® Low-Volume Landscape Irrigation Design Manual
® Low-Volume Landscape Irrigation Design Manual Xerigation ®: Maximizing the effective use of every drop of water
© Copyright Rain Bird Sales, Inc., Landscape Drip Division 2000 Information contained in this manual is based upon generally accepted formulas, computation and trade practices. If any problems, difficulties or injuries should arise from or in connection with the use or application of this information or if there is any error herein, typographical or otherwise, Rain Bird Sales, Inc. and its subsidiaries and affiliates or any agent or employee thereof, shall not be responsible or liable therefor.
® FOREWORD Over the past four years, “Xerigation® Product, Design and Installation” seminars have been conducted across the U.S., in Mexico, Canada and even Europe. Rain Bird has talked to more than 1,000 irrigation professionals about landscape low-volume irrigation.
® CONTENTS 1 What is Xerigation®? .......................................................................... 1 Low-volume Irrigation ............................................................. 1 Benefits of Low-Volume Irrigation ......................................... 2 Selecting Low-Volume Irrigation ............................................ 4 Installation Cost ............................................................... 4 Size of Area ..........................................................
® Sparse Plantings ............................................................. 38 Selecting Emitters ..................................................... 39 Calculating the Wetted Area ................................... 40 Chapter Review ....................................................................... 41 Answer Key .................................................................... 42 6 7 8 9 10 Calculate System Run Time ........................................................... 43 1.
® 1 WHAT IS XERIGATION®? Xerigation is Rain Bird’s registered trademark term for a system that distributes water directly to plant root zones using Rain Bird’s low-volume, landscapespecific irrigation products. “Xerigation” is closely related to the word Xeriscape™, which refers to a landscape that conserves water by following the “Seven Principles of Xeriscape Landscaping.” These principles are: 1. Proper planning and design. 2. Soil analysis and improvement. 3. Practical turf areas. 4.
® TABLE 1-1: CONVENTIONAL VS. LOW-VOLUME IRRIGATION Design Installation Maintenance Conventional Irrigation (Spray Heads and Rotors) Low-Volume Irrigation (Xerigation) Design goal is to broadcast water as evenly as possible across an entire area. Water is delivered to the surface of the planted area. Design goal is to apply water to a uniform depth, either directly to the plant root zone or in a limited area. Water is delivered at or below the surface of the planted area.
® Improved Plant Health Low-volume irrigation can improve plant health. Figure 1-1 shows that the most active part of a plant’s root zone is the top half, which absorbs up to 70 percent of the plant’s water and nutrient intake. You will generally design your system to deliver 70 percent of the water to the upper half of the root zone and 30 percent to the lower root zone to encourage deep root development.
® Selecting Low-Volume Irrigation A Xerigation design is appropriate in any nongrass planting scheme where lowvolume irrigation can reduce water usage and improve plant health. Some of the factors that might affect your decision include installation cost, size of the area being irrigated, protection from vandalism, human safety and the type of maintenance that will be provided. Installation Cost In most cases, the cost of materials will be similar for low-volume and conventional irrigation systems.
® 2 THE DESIGN PROCESS An Innovative Approach Overhead, broadcast methods of irrigation are ideal for turfgrass, which requires a uniform precipitation rate over its entire planted area. However, the use of overhead irrigation in sparsely planted, nongrass areas causes water to fall on unplanted ground and is wasted, or worse yet, promotes weed growth. A conventional overhead system also is not the best approach for a mixed planting where some specimens need more water than others.
® The Xerigation Design Process Table 2-1 lists the major steps in the Xerigation design process described in this manual, along with a brief overview of each step. TABLE 2- 1: XERIGATION DESIGN PROCESS Page 6 Chapter 3 Gather accurate site data Collect information about the site to be irrigated and the plants in the site. Chapter 4 Determine plant water requirements Calculate the precise amount of water required by each plant or area of dense plantings. Chapter 5 Irrigate “base” plants (i.e.
® Individual Plants Versus Dense Plantings Throughout this manual, we will be drawing a distinction between sparse planting schemes (individual plants) and densely planted areas. For our purposes, dense plantings are those where the space between the plants’ mature canopies is less than two feet or where there is some type of ground cover. Figure 2-1 shows a typical sparse planting, while Figure 2-2 shows a typical dense planting.
® As you will see later in this manual, this distinction between sparse and dense planting schemes is important because the planting scheme strongly suggests which type of low-volume irrigation system design approach to take and which drip products to use. • Individual plants are generally irrigated by individual emission devices that supply a precise amount of water directly to the plant’s root zone (see Figure 2-3). These devices include single- and multi-outlet emitters, as well as micro-bubblers.
® 3 GATHER SITE DATA Accurate site data is important to any irrigation design, but with a low-volume approach it is even more critical because the water is distributed in smaller amounts. Your final design can only be as good as the site data you collect. Use the Site Data Worksheet (Figure 3-1) below to help you collect and organize site data. A full-size, reproducible blank worksheet is included in Appendix D of this manual.
® ➊ Site This section of the form is for identifying the site, recording information about Information the owner and making notes about local requirements for permits and system specifications. ➋ Water Source In this section of the worksheet, check off the type of water source (city water, well, surface water, or effluent). If a pump is used, indicate the type and its specifications. For all water sources, indicate the quality of the water based on the amount of particulate matter present.
® ➌ Soil Type Soil absorbs and holds water in much the same way as a sponge. A given type and volume of soil will hold a given amount of moisture. The ability of soil to hold moisture, and the amount of moisture it can hold, will greatly affect the irrigation design and irrigation schedule. Soil consists of sand, silt and clay particles and the percentage of each is what determines the soil type.
