Service Contract No 2007 / 147-446 - Swaziland

LIST OF FIGURESFIGURE 1. PUMPING STRUCTURE IN THE USUTO RIVER ...................................................................................... - 2 -FIGURE 2. SAND TRAP STRUCTURE NEXT TO THE BOOSTER PUMP STATION ...................................................... - 3 -FIGURE 3. THE INSIDE OF THE BOOSTER PUMPHOUSE. ....................................................................................... - 4 -FIGURE 4. MCC FOR ALL THE PUMPS ................................................................................................................... - 4 -FIGURE 5. SAPWAT SCREEN INDICATING WATER REQUIREMENT FOR SPRINKLER IRRIGATION WITH RAINFALLTAKEN INTO ACCOUNT ................................................................................................................................ - 9 -FIGURE 6. REQUIRED RADIUS OF 90 BENDS (SOURCE: ARC (2007)) .................................................................. - 13 -FIGURE 7. 250MM 90° BENDS IN BULK WATER MAINLINE ................................................................................ - 14 -FIGURE 8. 250MM 90° BENDS ON DELIVERY PIPE OF BOOSTER PUMP 1 AND 2 ............................................... - 15 -FIGURE 9. CONCENTRIC AND ECCENTRIC REDUCERS ......................................................................................... - 15 -FIGURE 10. CORRECT INSTALLATION OF ECCENTRIC REDUCERS ON BOOSTER PUMPS .................................... - 16 -FIGURE 11. SPACING AND PLACING OF SUCTION PIPE INLETS........................................................................... - 17 -FIGURE 12. DIVERSION CANAL TAKEOFF AT THE USUTHU RIVER ...................................................................... - 17 -FIGURE 13. BOOSTER PUMPS INTAKES INSIDE A HALF EMPTY CONCRETE RESERVOIR .................................... - 18 -FIGURE 14. MINIMUM WATER DEPTH ABOVE SUCTION PIPE INLET ................................................................. - 18 -FIGURE 15. ATMOSPHERIC PRESSURE VS. HEIGHT ABOVE SEA LEVEL ............................................................... - 20 -FIGURE 16. RIVER PUMP AND MOTOR .............................................................................................................. - 22 -FIGURE 17. MAINLINE SECTION UNDER REPAIR ................................................................................................ - 28 -FIGURE 18. LATERAL ISOLATION VALVES ........................................................................................................... - 29 -FIGURE 19. MEASURING APPARATUS FOR SPRINKLER NOZZLE SIZE ................................................................. - 31 -FIGURE 20. FLOPPY SPRINKLER BLOCK HYDRANT VALVES ................................................................................. - 33 -LIST OF APPENDICESLobuvu Farmers Association Report - 2009Page vi

Appendix 1: SEB usage for river pump stationAppendix 2: Capital recovery factors (CRF)Appendix 3: Soil map and block layoutABBREVIATIONSLobuvu Farmers Association Report - 2009Page vii

AbbreviationAEARCASAECUCVDUEACEUFAGARHDPEMCCNARNPSHPVCRSSCSABISESSASWADEUsDescriptionApplication 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 UniformityLobuvu Farmers Association Report - 2009Page viii

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 TLobovu Farmers Association is constituted by 41 members but only 31 remain by the dateof this evaluation, and has a total irrigated area of 88.1 hectares but 96 are currentlyplanted. Their sugarcane is comprised mainly of N23, N25 and N19 varieties givingapproximately 99 tonnes per hectare with 13% sucrose last production season.The project‣ This project was implemented in one phase by D & J Investment in 1997. This phasewas a dragline irrigation system.‣ A river pump station in the Usuthu River with two submersible pumps pump water to abooster pump station on the bank of the river. Two Wkln 150/4 pumps pump the waterto the fields that are situated on the first ridge on the road to St Phillips.Figure 1. Pumping structure in the Usuto River‣ A 300mm mainline conveys bulk water from the river pump into the reservoir. Thisreservoir is used for both irrigation and for homesteads water.Lobuvu Farmers Association Report - 2009 Page - 2 -

‣ Adjacent to the pump house, are a structure that serve as a sand trap.Water arechannelled to the pump position by a cannel that constantly block by sand from theriver.‣ However during the time of evaluation one was found to be in operation whilst theother one was removed.Figure 2. Sand trap structure next to the booster pump station‣ The booster pump station is well constructed building but were neglected over theyears and is in a bad state..‣ The air valve of the system was found to be leaking at a high rate.‣ The pump house was found to be well drained as it was able to flush out waterdroppings out off the pump house at a recommendable manner.‣ No water measuring device was installed.‣ The pump station is proximally 2 km from the fields and is very difficult to manageover this distance.Lobuvu Farmers Association Report - 2009 Page - 3 -

Figure 3. The inside of the booster pumphouse.‣ Water is distributed to the field by a network of PVC and poly pipes with hydraulicisolating valves at each irrigation block.‣ The Motor Control Centres (MCC) of both pumps is well designed and installed.Figure 4. MCC for all the pumpsLobuvu Farmers Association Report - 2009 Page - 4 -

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 GeneralDesign information from the designer and from the client representative during construction,RSSC could not be obtained. The design was therefore checked against Swaziland sugarstandards 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:CropDesign irrigated areaGross ApplicationNet ApplicationIrrigation CycleSprinkler dischargeSprinkler SpacingSugarcane88.1 Ha52mm39mm6 Days0.39l/s18 m x 18 mApplication Efficiency 75%Stand TimeGross PrecipitationAnnual Irrigation hours12 hours (depending on soil)4.33 mm/hour3 300 hoursLobuvu Farmers Association Report - 2009 Page - 5 -

