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

Restructuring and DiversificationManagement Unit (RDMU)to coordinate the implementation ofthe National Adaptation Strategy tothe EU Sugar Reform, SwazilandService Contract No 2007 / 147-446EuropeAid/125214/C/SER/SZ: Restructuring andDiversification Management Unit to coordinate theimplementation of the National Adaptation Strategy to theEU Sugar Reform, SWAZILANDEC General Budget – SU-21-0603SWAZILAND Technical Audit of Farmers AssociationN Y A N Y A L I F A R M E R S C O O P E R A T I V ESubmitted to:The Delegation of the European Commission to Swaziland4 th Floor Lilunga House, Somhlolo Road, Mbabane, SwazilandMinistry of Economic Planning and DevelopmentP.O. Box 602Mbabane H100, Swaziland

DISCLAIMERThe contents of this report are the sole responsibility of the RDMU and can in no waybe taken to reflect the view of the European Union.Nyanyali Farmers Cooperative Report - 2009Page iii

8 RECOMMENDATIONS ...................................................................................- 38 -9 CONCLUSION ................................................................................................- 41 -10 LITERATURE REFERENCES .....................................................................- 43 -11 PRODUCT INFORMATION .........................................................................- 45 -12 APPENDICES .............................................................................................- 49 -Nyanyali Farmers Cooperative Report - 2009Page v

LIST OF TABLESTABLE 1. PUMP AND MOTOR SPECIFICATIONS AND MEASUREMENTS CONDUCTED ON PUMP ...................... - 18 -TABLE 2. SPRINKLER VALUATED BLOCK SUMMARY ........................................................................................... - 25 -TABLE 2.TECHNICAL PROPERTIES OF SPRINKLERS FOUND ON SITE AT 35M OPERATING PRESSURE ................ - 26 -TABLE 4.OPTIMAL OPERATING PRESSURE VS NOZZLE DIAMETER FOR SPRINKLERS ......................................... - 28 -TABLE 5. MAINTENANCE SCHEDULE FOR SPRINKLER IRRIGATION SYSTEMS ..................................................... - 33 -TABLE 6. MAINTENANCE PRACTICES IMPLEMENTED BY NYANYALI FARMERS .................................................. - 33 -LIST OF FIGURESFIGURE 1 PUMP HOUSE NEXT TO THE MKONDO RIVER ...................................................................................... - 2 -FIGURE 2 LATERAL ISOLATION VALVES ................................................................................................................ - 3 -FIGURE 3.SAPWAT SCREEN INDICATING WATER REQUIREMENT FOR SPRINKLER IRRIGATION WITH RAINFALLTAKEN INTO ACCOUNT ................................................................................................................................ - 7 -FIGURE 4. REQUIRED RADIUS OF 90 BENDS (SOURCE: ARC (2007)) .................................................................. - 11 -FIGURE 5. 2 X 300MM X 45° BENDS ON PUMP SUCTION MANIFOLD ................................................................ - 12 -FIGURE 6. CONCENTRIC AND ECCENTRIC REDUCERS ......................................................................................... - 12 -FIGURE 7. INCORRECTLY DIMENSIONED ECCENTRIC REDUCER ......................................................................... - 13 -FIGURE 8. SPACING AND PLACING OF SUCTION PIPE INLETS............................................................................. - 14 -FIGURE 9. NYANYALI INTAKE SUMP ALONG THE CROCODILE INFESTED MKHONDVO RIVER ............................ - 14 -FIGURE 10. MINIMUM WATER DEPTH ABOVE SUCTION PIPE INLET ................................................................. - 15 -FIGURE 11. ATMOSPHERIC PRESSURE VS. HEIGHT ABOVE SEA LEVEL ............................................................... - 17 -FIGURE 12. IRON OXIDE ACCUMULATES IN THE MKHONDVO RIVER ................................................................ - 18 -FIGURE 13. INSIDE NYANYALI PUMP HOUSE ...................................................................................................... - 20 -FIGURE 15. LATERAL ISOLATION VALVES ........................................................................................................... - 26 -FIGURE 16. MEASURING APPARATUS FOR SPRINKLER NOZZLE SIZE ................................................................. - 27 -FIGURE 17. NYANYALI YIELD IN TONES CANE PER HECTARE .............................................................................. - 31 -LIST OF APPENDICESAppendix 1: SEB usage for river pump station phase 2Appendix 2: capital recovery factors (CRF)Appendix 3: soil map and block layoutAppendix 4: Farm BoundariesNyanyali Farmers Cooperative Report - 2009Page vi

ABBREVIATIONSAbbreviationAEARCASAECUCVDUEACEUFAGARHDPEMCCNARNPSHPVCRSSCSABISESSASWADEUsDescriptionApplication EfficiencyAgricultural Research CouncilAmerican Society of Agricultural EngineersChristiansen’s uniformity coefficientCoefficient of VariationDistribution Uniformity coefficientEquivalent Annual CostEmitter UniformityFarmers AssociationGross Application RateHigh Density PolyethyleneMotor Control CentreNet Application RateNet Positive Suction HeadPolyvinyl ChlorideRoyal Swaziland Sugar CorporationSouth African Irrigation InstituteSystem EfficiencySwaziland Sugar AssociationSwaziland Water & Agricultural Development EnterpriseStatistical UniformityNyanyali Farmers Cooperative Report - 2009Page vii

1 I N T R O D U C T I O NAssociation general information1. Farm name: Swazi Nation Land2. Name of Association: Nyanyali Farmers Association3. Location:LatitudeLongitudeAltitude 370Maximum Temperature 36Minimum Temperature 84. Postal address: 116 Sdvokodvo5. Contact Details:Chairman – Mr. S. NtjangaseFarm Supervisor- Mr. N. Dlamini 633 60426. Area of farm (ha) 437. Crops irrigated: Sugarcane8. Designers name and details: MENDIP9. Date of evaluation: 09 December 200910. Evaluators: Tiekie de Beer and Bongani BhembeNyanyali Farmers Cooperative Report - 2009 Page - 1 -

2 B A C K G R O U N D O N I R R I G A T I O ND E V E L O P M E N TNyanyali Farmers Cooperative Farmers association’s irrigation system of 43Ha was designedand installed by Mendipm PTY Ltd The company provided all the inputs for this draglineirrigation system.2 . 1 The p r o j e c t‣ The dragline irrigation system has a 108m lateral spacing and 18m draglines. spacing is12m. .‣ This project is supplied by the Usuthu River and the pump house was constructed alongthis river bank.Figure 1 Pump house next to the Mkondo River‣ The pump station houses one KSB ETA 80/250 pump powered by a 55kW motor.‣ This pump is equipped with a mechanical control valves, no flow meters, andmalfunctioning safety mechanisms and pressure measuring devices occur.‣ Laterals are isolated by ball valves without pressure regulation.‣ Sprinklers are not equipped with sprinkler pressure regulators.Nyanyali Farmers Cooperative Report - 2009 Page - 2 -

‣ The Motor Control Centres (MCC) is well designed and still in good working condition.Figure 2 Lateral isolation valves‣ This project was developed on only two soil sets, the W and the B soil sets. Under thesesets there are various soil sets and different irrigation regimes may be applied to differentareas of the farm.Nyanyali Farmers Cooperative Report - 2009 Page - 3 -

