Performance Evaluation Of Water Supply System Using Watercad And Epanet

ABSTRACT

Population explosion in urban settings usually exerts enormous pressure on existing water supply systems. The result is that overall water demand is usually not satisfied. This study evaluated the performance of Ahoada sub-zone water distribution system with respect to pressure, velocity, hydraulic head loss and nodal demands using WaterCAD and Epanet. There was no statistical difference between the results of Epanet and WaterCAD, however, Epanet produced slightly higher results of pressure and velocity in about 60% of all cases examined. About 19 percent (18.52%) of the total number of nodes analyzed had negative pressures while 69 percent (69%) of the nodes had pressures less than the adopted pressure for the analysis. These negative pressures indicate that there is inadequate head within the distribution network for water conveyance to all the sections. About 88 percent (87.7%) of flow velocities in the pipes were within the adopted velocity while around 12 percent (12.3%) of the velocities exceeded the adopted velocity. These excess velocities are partly responsible for the leakages and pipe bursts observed at some points within the system. The results in this study revealed that the performance of the water distribution or supply system of Ahoada sub-zone under current demand is inefficient.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

• INTRODUCTION
• BACKGROUND OF THE PROJECT
• AIM OF THE STUDY
• OBJECTIVE OF THE STUDY
• SIGNIFICANCE OF THE STUDY
• IMPORTANCE OF THE WATER DISTRIBUTION SYSTEM
• LIMITATION OF THE STUDY
• REQUIREMENTS OF GOOD DISTRIBUTION SYSTEM

CHAPTER TWO

LITERATURE REVIEW

• INTRODUCTION
• LITERATURE REVIEW OF EPANET AND WATERCAD
• REVIEW OF WATER SUPPLY
• THE IMPORTANCE OF WATER FROM HISTORICAL PERSPECTIVE
• CHALLENGES OF WATER SUPPLY IN NIGERIA
• FACTORS MILITATING AGAINST THE PROVISION OF POTABLE WATER IN NIGERIA
• CONSEQUENCES OF INADEQUATE WATER SUPPLY IN NIGERIA

CHAPTER THREE

3.0       METHODOLOGY

• DETAILS OF SOFTWARE
• HYDRAULIC MODELLING CAPABILITIES
• STUDY AREA
• DATA COLLECTION
• WATERCAD AND EPANET SIMULATING MODEL
• SKELETONIZATION OF WATER DISTRIBUTION NETWORK AND MODEL CONSTRUCTION

CHAPTER FOUR

4.0       RESULTS AND DISCUSSION

• RESULTS AND COMPARISON OF THE TWO MODELS
• VELOCITY FLUCTUATION OF WATERCAD/EPANET SIMULATORS
• PRESSURE DISTRIBUTION WITH AND WITHOUT VALVES
• NODAL DEMAND AT VARIOUS JUNCTIONS
• OUTPUT OF FLOW RATES IN THE SYSTEM
• IMPROVEMENT OF THE WATER DISTRIBUTION NETWORK

CHAPTER FIVE

• SUMMARY
• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                                   INTRODUCTION

Water distribution systems are designed to satisfy the water requirements for domestic, commercial, industrial, and fire-fighting purposes. The system should be capable of meeting the demands and pressures at each node within the distribution system at all times. Hydraulic analysis of water distribution system is an essential step towards understanding the behaviour of water supply and distribution system which includes the flow, pressure, velocity, head loss, efficiency and operation point of each pump.

Water distribution system may include facilities for collection, storage, transportation, pumping, treatment and distribution. Of the total expenditure incurred on different facilities of a water distribution system, the expenditure incurred on transportation and distribution of water is quite large and may even exceed 70%. A drinking water distribution system must be able to supply water to all consumers at their delivery points throughout the design period. Water distribution systems deteriorate over time. The American Water Works Association (AWWA) estimated in the Distribution System Inventory, Integrity and Water Quality publication that there are close to 2,37,600 breaks per year in the US during the year 2010. It is not economically viable to replace all deteriorating pipelines in aging water distribution systems. Therefore, careful planning of maintenance activities for water distribution systems is essential. Optimal rehabilitation and maintenance strategies will not only save money but also will improve the level of service, increase the satisfaction of customers, enhance the life and reliability of the water distribution systems.

1.1                                          BACKGROUND OF STUDY

Water supply systems are among the most important public utilities, because safe supply of potable water is the basic necessity of mankind in any given municipality (Swamee & Sharma 2008). In 2010, an estimated amount of about 85% of the world’s population (i.e. 6.74 billion (10⁹) people) had access to piped water supply through house connections (Anisha et al. 2016). These connections form an integral part of the master plan for communities, countries, and municipalities. Abdulkadir & Sule (2012) noted that a distribution system must supply water of good quality, in adequate quantities and at sufficient pressure to meet system requirements to the users. Generally, a water supply system comprises of intake works, treatment works, transmission mains, storage and distribution network (Swamee & Sharma 2008). The components of a distribution system are pipes, valves, hydrants and appurtenances used for distributing the water, elevated tanks and reservoirs used for fire protection and for equalizing pressure, and pump discharge and meters (Ayanshola et al. 2013). The cost of setting up a water distribution system is largely influenced by the accuracy of the hydraulic design and analysis, accounting for up to 80% of the total cost of the system (Garg 2005). As a result, the hydraulic modeling and analysis of a water distribution network should be given pre-eminence.

