Service Contract No 2007 / 147-446 MABHUDLWENI ... - 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 AssociationM A B H U D L W E N I F A R M E R S L I M I T E DSubmitted 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

Your contact personswith GFA Consulting Group GmbH areDr. Susanne PecherAnke SchnoorRestructuring and Diversification Management Unit(RDMU)to coordinate the implementation of the National AdaptationStrategy to the EU Sugar Reform, SwazilandTechnical Audit of Farmers AssociationAuthors: Tiekie de Beer,Designer Member of the South African IrrigationInstitute (SABI)&Bongani BhembeMission ReportAddressGFA Consulting Group GmbHEulenkrugstraße 82D-22359 HamburgGermanyPhone +49 (40) 6 03 06 – 111Fax +49 (40) 6 03 06 - 119Email: afrika@gfa-group.deMabhudlweni Farmers Limited Report - 2009Page ii

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.Mabhudlweni Farmers Limited Report - 2009Page iii

TABLE OF CONTENTSMABHUDLWENI FARMERS LIMITED ....................................................................................................... iTABLE OF CONTENTS ................................................................................................................................. ivLIST OF TABLES ............................................................................................................................................. vLIST OF FIGURES ........................................................................................................................................... vLIST OF APPENDICES .................................................................................................................................. viABBREVIATIONS ......................................................................................................................................... viii1 INTRODUCTION ............................................................................................... - 1 -2 BACKGROUND ON IRRIGATION DEVELOPMENT ....................................... - 2 -The project was developed in two phases the firs was 11 Ha in and the second 13.7 Ha in 2003 ..........- 2 -The project ..........................................................................................................................................................- 2 -3 TECHNICAL AUDIT REPORT .......................................................................... - 4 -3.1.1 REVIEW OF THE IRRIGATION DESIGN CRITERIA AND SPECIFICATIONS .........................- 4 -3.1.1.1 Irrigation Design and Specifications by the contractor ..............................................................- 4 -3.1.1.1.1 DESIGN CRITERIA ............................................................................................................- 4 -3.1.1.2 Review of Contractor Irrigation Design Criteria and Specifications .........................................- 4 -3.1.1.2.1 Planning ................................................................................................................................- 4 -4 FIELD EVALUATION OF IRRIGATION SYSTEM ..........................................- 10 -4.1.1 Pumps And Pump Stations ...............................................................................................................- 10 -4.1.1.1 Pump Suction Side ...................................................................................................................- 10 -4.1.1.1.1 Suction Pipe Flow Rate .......................................................................................................- 10 -4.1.1.1.2 Requirements for Fittings ...................................................................................................- 11 -4.1.1.1.3 Suction Pipe Inlets ..............................................................................................................- 13 -4.1.1.1.4 Suction side losses ..............................................................................................................- 15 -4.1.1.1.5 Suction height .....................................................................................................................- 16 -4.1.1.2 Pump evaluation .......................................................................................................................- 17 -4.1.1.2.1 Pump Operation ..................................................................................................................- 18 -4.1.1.2.2 Power required on the pump shaft ......................................................................................- 18 -4.1.1.2.3 Pump Station General Evaluation .......................................................................................- 19 -4.1.2 Power Supply And Consumption .....................................................................................................- 20 -4.1.3 Supply System ..................................................................................................................................- 23 -4.1.3.1 Mainline size ............................................................................................................................- 23 -4.1.3.2 Mainline class ..........................................................................................................................- 23 -4.1.4 System capacity evaluation ...............................................................................................................- 24 -5 FIELD EVALUATION OF SPRINKLER IRRIGATION SYSTEM .................... - 26 -5.1.1 Sprinkler pressure .............................................................................................................................- 29 -6 ASSESSMENT OF OPERATION, MANAGEMENT AND MAINTENANCE OFTHE IRRIGATION SYSTEM .................................................................................. - 32 -6.1 Operation .............................................................................................................................................- 32 -6.2 Management Practices ........................................................................................................................- 34 -6.3 Maintenance Survey ...........................................................................................................................- 35 -Mabhudlweni Farmers Limited Report - 2009Page iv

7 CONSTRAINTS TO EFFICIENT SYSTEM PERFORMANCE ........................- 36 -8 RECOMMENDATIONS ...................................................................................- 41 -9 CONCLUSION ................................................................................................- 44 -10 LITERATURE REFERENCES .....................................................................- 46 -11 PRODUCT INFORMATION .........................................................................- 48 -12 APPENDICES .............................................................................................- 53 -LIST OF TABLESTABLE 1. PUMP AND MOTOR SPECIFICATIONS AND MEASUREMENTS CONDUCTED ON PUMP ...................... - 17 -TABLE 2.TECHNICAL PROPERTIES OF SPRINKLERS FOUND ON SITE AT 35M OPERATING PRESSURE ................ - 28 -TABLE 3.OPTIMAL OPERATING PRESSURE VS NOZZLE DIAMETER FOR SPRINKLERS ......................................... - 29 -TABLE 4. MAINTENANCE SCHEDULE FOR SPRINKLER IRRIGATION SYSTEMS ..................................................... - 35 -TABLE 5. MAINTENANCE PRACTICES IMPLEMENTED BY MABHUDLWENI FARMERS LIMITED .......................... - 35 -LIST OF FIGURESFIGURE 1. MABHUDLWENI FARMERS LIMITED PUMP STATION ALONG THE USUTHU RIVER ............................. - 2 -FIGURE 2. MCC ..................................................................................................................................................... - 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. 200MM 90° BEND ON 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. MABHUDLWENI SUCTION POSITION ................................................................................................. - 14 -FIGURE 10. MINIMUM WATER DEPTH ABOVE SUCTION PIPE INLET ................................................................. - 15 -FIGURE 11. ATMOSPHERIC PRESSURE VS. HEIGHT ABOVE SEA LEVEL ............................................................... - 16 -FIGURE 12. LEAK ON THE SUCTION PIPE ............................................................................................................ - 19 -FIGURE 13. INSIDE MABHUDLWENI PUMP HOUSE ............................................................................................ - 19 -FIGURE 14. PHASE TWO MAINLINE ISOLATION VALVE ...................................................................................... - 27 -FIGURE 15. MEASURING APPARATUS FOR SPRINKLER NOZZLE SIZE ................................................................. - 29 -Mabhudlweni Farmers Limited Report - 2009Page v