3 T E C H N I C A L A U D I T R E P O RT3.1.1 R E V I E W O F T H E I R R I G A T I O N D E S I G N C R I T E R I AA N D S P E C I F I C A T I O N S3.1.1.1 Irrigation Design and Specifications by the contractorDesign information from the designer and installer Mendip could not be obtained. The designwas therefore checked against Swaziland Sugar Industry Standard and SABI norms shownbelow.3.1.1.1.1 DESIGN CRITERIACropArea under irrigationGross ApplicationNet ApplicationIrrigated CycleSprinkler dischargeSprinkler SpacingPrecipitation RateStand timeAnnual Irrigation hoursSugar Cane47.6Ha52mm39 mm per cycle (6.5 mm/day)6/7 days (depending on soil type)0.39 l/s18m x 18m4.3mm/hr12 hours (depending on soil type)3 300 hours3.1.1.2 Review of Contractor Irrigation Design Criteria and Specifications3.1.1.2.1 PlanningOf the four major input of planning namely crop, climate, soil and irrigation system, the studyrevealed that crop and climate information used as supplied by the SSA (Swaziland SugarAss) Soil types were not taken into consideration during design and or implementation ofphase two of the project.Nyanyali Farmers Cooperative Report - 2009 Page - 4 -

Attached in annexes is field Map 1, a soil map of Nyanyali Farmers Cooperative FA indicatingthe two major soil sets on which the project was developed on.The purpose of this study was to determine the quantity of water required by the crops percycle during peak demand periods and how often it was to be applied taking practicaloperating practice into account.Taking soils into account the following planning schedule was developed;Peak Design-Norm For Sprinkler Irrigation At Nyanyali Investment Pty Ltd1 GENERAL INFORMATION1,1 Owner Nyanyali Investment Pty Ltd1,2 Farm Name - Number - Co-ordinates Swazi nation land1,3 Telephone number1,4 Area developed 43 Ha1,5 Water Allocation 43 l/s2 CLIMATE2,1 Month state Jan2,2 Weather station state Ubombo2,3 Evaporation mm/day 7mm A-Pan or 5mm Grass Factor3 MANAGEMENT3,1 Available working days per week days 73,2 Available working Hours per day hours 244 CROP BLOCK NO Betusile/Dundee Winn/Oakleaf4,1 Type state Sugar Sugar4,2 Area Ha 20 94,3 Plant spacing m NA NA4,4 Row spacing m 1.8 1.84,5 Effective root depth m 0.45 0.454,6 Plant time date August August5 SOIL Betusile/Dundee Winn/Oakleaf5,1 Effective soil depth m 1 15,2 Water holding capacity mm/m 140 1405,3 Easy available water (10-50 kPa) 50% mm/m 40 405,4 Easy available water in root zone mm 18 186 WATER6,1 C en S Classification of water C+S Mkondo River7 EMITTERNyanyali Farmers Cooperative Report - 2009 Page - 5 -

7,1 Type type Vyrsa 70 Vyrsa 707,2 Nozzle size mm 11/64 11/647,3 Discharge l/h 1390 13907,4 Working pressure kPa 350 3507,5 Application efficiency % 70 707,6 Emitter spacing m 18 187,7 Lateral spacing m 18 187,8 Wetted diameter m 36 367,9 Gross Application rate on wetted area mm/h 4.29 4.297,10 Nett Application rate on wetted area mm/h 3.33 3.338 SCHEDULING8,1 Crop factor (max) max 1.15 1.158,2 Evaporation mm/day 5 58,3 Evapotranspiration mm/day 5.75 5.758,4 Net Irrigation requirement mm/day 5.75 5.758,5 Gross Irrigation requirements mm/day 6.04 6.048,6 Theoretical cycle length day 7.04 7.048,7 Theoretical Stand time hour 12.16 12.168,8 Practical Cycle length day 6 68,9 Practical Stand time hours 12 128,10 Working days per week days 7 78,11 Irrigation hours per day hours 24 248,12Gross application rate per practicalcycle mm 51.48 51.488,13 Gross application per month mm 220.62 220.629 SCHEDULE OF BLOCKS THAT IRRIGATE TOGETHER10 HYDRAULICS10,1 Pressure difference over block m 40 4010,2Pressure at beginning of sub main orlateral m 40 4010,3 Velocity in mainline (max) m/s 1 1Nyanyali Farmers Cooperative Report - 2009 Page - 6 -

Climatic information:Climatic information used when compiling the above schedule was obtained from SAPWATand a summary of which is shown by the figures below.Figure 3.SAPWAT screen indicating water requirement for sprinkler irrigation withrainfall taken into accountNyanyali Farmers Cooperative Report - 2009 Page - 7 -

Soil informationSoil properties used when compiling the afore schedule was obtained from the below charts.These are the two major soils found within the farm, an outline of which is shown on a soilmap attached in annexes.Nyanyali Farmers Cooperative Report - 2009 Page - 8 -

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4 F I E L D E V A L U A T I O N O F I R R I G A T I O NS Y S T E M4.1.1 P u m p s A n d P u m p S t a t i o n s4.1.1.1 Pump Suction SideThe majority of problems occurring with pumps are usually the result of poor suction sidedesign and installation. The installation and design of the suction side must ensure thatturbulence occurring in the suction pipe and collection of air in high places in the suction pipe,is prevented. In view of the above, the different suction side components were evaluated.4.1.1.1.1 Suction Pipe Flow RateThe suction pipe flow velocity of river and booster pumps was calculated as follows:353,68 QV m / s2d……………………….… (1)Where: V = flow velocity in pipe (m/s)Q = flow rate (m³/h)d = inner diameter of suction pipe (mm).One ETA 80-250 pump is installed and the duty point inscribed on its information plate is148m³/hr flow at 80m head. pump discharge was ascertained by getting the multiply of thetotal irrigated area under cane (43 ha), industry norms of 2.57 sprinklers per hectare, 1.4m³/hrsprinkler discharge and 10% safety factor for pump discharge. The pump must, thereforegenerate at least 170.2 m³/hr of flow to meet irrigation requirements.Based on equation one above the flow velocity at the estimated pump flow through the300mm suction manifold is 0.67 m/s. According to the Agricultural Research Council, ARC(2007) the ideal suction pipe flow velocity must be 1.0 m/s, but suction pipe flow velocities upto 1.5 m/s are acceptable. A flow velocity through the suction manifold is within therecommended limits.Nyanyali Farmers Cooperative Report - 2009 Page - 10 -

4.1.1.1.2 Requirements for Fittings90º BendsThe radius (mm) of a 90º bend must be, at least, as shown in Figure 4rdFigure 4. Required radius of 90 bends (source: ARC (2007))r 2d100mm …………………………………... (2)Where: r = radius of bend (mm)d = inner diameter of suction pipe (mm).The suction manifold has two 300mm x 45° bends (figure 5) the radius of which could not bemeasured. According to figure 4 and equation 2 above, the required minimum for a 300mm x90° bend is 700mm but because the length of the suction pipe between this bend and thepump inlet manifold is more than five times the suction pipe diameter, the effects of theincorrect sizes are insignificant. The 200mm x 90° bend on the delivery main is alsoincorrectly dimensioned but have minimal effects on pump performance.Nyanyali Farmers Cooperative Report - 2009 Page - 11 -

Figure 5. 2 x 300mm x 45° bends on pump suction manifoldReducersThe inlet on the pump suction side must be eccentric with the straight side towards the top, toprevent air collecting in the suction pipe and causing cavitation (ARC, 2006). The length ofboth eccentric and concentric reducers were evaluated against equation 3 (figure 6) below,adopted from the ARC.Figure 6. Concentric and eccentric reducersNyanyali Farmers Cooperative Report - 2009 Page - 12 -

