Sub Surface Lawn Irrigation Using Netafim Drip Line

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Sub Surface Lawn Irrigation Basics

Drip Irrigation to most people is an efficient and effective method of watering plants and landscapes and Lawn Irrigation is usually applied using Sprinkler Systems.  It may come as a surprise that the same principals and benefits of Drip Irrigation can be applied to Lawn (Turf) Irrigation using Sub-Surface Drip Irrigation.  

Advantages of Sub-Surface Drip Irrigation:

  • Strong root development.
  • Even Distribution of Water throughout the watering area with evenly spaced emitters.
  • No evaporation or run off of water.
  • Silent and Invisible operation.
  • Up to 70% more efficient than traditional turf watering methods for cost effective operation
  • Inexpensive and easy installation (water needs and design layout can be done with little to no experience).
  • Can be installed to a basic hose faucet (no need for connecting directly to water lines)

Below is an illustration of a typical Sub-Surface Drip Irrigation Installation using Netafim Techline CV Drip Line followed by a summary of design techniques and system components required for a typical system.  These general guidelines can be used for virtually any sub-surface turf system and should give you all you need for a successful installation.

Please note: When installing a sub-surface drip system for new turf some overhead traditional watering is needed to establish initial root growth before the sub surface system becomes effective.

Sub Surface Drip Line for Lawn Irrigation

System Components

As the image above illustrates Sub-Surface Turf Systems are basically comprised of 4 system components;

  • Water Source Connection – This is often referred to as a Drip Zone Source Connection and is usually comprised of a valve, filter, and pressure regulator.  For Sub-Surface systems the pressure and flow rate is often low enough to replace the valve with a simple hose end timer.
  • Supply and Exhaust Headers – The supply line can be either PVC or Poly Tubing but for our illustrations we will assume Poly Tubing for easy installation.  These lines are the distribution lines for the Drip Line and the size of the Header is dependent upon both the water required and the water available (this is explained in more detail below).  The connection from the Header to the Drip Line can be accomplished with several combinations of fittings but the easiest method is to use Quick Tap Saddles to eliminate the need for cutting Header line and to greatly reduce installation time.
  • Netafim Drip Line – We recommend using Netafim Techline  Drip Line (often referred to as soaker hose).  This isn’t the soaker hose you used to purchase at the local hardware store, but rather the Iron Man of soaker hose drip line.  Techline is one of the most technologically advanced drip lines on the market today with pressure compensating, self flushing emitters built into the line with additional features such as root barrier technology and the elimination of the need for an air release valve.
  • Manual Flush Valve – All Subsurface Irrigation Systems must have a flush valve that is typically located at the furthest point from the water source and more favorably at the lowest vertical point of the system for easier drainage.  The system should be flushed once or twice a year by simply opening the manual valve (usually housed in a simple 6″ round valve box) and running water through the system to clear debris.  The valve is also used at the end of the season to drain the system which can often be accomplished with a shop vacuum with small to medium sub-surface systems.

We will illustrate in more detail common system components later in this tutorial, but first must address planning consideration for your system to ensure superior watering results.  The planning is simple but necessary and includes the determination of soil type and the appropriate Netafim Techline CV , the size of the watering area, and choosing the appropriate drip line and header size.

Sub Surface Turf Irrigation – Drip Line Basics

Choosing Your Drip Line – Sizing Spacing and Flow Rate

Sizing your Netafim Techline for your sub-surface system is your first stop in the planning process and often has an impact on other factors such as Header Sizing and Zoning depending on the size of the system and water requirements.

The first step in planning your Drip Line requirements is to have an understanding of what type of soil you are dealing with.  For simplicity we have broken this down into two main categories as shown below.  The soil type effects the rate of absorption and dissipation from the emitters and therefore has an impact on the row spacing of your drip lines and the rate of flow from each emitter.  The chart below provides a guideline for which Drip Line is right for your situation.