® Figure 3-2 shows the availability of water in soil for use by plants. Moisture held in soil is classified in three categories: • Hygroscopic water is water that is held too tightly in the soil to be used by plants. • Capillary water is water that is held in the pore spaces of the soil and can be used by plants. • Gravitational water drains rapidly from the soil and so is not readily available to be used by plants.
® Table 3-3 shows the way water is absorbed in the three different soil types: • • • • Maximum infiltration rate indicates how fast water can be absorbed into the soil without runoff. Wetting patterns show the relationship between vertical and horizontal movement of water in the soil up to the maximum wetted diameter. Once the maximum wetted diameter is reached, water movement is downward, forming the traditional “carrot,” “onion,” and “radish” profiles.
® TABLE 3- 4: PET RATES BASED ON CLIMATE Climate Definition (mid-summer) PET (worst case, inches per day) Application Efficiency Cool Humid <70° F >50% humidity .10 - .15 95% Cool Dry <70° F <50% humidity .15 - .20 95% Warm Humid 70° - 90° F >50% humidity .15 - .20 90% Warm Dry 70° - 90° F <50% humidity .20 - .25 90% Hot Humid >90° F >50% humidity .20 - .30 85% Hot Dry >90° F <50% humidity .30 - .
® On your Site Data Worksheet, enter a general description of the plants in each hydrozone, such as “mixed ground cover and shrubs.” In some cases, this information will come from the planting plan; in other cases, you will collect the data from an actual site survey. Also, describe the planting density in each hydrozone, this will strongly influence the selection of emission devices. For each hydrozone, enter the irrigation method to be used.
® Figure 3-3: Sample Plot Plan—Doyle Residence , E N S Hydrozone W Ground Cover GARAGE Gravel Walkways FENCE Concrete M Water Meter C Container Plant H Hanging Plant TURF VEG.
® Figure 3-4: Sample Site Data Worksheet—Doyle Residence DATE JOB NUMBER SITE DATA WORKSHEET ➋ Water Source ❶ Site Information John & Wendy Doyle Name Address City Contact Day Phone 7836 Connor Lane Brighton John 714-555-8136 State CA Zip 92867 Eve. Phone 714-555-1089 Well: Sub Centrifugal PSI HP GPM Hydrozone 9, vegetable garden, not yet planted.
® Answer Key Check your answers to the review items with the correct answers below. 1. PET = .20 - .25 inches per day 2. Application efficiency = 90% 3. Hydrozone 7: Dense plantings 4.
® 4 DETERMINE PLANT WATER REQUIREMENTS The goal of Xerigation design is to apply water efficiently and effectively to each plant or group of plants in the landscape. To do this, you will need to estimate the daily water requirements of the various plant material in your landscape. Individual, sparsely arranged plants will be irrigated by individual emitters or individual micro-bubblers. The water requirement for these plants is measured in gallons per day.
® Figure 4-1: LOW-VOLUME DESIGN WORKSHEET: DENSE HYDROZONE Dense Hydrozone 1 Design Worksheet Address State City Zip Contact 12" Ground Cover/Trees 18" Ground Cover /Shrubs 24" Ground Cover/Shrubs/Trees 36" Coarse SYSTEM RUN TIME 5 Base Plant Medium Ground Cover Fine Shrubs 3 Base Plant SPECIES FACTOR BASE PLANT SPECIES DESCRIPTION Shrubs Only Application Efficiency 2 HYDROZONE Shrubs/Trees Daily PET (inches per day) Soil Type: Ground Cover Only Eve.
® Calculating Water Requirements ∂ Gather Site Begin by filling in the identifying information about the site and the hydrozone Information at the top of the worksheet. Transfer the Daily PET, Application Efficiency, and Soil Type from the Dense Hydrozone Worksheet (Figure 7-1 at the end of Chapter 7) to the appropriate places on the dense and sparse hydrozone worksheets (Figures 4-1 and 4-2, page 20).
® Species Factor The species factor is an adjustment to PET that reflects the amount of water that a particular species of plant needs relative to turf grass. The range can be from 0.2 for plants like cactus and succulents that require little water, up to 0.9 for plants like ferns that require a great deal of water. On the dense hydrozone worksheet (Figure 4-1, page 20), indicate the estimated range of the plant’s species factor: “low,” “average” or “high” based on Table 4-2 below.
® EXAMPLE Assume that you have a hydrozone that contains only sparsely planted shrubs. Locate the row labeled “Shrubs,” and read across to the “Low” column. You’ll find that the density factor for this plant is 0.5. “Low” would be entered in the top half of the “density factor” box on your worksheet and “0.5” would be entered in the bottom half of the box. Microclimate Factor A microclimate is a sub-climate. Even small residential sites will have areas with entirely different climatic conditions.
® Kc Once you have collected all the information about the plants in the hydrozone, and assigned the values for species, density, and microclimate factors, you can calculate the Kc for each plant. Kc indicates the plant’s need for water as it relates to the established PET rate in the area. To calculate the Kc values, simply multiply each plant’s species factor, density factor, and microclimate factor. Round this number to the nearest tenth, and record it in the “Kc” column of the worksheet.
® Area of Plant Canopy Use the following formula to determine the area of the plant’s canopy. Canopy Area (sq. ft.) = .7854 x Diameter (ft.) x Diameter (ft.) EXAMPLE You are calculating the area of the root zone for a large shrub. The mature canopy of the shrub is 6.5 feet in diameter. To calculate the area, you multiply: .7854 x 6.5 ft. x 6.5 ft. = 33.18315 sq. ft. After rounding to the nearest tenth, you find that the area of the root zone is 33.2 sq. ft.