( d ) ………………………... (3)52d1Where: = length of the reducer (mm)d1 = smaller inner diameter (mm)d2 = larger inner diameter (mm)A 100-300 eccentric reducer is installed with the straight side towards the top, to prevent aircollecting in the pipe and an 80-200 concentric reducer on the delivery pipe (figure 7). Thelength of the eccentric reducer is 450mm and according to the above equation this should beat least 1000mm long. The concentric reducer is 150mm in radius, 450mm shorter than therecommended minimum calculated using equation 3 above. The unacceptable dimensions ofthe eccentric reducer affects pump performance substantially because it is directly attachedto the pump suction and the sudden restriction in size increases turbulence occurrences andcause irregular feeding of the pump hence cavitation.Figure 7. Incorrectly dimensioned eccentric reducerThe unacceptable dimensions of the concentric reducer had negligible effects on theperformance of the pump and the entire system.Nyanyali Farmers Cooperative Report - 2009 Page - 13 -

4.1.1.1.3 Suction Pipe InletsSpacing and placing of suction pipe inletsIn a well constructed sump the inlet of the suction pipe must be in accordance to therequirements of at least 0,5d (d = inner diameter of the suction pipe) from the bottom of thepump sump (figure 8) and at least 1,5d away from the side of the pump sump.1.5dd0.5dd3d 3d 1.5dFigure 8. Spacing and placing of suction pipe inletsThere is no proper intake structure instead the suction inlet (foot valve) is suspended at thebank of the Mkhondvo River (figures 9). The foot valve is not protected in any way and isintermittently in direct contact with the bottom of the channel and debris carried with the riverwater. This is not acceptable. Sand bangs are used to redirect the receding river water backinto the sump, especially when the river level drops. The sump has no provision for cleaning,in order to clean this sump one has to swim in the crocodile infested river.Figure 9. Nyanyali intake sump along the Mkhondvo RiverNyanyali Farmers Cooperative Report - 2009 Page - 14 -

The area around the foot valves was clean and the total area of the openings from the suctionsieve was more than the minimum ARC requirement of 1.5 times larger than the crosssectionalarea of the suction pipe to prevent partial blockages of the suction sieve.Occasionally sand deposits inside this suction position becomes too much such that pumpingstops for cleaning to proceed. Currently, cleaning proceeds with caution and is a danger towhosoever is cleaning the sump. There is no proper structure to facilitate cleaning areaaround foot valves.The recommended minimum water depth above suction pipe inlet depends on the suctionpipe velocity and was evaluated using the graph shown in figure 10 below. Site investigationrevealed a water depth of approximately 1400mm above the foot valve and with a maximumvelocity of 1.0m/s the depth should be approximately 0.7m. These measurements were takenafter a period of heavy rains and the river level was high. At minimum river level the waterdepth is expected to drop, the extent and the effects of this drop should further be evaluated.Figure 10. Minimum water depth above suction pipe inlet4.1.1.1.4 Suction side lossesDuring the evaluation of the pump station, attention was also given to the length of thesuction pipe and fittings that were used. Friction losses for pipes were calculated as for anyother pipe (using Hazen-Williams equation) and secondary losses for fittings were calculatedwith the aid of the following formula:Nyanyali Farmers Cooperative Report - 2009 Page - 15 -

hf6375kQ4d2………………………………….. (4)Where: hf = secondary friction loss in fitting (m)k = friction loss factor (annexure 1)Q = flow rate in the fitting (m³/h)d = inner diameter of the fitting (mm)A summation of friction loss across the non-return valve, the suction pipe, the 90° bends andthe eccentric reducer at ultimate flow gives a total hf of 0.25m. Friction in the suction pipe hasa direct effect of maximum suction height and consequently the available net positive suctionhead (NPSH) and is discussed below.4.1.1.1.5 Suction heightThe essence of this evaluation was to determine the actual static suction head of the installedpumps and then compare it to the designers suction height assumption. The maximumsuction height was calculated using equation 5 below;hs(max) hdhfhvp NPSHrequired ………………. (5)Where: hs (max) = maximum suction height (m)hdhfhvp= atmospheric pressure on terrain (m)= suction side losses (friction losses, as well as secondary losses in fittings, m= vapour pressure of water (m)NPSH required = net positive suction head from the pump curve (m)Nyanyali Farmers Cooperative Report - 2009 Page - 16 -

Figure 11. Atmospheric pressure vs. height above sea levelThe suction height was measured to be approximately 4.5 meters. The NPSH required(NPSHr) of the ETA 80-250 end suction pump is 4.3m (from attached pump curve). From theabove formula the maximum allowable suction height is therefore 4.55m and this calculationconfirms that river pumps are installed with a correct suction static height.Further analysis compared NPSH available (NPSHa) to NPSH required. The NPSHrequirements of 4.3 meters are well within the available NPSH of 4.55 meters. A safety factorof 0.5 is factored in this calculation as per manufacture’s requirement. This conforms to therecommendation of NPSHr < NPSHa (ARC, 2007) required for optimum pump performance.The difference between these two figures is too small and might be affecting pumpperformance.4.1.1.2 Pump evaluationThe essence of evaluating this pump was to determine whether the pump function asindicated by the pump curve and to ascertain, if any, design, installation and managementfaults. The performance curve of the installed pump is attached under ‘product information’below and table 1 below indicates Nyanyali Farmers irrigation pump and motor specificationsas observed from the information plate.Nyanyali Farmers Cooperative Report - 2009 Page - 17 -

Table 1. pump and motor specifications and measurements conducted on pumpPUMP SPECIFICATIONS FROM INFORMATION PLATE AND MEASUREMENTSMake / model KSB ETA 80-250Number of units 1Pump duty point148m³/hr @ 80mImpeller diameter mm 248Pressure under normal operation m -Flow under normal operation m³/hr -MOTOR SPECIFICATIONS FROM INFORMATION PLATE AND MEASUREMENTSModel and typeVEMPower (P motor) kW 55Power factor (cos ø) 0.91Motor efficiency, % 93.6Speed rpm 29604.1.1.2.1 Pump OperationThis pump was not in operation during the evaluation. The assessment was carried out aftera period of heavy rains which not only raised the river level but also conceded a lot of ironoxide. According to Nyanyali management irrigating during this time causes this material toaccumulate inside the pipelines and in the long run reduces their capacity. Pumpperformance is, also, seriously affected when operated during the time, more so, because theiron oxide changes the specific gravity of the water. This evaluation, in any case could nothave been conclusive because there is no flow meter to measure pump discharge.Figure 12. Iron oxide accumulates in the Mkhondvo RiverNyanyali Farmers Cooperative Report - 2009 Page - 18 -