 

Flow Rate Per 100 ft of Drip Emitter Tubing

The flow rates outlined above can determine what size of lateral distribution line will be required for your sub surface drip irrigation system.  As we have illustrated in the tubing flow rate tutorial.

Maximum Lateral Run Length

As you can see from the above chart, PSI will affect the maximum lateral run length for your system.

We will now walk through an example utilizing what we know about the Drip Line characteristics and applying the basics for Drip Line planning.

Planning Your Drip Line Layout

Planning a Sub Surface Turf Irrigation System is not much different from planning any Drip Irrigation System.  The basic planning is the same and necessary to get the most out of your system.

Step 1: Put It On Paper!: You don’t have to be an artist for this part but some graph paper will usually help you out.  Draw out the turf area with as much general detail as possible with regards to distances, structures, and water source location.  The following is a critical list of information for your system:

  • Water Source and Distance from Water Source to the start of the Drip System
  • Number of Rows and Length of Rows (to calculate total drip line required).
  • Distance Between Rows (assume 12″)
  • Number fo Emitters and Total Water Requirements

This is the basic information needed to get started.

Water Source

As with all Drip Irrigation Systems one of the most important components of information needed is your Water Source capacity and pressure.  The amount of water and pressure you have available is critical to the design of the sub surface system   The flow rate and pressure available will help to determine how many rows you can water at any one time and how many zones you may require.  The following information will assume an existing water supply with set or municipal pressure.

Flow Rate: The easiest and most tried and true method for measuring your flow rate is the 5 gallon bucket method.  Simply fill a 5 gallon (19 Litre) bucket with your outdoor faucet or water outlet and record the time it takes to fill.  You can then calculate the flow rate based on your results.  The following is an example.

Example 1: 45 Seconds to Fill: To Calculate the flow rate you divide 60 Seconds by 45 Seconds and Multiply by 5.

Flow Rate = 60 / 45 x 5 = 6.67 Gallons Per Minute or 400 Gallons Per Hour ( 60 Minutes x 6.67 Gallons Per Minute )

Example 2: 90 Seconds To Fill:

Flow Rate = 60 / 90 x 5 = 3.33 Gallons Per Minute (GPM) or 200 Gallons Per Hour (GPH)

Pressure: Calculating pressure requires the use of a pressure gauge or an approximation of municipal pressure.  If using a pump, you may be able to dictate pressure precisely.  Pressure decrease over distance travelled in all tubing materials and the decrease increases as the size of your tubing decreases.  In addition to the static pressure loss there may also be dynamic pressure loss which is the pressure lost from emitter output down the drip line.  Below is a basic chart of pressure loss for both Poly and PVC tubing.

Poly TubingMax. Flow GPM (GPH)PSI Loss/100ftSch 40 PVCMax. Flow GPM (GPH)PSI Loss/100ft
1/2″4.6 (276)8.81/2″4.6 (276)7.7
3/4″8.2 (492)6.33/4″8.2 (492)5.6
1″13.4 (804)4.81″13.4 (804)4.2
1 1/4″23 (1380)3.11 1/4″23 (1380)3.1
1 1/2″33.8 (2028)2.91 1/2″33.8 (2028)2.9
2″52.3 (3138)1.92″52.3 (3138)1.9

As most Drip Emitters and Drip Emitter Tubing operate between 10 to 60 psi there is usually a wide range to work with but pressure loss must be considered, especially if travelling a long distance between the water source and the start of your Sub Surface Drip Irrigation System. The general rule of thumb is to start bigger to avoid pressure loss issues.

You are now ready to apply this information to your Sub Surface Watering System.

Drip Zone Planning For Sub Surface Drip Irrigation Systems

Now that we have gone over the basics for Drip Emitter Tubing and Flow rates we will apply this to a sample sub surface drip system.  For this example we will assume the following:

  • 240 gph flow rate available
  • 50 psi
  • We will use Techline DL with a .42 gph emitter output rate and 12″ spacing between emitter.

