Service Contract No 2007 / 147-446 - 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 p h o b e n i F a r m e r s A s s o c i a t i o nSubmitted 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.deMaphobeni Farmers Association 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.Maphobeni Farmers Association Report - 2009Page iii

TABLE OF CONTENTSMaphobeni Farmers Association ....................................................................................................................... iTABLE OF CONTENTS ................................................................................................................................. ivLIST OF TABLES ............................................................................................................................................ viLIST OF FIGURES ......................................................................................................................................... viiLIST OF APPENDICES ................................................................................................................................ viiiABBREVIATIONS ........................................................................................................................................... ix1 INTRODUCTION ............................................................................................... - 1 -2 BACKGROUND ON IRRIGATION DEVELOPMENT ....................................... - 2 -2.1 The project .............................................................................................................................................- 2 -3 TECHNICAL AUDIT REPORT .......................................................................... - 4 -3.1 REVIEW OF THE IRRIGATION DESIGN CRITERIA AND SPECIFICATIONS .....................- 4 -3.1.1 Irrigation Design and Specifications ...................................................................................................- 4 -3.1.1.1 General .......................................................................................................................................- 4 -3.1.1.2 Planning .....................................................................................................................................- 4 -3.1.2 Review of Contactor’s Irrigation Design Criteria and Specifications .................................................- 5 -3.1.2.1 Planning .....................................................................................................................................- 5 -4 FIELD EVALUATION OF IRRIGATION SYSTEM .......................................... - 14 -4.1 Pumps and Pump Stations ..................................................................................................................- 14 -4.1.1 Pump Suction Side ............................................................................................................................- 14 -4.1.1.1 Suction Pipe Flow Rate ............................................................................................................- 14 -4.1.1.2 Requirements for Fittings .........................................................................................................- 15 -4.1.1.3 Suction Pipe Inlets ...................................................................................................................- 18 -4.1.1.4 Suction side losses ...................................................................................................................- 20 -4.1.1.5 Suction height ..........................................................................................................................- 21 -4.1.1.6 Pump evaluation .......................................................................................................................- 22 -4.1.1.6.1 Power required on the pump shaft ......................................................................................- 23 -4.1.1.6.2 Pump Operation ..................................................................................................................- 24 -4.1.1.6.3 Output Power ......................................................................................................................- 24 -4.1.1.6.4 General ................................................................................................................................- 25 -4.2 Power Supply and Consumption .......................................................................................................- 28 -4.3 Supply System .....................................................................................................................................- 30 -4.3.1 Mainline size .....................................................................................................................................- 31 -4.3.2 Mainline class ...................................................................................................................................- 31 -4.4 System Capacity Evaluation ...............................................................................................................- 31 -5 FIELD EVALUATION OF SPRINKLER IRRIGATION SYSTEM .................... - 33 -5.1 Pressure readings ................................................................................................................................- 34 -5.1.1 Pressure at hydrant ............................................................................................................................- 34 -5.1.2 Sprinkler pressure .............................................................................................................................- 35 -Maphobeni Farmers Association Report - 2009Page iv

5.2 Delivery tests ........................................................................................................................................- 43 -5.2.1 Sprinkler discharge ...........................................................................................................................- 43 -6 ASSESSMENT OF OPERATION, MANAGEMENT AND MAINTENANCE OFTHE IRRIGATION SYSTEM .................................................................................. - 46 -6.1 Operation .............................................................................................................................................- 46 -6.2 Management Practices ........................................................................................................................- 49 -6.3 Maintenance Survey ...........................................................................................................................- 51 -7 CONSTRAINTS TO EFFICIENT SYSTEM PERFORMANCE ........................- 53 -8 RECOMMENDATIONS ...................................................................................- 57 -9 CONCLUSION ................................................................................................- 60 -10 LITERATURE REFERENCES .....................................................................- 61 -11 PRODUCT INFORMATION .........................................................................- 63 -12 APPENDICES .............................................................................................- 76 -Maphobeni Farmers Association Report - 2009Page v

LIST OF TABLESTABLE 1. PUMP AND MOTOR SPECIFICATIONS AND MEASUREMENTS CONDUCTED ON BOOSTER PUMPS ... - 23 -TABLE 2. ............................................................................................................ ERROR! BOOKMARK NOT DEFINED.TABLE 3: NORMS FOR PRESSURE VARIATIONS OVER DIFFERENT FILTER BANKS (KOEGELENBERG, 2002) .... ERROR!BOOKMARK NOT DEFINED.TABLE 4 SUMMARY OF DRIP BLOCKS ............................................................. ERROR! BOOKMARK NOT DEFINED.TABLE 5. CRITERIA USED TO CLASSIFY MAINTENANCE PRACTICES ................ ERROR! BOOKMARK NOT DEFINED.TABLE 6. MAINTENANCE PRACTICES IMPLEMENTED BY MAPHOBENI FA ....... ERROR! BOOKMARK NOT DEFINED.TABLE 7. ............................................................................................................ ERROR! BOOKMARK NOT DEFINED.Maphobeni Farmers Association Report - 2009Page vi

LIST OF APPENDICESAppendix 1: SEB usage for pump stationsAppendix 2: Capital recovery factors (CRF)Appendix 3: Soil map and block layoutMaphobeni Farmers Association Report - 2009Page viii

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 UniformityMaphobeni Farmers Association Report - 2009Page ix

1 I N T R O D U C T I O NAssociation general information1. Farm name: Swazi Nation Land2. Name of Association: Maphobeni Farmers Association3. Location:Area:Siphofaneni - MaphobeniLatitude 80 000.00Longitude - 2 961 000.00Altitude145 mMaximum Temperature39 0 CMinimum Temperature8 0 C4. Postal address: 277 Matata5. Contact Details:Chairman – Mr. E. Ngcamphalala 654 5854Farm Supervisor – Mr. B. Msibi 654 58546. Area of farm (ha) 1517. Crops irrigated: Sugar cane8. Designers name and details:Phase 1:A.J. NymanPhase 2:SII9. Date of evaluation: 9 July 200910. Evaluators: Tiekie de Beer and Bongani BhembeMaphobeni Farmers Association 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 TMaphobeni Farmers Association is located in the lowveld of Swaziland in Siphofaneni inan area called Maphobeni. This Association was founded by 40 members in 1994. Todate membership has increased to over 68 members and the area under sugarcaneenlarged from 56 ha to 151 ha.2 . 1 T h e p r o j e c t‣ This 151 ha was designed, installed and commissioned in two phases by two differentcontractors. The first phase was 56 hectares commissioned in 1994 by AJ Nyman.The second phase was 95 hectares implemented in 2002 by a Swazi based companyS.I.I under the leadership of Mr. Tiekie De Beer.‣ Phase one was constructed in 1994 and comprised of a pump station next to theUsuthu river housing one low speed double stage ETA 125-50/2 pump. This pump isdriven by a four pole 75kW motor.Figure 1. Phase one pump house along the Usuthu River‣ According to Maphobeni management this phase was designed for maize productionand latter sugarcane was planted. Laterals are 216 meters apart, 100m draglines inuse and there are no hydraulic valves.‣ In 2002 the second phase of 95 ha dragline irrigation was designed and implementedby S.I.I. a second pump station, constructed along the river, supplies a booster pumpstation via a balancing dam. Both the river and booster pump stations have twoMaphobeni Farmers Association Report - 2009 Page - 2 -

pumps. 2 x Howden 100-400 in the river pump station and 2 x Howden 100-250 in thebooster pump station.Figure 2. Maphobeni balancing dam‣ An intake sump was constructed with phase two river pump station. A provision wasmade for phase one.‣ Phase two laterals and sub-mains were designed so as to handle flow from allhydromatics along the lateral. Generally they start of from the sub-main as 75mmreducing to 63mm then 50mm at the end.‣ The size of phase one lateral is not known for sure.‣ Maphobeni irrigation scheme was developed on three types of soils, the Lesibovu,Rondspring and Somerling soil series. The L and R sets are deep, red, wellstructured, free draining soils with high water holding capacity and highly fertile. The Ssets are type three soils (land classification) with shallow but well structured soils,draining freely, and low water holding capacity.‣ Three sugarcane varieties are under cultivation, N23, N19 and NCo376Maphobeni Farmers Association 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 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 I r r i g a t i o n D e s i g n a n d S p e c i f i c a t i o n s3.1.1.1 GeneralDesign information from the designers of both phases and from the client representativeduring construction, Ubombo Sugar could not be obtained. The design was therefore checkedagainst Swaziland sugar standards and SABI norms.The following is the design criteria used in the sugar industry against which this project wasevaluated on.3.1.1.2 PlanningThe main criteria for the irrigation systems are given below:CropSugarcaneDesign irrigated area 151 HaGross Application 52 mmNet Application39 mmIrrigation Cycle6 DaysSprinkler discharge 0.39l/sSprinkler Spacing 18 m x 18 mApplication Efficiency 75%Stand Time12 hours (depending on soil)Gross Precipitation 4.33 mm/hourAnnual Irrigation hours 3 300 hoursMaphobeni Farmers Association Report - 2009 Page - 4 -

