Irrigation Design

1. Irrigation Design What is it?What is it?

2. Irrigation Design

3. Goals Planning Landscape Watering Zones Irrigating Low Water Landscapes Methods for watering plants Components of a irrigation system Design Installation Maintenance Before we actually jump right into irrigation design we are going to review some of the things that are related to the design process. Before we actually jump right into irrigation design we are going to review some of the things that are related to the design process.

4. Planning Landscape Water Zones Climate information Site microhabitats Modifying habitats By adding irrigation Modifying topography Slope ,drainage or adding soil The plan for watering zones that you develop needs to incorporate basic climate information, existing microhabitat differences on the site. Things like: Neighbor trees shading an area, boggy area modifying the site irrigation or water-harvesting to create habitat for plants from wetter places modifying topography (slope and drainage) or soil to accommodate plants from drier places. These sorts of thing will greatly influence the final irrigation design as well as the planting designThe plan for watering zones that you develop needs to incorporate basic climate information, existing microhabitat differences on the site. Things like: Neighbor trees shading an area, boggy area modifying the site irrigation or water-harvesting to create habitat for plants from wetter places modifying topography (slope and drainage) or soil to accommodate plants from drier places. These sorts of thing will greatly influence the final irrigation design as well as the planting design

5. Watering Zones and Plant Selection Water requirements four categories: minimal water (10 inches or less), low water (10-15 inches), medium water (15-20 inches), and high water (over 20 inches) Precipitation zone Four zones:Desert, semi-desert ,foothill, and mountain plant communities A fundamental principle of native plant landscaping, and of waterwise landscaping in general, is to group plants with similar water requirements We can break down water requirements for native plants into four categories These categories correspond to the precipitation zones for desert, semi-desert, foothill, and mountain plant communities. A fundamental principle of native plant landscaping, and of waterwise landscaping in general, is to group plants with similar water requirements We can break down water requirements for native plants into four categories These categories correspond to the precipitation zones for desert, semi-desert, foothill, and mountain plant communities.

6. Landscape Plan Watering zones Plant communities Plant communities = water zones Determines type of system Number of irrigation valves Watering zones will directly influence our landscape plan these communities will essentially become our water zones, Foothill Trees and understory will require the same water requirement Drip Inline Microsprays Grass even though it id semi-desert Small sprays or rotor (size and shape) Semi desert Drip or maybe no system at all Desert No supplemental irrigationWatering zones will directly influence our landscape plan these communities will essentially become our water zones, Foothill Trees and understory will require the same water requirement Drip Inline Microsprays Grass even though it id semi-desert Small sprays or rotor (size and shape) Semi desert Drip or maybe no system at all Desert No supplemental irrigation

7. Water Requirement Determine water requirement natural precipitation + supplemental water = water requirement of plant “Top up” to the maximum of the precipitation zone to keep the plant looking it’s best The idea is to ‘top up’ the water that is provided as natural precipitation with enough inches of supplemental water to reach a total that approximates the water requirement of the plant.The idea is to ‘top up’ the water that is provided as natural precipitation with enough inches of supplemental water to reach a total that approximates the water requirement of the plant.

8. Things to Remember Precipitation rate vary from year to year Wild plants adapt Ballpark approach Focus native plants vary widely in their water needs natural precipitation does count there is definitely such a thing as too much water precipitation varies dramatically from year to year in any given spot wild plants for the most part have no trouble coping with this variation. This means that you just have to get in the ballpark in your watering zone planning, not accurate down to the last inch. You need to focus on three things—first, native plants vary widely in their water needs depending on what precipitation zone they come from. Second, the water that falls out of the sky as natural precipitation does count toward meeting those water needs. You only have to make up the difference. And third, there is definitely such a thing as too much water. precipitation varies dramatically from year to year in any given spot wild plants for the most part have no trouble coping with this variation. This means that you just have to get in the ballpark in your watering zone planning, not accurate down to the last inch. You need to focus on three things—first, native plants vary widely in their water needs depending on what precipitation zone they come from. Second, the water that falls out of the sky as natural precipitation does count toward meeting those water needs. You only have to make up the difference. And third, there is definitely such a thing as too much water.

9. Irrigating Low Water Landscapes Overview; Considerations Irrigation of a low water landscape non-uniform “hourglass” plants Some water stress is OK Unlike turf irrigation, there are many ways of approaching irrigation of a low water landscape These landscapes are inherently non-uniform, so uniform application is not always necessary` Using “hourglass” plants; better exploit soil water with more space, Mild-moderate water stress is OK if appearance is not affected; moderate water stress most OK in established shrubs/perennials mild water stress least OK in newly transplanted trees ` Unlike turf irrigation, there are many ways of approaching irrigation of a low water landscape These landscapes are inherently non-uniform, so uniform application is not always necessary` Using “hourglass” plants; better exploit soil water with more space, Mild-moderate water stress is OK if appearance is not affected; moderate water stress most OK in established shrubs/perennials mild water stress least OK in newly transplanted trees `