The illustration below will serve as our sample property for the installation of the sub surface system.

We will now illustrate our Drip Line layout ove our property sketch to calculate our Drip Line requirements and Water Requirements for the system.

Drip Line Calculation:

3 x 36   = 108

16 x 30 = 480

5 x 18   = 90

Total     = 678 ft

Water Requirement:

Since our Drip Emitter Tubing is spaced at 12″ we will have 678 emitters each with an output of .42 gph so our water requirement for the entire yard is calculated as follows:

678 Emitters  x .42 GPH/Emitter = 271.2 GPH

At this point we can see that if we are using a .42 gph emitter flow rate we will not be able to water the entire system at one time and will need to split the sytem into two zones as our water available is 240 gph and we need 271.  That being said we always recommend to be conservative with water estimates and never plan for more than 75% of water available, which would make our available flow 203.4 gph (271.2 x 75%).

Planning Alternatives

As we noted above our sample system will need to be split into 2 zones, however depending on the the variables you are presented with the same layout two zones can be avoided.

Drip Emitter Output: If we were to reduce the emitter output to .26 gph the water requirement for the system would then be 176 gph (678 emitters x .26 gph/emitter).

Flow Rate Available: If our flow rate availabe had been 400 gph we also could have avoided the need for two zones.  However we must also keep in mind that this would require the use of a 3/4″ supply header to the system as a 1/2″ poly tube has a maximum flow rate of 240 gph.

We will now continue with our 2 zone assumption to illustrate the system, however the connections and layout are virtually identical to that of a one zone system if our assumptions had changed.

Component Assembly For Sub Surface Drip Irrigation Systems

We will now put together our sample sub surface drip system using 2 zones.  As we previously discussed each zone will have the following components which we will examine seperately:

  • Water Source Connectione
  • Air Release Vent
  • Supply Header and Drip Line Connections
  • Exhaust Header
  • Zone Drainage

Water Source Connection

The Water Source Connection commonly consists of the following components:

  • Back Flow Prevention Component
  • Manual or Automated Valve for turning the system on and off
  • Screen or Disk Filter
  • Pressure Regulator

For this discussion we will assume that all systems will be initially connected to a standard hose thread faucet with a 3/4″ Male Hose Thread Conneciton. See illustrations below.

Back Flow Prevention: Back Flow Prevention is often mandatory in certain municipalities.  If you are using a Hose End Timer (below) as your on/off valve the back flow prevention (DD-HVB) will be connected after the timer.  If you are using solenoids the back flow prevention is usually placed before the solenoids. For Back Flow Components for Solenoid Systems please click here.

Manual and Automated System Controllers: When designing a drip irrigation system (or sprinkler system) a decision will likely be made for manual or automated on/off control.  This often is a matter of preference and can be implemented in a few different ways:

  • Manual Control – This can be as simple as turning on the tap, but can also take the form of a flow control valve further down the line.  This is obviously the most economical method but you must be present to operate the system which obviously lacks the convenience of an automated watering system
  • Hose End Timers – This is a simple solution for systems running off of a standard hose bib (faucet).  Hose End Timers come in single, double, and four zone models and are easy to program and now available with WIFI control.
  • Battery Operated Solenoid Controllers – DC Stand Alone Controllers are commercial grade and an excellent choice when the connection to the system is down line or zones are located in different areas.  Additional zones can be added anywhere.
  • AC Controllers and Solenoids – AC Controllers and Solenoids are the choice for both large and small systems.  Controllers are mounted indoors or outdoors and hard wired to inidividual solenoid valves.  Perfect for multi zone layouts, and allows for the addition of future zones.

Screen and Disk Filters: Filtration is a critical component of any drip irrigation system and an important component to ensure the long term operation of any drip watering system.  The two most common filtration choices are Screen and Disk Filters, which are available in a variety of thread sizes for both big and small drip sytems.

