Tittle : Hydraulic performance Analysis of water supply distribution network using water GEM v8i

10 About concern to the growing population of the world, need water is increased gradually. On the other hand, the restrictions on freshwater resources, including surface and sub-surface water and their pollution by either point or non-point source pollutants have added the concerns over the health of drinking water. The study was evaluated the hydraulic analysis of the water distribution network using water GEMS v8i. which is used for modeling and Simulation of hydraulic parameters in the 15 distribution networks. The hydraulic parameters analyzed by using this software were junction pressure, water velocity the distribution system, and nodal demands, and the overall result of water supply did not satisfy demand. The water distribution system has been analyzed for steady-state and extended period simulation for the present population scenario for intermittent water supply using water Gems v8i. About 14 percent of the total number of nodes analyzed had negative pressures 20 while 68 percent of the nodes had pressures less than the adopted pressure for the analysis. These negative pressures indicate that there an inadequate head within the distribution network for water conveyance to all the sections. In the same manner, 85.6 percent of flow velocities in the pipes were within the adopted velocity while around 14.4 percent of the velocities exceeded the adopted velocity. The results in this study revealed that the performance of the water distribution system of 25 undercurrent demand is inefficient.


INTRODUCTION
Water is an essential element required for the sustenance of life, which play important role in the socio-economic development of a country (Ms. P. S. Salunke, An Overview of water 30 Distribution Network by Using Water GEMS Software, 2018; TINA MAV, 2019; Rameshwari D. Bhoyar1, 2017). However, approximately two and a half billion people on earth do not have access to safe drinking water (Pravinkumar Shinde 1, 2018;Berihun, 2017;Salunke, 2018;Wonduante, 2013), due to this, an acute crisis of water is looming time to time in this world, which is important to optimize the supply and reduce losses. According to, (Desalegn, 2015;Damgir, 2017;Rossman, 35 2000; THOMAS J. KUEHN, 2018;Zewdu A., 2014), the adequate provision of water supply distribution networks efficiently can eradicate poverty and ultimately provide the environment for sustainable development. However, water supply utilities in developing countries are faced with challenges of low service coverage and high unaccounted losses of water. The accessibility of the water supply system in most Ethiopian towns is becoming the most challenging in terms of its quality 40 and quantity to the water utilities. The estimated water supply service level of Ethiopia, interims of its coverage, quantity, quality, and reliability is very low (Desalegn, 2015;Damgir, 2017).
Consequently, water demand is increasing drastically due to the population growth rate and perurbanization of the town through this country. The hydraulic analysis of flows and pressures in a distribution system has been a standard form of engineering analysis since its development by Hardy 45 Cross in 1936 (Affairs, 1936). The demand usually reaches a peak in the morning when people are at home and preparing their meal and its second peak in the evening maximum water use and minimum water use, usually related to average water use by multiplication of peaking factors (Maina, 2015). The prime purpose of water supply distribution networking was for delivering access water supply for the required station with efficient pressure and velocity after the treatment plant 50 (Rameshwari D. Bhoyar1, 2017). This distribution network is an essential hydraulic infrastructure that is a part of the water supply system composed of a different set of pipes, hydraulic devices, and storage reservoirs (Pravinkumar Shinde 1, 2018). The distribution system of a waterworks consists of the pipes, valves, hydrants, and appurtenances used for distributing the water, the elevated tank and reservoir used for fire protection and for equalizing pressures and pump discharges and meters 55 (Izinyon and B. U., 2010; Ms. P. S. Salunke, An Overview: Water Distribution Network by Using Water GEMS Software, 2018). Water GEMS track flow of water in each pipe, the pressure at each junction, the height of water in each tank, and the concentration of water throughout the network during a simulation period.

Study Area Description
The study was conducted in Oromia Regional State of Alibo town, East Wellega Ethiopia which is located 365 km from Addis Ababa which is located at an altitude of 2410m above sea level in the into three seasons, those are, Summer season on which the average max and min temperature is 27.63 º C and 8.73 º C respectively, were as in the Autumn season; the max and min temperature 28.7 º C and 11.5 º C, and, for the Winter season the max and min temperature is 27.13 º C and 11.2 º C.

Study design flowchart for a methodology
Research design is referred to as a master plan, blueprint, and even a sequence of research tasks. Hence, this study is exploratory, descriptive, and applied study.

Input Data Collection
The input data required for hydraulic network modeling were associated with the component of a distribution network for each link. This data can collect in each node of pipe link are, pipe label, pipe material, pipe length, pipe diameter, starting node, stopping node, and pipe roughness are some of the pipe input data requires for the modeling and simulation of water distribution network. The other 80 input data associated are pressure junctions at node/link which includes junction label, junction elevation, and junction demand. Tank data requires are base elevation, minimum elevation, maximum elevation, initial elevation, and tank diameters. The pump input data collection is design flow, maximum operation flow, design head, maximum operating head, maximum operating head, shut-off design, and coordinate system.