LIST OF APPENDICESAppendix 1: SEB usage for river pump station phase 2Appendix 2: capital recovery factors (CRF)Appendix 3: soil map and block layoutMabhudlweni Farmers Limited 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 UniformityMabhudlweni Farmers Limited 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: Mabhudlweni Farmers Limited3. Location:Latitude 2 953 579.00Longitude 68 645.00Altitude 180Maximum Temperature 36Minimum Temperature 84. Postal address: 105 Siphofaneni5. Contact Details:Chairman – Mr. Mfanzile Maziya 623 8867Farm Supervisor-6. Area of farm (ha) 24.757. Crops irrigated: Sugarcane8. Designers name and details: Siza Construction9. Date of evaluation: 13 September 200910. Evaluators: Tiekie de Beer and Bongani BhembeMabhudlweni Farmers Limited 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 TMabhudlweni Farmers Limited Farmers association’s irrigation system of 24,75 Ha wasdesigned and installed by Siza Construction in 1998. Siza Construction provided all theinputs for this dragline irrigation system.The project was developed in two phases the firs was 11 Ha in and the second 13.7 Ha in2003T h e p r o j e c t‣ The dragline irrigation system has a 97m lateral spacing and 18m draglines.‣ Water to this project is supplied by the Usuthu River and the pump house was constructedalong the river bank.Figure 1. Mabhudlweni Farmers Limited pump station along the Usuthu River‣ The pump station houses one KSB ETA 80/250 pump powered by a 45kW motor. Thispumping unit was installed in 1998 and has been replaced several times.‣ This pump is equipped with a mechanical butterfly control valves, no flow meters, andmalfunctioning safety mechanisms and pressure measuring devices are installed.Mabhudlweni Farmers Limited Report - 2009 Page - 2 -

‣ Laterals are isolated by a brass valves.‣ Sprinklers are not equipped with sprinkler pressure regulators.‣ The Motor Control Centres (MCC) is in a bad working condition.Figure 2. MCC‣ This project was developed on only two soil series, the Cuba and the Winn soil series.Mabhudlweni Farmers Limited 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 Siza Construction could not be obtained.The design was therefore checked against Swaziland Sugar Industry Standard and SABInorms shown below.3.1.1.1.1 DESIGN CRITERIACropArea under irrigationGross ApplicationNet ApplicationIrrigated CycleSprinkler dischargeSprinkler SpacingPrecipitation RateStand timeAnnual Irrigation hoursSugar Cane24.75Ha52mm39 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.Mabhudlweni Farmers Limited Report - 2009 Page - 4 -

Attached in annexes is field Map 1, a soil map of Mabhudlweni Farmers Limited 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 Mabhudlweni Irrigation Scheme1 GENERAL INFORMATION1,1 Owner Mabhudlweni Irrigation Scheme1,2 Farm Name - Number - Co-ordinates Swazi nation land1,3 Telephone number1,4 Area developed 24.75 Ha1,5 Water Allocation 24.75 l/s2 CLIMATE2,1 Month state Jan2,2 Weather station state Mhlume2,3 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 Cuba/Inhouk 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 Cuba Winn/Oakleaf5,1 Effective soil depth m 1 15,2 Water holding capacity mm/m 180 1405,3 Easy available water (10-50 kPa) 50% mm/m 90 405,4 Easy available water in root zone mm 40.5 186 WATER6,1 C en S Classification of water C+S Komati RiverMabhudlweni Farmers Limited Report - 2009 Page - 5 -

7 EMITTER7,1 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 3.138,7 Theoretical Stand time hour 12.16 5.408,8 Practical Cycle length day 6 38,9 Practical Stand time hours 12 68,10 Working days per week days 7 78,11 Irrigation hours per day hours 24 248,12 Gross application rate per practical cycle mm 51.48 25.748,13 Gross application per month mm 220.62 257.409 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 1Mabhudlweni Farmers Limited 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 accountSoil 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.Mabhudlweni Farmers Limited Report - 2009 Page - 7 -

