Rural water supply and water demand ... - Up To - SOPAC

[15]
A full hydraulic analysis based on the original system design and the measurements have been
carried out. Table 2 summarises the applied design criteria. These more modest criteria follow
standard procedures and are much more in line with the actual production of the source: 8.7 l/s as
production versus 6.02 l/s average flow, 7.82 l/s max. average daily flow 8 .
Table 2: Design parameters for hydraulic analysis
Village Mele Mele Maat Total
Population No. 2000 600 2600
Demand Daily [l/capita/day] 200 200 400
Total Demand [l/day] 400000 120000 520000
m3/day 400 120 520
Average Flow [l/s] 4.63 1.39 6.02
[m3/hour] 16.67 5.00 21.67
Daily Peak Factor [-] 1.30 1.30
Max Aver. Daily Flow [l/s] 6.02 1.81 7.82
Hourly Peak Factor [-] 2.40 2.40
Max.Hourly Flow [l/s] 14.44 4.33 18.78
Even the max. hourly Flow of 18.78 l/s does not come anywhere near the 37.8 l/s flow applied in the
original design.
The results of the hydraulic analysis have been summarised in Figure 5 to Figure 7 and Appendix 2.
They show that, assuming fully pressurised flow, pressure would be at all times in the range of 55 m
posing a hazard to a rather usually fragile house connection. On the other hand high pressure during
static or semi-static conditions (pipes fill fully during the night) yields a good explanation for the high
leakage levels in the system. However, since it is unlikely that the 150 mm pipe to Mele ever fills fully
the hydraulic analysis provides only limited information unless more is known about the real pressure
levels in the system. It is anticipated that this information can be gathered within the next two
months.
8 This base flow would be used to design the tank applying specific local demand pattern the flow.
[MR351 - Schölzel]