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Toro Aqua-Traxx with the PBX Advantage Design Guide

1. IUO Ag Irrigation Aqua TraXX Design Manual By Michael J Boswell This publication is designed to provide accurate and informative opinion in regard to the subject matter covered It is distributed with the understanding that the authors publishers and distributors are not engaged in rendering engineering hydraulic agronomic or other professional advice Printing History First Edition June 1997 Second Edition August 1998 Third Edition October 1999 Fourth Edition August 2000 Toro Ag Irrigation 2000 TABLE OF CONTENTS CHAPTER I Aqua TraXX TAPE Principles of Operation Features and Advantages Specifications Use and Selection CHAPTER II SOIL Soil CHAPTER II WATER QUALITY AND TREATMENT Water Quality Water Treatment Chlorination Injection of Acid CHAPTER IV DESIGN CRITERIA Emission Uniformity EU Design Capacity CHAPTER V Aqua TraXX DESIGN Selecting Aqua TraXX Products Computer Program AquaFlow Submain Design Mainline Design CHAPTER VI INSTALLATION PROCEDURES Installation Connections Injection Equipment CHAPTER VII OPERATION AND MAINTENANCE Computing Irrigation Time Monitoring System Performance Maintenance Procedures for Aqua TraXX Tape APPENDIX A CONVERSION FACTORS APPENDIX B REFERENCE TABLES OF SELECTED DATA LIST OF FIGURES Figure 1 Aqua TraXX Tape Figure 2 Aqua TraXX on Lettuce Murcia Spain Figure 3 Turbulent Flowpath Design Details Figure 4 Aqua
2. 3 Install vacuum breakers on submain risers to prevent suction in lateral lines 4 Take care during installation to minimize contamination by soil insects pipe dope PVC pipe shavings and the like 5 Thoroughly flush the system before connecting tape to submains 6 Practice regular chemical treatment acid or chlorine 7 Flush tape lines on a regular basis Prevention of Insect Damage Ants wireworms and other insects may cause damage to tape Insect damage typically takes the form of holes chewed through the sides of tape Researchers have noted that insect damage is most severe in tape having wall thicknesses of less than 10 mils 0 010 inches Insect damage has been successfully controlled with insecticides However these chemicals are highly toxic and persist in the environment For this reason growers are advised to select a tape with sufficient wall thickness to prevent insects from making holes through the wall of the tubing Prevention of Root Intrusion In micro irrigation systems utilizing buried tape plant roots may grow into tape outlets effectively clogging them This so called root intrusion into tape outlets may be widespread throughout the field severely compromising the effectiveness of the irrigation system In advanced cases there is no alternative but to replace the tape The tendency for root intrusion to occur varies widely according to crop type the type of system components selected depth an
3. 5 8 Used for average run lengths 0 to 1 000 ft 7 8 Used for long run lengths up to 2 500 ft 1 3 8 Used for very long run lengths up to 5 000 ft 1 4 Chapter I Aqua TraXX Tape CHAPTER II SOIL SOIL Soil Water Relationships A micro irrigation system is a transportation system that delivers water to a point in or near the root zone The final link in this transportation system is the soil an essential bridge between the irrigation system and the plant The soil s physical and chemical properties determine its ability to transport and store water and nutrients The characteristics of soils vary widely according to their physical properties often determining the type of crop that can be grown and the type of irrigation system that is appropriate Therefore a thorough understanding of soil properties and soil water relationships is important for purposes of irrigation design Figure 4 Aqua TraXX on Tomatoes Florida sandy soil EGG CENA INNAM MN GG CN NCC A QN A i Chapter II Soil and Water Quality 2 1 Infiltration Rate The infiltration rate is the rate at which water enters the soil A soil s infiltration rate will vary greatly according to its chemistry structure tilth density porosity and moisture content The infiltration rate of a soil may impose a limitation upon the design of
4. amount of acid to inject into the system assuming the system flow rate is known CAUTION 1l Never add water to acid Always add acid to water 2 Never mix acid directly with chlorine or chlorine compounds This will release toxic chlorine gas 3 Inject acid downstream of filters and other metal components uu E T J M T S H ase Chapter III Water Treatment 3 15 CHAPTER IV DESIGN CRITERIA EMISSION UNIFORMITY EU The goal of irrigation design is the efficient distribution of water and nutrients to the crop One important measure of efficient distribution is the uniformity of water application Emission Uniformity is a measure of the uniformity of water application and is used in both the design and operation of a micro irrigation system Emission uniformity may apply to a single lateral line a submain block or an entire irrigation system Emission uniformity EU is defined ASAE EP405 as EU 1 127Cv Jn Qm Qa Eq 3 Where EU Emission Uniformity expressed as a decimal n For a point source emitter on a permanent crop the number of emitters per plant For a line source emitter on an annual crop either the spacing between plants divided by the same unit length of lateral line used to calculate Cv or 1 whichever is greater Cv The manufacturer s coefficient of variation for point or line source emitters expressed as a decimal Qm The minimum emitter fl
5. an irrigation system since water application rates in excess of the infiltration rate may result in runoff and erosion Soil Water Movement When water is applied slowly to the soil at a single point it is acted upon by the forces of gravity downward and capillary action radially outward producing a wetted pattern characteristic of the soil type and application rate Sandy soils are characterized by large voids between soil particles These large voids exert relatively weak capillary forces but offer little resistance to gravitational flow with the result that lateral and upward water movement is limited while downward water movement is rapid The wetting pattern for a sandy soil will therefore be deep with little lateral spread and upward water movement will be minimal To improve the lateral distribution of water on sandy soils some Florida tomato growers have installed two Aqua TraXX rows per bed as shown in Figure 4 At the other extreme a heavy clay soil exerts strong capillary forces but resists downward water movement by gravity The wetted pattern in a heavy clay soil will tend to be broad and of moderate depth because of the clay s high capillary forces and relatively low permeability In clay soils which have undergone compaction the downward movement of the water is even further restricted resulting in a wetted zone that is wide and shallow In clay soils the wetted pattern will depend not only on soil type but will also
6. annual crops the water requirement will increase with the growth of the plant and the plant leaf coverage For tree crops the system design capacity must be based upon the irrigation needs of the mature plant 4 2 Chapter IV Design Criteria 3 Rainfall patterns During periods of rainfall the crop s evapo transpiration rate will be low and the irrigation requirement will be reduced in proportion to the amount of effective rainfall the crop receives 4 Effective soil water storage The effective soil water storage is the volume of water stored in the soil which is available for use by the plant It is a function of the soil s ability to store a water reserve and the ability of the plant to draw upon that reserve Small shallow rooted drought sensitive plants in a sandy soil will require frequent irrigation whereas drought resistant plants with extensive root systems growing in a loamy soil will require less frequent irrigation 5 Where effective soil water storage is low the design capacity must be based upon the peak water requirement over a short period of time On the other hand where the effective soil water storage is relatively large it will serve as a water storage reservoir allowing the designer to base his design capacity upon average water requirements over a longer period of time 6 Croptype Crop type has a major influence in determining the design capacity of the system The water requirements of different crops v
7. diagnostic tools that will allow the operator to monitor the performance of the system and to detect possible problems in the early stages Included in this category are flow meters pressure gauges and submain riser filters Flow Meters System flow meters should be installed on the main supply lines and should provide readings of both instantaneous and cumulative flow These meters should be read regularly and the readings kept in a logbook Variations in the system flow rate may indicate that something in the system is amiss For example a gradual decline in system flow rate as measured by the flow meters may indicate a problem with the pumping station or a clogging problem in the field On the other hand an unexpected increase in the system flow rate might be an indication of a pipeline break or the presence of leakage in the system Measurements of cumulative flow will serve to verify water application schedules 7 2 Chapter VII Operation and Maintenance Pressure Test Points The system should have sufficient pressure testing points so that an overall check of the system pressures can be made Widely differing pressures in different sections of the system may indicate that some blockage leakage or other problem has arisen in some section of the system Pressure checks should be regularly made and the pressures recorded Submain Riser Filters Submain riser filters are small in line or wye strainers installed at each sub
8. for standard run lengths of up to 1 000 feet The 7 8 diameter is used on long run lengths of up to 2 500 feet and the 1 3 8 diameter is used on very long run lengths of up to 5 000 feet Figure 11 Aqua TraXX on Strawberries Dover Florida 2 Wall Thickness determines how rugged and durable the product will be For short term vegetable crops the experienced grower will generally be able to use the lightest weight tubing For longer term crops a heavier wall thickness will be more Chapter V Aqua TraXX Design 5 1 resistant to mechanical damage Aqua TraXX is manufactured in a range of wall thicknesses 4 mil 6 mil 8 mil 10 mil 12 mil and 15 mil one mil is 0 001 inch 3 Flow Rate selection will depend upon water quality the availability of water the desired length of the tape and the crop water requirement Aqua TraXX is available in four emitter flow rates These four flow rates are designated as Low Flow Medium Flow High Flow and Cane Flow It is advantageous to choose the lowest flow rate that will do the job because low flow rates minimize friction loss and allow for longer runs and better uniformity However low flow rates may require a higher level of filtration For the initial selection of a tape product it is often helpful to refer to the standard flow rate table The standard flow rate is the flow per 100 feet of tubing in gpm neglecting friction losses Table 4 provides standard flow rate data fo