3.1.1.3 Review of Irrigation Design Criteria and Specifications3.1.1.3.1 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 of theproject.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 Lobovu Farmers Association1 GENERAL INFORMATION1,1 Owner Lobovu Farmers Association1,2 Farm Name - Number - Co-ordinates Swazi nation land1,3 Telephone number1,4 Area developed 88.1 Ha1,5 Water Allocation 88.1 l/s2 CLIMATE2,1 Month state Jan2,2 Weather station state Ubombo2,3 Evaporation mm/day 7mm A-Pan or 5mm Grass Factor3 MANAGEMENT3,1 Available working days per week days 73,2 Available working Hours per day hours 244 CROP BLOCK NO Lesibovu/Shortlands Betusile/Dundee4,1 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 AugustLobuvu Farmers Association Report - 2009 Page - 6 -

5 SOIL Lesibovu/Shortlands Betusile /Dundee5,1 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 220.62 257.409 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 1Lobuvu Farmers Association Report - 2009 Page - 7 -

11PRACTICAL 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 6 Day0606,0018,00Day 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 FellowLobuvu Farmers Association Report - 2009 Page - 8 -

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 5. SAPWAT screen indicating water requirement for sprinkler irrigation with rainfalltaken into accountSoil informationSoil properties used when compiling the afore schedule was obtained from the below charts.These are the three major soils found within the farm, an outline of which is shown on a soilmap attached in annexes.Lobuvu Farmers Association Report - 2009 Page - 9 -

Lobuvu Farmers Association Report - 2009 Page - 10 -


4 F I E L D E V A L U A T I O N O F I R R I G A T I O NS Y S T E M4.1.1 P u m p s and 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 and collection of air in high places in the suction pipe, is prevented. Inview 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 / s2dWhere: V = flow velocity in pipe (m/s)Q = flow rate (m³/h)d = inner diameter of suction pipe (mm). ………………………………….… (1)RIVER PUMP STATIONSOne Hidrostal submersible axial flow pump is installed in this river pump station and deliverswater into a concrete reservoir adjacent the booster pumps station. There is no designinformation for this irrigation system and details of the motor could not be gathered. Forpurposes of this evaluation pump discharge was estimated by getting the multiply of the totalirrigated area (96 ha), industry norms of 2.57 sprinklers per hectare, 1.4m³/hr sprinklerdischarge and 10% safety factor for pump discharge. This pump must therefore generate, atleast 379.95m³/hr (inclusive of 10% safety for pump discharge) of flow to meet irrigationrequirements. The flow velocity through the pump inlet could not be measured because thedimensions and specification of this pump could not be confirmed; otherwise it must notexcess 0.4m/sLobuvu Farmers Association Report - 2009 Page - 12 -

BOOSTER PUMP STATIONWater is pumped from the river pumps into a concrete reservoir adjacent to is another pumpstation housing two KSB WKLn 150/4 pumps. These pumps are installed in such a way thatthe impellor eye is below the minimal water level in the reservoir, which ensures that there isalways water in the pump casing and suction pipe. These pumps are interconnected and thedesign flow of these pumps, taken from the calculation of river pumps is 190m³/hr per pump.Information on whether this pump was designed for future expansions or with only one pump(380m³/hr pump flow) and the second as a backup could not be ascertained and theassessment can not be conclusive.Both these pumps are connected to the reservoir by a 300mm steel suction manifold andoperating at the calculated pump flows above the flow velocity through the suction pipe is0.75m/s for the former and 1.5m/s for the latter. According to the Agricultural ResearchCouncil, ARC (2007) the ideal suction pipe flow velocity must be 1.0 m/s, but suction pipeflow velocities up to 1.5 m/s are acceptable. High suction flow velocity in the suction pipecaused turbulence in the pipe, thus causing irregular feeding of the pump (and eventuallycauses cavitation). As a result impellor wearing is excessive and thus explains the poor.4.1.1.1.2 Requirements for Fittings90º BendsThe radius (mm) of a 90º bend must be, at least, as shown in Figure 2rdFigure 6. Required radius of 90 bends (source: ARC (2007))r 2d100mm …………………………………... (2)Lobuvu Farmers Association Report - 2009 Page - 13 -

Where: r = radius of bend (mm)d = inner diameter of suction pipe (mm).RIVER PUMP STATIONThe flood lifter is submersible and has no suction pipelines. Two 250mm 90° bends areconnected to the delivery side of this pump, on the bulk water mainline. These have radiusesshorter than the required minimum but because these are on the delivery manifold and thatthere is more than five times the delivery pipe size diameter pipe further on from the pumpoutlet; the effects of the incorrect sizes are insignificant.Figure 7. 250mm 90° bends in bulk water mainlineBOOSTER PUMP STATIONThe two pumps are each equipped with one 90° bend on the delivery mains. All these bendshave a smaller radius than specified by equation 2 above. This incongruity has insignificanteffects on pump performance.Lobuvu Farmers Association Report - 2009 Page - 14 -