3.1.2 R e v i e w o f C o n t a c t o r ’s 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 s3.1.2.1 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 SugarAssociation). Design documentation could not be obtained but site investigations revealedthat the irrigation system developed only of good soils (mostly type I soils, only block I is ontype III soils). Based on this, soils were taken into account in the design.Attached in appendices is a soil map of Maphobeni Farmers Association indicating major soiltypes the project was developed on. Information on whether soils were taken into accountduring design could not be found.The purpose of this study was, therefore, to determine the quantity of water required by thecrops per cycle during peak demand periods and how often it was to be applied takingpractical operating practice into account.Taking soils into account the following planning schedule was developed;Peak Design-Norm For Sprinkler Irrigation At Maphobeni Farmers Ass.1 GENERAL INFORMATION1,1 Owner Maphobeni Farmers Association1,2 Farm Name - Number - Co-ordinates Swazi nation land1,3 Telephone number1,4 Area developed 151 Ha1,5 Water Allocation 100 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 24Maphobeni Farmers Association Report - 2009 Page - 5 -

4 CROP BLOCK NO Lesibovu/Short./Oakleaf Somerling/Glenrosa4,1 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 Lesibovu/Short./Oakleaf Somerling/Glenrosa5,1 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 River7 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 24 248,12Gross application rate per practicalcycle mm 51.48 25.748,13 Gross application per month mm 220.62 257.40Maphobeni Farmers Association Report - 2009 Page - 6 -

9 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 111PRACTICAL STAND TIME / START TIMEfor 6 Day Cycle length11,1 Position 111,2 Position 211,3 Position 311,4 Position 411,5 Position 511,6 Position 611,7 Position 711,8 Position 811,9 Position 911,10 Position 1011,11 Position 1111,12 Position 1211,13 Position 1 start at beginning againStart EndDay 106,00 Day 1 18,00Day 118,00 Day 2 06,00Day 206,00 Day 2 18,00Day 218,00 Day 3 06,00Day 3Day 306,0018,00Day 3Day 418,0006,00Day 406,00 Day 4 18,00Day418,00 Day 5 06,00Day 506,00 Day 5 18,00Day 518,00 Day 6 06,00Day 6Day0606,0018,00Day 6Day 718,0006,00Day 806,0012 FILTER12,1 Type State12,2 Total total12,3 Filtration size micron12,4 Pressure loss over filter (clean) m12,5 Pressure lose over filter (dirty) m13 DESIGNER13,1 Name Tiekie de Beer13,2 Company Tiekie de Beer Consulting13,3 SABI Membership Designer FellowMaphobeni Farmers Association Report - 2009 Page - 7 -

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.Maphobeni Farmers Association 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 P u m p s a n d P u m p S t a t i o n s4.1.1 P u m p S u c t i o n S i d eThe majority of problems occurring with pumps are usually the result of poor suction sidedesign and installation. The installation and designed of the suction side must ensure thatturbulence occurring and collection of air in high places in the suction pipe, is prevented. Inview of the above, the different suction side components are evaluated.4.1.1.1 Suction Pipe Flow RateThe suction pipe flow velocity of river and booster pumps is 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).This 151 hectares dragline irrigation system development has three pump stations, two riverpumps and one booster pump station. Pump station one (PS1) supplies 56 ha phase onedevelopment, and phase two of 95ha has a river pump station and a booster pump station.PUMP STATION 1: Phase One Pump StationThis pump station has one KSB ETA 125-50/2 pump driven by a two pole 75kW motor andirrigates a total area of 56ha. The design duty point of this pump is not known. But forpurposes of the evaluation the pump discharge was determined getting a multiple of the totalirrigated area, industry norms of 2.57 sprinklers per hectare (12 positions per sprinkler),1.4m3/hr sprinkler discharge and 10% safety factor for pump discharge. the pump musttherefore generate at least 221.6 m³/hr.Maphobeni Farmers Association Report - 2009 Page - 14 -

Based on equation 1 above the flow velocity, through the 200mm suction manifold is 2.1m/sand 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. Theexcessively high suction flow velocity in the suction pipe causes turbulence in the pipe, thuscausing irregular feeding of the pump (and eventually causes cavitation). As a result impellorwearing is excessive and thus explains the poor performance by this pump. Maintenancecosts are high as a result.PUMP STATION 2 – Phase Two River Pump StationThis pump station has two Howden 100-400 pumps each driven by low speed 30kW motors.These pumps supply water to a small earth dam irrigating responsible for supplying water to95 hectares. The design duty point of these pumps could not be ascertained but in order formeet sugarcane irrigation requirements these pump must generate at least 376m3/hr totalflow. Each pump therefore has a duty of at least 188m3/hr flow and using equation oneabove, flow velocity through the 250mm suction pipe is 1.11 m/s. this suction pipe is correctlysized and its flow velocity is within recommendations.PUMP STATION 3 – Phase Two Booster Pump StationThese pumps design duty point is also not known but was calculated to be the same as thatof PS 2. The two identical Howden 100-250 high speed pumps in this pump station musttherefore generate at least 188m3/hr each and the flow velocity at this flow through the250mm suction manifold is 1.11 m/s and is within recommended limit.4.1.1.2 Requirements for Fittings90º BendsThe radius (mm) of a 90º bend must be, at least, as shown in Figure 4 belowMaphobeni Farmers Association Report - 2009 Page - 15 -

dFigure 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).All 90° bends measured in the three pump stations had a shorter radius than required.200mm 90° bends in PS 1 are 200mm in radius and PS 2 and 3 250mm 90° bends have aradius of 350mm. According to figure 4 and equation 2 above the required minimum radius is500mm and 600mm for the two sizes respectively. However, there is more than five time thesuction and delivery pipe size diameter pipe further on from these bends; the effects of theincorrect sizes are insignificant.Figure 5. 90° suction bendsMaphobeni Farmers Association Report - 2009 Page - 16 -

ReducersThe 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 lengths ofboth eccentric and concentric reducers are evaluated against equation 3 below, adopted fromthe ARC (Figure 6).Figure 6. Concentric and eccentric reducers ( d ) ………………………... (3)52d1Where: = length of the reducer (mm)d1 = smaller inner diameter (mm)d2 = larger inner diameter (mm)Concentric and eccentric reducers were installed as per recommendations on all pumps.Eccentric reducers were installed with the straight side towards the top, to prevent aircollecting in the pipe and causing cavitation. The length of the 150-200, 125-250 and 125-250eccentric reducers attached to PS 1 and PS 2 and PS 3 respectively is 150mm, 120mm and630mm in length respectively. According to equation 3 above these should be 250mm,625mm and 625mm respectively. Only PS 3 has correctly dimensioned eccentric reducers.The incorrectly dimensioned concentric reducers affect pump performance substantiallybecause they are directly attached to the pumps and the sudden restriction in size increasesturbulence occurrences and cause irregular feeding of the pump hence cavitation. With suchan installation wearing and maintenance cost of the pump will increase.Maphobeni Farmers Association Report - 2009 Page - 17 -