9. hypochlorite decomposes readily at high concentrations and is affected by light and heat and must be stored in a cool location in corrosion resistant tanks CHLORINE GAS Chlorine gas is supplied as a liquefied gas under high pressure in containers varying in size from 100 Ib cylinders to one ton containers Chlorine gas is both very poisonous and very corrosive and because it is heavier than air adequate exhaust ventilation must be provided at the floor level of storage rooms INJECTION OF CHLORINE Chlorine may be introduced into the system in a number of ways Sodium hypochlorite liquid or calcium hypochlorite solid may be metered into the system Chapter III Water Treatment or chlorine gas may be dissolved directly into the supply line with the use of a metering device called a chlorinator Where chlorination of larger systems is required a gas system may be most economical but for smaller systems the solid or liquid forms may be more appropriate Gas chlorination while potentially hazardous under certain circumstances is widely used because it is generally the least expensive method The use of gas is also preferable in areas where the addition of sodium or calcium to the soil is to be avoided Chlorine is a strong oxidizing agent and in concentrated liquid or gaseous form can be hazardous if used without following the manufacturer s instructions Pressure relief valves should be installed on any tanks holding solutions of c
10. the microorganism killing efficiency of HOCI is about 40 to 80 times greater than that of OCI the effectiveness of chlorination is highly dependent upon the pH of the source water Thus water having a low pH will result in a high concentration of HOCI which is the more potent biocide Chlorine is highly reactive with many compounds Free available chlorine reacts strongly with readily oxidizable substances such as iron manganese and hydrogen sulfide often producing insoluble compounds which may precipitate out of solution These precipitates may cause clogging problems in a micro irrigation system Chlorine also reacts with ammonia producing compounds called chloramines and thus where nitrogen fertilizer is to be applied via the system steps should be taken to ensure that the nitrogen and chlorine are applied at different times The most common chlorine compounds used in micro irrigation systems are calcium hypochlorite sodium hypochlorite and chlorine gas CALCIUM HYPOCHLORITE Calcium hypochlorite is available commercially in a dry form as a powder or as granules tablets or pellets Calcium hypochlorite is readily soluble in water and under proper storage conditions is relatively stable Calcium hypochlorite should be stored in a cool dry location in corrosion resistant containers SODIUM HYPOCHLORITE Sodium hypochlorite familiar to most people as laundry bleach is available in solution in strengths up to 15 percent Sodium
11. vary markedly with the tilth of the soil For the majority of soils wetting patterns will be between the extremes exhibited by light sands and heavy clays In addition water movement in soils will be affected by the condition of the topsoil the permeability of the subsoil layers of soil with varying properties and the presence of a plow pan Figure 5 illustrates the relative shapes of wetting patterns that might be created under a tape outlet in various soil types 2 2 Chapter II Soil and Water Quality _Aqua Traxx Tape Clay Loam Sana Figure 5 Wetting Patterns For Clay Loam And Sand Application Rate In addition to soil type the application rate will affect the shape of the wetted pattern It is possible to alter the shape of the wetted zone by varying the application rate For example 10 gallons of water applied to a soil in 1 hour will probably produce a wider shallower wetted pattern than 10 gallons applied over a 10 hour period This is because a higher application rate tends to produce a wider zone of saturation under the emitter assisting horizontal movement For increased lateral movement light sandy soils require water application at higher rates Heavy clays and clay loams on the other hand often benefit from a lower water application rate This low rate avoids surface ponding and runoff and promotes deeper water penetration Table 1 provides data on the approximate size of the wetted area which can be expected un
12. water kilograms kilograms cu meter kilograms hectare kilograms sq cm kilograms sq cm kilograms sq cm kilograms sq cm kilograms sq cm kilograms sq cm kilograms sq meter kilograms sq meter kilograms sq meter kilograms sq meter kilograms sq meter kilograms sq meter kilometers kilometers kilometers kilometers kilometers hr kilometers hr kiloPascals kPa kilowatts kilowatts kilowatt hrs kilowatt hrs liters liters liters liters liters liters liters liters liters min liters min liters sec liters sec sq meter meters meters meters meters meters meters meters meters meters min meters sec TO CONVERT meters sec meters sec pounds sa in pounds pounds cu ft pounds acre dynes atmospheres feet of water in of mercury pounds sq ft pounds sq in atmospheres bars ft of water in of mercury pounds sq ft pounds sq in feet meters miles yards feet min feet sec pounds sq in BTU min horsepower BTU horsepower hrs cu cm cu feet cu inches cu meters cu yards gallons U S pints U S quarts U S cu ft sec gals sec gallons min gallons min sq ft centimeters feet inches kilometers miles naut miles stat millimeters yards miles hr feet min INTO feet sec kilometers hr 0 03613 2 205 0 06243 0 8924 980 665 0 9678 32 81 28 96 2 048 14 22 9 678x10 5 98 07x10 6 3 281x10 3 2 896x10 3 0 2048 1 422x10 3 3 281 1 000 0 6214 1 094 54 68 0 9113 0 14
13. 0 0 45 0 06 11 62 140 5 62 1 95 0 52 0 07 13 33 150 6 38 2 22 0 59 0 08 15 15 160 7 19 2 50 0 67 0 09 17 08 170 8 05 2 80 0 75 0 10 180 8 95 3 11 0 83 0 11 190 9 89 3 44 0 92 0 12 200 10 87 3 78 1 01 0 14 225 13 52 4 70 1 25 0 17 250 16 44 5 71 1 52 0 21 275 19 61 6 82 1 82 0 25 300 8 01 2 13 0 29 325 9 29 2 48 0 34 350 10 65 2 84 0 39 375 12 10 3 23 0 44 400 13 64 3 64 0 50 425 15 26 4 07 0 55 450 16 97 4 52 0 62 475 5 00 0 68 500 5 50 0 75 550 6 56 0 89 LOSSES IN PSI PER 100 FEET OF TUBE PSI 100 FT C 140 SIZE ID GPM SIZE ID GPM TABLE B 3 FRICTION LOSS TABLES FOR LAYFLAT HOSE 0 50 1 41 5 09 10 77 18 34 0 63 0 48 0 75 0 20 0 71 1 50 2 55 3 85 5 40 7 18 9 19 11 43 13 89 16 57 19 47 1 00 0 05 0 18 0 37 0 63 0 95 1 33 1 77 2 27 2 82 3 43 4 09 4 80 5 57 6 39 7 26 8 18 9 15 10 15 11 24 12 35 14 74 17 31 1 25 0 02 0 06 0 13 0 21 0 32 0 45 0 60 0 77 0 95 1 16 1 38 1 62 1 88 2 16 2 45 2 76 3 09 3 43 3 79 4 17 4 98 5 85 6 78 7 77 8 83 9 95 11 13 12 38 13 68 15 04 16 46 17 94 19 48 8 34 9 21 10 13 11 09 12 08 13 12 3 43 3 79 4 17 4 57 4 98 5 40 5 85 6 30 6 78 7 27 7 78 8 30 8 83 10 24 0 85 0 94 1 03 1 13 1 23 1 33 1 44 1 56 1 67 1 79 1 92 2 05 2 18 2 53 2 90 3 71 4 15 4 61 5 10 5 61 6 69
14. 2 ppm x 0 006 5 25 0 35 gallons per hour EXAMPLE 2 A grower wishes to use 10 0 NaOCl to achieve a 10 ppm chlorine level His system flow rate is 620 gpm At what rate should he inject the NaOCI SOLUTION IR 620 gpm x 10 ppm x 0 006 10 0 3 72 gallons per hour PE a UU E E ROO UE a o il 3 12 Chapter III Water Treatment SOLID FORM CALCIUM HYPOCHLORITE Ca OCl 2 Calcium hypochlorite is normally dissolved in water to form a solution which is then injected into the system Calcium hypochlorite is 65 chlorine hypochlorite by weight Therefore a 1 percent chlorine solution would require the addition of 8 34 0 65 12 8 pounds of calcium hypochlorite per hundred gallons of water Using this fact a stock solution of the desired strength may be mixed and used in the same manner as sodium hypochlorite solutions GASEOUS FORM Cl General Formula IR QxCx 0 012 Eq 2 Where IR Chlorine Injection Rate Ib day Q System Flow Rate gpm C Desired Chlorine Concentration ppm EXAMPLE A grower wants to inject gas chlorine into his system to achieve a 15 ppm chlorine concentration at the mainline injection point If the mainline flow rate is 2250 gpm what should the gas injection rate be SOLUTION IR 2 250 x 15 x 0 012 405 0 pounds per day Table 3 provides further guidelines for the computation of dosage levels for chlorination TABLE 3 CHLORINE EQUIVALENTS FOR COMMERCIAL SOURCES CHLORINE FORM 1 Ib EQU
15. 2 psi range Main Tube Flowpath Design amp Nomenclature LASER SLIT OUTLET WATER FLOW TURBULENT FLOW PATH 60 200 007 min x 010 max 008 min x 033 max 140 x 012 170 x 012 0 03 0 11859 0 50 0 09487 0 50 0 07115 0 50 0 04743 0 50 140 WATER INLET FILTERS Figure 3 Turbulent Flowpath Design Details Chapter I Aqua TraXX Tape 1 3 USE AND SELECTION Wall Thickness 4 mil Light walled products used for short season crops in soils with a minimum of rocks Recommended for experienced tape users 6 and 8 mil Intermediate products for general use in longer term crops and average soil conditions 10 15 mil Heavy wall designed to be used in rocky soils where insects and animals may cause damage or where the tape is to be used for more than one season Spacing 8 inch Used in closely spaced crops on sandy soils or where higher flow rates are desired 12 inch Used on crops in medium soils and average crop spacings 16 inch Used on wide spaced crops where a longer length of run is desired 24 inch Used for widely spaced crops heavy soils long run lengths Flow Rate Cane Flow Used for sugarcane High Flow Normally recommended for most crops and soils Medium Flow Recommended for longer runs on most crops and soils Low Flow Used in soils with low infiltration rates where long irrigation times are necessary or for very long runs Diameter