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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 ps 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).The pump’s design duty point could not be ascertained and for the purposes of the evaluationpump discharge was estimated by getting the multiply of the total irrigated area (24.75 ha),industry norms of 2.57 sprinklers per hectare, 1.4m³/hr sprinkler discharge and 10% safetyfactor for pump discharge. The pump must therefore generate at least 98m³/hr of flow to meetirrigation requirements. If this design was based on 1.8m³/hr emitter discharge and 7.5 daysirrigation cycle, just like all Siza Construction designs, pump duty increasing to 100.8m³/hr.Based on equation one above the flow velocity at the estimated pump flow through the250mm suction manifold is 0.55 m/s and 0.57 m/s for the two scenarios respectively.According to the Agricultural Research Council, ARC (2007) the ideal suction pipe flowvelocity must be 1.0 m/s, but suction pipe flow velocities up to 1.5 m/s are acceptable.Flow velocities through the suction manifolds are within the recommended limit.Mabhudlweni Farmers Limited 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 2rdFigure 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).There is only one 200mm 90° bend on the delivery side of the pump (figure 5). According tofigure 4 and equation 2 above, the required minimum is 500mm not 200mm which is theradius of these bends. These bends have minimal effects on pump performance.Mabhudlweni Farmers Limited Report - 2009 Page - 11 -

Figure 5. 200mm 90° bend on 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 4) below,adopted from the ARC.Figure 6. Concentric and eccentric reducersMabhudlweni Farmers Limited Report - 2009 Page - 12 -

( d ) ………………………... (3)52d1Where: = length of the reducer (mm)d1 = smaller inner diameter (mm)d2 = larger inner diameter (mm)A 100-250 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 18). Thelength of the eccentric reducer is 550mm and according to the above equation this should beat least 750mm long. The unacceptable dimensions of this reducer affects pump performancesubstantially because it is directly attached to the pump and the sudden restriction in sizeincreases turbulence occurrences and cause irregular feeding of the pump hence cavitation.Figure 7. Incorrectly dimensioned eccentric reducerThe concentric reducer is 150mm long and according to equation 3 this should be at least600mm. The unacceptable dimensions of the concentric reducer had negligible effects on theperformance of the pump and the entire system.4.1.1.1.3 Suction Pipe InletsSpacing and placing of suction pipe inletsMabhudlweni Farmers Limited Report - 2009 Page - 13 -

In 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 6) 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 inletsThe suction inlets are approximately 150m from the pump house and are installed on thebanks of the Usuthu River without a proper intake sump. A diversion channel was constructeddiverting water from the river into the two foot valves. At this new suction position the footvalve is not protected in any way and is intermittently in direct contact with the bottom of theriver bed and debris carried with the river water. This is not acceptable. Also during the dryseason, sand bags are used to redirect the receding Usuthu River back into the suctionposition and create suction depth.Figure 9. Mabhudlweni suction positionMabhudlweni Farmers Limited Report - 2009 Page - 14 -

The minimum water depth above the suction pipe inlet depends on the suction pipe velocityand was evaluated using the graph shown in figure 34 below. Site investigation revealed awater depth of approximately 0.25m and with a maximum velocity of 0.6m/s the water depthabove the suction inlet should be at least 0.5m. The water depth is expected to drop duringthe dry season exacerbating this glitch. The effects of the shallow depth on the pumps arereflected through vortex and pump cavitation which significantly reduces pump efficiency andperformance. During this assessment the pump was not in operation to recognize theseeffects.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: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)Mabhudlweni Farmers Limited Report - 2009 Page - 15 -

A summation of friction loss across the non-return valves, the 130m long suction pipe and theeccentric reducer at ultimate flow gives a total hf of 0.55m. Friction in the suction pipe has adirect 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)hd = atmospheric pressure on terrain (m)hf = suction side losses (friction losses, as well as secondary losses in fittings, mhvp = vapour pressure of water (m)NPSH required = net positive suction head from the pump curve (m)Figure 11. Atmospheric pressure vs. height above sea levelMabhudlweni Farmers Limited Report - 2009 Page - 16 -

The suction height was measured to be approximately 2 meters. The NPSH required(NPSHr) of the ETA 80-250 end suction pump is 3.5m (from attached pump curve). From theabove formula the maximum allowable suction height is therefore 5.55m 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 3.5 meters are well within the available NPSH of 6.55 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.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 Mabhudlweni Farmers Association irrigation pump andmotor specifications as observed from the information plate.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 point100.8m³/hr @ 80mImpeller diameter mm F/S 259Pressure under normal operation m -Flow under normal operation m³/hr -MOTOR SPECIFICATIONS FROM INFORMATION PLATE AND MEASUREMENTSModel and typeWegPower (P motor) kW 45Power factor (cos ø) 0.89Motor efficiency, % 94Speed rpm 2950Mabhudlweni Farmers Limited Report - 2009 Page - 17 -

4.1.1.2.1 Pump OperationThe pump was not in operation and this evaluation could not be executed. During theassessment sugarcane was on dry-off hence some components of the system were beingserviced. This evaluation, in any case could not have been conclusive because the onlypressure gauge in the pump delivery pipe is not working and there is no flow meter tomeasure pump discharge.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 31.39kW. According the ARC the power output of the motormust be 10-15% greater than the power required on the pump shaft and corresponds to36.1kW. Under this consideration, the 45kW motor driving this pump is over-specified. A37kW 2-Pole motor should have been installed. It is worth noting that the above duty point isoutside the recommended operating range of the 80-250 pump, a smaller 65-250 pump wasused for pump efficiency calculations.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.Mabhudlweni Farmers Limited Report - 2009 Page - 18 -