Figure 7. Eccentric reducer PS 1 and PS 3 suction manifoldA 125-150 concentric reducer was installed in PS1 pump and 130mm in length. PS 2 and PS3 pumps are attached to 100-200 concentric reducers 150mm in length. The unacceptabledimensions of the concentric reducer had negligible effects on the performance of the pumpand the entire system.Figure 8. Concentric reducer in delivery manifold4.1.1.3 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 9) and at least 1,5d away from the side of the pump sump.Maphobeni Farmers Association Report - 2009 Page - 18 -

d1.5d0.5dd3d 3d 1.5dFigure 9. Spacing and placing of suction pipe inletsA proper intake structure was constructed for phase two river pump station and some of theabove requirements are not satisfied (figure 10). For example the suction pipes are installedtoo close to the sump. Over the years the level of the Usuthu River has dropped and adiversion channel is used to redirect water back into the sump.Figure 10. Intake sump and suction pipes for PS 2A proper intake structure was not constructed in PS 1 instead the suction inlets (foot valves)are suspended at the end of another diversion channel from the Usuthu River (figures 9). Thefoot valves are not protected in any way and are intermittently in direct contact with thebottom of the channel and debris carried with the river water.The evaluation revealed that this FA loses at least a week every month as a result of a dropin the river level and sand accumulation along the banks. Occasionally farm managementconstruct a diversion channel using sand bags rerouting water back into the suction inlets.Maphobeni Farmers Association Report - 2009 Page - 19 -

Phase two booster pumps are supplied from the adjacent small earth dam and the outlet ofthe dam does not have strainers. The outlet pipe is approximately 1.5m form the bottom ofthe dam. The installation height of the outlet pipe reduces the effective storage capacity of thedam by almost a third.The minimum water depth above suction pipe inlet depends on the suction pipe velocity andwas evaluated using the graph shown in figure 14 below. Site investigation revealed that PS1 and PS 2 foot valves are 200mm and 700mm below the water level respectively. With asuction velocity of 2.1 and 1.1m/s the depth should be at least 1.1m and 0.75m respectivelyas indicated in figure 11 below.Figure 11. Minimum water depth above suction pipe inletPhase two booster pumps are installed at a lower level than the minimum water level in thereservoirs, which ensured that there is always water in the pump casing and suction pipe.This is the most preferred pump design criteria and installation was in accordance to thestandards.4.1.1.4 Suction side lossesDuring the evaluation of the pump station, attention is also given to the length of the suctionpipe and fittings that were used. Friction losses for pipes are calculated as for any other pipe(using Hazen-Williams equation) and secondary losses for fittings are calculated with the aidof the following formula:Maphobeni Farmers Association Report - 2009 Page - 20 -

hf6375kQ4d2………………………………….. (4)A summation of friction loss across the river pumps foot valves, the suction pipe, and theeccentric reducer gave a total hf of 0.72m, 0.2m and 0.5m for PS1, PS 2 and PS 3respectively. Friction in the suction pipe has a direct effect on maximum suction height andconsequently the available net positive suction head (NPSH) and is discussed below.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).4.1.1.5 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 is 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)Maphobeni Farmers Association Report - 2009 Page - 21 -

Figure 12. Atmospheric pressure vs. height above sea levelThe suction height of PS 1 and PS 2 was measured to be approximately 4 and 3 metersbelow the impellor eye respectively. The NPSH required (NPSHr) of the pumps in this pumpstations is 1.5m and 4.5m respectively (see attached pump curves). PS 3 pumps have anNPSHr of 3 meters. From the above formula the maximum allowable suction height is 7.38m,4.9m and 6.1m for the pumps in the three pump stations respectively. These calculationsconfirm that all pumps were installed with correct suction height.Further analysis compared NPSH available to NPSH required and all pumps in this irrigationscheme conforms to the recommendation of NPSHr

Table 1. Pump and motor specifications and measurements conducted on booster pumpsPUMP SPECIFICATIONS FROM INFORMATION PLATE AND MEASUREMENTSMake / model ETA 125-50/2 Howden 100-400 Howden 100-250Pump identification Phase 1 Phase 2 river Phase 2 boosterNumber of units 1 2 2Pump Duty (estimated) 222m³/hr @ 80m 188m³/hr @ 35m 188m³/hr @ 90mImpeller diameter mm 405/330 385 245Pressure under normal operation (H) m - 30 60MOTOR SPECIFICATIONS FROM INFORMATION PLATE AND MEASUREMENTSModel and type Alstom Dutchi DutchiPower (P motor) kW 75 30 75Power factor (cos ø) 0.87 0.88 0.91Speed rpm 1475 1450 29654.1.1.6.1 Power required on the pump shaftThe power required on the pump shaft is calculated once the total pump head and delivery ismeasured. The pump efficiency is obtained from the pump curve. The following formula wasused to establish whether motors are 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 61.26kW for the phase 1 pumps, 25.08kW for phase two riverpumps and 67.8kW for phase two booster pumps. According the ARC the power output of themotor must be 10-15% greater than the power required on the pump shaft and correspondsto 67.4kW, 27.6kW and 74.6kW respectively. Under this consideration, the 75kW, 30kW andMaphobeni Farmers Association Report - 2009 Page - 23 -

75kW motors that drive these respective pumps are correctly specification. Phase twobooster pumps are driven by high speed motors, these are not recommended.4.1.1.6.2 Pump OperationPump curves of all the pumps are used to evaluate whether these pumps function asindicated by the pump curve. Measurements of the operational pressure and discharge fromthese pumps were used for this exercise but because no flow meter was installed in thisproject this could not be carried out. Pressure measurements however revealed that allpumps are operating below their recommended duties. For example, at closed valve pressurethe Howden 100-400 pump generated 400kPa. The operating curves indicate that, at no flowthese pumps should be able to deliver at least 500kPa (at 385mm impellor diameter).4.1.1.6.3 Output PowerThe required powerPrequiredof the pump, calculated above, is then compared with the outputpower (Pu) of the electric motor obtained from measurements of voltage and current. Theoutput power of the motor is calculated using equation 7 below3IV cosP u……………………………………….. (7)1000Where: Pu = output power of the motor (input power of the pump) (kW)I = average measured current (A)V = average measured voltage (V)η = motor efficiency (fraction)cos ø = power factor (factor).The output power of motors that were in operation during the evaluation is indicated in table 2below. One of phase one pump was not running because it had a faulty foot valve. The builtinnon-return valve could not stop backflow of water and the pump could not be primed.Maphobeni Farmers Association Report - 2009 Page - 24 -

Table 2. Irrigation pumps evaluationETA 125-50/2 Howden 100-400 Howden 100-250Measure Current A 55 20 90Measured Voltage V 400 380 380P motor (information plate) kW 75 30 75P required kW 61.26 25.08 67.8Pu (motor output power) kW 31.5 11 51.7Classification Acceptable Acceptable AcceptableAccording to the ARC the configuration of the different power units must conform to theexpression Pu = P < Pmotor. The observed deviation from this expression is because thesepumps were operating below optimum. Some blocks were not irrigated because the cane ison dry-off.4.1.1.6.4 GeneralPhase one pump station:‣ The access ladder into this pump house is very steep, made of timber and without handrails. This is not safe.Figure 13. Access ladder into pump house‣ The floor does not have the correct slope to drain all its water out of the pump house.Also, there is no drainage sump and pump.‣ This pump has excessive cooling leaksMaphobeni Farmers Association Report - 2009 Page - 25 -

‣ Bermad control valves connected in all pumps are malfunctioning and there are nomechanical pump control valves.‣ The pump house is used as a storeroom and this reduces ventilation, working space andincreases risks.‣ The pump house is not well ventilated.‣ There is no carriage (gantry and winch) for the pump and/or motor for maintenancepurposes‣ Some pressure gauges, and voltmeter are not functioning and electric cables aredisoriented inside the pump station.‣ This pump is equipped with only mechanical valves, no hydraulic pump control valves.‣ The pump house needs finishingPhase two river pump station‣ Floor of pump house not properly draining and full of oil.‣ Pump and motor safety mechanisms must be improved.‣ All pumps have excessive cooling leaks‣ Electric cables are not protected and are all over pump station 1‣ Pumping units in both pump stations have no safety mechanisms‣ Pump and floor drainage need improvement‣ All pumps are equipped with only mechanical valves, no hydraulic pump control valves.‣ MCCs are incompletely equipped, all meters are not working and the door can no longerlock.‣ Access ladder not properly anchoredFigure 14. Inside phase two river pump stationMaphobeni Farmers Association Report - 2009 Page - 26 -