16. 3 0 14 0 14 0 15 0 15 Table 4 Standard Flow Rates For Aqua TraXX 5 2 Chapter V Aqua TraXX Design 4 Outlet Spacing selection is often based upon the initial germination or growth needs of the crop For seeds or seedlings that are planted in a closely spaced pattern it is advantageous to use a tape product with closely spaced outlets Soil type plays a major role in the determination of outlet spacing since the soil texture and condition determines water movement and the shape of the wetted profile COMPUTER PROGRAM AquaFlow AquaFlow provides designers with the information they need to design an Aqua TraXX tape system for optimum performance AquaFlow provides system operators with the information necessary to operate the system efficiently applying the desired amount of water and nutrients to the crop AquaFlow will help you to design a complete Aqua TraXX system including the selection of the Aqua TraXX tape and the sizing of submains and mainlines The AquaFlow program includes both metric and U S measurement units in the graphic screens for pressure profile and flow profile curves Metric units are given in kPa and meters U S units are given in psi and feet The following design example will familiarize the designer with the use of the AquaFlow program Design Example A designer is planning an Aqua TraXX tape system for tomatoes The plant rows run downhill at a 296 slope they are 400 feet long and they are spaced 36 inch
17. 503 56 92 1 341 3 413 1 341 1 000 0 03501 61 02 0 001 1 308x10 3 0 2642 2 113 1 057 5 886x10 4 4 403x10 3 15 852 1 4726 100 3 281 39 37 0 001 5 396x10 4 6 214x10 4 1 000 1 094 0 03728 196 8 MULTIPLY BY 3 281 3 6 meessc Komdesmn 008 tiles statute Komees tO missae meters T ters ters Om m mdes centimeters S o m msem 0 mi 33 0o mis Wde i pounds yes acai pounds rams as 00 pounds Meam S 0496 pounds Ame 0 08 pounds ofwater gallons OMS KPa 640 tonnes metic Kexms S tonnes metic pounds ES 000 tons shor wounds 299 A 4 Toro Micro Irrigation Design Manual REFERENCE TABLES OF SELECTED DATA TABLE B 1 ROUGHNESS COEFFICIENT C VALUES FOR HAZEN WILLIAMS EQUATION VALUES OF C TYPE OF PIPE RANGE NEW PIPE DESIGN C PVC 160 145 150 150 Polyethylene 150 130 140 140 Asbestos Cement 160 140 150 140 Cement Lined Steel 160 140 150 140 Welded Steel 150 80 140 100 Riveted Steel 140 90 110 100 Concrete 150 85 120 100 Cast Iron 150 80 130 100 Copper Brass 150 120 140 130 Wood Stave 145 110 120 110 Vitrified Clay 110 100 Corrugated Steel 60 60 Above values of C for use with Hazen Williams Equation friction head losses in feet per foot of pipe length for fresh water at 50 degrees Fahrenheit 10 472 Que Hf cH X pm xL Where Hf Friction Head Loss ft Roughness Coef
18. 7 DESIGN MENU GRAPH PRESSURE AquaFlow computes and plots the individual pressure profile curve representing the tape length selected The graph below shows the pressure profile for a 400 foot long run and provides design data including the inlet flow rate and the Emission Uniformity value for the single line M Graph Legend EU gt 90 EU 85 9 5 EU 85 5 8 Chapter V Aqua TraXX Design SUBMAIN DESIGN Submains provide water to individual field blocks distributing water at a uniform pressure to the Aqua TraXX lateral lines Submains may be constructed of PVC pipe PVC layflat hose or Oval Hose Oval Hose is a popular and widely used choice for submains because it is economical rugged and easy to handle and install Oval Hose can be retrieved from the field and used again year after year Oval Hose is manufactured in a round configuration and subsequently flattened and wound on reels or in coils for ease of handling and compact shipment After it is installed in the field and pressurized Oval Hose returns to its round configuration Aqua TraXX tape may be connected to Oval Hose submains using barbed connectors FCA0798 or leader tubing Good submain design incorporates a flushout valve at the end of the submain and a flushing manifold which is used to flush the entire block of lateral lines simultaneously Submain Riser Des
19. IVALENT Q PER ACRE FT Chlorine Gas 100 available Cl 1 0 Ib 2 7 Ib Calcium Hypochlorite 65 70 available Cl 1 5 Ib 4 0 Ib Sodium Hypochlorite Chapter III Water Treatment 3 13 15 available Cl 0 8 gal 2 2 gal 10 available Cl 1 2 gal 3 3 gal 5 available Cl 2 4 gal 6 5 gal This is the quantity required to treat one acre foot of water to attain 1 ppm chlorine at the injection point CAUTION L Never mix chlorine directly with any other chemicals 2 Store chlorine apart from other chemicals 3 Inject chlorine and acid into the system using separate injection points INJECTION OF ACID The injection of acid is generally done to lower the pH as a control mechanism for various water quality problems Acid treatment is often used to prevent precipitation of dissolved solids such as carbonates and iron Acid may also be used to discourage micro organic growth in the system and may be used in conjunction with chlorine to increase the concentration of HOCI which enhances chlorine s biocidal action The injection of acid is generally done on an intermittent basis and will not affect the growth of most perennial plants Caution should be exercised when handling acids because many system components and injection pumps are not resistant to acid Care should be taken that only pumps with acid resistant materials are used Among the various acids commonly used are Phosphoric acid which also adds phosphate to the root zone Hydro
20. TraXX on Tomatoes Florida sandy soil Figure 5 Wetting Patterns for Clay Loam and Sand Figure 6 Effect of Emitter Location on Salts Figure 7 Aqua TraXX on Head Lettuce Santa Maria CA Figure 8 Aqua TraXX on Broccoli Santa Maria CA Figure 9 Screen Mesh Sizes Compared to 0 020 Orifice Figure 10 Aqua TraXX on Celery Santa Maria CA Figure11 Aqua TraXX on Strawberries Dover Florida Figure 12 Example Submain Block Figure 13 Aqua TraXX Connection to Oval Hose Figure 14 Methods of Aqua TraXX Tape Connections Figure 15 Injecting Aqua TraXX Casa Grande Arizona Figure 16 Aqua TraXX Injection Tool Figure 17 Aqua TraXX on Peppers Florida sandy soil LIST OF TABLES Table 1 Approximate Size of Wetted Area Table 2 Water Quality Interpretation Chart Table 3 Chlorine Equivalents for Commercial Sources Table 4 Standard Flow Rates for Aqua TraXX Table 5 Friction Losses in PSI through Tape Connections LIST OF EQUATIONS Ej Ej E B bd E bd 22222252 NAM bh WN Chlorine Injection Rate Liquid Form Chlorine Injection Rate Gas Form Emission Uniformity EU Peak Evapotranspiration PET Friction Loss in Pipe Equation Velocity in Pipe Equation Irrigation Time 1 1 1 2 1 3 2 1 2 3 2 4 3 1 3 5 3 7 4 2 5 1 5 4 6 2 6 2 6 3 6 5 7 1 2 3 3 3 3 13 5 2 6 3 3 11 3 12 4 1 4 4 5 12 5 12 7 CHAPTERI Aqua TraXX TAPE PRINCIPLES OF OPERATION Aqua TraXX is a seamless extrude
21. a 4 3 Computing System Design Capacity Once the peak evapotranspiration requirement of the crop is known the system design capacity may be computed Assuming that PET is expressed in inches per day and that this water application is to be applied over the entire cultivated area the system design capacity may be computed by the formula PETxA 452 5 Eq 4 R T x EU 4 Where Q System Design Capacity gpm PET Peak Evapotranspiration inches per day A Area to be Irrigated acres T Irrigation Time hours per day EU Emission Uniformity decimal EXAMPLE A farmer wishes to irrigate an 80 acre field planted in Kiwi fruit He plans to irrigate a maximum of 12 hours per day and the PET for the mature crop will be 0 30 inches of water per day For an Emission Uniformity of 85 compute the system design capacity SOLUTION Q 4525x 039X90 _ 10647 gpm 12 x 0 85 4 4 Chapter IV Design Criteria CHAPTER V Aqua TraXX SYSTEM DESIGN SELECTING Aqua TraXX PRODUCTS Aqua TraXX is manufactured in a wide range of diameters wall thicknesses outlet spacings and flow rates to meet the specific requirements of various crops Designers should consider the following when selecting Aqua TraXX products 1 Diameter Aqua TraXX is available in three diameters 5 8 0 625 LD 7 8 0 875 LD and 1 3 8 1 375 LD and will fit standard fittings The standard 5 8 diameter is used in applications calling
22. allons min gallons min hectares hectares horsepower horsepower horsepower horsepower metric horsepower British horsepower horsepower horsepower inches inches inches inches inches inches in of mercury in of mercury in of mercury in of mercury in of mercury in of mercury in of water in of water in of water in of water TO CONVERT in of water atmospheres in of mercury at 0 C in of water at 4 C bars centimeters kilometers meters atmospheres in of mercury kg sq meter pounds sq in cucm cu feet cu inches cu meters cu yards liters gallons U S gallons Imp pounds of water cu ft sec liters sec cu ft hr acres sq feet Btu min foot Ibs min foot lbs sec horsepower British horsepower metric kg calories min kilowatts watts centimeters meters miles millimeters mils yards atmospheres feet of water kg sq cm kg sq meter pounds sq ft pounds sq in atmospheres inches of mercury kg sq cm ounces sq in INTO pounds sq ft 9 869x10 7 2 953x10 5 4 015x10 4 1 0x10 4 30 48 3 048x10 4 0 3048 0 02950 0 8826 304 8 0 4335 3 785 0 1337 231 3 785x10 3 4 951x10 3 3 785 1 20095 0 83267 8 3453 2 228x10 3 0 06308 8 0208 2471 1 076x10 5 42 44 33 000 550 0 9863 1 014 10 68 0 7457 745 7 2 54 2 54x10 2 1 578x10 5 25 4 1 000 2 778x10 2 0 03342 1 133 0 03453 345 3 70 73 0 4912 2 458x10 3 0 07355 2 540x10 3 0 5781 MULTIPLY BY 5 204 in of
23. ant in the flush water find out what it is Does it appear to be a bacterial slime Are large aggregated particles present Is there evidence of iron precipitation Is there any material which could be sand from the media filter Examine the contaminant under a microscope Put samples of the dirty water into two small jars or test tubes Treat one with a few drops of chlorine bleach and the ETAGE RUE UO eee eee Chapter VII Operation and Maintenance 7 3 other with a few drops of hydrochloric acid Note any changes chlorine will attack organic matter while acid will dissolve many inorganic precipitates Acid or chlorine will not affect soil and sand particles Prevention of Clogging The biggest potential problem facing the operator of a micro irrigation system is clogging Because the water passages in most tape emitters are very small they easily become clogged by particles of mineral or organic matter This can reduce emission rates cause non uniformity of water distribution and thereby cause stress and damage to the crop Growers sometimes inadvertently cause clogging by injecting inappropriate chemicals or other substances into their systems In some cases contaminants are present in irrigation water delivered to the user and are not adequately filtered out These contaminants may include soil particles living or dead organic materials and scale from rusty pipes In other cases contaminants enter the system during the installat