® Chapter 4 Review To check your understanding of the material covered in Chapter 4, complete this review. The review is based on the partially completed hydrozone worksheet which is located at the end of Chapter 7. Page 26 1. The worksheet indicates that the base plant is a ground cover: Ice Plant. Using the information in the sample worksheet, and Tables 4-2 through 4-4, calculate the Kc for the ice plant. 2. The non-base plants in this hydrozone include two ferns. Calculate the Kc for the ferns.
® Answer Key Check your answers to the review items with the correct answers below. 1. Species Factor = 0.2 Density Factor = 1.1 Microclimate Factor = 1.2 Kc = 0.3 2. Species Factor = 0.7 Density Factor = 0.5 Microclimate Factor = 1.3 Kc = 0.5 3. Water requirement = 0.06 inches per day 4. Canopy Area = 19.6 square feet Water Requirement = 1.
® Page 28 Chapter 4
® 5 IRRIGATE BASE PLANTS In this chapter, you will: 1. Identify the hydrozone’s base plant. 2. Select emission devices for the base plant. This chapter will continue to use the Hydrozone Design Worksheets introduced in the previous chapter. Use the sample worksheet at the end of Chapter 7 as a reference while reading this chapter. Identifying the Base Plant If you have not already identified the base plant, you must do so now.
® ➍ Emission Devices To select the best emission device or devices to irrigate the base plant, start by considering the following: • Types of Plants. As we have already seen, the primary factor that affects your design is the water requirement of the individual plants or groups of plants in the landscape. • Intended Use. Factors such as traffic and the threat of vandalism will affect your choice of distribution components and emission devices.
® • Cost. The equipment cost for low-volume systems is generally lower than conventional systems. However, in many cases the installation cost will be higher for commercial drip systems and lower for residential low-volume systems. This is because commercial drip systems tend to be installed on either buried PVC or high-density polyethyelene tubing.
® TABLE 5-1: XERIGATION EMISSION DEVICE APPLICATION MATRIX Planting Scheme Dense Sparse Emission Device* Application Outlets Pressure Compensates Flow Rate Filter Included Filter Required Inlet Ground cover, beds, mass shrub plantings Landscape Dripline 12", 18", 24" spacing Yes 0.6, 0.
® Landscape Dripline is a closed-loop grid of inline emitter tubing that, when properly spaced, delivers full coverage to a planting area (see Figure 5-1). The soil type and planting scheme influence which flow rate, emitter/lateral spacing, length of lateral and configuration you choose.
® Table 5-2 shows Landscape Dripline’s selection of flow rates, spacings and coil lengths for a variety of conditions. TABLE 5-2: LANDSCAPE DRIPLINE CHOICES Model Flow Rate Emitter Spacing Length of Tubing LD06-12-100 0.6 GPH 12" 100' LD06-12-250 0.6 GPH 12" 250' LD06-12-500 0.6 GPH 12" 500' LD06-18-100 0.6 GPH 18" 100' LD06-18-250 0.6 GPH 18" 250' LD06-18-500 0.6 GPH 18" 500' LD06-24-100 0.6 GPH 24" 100' LD06-24-500 0.6 GPH 24" 500' LD09-12-100 0.
® Use the worksheet below to determine actual lateral spacing. LATERAL LINE SPACING WORKSHEET Follow the example below to determine the space between lateral lines: To Get This: Do This: Calculations Totals 1. Width of the planted area Measure the width in feet 5 feet 2. Width of planted area in inches: Multiply feet by 12 to get inches 5' x 12" = 60 inches 3. Actual width of the grid: Subtract edge offset (multiply 2 x 2 = 4)* 60" - 4" = 56 inches 4. No.
® Landscape Dripline: A More Technical Approach The preceding information about selecting the appropriate inline emitter flow rate and spacing for the proper design of a Landscape Dripline grid was based primarily on identifying the soil type of the planting area. In this section, we add one more factor to the selection criteria: the desired watering depth based on the plants’ root zones.
® However, there is a limit to the horizontal spread of water by capillary action in the soil even when that soil has been well amended and is consistent throughout the planting area. As a result, you must be careful not to exceed the maximum allowable spacing of the emitters as shown in Table 5-5. If this maximum spacing is exceeded, dry spots between emitters will result and it is likely that salts will build up around the plants’ roots.
® Xeri-Sprays Rain Bird’s Xeri-Sprays (max. flow 31 GPH at 30 PSI) have higher flow rates than most drip emitters, but lower flow rates than conventional sprays (up to 216 GPH). They are best suited to irrigating large, densely planted areas such as large areas of ground cover. Avoid using Xeri-Sprays in windy conditions. Xeri-Sprays should be placed head-to-head to allow for at least a 50% overlap of the spray patterns. Xeri-Sprays will provide, on average, approximately one inch per hour of water.
® Selecting Emitters In general, use Table 5-7 below to guide your emission device selection. Remember that the less coarse or sandy the soil is, the more possibility of runoff. The more water a plant needs on a daily basis, the greater the need for higher flow emission devices to avoid installing an inordinate number of low-flow emitters. To address this challenge, consider the use of wells or troughs to capture the higher flow that exceeds the infiltration rate of the soil.
® Calculating the Given your soil type, select the appropriate emission device to avoid runoff. Wetted Area Next, determine the suggested spacing of your emitters based on the soil type and the desired watering depth. Use Tables 5-4 through 5-6 as a guideline. Next determine the area wetted by each of your emitters. The formula for the area wetted is: Area Wetted (sq. ft.) = Emitter Spacing (ft.) × Emitter Spacing (ft.) × 0.
® EXAMPLE The minimum area to be wetted for each 4-foot azalea is 6.3 square feet. This is because the area of the root zone is estimated as: .7854 x diameter x diameter or .7854 x 4 x 4 = 12.6 sq. ft. The minimum area that should be wetted is 50 percent of the root zone or 1/2 x 12.6 = 6.3 sq. ft. Dividing this by the area wetted by each emitter (1.8 square feet) tells us that we will need at least four emitters for each azalea.