Figure 8. 250mm 90° bends on delivery pipe of booster pump 1 and 2ReducersThe 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 were evaluated against equation 3 below, adoptedfrom the ARC (figure 4).Figure 9. Concentric and eccentric reducers ( d ) ………………………... (3)52d1Where: = length of the reducer (mm)d1 = smaller inner diameter (mm)d2 = larger inner diameter (mm)Lobuvu Farmers Association Report - 2009 Page - 15 -

BOOSTER PUMP STATIONThe 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). Eccentricreducers were installed on the suction side and concentric reducers on the delivery side, asper the requirement. All investigated eccentric reducers were installed with the straight sidetowards the top, to prevent air collecting in the pipe and causing cavitation (figure 8). Thelengths of both eccentric and concentric reducers were evaluated against equation 3 below,adopted from the ARC (Figure 3).Figure 10. Correct installation of eccentric reducers on booster pumpsBoth eccentric and concentric reducers on both booster pumps are incorrectly dimensioned.The incorrectly dimensioned eccentric reducer affect pump performance substantiallybecause it is directly attached to the pump 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. The unacceptabledimensions of the concentric reducer had negligible effects on the performance of the pumpand the entire system.Lobuvu Farmers Association Report - 2009 Page - 16 -

4.1.1.1.3 Suction Pipe InletsSpacing and placing of suction pipe inletsIn a well constructed sump the inlet of the suction pipe must be in accordance to therequirements of at least 0,5d (d = inner diameter of the suction pipe) from the bottom of thepump sump (figure 6) and at least 1,5d away from the side of the pump sump.1.5dd0.5dd3d 3d 1.5dFigure 11. Spacing and placing of suction pipe inletsAn intake sump was constructed for the Hidrostal Axial flow submersible pump on the banksof the Usuthu River. This intake sump is supplied by a diversion canal from the recedingUsuthu River. This canal is currently out of structure and ineffective in catching the fluctuatingUsuthu River hence brings more problems than solutions to the operation of the system.Figure 12. Diversion canal takeoff at the Usuthu RiverLobuvu Farmers Association Report - 2009 Page - 17 -

Both booster pumps are supplied by a concrete reservoir and at optimum level the waterdepth above the foot valves is 800mm. According to the graph above, and the suction flowvelocities of all booster pumps, the recommended minimum water level above suction inletswas contented. The reservoir water level should not be allowed to decrease below 1 meter.Below this level vortex will form thus reducing pump performance.Figure 13. Booster pumps intakes inside a half empty concrete reservoirFigure 14. Minimum water depth above suction pipe inletLobuvu Farmers Association Report - 2009 Page - 18 -

4.1.1.1.4 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 factorQ = flow rate in the fitting (m³/h)d = inner diameter of the fitting (mm)A summation of friction loss across the booster pump’s foot valve, and suction pipe gave atotal hf of is 0.15 meters. The river pump is a submersible pump and is not connected to asuction pipe. Friction in the suction pipe has a direct effect of maximum suction height andconsequently the available net positive suction head (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) – figure 15hf = suction side losses (friction losses and secondary losses in fittings, m)hvp= vapour pressure of water (m)NPSH required = net positive suction head from the pump curve (m)Lobuvu Farmers Association Report - 2009 Page - 19 -

Figure 15. Atmospheric pressure vs. height above sea levelRiver Pump StationThe impellor of this river pump is positioned inside the intake sump. There is positive suctionhence installation of this pumping unit is within the ARC (2006) recommendation of NPSHr

Table 1. pump and motor specifications and measurements conducted on all pumpsPUMP SPECIFICATIONS FROM INFORMATION PLATE AND MEASUREMENTSRiver Pump Station Booster Pump StationsMake / model Hidrostal WKLn 150/4Number of units 1 2Pump duty point 380m³/hr , 15m 380m³/hr , 142mImpeller diameter mm - FSPressure under normal operation (H) m - -MOTOR SPECIFICATIONS FROM INFORMATION PLATE AND MEASUREMENTSModel and type - -Power (P motor) kW - -Power factor (cos ø) - -Speed rpm - -Current (measured) A - -Voltage (measured) V - -4.1.1.2.1 Pump OperationBoth the river and booster pumps were not in operation during the evaluation. the mainlinehad a leak and was under repair. The system has been off for more than two weeks. Apartfrom this anomaly there is no flow meter and pressure gauges to monitor pump performance.4.1.1.2.2 Power required on the pump shaftThe power required on the pump shaft was calculated as soon as the total pump head anddelivery was calculated. The pump duty points of both the river and booster pumps are shownin table 1 above and the power required on the pump shaft was calculated with the followingformula and establishes whether 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 (%)Lobuvu Farmers Association Report - 2009 Page - 21 -

The design duty point of Lobovu pumps is not know but was estimated as shown in table 1above with 23.9kW and 188.5kW for the two pump stations respectively. According the ARC(2007), the power output of the motor must be 10-15% greater than the power required on thepump shaft giving a motor size of 30kW for the submersible river pump and 225kW forbooster pumps. Even though the installed motor sizes could not be confirmed but they are notof this size. If these pumps were designed to operate simultaneously (without a backup) therequired power reduces to 132kW. These results are summarised in table 2 below.The required power, Prequired, of this pump was to be compared with the output power of theelectric motors obtained from measurements of voltage and current. The pumps were notoperating; hence this evaluation could not be carried out. According to the ARC theconfiguration of the different power units must conform to the expression Pu = P < Pmotor.4.1.1.2.3 Pump Station General EvaluationRiver Pump Station‣ This pump station was designed for two pumps and currently one is installedFigure 16. River pump and motor‣ The access ladder into this pump is too steep and corroded. In fact the entire pump housestructure is falling apart.‣ This pump was not running. It was reported that the pump trips especially at highatmospheric temperature.Lobuvu Farmers Association Report - 2009 Page - 22 -