24. ary markedly because of several factors including the amount of leaf area on the plant and the type of leaf surface A wheat or sugar cane plant with vertically oriented leaves has a far greater leaf area per unit ground area than a sunflower plant with horizontally oriented leaves A plant with soft fleshy leaves such as tomato loses more water through evapotranspiration than a waxy leafed plant such as jojoba 7 Application efficiency Once the peak ET rate has been determined it can be expressed in terms of a required system flow rate The actual design capacity is then computed by dividing the required system flow rate by the application efficiency 8 Leaching requirement Where saline water sources are used particularly in arid regions lacking heavy seasonal rains or wherever salinity may become a problem it may be necessary to provide for leaching in the design of the irrigation system The amount of water that must be applied for leaching depends upon the soil characteristics and on the amount of salts present in the soil Generally about 80 percent of the soluble salts present in a soil profile will be removed by leaching with a depth of water equivalent to the soil depth to be leached Therefore if a soil rooting zone of two feet is to be leached of 80 percent of its soluble salts a water application of two feet must be applied Further water applications will produce little further leaching of salts Chapter IV Design Criteri
25. ater surface Chapter III Water Treatment 3 1 Where surface water sources are subject to seasonal variations in quality these sources should be sampled and analyzed when the water quality is at its worst Glass containers are preferable for sample collection and they should hold about a half gallon The containers should be thoroughly cleaned and rinsed before use to avoid contamination of the water sample Two samples should be collected The first sample should be used for all tests except iron and no additives are required The second sample is used for the iron analysis and after collecting the water ten drops of HCI should be added HCl is commonly available in the form of muriatic acid Sample bottles should be filled completely carefully labeled and tightly sealed Samples should be sent immediately to a water testing laboratory The following tests should be requested from the laboratory Salinity pH Calcium Magnesium Sodium Potassium Iron Manganese Boron Bicarbonate Carbonate Chloride Sulfate Sulfide the quantity and size of suspended solids and for city water supplies the free chlorine level The water should also be tested for the presence of oil especially in areas close to oil fields Oil will very rapidly block both sand media and screen filters Oil may also clog tape outlets and may attack plastic pipes tubing or other components Interpretation Of Water Quality Analysis Suspended Solids Suspended s
26. be installed above or below ground with a tractor mounted injector tool similar to the one shown in Figure 16 This type of injector may be fabricated on the Chapter VI Operation and Maintenance 6 3 farm or purchased from a number of manufacturers Typically from two to six reels of tape may be installed simultaneously with tractor mounted injectors of this type The design of tape injection equipment should take the following into account 1 Each tape reel should have a braking mechanism to maintain a slight tension and to prevent reel overrunning when the tractor slows or stops A simple and effective braking system can be made from an 11 inch wide strip of canvas draped over the tape reel and fastened at one end to the injector frame The other end of the canvas strip is folded over and sewn forming a pocket for weights 2 The reels must be monitored continuously during injection to insure a quality installation 3 Reels are heavy approximately 70 pounds and procedures for mounting them onto the tractor must take their weight into account 4 The tractor should carry spare reels that can be mounted when a reel runs out in mid field 5 Injection equipment used to install tape should be free of sharp edges burrs and areas where the tubing could be damaged Bends rollers and other points of contact with the tape should be kept to a minimum to reduce both the possibilities for damage and the tension on the tape as it i
27. ce water sources such as streams or reservoirs are used for irrigation The quality of effluent produced by a media filter depends upon the flow rate through the filter and on the type of sand used In general the lower the flow rate and the finer the sand the better the filtration will be SSS M SS SSS ee nl 3 8 Chapter III Water Treatment Media filters are cleaned by backwashing During this process the normal downward direction of water flow is reversed passing back upwards through the media fluidizing the media bed and removing trapped contaminants The velocity of the backwash is carefully regulated so that contaminants are removed and the sand media remains in the filter A media filter should be followed by a screen filter to protect against the possibility of the filter sand finding its way into the irrigation system CHLORINATION Prior to any discussion of adding chemicals to irrigation water it must be pointed out that there are two potential hazards involved 1 The first possible hazard associated with chemical injection is the direct use of irrigation water by people or animals Field workers accustomed to drinking or washing with irrigation water must be re educated and the designer should recognize that chemically treated water may be toxic 2 The second possible hazard is backflow Backflow is a reversal of direction of normal flow caused by siphonage or backpressure Backflo
28. chloric acid muriatic acid and Sulfuric acid sulfur dioxide All acids are hazardous if used incorrectly The procedure to use is as follows 1 Calculate the amount of acid to inject You will need to know the volume of water to be treated concentration and type of acid being used pH of water and desired pH after treatment 2 Injection should be started with the system operating 3 Proceed to an emitter on the nearest lateral and determine the pH using a pH test kit or pH indicator paper Allow sufficient time to obtain a steady reading 4 Adjust the injection rate 3 14 Chapter III Water Treatment 5 Repeat steps 3 and 4 until the desired concentration is obtained HOW TO CALCULATE AMOUNT OF ACID TO INJECT In order to calculate the amount of acid to add to irrigation water to achieve the desired pH a titration curve is necessary and this requires a laboratory with the proper equipment In the field it is easiest to take a 55 gallon drum and fill it with irrigation water Then slowly add the type of acid you wish to inject to the drum and stir the water to ensure complete mixing Measure the pH of the water and repeat until the desired pH is obtained The quantity of acid required may be quite small and using sulfuric acid as little as 0 7 fluid ounces may be required to reduce the pH from 7 to 4 When the quantity of acid required to correct the pH of the water has been measured it is a simple operation to calculate the
29. ckness does not affect hydraulic design the many wall thicknesses available are not listed individually TORO Ag aaa gar Chapter V Aqua TraXX Design 5 5 Aqua TraXX SELECTION MENU GRAPH PRESSURE When the GRAPH PRESSURE button is clicked AquaFlow computes and plots a family of pressure profile curves representing tape lengths out to an EU Emission Uniformity value of 80 The pressure profile curves are color coded to indicate the EU value ranges for each line length The graph below indicates that the selected Aqua TraXX product EA5xx0867 is suitable for run lengths as long as 550 feet at 10 psi inlet pressure and 2 slope Legend EU gt 90 EU gt 85 9 EU 85 5 6 Chapter V Aqua TraXX Design Aqua TraXX DESIGN MENU With the initial selection of EA5xx0867 made the next step is to go to the Design Menu AquaFlow preserves the previously entered inlet pressure land slope and Aqua TraXX part number for you You must now enter a specific tape LENGTH and SPACING this is the spacing in inches from tape to tape across the field and click the GRAPH PRESSURE button AquaFlow then computes and plots a pressure profile curve representing the selected tape length PEE CEECEE CEN p tT Enor m Main Menu 1 ENGTH FT ki 4 gu a i P Lera A z TIE Ej IESU ML L hr ES nm Chapter V Aqua TraXX Design 5
30. d drip tape with a molded turbulent flow emitter bonded to the inner wall Seamless construction eliminates seam failures and reduces the incidence of root intrusion Extrusion technology utilizes high quality extrusion grade engineering polymers renowned for their toughness and flexibility These polymers were developed specifically for use in harsh industrial and agricultural environments The exclusive flowpath molding process creates crisp well formed physical features resulting in excellent repeatability and high emission uniformity EU The turbulent flowpath design creates a clog resistant flow channel and permits longer run lengths and higher uniformity of water application As shown in Fig 1 water enters the flowpath through the filter inlets and then flows through the turbulent flow channel which accurately regulates the flow rate Finally the water flows through the laser made slit type outlets to the crop Laser Outlet Turbulent Flowpath if ads DSCC SO SO SOO BEEP ST S T ST ST SE SP SE SU S AAA N Outlet Chamber Figure 1 Aqua TraXX Tape Chapter I Aqua TraXX Tape 1 1 FEATURES AND ADVANTAGES Y JuUYU YU Y YU Y E d z i ara SE J Precision molded emitter for high uniformity Seamless construction for greater reliability Each flowpath has many filter inlets making it highly resistant to clogging Laser slit outlet eliminates startup clogging and impedes root intrusio
31. d of the water Settling basins are also used in conjunction with aeration to remove iron and other dissolved solids 3 6 Chapter III Water Treatment Centrifugal Sand Separators Centrifugal sand separators are used to remove sand scale and other particulates that are appreciably heavier than water Centrifugal sand separators will remove particles down to a size of 74 microns 200 mesh under normal operation Centrifugal sand separators are often installed on the suction side of pumping stations to reduce pump wear They are self cleaning and require a minimum of maintenance Centrifugal sand separators will not remove organic materials and they suffer from the drawback that the head loss across them is higher 8 to 12 psi than with other types of filters It is important that sand separators be sized correctly The operation of a separator depends upon centrifugal forces within a vortex created by the incoming flow thus separator size must be carefully matched to the design flow rate Pressure Screen Filters Pressure screen filters serve to remove inorganic contaminants such as silts sand and scale Pressure screen filters are available in a variety of types and flow rate capacities with screen sizes ranging from 20 mesh to 200 mesh In addition to primary filtration of water sources screen filters often act as backup filters to catch sand or scale which may have accidentally entered the system through pipeline breaks media filter fa