4.1.1.2.2 Power required on the pump shaftPower required on the pump shaft was calculated with the following formula and establisheswhether motors were sized accurately.P g H Q36,000………………………………………. (6)Where: P = power required on the pump shaft (kW)ρ = density of water (1000 kg/m³)g = gravity acceleration (9.81 m²/s)H = pump pressure at service point (m)Q = pump delivery at service point (m³/h)η = pump efficiency at service point (%)Based on the estimated duty point shown in table 1 above the required power on the pumpshaft is a theoretical value of 42.02kW. Using a flow of 170m³/hr (system capacityrequirement) instead of the 148m³/hr increases the required power to 47.4kW. According theARC the power output of the motor must be 10-15% greater than the power required on thepump shaft and corresponds to 46.2kW and 52.1kW respectively. In both scenarios the55kW motor that drives this pump is correctly specified. These results will only be conclusiveafter accurately determining system pressure requirement. There is a possibility that the 80mindicated on the pump is too high which would mean using a smaller motor.The required power, Prequired, of this pump was to be compared with the output power of theelectric motor obtained from measurements of voltage and current. The pump was not inoperation. According to the ARC the configuration of the different power units must conformto the expression Pu = P < Pmotor.4.1.1.2.3 Pump Station General Evaluation‣ The pump station is well constructed. It was designed and constructed for at least twopump but currently only one pump is installed. There is ample working space, goodventilation and all lights are working.Nyanyali Farmers Cooperative Report - 2009 Page - 19 -

Figure 13. Inside Nyanyali pump house‣ There is no flow measuring device‣ There is no pump and motor safety mechanism‣ Pump control valves are mechanical and require maintenance‣ The MCC is incomplete, there is no voltmeter, hour meter, etc‣ The pump house is used as a storeroom; there is poor hygiene and ineffective floordrainage system.Pump AlignmentThe alignment of the pump and the motor was also evaluated. This was done by placing theedge of a straight steel ruler over the coupling flanges at four points, 90º apart. This straightedge rested equally on all points on the flanges to ensure parallel alignment. The distancebetween the coupling levels at 90º intervals was also measured. A Vernier calliper was used.Measurements were the same on all the points, and on all pumps and that meant the unitwas squarely aligned.Nyanyali Farmers Cooperative Report - 2009 Page - 20 -

4.1.2 P o w e r S u p p l y A n d C o n s u m p t i o nPower consumptionA basic economic analysis was undertaken to ascertain the trade-off between capital andenergy costs. For this economic analysis the Equivalent Annual Cost method (EAC) wasused. The EAC adjusts the costs of items to a stream of equal amounts of payment overspecified periods (equivalent annual costs) in order to enable comparison.Items costed were:‣ Infield irrigation (tape and fittings including flusher lines and valves - considered aspolythene). Including installation costs.‣ Distribution system - pipelines (main lines and submains - considered as PVC).Including installation costs.‣ Pumping plant (including pump control valves, flow meters, electrical components,motors etc). Included installation costs. Where no new pumps were included, all andany supplementary equipment/operations connected with pumping e.g. upgrades,new impellors, new switchgear, new valves were included‣ Primary filter station (only filters and associated pipework, valves etc).Excluded were:‣ All existing infrastructure (e.g. AC pipe, balancing dam, MCC housing, etc)‣ Buildings (e.g. cluster houses, pump stations, filter station structure)‣ Valves external to pump stations and filter stations.‣ Irrigation controller systems‣ Fertigation systemsThe operational costs for the schemes were confined to energy costs and maintenance(excluded labour. Admin etc).Interest rate: 10%Useful life(thisanalysis)Infield 10 yearsirrigation(Tape etc):PVC/Poly 20 yearsNyanyali Farmers Cooperative Report - 2009 Page - 21 -

pipe:Filters:Pumpingequipmentand electrics15 years15 yearsMaintenanceInfield 3%irrigation:Distribution - 2%pipelines:Pumping 1%plant:Filters: 3%CapitalRecoveryRate (CRF)factors:Volume waterapplied perhectare:SEB tariff –Consumption:Maximumdemand:Efficiency ofpumpingplant(See attached table)9000mI\3/ha/annum0.22 E/kWh69.42 E/kVaCalculate at design duty pointNyanyali Farmers Cooperative Report - 2009 Page - 22 -

EAC COMPUTATION MATRIXThese costs have been calculated only for Phase Two of theProjectITEM COST ITEM Main Bid1 Infield irrigationCapital cost (E) -Useful life (years) 10Annual maintenance (%) 3EAC of infield irrigation (E) -2 Distribution systemCapital cost (E) -Useful life (years) 20Annual maintenance (%) 2EAC of Distribution system (E) -3 Pumping plantCapital cost (E) -Useful life (years) 15Annual maintenance (%) 1EAC of Pumping plant (E) -4 FiltersCapital cost (E) -Useful life (years) 15Annual maintenance (%) 3EAC of Filters (E) -5 Annual Energy Cost (E) 111,466.06Total EAC (E) -Energy cost as a % of total EAC#DIV/0!For sprinkler irrigation a 40% EAC value is accepted. A higher and a lower figure indicatesover design and under design respectivelyNyanyali Farmers Cooperative Report - 2009 Page - 23 -

4.1.3 S u p p l y S y s t e mThe evaluation of the supply system is discussed under the following headings;4.1.3.1 Mainline sizeSABI norm suggests that for raising main lines with a diameter of 200mm or smaller amaximum of 1.5m friction fore ach 100 m pipe length (1.5%) is allowed (ARC, 2003).Mainlines with pipe sizes greater than 200mm are evaluated by determining the mosteconomical pipe diameter; capital and annual cost for different pipe diameters werecompared and the following equation is used;dkQWhere: di = inside diameter of pipe, mmK= constant derived from annual irrigation hoursQ= flow rate (m 3 /h)0.37i …..……………………….……… (8)No information was available on irrigation layout and pipe sizes and class. An undisputedconclusion, however, on whether the supply system was correctly designed or not can not bedrawn until precise details on pipe size, pipe classes, and distances occupied by the differentsizes are obtained. Accurate details are required also on the maximum area available forfuture development and a hydraulic check conducted thereafter.4.1.3.2 Mainline classFor the same reason as above, this evaluation could not identify as to whether the mainlineclasses were correctly designed or not. Pipe bursts are one major indicator of underspecificationin pipe classes and none were experienced on mainlines except for a fewidentified sections just after the pump house.Nyanyali Farmers Cooperative Report - 2009 Page - 24 -

5 F I E L D E V A L U A T I O N O F S P R I N K L E R I R R I G A T I O NS Y S T E MTable 2. Sprinkler valuated block summaryBlock Area (ha) 43Type of sprinkler systemDraglineName of DesignerMENDIPName of contractorMENDIPDesignMeasuredSprinkler spacing (m x m) 18 17-19Lateral spacing (m) 108 107-110Stand pipe height (m) 3 3Pressure regulator - NoDragline diameter (mm) 20 20Dragline length (m) - 50 – 100A complete system evaluation could not be conducted because the irrigation system was shutdown. The assessment was carried out after a period of heavy rains which not only raised theriver level but also conceded a lot of iron oxide. According to Nyanyali management irrigatingduring this time causes this material to accumulate inside the pipelines and in the long runreduces pipeline capacity. Pump performance is, also, seriously affected when operatedduring the time, more so, because the iron oxide changes the specific gravity of the water. Itis strongly recommended to conduct the distribution and delivery tests to determine defects, ifany, in the design and installation of the infields.Hydraulic ValvesLaterals of this dragline irrigation system are connected to the mainline through mechanicalvalves (figure 14). For better performance of the system hydraulic valves must be installedinstead and equipped with pressure-regulating pilots.The installation of hydraulic valves equipped with pressure regulating pilots reduces a higherinlet pressure to a lower constant outlet pressure, regardless of fluctuating flow rates and orvarying inlet pressure. The pilot would sense down-stream pressure and modulates open orclose, causing the main valve to throttle, thus maintaining constant delivery pressure.Nyanyali Farmers Cooperative Report - 2009 Page - 25 -

