Service Contract No 2007 / 147-446 NYANYALI ... - Swaziland

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data on emitter characteristics this FA is applying 3.6mm/day on their 6 day cycle. Also,there is no scheduling tool to accurately determine the amount of water applied and/orrequired with every irrigation.Training of farm manager and his assistantsSwaziland Sugar Association and Ubombo Sugar endeavour to provide technical assistanceto this FA but based on the current condition of the irrigation system, more is still to be done.More focus has to be put into training this FA on operation and maintenance of the irrigationsystem and ensure that equipment are replaced with correct ones and by qualifiedtechnicians. This capacity building exercise will go a long way into improving efficiency in thisirrigation project.6 . 3 M a i n t e n a n c e S u r v e yWhen the impact of maintenance practices was evaluated, it was decided to classify theexisting maintenance practices followed by the producer, according to existing literaturesources as acceptable if it will not influence the performance of the system adversely andunacceptable/ineligible if it will impair the performance. The acceptable values are viewed asthe absolute minimum values for the sustaining of an acceptable Us value in the systemTable 5. Maintenance schedule for sprinkler irrigation systemsMonitor With each cycle AnnuallyInspect the system for leakagesXCheck system pressure and system flowXService air valves and hydrantsXCheck sprinklers for wear and replace springs, washers andnozzles where necessaryFlush mainlines -XTable 6. Maintenance practices implemented by Nyanyali FarmersMonitor Results ClassificationInspect the system for leakages Attend to leaks only UnacceptableCheck system pressure and system flow Never UnacceptableService air valves and hydrants Never UnacceptableCheck sprinklers for wear and replace springs,washers and nozzles where necessaryNeverUnacceptableFlush mainlines Never UnacceptableNyanyali Farmers Cooperative Report - 2009 Page - 33 -
7 C O N S T R A I N T S T O E F F I C I E N T S Y S T E MP E R F O R M A N C EThe following constraints were identified to have an effect on productivity once the system isoperated.Pump station:‣ There is no proper intake structure instead the suction inlet (foot valve) is suspended atthe bank of the Mkhondvo River. The foot valve is not protected in any way and isintermittently in direct contact with the bottom of the channel and debris carried with theriver water. Sand bangs are used to redirect the receding river water back into the sump,especially when the river level drops. The sump has no provision for cleaning, in order toclean this sump one has to swim in the crocodile infested river.‣ The water depth above suction inlets is within the recommended minimum but isexpected to decrease during the dry season. Under this condition air is sucked in withirrigation water and cavitates the pump. The effects of the shallow depth on the pumpsare reflected through vortex and pump cavitation. This significantly reduced pumpefficiency and performance.‣ Incorrectly sized fittings in suction and delivery manifolds affect system performance byincreases turbulence occurrences and cause irregular feeding of the pump hencecavitation. With such an installation wearing and maintenance cost of the pump willincrease.‣ The 55kW motor that drives this pump is correctly specified. These results will only beconclusive after accurately determining system pressure requirement. There is apossibility that the 80m indicated on the pump information plate is too correcting thiscould result in using a smaller motor. also, low speed, 4-Pole motors are preferred overhigh speed 2–Pole motors‣ The evaluation of pumps could not identify whether the pumps are optimally operating ornot because the pump was not in operation during the evaluation. The assessment wascarried out after a period of heavy rains which not only raised the river level but alsoconceded a lot of iron oxide. According to Nyanyali management irrigating during this timecauses this material to accumulate inside the pipelines and in the long run reduces theircapacity. Pump performance is, also, seriously affected when operated during the time,more so, because the iron oxide changes the specific gravity of the water. Thisevaluation, in any case could not have been conclusive because there is no flow meter tomeasure pump discharge.Nyanyali Farmers Cooperative Report - 2009 Page - 34 -
Page 1: Restructuring and DiversificationMa
Page 5 and 6: 8 RECOMMENDATIONS .................
Page 7 and 8: ABBREVIATIONSAbbreviationAEARCASAEC
Page 9 and 10: 2 B A C K G R O U N D O N I R R I G
Page 11 and 12: 3 T E C H N I C A L A U D I T R E P
Page 13 and 14: 7,1 Type type Vyrsa 70 Vyrsa 707,2
Page 15 and 16: Soil informationSoil properties use
Page 17 and 18: 4 F I E L D E V A L U A T I O N O F
Page 19 and 20: Figure 5. 2 x 300mm x 45° bends on
Page 21 and 22: 4.1.1.1.3 Suction Pipe InletsSpacin
Page 23 and 24: hf6375kQ4d2……………………
Page 25 and 26: Table 1. pump and motor specificati
Page 27 and 28: Figure 13. Inside Nyanyali pump hou
Page 29 and 30: pipe:Filters:Pumpingequipmentand el
Page 31 and 32: 4.1.3 S u p p l y S y s t e mThe ev
Page 33 and 34: When down -stream pressure falls be
Page 35 and 36: 5.1.1 S p r i n k l e r p r e s s u
Page 37 and 38: 6 A S S E S S M E N T O F O P E R A
Page 39: indication of the amount small grow
Page 43 and 44: ‣ The optimum sprinkler operating
Page 45 and 46: 8 R E C O M M E N D A T I O N STo e
Page 47 and 48: ‣ A consortium could be formed fo
Page 49 and 50: Accurate details are required also
Page 51 and 52: 12. Solomon K.H. 1988a, Irrigation
Page 53 and 54: Nyanyali Farmers Cooperative Report
Page 57 and 58: SEB usage for River pump station Ph

Service Contract No 2007 / 147-446 NYANYALI ... - Swaziland

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