32. d placement of the drip tape and irrigation scheduling practices It is known that moisture stress encourages plant root structures to expand more aggressively seeking water It is also known that roots will find and follow a seam on buried drip tape and grow into outlets if they are placed along this seam Two of the most effective preventive measures against root intrusion are to schedule irrigation in such a way as to avoid moisture stress and to select tape types which do not have a seam Drip tapes employing slit type outlets are considerably less susceptible to root intrusion than are those with hole type outlets Other measures employed against root intrusion are chemical treatments with acid acidic fertilizers chlorine or chemicals which retard root growth It must be noted that this type of chemical treatment because it is used to retard the roots of the crop may lead to Chapter VII Operation and Maintenance 7 5 serious crop damage if done incorrectly Growers are strongly encouraged to seek expert advice before attempting chemical treatments to discourage root intrusion 7 6 Chapter VII Operation and Maintenance Chapter VII Operation and Maintenance 7 7 CONVERSION FACTORS TO CONVERT acres acres acres acres acres acre feet acre feet atmospheres atmospheres atmospheres atmospheres atmospheres bars bars bars bars bars BTU Centigrade centimeters centimeters centimeters cubic centimeters c
33. der average conditions Table 1 Approximate Size of Wetted Area SOIL TYPE WETTED RADIUS ft Coarse Sand 0 5 1 5 Fine Sand 1 0 3 0 Loam 3 0 4 5 Heavy Clay 4 0 6 0 Chapter II Soil and Water Quality 2 3 Tape Placement In Relation To The Plant Tape placement is an important factor in the performance of the irrigation system and the health of the crop The location of the tape in relation to the plant will affect germination and early growth establishment of the root system efficient utilization of water and nutrients and the effects of salinity on the plant Germination of seeds or initial growth of seedlings will usually require that the tape be placed in close proximity 18 inches or less in most soils to the plant In sandy soils this distance should be reduced to 12 inches or less The outlet spacing flow rate and location of the tape will establish the wetted zone and therefore the location of most intensive root development The root system can be encouraged to extend itself horizontally or vertically or it can be confined to a relatively small area The size and shape of the root system is important in terms of the stability and vigor of the plant and its ability to utilize the naturally occurring water and nutrients in the soil around it Because water and nutrients applied outside the confines of the root zone are wasted it is best to locate the tape near the center of the root zone Salts present in the soi
34. es apart There will be one Aqua TraXX line per plant row There will be four submains each 100 feet long The submains will each feed 34 tape lines and they will run downhill at a 1 slope The mainline runs parallel to the submains The designer has selected Aqua TraXX tape part number EA5060867 5 8 inch diameter 6 mil 8 inch spacing 0 67 gpm 100 feet He will run the system at an operating pressure of 10 psi He wants to achieve an overall EU of 90 within each submain block Figure 10 below illustrates the various elements of the submain block To begin the user clicks on the Red TORO icon on the computer desktop When the Main Menu is displayed the user clicks on the word Design on the upper menu bar Four sub menu selections appear We will use these sub menus in sequence to complete the design example Chapter V Aqua TraXX Design 5 3 Mainline Submain 400 Aqua TraXX Riser Tape Laterals 34 36 O C 100 Oval Hose Flushing Submain Manifold CN v Flushout Valve Figure 12 Example Submain Block 5 4 Chapter V Aqua TraXX Design Aqua TraXX SELECTION MENU From the AquaFlow Main Menu click on Design and then click on Aqua TraXX Selection Menu Choose an INLET PRESSURE of 10 PSI a LAND SLOPE of 2 and Aqua TraXX PART NUMBER EA5xx0867 Click the Graph Pressure button Note The xx in the part number designates the wall thickness in mils thousandths of an inch Since wall thi
35. ffective particularly if there is a heavy silt load in the water but they are considerably more expensive Copper sulfate should not be used in any system with aluminum pipe The recommended concentration of copper sulfate for algae control varies from a low of 0 05 to a high of 2 0 ppm depending upon the species of algae involved The dosage required can be based upon a treatment of the top 6 feet of water since algal growth tends to occur primarily where sunlight is most intense Green algae can only grow in the presence of light Algae will not grow in buried pipelines or in black polyethylene laterals or emitters However enough light may enter through exposed white PVC pipes or fittings to permit growth in some parts of the system These algae can cause clogging problems when washed into tape laterals Chlorination is the recommended treatment to kill algae growing within the irrigation system The chlorine concentration should be 10 to 20 ppm for between 30 and 60 minutes Where practical exposed PVC pipe and fittings should be painted with a PVC compatible paint to reduce the possibility of algal growth within the system Filtration Settling Basins Settling basins serve to remove the larger inorganic suspended solids from surface water supplies Often used for turbulent surface water sources such as streams or ditches settling basins frequently function as economical primary treatment facilities and can greatly reduce the sediment loa
36. ficient Flow Rate gpm Pipe Length ft Pipe Inner Diameter inches Jroa TABLE B 2 FRICTION LOSS IN POLYETHYLENE PE SDR RATED TUBE LOSSES IN PSI PER 100 FEET OF TUBE PSI 100 FT C 140 SIZE ID GPM 0 50 0 75 1 00 1 25 1 50 2 00 0 622 0 824 1 049 1 380 1 610 2 067 1 0 49 0 12 0 04 0 01 0 00 0 00 2 1 76 0 45 0 14 0 04 0 02 0 01 3 3 73 0 95 0 29 0 08 0 04 0 01 4 6 35 1 62 0 50 0 13 0 06 0 02 5 9 60 2 44 0 76 0 20 0 09 0 03 6 13 46 3 43 1 06 0 28 0 13 0 04 7 4 56 1 41 0 37 0 18 0 05 8 2 50 5 84 1 80 0 47 0 22 0 07 9 2 469 7 26 2 24 0 59 0 28 0 08 10 8 82 2 73 0 72 0 34 0 10 12 0 06 12 37 3 82 1 01 0 48 0 14 14 0 08 5 08 1 34 0 63 0 19 16 0 10 3 00 6 51 1 71 0 81 0 24 18 0 13 3 068 8 10 2 13 1 01 0 30 20 0 15 9 84 2 59 1 22 0 36 22 0 18 0 05 11 74 3 09 1 46 0 43 24 0 21 0 07 13 79 3 63 1 72 0 51 26 0 25 0 09 16 00 4 21 1 99 0 59 28 0 29 0 10 18 35 4 83 2 28 0 68 30 0 32 0 11 5 49 2 59 0 77 85 0 43 0 15 4 00 7 81 3 45 1 02 40 0 55 0 19 4 026 9 36 4 42 1 31 45 0 69 0 24 11 64 5 50 1 63 50 0 83 0 29 0 08 14 14 6 68 1 98 55 1 00 0 35 0 09 16 87 7 97 2 36 60 1 17 0 41 0 11 9 36 2 78 65 1 36 0 47 0 13 6 00 10 86 3 22 70 1 56 0 54 0 14 6 065 12 46 3 69 75 1 77 0 61 0 16 14 16 4 20 80 1 99 0 69 0 18 0 03 15 95 4 73 85 2 23 0 77 0 21 0 03 17 85 5 29 90 2 48 0 86 0 23 0 03 5 88 95 2 74 0 95 0 25 0 03 6 50 100 3 01 1 05 0 28 0 04 7 15 110 3 59 1 25 0 33 0 05 8 53 120 4 22 1 47 0 39 0 05 10 02 130 4 90 1 7
37. hlorine to guard against a buildup of pressure Chlorination of a system may be either continuous or intermittent depending upon the intended results Where the goal is to control biological growth in laterals or other parts of the system intermittent treatment has generally proved to be satisfactory Continuous treatment will be necessary in those instances where the goal is to treat the water itself as in the case where chlorine is injected to precipitate dissolved iron General recommendations for injection of chlorine follow 1 Inject chlorine at a point upstream of the filter This prevents growth of bacteria or algae in the filter which would reduce filtration efficiency It also permits the removal of any precipitates caused by the injection of chlorine and eliminates the filter as a potential incubator for organic growth 2 Calculate the amount of chlorine to inject The following information is necessary volume of water to be treated active ingredient of chlorine chemical being used and desired concentration in treated water 3 Injection should be started with the system operating 4 Sample the water output of an emitter on the nearest lateral and determine the level of free chlorine using a chlorine test kit Allow sufficient time to achieve a steady reading 5 Adjust the injection rate 6 Repeat steps 4 and 5 until the desired concentration is obtained 7 Sample the water output from an emitter at the end of the mos
38. ies down to a particle size of 70 microns 0 003 inch However high silt and clay loads greater than 200 ppm will quickly block a media filter resulting in inefficient operation and increased backwashing frequency Rather than using filtration alone to remove heavy silt and clay loads from the water it is often preferable to build a settling basin for preliminary treatment prior to Chapter III Water Treatment filtration The size of the settling basin will be determined by the system flow rate and the settling velocity of the particles to be removed This settling velocity in turn is determined by the particle size shape and density Figure 8 Aqua TraXX on Broccoli Santa Maria CA Very fine silts and colloidal clay particles are too small to be economically removed by means of a settling basin because they settle so slowly that a prohibitively large settling basin would be required Fortunately these clay particles are of a sufficiently small size to pass completely through the system without any adverse effects if the proper precautions are followed Silt and clay particles which pass through the settling basin and or the filter may settle out of the water in the tape lines where they may become cemented together by the action of bacteria to form large and potentially troublesome masses of slime In order to combat this tendency chlorination is often practiced to curb the growth of any biological organisms and submains and la