Modeling of a water distribution network is required for accurate and efficient design as well as optimal performance of a water distribution system both immediately after construction and in the future. The availability of increasingly sophisticated and accessible computer models allows these goals to be realized more fully than ever before. Computer-aided modeling and analyses is the new trend in the analysis of water supply systems, which took advancement from the initiative that started two millennia ago when the first piped system for fluid conveyance was constructed by the Minoans (Viyakesparan 2015). Walski et al. (2001) as cited by Adeniran & Oyelowo (2013) traced the development of water distribution systems and methods of analysis from wood pipes to modern piping materials; and from crude rule of thumb analysis to the lengthy long-hand iterative Hardy-Cross method to modern computer-aided design.

Many water distribution network modeling packages require input data from many sources, some of which cannot be measured directly and are not determined precisely. The main parameters considered in the hydraulic design of a water distribution system are pressure and hydraulic gradient (Abdulkadir & Sule 2012). However, as the system of pipes becomes increasingly complex, getting a precise estimate of the parameters mentioned becomes cumbersome. This has necessitated the quest for methods that can effectively and efficiently analyze the system (Henshaw & Nwaogazie 2015). The most commonly used theories for analyzing a water distribution network are Hardy-Cross, Newton-Ralphson and linear theories (Henshaw & Nwaogazie 2015). Most software for water distribution network analyses and design are based on these methods. While computer models enable fast and efficient analyses and design of water distribution networks, they can also be used to ascertain the performance of existing systems. Hence the aim of this work is to undertake a performance evaluation of Wadata water distribution system in Ahoada East LGA of Rivers State, Nigeria.

1.3                                                AIM OF THE STUDY

The aim of this work is to ascertain water distribution networks in Ahoada East LGA of Rivers State, Nigeria.

1.4                                         OBJECTIVES OF THE STUDY

1. To supply water equitably to the consumers with sufficient pressure.
2. The rehabilitation and improvement towards continuous water supply during 24 hours.

• To reduce the energy consumption in the pumping systems.

1. To analyse the existing water distribution system using EPANET and WATERCAD to suggest some measures if network does not fulfill the present and future demand.

1.5                                      SIGNIFICANCE OF THE STUDY

This study exposes students involved to the fast and efficient analyses and design of water distribution networks, they can also be used to ascertain the performance of existing systems.

Modelling water distribution systems with software is proved to be effective and reliable technology for simulating and analyzing system behaviour under a wide range of hydraulic conditions.

At present many software are available for improving efficiency of network. EPANET and WATERCAD are two of the important software used in the analysis of water distribution system.

1.6               IMPORTANCE OF THE WATER DISTRIBUTION SYSTEM

The drinking water is one of the essential elements required for all components to carry out the different fundamental activities of life. Due to rapid urbanization and water scarcity, maintaining a stable and safe water supply has become a challenge to many cities. The problems like inadequate supply of water with low pressure, pipe burst, excessive leakage and non revenue water are increasing exponentially. To overcome these challenges, water distribution system is needed.   

A water distribution system consists of three major components: pumps, distribution storage, and distribution piping network. Most of the water distribution systems require pumps to supply extra head to overcome the head loss due to friction. Storage tanks are included in the systems for emergency supply or for balancing storage to reduce energy costs. Pipes may contain flow-control devices, such as regulating or pressure-reducing valves. Water distribution network is represented by a series of links and nodes. A link has a node at each end. Nodes represent junctions, tanks and reservoirs, whereas links represent pipes.

A water distribution system typically includes

1. A drainage basin (sources of drinking water).
2. A raw water collection point (above or below ground) where the water accumulates, such as a lake, a river, or groundwater.

• Water purification facilities. Treated water is transferred using water pipes (usually underground).

1. Water storage facilities such as reservoirs, water tanks. Tall buildings may need to store water locally in pressure vessels in order for the water to reach the upper floors.
2. Additional water pressurizing components such as pumping stations may need to be situated at the outlet of underground or above ground reservoirs or cisterns (if gravity flow is impractical).
3. A pipe network for distribution of water to the consumers (which may be private houses or industrial, commercial or institution establishments) and other usage points (such as fire hydrants).

• Connections to the sewers (underground pipes, or aboveground ditches in some developing countries) are generally found downstream of the water consumers, but the sewer system is considered to be a separate system, rather than part of the water supply system.

Water distribution network is maintained at positive pressure to ensure that water reaches all parts of the network, that a sufficient flow is available at every take-off point and to ensure that untreated water in the ground cannot enter the network. The water is typically pressurised by pumps that pump water into storage tanks constructed at the highest local point in the network.

These systems are usually owned and maintained by local governments, such as cities, or other public entities. Water distribution networks are part of the master planning of communities, counties, and municipalities. Their planning and design requires the expertise of city planners and civil engineers. Consider many factors, such as location, current demand, future growth, leakage, pressure, pipe size, pressure loss, fire fighting flows, etc.

1.7                                        LIMITATION OF THE STUDY

There are other theories for analyzing a water distribution network such as  Hardy-Cross, Newton-Ralphson and linear theories but this study is limited to EPANET and WATERCAD method.

1.8                  REQUIREMENTS OF GOOD DISTRIBUTION SYSTEM

1. Water quality should not get deteriorated in the distribution pipes.
2. It should be capable of supplying water at all the places with sufficient pressure head.

• It should be easy to maintain and operate.

1. The layout should be such that no consumer would be without water supply, during the repair of any section of the system.
2. All the distribution pipes should be preferably laid one metre away or above the sewer lines.