Phase two river pump station‣ Pump and floor drainage need improvement‣ Both pumps have excessive cooling leaks‣ Pump and motor safety mechanisms must be improved.‣ Pump house is well ventilated, enough working space and cleanFigure 15. Inside phase two booster pump housePump AlignmentThe alignment of the pump and the motor is also evaluated. This is done by placing the edgeof a straight steel ruler over the coupling flanges at four points, 90º apart. The straight edgerested equally on all points on the flanges to ensure parallel alignment. The distancebetween the coupling levels at 90º intervals is also measured. A Vernier calliper is used. Themeasurements are the same on all the points and on all the pumps and that meant the unitwas squarely aligned.Maphobeni Farmers Association Report - 2009 Page - 27 -

4 . 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 are:‣ 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 are confined to energy costs and maintenance(excluded labour. Admin etc).Interest rate: 10%Useful life (this analysis)Infield irrigation (Tape etc):10 yearsPVC/Poly pipe:Filters:Pumping equipment and electricsMaintenanceInfield irrigation: 3%Distribution - pipelines: 2%Pumping plant: 1%20 years15 years15 yearsMaphobeni Farmers Association Report - 2009 Page - 28 -

Filters: 3%Capital Recovery Rate (CRF)factors:Volume water applied per hectare:SEB tariff – Consumption:Maximum demand:Efficiency of pumping plant(See attached table)9000mI\3/ha/annum0.22 E/kWh69.42 E/kVaCalculate at design duty pointEAC COMPUTATION MATRIXThese costs have been calculated only for Phase One 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) 226,207.26Total EAC (E) -Energy cost as a % of total EAC -Maphobeni Farmers Association Report - 2009 Page - 29 -

EAC COMPUTATION MATRIXThese costs have been calculated only for Phase Two of theProjectITEM COST ITEM Main Bid1 Infield irrigationCapital cost (E) 1,080,800.00Useful life (years) 10Annual maintenance (%) 3EAC of infield irrigation (E) 208,594.402 Distribution systemCapital cost (E) 1,440,040.00Useful life (years) 20Annual maintenance (%) 2EAC of Distribution system (E) 197,285.483 Pumping plantCapital cost (E) 173,040.00Useful life (years) 15Annual maintenance (%) 1EAC of Pumping plant (E) 24,398.644 FiltersCapital cost (E) -Useful life (years) 15Annual maintenance (%) 3EAC of Filters (E) -5 Annual Energy Cost (E) 404,175.63Total EAC (E) 430,278.52Energy cost as a % of total EAC 93.93For sprinkler irrigation a 40% EAC value is accepted. A higher and a lower figure indicatesover design and under design respectively4 . 3 S u p p l y S y s t e mThe evaluation of the supply system is discussed under the following headings;Maphobeni Farmers Association Report - 2009 Page - 30 -

4.3.1 M a i n l i n e s i z eThe South African Irrigation Institute (SABI) norm suggests that for raising main lines with adiameter of 200mm or smaller a maximum of 1.5% is allowed (ARC, 2003). Mainlines withpipe sizes greater than 200mm are evaluated by determining the most economical pipediameter; capital and annual cost for different pipe diameters are compared and the followingequation is used;dkQ0.37i …..……………………….……… (8)Where: di = inside diameter of pipe, mmK= constantQ= flow rate (m3/h)No information was available on mainline pipe sizes, lengths and class and because thereare no pressure measuring points on hydrants, friction loss through the mainline could not becalculated. An undisputed conclusion, therefore, on whether the supply system was correctlydesigned or not cannot be drawn until details on pipe size, pipe classes, and distancesoccupied by the different sizes are obtained.4.3.2 M a i n l i n e c l a s sJust like above, this evaluation could not identify as to whether the mainline classes wereover-specified or not. Pipe bursts are one major indicator of under-specification in pipeclasses and recurrent pipe breakages were experienced only in phase one mainlines, submainsand laterals.4 . 4 S y s t e m C a p a c i t y E v a l u a t i o nPhase One:‣ Phase one of 56 hectares is supplied by one pump and requires at least 222m3/hr.‣ Pressure requirements are estimated at approximately 80m‣ This pump duty point is within the operating range of the installed ETA 125-50/2 pump. Infact, a smaller and cheaper ETA 100-250 single stage pump could have been used.‣ Pressure measurements results reflected that this pump is operating below their designduty point.Maphobeni Farmers Association Report - 2009 Page - 31 -

Phase Two:‣ This phase is supplied by a river pump and a booster pump station, each of these pumphouses have two pumping units‣ This phase is 95 hectares and requires at least 376m3/hr flow to meet irrigationrequirements.‣ Water from the Usuthu River is pumped by two identical Howden 100-400 pumps eachdriven by a 30kW two pole motor into a small balancing dam.‣ In order to meet irrigation requirements each of these pumps must generate at least188m3/hr system flow.‣ Pressure requirements from the pump station to the balancing dam are estimated at 35m‣ This duty point is within the operating range of the installed river pumps.‣ Pressure requirements from the balancing dam to the critical sprinkler are estimated at90m. The impellor diameter of these pumps is 246mm and in order for these pumps togenerate the required pressure a 255mm impellor diameter must be installed in thesepumps.‣ Both booster pumps can deliver the required 188m3/hr system flow.Maphobeni Farmers Association Report - 2009 Page - 32 -

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 MPhase onePhase twoBlock Area (Ha) 56 95Type of sprinkler system Dragline Irrigation System Dragline Irrigation SystemName of Designer A.J. Nyman S.I.I.Name of contractor A.J. Nyman S.I.I.Design Measured Design MeasuredSprinkler spacing (m x m) 18 18 18 17.5 - 19Lateral spacing (m) 54 35 – 62 54 200Stand pipe height (m) 3 3 3 3Pressure regulator Yes No Yes NoDragline diameter (mm) 20 20 20 20Dragline length (m) 45 54 2 100Maphobeni Farmers Association Report - 2009 Page - 33 -

5 . 1 P r e s s u r e r e a d i n g sThe following pressure readings were taken:5.1.1 P r e s s u r e a t h y d r a n tPressure controlThe lateral of the irrigation system that was installed by S.I.I. (phase two) are equipped withmechanically chocked hydraulic valves. Pressure-regulating pilot are not installed. Phase onelaterals are equipped with mechanical valves; there are no hydraulic valves in this phase.Pressure-regulating pilots (on the valve head) reduce a higher inlet pressure to a lowerconstant outlet pressure, regardless of fluctuating flow rates and or varying inlet pressure.The pilot would sense down-stream pressure and modulates open or close, causing the mainvalve to throttle, thus maintaining constant delivery pressure.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 16. Lateral hydrant valveMaphobeni Farmers Association Report - 2009 Page - 34 -

5.1.2 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 2. 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 2784,374,765,165,565,956,3511 / 64 " 262 3063 / 16 " 286 33313 / 64 " 310 36115 / 64 " 333 38915 / 64 " 357 4271 / 4 " 381 445Pressure at sprinklers was measured with a pressure gauge, fitted with a pitot tube (Figure17). The point of the pitot tube was held about 2 mm in front of the nozzle opening in the pathof the jet of water to measure the “vena contracta”. Therefore, the velocity pressure, whichindicates the pressure head and is equivalent to the total pressure, was measured.Maphobeni Farmers Association Report - 2009 Page - 35 -

Figure 17. Pressure measurement with a pitot tube end pressure gaugeThe standpipes were three metres high and the pressure of the sprinklers was measured at aheight of one metre above the ground, then 2 m (or 20 kPa) was subtracted from thepressure registered on the pressure gauge, in order to determine the sprinkler pressure atnormal operating height.The choice of the sprinklers at which measurements were to be taken, was influenced by thedifferent pressure zones in a specific irrigation block. In view of the undulating terrain (manyheight differences) in this project the total system was in operation as for normal irrigationbefore the evaluation. According to the ARC (2006) the number of measuring points must berepresentative of the block and the choice depended on the topography of the block, as wellas the distance from the pump station. As per these recommendations completemeasurements were taken at distances 0, L/4, L/2, 3L/4 and L on the lateral and at the samedistance on the sprinkler lines (Figure 18).Maphobeni Farmers Association Report - 2009 Page - 36 -