39. ign A submain riser serves to regulate water flow from the mainline to the submain A typical submain riser assembly will normally consist of A screen filter to prevent debris from entering the tape lines A manual or pressure regulating valve to control the flow rate A vacuum relief valve to prevent suction in the submain and tape lines A Schrader valve to be used as a pressure test point Ter E Chapter V Aqua TraXX Design 5 9 SUBMAIN DESIGN MENU With the Aqua TraXX selection and design completed the next step is to go to the Submain Design Menu As before AquaFlow preserves the previously entered design parameters for you You must now select a submain material Oval Hose or PVC select a pipe size enter a submain LENGTH SLOPE and PRESSURE and click the Plot Pressure button Hint To see the full list of available submain pipe selections click on the down arrow to the right of the Oval Hose label box Lintner m S a e eee eT 5 10 Chapter V Aqua TraXX Design SUBMAIN DESIGN MENU PLOT PRESSURE The Plot Pressure function plots pressure profiles of all the Aqua TraXX lines on the submain superimposed on one another These pressure profiles will vary vertically on the graph due to the pressure variation within the submain Note The submain pressure calculations begin at the downstream end of the submain and p
40. ilures or other unforeseen circumstances Figure 8 illustrates the relative sizes of screen mesh openings in comparison to an orifice having a diameter of 0 020 inches Pressure screen filters require regular cleaning of the screen element EE OO cR E Chapter III Water Treatment 3 7 0 020 Orifice 200 150 100 amp 0 80 Mesh 175 Microns OO7 150 Mesh 104 Microns 004 100 Mesh 147 Microns OO6 200 Mesh 74 Microns 0O3 Figure 9 Screen Mesh Sizes Compared To 0 020 Inch Orifice Gravity Screen Filters Gravity screen filters rely upon gravity instead of water pressure to move water through the screen Most gravity screens consist of 2 chambers separated by a fine mesh screen Pressure losses across gravity screens are in most cases negligible rarely exceeding one psi and for this reason gravity screens find applications in systems where pressure losses must be minimized Gravity screen filters are useful where an elevated water source is available Gravity screens are very effective on most surface water sources including canal and reservoir waters Media Filters Media filters are especially suitable for micro irrigation systems because they are a three dimensional filter trapping contaminants both at the surface and deeper down in the media bed Media filters serve to remove fine suspended solids such as algae soil particles and organic detritus They are frequently necessary where surfa
41. ion phase and are not adequately flushed out of the system Included in this category are insects Teflon tape PVC pipe shavings and soil particles Pipeline breaks often result in system contamination with soil causing subsequent clogging problems In buried systems soil particles may enter or be sucked into tape outlets Roots may grow into these buried outlets to plug them Finally contaminants may grow aggregate or precipitate in water as it stands in the lines or evaporates from tape outlets between irrigations lron oxide manganese dioxide calcium carbonate algae and bacterial slimes can form in micro irrigation systems under certain circumstances The solution to a particular clogging problem must be based upon the nature of the problem Acid treatment has been used successfully to dissolve calcium precipitates and chlorine is frequently used to decompose organic materials Once a system is badly clogged there is usually little that can be done to fix it Therefore the wisest course is to prevent clogging in the first place Experience has shown that most clogging problems can be avoided by following a few simple rules 1 Analyze the source water for suspended and dissolved solids and design the irrigation chemical injection and filter systems accordingly 2 Install secondary filters on submain risers to protect the system from pipeline breaks or filter system failures 7 4 Chapter VII Operation and Maintenance
42. is is done to minimize the damaging effects of waterhammer AquaFlow will help you to size the mainline once the maximum velocity hydraulic grade line and flow rates are specified AquaFlow utilizes the Hazen Williams equation to compute friction losses which is recalled here for PVC pipe C 150 as Hf 0 000977 Q 9 p 8 3 L Eq 5 Where Hf Friction Loss feet of water Q Hlow Rate gpm D Actual Pipe I D inches L Length of Pipe feet Velocity of flow in a pipeline may be computed as follows V 04085 Q D Eq 6 Where V Q D Velocity ft per second Flow Rate gpm Actual Pipe I D inches 5 12 Chapter V Aqua TraXX Design Chapter V Aqua TraXX Design 5 13 5 14 Mainline Design Menu The final step in the design process is to size the mainline For this example we will design a mainline which feeds four of the above submain blocks simultaneously Click on the Mainline Design Menu This menu will enable you to size the mainline one segment at a time To start enter the land elevations upstream and downstream enter the downstream flow rate feeding the last submain and the downstream pressure in this case we allow for a 5 psi pressure loss through the submain riser assembly Select a pipe type and click on a pipe size Values of head loss velocity and upstream pressure will appear in the appropriate boxes You may experiment with a number of different pipe sizes until you select the one you want
43. its ranges from dark brown if there is a mixture of iron to black if the manganese oxide is pure Caution should be exercised when chlorination is practiced with waters containing manganese due to the fact that there is a time delay between chlorination and the development of a precipitate Sulfides If the irrigation water contains more than 0 1 ppm of total sulfides sulfur bacteria may grow within the irrigation system forming masses of slime which may clog filters and tape outlets Interpreting The Water Analysis Table 2 provides a guideline for interpretation of water analysis results Table 2 Water Quality Interpretation Chart WATER QUALITY DEGREE OF PROBLEM PARAMETER NONE INCREASING SEVERE 1 Salinity EC mmho cm 0 0 0 8 0 8 3 0 3 0 TDS ppm 0 0 500 500 2 000 2 000 2 Permeability Caused by Low Salt EC mmho cm 0 5 0 5 0 2 0 2 0 0 TDS ppm 320 320 0 0 Caused by Sodium SARa 0 0 6 0 6 0 9 0 9 0 3 Toxicity Sodium SARag 0 0 3 0 3 0 9 0 9 0 Chloride me L 0 0 4 0 4 0 10 0 10 0 ppm 0 0 140 140 350 350 Boron ppm 0 0 0 5 0 5 2 0 2 0 4 Clogging Chapter III Water Treatment 3 3 Iron ppm 0 0 0 1 0 1 0 4 0 44 Manganese ppm 0 0 0 2 0 2 0 4 0 4 Sulfides ppm 0 0 0 1 0 1 0 2 0 2 Calcium Carbonate ppm No levels established WATER TREATMENT 3 4 Micro irrigation systems are characterized by large numbers of emitters having fairl
44. l or in the irrigation water will be concentrated at the perimeter of the wetted zone formed around the tape as shown in Figure 6 The placement of the tape will determine whether harmful salts are pushed out and away from the root zone or concentrated within it Figure 6 Effect Of Emitter Location On Salts 2 4 Chapter II Soil and Water Quality Determination of Wetting Pattern The wetting pattern for any given soil is difficult to predict accurately from knowledge of the soil type alone General principles may be outlined but for practical purposes a test of the wetting pattern should be carried out on the proposed site of the irrigation system Much can be learned about water movement by applying measured amounts of water to limited areas and observing the lateral and downward movement of water and the shape of the wetted zone at various time intervals Provided that the soils tested are representative the observations will have practical application to the design of the irrigation system Such experiments can reveal soil layers and compaction zones and can indicate water retention capacities and the time needed for the soil to reach field capacity at different depths in the soil A simple method for determining the wetting pattern in a particular soil consists of installing a tape lateral of the type to be used and connecting it to a temporary water source such as an elevated 55 gallon drum The drum is filled with water and the
45. main riser Under normal conditions these filters which are usually 80 120 mesh will collect few if any contaminants because the main filtration system will normally have removed this material Periodic examination of these riser filters can be a valuable indication that the system is contaminated In the case of a pipeline break or a failure of the main filter station riser filters will help to prevent foreign material from entering the tape lines MAINTENANCE PROCEDURES FOR Aqua TraXX TAPE Flushing In many micro irrigation systems it has been found that provisions must be made to flush submain lines and lateral lines to remove settled sediments and flushing constitutes an important maintenance routine Research has shown that most settled sediments can be flushed from pipe or tubing with a flow velocity of one foot per second which is referred to as the scour velocity In standard half inch lateral lines the 1 ft sec scour velocity is equivalent to a flow rate of 1 gpm at the downstream end Mainlines submains and lateral lines should be flushed thoroughly prior to system startup and tape lines should be regularly flushed during the season Open the ends of the lateral lines while the system is running and allow water to run into a container until it runs clear Collect some of the dirty water in a glass jar and examine it carefully Take note of the nature of the impurities in the water If there is a significant amount of contamin
46. n Truly turbulent flowpath provides excellent uniformity with reduced clogging Available in a wide range of wall thicknesses outlet spacings and flow rates Highly visible blue stripes for quality recognition and Emitter UP indicator Superior tensile and burst strength Tough abrasion resistant material reduces field damage East and West Coast manufacturing for prompt delivery and enhanced availability uM Figure 2 Aqua TraXX on Lettuce Murcia Spain 1 2 Chapter I Aqua TraXX Tape SPECIFICATIONS Aqua TraXX Diameter amp Wall Thickness Dimensions Diameter Wall mils 5 8 4 6 8 10 12 15 7 8 8 10 12 1 3 8 15 Min PSI Max PSI ReelLength Reel Weight 4 10 13 000 70 Ibs 4 12 10 000 66 lbs 4 15 7 500 63 Ibs 4 15 6 000 60 Ibs 4 15 5 100 58 lbs 4 15 4 000 61 lbs 4 15 6 000 68 Ibs 4 15 4 400 65 lbs 4 15 4 000 61 lbs 4 15 2 700 74 Ibs Flowpath Specifications amp Dimensions Number of Inlets Number of Inlets Inlet Dimensions Flowpath Dimensions Outlet Dimensions Outlet Dimensions Coefficient of Variation Flow Coefficient Cd amp X Flow Coefficient Cd amp X Flow Coefficient Cd amp X Flow Coefficient Cd amp X Hazen Williams C Factor 8 amp 16 spacing 12 amp 24 spacing All All 4 amp 6mil 8 15 mil All Cane Flow 6 12 psi range High Flow 6 12 psi range Med Flow 6 12 psi range Low Flow 6 1