‣ There are no operational and maintenance instructions for this pump.‣ There is no shelter for the pump and MCC‣ Electricity cables supplying the pump are exposed and not acceptable protected. Theseare dangerous to both human and animals‣ The river intake sump is not protected from storm water and/or flooding. Sand and debricarried with runoff water are deposited into the sump.Booster Pump Station‣ Motors of both pumps do not have information plates. It almost impossible to identify thecapacity of these motor.‣ The pump station is dilapidated and there is no one interested on looking after the pump.The main reason cited was that this pumping unit will soon be vacated and a newlyconstructed earth dam will be used instead.‣ The pump station is hazardous and unhygienic‣ Electric cables are all over the place and are not well anchored and not protected‣ There is no floor drainage infrastructure, insufficient light, no working space between thepumps, and the pump station is not secured enough.‣ Pump and motor protective mechanisms need to be improved‣ MCC panels have malfunctioning meters and there is no electric cable racking.Pumps 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 straightLobuvu Farmers Association Report - 2009 Page - 23 -

edge 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 pump and that meant the unit wassquarely 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).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 are confined to energy costs and maintenance(excluded labour. Admin etc).Interest rate: 10%Useful life (this analysis)Infield irrigation (Tape etc):10 yearsLobuvu Farmers Association Report - 2009 Page - 24 -

PVC/Poly pipe:Filters:Pumping equipment and electrics20 years15 years15 yearsMaintenanceInfield irrigation: 3%Distribution - pipelines: 2%Pumping plant: 1%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 pointNo motor sizes could be found therefore no EAC calculation could be made4.1.3 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 for each 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;dkQ0.37i …..……………………….……… (8)Where: di = inside diameter of pipe, mmK= constant derived from annual irrigation hoursQ= flow rate (m 3 /h)Lobuvu Farmers Association Report - 2009 Page - 25 -

Bulk Water MainlineFor annual irrigation hours of 3300, adopted by the sugar industry, the most economical pipesize diameter for the bulk water pipeline from the river pump station to the storage reservoirwas calculated for an ultimate system flow of 380m³/hr. At this flow rate the most economicpipe size is 254.86mm corresponding to a nominal pipe size of 315mm.Site investigation revealed that the Hidrostal submersible pump delivers to a 250mm steelbulk water mainline 103 meters in length. This section is under-designed.Irrigation MainlineThe delivery pipelines from the two pumps are interconnected hence during breakages and/ormaintenance one pump can be used in place of the other. The outlets of each of these pumpsare connected to a 300mm main delivery manifold adapted to 315mm PVC. Considering the96 hectares that is under production, these pumps must generate 380m³/hr and the mosteconomic pipe size diameter is, just like the bulk water mainline, 254.86mm (ID) or 315mm(OD). This mainline is thus correctly designed; however, pipe sizes, classes and orientationdetails of this irrigation system could not be obtained.4.1.3.2 Mainline classFriction loss and required system pressure was used to determine pressure in variouspositions of the pipeline, according to which a suitable pipe class was determined. A hydraulicgradient (a line connecting the initial pressure to the end pressure) was drawn for the original(design) mainline. Static and dynamic conditions were studied to enable sensible and safepipe class selection.Details on pipe class, size and orientation could not be obtained so an undisputed conclusionas to whether pipe class selection is in accordance to SABI norms or not can not be drawn.With 142m pump pressure a class 16 pipe should be installed form the pump stationgradually reducing towards the fields.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 nThe required total head of the pumps was calculated by summing the following and dischargerequirements calculated as indicated in previous sectionsFriction loss in the mainlineLobuvu Farmers Association Report - 2009 Page - 26 -

Static water level in reservoirThe pump suction headSecondary head lossesElevation change from booster pump house to critical sprinklerRiver Pump StationThe following was noted;‣ Based on the total irrigated area of 96 hectares (88.1 ha after the canal was built) thispump must generate at least 380m3/hr to meet irrigation requirement at approximately15m head. This duty point is within the operating range of the installed pump. At this dutypoint this pump must be powered by a 30kW motor.‣ The river pump model could not be gathered hence the capacity and the recommendedoperating range could not be ascertained‣ The diversion canal into this pump station is not effective in catching the receding UsuthuRiver. Half the pumping unit was exposed inside the intake sum and occasionally thesump runs empty. Sand accumulation along the canal and sump is one major drawback.‣ Because only one pump is installed, this could mean the system is operating at half itscapacity not unless the current pump is bigger than the initially installed pair.Booster pump station‣ Motors of both pumps does not have information plates hence their sizes could not berecorded. Also, the design duty point of the booster pumps could not be ascertained.‣ Just like in the case of river pumps system capacity was calculated for the total irrigatedarea to be 380m³/hr.‣ For the pumps to meet the recommended sprinkler operating pressure they mustgenerate at least 142m.‣ At this duty point the installed WKLn 150/4 pumps must be powered by 220kW 2-polemotors. This type of installation would mean the second pump is for backup purposes.Otherwise, considering both pumps pump duty reduces to 190m³/hr and 132kW sizemotor. The former is however outside the recommended operating pressure of the WKLn150/4. At this duty point this pump operates at low efficiencies, hence the WKLn 125/5 isrecommended.Lobuvu Farmers Association Report - 2009 Page - 27 -