0 L/4 L/2 3L/4 LL3L/4LL/2Test blockL/4Test emitter0HydrantFigure 18. Positions of complete sprinkler pressure measures in an irrigation blockPressure variation was calculated using equation 9 below and a summary of the results isoutlined in table 3.Pmax PP Pavemin………………………………………….. (9)Pressure measurement results for the different sections are indicated in the following table.Maphobeni Farmers Association Report - 2009 Page - 37 -

Table 3. Pressure and nozzle size measurements resultsMeasuring point Type of sprinkler/nozzle Measured nozzlediameterMeasurednozzle pressurePhase one RC 140 11/64" nozzle 4.4 440Phase one Rain bird BH30 11/64" nozzle 4.4 220Phase one Rain bird 14070 11/64" nozzle 5 220Phase one Rain bird 14070 11/64" nozzle 4.4 420Phase one Rain bird 14070 11/64" nozzle 4.4 450Phase two VYRSA 35 11/64" nozzle 4.4 340Phase two VYRSA 70 11/64" nozzle 4.5 330Phase two – block I RC 130 11/64" nozzle 4 250Phase two – block I VYRSA 70 11/64" nozzle 4.5 240Phase two – block I VYRSA 70 11/64" nozzle 4.5 230Phase two RC 130 11/64" nozzle 4 350Phase two – block I VYRSA 70 11/64" nozzle 4.5 210Phase two VYRSA 70 11/64" nozzle 5 290Phase two VYRSA 70 11/64" nozzle 5 360Phase two VYRSA 70 11/64" nozzle 5 330Phase two VYRSA 70 11/64" nozzle 5 360Average Pressure (kPa) 350.5 299.09Minimum Pressure (kPa) 220 210Maximum Pressure (kPa) 450 360Pressure Variation (kPa) 65.71 50.15According to the SABI norms, pressures in the infields may not vary more than 20% from theaverage pressure. Pressure measurement results as indicated by the above table reflect anunacceptable pressure variation of 65.71% for phase one and 50.15% for phase two. Theaverage system operating pressure is 350.1kPa and 299.09kPa for the two phasesrespectively. Phase one average sprinkler operating pressure is above the recommendedsprinkler operating pressure of 350kPa. Phase two average sprinkler operating pressure, onthe other hand is lower that the recommended 350kPa.The least amount of pressure was recommended on blocks I. this block is on top of a smallhill at the highest elevation and all hydromatics in the lateral were connected to sprinklers.Each lateral had up to 23 operating sprinkler connected to it.The following is an outline some of the factors affecting the above pressure reading;Maphobeni Farmers Association Report - 2009 Page - 38 -

Phase two booster Pumps running under pressurePressure requirements from the balancing dam (booster pumps) to the critical sprinkler areestimated at 90m. The impellor diameter of these pumps is 246mm and in order for thesepumps to generate the required pressure a 255mm impellor diameter must be installed inthese pumps. The critical sprinkler in this project is on block I and pressure measurementfrom this block reflected that they were not receiving the recommended pressure.When pressure measurements from this block are excluded from the analysis systempressure variation drops to an acceptable 20.7% and the average sprinkler operatingpressure increases to 340kPa. The installed Howden 100-250 at the prescribed impellordiameter can generate a maximum of 82m at 188m3/hr system flow requirements, underoptimum operation. This 82m pump pressure is not enough to run sprinkler at 350kPa,especially on this block (block I).Long dragline in phase oneIt has been mentioned earlier that 100m draglines are used in phases one and these aredifficult to move from position to position. Each sprinkler has to make 5 positions on eitherside of the lateral during operation, whilst the dragline is engorged with water. The sprinklerdraglineassembly is therefore heavy and wear and tear of the different components ishastened. When comparing pressure measurements made on sprinkler heads (table 3) tothose made on hydromatics (during operation) the average pressure increased to 514kPaand pressure variation dropped to 31.1% on the latter (table 4).Table 4. comparison of Pressure measurements results made on sprinkler nozzles and hydromaticsType of sprinkler/nozzleMeasured pressure athydromaticsMeasured nozzlepressureRC 140 11/64" nozzle - 440Rain bird BH30 11/64" nozzle 580 220Rain bird 14070 11/64" nozzle 550 220Rain bird 14070 11/64" nozzle - 420Rain bird 14070 11/64" nozzle 580 450Average Pressure (kPa) 514 350.00Minimum Pressure (kPa) 420 220Maximum Pressure (kPa) 580 450Pressure Variation (kPa) 31.13 65.71Maphobeni Farmers Association Report - 2009 Page - 39 -

The analysis showed by table 4 reflects that there are high pressure losses on the longdraglines. Some dragline pressure losses are as high as 360kPa and this is not acceptable.Phase two laterals are 108m and 50m dragline are used. These are more accommodatingthan the above but could be more efficient if shortened to at least 20m.Hydraulic Valves:Hydraulic valves maintain the design lateral/block pressure ensuring uniform pressurethroughout the system. S.I.I. dragline irrigation system was installed in such a way that alllaterals have individual hydraulic valves. These hydrants are equipped with Gulf hydraulicvalves but without pilots for pressure regulation. A mechanical choke was installed on thevalve head instead. Pressure regulating pilots must be installed and preset to give at least350kPa sprinkler operating pressure on all blocks. Most of the hydraulic valves in this phaseare vandalised, incomplete and not properly looked after (figure 19).Figure 19. Lateral hydraulic valvePhase one does not have any hydraulic valves and lateral and dragline pressure on someblocks increases to beyond pipe class rating. For example, the pressure of the first lateralwas measured to be approximately 65m which is higher that the installed class six pipe.Draglines have a pressure rating of about 40m and with such pressure breakages arerecurrent thus increasing system operational/maintenance costs. All laterals must beequipped with hydraulic valves equipped with a pressure-regulating pilot.Maphobeni Farmers Association Report - 2009 Page - 40 -

The installation of this unit (on the valve head) reduces a higher inlet pressure to a lowerconstant outlet pressure, regardless of fluctuating flow rates and or varying inlet pressure.The pilot would sense down-stream pressure and modulates open or close, causing the mainvalve to throttle, thus maintaining constant delivery pressure.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 desiredpressureSprinkler pressure regulators:The project was implemented on an uneven topography with approximately 20m elevationdifferent between the project and this directly affect sprinkler operating pressure. When flowis downhill pressure is gained and the reverse is true. Sprinkler pressure regulators were notinstalled hence the increased pressure variation. Pressure regulators are a necessity in thisproject and will have to be incorporated into the system. Some blocks are fairly flat and othersteep. When considering the quantity of the pressure regulators this fact must be kept inmind.Nozzle wearing:Measurements of the amount of sprinkler nozzle wear (mm) taken from phase 1 and twoblocks averaged 3.2% and 5.5% respectively. Nozzle wearing was on maximum 12% in bothphases. An increase of 5% in nozzle area means a 10% increase in flow and power demand,which means additional operating costs and over-irrigation. The ARC therefore recommendssprinkler replacement if wear is greater than 5% and in this project this exercise is longoverdue. Nozzle wearing is hastened, amongst others, by the age of the irrigation system (12years), no intake sump, improper operation and maintenance schedules, etc.Sprinkler nozzles were measured after the system was switched off with a specially machinedapparatus (Figure 20).Maphobeni Farmers Association Report - 2009 Page - 41 -

Figure 20. Measuring apparatus for sprinkler nozzle sizeLeaksTimely 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, as shown in table 4 above. Theeffective application rate of the system decreased. Mainly, these leaks are observed insprinklers, sprinkler stand-dragline connections, broken dragline, pipelets, hydromatics,mainline, etc. it is important that all leaks are located quickly and repaired. A leak preventionprogram should include regular replacement of damaged draglines.Figure 21. Phase one dragline leakagesMaphobeni Farmers Association Report - 2009 Page - 42 -