4.1.1.2.3 Pump Station General Evaluation‣ The access ladder into this pump house is too steep and does not have hand rails. this isnot safeFigure 12. Leak on the suction pipe‣ The pump house walls are falling apart and could collapse anytime‣ This pump station is remote but not well secured, used as a storeroom hencecompromising ventilation, and it is unhygienic.Figure 13. Inside Mabhudlweni pump houseMabhudlweni Farmers Limited Report - 2009 Page - 19 -

‣ There is no proper floor drainage structure; a plan was made to drain the water out of thepump house.‣ There is no flow measuring device, and unsatisfactory pump and motor safety mechanism‣ Pump control valves are mechanical and require maintenance‣ There is no guard cover over pump and motor coupling‣ The MCC is incomplete, there is no voltmeter, hour meter, etcPump 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.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).Mabhudlweni Farmers Limited Report - 2009 Page - 20 -

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 yearspipe:Filters: 15 yearsPumping 15 yearsequipmentand electricsMaintenanceInfield 3%irrigation:Distribution - 2%pipelines:Pumping 1%plant:Filters: 3%CapitalRecoveryRate (CRF)factors:Volume waterapplied perhectare:SEB tariff –Consumption:Maximum(See attached table)9000mI\3/ha/annum0.22 E/kWh69.42 E/kVaMabhudlweni Farmers Limited Report - 2009 Page - 21 -

demand: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) 95,501.59Total EAC (E) -Energy cost as a % of total EACFor sprinkler irrigation a 40% EAC value is accepted. A higher and a lower figure indicatesover design and under design respectivelyMabhudlweni Farmers Limited Report - 2009 Page - 22 -

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.Mabhudlweni Farmers Limited Report - 2009 Page - 23 -

4.1.4 S y s t e m c a p a c i t y e v a l u a t i o n‣ This irrigation system was installed in two phases and is 24.75 hectare dragline irrigationsystem. The first phase was 21.35 ha and the second phase was 3.4 ha which came withthe addition of Mr. Mfelani Dlamini to Mabhudlweni FA.‣ At the heart of this irrigation project is an ETA 80-250 pump driven by a 2-Pole 45kWmotor. this pumping unit extract water from the Usuthu river‣ The design duty point for this pump is not known but the current developed requires atleast 98m³/hr pump flow to meet sugarcane irrigation requirements. At this flow rate theinstalled pump can generate a maximum of 90m head at full size impellor, 63.5%efficiency and 37.9kW absorbed power.‣ Mabhudlweni FA system pressure requirements were calculated by summing theunderlined parameters;The sprinkler operating head (35) + riser height (3m)The pump suction head (2m)Elevation change from pump house to critical sprinkler (20m)Friction loss in the mainline and lateral (15m)Secondary head losses (5m)System pressure requirements are at 84m (inclusive of 5% safety for pump head) and areoutside the recommended operating range of the 45kW driven ETA 80-250 2-Pole pump. Asmaller and more efficient (at this duty point) 65-250 pump should have been installed anddriven by a 37kW motor instead.‣ The recommended ETA 65-250 high speed pump could be driven by a 37kW 2-Pole motorand would operate at 32kW absorbed power, 70.4% efficiency and 255mm impellordiameter.‣ Based from previous designs by Siza Construction for this area (Siphofaneni) the designcriteria normally indicates a 1.8m³/h emitter discharge with a 10 hour irrigation stand timeand 7.5 day cycle. This criterion could be altered to conform to the 1.4m³/hr qe, 12 hourTs and 6 days Tc thus slightly reducing system flow.Mabhudlweni Farmers Limited Report - 2009 Page - 24 -

‣ This irrigation system is supplied by a pump house positioned on the banks of the UsuthuRiver. Before these changes are implemented in this pump station consultations withSWADE regarding the construction of a balancing dam adjacent this FA must be made.This dam will be recharge by the newly constructed lubovane dam and the hydraulics ofthis irrigation system would be modified thereof.‣ 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.Mabhudlweni Farmers Limited Report - 2009 Page - 25 -

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 MType of sprinkler systemName of DesignerName of contractorDragline Irrigation SystemSiza ConstructionSiza ConstructionDesignMeasuredEmitter spacing (m x m) 18 18-19Lateral spacing (m) 18 85-97Stand pipe height (m) 3 3Pressure regulator No NoDragline diameter (mm) 20 20Dragline length (m) 36 50A complete evaluation of the infields could not be carried out because the system was shutdown for harvesting. All sprinkler equipment has been removed from the fields beforeburning the sugarcane. It is strongly recommended to conduct the distribution and deliverytests after harvesting to determine defects, if any, in the design and installation of the infields.The following observations were made on the system;Hydraulic ValvesLaterals of this dragline irrigation system are connected directly to the mainline withoutisolation and or hydraulic valves. This is not good irrigation installation because lateralsespecially hydromatics are characterised by frequent breakages thus the entire system mustbe shut down to attend to that snag. Only two mainline mechanical isolation valves wereidentified one of which controls Mfelani Dlamini Block (phase two).For better performance of the system hydraulic valve must be installed instead and equippedwith pressure-regulating pilots. The installation of this unit (on the valve head) reduces ahigher inlet pressure to a lower constant outlet pressure, regardless of fluctuating flow ratesand or varying inlet pressure. The pilot would sense down-stream pressure and modulatesopen or close, causing the main valve to throttle, thus maintaining constant delivery pressure.Mabhudlweni Farmers Limited Report - 2009 Page - 26 -