Screen vs Disk Filters

Screen Filters: Screen Filters are the most commonly used filters and in most cases the most economical.  They are a good choice for removing hard particulates like sand and dirt but not the best choice for removing organic material such as algae and slime.  These materials will clog a filter and are hard to remove in the cleaning process.  Screen Filters are a great choice for systems using pre-filtered municipal water or water free of organic material.  Screen Filters are available in both Pipe Thread (for Solenoid Systems) and Hose Thread (for Hose End Timers).

Disk Filters: Disk Filters are an excellent choice for removing both hard particulate and organic materials.  Disk Filters house a stack of hundreds of round disks which are housed in the filter cartridge.  When water is passed over the disks, particulates are trapped in the tiney grooves of the disk as water is forced through the filter.  Disk Filters are easy to clean by simply removing the disk stack and spraying down the individual disks.  Disk Filters come in a variety of thread sizes and are only available for Pipe Thread fittings (hose thread adapters are available).

Pressure Regulatators: Drip Irrigation Systems usually operate between 6 and 60 psi depending on the type of drip system you are installing.  As most municipal pressure is either at the higher end of this range or exceeding this pressure, a pressure regulator is usually necessary for all drip systems.  Presssure Regulators are offered in both Pipe and Hose Thread configurations.

Water Source Connection Illustrations

1. Water Source Connection With Hose End Timer

Parts List From Left To Right
Hose End Water TimerWater Timers are offered in Single, Double, and Quad zone models.  Shown here with the DIG B09D Digital Water Timer
Hose Vacuum BreakerHose Vacuum Breaker DD-HVB  prevents water from re-entering the water system.
Hose Thread FilterHose Thread Screen Filters are most commonly installed with Hose End Timers.  Shown above DD-YSHFM
Pressure RegulatorPressure Regulator to reduce and equalize pressure from water source.  Shown with DD-HPR25HQ 25 PSI Regulator
Line ConnectionInstalled after the Pressure Regulator their are several choices for connections to distribution lines.  Shown above with the DL-FHS600 for 1/2 Solid Tubing.  If using 3/4″ tubing the fitting would be DD-CHS940

2. Water Source Connection With Battery Operated AC Controller and Solenoid

Parts List From Left To Right
Hose Thread Adapter(Optional) This component will enable you to switch from Hose Thread to Pipe Thread Fittings.  All Solenoid Valves are Pipe thread so it is often recommended to adapt for a better connection.
Adapter Bushing(Optional) Many Solenoid Valves are 1″ FPT, if not using a 3/4″ Solenoid this component adapts a 3/4″ water source to a 1″ valve.  If you use a 3/4″ Solenoid Valve this component is not required.  Part Number 439-131
AC Controller The DC Timer and Solenoid Valve can be sold seperately or as a package. as shown with the DIG710AP.  AC Controllers come in 1, 4, and 6 zone models.
Solenoid ValveThe Solenoid Valve is operated from the AC Controller and is available in 3/4″, 1, 1.5″ and 2″ sizes.  When using AC Controllers a Latching Solenoid must be used.
Adapter Bushing(Optional) Many Solenoid Valves are 1″ FPT, if not using a 3/4″ Solenoid this component adapts a 3/4″ water source to a 1″ valve.  If you use a 3/4″ Solenoid Valve this component is not required.  Part Number 439-131
Pipe Thread FilterFilters used with Solenoid Valves should be Pipe Tread (MPT) Filters.  Pipe Thread Filters are available in 3/4″, 1″, 1.5″, and 2″ sizes.  Shown here with the Netafim DF075-140 Filter
 Pressure RegulatorAs with the Filter if using Pipe Thread (MPT) components, it’s advised to use a Pipe Thread Pressure Regulator.  Shown with the Netafim NET35PR
Line ConnectionThere are many options for Pipe Thread Line Connections.  Shown here with the DD-CFP700, a DD-CFP940 would be used for 3/4″ Tubing.  Other options include Insert Female Adapters for larger line connections