When down –stream pressure falls below the pilot setting, the pilot and main valve wouldmodulate open to increase pressure and maintain pilot setting. When downstream pressurerises above the pilot setting, the pilot and main valve would throttle close to decreasepressure and maintains pilot setting. The pilot has an adjusting screw to preset the desiredpressure.Figure 14. Lateral isolation valvesTechnical Properties of Sprinklers Found On Site:The effects of different nozzles/emitters and different sprinkler packages observed in thisproject were evaluated by identifying the response of the different emitters when subjected tothe same amount of pressure, all other factors equal. Table 3 below indicates the propertiesof the different sprinkler packages found on site when subjected to 35m sprinklerrecommended operating pressure.Table 3.Technical properties of sprinklers found on site at 35m operating pressureSprinkler Package Nozzle size Discharge (m³/hr) Wetted Radius (m)Rain bird 14070 1/8" nozzle 3.18 0.74 12.6Rain bird 14070 11/64" nozzle 4.37 1.39 15.2VYRSA 70 4.4mm nozzle 4.37 1.36 15.9Minimum Discharge (m 3 /hr) 0.74Maximum Discharge (m 3 /hr) 1.39Average Discharge (m 3 /hr) 1.16Flow variation (%) 55.87Nyanyali Farmers Cooperative Report - 2009 Page - 26 -

Two sprinkler packages with two different nozzle size combinations were identified as shownin table 3 above. Flow variation due to the different sprinkler – nozzle combinations is 55.87%and is not in line with the ARC recommendation stating that the difference in discharge in aspecific irrigation block may not vary by more than 10% from the average discharge. Theaverage application rate of the above combination is 1.16m³/hr and is lower than the designapplication of 1.4m³/hr. These figures indicate that even on highly efficient pumping andsupply system, irrigation efficiency will not improve, at least not until uniformity in this regardis obtained. This different combination has an effect also on the wetting diameter due to theirdifferent body trajectory angles.Nozzle wearingMeasurements of the amount of sprinkler nozzle wear (mm) averaged 1.4% reaching amaximum of 2.1%. An increase of 5% in nozzle area means a 10% increase in flow andpower demand, which means additional operating costs and over-irrigation. The ARCtherefore recommends sprinkler replacement if wear is greater than 5%. This irrigationsystem has been operated for only 7 years.Sprinkler nozzles were measured with a specially machined apparatus (Figure 14)Figure 15. Measuring apparatus for sprinkler nozzle sizeNyanyali Farmers Cooperative Report - 2009 Page - 27 -

5.1.1 S p r i n k l e r p r e s s u r eThe optimal operating pressure (kPa) of the sprinkler should be between 60 and 70 times thenozzle diameter (mm). This is applicable to nozzles of 3 to 7 mm diameter (ARC, 2006).Table 4.Optimal Operating Pressure Vs Nozzle Diameter for SprinklersNozzle diameterOperating pressure (kPa)Mm Inches x 60 x 701,591 / 16 "1,985 / 64 "2,383 / 32 "2,787 / 64 "3,181 / 8 " 191 2223,579 / 64 " 214 2503,975 / 32 " 238 2784,3711 / 64 " 262 3064,763 / 16 " 286 3335,1613 / 64 " 310 3615,5615 / 64 " 333 3895,9515 / 64 " 357 4276,351 / 4 " 381 445Based on the results of table 3 and accordance to these norms the optimum sprinkleroperating pressure in this scheme ranges from 191kPa – 306kPa. Pressure variation is thusan unacceptable 46.9%. Pressure variation in a specific block should not be more than 20%the average operating pressure. One type/size nozzle must be used.Hydraulics design error:The laterals in this project are connected to an average of 6 sprinklers per lateral. These areconnected every second hydromatic along the 50mm HDPE lateral. However, some lateralshave up to 12 sprinklers run concurrently which increases friction losses to beyond therecommended 20% pressure variation.This irrigation system does not have scour valves; dirt is trapped inside the pipe networks,especially on hydromatics subsequently reducing sprinkler flow and pressure. Nozzle wearingis hastened as well.Nyanyali Farmers Cooperative Report - 2009 Page - 28 -

Possible ways of improving the hydraulic variation include the installation of pressureregulating device (installing hydraulic valves) repair and/or removal of pinched lateral/submainlines and the redesign of the hydraulic system.Sprinkler pressure regulators:The project was implemented on an uneven topography and this directly effect sprinkleroperating pressure. When flow is downhill pressure is gained and the reverse is true.Sprinkler pressure regulators were installed by the contractor but were later removed onsome sprinklers by management. Some pressure regulators are damaged/brake when thesprinkler falls.LeaksTimely maintenance and repair of minor leaks are often neglected in this system. The leaks inthe pipes of the supply network of this irrigation system caused a drop in operating pressureand an increase in pump flow. This increase in pump duty reduces the efficiency at which thepump operates, causing further pressure and delivery reductions. A drop in the operatingpressure causes a change in the performance of sprinkler. Mainly, these leaks are observedin sprinklers, sprinkler stand-dragline connections, broken dragline, pipelets, hydromatics,sub-mains, mainline, etc. it is important that all leaks are located quickly and repaired. A leakprevention program should include regular replacement of damaged draglines.Gross application rate (GAR)The gross application rate (GAR) of the sprinkler was thereafter calculated, by means of thefollowing formula;GAR qe1000A ....…………………………………. (10) mm/hWhere; GAR = Gross Application RateA = wetted area (m 2 )The GAR is a fraction of emitter discharge and sprinkler spacing as indicated by equation 10above. The nozzle sizes found in this development (table 3) has an average GAR of3.6mm/hr and is lower than the recommended GAR for sugarcane of 4.2mm/hr.Nyanyali Farmers Cooperative Report - 2009 Page - 29 -

6 A S S E S S M E N T O F O P E R A T I O N , M A N A G E M E N TA N D M A I N T E N A N C E O F T H E I R R I G A T I O NS Y S T E M6 . 1 O p e r a t i o nAs-built drawings and design information not availableThe fact that no design or installation information is available consigns a huge constraint onmanagement. Forward planning on aspects related to the irrigation infrastructure cannot bedone, i.e. replacement stock purchase; item like pipes, fittings, etc are procured afterbreakages because the details of that particular pipe, fitting, etc is obtained from the brokenpart. This increases their down time and negatively impacts on crop production.Operation and maintenance manual not availableThe different components forming the irrigation system require different operating proceduresand these are obtained from an operation and maintenance manual. This document, like allother documents, is not available and for efficient performance of these components, it mustbe compiled. The consequence of not having this document is seen during this evaluation inthat incorrect sequences are followed in opening and closing the pump. Also, this documenthelps in the formulation of a maintenance plan and provides guidelines to be followed duringmaintenance.Financial viability for smallholder growerThe late conclusion of loan agreements (seasonal loans) results in the late delivery of inputsand late application of fertilizers and chemicals, which reduces yields and sucrose content,resulting in reduced financial returns per hectare and inability to recoup invested capital. Inaddition, the absence of any dividends for distribution to farming association members at theend of each season can lead to a decline in the cohesion of farmers’ associations/cooperatives,a cohesion which is essential to increasing on-farm efficiency.Yields records for only three production season were found and the highest being 104.7tones per hectare (figure16).Nyanyali Farmers Cooperative Report - 2009 Page - 30 -