® Answer Key Check your answers to the review items with the correct answers below. 1. Lowest 2. a. Sparse b. Sparse c. Dense d. Sparse e. Dense 3. a. 0.9 GPH/12" spacing b. 0.9 GPH/18” spacing c. 0.6 GPH/24” spacing 4. Emitter and lateral spacing = 18 inches 5. Number of rows = 11 rows Spacing between rows = 11.
® 6 CALCULATE SYSTEM RUN TIME The system run time is determined by the base plant. Since the base plant is the plant that requires the least amount of water, you will run the system only long enough to supply the correct amount of water to the base plant. In the next chapter, you will determine the flow rates for the non-base plants as well as the best-suited emission devices to achieve these flow rates.
® 1.Calculate System Run Time The general formula for system run time is: Run Time Per Day = Water Requirement Flow Rate However, since the water requirements are measured differently, you will apply this general formula in slightly different ways for dense and sparse plantings. Dense Plantings In Chapter 4, you calculated the water requirement for dense plantings in inches per day (also see Appendix B). In order to calculate the system run time, you must also measure the flow in inches per hour.
® To calculate the system run time for densely planted base plants, use the following variation of the general formula: Run Time Per Day (hours) = Water Requirement (inches per day) Adjusted EDR (inches per hour) Most irrigation controllers are set in minutes, so you must convert to minutes by multiplying run time (in hours) by 60. EXAMPLE You determine that the water requirement for the base plants in your hydrozone is 0.2 inches per day based on the formula in Chapter 4 and Appendix B.
® 2.Determine Maximum Run Time The maximum system run time is the length of time the system can run before you begin to waste water due to deep percolation loss below the desired watering depth. To determine the maximum system run time, you must know the flow rates of the emitters and the allowable depletion of the soil. Allowable depletion is the percentage of soil moisture that you will allow the plants to deplete before watering again.
® TABLE 6- 3: MAXIMUM SYSTEM RUN TIME FOR MEDIUM SOIL Watering Depth Emitter Spacing 3 inches Emitter Flow (GPH) Maximum Run Time Use Xeri-Sprays or Xeri-Pops 6 inches 12 inches 0.5 1.0 2.0 26 minutes 13 minutes 7 minutes 9 inches 18 inches 0.5 1.0 2.0 89 minutes 45 minutes 22 minutes 12 inches 24 inches 0.5 1.0 2.0 211 minutes 106 minutes 53 minutes 18 inches 36 inches 0.5 1.0 2.0 713 minutes 357 minutes 178 minutes 24 inches 48 inches Use individual emitters based on plant needs.
® 3.Determine Irrigation Interval The first task in determining the irrigation interval is to compare your calculated system run time per day to the maximum run time. In most cases the calculated run time per day will be less than the maximum run time, and you can use the following formula to determine the maximum irrigation interval: Maximum Irrigation Interval (days) = Maximum Run Time Calculated Run Time Per Day EXAMPLE: You are irrigating to a depth of 18 inches in coarse soil with 1.0␣ GPH emitters.
® Chapter Review To check your understanding of the material covered in Chapter 6, complete this review. The review is based on the partially completed hydrozone worksheet (Figure 7-1) which is located at the end of Chapter 7. 1. We have determined that we will use Landscape Dripline with 0.6 GPH emitters spaced at 12" to irrigate the base plant in hydrozone 7. Use Table 6-1 to determine the EDR. 2. Calculate the Adjusted EDR by multiplying the EDR by the application efficiency. 3.
® Answer Key Check your answers to the review items with the correct answers below. 1. EDR = 0.96 2. Adjusted EDR = 0.888 X .90 = 0.86 inches per day 3. System Run Time = 4.2 minutes per day 4. Maximum Run Time = approximately 26 minutes. 5. Maximum Irrigation Interval = 6 days 6. Irrigation cycle: 8.
® 7 IRRIGATE NON-BASE PLANTS In earlier chapters, you determined the base plant for your hydrozone: the plant with the smallest daily water requirement. You then selected emission devices to irrigate the base plant and calculated the system run time based on the emission devices you chose. In this chapter, you will select emission devices for the non-base plants in the hydrozone.
® TABLE 7-1: EMISSION DEVICE FLOW RATES Emission Device Available Flow Rates Xeri-Bug Single Outlet Pressure Compensating Emitter 0.5, 1.0, 2.0 GPH Shrub Xeri-Bug Single Outlet Pressure Compensating Emitter 1.0, 2.0 GPH Pressure Compensating Modules 5.0, 7.0, 10.0, 12.0,18.0, 24.0 GPH Multi-Outlet Xeri-Bug; Multi-Outlet 1.0 GPH per outlet (up to 6 outlets) Shrub Xeri-Bug Xeri-Bubblers Streams: 0-13.0 GPH, Umbrella: 0-35.0 GPH Xeri-Sprays 0-31.0 GPH Landscape Dripline 0.6, 0.
® LOW-VOLUME DESIGN WORKSHEET: DENSE HYDROZONE 1 Site Information Name John & Wendy Doyle Address 7836 Connor Lane City Brighton John Day Phone 714-555-8136 Daily PET (inches per day) Eve. Phone Zip 92867 Ground Cover /Shrubs Ground Cover/Shrubs/Trees 714-555-1089 18" 6" 24" 9" 36" HYDROZONE 7 DESCRIPTION Mixed G. C. & shrubs Emitter Spacing Shrubs Only Coarse 3" 12" Shrubs/Trees 0.
® Answer Key Check your answers to the review items with the correct answers below. Page 54 1. Total flow = 20 GPH 2.