3. Water Source Connection with an AC Controller and Solenoid Valves

Parts List From Left To Right
Irrigation ControllerAC Controllers are available in a wide range of zone sizes and allow for easy expansion for additional zones.  Irrigation Wire Is used to connect to Solenoid Valves.  Shown with Rain Bird ESP-TM2 Controller.
Hose Thread Adapter(Optional) This component will enable you to switch from Hose Thread to Pipe Thread Fittings.  All Solenoid Valves are Pipe thread so it is often recommended to adapt for a better connection.
Solenoid ValveThe Solenoid Valve is operated from the AC Controller and is available in 3/4″, 1, 1.5″ and 2″ sizes.  When using AC Controllers a Latching Solenoid must be used. Shown with the Rain Bird DV075 Solenoid Valve
Pipe Thread FilterFilters used with Solenoid Valves should be Pipe Tread (MPT) Filters.  Pipe Thread Filters are available in 3/4″, 1″, 1.5″, and 2″ sizes.  Shown here with the Netafim DF075-140 Filter
 Pressure RegulatorAs with the Filter if using Pipe Thread (MPT) components, it’s advised to use a Pipe Thread Pressure Regulator.  Shown with the Netafim NET35PR
Line ConnectionThere are many options for Pipe Thread Line Connections.  Shown here with the DD-CFP700, a DD-CFP940 would be used for 3/4″ Tubing.  Other options include Insert Female Adapters for larger line connections

 

Component Assembly For Sub Surface Drip Irrigation Systems

Continuing with our Drip Zone Assembly we will now look at the components required for assembling an Air Release Valve for a Sub-Surface Drip Irrigation System:

  • Water Source Connection
  • Air Release Valve
  • Supply Header and Drip Line Connections
  • Exhaust Header
  • Zone Drainage

Air Release Valve Assembly

The Air Release Valve is often overlooked but is a valuable component for maintaining a worry free sub-surface drip irrigation system.  The air release valve allows air to escape the system on it’s initial start up until the system is full of water.  Once full the valve automatically closes until the cycle is finished and then allows air to flow back into the system.  The air release valve helps in avoiding clogging of emitters due to back suction and will extend the long term life of the system.   It also helps to avoid water hammer at the start of a watering cycle.

Where to Install an Air Release Valve

The Air Release Valve should be installed at the highest point for each drip zone.

Connecting an Air Release Valve

There are several ways to connect an Air Release Valve to an Irrigation supply line depending on what size of line you use.  We will now provide several examples using a variety of components, all of which work on the same principle.  We will look at connecting at 1/2 and 3/4″ and larger distribution lines separately.

Connecting an Air Relief Valve to a 1/2″ Distribution Line
Since all Air Relief Valves have male pipe thread all connection options must have a female pipe thread fitting for a proper connection.
Option 1

** When using insert fittings using a gear or crimp clamp is recommended

Connecting an Air Relief Valve to a 3/4″ and 1″ Distribution Lines
Since all Air Relief Valves have male pipe thread all connection options must have a female pipe thread fitting for a proper connection.
Option 1Option 2Option 3
3/4″ Poly

3/4″ Blu Lock

3/4″ Poly

1″ Poly

1″ Poly

1″ Poly

Component Assembly For Sub Surface Drip Irrigation Systems

Continuing with our Drip Zone Assembly we will now look at the components required for assembling the Supply and Exhaust Headers and the Drip Lines connecting the two.

  • Water Source Connectione
  • Air Release Valve
  • Supply Header and Drip Line Connections
  • Exhaust Header
  • Zone Drainage

Supply and Exhaust Header Connection Assemblies.

Please Note:  The assemblies illustrated in this tutorial are for the actual drip line assemblies to the header and exhaust assemblies.  When connecting to your supply header to your main distribution line you may also need elbow and tee connections to navigate to the drip lines.  This configuration will be dictated by the layout of your property and are usually very simple to figure out.