5 F I E L D E V A L U A T I O N O F S P R I N K L E R I R R I G A T I O NS Y S T E MTable 2. Sprinkler valuated block summaryBlock Area (ha) 88.1Type of sprinkler systemDraglineName of DesignerD and J InvestmentName of contractorD and J InvestmentDesignMeasuredHydrant pressure (m) - -Sprinkler spacing (m x m) 18 18 – 24Lateral spacing (m) 90 91 -95Stand pipe height (m) 3 3Pressure regulator No NoDragline diameter (mm) 20 20Dragline length (m) 36 36-50A complete system evaluation could not be conducted because the irrigation system was shutdown. The mainline had a leak and was being attended; this problem has dragged for overtwo weeks.Figure 17. Mainline section under repairLobuvu Farmers Association Report - 2009 Page - 28 -

Hydraulic ValvesLaterals of this dragline irrigation system are connected to the mainline through a mechanicalvalve. There are no hydraulic valves yet for better performance these must be installedinstead and equipped with pressure-regulating pilots.Figure 18. Lateral isolation valvesThe installation of hydraulic valves equipped with pressure regulating pilots reduces a higherinlet pressure to a lower constant outlet pressure, regardless of fluctuating flow rates and orvarying inlet pressure. The pilot would sense down-stream pressure and modulates open orclose, causing the main valve to throttle, thus maintaining constant delivery pressure.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.Technical 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.Lobuvu Farmers Association Report - 2009 Page - 29 -

Table 3.Technical properties of sprinklers found on site at 35m operating pressureSprinkler Package Nozzle size Discharge (m3/hr) Wetted Radius (m)Rain bird 14070 3/16" nozzle 4.78 1.65 15.8Rain bird 14070 11/64" nozzle 4.37 1.39 15.2RC 140 11/64" nozzle 4.36 1.36 15.9Minimum Discharge (m 3 /hr) 1.47Maximum Discharge (m 3 /hr) 1.36Average Discharge (m 3 /hr) 1.65Flow variation (%) 19.77Two sprinkler packages with three different nozzle size combinations were identified asshown in table 3 above. Flow variation due to the different sprinkler – nozzle combinations, inboth phases is 19.77% which is higher than the ARC recommendation stating that thedifference in discharge in a specific irrigation block may not vary by more than 10% from theaverage discharge. The average application rate of the above combination is 1.47m³/hr and isabove the design application of 1.4m³/hr.This figure indicates that even on highly efficient pumping and supply system, irrigationefficiency will not improve, at least not until uniformity in this regard is obtained. This differentcombination has an effect also on the wetting diameter due to their different body trajectoryangles.Nozzle wearingThe only data that was possible to collect was sprinkler nozzle size to identify the amount ofwearing (mm) and sprinkler package – nozzle combination. An average of 3.7% increase innozzle diameter was recorded reaching a maximum of 4.4% in some blocks. The allowedmaximum increase of 5% in nozzle area means a 10% increase in flow and power demand,which relates to additional operating costs and over-irrigation. The ARC thereforerecommends sprinkler replacement if wear is greater than 5%. This irrigation system hasbeen operated for over 12 years and nozzle replacement has to be initiated.Sprinkler nozzles were measured with a specially machined apparatus (Figure 14)Lobuvu Farmers Association Report - 2009 Page - 30 -

Figure 19. 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. Mainly, these leaks are observedin sprinklers, sprinkler stand-dragline connections, broken dragline, pipelets, hydromatics,sub-mains, mainline, etc. it is important that all leaks are located quickly and repaired. A leakprevention program should include regular replacement of damaged draglines.Old AgeThe irrigation system was installed in 1997, 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.5.1.1 S p r i n k l e r p r e s s u r eThe optimal operating pressure (kPa) of the sprinkler should be between 60 and 70 times thenozzle diameter (mm). This is applicable to nozzles of 3 to 7 mm diameter (ARC, 2006).Lobuvu Farmers Association Report - 2009 Page - 31 -

Table 4.Optimal Operating Pressure Vs Nozzle Diameter for SprinklersNozzle diameterOperating pressure (kPa)Mm Inches x 60 x 701,591 / 16 "1,985 / 64 "2,383 / 32 "2,787 / 64 "3,181 / 8 " 191 2223,579 / 64 " 214 2503,975 / 32 " 238 2784,3711 / 64 " 262 3064,763 / 16 " 286 3335,1613 / 64 " 310 3615,5615 / 64 " 333 3895,9515 / 64 " 357 4276,351 / 4 " 381 445Gross application rate (GAR)The gross application rate (GAR) of the sprinkler was thereafter calculated, by means of thefollowing formula;GAR qe1000A ....…………………………………. (10) mm/hWhere; GAR = Gross Application RateA = wetted area (m 2 )The GAR is a fraction of emitter discharge and sprinkler spacing as indicated by equation 10above. The three nozzle size found in this development has a GAR of 5.09, 4.29, and 4.2mm/hr respectively. the recommended GAR for sugarcane is 4.2mm/hr. GAR can beimproved by ensuring that sprinklers operate at the recommended pressure/discharge,ensuring a lateral spacing of 18m, attending to leakages, ensuring the correct number ofsprinklers operate simultaneously, using identical nozzle sizes and uniform sprinklerpackages, etc.Lobuvu Farmers Association Report - 2009 Page - 32 -