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. Phase two mainline isolation valveTechnical 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.Mabhudlweni Farmers Limited Report - 2009 Page - 27 -

Table 2.Technical properties of sprinklers found on site at 35m operating pressureSprinkler Package Nozzle size (mm) Discharge (m3/hr) Wetted Radius (m)Rain bird 14070 3/16" nozzle 4.78 1.65 15.8Rain-15 4mm 4.0 1.13 13.5Naan 233 2.5 x 4.4 mm DN 2.5 x 4.4 1.56 15.0Minimum Discharge (m 3 /hr) 1.13Maximum Discharge (m 3 /hr) 1.65Average Discharge (m 3 /hr) 1.45Flow variation (%) 35.94Three different sprinkler packages with three different nozzle sizes were identified as shownin table 3 above. Flow variation due to the different sprinkler – nozzle combinations (emittervariation) is 35.94% and is higher than the ARC recommendation stating that the difference indischarge in a specific irrigation block may not vary by more than 10% from the averagedischarge. The average application rate of the above combination is 1.45m³/hr and is abovethe design application of 1.4m³/hr. This figure indicates that even on highly efficient pumpingand supply system, irrigation efficiency will not improve, at least not until uniformity in thisregard is obtained. This different combination has an effect also on the wetting diameter dueto their different body trajectory angles.Nozzle wearingMeasurements of the amount of sprinkler nozzle wear (mm) averaged 2.7% reaching amaximum of 4.8%. 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% and in this projectthis exercise is almost due. Nozzle wearing is hastened, amongst others, by the age of theirrigation system (12 years), no scour valves, improper operation and maintenanceschedules, etc.Sprinkler nozzles were measured after the system was switched off with a specially machinedapparatus (Figure 14).Mabhudlweni Farmers Limited Report - 2009 Page - 28 -

Figure 15. Measuring apparatus for sprinkler nozzle size5.1.1 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 3.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 445Mabhudlweni Farmers Limited Report - 2009 Page - 29 -

Based on the results of table 3 (different nozzle sizes identified on site) and accordance tothese norms the optimum sprinkler operating pressure in this scheme ranges from 238kPa –333kPa. Pressure variation is thus an unacceptable 27.15%. Pressure variation in a specificblock should not be more than 20% the average operating pressure. One type/size nozzlemust be used.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. Leaks on the supplynetwork of this irrigation system were reported caused a drop in operating pressure and anincrease in pump flow. This increase in pump duty reduces the efficiency at which the pumpoperates, causing further pressure and delivery reductions. A drop in the operating pressurecauses a change in the performance of sprinkler. Mainly, these leaks are observed insprinklers, sprinkler stand-dragline connections, broken dragline, pipelets, hydromatics, submains,mainline, etc. it is important that all leaks are located quickly and repaired. A leakprevention program should include regular replacement of damaged draglines.Old AgeThe irrigation system was installed in1997, over 12 years ago, and as years elapsed, systemefficiency reduces due to equipment wearing out. As a matter of urgency some equipmentmust be replaced and the rest maintained for optimal performance. Draglines have morethan the allowed tolerance of three joints and sprinkler equipment, due to old age, hasbecome a nuisance. These and other equipment has to be replaced.Gross application rate (GAR)The gross application rate (GAR) of the sprinkler was thereafter calculated, by means of thefollowing formula;Mabhudlweni Farmers Limited Report - 2009 Page - 30 -

GARqe1000Amm/h....…………………………………. (10)Where; 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 three nozzle sizes found in this development (table 3) has a GAR of 5.09, 3.49and 4.81 mm/hr respectively. the recommended GAR for sugarcane is 4.2mm/hr. GAR canbe improved by ensuring that sprinklers operate at the recommended pressure/discharge,ensuring a lateral x emitter spacing of 18m x 18m, attending to leakages, ensuring the correctnumber of sprinklers operate simultaneously, using identical nozzle sizes of acceptableemitter discharge and uniform sprinkler packages.Mabhudlweni Farmers Limited Report - 2009 Page - 31 -

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.Interest 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:Mabhudlweni Farmers Limited Report - 2009 Page - 32 -

‣ 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 anindication of the amount small growers spend on electricity and how much could have beensaved when pumps are operated correctly. Currently total kilowatt available to Mabhudlweniis 1.8kW/ha which is higher than the thump suck rule of 1.5kW/ha. Reducing the motor size to37kW will drop this figure to 1.49kW/ha.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 costsSmallholder growers feel transporters have established a gold mine at the expense ofgrowers. A large chunk of sugarcane revenue goes to the transporters and growers feel thatthere is a need to address this issue and look at ways to improve the current situation. TheMabhudlweni Farmers Limited Report - 2009 Page - 33 -

non performance of transport operators leads to a heavy loss in cane quality which also leadsto a serious financial loss to the growers. The issue of mill distance from the farm is, in anumber of instances, of major concern. The mere construction of a bridge (s) across astream(s) would go a long way towards reducing these distances and, consequently, theattaching costs.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 M a n 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 Mabhudlweni Farmers Limited uses the hand feelmethod. When irrigating Mabhudlweni Farmers Limited management implemented thefollowing irrigation patterns.Given:12 hours every 7 daysThus: 12 Standing time (hours)7 Cycle length (days)Already calculated: Xg = 4.47 mmThus: hours x Xg every 7 daysThus: 53.6 mm 7 daysGross mm per day = 7.7 mm/dayThus: Net mm per day = 5.78 mm/dayThe 12 hours irrigation stand time and 7 days cycle with the observed emitter dischargerevealed a net application averaging 5.78mm/day. The recommended daily net application forsugarcane is 6.5mm. Mabhudlweni FA is therefore under-irrigating.Mabhudlweni Farmers Limited Report - 2009 Page - 34 -

