Service Contract No 2007 / 147-446 - Swaziland

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d1.5d0.5dd3d 3d 1.5dFigure 9. Spacing and placing of suction pipe inletsA proper intake structure was constructed for phase two river pump station and some of theabove requirements are not satisfied (figure 10). For example the suction pipes are installedtoo close to the sump. Over the years the level of the Usuthu River has dropped and adiversion channel is used to redirect water back into the sump.Figure 10. Intake sump and suction pipes for PS 2A proper intake structure was not constructed in PS 1 instead the suction inlets (foot valves)are suspended at the end of another diversion channel from the Usuthu River (figures 9). Thefoot valves are not protected in any way and are intermittently in direct contact with thebottom of the channel and debris carried with the river water.The evaluation revealed that this FA loses at least a week every month as a result of a dropin the river level and sand accumulation along the banks. Occasionally farm managementconstruct a diversion channel using sand bags rerouting water back into the suction inlets.Maphobeni Farmers Association Report - 2009 Page - 19 -
Phase two booster pumps are supplied from the adjacent small earth dam and the outlet ofthe dam does not have strainers. The outlet pipe is approximately 1.5m form the bottom ofthe dam. The installation height of the outlet pipe reduces the effective storage capacity of thedam by almost a third.The minimum water depth above suction pipe inlet depends on the suction pipe velocity andwas evaluated using the graph shown in figure 14 below. Site investigation revealed that PS1 and PS 2 foot valves are 200mm and 700mm below the water level respectively. With asuction velocity of 2.1 and 1.1m/s the depth should be at least 1.1m and 0.75m respectivelyas indicated in figure 11 below.Figure 11. Minimum water depth above suction pipe inletPhase two booster pumps are installed at a lower level than the minimum water level in thereservoirs, which ensured that there is always water in the pump casing and suction pipe.This is the most preferred pump design criteria and installation was in accordance to thestandards.4.1.1.4 Suction side lossesDuring the evaluation of the pump station, attention is also given to the length of the suctionpipe and fittings that were used. Friction losses for pipes are calculated as for any other pipe(using Hazen-Williams equation) and secondary losses for fittings are calculated with the aidof the following formula:Maphobeni Farmers Association Report - 2009 Page - 20 -
Page 1 and 2: Restructuring and DiversificationMa
Page 3 and 4: DISCLAIMERThe contents of this repo
Page 5 and 6: 5.2 Delivery tests ................
Page 8 and 9: LIST OF APPENDICESAppendix 1: SEB u
Page 10 and 11: 1 I N T R O D U C T I O NAssociatio
Page 12 and 13: pumps. 2 x Howden 100-400 in the ri
Page 14 and 15: 3.1.2 R e v i e w o f C o n t a c t
Page 16 and 17: 9 SCHEDULE OF BLOCKS THAT IRRIGATE
Page 18 and 19: Maphobeni Farmers Association Repor
Page 24 and 25: Based on equation 1 above the flow
Page 26 and 27: ReducersThe inlet on the pump sucti
Page 30 and 31: hf6375kQ4d2……………………
Page 32 and 33: Table 1. Pump and motor specificati
Page 34 and 35: Table 2. Irrigation pumps evaluatio
Page 36 and 37: Phase two river pump station‣ Pum
Page 38 and 39: Filters: 3%Capital Recovery Rate (C
Page 40 and 41: 4.3.1 M a i n l i n e s i z eThe So
Page 42 and 43: 5 F I E L D E V A L U A T I O N O F
Page 44 and 45: 5.1.2 S p r i n k l e r p r e s s u
Page 46 and 47: 0 L/4 L/2 3L/4 LL3L/4LL/2Test block
Page 48 and 49: Phase two booster Pumps running und
Page 50 and 51: The installation of this unit (on t
Page 52 and 53: Old AgePhase one of the irrigation
Page 54 and 55: The effects of different nozzles/em
Page 56 and 57: Interest RatesIt can be argued that
Page 58 and 59: 6 . 2 M a n a g e m e n t P r a c t
Page 60 and 61: 6 . 3 M a i n t e n a n c e S u r v
Page 62 and 63: 7 C O N S T R A I N T S T O E F F I
Page 64 and 65: phase one and two was found to be 1
Page 66 and 67: 8 R E C O M M E N D A T I O N STo e
Page 68 and 69: OVERALL MANAGEMENT AND MAINTENANCEM
Page 70 and 71: 10 L I T E R A T U R E R E F E R E
Page 72 and 73: 11 P R O D U C T I N F O R M A T I
Page 78 and 79:
Maphobeni Farmers Association Repor
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
SEB usage for River pump station Ph
Page 88:
Appendix 2: capital recovery factor
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Service Contract No 2007 / 147-446 - Swaziland

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