Quality of infield installationThe lateral spacing was measured to range between 91 – 95m and emitter spacing rangedform 17 – 23m. With this installation the distribution pattern and the coefficient of uniformity ofthe sprinklers is distorted. There is a section where hydromatics are connected directly to themainline, that is, the mainline is also used as a lateral. This is not good irrigation practicebecause hydromatics are characterised by frequent breakages consequently the entiresystem must be shut down. In fact this is the very reason why the irrigation system has beenshut for almost two week. The mainline broke along one of these hydromatics.Figure 20. Floppy sprinkler block hydrant valvesLobuvu Farmers Association Report - 2009 Page - 33 -

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 HE 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 the operation of some components of the irrigation system. Also,this document helps in the formulation of a maintenance plan and provides guidelines to befollowed during maintenance.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:‣ 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. AlternativelyLobuvu Farmers Association Report - 2009 Page - 34 -

other 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.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. 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 mindLobuvu Farmers Association Report - 2009 Page - 35 -

here 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 Lobovu Farmers Association used to use the giveand take method. This method utilizes long term evaporation means and rainfall is accountedthrough rain gauge readings. The rain gauge was stolen and never replaced. A 12 hour standtime starting at 6am to 6pm is adopted giving 6.2 mm/day net application. This is below thesugar industry irrigation requirement of 6.5 mm/day. There is no scheduling tool to accuratelydetermine the amount of water applied and/or required with every irrigation.Given:12 hours every 7 daysThus: 12 Standing time (hours)7 Cycle length (days)Already calculated: Xg = 4.53 mmThus: hours x Xg every 7 daysThus: 54.3 mm 7 daysNet mm per day = 7.8 mm/dayThus Gross mm per day = 5.85 mm/dayTraining of farm manager and his assistantsSWADE, Swaziland Sugar Association and Ubombo Sugar endeavour to provide technicalassistance to this FA but based on the current condition of the irrigation system, more is stillto be done. More focus has to be put into training this FA on operation and maintenance ofthe irrigation system and ensure that equipment are replaced with correct ones and byqualified technicians. This capacity building exercise will go a long way into improvingefficiency in this irrigation project.6 . 3 M a i n t e n a n c e S u r v e yWhen the impact of maintenance practices was evaluated, it was decided to classify theexisting maintenance practices followed by the producer, according to existing literaturesources as acceptable if it will not influence the performance of the system adversely andLobuvu Farmers Association Report - 2009 Page - 36 -

unacceptable/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 5. 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 6. 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 UnacceptableLobuvu Farmers Association Report - 2009 Page - 37 -

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:The following constraints were identified to have an effect on productivity once the system isoperated.River pump station:‣ The river pump station was designed for two pumps and currently one pump in installed.During the evaluation this pump was not in operation.‣ One Hidrostal submersible axial flow pump is installed in this river pump station anddelivers water into a concrete reservoir adjacent the booster pumps station. There is nodesign information for this irrigation system and details of the motor could not begathered.‣ An intake sump was constructed for the Hidrostal Axial flow submersible pump on thebanks of the Usuthu River. This intake sump is supplied by a diversion canal from thereceding Usuthu River. This canal is currently out of structure and ineffective in catchingthe fluctuating Usuthu River hence brings more problems than solutions to the operationof the system.‣ Incorrectly sized fittings in suction and delivery manifolds affect system performance byincreases turbulence occurrences and cause irregular feeding of the pump hencecavitation. With such an installation wearing and maintenance cost of the pump willincrease.‣ The required power at design duty point of the river pump is approximately 23.9kW.According the ARC (2007), the power output of the motor must be 10-15% greater thanthe power required on the pump shaft giving a value of 30kW for the axial flow river pump.‣ 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.Lobuvu Farmers Association Report - 2009 Page - 38 -

Booster pump stations‣ Water is pumped from the river pumps into a concrete reservoir adjacent to is anotherpump station housing two KSB WKLn 150/4 pumps. These pumps are installed in such away that the impellor eye is below the minimal water level in the reservoir, which ensuresthat there is always water in the pump casing and suction pipe.‣ The reservoir water level should not be allowed to decrease below 1 meter. Below thislevel vortex will form thus reducing pump performance.‣ Both the river and booster pumps were not in operation during the evaluation. themainline had a leak and was under repair. The system has been off for more than twoweeks. Apart from this anomaly there is no flow meter and pressure gauges to monitorpump performance.‣ Just like in the case of river pumps system capacity was calculated for the total irrigatedarea to be 380m³/hr. For the pumps to meet the recommended sprinkler operatingpressure they must generate at least 142m.‣ At this duty point the installed WKLn 150/4 pumps must be powered by 220kW motors.This type of installation would mean the second pump is for backup purposes. Otherwise,considering both pumps pump duty reduces to 190m³/hr and 132kW size motor. Theformer is however outside the recommended operating pressure of the WKLn 150/4. Atthis duty point this pump operates at low efficiencies, hence the WKLn 125/5 isrecommended.‣ There is no mechanism to control the flow between the river pump and the concretereservoir.‣ The absence of functioning pressure and flow measuring devices in this pump’s deliverymanifold makes it impossible to measure and/or monitor pump performance.‣ 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.‣ Pump and motor protective mechanisms need to be improved‣ MCC panels have malfunctioning meters and there is no electric cable racking.MAIN LINE‣ Site investigation revealed that the 250mm bulk water mainline is under-designed.Lobuvu Farmers Association Report - 2009 Page - 39 -