Basics For Drip Line Installation  For Sub-Surface Drip Systems

Emitter Installation Pattern and Spacing:  It is recommended to install drip line emitters in a staggered pattern to provide better coverage (see illustration below).  For spacing we recommend lines to be spaced 12″ apart with 12″ emitter spacing for good coverage.

Installation Depth:  We recommend installing sub surface Drip Lines at a 4″ depth.  This depth encourages root growth while also being deep enough to avoid being damaged by aeration equipment.

Component Installation Options: As with other component illustrations there are several ways to install drip lines in a sub-surface turf irrigation installation.  We will now provide several examples using a variety of components, all of which work on the same principle.  We will look at connecting at 1/2 and 3/4″ and larger distribution lines seperately.  As you can see from the illustration below we have also distinguished parts for either 12mm Techline EZ or 17mm Techline.

Connecting Drip Lines to a 1/2″ Distribution Line – Mid Lateral Connection
Since all Male Adapters have male pipe thread all connection options must have a female pipe thread fitting for a proper connection.
Option 1Option 2Option 3
Connecting Drip Lines to a 1/2″ Distribution Line – End of Line
Option 1Option 2

** When using insert fittings using a gear or crimp clamp is recommended

Connecting Drip Lines to 3/4″ and 1″ Distribution Lines
Since all male adaptors have male pipe thread all connection options must have a female pipe thread fitting for a proper connection.
Option 1Option 2Option 3
3/4″ Poly

3/4″ Blu Lock

3/4″ Poly

1″ Poly

1″ Poly

1″ Poly

Connecting Drip Lines to a 1/2″ Distribution Line – End of Line
Option 1Option 2

Additional Methods: In addition to the connection assemblies illustraed above it is also possible to connect the drip lines using 12mm Techline EZ or 17 mm Techline as your Supply and Exhaust headers using standard 12mm and 17mm Tee and Elbow Fittings found in the Techline Fittings Category. 

We will now look at completing the Sub Surface Drip Zone with a drainage valve.

Component Assembly For Sub Surface Drip Irrigation Systems

Continuing with our Drip Zone Assembly we will now look at the components required for the Drainage Valve.

  • Water Source Connectione
  • Air Release Valve
  • Supply Header and Drip Line Connections
  • Exhaust Header
  • Zone Drainage

Zone Drainage Installation and Assembly

Sub Surface Drip Irrigation zones need to be drained for winterization and periodic flushing of the line to ensure worry free operation, depending on the quality of water being used and proper filtration.

Location: Zone Drainage should be located at the lowest point of the Drip Zone and can be housed in a small valve box (optional).  The zone drain valve is to simply turn on manually and the most of the water will likely flow out naturally.  For winterization, depending on the size of the zone and system, nothing more than a shop vac will be needed to completely drain the lines.  If using a small valve box to house the zone drainage it is often recommended to put a small bedding of gravel at the base of the box for a tidy area and to avoid clogging with mud.

Zone Drainage Installation Component Options

It is relatively simple to install zone drainage, with the only variable being the size of tubing used to go from the exhaust header to the zone drain.  The drain line will either be a piece of tubing used for the Headers or a small piece of Drip Line.  We have illustrated a few option below.

Tubing SizePhotoConnection
12mm Techline EZT12SOV Connects Directly to 12mm Techline EZ
17mm TechlineTLSOV Connect Directly to 17mm Techline
1/2″ 700 Series TubingDL-FCV600 Direct Lock Fits directly to 700 series tubing
3/4″ 940 Series TubingDD-FCV940 Connect Directly to 940 series solid drip tubing.
3/4″ and 1″ Irrigation Poly1436-007 (3/4″) and 1436-010 (1″) are combined with 0921-07 (3/4″ FPT Ball Valve) or 0921-10 (1″ FPT Ball Valve)
6″ Round Valve BoxNDS -06R 6″ Round Valve Box

This concludes our tutorial for sub surface turf irrigation using drip emitter tubing.

irrigationdirectSub Surface Lawn Irrigation Using Netafim Drip Line

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