Figure 16. Nyanyali yield in tones cane per hectareInterest RatesIt can be argued that even relatively large reductions in interest rates have not had anysignificant impact on the sustainability of this sector. The sector appears to have deterioratedto one of a sustained financial crisis. This, therefore, calls for an integrated programme ofaction, to look at:‣ Discounted tariffs with regards to bank charges, including administration fees.‣ A re-look at the repayment period with regard to capital loans, with a view to having itextended from the current 7 years to at least 10 yearsConsidering the reduction of interest rates on all loans to a level not exceeding 12% perannum, such measures would allow smallholder growers to realize some return on theirinvestment and to be able to eventually pay dividends to the investing members. Alternativelyother financial arrangements can be put in place without any prejudice to the commercialoperations of the financial institutions currently engaged with the sector (SSA, 2008).ElectricityEnergy costs are too high. During dry periods the pumps run continuously for 24 hours perday and 6 days a week, there is a need to have the tariffs looked at and, maybe have thetariff rate discounted for sugar cane growers to enable them to be sustainable in thebusiness. It is imperative to train the farm manager and/or pump attendants on when and howmany pumps to start at a time as this affect electricity maximum demand.Appendix three shows a calculation of the amount of energy used by this FA and compares itto what should have been used per season. This maximum demand calculation gives anNyanyali Farmers Cooperative Report - 2009 Page - 31 -

indication of the amount small growers spend on electricity and how much could have beensaved when pumps are operated correctly.Production CostsSugar prices are on a continual downward spiral whereas production costs have taken theopposite direction, so that if no immediate plan of action is formulated to address theproblem, most smallholder growers will slowly but surely perish. Fertilizers, herbicides, farminputs, labour costs are making it difficult for the farmers to use the best farming practices.Maybe a solution to that could also be a consortium that can be formed for the sugarcanegrowing industry to have a muscle where buying of farm inputs is concerned (SSA, 2008).Transport costsThis is by far the greatest challenge faced by Nyanyali, a large chunk of sugarcane revenuegoes to the transporters and growers feel that there is a need to address this issue and lookat ways to improve the current situation. they are not only far form the mill but the nonperformance of transport operators leads to a heavy loss in cane quality which also leads to aserious financial loss to the growers. The issue of mill distance from the farm is, in a numberof instances, of major concern. The mere construction of a bridge (s) across a stream(s)would go a long way towards reducing these distances and, consequently, the attachingcosts.MillersSmallholder cane growers feel that millers also have a significant role to play in assistingsmallholder growers technically, financially and otherwise. Bulk purchasing comes to mindhere as the millers are endowed with the financial muscle (economies of scale) which couldresult in discounted input prices for growers (SSA, 2008).6 . 2 Man a g e m e n t P r a c t i c e sSchedulingEffective scheduling ensures that the correct amount of water is applied at the right time andthe correct place. As a scheduling method Nyanyali Farmers Association use the give andtake method. This method utilizes long term evaporation means and rainfall is accountedthrough rain gauge readings. Two 8 hour shifts are made per day starting at 6am to 2pm then2pm to 10pm again. The net irrigation application could not be accurately determinedbecause delivery and distribution tests were not conducted. However, based on collectedNyanyali Farmers Cooperative Report - 2009 Page - 32 -

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 -

‣ Pump discharge is controlled mechanically by a butterfly valve. There is no Bermadhydraulic valve and the pump/motor has no safety mechanism e.g. no-flow switch.‣ The pump house is used as a storeroom and thus reduces working space and ventilationis compromised.‣ Only one pumping unit is installed operating 24/7. When this pump brakes sugarcanestands for weeks without water. This pump unit is occasionally serviced, especially at theend of the season; otherwise management attends only to breakages.MAIN LINE‣ No information was available on irrigation layout and pipe sizes and class. An undisputedconclusion, however, on whether the supply system was correctly designed or not can notbe drawn until precise details on pipe size, pipe classes, and distances occupied by thedifferent sizes are obtained. Accurate details are required also on the maximum areaavailable for future development and a hydraulic check conducted thereafter.‣ Mainline isolation valves are insufficient and some of those that are there aremalfunctioning‣ The main irrigation pipe works does not have enough air valves and those that are thereare leaking – overall system efficiency compromisedSPRINKLER INFIELD IRRIGATION‣ A complete system evaluation could not be conducted because the irrigation system wasshut down. The assessment was carried out after a period of heavy rains which not onlyraised the river level but also conceded a lot of iron oxide. According to Nyanyalimanagement irrigating during this time causes this material to accumulate inside thepipelines and in the long run reduces pipeline capacity.‣ Laterals of this dragline irrigation system are connected to the mainline through amechanical valve. For better performance of the system hydraulic valves must beinstalled instead and equipped with pressure-regulating pilots.‣ Two sprinkler packages with two different nozzle size combinations were identified and theflow variation due to the different sprinkler – nozzle combinations is 55.87%. this is not inline with the ARC recommendation stating that the difference in discharge in a specificirrigation block may not vary by more than 10% from the average discharge. The averageapplication rate of the above combination is 1.16m³/hr and is lower than the designapplication of 1.4m³/hr. This different combination has an effect also on the wettingdiameter due to their different body trajectory angles.Nyanyali Farmers Cooperative Report - 2009 Page - 35 -

‣ The optimum sprinkler operating pressure in this scheme ranges from 191kPa – 306kPa.Pressure variation is thus an unacceptable 46.9%. Pressure variation in a specific blockshould not be more than 20% the average operating pressure.‣ Measurements of the amount of sprinkler nozzle wear (mm) averaged 1.4% reaching amaximum of 2.1%. An increase of 5% in nozzle area means a 10% increase in flow andpower demand, which means additional operating costs and over-irrigation.‣ The laterals in this project are connected to an average of 6 sprinklers per lateral. Theseare connected every second hydromatic along the 50mm HDPE lateral. However, somelaterals have up to 12 sprinklers run concurrently which increases friction losses tobeyond the recommended 20% pressure variation.‣ This irrigation system does not have scour valves; dirt is trapped inside the pipe networks,especially on hydromatics subsequently reducing sprinkler flow and pressure. Nozzlewearing is hastened as well.‣ Sprinkler pressure regulators were not installed and in view of the undulating terrain theseare a necessity.‣ Timely maintenance and repair of minor leaks are often neglected in this system. Theleaks in the pipes of the supply network of this irrigation system caused a drop inoperating pressure and an increase in pump flow. This increase in pump duty reduces theefficiency at which the pump operates, causing further pressure and delivery‣ The nozzle sizes found in this development has an average GAR of 3.6 mm/hr and islower than the recommended GAR for sugarcane of 4.2mm/hr.‣ No drainage was planed with the development of this project and large waterlogged areasappeared at some areas.OVERALL MANAGEMENT AND MAINTENANCEManagement and maintenance‣ Old, broken and stolen equipment affects the efficiency of managing this irrigationsystem. This equipment includes mechanical valves, hydromatics, draglines, sprinklerstands, sprinkler and nozzles, etc.‣ Without an operation and maintenance manual, management have difficulty in operatingand maintaining the system. Incorrect operation procedures are followed and impropermaintenance schedules adopted.‣ No scheduling measurements were followed and under the current irrigation pattern theirrigation system can not meet sugarcane irrigation requirement.Nyanyali Farmers Cooperative Report - 2009 Page - 36 -