‣ The delivery pipelines from the two pumps are interconnected hence during breakagesand/or maintenance one pump can be used in place of the other. The outlets of each ofthese pumps are connected to a 300mm main delivery manifold adapted to 315mm PVC.This mainline is correctly designed; however, pipe sizes, classes and orientation details ofthis irrigation system could not be obtained.‣ An undisputed conclusion on whether the irrigation mainline was correctly designed or notcan not be drawn until details on pipe size, pipe classes, and exact distances covered bythe different sizes are obtained.‣ Some sections of the mainline are leaking – overall system efficiency compromised.SPRINKLER INFIELD IRRIGATION‣ A complete system evaluation could not be conducted because the irrigation system wasshut down. The mainline had a leak and was being attended; this problem has draggedfor over two weeks.‣ Laterals of this dragline irrigation system are connected to the mainline through amechanical valve. There are no hydraulic valves yet for better performance these must beinstalled instead and equipped with pressure-regulating pilots.‣ The dragline irrigation development has a design lateral spacing of 90m and 36mdraglines. Some of the semi permanent laterals which ware suppose to be 18m apart hada big variation up to 24m which will influence the distribution uniformity. Sitemeasurements revealed a lateral spacing of at most 94m for the dragline irrigationsystem. Hydromatics are installed even on mainlines.‣ Sprinkler was not equipped with pressure regulators and was running on differentpressures and deliveries.‣ Sprinklers do not have the same sprinkler packages and different nozzle sizes wereidentified. This affects distribution uniformity, coefficient of uniformity and wetted area ofthe sprinkler hence reduces irrigation system efficiency.‣ There are a lot of leaks in the system and this drastically reduces pressure. These leaksare observed mainly in the sprinklers, sprinkler stands and dragline connections, andbroken draglines.‣ The irrigation system was installed over 12 years ago, and as years elapsed, the systemefficiency reduces due to equipment wearing out. As a matter of urgency some equipmentmust be replaced and the rest maintained for optimal performance.‣ Sprinkler nozzle wear is on average 3.7% increasing to 4.4% in some blocks.‣ The infield could not be evaluated because its pump was not running.Lobuvu Farmers Association Report - 2009 Page - 40 -

OVERALL MANAGEMENT AND MAINTENANCEManagement and maintenance‣ Old equipment reduces efficiency of system. This equipment includes hydromatics,draglines, sprinkler stands, sprinkler and nozzles. The most economic decision would beto replace this equipment instead of maintaining them.‣ Most equipment has been stolen and/or vandalised. This includes hydraulic valves,hydromatics, draglines, sprinkler stands, sprinkler and nozzles. These need to bereplaced or maintained.‣ 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.‣ 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.Operations‣ The late conclusion of loan agreements (seasonal loans) results in the late delivery ofinputs and late application of fertilizers and chemicals, which reduces yields and sucrosecontent, resulting in reduced financial returns per hectare and inability to recoup investedcapital‣ It can be argued that even relatively large reductions in interest rates have not had anysignificant impact on the sustainability of this sector. The sector appears to havedeteriorated to one of a sustained financial crisis.‣ Electricity bill for Lobovu Farmers association pumps 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 directionLobuvu Farmers Association Report - 2009 Page - 41 -

8 R E C O M M E N D A T I O N STo evaluate the constraints of the project properly we have decided to categorised therecommendations in four categories namelyA. Immediately: This has to been done direct after harvesting.B. Short term: This has to been done this seasonC. Medium term: This has to been done before replantD. Long term: This has to be rectified with replant.PUMP STATIONS:Immediately:‣ Rehabilitate current pump stations whilst waiting for the construction of the new pumpstation E 50 000.00Medium term:‣ Design supply and commission new pump station next to newly constructed balancingdam E 100 000.00‣ Design and install new pumping units (pump, motor and MCC) to be used at this newpump position E 150 000.00‣ Install flow and pressure measuring devices at new position E 70 000.00‣ Establish arrangement with a reputable establishment to assist with the maintenance ofall equipment.MAIN LINEImmediately:‣ Attend to leaks on mainlines and air-valves E 10 000.00‣ Do routine maintenance on all equipment. E 2 500.00Medium term:‣ Design, install and commission mainline with respect to new pumping position (adjacentthe balancing dam) E 137 500.00‣ Update all as-built drawings and make necessary adjustments on all pipes that do notconform to norms E 20 000.00Lobuvu Farmers Association Report - 2009 Page - 42 -

Long term:‣ Mainline section used as lateral must be relayed and a separate lateral installedE 70 000.00SPRINKLER 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 15 000.00Medium term:‣ Install hydraulic valves in every lateral E 20 000.00‣ Correct all hydraulic design faults in infields E 50 000.00Long term:‣ Replant all blocks containing old sugarcane and low yielding varieties‣ Expand development to unplanted areas on the periphery of the planted sugarcane‣ Install sub-surface and/or surface drainsOVERALL 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.‣ 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 costsLobuvu Farmers Association Report - 2009 Page - 43 -

Management‣ Compilation of an operation and maintenance manual to assist in the implementation of aproper maintenance and operation strategies for the association.‣ A proper scheduling tool must be adopted and, where possible, blocks scheduledaccording to soil type.‣ Establish arrangement with a reliable establishment to assist with the maintenance of allequipment.‣ Replace all old equipment‣ Strengthen training of FA on operation and maintenance and monitoring and evaluation ofirrigation system‣ Implement an irrigation pattern that will result into a 6.5 mm/ day in all blocks.Lobuvu Farmers Association Report - 2009 Page - 44 -