® 8 SYSTEM LAYOUT System layout for low-volume hydrozones is relatively easy. Once you have determined the type, number and spacing of emission devices required for each plant or group of plants, simply determine the most cost-effective way to connect the various emission devices to the water source. However, you must also be certain not to exceed the hydraulic constraints of the system components. (See Chapter 9 for information on hydraulics.
® Xeri-Tube 700 Rigid PVC Pipe Emission devices Xeri-Tube 700 Distribution tubing on multi-outlet emitter Figure 8-2: Emitter layout options ❘ ▼ Figure 8-3: Layout using poly drip tubing (Xeri-Tube 700) Figure 8-4: Layout using rigid PVC Page 56 Chapter 8
® Using Inline Tubing When using Landscape Dripline, remember that the spacing of the emitters is determined primarily by the soil type. To maximize water savings and prevent water waste below the root zone, consider the area of the root zone as well as the recommended watering depth. Lay out the rows so the emitters themselves form a triangular or square pattern. When possible, lay out the inline tubing so that it forms a loop, with water flowing in two directions from the water source.
® ▲ Dense ground cover planting (shown in gray) irrigated with Landscape Dripline. Manual flush valve ▲ Rain Bird Control Zone Kit XCZ-075 (3/4”) Sparse shrub planting (shown in white) irrigated with supplemental single-outlet emitters connected to Rain Bird Landscape Dripline tubing. Emitters use Rain Bird 1/4” distribution tubing, TS-025 stakes and DBC-025 bug caps.
® System Configuration Filtration When a significant distance exists between the system's primary filter and the Landscape Dripline grid, Rain Bird's Control Zone Kit should be installed. The Control Zone Kit filter acts as a secondary filter to protect the Landscape Dripline grid against contamination that could be caused by a break in the sub-main. The kit consists of a ball valve, 200-mesh Y-filter, remote control valve (or anti-siphon valve), 3/4" pressure regulator and Schedule 80 close nipples.
® Water Meter Approved Backflow Preventer Automatic Filter Kit or Rotary Disk Filter (optional for large systems) PVC Main Line Control Zone Kit: Shut-Off Ball Valve 120-Mesh Filter Filter Electric Control Valve Pressure Regulator Landscape Dripline Laterals Polyethylene or PVC Header ManualEnd Flush Valve Tubing Closure End Feed Center Feed Figure 8-7: Landscape Dripline system configuration Page 60 Chapter 8
® Irrigating Slopes On a slope, without correct emitter placement, water will percolate downhill and out of the root zone. When installing emitters on a slope, place them above the plants so that the wetting pattern remains within the root zone. Figures 8-8 and 8-9 illustrate the correct placement of emitters and lateral pipes on a slope.
® Container Plants Low-volume irrigation can also be used to water container plants. Run the 1/4" distribution tubing up through the bottom of the container whenever possible and attach either emitters or micro-bubblers to automatically apply exactly the right amount of water. Be careful not to pinch the tubing closed. Figures 8-11 and 8-12 illustrate two possible applications.
® 9 SYSTEM HYDRAULICS Chapter 3 covered gathering site data and Chapters 4 - 8 described how to design and lay out your low-volume irrigation system. This chapter covers system hydraulics, the final step in the design process. The main goal of determining system hydraulics is to assure that there is sufficient flow and water pressure available to irrigate all parts of the landscape.
® In Figure 9-1, the distance from the water’s surface to ground level is 160 feet. To find the static pressure at ground level, you would multiply .433 by 160 to get 69.28 PSI. 160’ Figure 9-1: Determining static pressure based on elevation Calculating Pressure Loss Flow To calculate pressure losses, you need to know the total flow required by the hydrozone (in GPH or GPM).
® Sparsely Planted Hydrozones In a sparsely planted hydrozone, where you have used individual emitters or micro-bubblers to irrigate plants, you’ll need to add up the total flow required by all the emission devices in the hydrozone. You may want to use a worksheet similar to the one below (Figure 9-2) to calculate the total flow in a sparsely planted hydrozone.
® EXAMPLE Assume that you have a sparsely planted hydrozone with mixed types of shrubs and one large tree. Each of the shrubs require two emitters, either 1/2 or 1 GPH. The large tree requires four 10-GPH emitters. The worksheet for this hydrozone might look like the sample below. COMPLETED TOTAL FLOW WORKSHEET Emission Device Flow Rate Number of Emission Devices Flow (GPH) 20 x 0.5 GPH = 34 x 1.0 GPH = 4 10.0 34.0 x 2.0 GPH = x 5.0 GPH = x 7.0 GPH = x 10.0 GPH = x 13.
® Densely Planted Hydrozones In a densely planted area where you have designed a Landscape Dripline grid, use the Flow Rate Worksheet below to determine the total flow through your grid. If you have any supplemental emitters, be sure to add in their adjusted flows as well. For this example, we will assume coarse soil and will therefore specify Landscape Dripline model LD-09-12-500 (0.9 GPH, 12" spacing, 500’ coil).
® Determine Maximum Lateral Lengths The maximum length of a Landscape Dripline lateral is determined by the maximum allowable pressure loss. The minimum inlet pressure should be 15 PSI. As long as you meet this requirement, there is no need to calculate friction loss in the Landscape Dripline lateral lines. Simply use Table 9-2 to determine the maximum lateral lengths.
® When supplemental emitters are added to the grid, the additional flow affects the maximum length of the lateral lines and should be taken into consideration. See Chapter 8, “Placing Supplemental Emitters.