‣ Farmers do not have the required expertise on irrigation matters and end up makingexpensive mistakes.‣ Areas that require drainage are difficult to manage‣ The different soil series on which the project is developed has different water holdingproperties and require different irrigation patterns. These are difficult to manage.Operations‣ The late conclusion of loan agreements (seasonal loans) results in the late delivery ofinputs and late application of fertilizers and chemicals, which reduces yields and sucrosecontent, resulting in reduced financial returns per hectare and inability to recoup investedcapital‣ It can be argued that even relatively large reductions in interest rates have not had anysignificant impact on the sustainability of this sector. The sector appears to havedeteriorated to one of a sustained financial crisis.‣ Electricity bill for Nyanyali Farmers Association pump is too high.‣ High Transport costs: A large chunk of sugarcane revenue goes to the transporters andgrowers feel that there is a need to address this issue and look at ways to improve thecurrent situation.‣ High Production Costs: Sugar prices are on a continual downward spiral whereasproduction costs have taken the opposite direction‣ The highest yield received by Nyanyali is 104.7 t/ha and was in 2008. There has been asteady increase in productivity over the yearsNyanyali Farmers Cooperative Report - 2009 Page - 37 -

8 R E C O M M E N D A T I O N STo evaluate the constraints of the project properly we have decided to categorised therecommendations in four categories namelyA. Immediately: This has to been done direct after harvesting.B. Short term: This has to been done this seasonC. Medium term: This has to been done before replantD. Long term: This has to be rectified with replant.PUMP STATIONImmediately:‣ Rehabilitate pump stations, i.e. install pressure and flow meters, improve pump housesdrainage systems, etc E 50 000.00‣ Do routine maintenance on pump and all electrical equipment. E 20 000.00‣ Establish arrangement with a reputable establishment to assist with the maintenance ofall equipment.‣ Accurately determine system pressure requirements and check if the installed 55kW 2-Pole motor is of the correct size.Medium term:‣ Replace all incorrectly dimensioned fittings on the suction and delivery manifold with thecorrect size E 15 000.00‣ Improve pump and motor safety mechanisms E 10 000.00Long term:‣ Design and construct new sump E 150 000.00MAIN DISTRIBUTION LINEImmediately:‣ Check mainline hydraulics and produce irrigation layout map indicating pipe sizes andclass E 20 000.00‣ Fix all leaking mainlines, air valves and control valves. E 2 500.00Nyanyali Farmers Cooperative Report - 2009 Page - 38 -

‣ Install additional air valves, scour valves etc E 15 000.00‣ Do routine maintenance on all equipment. E 2 500.00INFIELD IRRIGATIONImmediately:‣ Fix all damaged sprinkler stands and replace leaking draglines and other malfunctioningequipment E 30 000.00‣ Install identical sprinklers with identical nozzle sizes and of the acceptable dischargeE 5 000.00‣ Install hydraulic valves in every lateral hydrant assembly E10 000.00Medium term:‣ Equip all sprinklers with pressure regulators. E 5 000.00‣ Correct all hydraulic design faults in infields E 50 000.00Long term:‣ Replant the areas that perform badly E 70 000.00‣ Abandon soils with a poor potential, and plant alternative crops‣ Install sub-surface and surface drainOVERALL MANAGEMENT AND MAINTENANCEOperations‣ The biggest challenge faced by nyanyali is high transportation cost. Big Bend mill is morethan 100km from this FA. Restructuring and diversification as an alternative will needfinancial support, especially now that the financier is threatening to terminate funding thisunviable enterprise.‣ Considering the reduction or termination of interest rates on all loans, such measureswould allow smallholder growers to realize some return on their investment and to be ableto eventually pay dividends to the investing members. Alternatively other financialarrangements can be put in place without any prejudice to the commercial operations ofthe financial institutions currently engaged with the sector.‣ There is a need to have the electricity tariffs looked at and, maybe have the tariff ratediscounted for sugar cane growers to enable them to be sustainable in the business.Pump attendance must be trained on economic ways of operating pumps.Nyanyali Farmers Cooperative Report - 2009 Page - 39 -

‣ A consortium could be formed for the sugarcane growing industry to have a muscle wherebuying of farm inputs is concerned. This could reduce production costsManagement‣ Compilation of an operation and maintenance manual to assist in the implementation of aproper maintenance and operation strategies for the association.‣ A proper scheduling tool must be adopted and, where possible, blocks scheduledaccording to soil type.‣ Establish arrangement with a reliable establishment to assist with the maintenance of allequipment.‣ Replace all old, damage and stolen equipment‣ Strengthen training of FA on operation and maintenance and monitoring and evaluation ofirrigation system‣ Implement an irrigation pattern that will result into a 6.5 mm/ day in all blocks.Nyanyali Farmers Cooperative Report - 2009 Page - 40 -

9 C O N C L U S I O NPump StationNyanyali’s ETA 80-250 pump is driven by a 55 kW 2-Pole motor designed to handle the 43hectares under sugarcane. There is no intake structure instead the 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 the riverwater. 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 55kW motor that drives this pump is correctly specified. These results will only beconclusive after accurately determining system pressure requirement. There is a possibilitythat the 80m indicated on the pump information plate is too correcting this could result inusing a smaller motor.The evaluation of pumps could not identify whether the pumps are optimally operating or notbecause the pump was not in operation during the evaluation. The assessment was carriedout after a period of heavy rains which not only raised the river level but also conceded a lotof iron oxide. According to Nyanyali management irrigating during this time causes thismaterial to accumulate inside the pipelines and in the long run reduces their capacity. Pumpperformance is, also, seriously affected when operated during the time, more so, because theiron oxide changes the specific gravity of the water. This evaluation, in any case could nothave been conclusive because there is no flow meter to measure pump discharge.This FA will require at least E95 000.00 to attend to immediate and short termrecommendations which include getting all pumps running to full capacity, replacing allincorrectly dimensioned fittings (bends and reducers) on the suction and delivery manifoldwith the correct size, etc. an intake sump will have to be constructed at a cost of E150000.00.Main Distribution LineNo information was available on irrigation layout and pipe sizes and class and an undisputedconclusion on whether the supply system was correctly designed or not cannot be drawn untildetails on pipe size, pipe classes, and distances occupied by the different sizes are obtained.Nyanyali Farmers Cooperative Report - 2009 Page - 41 -

Accurate details are required also on the maximum area available for future development anda hydraulic check conducted thereafter.Infield Sprinkler IrrigationLaterals of this dragline irrigation system are connected to the mainline through a mechanicalvalve. For better performance of the system hydraulic valves must be installed instead andequipped with pressure-regulating pilots. The laterals in this project are connected to anaverage of 6 sprinklers per lateral. These are connected every second hydromatic along the50mm HDPE lateral. However, some laterals have up to 12 sprinklers run concurrently whichincreases friction losses to beyond the recommended 20% pressure variation.Two sprinkler packages with two different nozzle size combinations were identified and theflow variation due to the different sprinkler – nozzle combinations is 55.87%. This is not in linewith the ARC recommendation stating that the difference in discharge in a specific irrigationblock may not vary by more than 10% from the average discharge. The average applicationrate of the above combination is 1.16m³/hr and is lower than the design application of1.4m³/hr. This different combination has an effect also on the wetting diameter due to theirdifferent body trajectory angles. The optimum sprinkler operating pressure in this schemeranges from 191kPa – 306kPa. Pressure variation is thus an unacceptable 46.9%.Management:The biggest challenge faced by Nyanyali is high transportation cost. Big Bend mill is morethan 100km from this FA. Restructuring and diversification as an alternative will needfinancial support, especially now that the financier is threatening to terminate funding thisunviable enterprise. Performance of this irrigation scheme is affected, to some extend, by alack and/or late application for fertilisers, herbicides, high interest rates, and high electricitycost.Apart from these problems, operation, management and maintenance of this scheme ischaracterised by insufficient water applied to the crop, no irrigation scheduling, lack of anoperation and maintenance manual, insufficient training on different components of system,old and worn-out equipment, drainage problem and frequent breakages of pump anddraglines.Nyanyali Farmers Cooperative Report - 2009 Page - 42 -