Estimation of present and future water demand deficit
The design and execution of any water supply scheme require an estimate of the total amount of 110 water required by the community. Designing the water supply scheme for a town is necessary to determine the total quantity of water required for various purposes for Alibo town has categories.

Domestic Water Demand
The water demand for actual household activity is known as domestic water demand. The demand was reliant on many factors, the most important of which are economic, social, and climatic factors.

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The water demand is calculated for the domestic water demand, per capita domestic water demand, non-domestic water demand, and institutional water demand, commercial water demand, industrial water demand.

Non-Domestic Water Demand
Accordingly, estimated domestic water demand is 10% for institutional and commercial demand, 120 10% for industrial water demand and 5% for firefighting water demand were added to get the average daily water demand.

Model Calibration and Validation
The study was measured the water pressure to evaluate the model performance. The method of pressure readings was done from Feb 24, 2020, to Mar 01, 2020, using pressure gauge meters were 125 commonly taken both at the higher and lower zone of the selected points in distribution network; such as raw water pump stations, service reservoir, public fountains and different end-user taps. In this way, the perceived pressure data was taken a total of 10 samples for peak demand time analysis five samples were taken from the lower zone and five samples from the higher zone. From pressure junction and its coordinate system were collected for 10 nodes as a sample for validation of the study 130 result (J-45, J-12, J-1, J-43, J-10, J-61, J-54, J-76, J-28, and J-87) measured near the corresponding location using a pressure gauge.

Hydraulic Parameter Modeling
The design criteria used in the design of pressure zone boundaries, nodal pressure during the period of peak demand, and optimum velocities of the transfer and distribution mains are (pressure and 135 velocity).

Pressure:
The operating pressures in the distribution network according to the MoWR (2006) urban water supply design criterion shall be 15m to 80 ranges. Accordingly, MoWR reports that there are two main criteria to determine the pressure in the distribution networks whether it's in the ranges of scope.

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Velocity: According to the MoWR urban water supply design criterion water velocities shall be maintained at less than 2 m/sec, except in short sections & for pumps. Velocities in small diameter pipes may need even lower limiting velocities. A minimum velocity of 0.3 m/sec can be taken, but for looped systems, there are also pipelines with sections having a velocity <0.1m/sec.This shows that a pipe designed to flow at a velocity between 0.6 and 2 m/sec, depending on diameter, is 145 usually at optimum condition. The shortest sections, particularly at special cases, at inlet and outlet of pumps, may be designed for higher velocities.

Population projection
Among different techniques of population projection methods, the study analyzed the minimum error 150 and used the arithmetic method for estimation of population. Accordingly, the projected population at the end of the design period was 197000 of population, which implies that the current populations were increased by 47000 populations on water consumption. Therefore, Alibo town population For this projected population (Fig 4), based on the study area capacity, climates of the study area, socioeconomics and other limited resources, the average water demand varied from 20 L/c/d to 25 l/c/d at the end of the design period (2035)

Prediction of future water demand deficits
The estimated water demand deficits versus water supply production of the study area were plot in below Figure 6. Accordingly, the productions of water supply for were only meeting the water demand requirement for different consumption rates averagely up 2020 years. Beyond to this year water requirements of the town were less than year water production to the area due to limited supply 195 and water demand was becomes day to day distressing.

Analysis of water demand variation in distribution networks
The consumption of water by urban population, based on different factors among those climate condition, socio-economic, topographic area and others determine the demand of urban area which is depend on distribution network performance of the systems. As far as distribution of water is 210 concerned, the properties of hydraulic parameters in distribution network allowable limit were estimated and based on this issue the peak hour demand (187.5 l/s) of design period (2035) simulation of Water GEMS V8i. For this study the peak hour factor is greater for a smaller population and hence, this peak hour demand result did not match with that of the growing population of the town and this demand can vary from each distribution network as shown in Figure 7. As described in the Figure 7 the blue, magenta and brown color were indicate the demand value have been less than or equal to 1 L/s, 3 L/s and 8 L/s, respectively. This indicated that, almost more than 220 half of the study area nodal water demand was obtains greater than or equal to 8 L/s as justified in

