Drip Irrigation Selection

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• Intro/TOC
• Water Use Facts
• Drip Irrigation Defined
• History of Drip
• Drip System Components
• Typical Drip Applications
• Factors to Consider
• Types of Drip
• Point Source Applications
• Inline Applications
• Keys & Specs
• Resources & Contact Info

0:00 – 3:31: Intro/TOC

Overview of Shelly and GPH (2:00)

3:32 – 4:34: Water Use Facts

Water and the population (3:32)

• According to the Census Bureau decennial census, the U.S. population is growing by approximately 3.3 million per year.
• The average American uses 100 to 175 gallons of water per day.
• That’s 63,875 gallons per year.
• The Environmental Protection Agency says drip irrigation systems can save ups to 30,000 gallons of water per year, which is about three times what the average landscape consumes.

4:35 – 5:03: Drip Irrigation Defined

• The slow, precise application of water directly to the soil at the root zone of the landscape plant
• Drip provides an optimal amount of water directly to plant roots, maintaining an optimal degree of soil moisture to meet the plant’s evapotranspiration needs.

5:04 – 7:36: History of Drip

• 100 BCE: Ancient China: porous unglazed pots, water seeped through clay – called olas
• 1800s: Porous clay pipe – Middle East
• 1920s: Germans invented perforated pipe
• 1950s: Plastic extrusion and molding
• 1960s: U.S. farmers began to use drip irrigation for crops
• 1980s: Introduced to commercial landscape in U.S.
• 1990s: Pushback in landscape industry
• 2000s: Resurgence, water shortages, more efficient, more education

7:37 – 12:10: Drip System Components

• Backflow preventer to prevent soil, salmonella, bacteria, etc. from being sucked back into the system
• Controller
• Isolation and control valves to control the flow of water
• Pressure regulator to reduce water pressure and keep it at a constant level
• Filter to clean the water and remove grains of sand, etc.
• Drip tubing that is laid on the ground between plants
• Emitters attached to the drip tubing to regulate how fast the water is released to the soil
• Flush end cap or indicator flush nozzle

Drip zones (9:56):

• Above grade
• In a valve box

Diagram of a drip system (11:37)

12:11 – 13:29: Typical Drip Applications

• Streetscape
• Slopes
• Interior scapes
• Malls, hospitals, casinos, airports, hotels
• Severe environments
• High wind, evaporation

13:30 – 24:37: Factors to Consider

• Client parameters

Special requests or what they envision

• Project type
• Commercial or residential
• New or existing
• Use what you have, or need additional or upgraded equipment

Other important factors to consider (14:38):

• Plant spacing and selection
• Land layout
• Climate and weather
• Soil type
• Water quality

Plant selection (14:48)

The plants’ water requirements are the most important factor.

• Local law or ordinance
• Color or seasonal, high maintenance
• Durability and low maintenance
• Does the plant you select do well in the region of your project?

Plant watering guide

General guidelines (17:00):

• The roots of turf/grasses grow about 1 foot deep.
• Small shrubs and other plants reach 1 to 2 feet deep.
• Taproots of some trees and shrubs may grow more deeply into the soil. Most roots tend to concentrate in the top 2 to 3 feet.
• Watering below the root zone only wastes water.

Plant spacing (17:40):

• Sparse
• Potted grouped
• Dense

Land layout (19:04)

• What is your elevation across the project?
• Do you have a slope?
• Water pressure loss or gain?
• Easily accessible or not?

We lose pressure when moving up. We gain pressure when moving down.

Climate/Weather (20:05)

• High wind
• No wind
• Dry or humid
• Season change and impact
• Climate history and weather trends

Soil type (20:25)

Water infiltration in soil types (20:50):

• Sandy soil
• Water for a longer period of time. Imagine filling a column of water.
• 1 inch of water penetrates about 123 inches.
• Loam soil
• Moderate watering according to the plants’ needs.
• 1 inch of water reaches 7 inches in depth.
• Clay soil
• Water less time: cycle and soak.
• 1 inch of water soaks only 4 to 5 inches in depth.

Other soil considerations (21:50)

• Site analysis of project
• Or retrieve reports from the client or on your own.
• The soils can vary throughout the project.
• Soil amendments may be necessary.