10 L I T E R A T U R E R E F E R E N C E S1. ARC- Institute for Agricultural Engineering,1998. In-field Evaluations of thePerformance of two Types of Irrigation Emitters executed on behalf of the waterResearch Commission. Water Research Commission, Republic of South Africa.2. ASAE Standards. 1997. Field evaluation of micro-irrigation systems, ASAE EP458.3. ASAE Standards. 1998. Design and installation of micro-irrigation systems, ASAE EP405.14. Burt, C.M. & Styles S.W. 1994. Drip and micro-irrigation for Trees, Vines, and RowCrops. Irrigation Training and Research Centre (ITRC). USA.5. Keller, J, and Bliesner, RD. 1990. Set Sprinkler Uniformity and Efficiency Sprinkle andTrickle Irrigation. Chapman and Hall, New York.6. Koegelenberg, F. H. & others. 1996. Irrigation Design Manual. Agricultural ResearchCouncil - Institute for Agricultural Engineering. RSA.7. Koegelenberg, F. H. 2002. Norms for the design of irrigation systems. AgriculturalResearch Council - Institute for Agricultural Engineering. RSA.8. Reinders, F.B. 1986. Evaluation of irrigation systems. Directorate of AgriculturalEngineering and Water provision. RSA.9. Reinders, F.B. 1996. Irrigation Systems: Evaluation and Maintenance. SA Irrigation,Vol. 5-7.10. Scott, K. 1997. Designing with Sprinklers. Unpublished literature. ARC- institute ForAgricultural Engineering. Silverton, Republic of South Africa.11. Scott, K. 1998. The effects of wind in sprinkler irrigation. ARC- Institute for AgriculturalEngineering. Republic of South Africa.Nyanyali Farmers Cooperative Report - 2009 Page - 43 -

12. Solomon K.H. 1988a, Irrigation Systems and Water Application Efficiencies. Centrefor Irrigation Technology, California State University, Fresno, California.13. Solomon K.H. 1988b.A new way to view Sprinkler pattern, Center for irrigationTechnology, California State University, Fresno, California.14. Solomon, K.H. 1990. Sprinkler Irrigation Uniformity, center for irrigation Technology,California State University, Fresno,California.15. Solomon, KH Zoldoske, DF and Oliphant, JC. 1996. Laser Optical Measurement ofSprinkler Droplet Sizes. Center for irrigation Technology, California State University,Fresno, California.16. SSA.2001. Sugar Production Manual. Swaziland Sugar Association. Mbabane17. SSA.2008. www.ssa.co.sz18. Zoldoske, D.F. and Solomon, K.H. 1988. Coefficient of Uniformity- What it tells us.Center for irrigation Technology, California State University, Fresno, California.Nyanyali Farmers Cooperative Report - 2009 Page - 44 -

11 P R O D U C T I N F O R M A T I O NRiver pumps technical details;Sprinkler equipmentNyanyali Farmers Cooperative Report - 2009 Page - 45 -

Nyanyali Farmers Cooperative Report - 2009 Page - 46 -

Soils classification according to SSANyanyali Farmers Cooperative Report - 2009 Page - 47 -

Nyanyali Farmers Cooperative Report - 2009 Page - 48 -

12 A P P E N D I C E SAttached are the following documentsAppendix 1: SEB usage for pumpsAppendix 2: capital recovery factors (CRF)Appendix 3: soil map and block layoutAppendix 4: Farm BoundariesNyanyali Farmers Cooperative Report - 2009 Page - 49 -

SEB usage for River pump station Phase2Annual WaterWater requirement use 14000m³/Year 43 Total water use in year 602000 m³/YearMonths Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Des% use per month 8.1 7.7 9.88 9.09 8.79 4.96 2.86 5.43 9.18 11.5 11.95 10.56Watter use per monthmain 48762 4635459477.6 54721.8 52915.8 29859.2 17217.2 32688.6 55263.6 69230 71939 63571.2Water use per hour 68 64 83 76 73 41 24 45 77 96 100 88Main pumps Needed 0.5 0.5 0.6 0.5 0.5 0.3 0.2 0.3 0.5 0.7 0.7 0.6River Pumps practical 1 1 1 1 1 1 1 1 1 1 1 1kW use for Main Pump 43 43 43 43 43 43 43 43 43 43 43 43Total kVa Demand 86 86 86 86 86 86 86 86 86 86 86 86Total kw use for themonth14662.713938.617884.916454.8115911.748978.641 5177.29829.43916617.7320817.41321632.0119115.82Total Max. Demandcosts5970.125970.125970.12 5970.12 5970.12 5970.12 5970.12 5970.12 5970.12 5970.12 5970.12 5970.12Total kW cost3225.793066.503934.67 3620.06 3500.58 1975.30 1138.98 2162.48 3655.90 4579.83 4759.04 4205.48Total Energy Cost /month9195.919036.629904.799590.1789470.7047945.4217109.1048132.597 9626.0210549.95110729.16 10175.6111466.1Nyanyali Farmers Cooperative Report - 2009 Page - 50 -

CAPITAL RECOVERY FACTORS (CRF)Interest RatesYears% 2 3 4 5 6 7 8 9 10 15 205 0.538 0.367 0.282 0.231 0.197 0.173 0.155 0.141 0.130 0.096 0.0806 0.545 0.374 0.289 0.237 0.203 0.179 0.161 0.147 0.136 0.103 0.0877 0.553 0.381 0.295 0.244 0.210 0.186 0.167 0.153 0.142 0.110 0.0948 0.561 0.388 0.302 0.250 0.216 0.192 0.174 0.160 0.149 0.117 0.1029 0.568 0.395 0.309 0.257 0.223 0.199 0.181 0.167 0.156 0.124 0.11010 0.576 0.402 0.315 0.264 0.230 0.205 0.187 0.174 0.163 0.131 0.11711 0.584 0.409 0.322 0.271 0.236 0.212 0.194 0.181 0.170 0.139 0.12612 0.592 0.416 0.329 0.277 0.243 0.219 0.201 0.188 0.177 0.147 0.13413 0.599 0.424 0.336 0.284 0.250 0.226 0.208 0.195 0.184 0.155 0.14214 0.607 0.431 0.343 0.291 0.257 0.233 0.216 0.202 0.192 0.163 0.15115 0.615 0.438 0.350 0.298 0.264 0.240 0.223 0.210 0.199 0.171 0.160Nyanyali Farmers Cooperative Report - 2009 Page - 51 -

Nyanyali Farmers Cooperative Report - 2009 Page - 52 -

Nyanyali Farmers Cooperative Report - 2009 Page - 53 -