® TABLE 9-4: MINIMUM/MAXIMUM FLOWS FOR PROPER VALVE PERFORMANCE Flow GPM XACZ-075 PSI GPH XCZ-075 PSI 75-DVX PSI XCZ-100 PSI 1 60 5.1 3.5 2.5 1.0 3 180 5.1 3.5 2.5 1.0 5 300 5.4 3.6 2.9 1.2 10* 600 9.9 7.5 3.8 5.1 15* 900 15.9 12.7 4.2 8.8 20* 1200 24.2 20.2 5.1 14.3 100-PEB * PSI 3.0 2.6 2.0 1.5 2.0 2.5 XCZ-075 pressure loss data above 5 GPM is with PSI-M30X pressure regulator. Maximum flow rate with "M" style regulators is 22 GPM.
® TABLE 9- 6: FRICTION LOSS CHARACTERISTICS OF XERI -TUBE 700 PSI LOSS PER 100 FEET OF TUBE (PSI/100FT) C = 140 Outside Diameter = 0.700" Inside Diameter = 0.580" Flow (GPM)* Velocity (FPS) PSI Loss** 0.5 0.61 0.19 1.0 1.21 0.69 1.5 1.82 1.45 2.0 2.43 2.47 2.5 3.03 3.74 3.0 3.64 5.24 3.5 4.24 6.97 4.0 4.85 8.93 *Flows greater than 4.1 GPM (5 FPS) are not recommended. **Does not include pressure loss due to emitter barbs.
® TABLE 9-7: RAIN BIRD PRESSURE REGULATORS Model Size Outlet Pressure Label Color Flow Range PSI-L30X-075 3/4" 30 PSI/2,0 BARS Red 0.1-5.0 GPM PSI-M30X-075 3/4" 30 PSI/2,0 BARS Yellow 2.0-22.0 GPM PSI-M40X-075 3/4" 40 PSI/2,8 BARS Yellow 2.0-22.0 GPM PSI-M50X-075 3/4" 50 PSI/3,5 BARS Yellow 2.0-22.0 GPM PSI-M40X-100 1" 40 PSI/2,8 BARS N/A 2.0-22.0 GPM PSI-M50X-100 1" 50 PSI/3,5 BARS N/A 2.0-22.
® 10 INSTALLATION, MAINTENANCE AND TROUBLESHOOTING Installation Installation of low-volume irrigation components, while slightly different from conventional-system installation, is a straight forward process. The following steps define a typical low-volume installation. 1. Analyze the site. Compare the site to your irrigation plan and note any obstructions or discrepancies. Modify your plan to reflect actual site conditions. 2. Locate or mark components.
® 12. Layout XT-700 poly drip tubing or Landscape Dripline using fittings as needed. Warm the tubing in the sun before installing to make it more flexible. Don’t pull tubing too tight; allow for expansion and contraction due to changing weather conditions. 13. Flush the line to remove debris. 14. Attach emission devices. 15. Staple XT-700 poly drip tubing or Landscape Dripline to grade. 16. Finish grade. 17. Plant ground cover. 18.
® TABLE 10-1: RECOMMENDED MAINTENANCE Interval Action Design/Installation phase Consider accessibility of valves, filters, and emission devices to maintenance personnel. During installation, make sure components are placed for easy access. Completely flush the system prior to operation to remove all debris. Be especially careful to keep pipe shavings and burrs from rigid PVC tubing out of the lines. After two weeks of operation Inspect and clean all filters.
® TABLE 10-2: TROUBLE SHOOTING Problem Potential Cause/Solution • Wrong valve selected, flow too low. Replace with correct size Xerigation Control Zone. • Valve diaphragm is contaminated. Clean or replace diaphragm. • Solenoid faulty or wire severed. Check wiring. Repair or replace solenoid. • Line severed upstream of emission device. Check for breaks and repair. • Filter clogged or inadequate. Check, clean, or replace filter. • Emission device clogged or faulty. Replace emission device.
® A FORMULAS FOR XERIGATION DESIGN Kc is an adjustment factor to PET that accounts for the needs of a specific plant in specific growing conditions. It is also known as the “crop coefficient” or the “plant factor.” The formula for Kc is: Kc = Species Factor x Density Factor x Microclimate Factor Water Require- The water requirement for a densely planted hydrozone is measured in inches ment For a Dense per day.
® Water Require- The water requirement for an individual plant is measured in gallons per day. ment For a Sparse Planting Scheme The formula for the water requirement for an individual plant is: Water Requirement (GPD) = .
® Irrigation Interval Once you calculate the system run time and the maximum run time, you can determine how often to run the system. Maximum Irrigation Interval (days) = Maximum Run Time Calculated Run Time The general formula for system run time is: Run Time (hours) = Water Requirement Flow However, since the water requirements are measured differently for sparse plantings and dense plantings, you must apply the formula differently.
® The result can be converted from hours to minutes by multiplying it by 60 minutes. Sparse Planting Scheme The formula for system run time for a sparse planting scheme is shown below. The water requirement of the base plant must be used and is measured in gallons per day: Run Time (hours) = Water Requirement (gallon per day) Total Flow at Base Plant (GPH) Number of The number of emission devices required for an individual plant will depend on Emitters the following: • • • Area of root zone.
® B PET DATA Colorado Alabama Idaho Birmingham .20 Alamosa .15 Boise .24 Montgomery .21 Denver .18 Lewiston .23 Mobile .20 Pueblo .20 Pocatello .22 Connecticut Alaska Illinois Anchorage .16 Hartford .20 Chicago .19 Fairbanks .20 New Haven .20 Peoria .20 Springfield .21 Delaware Arizona Flagstaff .23 Phoenix .30 Tuscon .27 Arkansas Wilmington .20 Florida Evansville .21 Fort Meyers .24 Fort Wayne .20 Jacksonville .25 Indianapolis .21 South Bend .