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 4. Maintenance schedule for sprinkler irrigation systemsInspect the system for leakagesMonitor With each cycle AnnuallyCheck system pressure and system flowService air valves and hydrantsCheck sprinklers for wear and replace springs, washers andnozzles where necessaryFlush mainlines -XXXXTable 5. Maintenance practices implemented by Mabhudlweni Farmers LimitedMonitor 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 UnacceptableMabhudlweni Farmers Limited Report - 2009 Page - 35 -

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:‣ The suction inlets are approximately 150m from the pump house and are installed on thebanks of the Usuthu River without a proper intake sump. A diversion channel wasconstructed diverting water from the river into the two foot valves. At this new suctionposition the foot valve is not protected in any way and is intermittently in direct contactwith the bottom of the river bed and debris carried with the river water. This is notacceptable.‣ During the dry season the river level drops and the sand accumulate along the banksimpede water from reaching the intake sump. Sand bags are therefore used to redirectwater from the centre of the river into the suction point.‣ Incorrectly sized fittings in suction and delivery manifolds affect system performance. Theeffects of these are severe on the eccentric reducer because it is directly attached to thepump and the sudden restriction in size increases turbulence occurrences and causeirregular feeding of the pump hence cavitation. With such an installation wearing andmaintenance cost of the pump will increase.‣ The water depth above suction inlets is below the recommended minimum, and isexpected to further decrease during the dry season. Under this condition air is sucked inwith irrigation water and cavitates the pump. The effects of the shallow depth on thepumps are reflected through vortex and pump cavitation. This significantly reduced pumpefficiency and performance.‣ The pump was not in operation and this evaluation could not be executed. The entire24.75 hectares was on dry-off and some components of the system were being serviced.This evaluation, in any case could not have been conclusive because the only pressuregauge in the pump delivery pipe is not working and there is no flow meter to measurepump discharge.‣ The design duty point for this pump is not known but the current developed requires atleast 98m³/hr pump flow to meet sugarcane irrigation requirements. At this flow rate theinstalled pump can generate a maximum of 90m head at full size impellor, 63.5%efficiency and 37.9kW absorbed power.Mabhudlweni Farmers Limited Report - 2009 Page - 36 -

‣ System pressure requirements were calculated at 84m (inclusive of 5% safety for pumphead) and are outside the recommended operating range of the 45kW motor driven ETA80-250 2-Pole pump. A smaller and more efficient (at this duty point) 65-250 pump shouldhave been installed and driven by a 37kW motor instead.‣ One high speed pump is installed in the river pump station, and during the dry season thispump run 24 hours seven day a week hence develop recurrent mechanical and electricalfaults. Maintenance and repair cost of this pumping unit are very high.‣ 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 evaluation of pumps could not identify whether the pumps are optimally operating ornot because it was not running.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 aremalfunctioningSPRINKLER INFIELD IRRIGATION‣ A complete evaluation of the infields could not be carried out because the system was shutdown for harvesting. All sprinkler equipment has been removed from the fields beforeburning the sugarcane. It is strongly recommended to conduct the distribution anddelivery tests after harvesting to determine defects, if any, in the design and installation ofthe infields.‣ This irrigation system was installed in two phases and is 24.75 hectare dragline irrigationsystem. The first phase was 21.35 ha and the second phase was 3.4 ha which came withthe addition of Mr. Mfelani Dlamini to Mabhudlweni FA.‣ Laterals of this dragline irrigation system are connected directly to the mainline withoutisolation and or hydraulic valves. This is not good irrigation installation because lateralsespecially hydromatics are characterised by frequent breakages thus the entire systemmust be shut down to attend to that snag. Only two mainline mechanical isolation valveswere identified one of which controls Mfelani Dlamini Block (phase two). For betterMabhudlweni Farmers Limited Report - 2009 Page - 37 -

