ..................................................................................... 76
4.2.6. Model Performance Evaluation .................................................................................... 76
4.2.7 Calibrating Water Quality Modeling ............................................................................. 79
4.2.8 Validation ....................................................................................................................... 80
4.3 Identified Problems and System Design Improvements ...................................................... 81
4.3.1 Pressure .......................................................................................................................... 81
4.3.2. Velocity Distribution in Actual Pipe ............................................................................. 86
4.3.3 Water Quality in the System .......................................................................................... 87
4.4 Relationship between Pressure, Leakage and Water Quality for Water Supply System ...... 94
4.4.1 Relationship between Pressure and Leakage ................................................................. 94
4.4.2 Relationship between Pressure, Velocity and Water Quality ......................................... 95
4.5 System Model Improvements............................................................................................... 97
4.5.1. Hydraulic Network Improvement ................................................................................. 97
4.5.2. Water Quality Improvement ....................................................................................... 104
5. CONCLUSION AND RECOMMENDATION ................................................................... 108
5.1 Conclusion.......................................................................................................................... 108
5.2 Recommendation................................................................................................................ 109
REFERENCES .......................................................................................................................... 112
APPENDIX................................................................................................................................. 117

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Hydraulic Modeling and Improvement of Addis Ababa Water Supply, the Case of Bole Bulbula System