**Constrains:**


### **3. Results and Discussions**

### *3.1. Distribution Network Layout*

A dead-end type of distribution network was drawn for both parts of the study area using EPANET 2.2, as shown in Figure 1a,b. The input data for nodes—elevation; base demand; and demand pattern—was provided for each node, and the input data for pipes—pipe diameter; roughness coefficient; and length—was provided. The pipe network was arranged for both WDS, keeping in mind the geometry of the study area; the dead-end type of distribution system was used for both parts of the study area. Moreover, the basic assumption of the Jal-Tantra web system of having no loops in the network has to be satisfied.

**Figure 1.** (**<sup>a</sup>**,**b**): Distribution Network Layout for WDS parts I and II.

#### *3.2. Contour Plan of Pressure Head at Nodes at 9 a.m. (Peak Demand Hour)*

The contour plans given in Figure 2a,b, show the distribution of the pressure head across the layout of the network, parts I and II. Different colours representing the range of the pressure head are depicted by the scale provided in each map. The analysis indicated that the pressure head at all the nodes is greater than 17 m, thus the water at each node can reach up to a minimum of three stories of the building [18]. There is no need to use the PSVS. Moreover, the pressure head is also less than 70 m at each of the nodes in both parts of the WDS, so there is no need to install the PRVs at any of the nodes.

#### *3.3. Colour-Coded Diagram of Velocity in Links at 9 a.m. (Peak Demand Hour)*

The colour-coded velocity diagram given in Figure 3a,b, shows the range of velocities of flow in each pipe of network parts I and II. The scale showing the range of velocity represented by each colour is given for each of the networks. The analysis indicated that the velocity of flow for all the pipes in both networks is in the range of 0.25 m/s to 3 m/s [18]. Thus, there is no danger of erosion and deposition in the pipes during peak flow.

(**a**) (**b**) 

**Figure 2.** (**<sup>a</sup>**,**b**): Contour plan of pressure head at nodes at 9 a.m., for WDS parts I and II.

**Figure 3.** (**<sup>a</sup>**,**b**): Colour-coded diagram of velocity in links at 9 a.m., WDS parts I and II.

### *3.4. Time Series Plots*

The temporal variation of the pressure head at the peak demand nodes and the water level in the tank are shown in Figure 4a,b, and the velocity in the pipes feeding the peak demand nodes is shown in Figure 4c,d. The pressure head lies within the recommended ranges with respect to all the nodes shown throughout the day. However, the velocity of flow in the pipes at the hours of minimum demand is less than 0.25 m/s, which can be attributed to the demand pattern adopted and the fact that the diameters have been selected to provide sufficient pressure head and cater to the demands at the peak hour. Moreover, the discharge in the pipes at these hours is less, and thus there is no serious hazard of deposition in the pipes. However, a velocity less than 0.25 m/s may be adopted to meet the hydraulic standards only if there is a suitable method of scouring the pipes [18].

**Figure 4.** (**<sup>a</sup>**,**b**): Time series plot of pressure at peak demand nodes and storage tank for WDS parts I and II. (**<sup>c</sup>**,**d**): Velocity in links feeding peak demand nodes for WDS parts I and II.

### *3.5. Performance Evaluation by TPI*

The TPI pressure and TPI velocity for WDS at the peak hour were evaluated for both parts of the study area. The TPI pressure for WDS part I = 1, indicating 100% efficiency of the

network in terms of pressure head at the nodes at the peak hour. The TPI velocity for WDS part I = 0.615, indicating 61.5% efficiency of the network in terms of the velocity of flow in the pipes at the peak hour. The TPI pressure and TPI velocity for WDS part II are 1 and 0.645, respectively. Indicating the efficiency in terms of pressure head at nodes = 100% and in terms of velocity in the links = 64.5%. The lower values of TPI velocity can be attributed to the lower values of velocity during off-peak hours due to the demand pattern adopted.

#### *3.6. Cost Optimization by Jal-Tantra Web System*

The optimized value of the cost of the WDS in terms of pipe diameters was achieved by minimizing pipe diameters while maintaining the minimum specified pressure head for the nodes, as given in Table 6. However, the total cost before and after the optimization is approximately the same because the minimization of diameters can be seen in a smaller number of pipes and equals a maximum of 50 mm. Moreover, there is an increase in diameter of about 25 mm in some pipe lengths. The smaller difference in the costs indicates the cost-optimal design of the WDS for the study area by EPANET 2.2.


**Table 6.** Cost results for pipes, WDS parts I and II.