Old AgePhase one of the irrigation systems was installed in 1994, almost 19 years ago, and as yearselapsed, system efficiency reduces due to equipment wearing out. As a matter of urgencysome equipment must be replaced and the rest maintained for optimal performance. Apartfrom nozzles, sprinklers, due to old age, are underperforming. Some draglines have morethan the allowed tolerance of three joints and hydraulic valves are missing/broken pilots.These and other equipment has to be replaced.Possible ways of improving the hydraulic variation include readjustment of pressureregulating device (installing pilots on all Gulf valves) repair and/or removal of pinchedlateral/sub-main lines and the redesign of the hydraulic system.5 . 2 D e l i v e r y t e s t sThe following delivery tests were conducted:5.2.1 S p r i n k l e r d i s c h a r g eAccording to the ARC the difference in discharge in a specific irrigation block may not vary bymore than 10% from the average discharge, hence this evaluation. The discharge of thesprinklers was tested by collecting water into a container of known volume with a hose pipeconnected to the sprinkler nozzle. A minimum container size of 20 litres is recommended andtogether with a stopwatch the time it took to fill the container was recorded. The open end ofthe hose pipe was not held under water in the container, but also not so high that the watersplashed out of the container.Measurements were again taken at distances 0, L/4, L/2, 3L/4 and L on the lateral and thesprinkler line. The same points where pressure measurements were done were used and bytaking the time it took to fill the container, the discharge was calculated with the followingformula and results are shown in table 4.qe=average volume water measured incontaineraverage duration to fill container (sec)(litres)36001000…………… (10)m3/hourWhere q e = sprinkler discharge [m 3 /h]Maphobeni Farmers Association Report - 2009 Page - 43 -

Flow variation was above the recommended maximum of 10% averaging a high of 45.86%and 51.24% in the two phases respectively. The average sprinkler application for phase oneand two was found to be 1.51m3/hr and 1.28m3/hr respectively; instead of 1.4m3/hrstipulated in the Swaziland sugar industry standards (table 5). Excluding Block I dischargemeasurements the average sprinkler application increases to 1.35m3/hr. Due to the highaverage sprinkler operating pressure phase one sprinkler are discharging more than required.Table 5. Discharge variation calculated from field measurementsType of sprinkler/nozzle sizeMeasured nozzle discharge (m3/hr)RC 140 11/64" nozzle 1.62Rain bird BH30 11/64" nozzle 1.29Rain bird 14070 11/64" nozzle 1.23Rain bird 14070 11/64" nozzle 1.50Rain bird 14070 11/64" nozzle 1.93VYRSA 35 11/64" nozzle 1.28VYRSA 70 11/64" nozzle 1.13RC 130 11/64" nozzle 1.08VYRSA 70 11/64" nozzle 1.24VYRSA 70 11/64" nozzle 1.20RC 130 11/64" nozzle 1.39VYRSA 70 11/64" nozzle 1.05VYRSA 70 11/64" nozzle 1.17VYRSA 70 11/64" nozzle 1.70VYRSA 70 11/64" nozzle 1.31VYRSA 70 11/64" nozzle 1.48Minimum Discharge (m 3 /hr) 1.23 1.05Maximum Discharge (m 3 /hr) 1.93 1.70Average Discharge (m 3 /hr) 1.51 1.28Flow variation (%) 45.86 51.24Sprinkler operating pressure and sprinkler discharge are directly proportional. When pressuredecreases, sprinkler nozzle discharge also decreases and vice versa. This therefore, meansall factors contributing to the low system pressure also contribute to the sprinkler nozzledischarge. The sprinklers that recorded a high operating pressure but low application rate hadleaking draglines, tripods, and/or hydromatic-pipelet connection.Maphobeni Farmers Association Report - 2009 Page - 44 -

The effects of different nozzles/emitters and different sprinkler packages observed in thisproject were evaluated using the table below. Different emitters respond differently to thesame amount of pressure and table 6 below indicates the properties of the different sprinklerpackages found on site.Table 6.Technical properties of sprinklers found on site at 35m operating pressureSprinkler Package Nozzle size Discharge (m3/hr) Wetted Radius (m)VYRSA 70 11/64’’ 1.36 15.9Rain bird 14070 11/64’’ 1.39 15.2Rain bird BH30 11/64’’ 1.38 14.8RC 140 11/64’’ 1.36 15.9Four sprinkler packages and one nozzle sizes was identified in both phases as shown in table6 above. Flow variation due to the different sprinkler – nozzle combinations is 2.18% forphase one and 0% for phase two. Emitter variation, therefore does not affect discharge anddistribution uniformities of this system, except for the wetted radiuses. The averageapplication rate of the above combination is 1.36m3/hr and is acceptable according tosugarcane norms. This different combination has an effect also on the wetting diameter dueto their different body trajectory angles.Gross application rate (GAR)The gross application rate (GAR) of the sprinkler was thereafter calculated, by means of thefollowing formula;GAR qe1000A ....…………………………………. (11) 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 11above. The average GAR for Maphobeni phase one irrigation is 4.2mm/hr and 3.9mm/hr forphase two. The recommended GAR is 4.2mm/hr and this means that Maphobeni FA isslightly under-irrigating phase two. However, when flow measurements readings from Block Iare excluded the GAR of phase two increases to 4.2mm/hr.Maphobeni Farmers Association Report - 2009 Page - 45 -

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 nOperation 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 is notavailable and for efficient performance of these components, it must be compiled. Theconsequence of not having this document is seen during this evaluation in that incorrectsequences are followed in opening and closing the pump. Also, this document helps in theformulation 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.Figure 22. Tonnes Cane per HectaresYield data for the first three seasons could not be obtained but for the above graphproductivity has been on the increase since 2004.Maphobeni Farmers Association Report - 2009 Page - 46 -

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:‣ 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 7 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.Figure 26 below indicates the actual amounts spent on electricity annually since inception.The amounts increase in 2007 because phase two was commissioned and three boosterpumps were in operation. Energy usage of the floppy sprinkler increased from commissioningwhich, in most cases, is attributed to reducing system efficiency.Maphobeni Farmers Association Report - 2009 Page - 47 -

Figure 23. Annual electricity costsProduction 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. Thenon 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).Maphobeni Farmers Association Report - 2009 Page - 48 -

6 . 2 M a n a g e m e n t P r a c t i c e sDifferent Soil TypesThe different soils (Lesibovu, Rondspring, and Somerling soil series) on which the project isdeveloped have different water holding properties and require different irrigation patterns.However, only one irrigation pattern is implemented by this FA. Irrigation stand time andirrigation cycle must be calculated based on individual soil properties. Block I for example, ison top of a small hill and its soil are significantly deferent than the rest of the scheme. Thesesoils have a lot of rock outcrops (figure 24). Otherwise, Maphobeni irrigation scheme is ongood soils.Figure 24. Block I soilsSchedulingEffective scheduling ensures that the correct amount of water is applied at the right time andthe correct place. As a scheduling method Maphobeni Farmers Association is using the giveand take method. This method utilizes long term evaporation means and rainfall is accountedthrough rain gauge readings. There is no scheduling tool to accurately determine the amountof water to be applied with every irrigation.Results from the discharge test were used to calculate the amount of water applied to thecrop. The following schematic was developed for phase one irrigation system;Given:8 hours every 6 daysThus: 8 Standing time (hours)6 Cycle length (days)Maphobeni Farmers Association Report - 2009 Page - 49 -

Already calculated: Xg = 4.7 mmThus: hours x Xg every 6 daysThus: 37.4 mm 6 daysGross mm per day = 6.2 mm/dayThus: Net mm per day = 4.7 mm/dayBased on this observation the irrigation pattern adopted by Maphobeni does not meet the6.5mm/day recommended sugarcane irrigation requirements. This FA is therefore, underirrigatingThe same irrigation pattern implemented in phase one is used in phase two and again theresults reflect that sugarcane irrigation requirements are not meet.Given:8 hours every 6 daysThus: 8 Standing time (hours)6 Cycle length (days)Already calculated: Xg = 3.94 mmThus: hours x Xg every 6 daysThus: 31.5 mm 6 daysGross mm per day = 5.3 mm/dayThus: Net mm per day = 3.9 mm/dayIf the irrigation cycle is reduced to 4 days or the standing time increased to 24 hour netapplication rate would increase to at least 6.5mm/day.Training of farm manager and his assistantsSwaziland Sugar Association and Ubombo Sugar provide technical assistance to this FA butbased on the current condition of the irrigation system, more is still to be done. More focushas to be put into training this FA on operation and maintenance of the irrigation system andensure that equipment is replaced with correct ones and by qualified technicians. Farmers donot have the required expertise on irrigation matters and end up making expensive mistakes.This FA is not in the position to rectify mistakes hence they live with the results of onineffective operation and management regimes currently implemented. This capacity buildingexercise will go a long way into improving efficiency in this irrigation project.Maphobeni Farmers Association Report - 2009 Page - 50 -