Analysis of Pressure in the Networks
The water distribution network was designed based on pressure criteria and the existing criteria on the minimum and maximum pressure in the network. The operating pressures in the distribution 225 network according to the Minister of water resources, urban water supply design criterion shall be 15m to 80m ranges. Accordingly, this study result of the pressures distribution networking is avail in within this ranges. However, as the researcher analyzed, negative pressure was observed/recorded in 8 junctions, which shows that no water flows/ currents reached this segment of the distribution network, which was no provisioning of water to the consumers. This negative pressure may occur 230 due to the size of the pipe, and levels of water, avail in the distribution network which has a great impact on societies. It was attempted in the design to meet the optimal diameter and minimum pressure in the network as shown in Figure 8. Accordingly, the study considers low peaks through night hours the pressure in the system becomes high and the leakage loses expected to increase whereas at high peaks the pressure becomes small and the leakage losses expected to decrease. High 235 value of pressures affects adversely the hydraulic performance of the distribution network at night time (4:00 AM) during low consumption period, the pressure in the system become high.  Table 1. The result of simulation run was obtained after model constricted from the input of existing data a total node of 231 was reported from the project inventory dialog box software. between 15 mH2O and 60 mH2O and 3.77 % of the node has above 60 mH2O. This implies that the percentage of permissible pressure for Alibo town water supply distribution system was lower than Tulu bolo town. Due to source position and topographical circumstance of Alibo town water supply distribution network permissibility of pressure distribution was lower than Tulu bolo town.

Analysis of Network Profile
The software has the potential to give a variety of information, including hydraulic profile, velocity profile, and pressure gradient at any point in the network to the user. One of the town s mainline is shown in the figure with respectively.
265 Figure 9. Elevation profile of the distribution from a reservoir to end customer pipes In the distribution main lines of the study area, the locations of nodes in the water distribution line are near each other. The maximum and minimum water pressure in the distribution system was 98.45 and 8m from the reservoir head to the ends of the customer services pipe. According to the design 270 criteria of the FDRE; a Minster of water, irrigation, and energy, the maximum and minimum water pressure in the distribution system is 80m and 15m, respectively. This water was delivered to the distribution main by gravity means, and the system was served beyond its design life. Nodes having low values of pressure, Steady-state Analysis (5 ≤ P ≤ 10m) and Nodes having high values of Pressure, Steady-state analysis (80 ≥ P ≤ 98.45m). The hydraulic grade line and base elevation starting 275 from the Tank to the distribution system were plotted as shown in Figure 10.

Analysis of Pump capacity
The amendment of pump is one of the important elements, which add energy to the system. Since water can flows from the higher energy location to the lower energy. Pumps used to boost the head 290 at desired locations to overcome desired piping head losses and physical elevation difference for future required volume of water distribution network. A pump curve represents the relationship between the head and flow rate can deliver water at nominal speed settings. Pump head is the head gain imported to the water by the pump and plotted on the vertical of the curve in meter. According to field observed data and model-simulated result, the pump brake horsepower, and maximum water 295 power were collected as 55.83 kW and 24.4 kW, respectively. Therefore, 78.67% of the pump efficiency was shown that currently these pumps were operating in a good performance and did not deliver sufficient water to the treatment plant continuously.  A pump is defined by its characteristic curve, which relates the head added to the system to the flow rates. As described on Figure 11, the red colour shows as the head decreases the amount of discharge pushed by the pump increases. While the blue colour shows as the pump efficiency decrease the amount of discharge pushed by the pump increase.  the continuity and energy conservation equations (Rossman,et al., 2000).

Velocity Analysis
Although the both design guide line have different values on the same idea, the study was conducted using velocity standards given by MoWR water supply design criteria (2006). High consumption of water was occurred at morning time (8:00 AM). comparing the permissible velocity value of Tulu bolo town with Alibo town, the Alibo town velocity value was more permissible. The diameter of pipes distributed in Alibo town half of water supply distribution network was effective for satisfactory flow of water; this was the reason why Alibo town water supply distribution network velocity values were more permissible.

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The study analysis the main challenges of water distribution networks, which could limit the quantity of water supply due to the volume of existing reservoirs size and pre-urbanization (population expansion). To provide the minimum pressure and prevent increasing pressure which increases in water tragedies and unnecessary use of water, pressure should be carried out by the appropriate selection of the tank and pressure zoning of the network. The existing water distribution network of 350 Alibo town was designed for an estimated population of 69,160. However, the current population figures out 118,339, which is being served beyond the design life and low coverage in the town, which causes scarcity of drinking water supply in the town. Accordingly, there was a complaint from the customer because their demand was not being met to fulfill their satisfaction since the distribution system is intermittent. In the distribution network system, the same velocity can be less than the permitted level of MoWR and the negative pressure junction can also occur in the systems of networking distribution. Some of 360 the nodes have low values of pressure, steady-state analysis (-5 ≤ P ≤10m), and nodes having high values of pressure, steady-state analysis (80 ≥ P ≤ 128.45m). The software finds the lowest allowable diameter for each pipe segment that allowed the system to function, or more specifically, to meet the minimum pressure requirements at all junctions.