performance these hydraulic valves must be installed instead and equipped with apressure-regulating pilot.‣ Based from previous designs by Siza Construction for this area (Siphofaneni) the designcriteria normally indicates a 1.8m³/h emitter discharge with a 10 hour irrigation stand timeand 7.5 day cycle. This criterion could be altered to conform to the 1.4m³/hr qe, 12 hourTs and 6 days Tc thus slightly reducing system flow.‣ The dragline irrigation development has a design lateral spacing of 90m and 36mdraglines. Site measurements revealed a lateral spacing of at most 89-104m and 30 -50m dragline length.‣ Sugarcane requires at least 6.5mm/day and the implemented irrigation pattern combinedwith high emitter discharge variation results to only 5.9mm applied and available tosugarcane per day. Mabhudlweni is, therefore, by far under-irrigating.‣ Three different sprinkler packages with three different nozzle sizes were identified. Flowvariation due to the different sprinkler – nozzle combinations (emitter variation) is 35.94%and is higher than the recommended 10% from the average discharge. The averageapplication rate of the above combination is 1.45m³/hr and is above the design applicationof 1.4m³/hr. The different sprinkler packages have an effect, also on the wetting diameterdue to the different body trajectory angle and nozzle size has an effect flow.‣ Measurements of the amount of sprinkler nozzle wear (mm) averaged 2.7% reaching amaximum of 4.8%. An increase of 5% in nozzle area means a 10% increase in flow andpower demand, which means additional operating costs and over-irrigation.‣ The three nozzle sizes found in this development (table 3) has a GAR of 5.09, 3.49 and4.81 mm/hr respectively. the recommended GAR for sugarcane is 4.2mm/hr‣ The infield could not be evaluated because its pump was not running. The system is shutdown for harvesting.‣ The first phase of the irrigation system was installed over 12 years ago, and as yearselapsed, the system efficiency reduces due to equipment wearing out. As a matter ofurgency some equipment must be replaced and the rest maintained for optimalperformance.‣ No drainage was planed with the development of this project and large waterlogged areasappeared at some areas.‣ Some sprinklers are not equipped with pressure regulators‣ Timely maintenance and repair of minor leaks are often neglected in this systemMabhudlweni Farmers Limited Report - 2009 Page - 38 -

OVERALL MANAGEMENT AND MAINTENANCEOperations‣ 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‣ The highest yield received by Mabhudlweni Farmers Limited is 134.5 t/ha and was in2008. There has been a steady increase in productivity.‣ 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 Mabhudlweni Farmers Limited pump are 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 directionManagement and maintenance‣ Most equipment has been stolen and/or vandalised. This includes hydraulic valves,hydromatics, sprinkler stands, sprinkler and nozzles. These need to be replaced ormaintained.‣ 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.‣ The different soil series on which the project is developed has different water holdingproperties and require different irrigation patterns. These are difficult to manage.‣ Farmers do not have the required expertise on irrigation matters and end up makingexpensive mistakes.‣ The frequent mechanical and electrical faults on pump place a huge constraint onmanagement.‣ Areas that require drainage are difficult to manageMabhudlweni Farmers Limited Report - 2009 Page - 39 -

‣ Old equipment reduces efficiency of system. This equipment includes hydromatics,draglines, tripod stands, sprinkler and nozzles. The most economic decision would be toreplace this equipment instead of maintenance.Mabhudlweni Farmers Limited Report - 2009 Page - 40 -

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 namelyTo 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 STATIONNOTE: This irrigation system is supplied by a pump house positioned on the banks of theUsuthu River. Before these changes are implemented in this pump station consultations withSWADE regarding the construction of a balancing dam adjacent this FA must be made, thehydraulics of this irrigation system would be modified thereof.Immediately:‣ Reduce pumping unit capacity E105 000.00‣ Rehabilitate pump station i.e. construction of erosion control structures, improve pumpdrainage, reduce slope of access ladder and install hand rails, attend to pump housewalls etc E50 000.00‣ Establish arrangement with a reputable establishment to assist with the maintenance ofall equipment.Short term:‣ Replace all incorrectly dimensioned fittings (bends and reducers) on the suction anddelivery manifold with the correct size E 10 000.00‣ Install flow and pressure measuring devices E 70 000.00‣ Improve pump and motor safety mechanisms E 10 000.00Long term:‣ Construct proper intake sump E150 000.00Mabhudlweni Farmers Limited Report - 2009 Page - 41 -

MAIN 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 2 500.00‣ Install additional air valves, isolation valves and scour valves E 10 000.00Long term:‣ Correct any hydraulic faults in mainline in consideration of the possible changes thatmight be implemented upon completion of the balancing dams E 80 000.00SEMI-PERMANENT INFIELD IRRIGATIONImmediately:‣ Fix all damaged sprinkler stands and replace leaking draglines and other malfunctioningequipment E 10 000.00‣ Install identical sprinklers with identical nozzle sizes and of the acceptable dischargeE 5 000.00‣ Install hydraulic valves in every lateral E 20 000.00‣ Equip all sprinklers with pressure regulators. E 10 000.00Long term:‣ Correct all hydraulic design faults in infields E 50 000.00‣ Replant all blocks containing old sugarcane and low yielding varieties E 20 000.00‣ Abandon soils with poor potential, and plant alternative crops‣ Install sub-surface and surface drainOVERALL MANAGEMENT AND MAINTENANCEOperations‣ 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.Mabhudlweni Farmers Limited Report - 2009 Page - 42 -

‣ 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.‣ 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.‣ Implement an irrigation pattern that will result into a 6.5 mm/ day in all blocks.‣ Establish arrangement with a reliable establishment to assist with the maintenance of allequipment.‣ Replace all old equipment‣ Strengthen training of FA on operation and maintenance and monitoring and evaluation ofirrigation systemMabhudlweni Farmers Limited Report - 2009 Page - 43 -