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 system.Table 7. 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 and nozzles where necessaryXXXXFlush mainlinesXTable 8. Maintenance practices implemented by FAMonitor Results ClassificationInspect the system for leakages Daily AcceptableCheck system pressure and system flow Never UnacceptableService air valves and hydrants Attend to fault UnacceptableCheck sprinklers for wear and replace springs, washersand nozzles where necessaryNeverUnacceptableFlush mainlines Never UnacceptableThe following is a list of items that require urgent maintenanceIntake sump requires urgent attentionThe balancing dam is leakingPump and mechanical control valveInstallation of vacuum gauges and one pressure gauge before pump control valvesReplace all damaged and hardened gasketsReplace all worn male and female pipe fittingsMaphobeni Farmers Association Report - 2009 Page - 51 -

Attend to leakages in air valves, mainlines and hydrantsReplace all draglines that have more than three jointsReplace leaking and corroded hydromatics, pipelets, and sprinkler standsReplace plastic with brass, correctly sized and identical nozzlesReplace old and worn out sprinklers with the correct type of sprinklerFix malfunctioning scour valves.Hydromatics that burnt during harvesting must be replacedMaphobeni Farmers Association Report - 2009 Page - 52 -

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.River pump station:‣ A proper intake structure was not constructed on phase one pump station. The suctioninlets (foot valves) are suspended at the end of the Usuthu River. The foot valves are notprotected in any way and are intermittently in direct contact with the bottom of the channeland debris carried with the river water.‣ Phase two river pump station, on the other hand, has an improperly constructed sump.During operations, the pumps suck debris like mud and sand which affect pumpperformance and the lifetime of the pumps.‣ Suction pipe flow velocity for these pumps through the 200mm suction pipe in PS 1exceeded the 1,5m/sec maximum allowed in norms - causing pump cavitations hencefrequent wearing of impellers and high maintenance cost.‣ Incorrectly sized fittings in suction and delivery manifolds of all pump stations affectsystem performance. The effects of these are severe on the eccentric reducer because itis directly attached to the pump and the sudden restriction in size increases turbulenceoccurrences and cause irregular feeding of the pump hence cavitation. With such aninstallation wearing and maintenance cost of the pump will increase.‣ The evaluation of pumps could not identify whether the pumps are optimally operating ornot because of the absence of flow and on some pressure measuring devices.‣ The water depth above the suction inlet was measure to be less than the acceptedminimum water depth according to suction pipe flow velocities. This reduces pumpefficiency and performance.‣ Based on the duty point of the installed ETA 125-50/2 phase one pump, a smaller andcheaper ETA 100-250 single stage pump could have been used. Pressure measurementsresults reflected that this pump is operating below the design duty point.‣ Pressure requirements from the balancing dam to the critical sprinkler in phase two areestimated at 90m. The impellor diameter of these pumps is 246mm and in order for thesepumps to generate the required pressure a 255mm impellor diameter must be installed inthese pumps.‣ High speed pumps are used in phase two booster pump stationMaphobeni Farmers Association Report - 2009 Page - 53 -

‣ Phase two pump stations are well designed and constructed with ample working spaceand ventilation.‣ The balancing dam is leaking and reduced the conveyance efficiency of the irrigationsystem.‣ There is no mechanism to regulate flow between river pumps and booster pumps.‣ All pumping units in Maphobeni are not serviced but repaired as faults develop.MAIN LINE‣ No information was available on mainline pipe sizes, lengths and class and because thereare no pressure measuring points on hydrants, friction loss through the mainline could notbe calculated. An undisputed conclusion, therefore, on whether the supply system wascorrectly designed or not cannot be drawn until details on pipe size, pipe classes, anddistances occupied by the different sizes are obtained.‣ Pipe bursts are one major indicator of under-specification in pipe classes and recurrentpipe breakages were experienced only in phase one mainlines, sub-mains and laterals.‣ The mainline has a leak and this reduces system pressure and flow hence theunacceptable flow and pressure variation.‣ Some Air valves and sections of mainlines are leaking – overall system efficiencycompromised.SPRINKLER INFIELD IRRIGATION‣ The lateral of the irrigation system that was installed by S.I.I. (phase two) are equippedwith mechanically chocked hydraulic valves. Pressure-regulating pilot are not installed.Phase one laterals are equipped with mechanical valves; there are no hydraulic valves inthis phase.‣ This dragline irrigation system is installed with 108m lateral spacing (phase 2) and 216mlateral spacing (phase 1). Emitter spacing is maintained between 17m - 20m.‣ Pressure variation in this irrigation system is at 65.71% for phase one and 50.15% forphase two. The average system operating pressure is 350.1kPa and 299.09kPa for thetwo phases respectively. Not only is pressure variation is above the recommendedmaximum of 20%, but phase two average sprinkler operating pressure is below therequired 350kPa sprinkler pressure.‣ Flow variation was above the recommended maximum of 10% averaging a high of45.86% and 51.24% in the two phases respectively. The average sprinkler application forMaphobeni Farmers Association Report - 2009 Page - 54 -

phase one and two was found to be 1.51m3/hr and 1.28m3/hr respectively; instead of1.4m3/hr stipulated in the Swaziland sugar industry standards.‣ The average GAR for Maphobeni phase 1 irrigation is 4.2mm/hr and 3.9mm/hr for phasetwo. The recommended GAR is 4.2mm/hr and this means that Maphobeni FA is slightlyunder-irrigating phase two Three sprinkler packages with identical nozzle sizes wereidentified‣ Sprinklers were not equipped with pressure regulators and were running on differentpressures and deliveries.‣ 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.‣ Phase one of the irrigation system was installed in 1994, almost 19 years ago, and asyears elapsed, system efficiency reduces due to equipment wearing out‣ Measurements of the amount of sprinkler nozzle wear (mm) taken from phase 1 and twoblocks averaged 3.2% and 5.5% respectively. Nozzle wearing was on maximum 12% inboth phases.‣ S.I.I. dragline irrigation system was installed in such a way that all laterals have individualhydraulic valves. These hydrants are equipped with Gulf hydraulic valves but withoutpilots for pressure regulation. A mechanical choke was installed on the valve headinstead.‣ No drainage was planned with the development of this project and large waterloggedareas appeared at some areas.OVERALL MANAGEMENT AND MAINTENANCEOperations‣ Financial viability for smallholder grower‣ High Interest Rates‣ Electricity cost high‣ High Transport costs‣ High Production CostsMaphobeni Farmers Association Report - 2009 Page - 55 -

Management 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.‣ No scheduling measurements were followed and under the current irrigation pattern theirrigation system cannot 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.Maintenance‣ Without an operation and maintenance manual, management have difficulty in operatingand maintaining the system. Incorrect operation procedures are followed and impropermaintenance schedules adopted.‣ 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 maintaining them.Maphobeni Farmers Association Report - 2009 Page - 56 -

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 divide therecommendations into four categories namelyA. Immediately: This must be done directly after harvesting.B. Short term: This must be done this seasonC. Medium term: This must be done before replantD. Long term: This must be rectified with replant.Pump StationsImmediately:‣ Get all river running to full capacity i.e. installing a bigger impellor on phase two boosterpumps E 50 000.00‣ Repair all faulty equipment. E 20 000.00‣ Install safety mechanisms on all pumping units E 25 000.00‣ Establish arrangement with a reliable contractor to assist with the maintenance of allequipment.Short term:‣ Do routine maintenance on pumps and all equipment. E 20 000.00‣ Reduce suction flow velocities by increasing the size of the suction manifold. E 10 000.00‣ Replace all incorrectly dimensioned fittings (bends and reducers) on the suction anddelivery manifold with the correct size E 10 000.00‣ Refurbish pump houses i.e. finishing all civil works, improving floor drainage, etcE 50 000.00‣ Replace all phase one pump with new generation highly efficient pumps E 80 000.00‣ Install flow meters in all pump stations E 80 000.00Medium term:‣ Construct a proper intake structure (sump) at phase one river pump station andrehabilitate phase two sump and dam off-take to the booster pump station E 350 000.00‣ Seal all leaks in balancing dam E 150 000.00Maphobeni Farmers Association Report - 2009 Page - 57 -