Water quality (22:10)

• Water source
• Domestic, potable and non-potable, reclaimed, well
• Testing
• Send to lab, testing services (you can even test it yourself if not required), hardness of the water (salt or calcium)
• Documenting
• Important if issues arise later

What to look out for when testing water (24:00):

• High mineral content
• The top 2 culprits are:
• Calcium
• Magnesium
• Filtration and/or chemical treatment

24:38 – 29:36: Types of Drip

Inline (24:38)

• Emitters are inserted into the tubing (polyethylene) spaced every 12 or 18 inches.
• Used with fittings, compression, swivel lock, or barbed.
• The tubing has a plastic look and texture and is aka PE.
• Some emitters have a check valves that hold back up to 10 feet of elevation change.
• Toro uses Treflan and Rainbird uses CopperShield to help slow root intrusion.

Point source (26:10)

• Point source is a combination of emitters and tubing used together.
• Different types of emitters: single-outlet, multi-outlet, threaded, barbed, micro-spray, and micro-stream.
• Certain emitters in point source have check valves up to 15 feet of elevation change.
• Typically combined with hose, tubing, and rigid PVC or PE pipe, with fittings compression, swivel lock, insert, micro-tubing, and micro-fittings.
• Rule of thumb: When the distance between plants is greater than 3 feet on center, use point source.

Inline tubing and components (27:04):

• Typical size used in landscape is 17 mm.
• 12-inch spacing at .6 gph or .9 gah – also, 18-inch spacing is available.
• Used with compression, lock, and barbed fittings.

Point source components (27:34):

• Single-outlet, multi-outlet, barbed, or threaded.
• Multi-outlet barbed or threaded.
• Streamers and micro-sprays and bubblers.

Supply tubing for point source (28:40):

Polyethylene (PE)

• Compatible with compression fittings lock fittings, and insert fittings.
• Usually dealing with 700 x 600 supply, available in micro- or spaghetti tubing.
• Plastic texture, more economical.
• Life: 7 years in UV

Poly vinyl chloride (PVC flex or vinyl)

• Compatible with PVC SCH fittings with solvent weld.
• Usually working with 1/2-inch IPS size, available in micro- or spaghetti tubing.
• More of a rubber texture, more expensive.
• Life 30+ years in UV.

29:37 – 33:12: Point Source Applications

Point source on-grade (29:37):

• Barbed, single-outlet emitters
• Threaded single-outlet emitters

Point source below grade (32:02):

• Threaded emitters
• Rigid PVC schedule 40 pipe layout to a PVC flex riser.
• Bury everything but the emitter.
• Reclaimed color coding.
• Camouflage to blend in with the landscape.

Point source commercial containers (32:55)

33:13 – 35:35: Inline Applications

Inline on-grade (33:13)

Inline below grade (34:36)

35:36 – 39:04: Keys & Specs

Complete the system (35:36)

• Take advantage of available accessories.
• Stakes, indicators, flushes, air relief valves, fittings.

Keys to success (35:53):

• Design with hydrozones.
• Definition: Hydrozoning is the practice of clustering together plants with similar water requirements in an effort to conserve water.
• Know your hydraulics and maintain at least 10 PSI at the last emitter.
• Choose the highest-quality product available for your application.

Study manufacturer specs (37:27):

• Understanding the unique characteristics of each manufacturer’s product that you’re using in your project.
• Example: Operating pressure, threads, fittings, compatibility

Install drip yourself (38:10)

• Ideas are unlimited.
• Trial and error.
• If you have experience installing, it will make the designing of drip that much more relatable, able to communicate with the installer at a different level.
• Most manufacturers’ ideas have come from the irrigation designer or installers.

39:05 – end: Resources & Contact Info

Commercial irrigation resources (39:05):

• WaterSmart Checkup
• Irrigation Association
• United States Golf Association Water Resource Center
• Landscape Irrigation Best Management Practices
• Water Conserving Tips for HOAs and Large Commercial Properties
• Water Use It Wisely
• A Landscaping Guide for Homeowners Associations
• Turf and Landscape Irrigation Best Management Practices
• Best Management Practices for Commercial and Institutional Facilities (EPA)
• CIMIS Urban Resource Book

Shelly Walker contact information:

GPH Irrigation Products

8031 Redwood Ave., Fontana, CA 92336

Phone: +1 866-582-9684

email: This email address is being protected from spambots. You need JavaScript enabled to view it.

website: gphirrigation.com

How a check valve works (39:50)

How to determine when to make inline or point source above or below ground (41:25)

What to do differently with reclaimed water (42:20)

Run-through of the Water Use It Wisely plant watering guide linked above (43:30)

Question: Does a 1-GPM emitter tend to clog more easily than a 4-GPH emitter?

Answer: Not at all. However, a 1-GPM bubbler will clog more easily than a 4-GPM bubbler.