® Louisiana Montana New Mexico Baton Rouge .20 Billings .24 Albuquerque .30 Alexandria .20 Glasgow .23 Carlsbad .31 New Orleans .20 Helena .20 Clovis .27 Miles City .24 Las Cruces .33 Missoula .20 Maine Caribou .13 Portland .16 Maryland Baltimore .16 Massachusetts Nebraska New York Albany .16 Norfolk .20 Buffalo .15 North Platte .20 New York .19 Omaha .23 Syracuse .15 Boston .20 Scottsbluff .25 North Carolina Pittsfield .19 Valentine .
® Texas Oregon Washington La Grande .20 Abilene .28 Aberdeen .13 Portland .18 Amarillo .27 Seattle .15 Roseburg .20 El Paso .29 Spokane .19 Fort Worth .28 Yakima .20 Pennsylvania Erie .16 Houston .27 West Virginia Harrisburg .17 Laredo .30 Charleston .16 Philadelphia .20 San Antonio .27 Clarksburg .15 Pittsburgh .18 Rhode Island Providence .19 South Carolina Charleston .19 Columbia .20 Spartanburg .18 South Dakota Utah Wisconsin Salt Lake City .
® Page 84 Appendix B
® C FRICTION LOSS AND PERFORMANCE DATA Landscape Dripline Control Zone Kit Friction Loss Characteristics METRIC METRIC Model Flow GPH Spacing in. Coil Length ft. Model Flow l/h Spacing cm Coil Length m Flow GPM GPH XACZ-075 XCZ-075 75-DVX psi psi psi XCZ-100 psi Flow m3⁄h l/h l/s XACZ-075 XCZ-075 75-DVX XCZ-100 Bars Bars Bars Bars LD-06-12-100 LD-06-12-500 LD-09-12-100 LD-09-12-500 LD-06-18-100 LD-06-18-500 LD-09-18-100 LD-09-18-500 LD-06-24-100 LD-06-24-500 LD-09-24-100 LD-09-24-500 .
® 1/4" Distribution Tubing Friction Loss Characteristics In-Line WYE Filter METRIC METRIC O.D. 6 mm I.D. 4 mm O.D. .220" I.D. .160" Flow GPH Velocity fps psi Loss Flow m3⁄h l/h 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 25 30 0.27 0.53 0.80 1.06 1.33 1.59 1.86 2.13 2.39 2.66 2.92 3.19 3.45 3.72 3.98 4.25 4.52 4.78 5.05 5.31 6.64 7.97 0.16 0.59 1.24 2.12 3.20 4.49 5.97 7.64 9.50 11.54 13.79 16.17 18.75 21.50 24.43 27.53 30.80 34.23 37.83 41.60 62.86 88.
® D XERIGATION PLANNING FORMS Photocopy the planning forms on the following pages and use them to help you plan your Xerigation projects.
® Name No No State Eve.
# DESCRIPTION Hydrozones (Attach sketch of property) DENSITY IRRIGATION METHOD ® Xerigation Planning Forms Page 89
® 1 DENSITY FACTOR Zip MICROCLIMATE FACTOR 3 Soil Type: Kc Coarse Medium Fine PLANT DIAMETER (FT.) CANOPY AREA (SQ. FT.) WATER REQUIREMENT (GPD) 5 TYPE 4 6 FLOW HYDROZONE DATE JOB NUMBER 1 DESCRIPTION Water Requirement SPACING = Gallons per Day (GPD) QUANTITY EMISSION DEVICES Application Efficiency .623 ✕ Area ✕ Kc ✕ PET SYSTEM RUN TIME LOW-VOLUME DESIGN WORKSHEET: SPARSE HYDROZONE State Eve.
ADDITIONAL PLANT SPECIES SPECIES FACTOR DENSITY FACTOR MICROCLIMATE FACTOR Kc PLANT DIAMETER (FT.) CANOPY AREA (SQ. FT.
® CA Zip 92867 714-555-1089 Kc Planting Scheme Ground Cover Only Ground Cover/Trees Ground Cover /Shrubs 4 4 9" 6" 3" 36" 24" 18" 12" 12" Emitter Spacing 18" 24" SYSTEM RUN TIME Mixed G. C. & shrubs DESCRIPTION 7 HYDROZONE DATE JOB NUMBER 1 5 QUANTITY 36" Water Requirement Kc × PET = Inches per Day FLOW 2 per ADJUSTED EDR TYPE 7.
ADDITIONAL PLANT SPECIES SPECIES FACTOR DENSITY FACTOR MICROCLIMATE FACTOR Kc PLANT DIAMETER (FT.) CANOPY AREA (SQ. FT.
® FLOW RATE WORKSHEET 3. No. of emitters in the zone: 2. Length of tubing in inches: 1. Length of tubing in feet: Round up to next whole number Divide length by emitter spacing (12", 18", 24") Multiply feet by 12 to get inches Determine the total length in feet from grid Calculations Use the worksheet below to determine the flow rate for your system: 4. Total no. of emitters: Multiply no. of emitters by flow rate (0.6 or 0.9 GPH) Do This: 5.
® GLOSSARY E 1/2" polyethylene a low-volume distribution component typically used to bring water from a Schedule 80 tubing riser into a hydrozone. 1/4" distribution a low-volume distribution component typically used to bring water directly to plant root tubing zones; also known as “spaghetti” tubing.
® distribution tubing See 1/4" distribution tubing. drip emitter a low-volume emission device that delivers water at low flow rates, one drip at a time; drip emitters are used to apply water directly to an individual plant root zone. emission device a low-volume irrigation component that delivers water directly to the plants; emission devices can include bubblers, drip emitters, microsprays and inline emitter tubing.