Long term:‣ Replace all high speed pumps with low speeds E 75 000.00MAIN LINEImmediately:‣ Do routine maintenance on all equipment. E 2 500.00‣ Implement soil and water conservation measures to stop/ minimise soil erosion E 10000.00‣ Fix all leaking air valves, installed additional air valves, attend to leaks on mainline, etcMedium term:‣ Confirm pipe sizes, pipe classes, lengths and orientation of the mainline. Redesign andreinstalled all mainlines that do not conform to norms E 100 000.00‣ Install additional air valves E 7 500.00SPRINKLER INFIELD IRRIGATIONImmediately:‣ Fix all damaged sprinkler stands and replace leaking draglines and other malfunctioningequipment E 10 000.00‣ Equip all sprinklers with pressure regulators. E 60 000.00‣ Replace all worn out sprinkler nozzles E 5 500.00Short term:‣ Replace all mechanical chokes and install pressure regulating pilots in hydraulic valvesE 50 000.00‣ Redesign and install at least 54m spaced hydraulically controlled laterals with 20 meterslong draglines in phase one. E 450 000.00Long term:‣ Replant all blocks that perform badly E 80 000.00‣ Install sub-surface and/or surface drain in bad soils E150 000.00Maphobeni Farmers Association Report - 2009 Page - 58 -

OVERALL MANAGEMENT AND MAINTENANCEManagement‣ 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.‣ A consortium could be formed for the sugarcane growing industry to have a muscle wherebuying of farm inputs is concerned. This could reduce production costs‣ Adopted a proper scheduling strategy.‣ The water allocation of 4 cusecs is not enough for this developmentMaintenance‣ 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 6.5mm/day net application, i.e.changing from a 6 to 4 day cycle at the implemented 8 hour standing time.‣ Establish arrangement with a reliable establishment to assist with the repair andmaintenance of all equipment.‣ Replace all old equipmentMaphobeni Farmers Association Report - 2009 Page - 59 -

9 C O N C L U S I O NMaphobeni Farmers association was developed in two phases between 1994 and 2002. Thefirst phase was 56 hectares dragline system with 216m spaced laterals, 100m draglines andwas designed for maize production by A.J. Nyman. Phase two was designed andimplemented in 2002 by SII. This phase is 95Ha comprising of a river pump station, abalancing dam and a booster pump station. Laterals in are about 108 meters apart with 50mdraglines.Maphobeni irrigation was implemented mostly on good soil and their yields are, on average,130 tonnes per hectare for phase two and 120 tonnes per hectare for phase one. Anundisputed conclusion, as to whether this irrigation system was correctly designed or notcould not be drawn pending confirmation of pipe sizes, classes and orientation. But sitemeasurements revealed that phase two is acceptably designed except a small diameterimpellor is installed in booster pumps. Phase on the other hand is characterized by profuseleaks, high pressure losses along the long dragline, unacceptable flow and pressurevariation, etc. There is an urgent need to improve irrigation efficiency on both phases thusincreasing productivity of this scheme. The following was recommended;1. Rehabilitate all pump stations ensuring optimum and efficient performance of pumps andmotors at a cost of approximately E 90 000.00. This cost includes reducing suction flowvelocities by increasing the size of the suction pipe, and replacing all incorrectlydimensioned fittings (bends and reducers) on the suction and delivery pipes.2. Redesign and install at least 54m spaced hydraulically controlled laterals with 20 meterslong draglines in phase one. Mechanical chokes must be replaced with pressureregulating pilots in all phase two hydraulic valves. These will cost approximately E500.000 and has to be done immediately.3. Currently Maphobeni does not meet the crops irrigation requirements. An irrigationpattern that will result into a 6.5mm/day net application must be adopted. For example,reducing the 6 days cycle to 4 days with the 8 hour standing time.4. Strengthen training of FA on operation and maintenance of irrigation system. This willinvolve the compilation of an operation and maintenance manual to assist in theimplementation of a proper maintenance and operation strategies.Maphobeni Farmers Association Report - 2009 Page - 60 -

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 the Performanceof two Types of Irrigation Emitters executed on behalf of the water Research 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 Row Crops.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 forAgricultural Engineering. Republic of South Africa.12. Solomon K.H. 1988a, Irrigation Systems and Water Application Efficiencies. Centrefor Irrigation Technology, California State University, Fresno, California.Maphobeni Farmers Association Report - 2009 Page - 61 -

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. Zoldoske, D.F. and Solomon, K.H. 1988. Coefficient of Uniformity- What it tells us.Center for irrigation Technology, California State University, Fresno, California.Maphobeni Farmers Association Report - 2009 Page - 62 -

11 P R O D U C T I N F O R M A T I O NMaphobeni Farmers Association Report - 2009 Page - 63 -

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Soils classification according to SSAMaphobeni Farmers Association Report - 2009 Page - 74 -

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12 A P P E N D I C E SAttached are the following documentsAppendix 1: SEB usage for pump stationsAppendix 2: capital recovery factors (CRF)Maphobeni Farmers Association Report - 2009 Page - 76 -

SEB usage for River pump station Phase2Annual WaterWater requirement use 14000m³/Year 95 Total water use in year 1330000 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 monthmain107730102410131404 120897 116907 65968 38038 72219 122094 152950 158935 140448Water use per hour 150 142 183 168 162 92 53 100 170 212 221 195Main pumps Needed 0.8 0.8 1.0 0.9 0.9 0.5 0.3 0.5 0.9 1.1 1.2 1.0River Pumps practical 2 2 2 2 2 1 1 1 2 2 2 2kW use for Main Pump 61.26 61.26 61.26 61.26 61.26 61.26 61.26 61.26 61.26 61.26 61.26 61.26Total kVa Demand 245.04 245.04 245.04 245.04 245.04 122.52 122.52 122.52 245.04 245.04 245.04 245.04Total kw use for themonth35103.933370.442818.139394.4238094.2721495.7412394.7223532.6439784.46 49838.9251789.1445765.13Total Max. Demandcosts17010.717010.717010.717010.6817010.688505.3388505.3388505.33817010.6817010.67717010.6817010.68Total kW cost7722.877341.499419.99 8666.77 8380.74 4729.06 2726.84 5177.18 8752.58 10964.5611393.6110068.33Total Energy Cost /month24733.524352.226430.725677.4525391.42 13234.411232.1813682.5225763.2627975.23928404.2927079.01273956.1SEB usage for Booster pump station Phase 2Annual WaterWater requirement use 14000m³/Year 95 Total water use in year 1330000 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 10.56Maphobeni Farmers Association Report - 2009 Page - 77 -

Watter use per monthmain107730102410131404 120897 116907 65968 38038 72219 122094 152950 158935 140448Water use per hour 150 142 183 168 162 92 53 100 170 212 221 195Main pumps Needed 0.8 0.8 1.0 0.9 0.9 0.5 0.3 0.5 0.9 1.1 1.2 1.0Booster Pumps practical 2 2 2 2 2 1 1 1 2 3 3 2kW use for Main Pump 49.6 49.6 49.6 49.6 49.6 49.6 49.6 49.6 49.6 49.6 49.6 49.6Total kVa Demand 198.4 99.2 99.2 99.2 99.2 99.2 99.2 99.2 99.2 99.2 99.2 99.2Total kw use for themonthTotal Max. DemandcostsTotal kW costTotal Energy Cost /month14211.213772.93126.4616899.413509.46886.462972.079858.53 1070017334.115948.1115421.7717404.3210035.5619053.5216106.0213450.92213977.2618527.186886.4 6886.46 6886.46 6886.46 6886.46 6886.46 6886.466886.46 6886.466 4 4 4 4 4 4 6886.464 4 43813.51 3508.59 3392.79 3828.95 2207.82 4191.78 3543.32 2959.20 3075.00 4075.9810395.0 10279.2 10715.4 9094.28 11078.2 10429.7 9845.666 9961.465 5 2 7 4 9 8 210962.44130219.5Maphobeni Farmers Association Report - 2009 Page - 78 -

Appendix 2: capital recovery factors (CRF)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 0.160Maphobeni Farmers Association Report - 2009 Page - 79 -