47. n the underside of clear plastic will focus sunlight like a magnifying glass burning holes in the tape 6 Care should be taken during installation to prevent soil insects and other contaminants from getting into the tape Ends should be closed off by kinking or knotting until the tape can be hooked up to the system 7 Tape must be monitored as it is injected into the soil Someone should be watching to insure that the tape maintains its blue stripes upwards orientation to assist in case the tape becomes tangled in the injector and to signal the tractor driver when the tape reel is empty and must be replaced pm a SSS Chapter VI Operation and Maintenance 6 1 CONNECTIONS Aqua TraXX tape is connected to Oval Hose submains using either a plastic fitting or a length of leader tubing as shown in Fig 10 Fittings are popular because they are quickly and easily installed they provide a strong and rugged aC connection and they can be re used for many years Figure 13 Aqua TraXX Connection to Oval Hose AQUA TRAXX Tape FCAO798 amp Fitting Figure 14 Methods of Aqua TraXX Tape Connections 6 2 Chapter VI Operation and Maintenance TABLE 5 Friction Losses in PSI through Tape Connections Flow Rate GPM FCA0798 1 0 23 1 5 0 49 2 0 83 2 5 1 25 3 1 74 3 5 2 31 4 2 95 INJECTION EQUIPMENT Figure 15 Injecting Aqua TraXX Casa Grande Arizona Aqua TraXX tape may
48. note that the Velocity box turns yellow warning for velocities over 5 feet per second When you are satisfied click Next The program will store the design values for the first segment and advance to the next segment where all the steps above are repeated When the last segment has been completed click Done Chapter V Aqua TraXX Design Mainline Design Summary When you click the Done box the program displays the Mainline Design Data summary for you on the screen as shown below L1 Report Preview PVC PIPE MAHLIHE DESIGH DATA Pipe Pipe Pipe Head Flow Down Stream Up Stream Part Length Flow Diam Loss Speed Eley Press Elev Press Se Number Feet GPM ch PSI Ft Min Feet PSI Feet PSI 3 IN CL100 100 95 3 330 6 3 5 100 15 0 101 15 1 41N CL100 100 189 4290 6 4 2 101 15 1 102 15 3 5 IN CL100 100 284 5291 4 4 1 102 15 3 103 15 3 amp IN CL100 100 378 6 301 3 3 8 103 15 3 104 152 Chapter V Aqua TraXX Design 5 15 5 16 Chapter V Aqua TraXX Design Design Report AquaFlow will produce a design report that can be printed out for your customer and will store the report on your hard drive for future reference In order to produce the Design Report click Report on the main menu To generate the report first verify the data presented in the Report Menu Then select the graphs and tables you want to include Click the Verify Customer button to enter or verify customer information Click the Select L
49. ogos button to put the Toro Ag logo the Aqua TraXX logo and your company Logo on the front page of the report Click Print Preview and AquaFlow will preview the report for you on your screen Finally click Print and AquaFlow will print the report to your printer Chapter V Aqua TraXX Design 5 17 5 18 Chapter V Aqua TraXX Design CHAPTER VI INSTALLATION PROCEDURES INSTALLATION The following recommendations apply to the installation of Aqua TraXX tape 1 Store tape reels in a covered area protected from sunlight and rain 2 Install tape with the blue stripes and outlets facing upwards Fine soil particles in the incoming water will normally settle to the bottom of the tape Installation of tape upside down may result in clogging if there is any contamination in the incoming water 3 An air vacuum relief valve should always be installed at the submain riser to prevent suction from occurring in the tape when the system is shut down Suction in buried tape will tend to draw muddy water back into the tubing through the outlets causing contamination 4 Tape may be laid on the surface or buried Burial is preferred where possible since it protects the tubing from accidents and animal damage reduces clogging maintains tape location and alignment reduces surface evaporation and insures that water is applied at the desired location J Tape must be buried when used under clear plastic mulch Condensed water droplets o
50. olids in the water supply include soil particles ranging in size from coarse sands to fine clays living organisms including algae and bacteria and a wide variety of miscellaneous waterborne matter Suspended solids loads will often vary considerably over time and seasonally particularly when the water source is a river lake or reservoir Calcium Calcium Ca is found to some extent in all natural waters A soil saturated with calcium is friable and easily worked permits water to penetrate easily and does not puddle or run together when wet Calcium in the form of gypsum is often applied to soils to improve their physical properties Generally irrigation water high in dissolved calcium is desirable although under certain conditions calcium can precipitate out and cause clogging Iron Iron Fe may be present in soluble form and may create clogging problems at concentrations as low as 0 1 ppm Dissolved iron may precipitate out of the water due 3 2 Chapter III Water Treatment to changes in temperature in response to a rise in pH or through the action of bacteria The result is an ocher sludge or slime mass capable of clogging the entire irrigation system Manganese Manganese Mn occurs in groundwater less commonly than iron and generally in smaller amounts Like iron manganese in solution may precipitate out because of chemical or biological activity forming sediment which will clog tape emitters The color of the depos
51. ow rate for the minimum pressure Hm in the system in gph Qa The average or design emitter flow rate for the average or design pressure Ha in gph Equation 3 incorporates two distinct and independent factors into an expression of emission uniformity The first factor 1 1 27Cv 4n expresses the flow rate variation resulting from manufacturing variation Cv which is computed for a sample population of emission devices as the standard deviation divided by the mean For Aqua TraXX tape systems Cv 03 and n 1 this factor is equal to 0 96 The second factor Qm Qa expresses the flow rate variation caused by pressure variations within the field and is a function of irrigation design Therefore for a typical Aqua TraXX system EU is equal to 0 96 Qm Qa ee ee sss Chapter IV Design Criteria 4 1 Figure 10 Aqua TraXX on Celery Santa Maria CA DESIGN CAPACITY Design capacity is the maximum rate of irrigation water that the system can apply Design capacity is based upon the anticipated Peak Evapotranspiration PET of the crop This maximum water requirement will be a function of the following factors 1 Climate The peak water use period for the crop occurs during the hottest period of the growing season For a summer crop July and August are often the peak use months Other factors that will affect the peak use period are relative humidity day length wind patterns and the intensity of sunlight 2 Crop maturity On
52. r the various Aqua TraXX flow rates and outlet spacings AQUA TRAXX FLOW RATES Q100 GPM PER 100 FEET PART SPACING 4 5 6 7 8 9 10 11 12 13 14 15 NUMBER Inches PSI PSI PSI PSI PSI PSI PSI PSI PSI PSI PSI PSI CANE FLOW EAXxx0884 8 0 59 0 66 0 73 0 78 0 84 0 89 0 94 0 98 1 03 1 07 1 11 1 15 EAXxx1256 12 0 40 0 44 0 48 0 52 0 56 0 59 0 63 0 66 0 68 0 71 0 74 0 77 EAXxx1642 16 0 30 0 33 0 36 0 39 0 42 0 44 0 47 0 49 0 51 0 53 0 55 0 57 EAXxx2428 24 0 20 0 22 0 24 0 26 0 28 0 30 0 31 0 33 0 34 0 36 0 37 0 38 HIGH FLOW EAXxx04134 4 0 95 1 06 1 16 1 25 1 34 1 42 1 50 1 57 1 64 1 71 1 77 1 84 EAXxx0867 8 0 47 0 53 0 58 0 63 0 67 0 71 0 75 0 79 0 82 0 86 0 89 0 92 EAXxx1245 12 0 32 0 35 0 39 0 42 0 45 0 47 0 50 0 52 0 55 0 57 0 59 0 61 EAXxx1634 16 0 24 0 27 0 29 0 31 0 34 0 36 0 38 0 39 0 41 0 43 0 44 0 46 EAXxx2422 24 0 16 0 18 0 19 0 21 0 22 0 24 0 25 0 26 0 27 0 29 0 30 0 31 MED FLOW EAXxx0850 8 0 36 0 40 0 44 0 47 0 50 0 53 0 56 0 59 0 62 0 64 0 67 0 69 EAXxx1234 12 0 24 0 27 0 29 0 31 0 34 0 36 0 38 0 39 0 41 0 43 0 44 0 46 EAXxx1625 16 0 18 0 20 0 22 0 24 0 25 0 27 0 28 0 29 0 31 0 32 0 33 0 34 EAXxx2417 24 0 12 0 13 0 15 0 16 0 17 0 18 0 19 0 20 0 21 0 21 0 22 0 23 LOW FLOW EAXxx0834 8 0 24 0 27 0 29 0 31 0 34 0 36 0 38 0 39 0 41 0 43 0 44 0 46 EAXxx1222 12 0 16 0 18 0 19 0 21 0 22 0 24 0 25 0 26 0 27 0 29 0 30 0 31 EAXxx1617 16 0 12 0 13 0 15 0 16 0 17 0 18 0 19 0 20 0 21 0 21 0 22 0 23 EAXxx2411 24 0 08 0 09 0 10 0 10 0 11 0 12 0 13 0 1
53. roceed to the upstream end Therefore the last curve plotted is at the submain inlet Legend EU gt 90 EU gt 85 EU 85 Chapter V Aqua TraXX Design 5 11 MAINLINE DESIGN The initial stage of mainline design consists of determining its location Laying out the route for the mainline to follow is often a trial and error procedure involving analysis of the costs and benefits of a number of alternative routes Once the mainline route has been chosen the proper pipe sizes must be specified For small systems the mainline can often be designed without an elevation drawing However for large or complex systems it is best to prepare an elevation drawing of the topography that the mainline will traverse The required submain pressure in feet is superimposed on the drawing to indicate the minimum allowable pressure at any point Then the proposed hydraulic grade line may be drawn in from the inlet of the mainline to the end Once the proposed hydraulic grade line has been drawn and the required flow rates calculated individual sections of the mainline are sized each section being designed to most closely adhere to the specified hydraulic grade line The designer must also compute static pressures in the pipelines and check each section to ensure that the average water velocity does not exceed a specified limit usually 5 to 10 feet per second Th
