Table 2 lists the relevant parameters and a comment to describe how each parameter was defined. Land use was considered by classifying each model according to the predominant land use, as type A (general residential) or type B (low-income residential).
Table 2
Model parameters
| Parameter | Unit | Definition |
|---|---|---|
| Total pipeline length | km | Sum of the lengths of all individual pipes in the WDS. Total pipeline length per diameter was also recorded. |
| Peak flow rate | L/s | Hydraulic models were populated with the hourly peak flow rate, which is derived from the average annual daily demand (AADD). The AADD is widely used for problems relating to research and design in South Africa and is also used in other Southern African countries, for example, in Malawi (Makwiza & Jacobs 2016). The minimum pressure during peak hourly demand is widely used when considering minimum system pressure (Ghorbanian et al. 2016). |
| Land area | ha | The area of each WDS was approximated by an ellipse, the major axis d1 is the line joining the two furthest points, and the minor axis d2 is the longest possible perpendicular bisector of d1. The area of the ellipse is then:  . |
| Area shape factor | – | Defined as the ratio of d1 to d2, describing the elongation of the ellipsoidal area. |
| Terrain index | – | The average value between the range and standard deviation indices for the WDS, as discussed below and determined using Tables 3 and 4. |
| Reservoir distance from area centroid | m | Distance between coordinates of reservoir and ellipse centroid. |
| Average static system pressure | m | Difference in height between reservoir full supply level and mean elevation of all WDS model nodes. |
| Parameter | Unit | Definition |
|---|---|---|
| Total pipeline length | km | Sum of the lengths of all individual pipes in the WDS. Total pipeline length per diameter was also recorded. |
| Peak flow rate | L/s | Hydraulic models were populated with the hourly peak flow rate, which is derived from the average annual daily demand (AADD). The AADD is widely used for problems relating to research and design in South Africa and is also used in other Southern African countries, for example, in Malawi (Makwiza & Jacobs 2016). The minimum pressure during peak hourly demand is widely used when considering minimum system pressure (Ghorbanian et al. 2016). |
| Land area | ha | The area of each WDS was approximated by an ellipse, the major axis d1 is the line joining the two furthest points, and the minor axis d2 is the longest possible perpendicular bisector of d1. The area of the ellipse is then: . |
| Area shape factor | – | Defined as the ratio of d1 to d2, describing the elongation of the ellipsoidal area. |
| Terrain index | – | The average value between the range and standard deviation indices for the WDS, as discussed below and determined using Tables 3 and 4. |
| Reservoir distance from area centroid | m | Distance between coordinates of reservoir and ellipse centroid. |
| Average static system pressure | m | Difference in height between reservoir full supply level and mean elevation of all WDS model nodes. |