® microclimate a small sub-climate within a project site created by adjacent hardscape, a shade tree or exposure. micro-spray a low-volume emission device that operates similarly to a conventional sprayhead, but much lower flow rates; microsprays are used to water an entire hydrozone rather than individual plant root zones. mixed hydrozone a hydrozone in which the plants have different water needs.
® soil types, continued —loam soil having a mixture of the different grades of sand, silt and clay in such proportion tha none of the characteristics predominate; it is mellow with a somewhat gritty feel, and when moist is slightly plastic. Squeezed when dry, it will form a cast that will bear careful handling; the cast formed by squeezing the moist soil can be handled quite freely without breaking. —sand a loose and single-grained soil; the individual grains can easily be seen or felt.
® F XERIGATION PRODUCT LINE See the Rain Bird Landscape Irrigation Products Catalogfor more information. XERIGATION EMISSION DEVICES Xeri-Bug™ Emitter—Available in 0.5, 1.0, and 2.0 GPH flow rates, pressure compensating. (XB-05, XB-10, XB-20). Shrub Xeri-Bug™ Emitter—Available in 1.0 and 2.0 GPH flow rates, pressure compensating. Adapts to a standard 1/2” riser (XBT-10, XBT-20). Pressure-Compensating Modules—Available flow rates: 5 GPH to 24 GPH (PC-05, PC-07, PC-10, PC-12, PC-18, PC-24).
® XERIGATION CONTROL ZONE COMPONENTS Xerigation Control Zone Kit—Prepackaged kit includes Ball Valve, Inline Filter, Remote Control Valve, Pressure Regulator, and 3/4” Schedule 80 Nipples (XCZ-075, XCZ-100). With anti-syphon valve use model (075-ASVF), With commercial PEB valve, use XCZ-100COM. 3/4” DVX Remote Control Valve—(75-DVX). Handles flow from 12 to 900 GPH. In-line WYE Filters—Available in 3/4" (RBY-075-200X) or 1" (RBY-100-200X).
® XERIGATION DISTRIBUTION COMPONENTS 1800 Xeri-Bubbler Adapter—Allows Xeri-Bubblers to be installed on a Rain Bird 1800 Series Sprinkler. (XBA-1800). 12" Polyflex Riser—Used in conjunction with Polyflex Riser Adapter (FRA050) or Flex Riser Stake (RS-025T). Accepts all Xeri-Bubbler and Xeri-Spray emission devices. (PFR-12). Threaded Adapter—1/2” FPT inlet screws onto any 1/2” NPT riser. Accepts all Xeri-Bubbler and Xeri-Spray Emission Devices. (10-32A).
® DISTRIBUTION COMPONENTS CONTINUED 1/4" Distribution Tubing—Available in 50 and 100 foot coils (DT-025-050 and DT-025-100) or 1500 foot reel (DT-025-1500). 1/4" Barb Transfer Fittings—Used to connect 1/4” distribution tubing (DT-025) together. 1/4” Barb Connector (BF-1), 1/4” Barb x Barb EII (BF-2), and 1/4” Barb x Barb x Barb Tee (BF-3). LOC Fittings—Elbow, coupling and tee. Works with 600 and 700 series tubing. O ring design for leak-free connections. Universal Fittings—Elbow, coupling and tee.
® INSTALLATION DETAILS Installation details for Xerigation products can be downloaded from Rain Bird’s website at: www.rainbird.com. 1. From the Rain Bird home page, click on Landscape Drip. 2. From the Xerigation home page, click on Technical Information. 3. From the Technical Information page, click on Download Files. 4. From the Download Technical Information page, follow the instructions and click on the appropriate file type (xeri.exe, jxeri.exe, wxeri.exe, dxeri.exe) under the Xerigation category.
® BIBLIOGRAPHY Drip Irrigation Design for Landscapes, by Joseph Y. T. Hung, Paper Number 88-2066 presented at the American Society of Agricultural Engineers, Rapid City, SD, 1988. Determining Drip Emitter Spacing and Watering Time for Maximum Water Use Efficiency, by Joseph Y. T. Hung, Paper presented at the Irrigation Association, San Diego, CA, 1993.
® INDEX —A— Adjusted EDR, 44 Allowable depletion, 46 Application efficiency, 14, 17, 25, 44 Application, emission device, 30 Area canopy, 39 mature canopy, 40 minimum to be wetted, 40 plant canopy, 25 root zone, 39 wetted per emitter, 40 Available water, 12 —B— Base plant, 29 dense hydrozone, 21 irrigating, 29 sparse hydrozone, 29, 38 —C— Canopy, mature, 25 Capillary action, 11 City water, 10 Clay, 11 Climate, 11 Coefficient, crop, 21 Container plants, irrigating, 62 Control zone, 14, 69 Controller, 45 C
® —M— Maintenance, 74 Maximum emission device spacing, 37 Maximum infiltration rate, 13 Maximum lateral lengths, 68 Maximum system run time, 46 Maximum wetted diameter, 13 Maximum wetting patterns, 13 Mesh, 10 Meter, water, 10 Microclimate, 23 Microclimate factor, 23 Micro-sprays, 32, 43 Minimum area to be wetted, 40 Minimum desired watering depth, 36 Minimum watering depth, 36 Multi-outlet Shrub Xeri-Bug, 32, 52 Multi-outlet Xeri-Bug, 32, 52 —N— Non-base plants, irrigating, 51 —O— Outlet, 32 —P— Perman
® For Technical Assistance, Call Toll Free 1-800-247-3782 An ancient Indian legend tells of a terrible drought that befell the land hundreds of years ago. Crops withered and the watering holes dried up. For a generation there was no relief. Everyone but the children gave up hope. Then, one day, a great bird overheard the children’s simple, urgent prayers. The bird flew to the heavens and returned with the long-awaited, life-giving rain.