9 C O N C L U S I O NMabhudlweni Farmers Limited irrigation system was installed in two phases in 1997 and 2003respectively. The first phase was 21.45ha and the second phase was 3.4 hectares both ofwhich are dragline irrigation system.Pump StationThis irrigation system is supplied by the Usuthu River and a high speed KSB ETA 80-250 endsuction pump extracts water on the bank on this river. This pump is driven by a 2-Pole 45 kWpump the design duty point of which is not known but the current developed requires at least98m³/hr pump flow to meet sugarcane irrigation requirements. At this flow rate this pump cangenerate a maximum of 90m head at full size impellor, 63.5% efficiency and 37.9kWabsorbed power.System pressure requirements were calculated at 84m (inclusive of 5% safety for pumphead) and are outside the recommended operating range of the 45kW motor driven ETA 80-250 2-Pole pump. A smaller and more efficient (at this duty point) 65-250 pump should havebeen installed and driven by a 37kW motor instead.This FA will require at least E245 000.00 to attend to immediate and short termrecommendations which include installing a new pumping unit, replacing all incorrectlydimensioned fittings (bends and reducers) on the suction and delivery manifold with thecorrect size, rehabilitating pump station, etc. However, Before these changes areimplemented in this pump station consultations with SWADE regarding the construction of abalancing dam adjacent this FA must be made, the hydraulics of this irrigation system wouldbe modified thereof.Main Distribution LineNo 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.Mabhudlweni Farmers Limited Report - 2009 Page - 44 -

Infield Sprinkler IrrigationA complete evaluation of the infields could not be carried out because the system was shutdown for harvesting. All sprinkler equipment has been removed from the fields and storedsafely in Mabhudlweni compound. It is strongly recommended to conduct the distribution anddelivery tests after harvesting to determine defects, if any, in the design and installation of theinfields.Laterals of this dragline irrigation system are connected directly to the mainline withoutisolation and or hydraulic valves. This is not good irrigation installation because lateralsespecially hydromatics are characterised by frequent breakages thus the entire system mustbe shut down to attend to that snag. Only two mainline mechanical isolation valves wereidentified one of which controls Mfelani Dlamini Block (phase two). For better performancethese hydraulic valves must be installed instead and equipped with a pressure-regulatingpilot.Three different sprinkler packages with three different nozzle sizes were identified. Flowvariation due to the different sprinkler – nozzle combinations (emitter variation) is 35.94% andis higher than the recommended 10% from the average discharge. The average applicationrate of the above combination is 1.45m³/hr and is above the design application of 1.4m³/hr.The different sprinkler packages have an effect, also on the wetting diameter due to thedifferent body trajectory angle and nozzle size has an effect flow.Management:Irrigation scheduling is not practised and a proper irrigation scheduling tool will have to beintroduced to the industry, especially for small holder farmers association. Various schedulingtools are widely used in the industry and these include tensiomentry, neutron probes etc.Performance of this irrigation scheme is affected, to some extend, by a lack and/or lateapplication for fertilisers, herbicides, high interest rates, high electricity cost, and the everincreasing transportation cost.Apart from these problems, operation, management and maintenance of this scheme iscomplicated by the lack of a proper maintenance plan for pumps, lack of an operation andmaintenance manual, insufficient training on different components of system, old and wornoutequipment, and frequent breakages of pumps, laterals and draglines.Mabhudlweni Farmers Limited Report - 2009 Page - 45 -

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.Mabhudlweni Farmers Limited Report - 2009 Page - 46 -

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.Mabhudlweni Farmers Limited Report - 2009 Page - 47 -

11 P R O D U C T I N F O R M A T I O NMabhudlweni Farmers Limited Report - 2009 Page - 48 -

Sprinkler equipmentMabhudlweni Farmers Limited Report - 2009 Page - 49 -

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Soils classification according to SSAMabhudlweni Farmers Limited Report - 2009 Page - 51 -

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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 layoutMabhudlweni Farmers Limited Report - 2009 Page - 53 -

SEB usage for River pump station Phase 1 & 2Annual WaterWater requirement use 14000m³/Year 24.75 Total water use in year 346500 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 monthmain28066.526680.534234.231496.8530457.35 17186.4 9909.918814.95 31808.7 39847.541406.75 36590.4Water use per hour 39 62.2 79.8 73.4 71.0 40.1 23.1 43.9 74.1 92.9 96.5 85.3Main pumps Needed 0.4 0.6 0.8 0.7 0.7 0.4 0.2 0.4 0.7 0.9 1.0 0.9River Pumps practical 1 1 1 1 1 1 1 1 1 1 1 2kW use for Main Pump 31.39 31.39 31.39 31.39 31.39 31.39 31.39 31.39 31.39 31.39 31.39 31.39Total kVa Demand 62.78 62.78 62.78 62.78 62.78 62.78 62.78 62.78 62.78 62.78 62.78 125.56Total kw use for themonth8810.07 1405618035.416593.33 16045.79054.2285220.7859912.18916757.6220992.66621814.1219276.74Total Max. Demand costs4358.194358.194358.194358.1884358.1884358.1884358.1884358.1884358.1884358.18764358.1888716.375Total kW cost1938.223092.313967.80 3650.53 3530.05 1991.93 1148.57 2180.68 3686.68 4618.39 4799.11 4240.88Total Energy Cost /month 6296.4 7450.58325.988008.7217888.2416350.118 5506.766538.8698044.8658976.57429157.29412957.2695501.59Mabhudlweni Farmers Limited Report - 2009 Page - 54 -

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 0.160Mabhudlweni Farmers Limited Report - 2009 Page - 55 -

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