54. s injected 6 4 Chapter VI Operation and Maintenance 20 00 m 1 50 m 11 50 m T EI i A 12 00 6 00 9 00 Y lo 6 00 ar a 1 00 d 14 50 y A ger Els N ZEN N V y j V p E Th H c 3 00 12 00 o us ITEM NO QTY Material 3 X 1 498 X 247 Channel 4 X 1 647 X 258 Channel A FIGURE 16 Aqua TraXX INJECTION TOOL Chapter VI Operation and Maintenance Tool Bar Clamp 1 X 3 Tool Steel 1 CF Steel 3 16 Aluminum Plate 1 1 4 Sweep Elbow 1 1 4 FPT Coupling YO lo INI D JB FW IN 1 1 4 MPT Hex Bushing e 1 4 Steel Plate j IN Ie e e Nle e ee DOO 1 4 Steel Plate 6 6 Chapter VI Operation and Maintenance CHAPTER VII OPERATION AND MAINTENANCE COMPUTING IRRIGATION TIME Once ET has been determined the irrigation time T may be computed In order to perform the calculation it is necessary to know the average Q100 flow rate gpm per 100 feet and the system Emission Uniformity EU For row crops on Aqua TraXX tape the irrigation time T may be computed from the following formula Sx ET T 1 04 x Eq 7 Q 100 x EU Where T Irrigation Time hours S Average Tube Spacing feet ET Evapotran
55. spiration inches Q 100 Average Q100 Flow Rate gpm per 100 feet EU System Emission Uniformity decimal _ SES Figure 17 Aqua TraXX on Peppers Florida sandy soil Chapter VII Operation and Maintenance 7 1 EXAMPLE In a field of Pima cotton growing in Arizona the previous day s ET value was found to be 0 221 inches The cotton rows are spaced 40 inches 3 33 feet apart with Aqua TraXX tape buried under each row The average flow rate is 0 30 gpm per 100 feet and the system emission uniformity is 90 percent Find T SOLUTION T 104x 3 33 x 0 221 2 8 hours 0 30 x 0 90 On newly planted acreage the computed ET and therefore the irrigation time T may be quite low Nevertheless because the young plants are not likely to have extensive root systems it is best to apply this small amount on a frequent basis rather than attempting to apply more water less frequently On established crops however it is usually best to have a minimum irrigation period of one hour or longer This minimizes uneven distribution due to mainline fill and drain times and establishes a larger wetting pattern under each tape outlet For example if the irrigation time is determined to be 35 minutes for a given day it would probably be better to accumulate the time for two days and irrigate 70 minutes every other day MONITORING SYSTEM PERFORMANCE The well designed micro irrigation system will have built in
56. t distant lateral and determine the free chlorine level If there is a marked decrease in the concentration increase the injection rate to compensate for the chlorine absorption in the system RECOMMENDED CHLORINE CONCENTRATION Chapter III Water Treatment 3 11 The following are guidelines for the concentrations which may be required These concentrations are sampled at the end of the furthest lateral 1 Continuous treatment to prevent growth of algae or bacteria to 2 ppm Pt Intermittent treatment to kill a buildup of algae or bacteria 10 to 20 ppm for 30 to 60 minutes In most cases where control of micro organic slimes or growths is desired intermittent treatment is recommended The frequency of intermittent treatment will depend upon the level of contamination in the water supply Begin treatments on a frequent basis and then gradually space the treatments farther apart if conditions permit it HOW TO CALCULATE THE AMOUNT OF CHLORINE TO INJECT LIQUID FORM SODIUM HYPOCHLORITE NaOCl General Formula IR QxCx0 006 8S Eq 1 Where IR Chlorine Injection Rate gallons hour Q System Flow Rate gpm C Desired Chlorine Concentration ppm S Strength of NaOCl Solution percent EXAMPLE 1 A grower wishes to use household bleach NaOCl 5 25 active chlorine to achieve a 2 ppm chlorine level at the injection point His system flow rate is 155 gpm At what rate should he inject the bleach SOLUTION x 155 gpm x
57. teral lines are regularly flushed to remove sediments Growth Of Bacterial Slime In The System Bacteria can grow within the system in the absence of light They may produce a mass of slime or they may cause iron or sulfur to precipitate out of the water The slime may clog emitters or it may act as an adhesive to bind fine silt or clay particles together to form aggregated particles large enough to cause clogging The usual Chapter III Water Treatment 3 5 treatment to control bacterial slime growth is chlorination on a continuous basis to achieve a residual concentration of 1 to 2 ppm or on an intermittent basis at a concentration of 10 to 20 ppm for between 30 and 60 minutes Growth Of Algae Within The Water Supply Or The System Algae may grow profusely in surface waters and may become very dense particularly if the water contains the plant nutrients nitrogen and phosphorus When conditions are right algae can rapidly reproduce and cover streams lakes and reservoirs in large floating colonies called blooms In many cases algae may cause difficulty with primary screening or filtration systems because of a tendency for algae to become entangled within the screen Algae can effectively be controlled in reservoirs by adding copper sulfate The copper sulfate may be placed in bags equipped with floats and anchored at various points in the reservoir or it can be broadcast over the water surface Chelated copper products may be more e
58. test system is allowed to run for some length of time Observations of the wetting pattern are made by measuring the wetted surface diameter and by digging beneath the surface to measure the extent of subsurface water movement This test will provide extremely valuable information concerning wetting patterns and water movement in the specific soil type of interest Chapter II Soil and Water Quality 2 5 CHAPTER III WATER QUALITY AND TREATMENT WATER QUALITY Taking A Water Sample For Analysis The preliminary study for a micro irrigation system will require a careful analysis of the source water A micro irrigation system requires good quality water free of all but the finest suspended solids and free of those dissolved solids such as iron which may precipitate out and cause problems in the system Neglecting to analyze the quality of source water and provide adequate treatment is one of the most common reasons for the failure of micro irrigation systems to function properly Figure 7 Aqua TraXX on Head Lettuce It is important that a representative water sample be taken If the source is a well the sample should be collected after the pump has run for half an hour or so For a tap on a domestic supply line the supply should be run for several minutes before taking the sample When collecting samples from a surface water source such as a ditch river or reservoir the samples should be taken near the center and below the w
59. ubic centimeters cubic centimeters cubic centimeters cubic centimeters cubic feet cubic feet cubic feet cubic feet cubic feet cubic feet cubic feet cubic feet cubic feet sec cubic feet sec cubic inches cubic inches cubic inches cubic meters cubic meters cubic meters TO CONVERT INTO hectares sq feet sq meters sq miles sq yards cu feet gallons ft of water in of mercury kg sq cm kg sq meter pounds sq in atmospheres dynes sq cm kg sq meter pounds sq ft pounds sq in kilowatt hrs Fahrenheit feet inches millimeters cu inches gallons U S liters pints U S quarts U S cu cm cu inches cu meters cu yards gallons U S liters pints U S quarts U S million gals day gallons min cu cm gallons liters cu yards gallons U S liters INTO MULTIPLY BY 0 4047 43 560 4 047 1 562x10 3 4 840 43 560 3 259x10 5 33 90 29 92 1 0333 10 332 14 70 0 9869 1 0x1046 1 020x10 4 2 089 14 50 2 928x10 4 C x 1 8 32 3 281x10 2 0 3937 10 0 06102 2 642x10 4 0 001 2 113x10 3 1 057x10 3 28 320 1 728 0 02832 0 03704 7 48052 28 32 59 84 29 92 0 646317 448 831 16 39 4 329x10 3 0 01639 1 308 264 2 1 000 MULTIPLY BY Dvnes sa cm Dynes sq cm Dynes sq cm Dynes sq cm feet feet feet feet of water feet of water feet of water feet of water gallons gallons gallons gallons gallons gallons gallons Imp gallons U S gallons of water gallons min g
60. w may result in contamination of potable water supplies such as reservoirs wells municipal pipe lines and so forth unless the designer has incorporated a suitable backflow prevention device into the system The practice of chlorination which is the addition of chlorine to a water source has been used for many decades as a means of purifying drinking water supplies Chlorine when dissolved in water acts as a powerful oxidizing agent and vigorously attacks microorganisms such as algae fungi and bacteria Chlorination is an effective economical solution to the problem of orifice and emitter clogging where such clogging is due to micro organic growths When chlorine is dissolved in water it combines with water in a reaction called hydrolysis The hydrolysis reaction produces hypochlorous acid HOCI as H O Cl HOCI H Clr Following this reaction hypochlorous acid then undergoes an ionization reaction as HOCI H OCI Hypochlorous acid HOCI and hypochlorite OCI which are together referred to as free available chlorine coexist in an equilibrium relationship that is influenced by temperature and pH Where water is acidic low pH the above equilibrium shifts to Chapter III Water Treatment 3 9 3 10 the left and results in a high percentage of the free available chlorine being in the form of HOCI Where the water is basic high pH a high percentage of the free available chlorine is in the form of hypochlorite Since
61. y small flow paths Because these small flow paths are easily clogged by foreign material many water sources require some treatment to ensure the successful long term operation of the system Nearly all water sources can be made suitable for micro irrigation by means of appropriate physical and or chemical treatment The various water quality problems encountered in operating micro irrigation systems are outlined below In some situations two or more of these problems may be present giving rise to more complex treatment procedures 1 Presence of large particulate matter in the water supply 2 Presence of high silt and clay loads in the water supply 3 Growth of bacterial slime in the system 4 Growth of algae within the water supply or the system 5 Precipitation of iron sulfur or calcium carbonates Presence Of Large Particulate Matter Large particles present in the water supply will usually be either inorganic sands or silts scale from pipe walls or well casings or organic materials such as weed seeds small fish eggs algae and so forth Inorganic particles are usually heavy and can easily be removed by a settling basin or a centrifugal sand separator Organic materials on the other hand are lighter and must be removed by a sand or screen filter of some type Floating materials may be skimmed from the water surface with a simple skim board Presence Of High Silt and Clay Loads A media filter may remove sand in water suppl

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