9 C O N C L U S I O NThis 88.1 hectare dragline irrigation development was designed and installed by D and Jinvestment, a Swazi owned company directed by Mr. Peter Dlamini. the bulk water supplynetworks was however designed and installed by the government of Swaziland. This includethe river pump, booster pump and bulk water mainline. The initial design was for 96 hectaresand after the construction of the LUSIP Canal across this farm, the productive area droppedto 88.1 ha. This irrigation scheme was implemented in 1997.River Pump StationThe river pump station was designed for two pumps and currently one pump is installed. theHidrostal submersible axial flow pump installed in this river pump station delivers water into aconcrete reservoir adjacent the booster pumps station. There is no design information for thisirrigation system and details of the motor could not be gathered. The required power atdesign duty point of the river pump is approximately 23.9kW. According the ARC (2007), thepower output of the motor must be 10-15% greater than the power required on the pumpshaft giving a value of 30kW for the river pump.An intake sump was constructed for the Hidrostal submersible pump on the banks of theUsuthu River. This intake sump is supplied by a diversion canal from the receding UsuthuRiver. This canal is currently out of structure and ineffective in catching the fluctuating UsuthuRiver hence brings more problems than solutions to the operation of the system. The waterdepth above suction inlets is below the recommended minimum, and is expected to furtherdecrease during the dry season. Under this condition air is sucked in with irrigation water andcavitates the pump. The effects of the shallow depth on the pumps are reflected throughvortex and pump cavitation. This significantly reduced pump efficiency and performance.Booster Pump StationWater is pumped from the river pumps into a concrete reservoir adjacent to is another pumpstation housing two KSB WKLn 150/4 pumps. These pumps are installed in such a way thatthe impellor eye is below the minimal water level in the reservoir, which ensures that there isalways water in the pump casing and suction pipe. Both the river and booster pumps werenot in operation during the evaluation. The mainline had a leak and was under repair. Thesystem has been off for more than two weeks. Apart from this anomaly there is no flow meterand pressure gauges to monitor pump performance.Lobuvu Farmers Association Report - 2009 Page - 45 -

Just like in the case of river pumps, system capacity was calculated for the total irrigated areato be 380m³/hr. For the pumps to meet the recommended sprinkler operating pressure theymust generate at least 142m. At this duty point the installed WKLn 150/4 pumps must bepowered by 220kW motors. This type of installation would mean the second pump is forbackup purposes. Otherwise, considering both pumps pump duty reduces to 190m³/hr and132kW size motor. The former is however outside the recommended operating pressure ofthe WKLn 150/4. At this duty point this pump operates at low efficiencies, hence the WKLn125/5 is recommended.Main Distribution LineAn undisputed conclusion on whether the irrigation mainline was correctly designed or notcan not be drawn until details on pipe size, pipe classes, and exact distances covered by thedifferent sizes are obtained.Infield Sprinkler IrrigationA complete system evaluation could not be conducted because the irrigation system was shutdown. The mainline had a leak and was being attended; this problem has dragged for overtwo weeks. It is strongly recommended to conduct the distribution and delivery tests afterharvesting to determine defects, if any, in the design and installation of the infields.Laterals of this dragline irrigation system are connected to the mainline through a mechanicalvalve. There are no hydraulic valves yet for better performance these must be installedinstead and equipped with pressure-regulating pilots.Two sprinkler packages with three different nozzle sizes were identified. Flow variation due tothe different sprinkler – nozzle combinations is 19.77% and is higher than the ARCrecommendation stating that the difference in discharge in a specific irrigation block may notvary by more than 10% from the average discharge. The different sprinkler packages have aneffect mainly on the wetting diameter due to the different body trajectory angle and nozzlesize has an effect flow.Sugarcane requires at least 6.5mm/day and the implemented irrigation pattern combined withhigh emitter discharge variation results to only 5.85mm applied and available to sugarcaneper day. Lobovu FA is, therefore, by far under-irrigating.Lobuvu Farmers Association Report - 2009 Page - 46 -

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, Malkerns canaloccasionally closes without notifying the farmers in advance, old and worn-out equipment,and frequent breakages of pumps, laterals and draglines.Lobuvu Farmers Association Report - 2009 Page - 47 -

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.Lobuvu Farmers Association Report - 2009 Page - 48 -

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. Zoldoske, D.F. and Solomon, K.H. 1988. Coefficient of Uniformity- What it tells us.Center for irrigation Technology, California State University, Fresno, California.Lobuvu Farmers Association Report - 2009 Page - 49 -

11 P R O D U C T I N F O R M A T I O NRiver pumps technical details;No pump specifications could be made as there were no detail available of the motor sizes.Sprinkler equipment specifications from the manufactureSoils classification according to SSALobuvu Farmers Association Report - 2009 Page - 50 -







Soils classification according to SSLobuvu Farmers Association Report - 2009 Page - 57 -



12 A P P E N D I C E SAttached are the following documentsAppendix 1: capital recovery factors (CRF)Lobuvu Farmers Association Report - 2009 Page - 60 -

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 0.160Lobuvu Farmers Association Report - 2009 Page - 61 -

Service Contract No 2007 / 147-446 - Swaziland

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?