10. Irrigating Low Water Landscapes Overview Water use in non-uniform low water landscape different than turf Evapotranspiration (ETo): Estimation of plant water use from climatic factors, radiation, wind, air temperature, humidity and some implicit or assumed plant factors that are combined into a number that approximates how much water is lost from a hypothetical cool season turf=reference evapotranspiration=ETo ETo is used in irrigation scheduling, the basis of proper irrigation management—when and how much—for both drip and sprinkler ETo, the amount of water transpired and evaporated from a surface, is an approximate measure of how much water is needed Link, Link2

11. Irrigating Low Water Landscapes: Design Hand irrigation - permanent versus temporary (for subsequent non-irrigated landscape) The lower the irrigation use, the more critical plant selection becomes Sprinkler irrigation versus low volume/drip irrigation? Sprinkler best suited for low growing, uniform surface plantings such as ground cover, low perennials/shrub Low volume/drip best for tall growing or widely spaced plants and small areas Irrigating low water landscapes several methods Hand irrigation is a viable alternative for the right personIrrigating low water landscapes several methods Hand irrigation is a viable alternative for the right person

12. Irrigating Low Water Landscapes: Design Advantages of low volume/drip irrigation Low pressure, 10-30 psi versus 30-60 psi for sprinklers Target application that does not need to wet entire root zone as trees can increase uptake in wetted zone and can utilize hydraulic transfer No loss due to overspray and wind, can easily irrigate oddly shaped areas

13. Advantages -Low Volume (cont) Does not wet entire area, discourage weed growth due to dry soil Fewer moving parts, lower pressure, less breakdown from water Above-ground flexible polyethylene tubing, sometimes below ground Targeted water application that only wets around the root zone Apply small amount of water for longer durations than sprinkler Because it does not wet the entire area, drip discourage’s weed growth due to dry soil Because it does not wet the entire area, drip discourage’s weed growth due to dry soil

14. Irrigating Low Water Landscapes: Design Disadvantages Potentially more costly and tedious to install, depending on size of area to be irrigated and plant density Potentially more maintenance/risk from breakage and damage from above-ground exposed parts Even when buried, easily damaged if there is frequent digging; don’t use under weed fabric Needs immaculately clean water; almost always requires installation of a filter

15. Components of a Drip Irrigation System VALVE- spigot, electronic valve, battery operated BACKFLOW, with culinary water you must have one PRESSURE Regulator, range of pressure for operation FILTER, a must with secondary water, smart person will use them with culinary as well, Logan city TUBE ADAPTER At this point we could have a DISTRIBUTION LINE (underground PVC OR POLYPIPE) OR WE COULD CONNECT DIRECTLY TO DRIP Tube (special thin walled polyethylene) EMITTERS punch directly into poly or connect to a SPAGETTI TUBE ,usually ¼ inch diameter End cap or looped DIFFER little from a sprinkler system which: Must have backflow protection Often need a pressure regulator (Logan pressure) Adapt to PVC or polypipe that goes out to the sprinkler headsVALVE- spigot, electronic valve, battery operated BACKFLOW, with culinary water you must have one PRESSURE Regulator, range of pressure for operation FILTER, a must with secondary water, smart person will use them with culinary as well, Logan city TUBE ADAPTER At this point we could have a DISTRIBUTION LINE (underground PVC OR POLYPIPE) OR WE COULD CONNECT DIRECTLY TO DRIP Tube (special thin walled polyethylene) EMITTERS punch directly into poly or connect to a SPAGETTI TUBE ,usually ¼ inch diameter End cap or looped DIFFER little from a sprinkler system which: Must have backflow protection Often need a pressure regulator (Logan pressure) Adapt to PVC or polypipe that goes out to the sprinkler heads

16. Design: Types of low volume/drip emitters Point Source Water comes from a single point; wets only area large enough to be covered with water through capillary action 0.5-2 gallons/hour; quality products are pressure compensating

17. Microsprinkler/sprays Water is sprayed out, covers an area 12-48”, either in a circle or half circle pattern, 1-10 gallons/hour Come in fixed output and adjustable output Adjustable output sprinklers easier to clean Types emitters (cont)

18. Types emitters (cont) Others Trickle tape: long, very thin plastic tubing with openings spaced 4”-12” apart, 5-10 gallons/100 ft; extremely thin tubing, easily punctured; tricky to use Porous tubing: ground-up rubber that emits water throughout entire circumference and length of tubing; useless

19. Design: Fittings Types Kind of like a tinker toy set Compression: slide tubing into fitting which has a sharp lip that snags the tubing Spin-loc: slide tubing over a nipple with an O-ring, then is tightened down with a twisting nut Barbed: slide tubing over a very barbed nipple that grabs the inside of the tubing Fittings are the hardware that connect the drip tubing together:tees, elbows, straight couplers, adaptersFittings are the hardware that connect the drip tubing together:tees, elbows, straight couplers, adapters

20. Design Fixed spacing design In-line emitters (trickle tape can be used the same way) Set at a regular spacing (1, 1.5, 2 feet) that are laid out parallel at distances also 1, 1.5, 2 apart

21. In-line, grid spacing drip system

22. Drip Design w/ In-line, Grid Spacing Advantages Easy to envision, engineer, and install prior to planting, very difficult after planting Looping piping results in even application rate Disadvantages Everything gets same amount of water, so some plants may get over watered if used in mixed planting Difficult to determine breaks if covered by vegetation staple it down,movement makes it resurfacestaple it down,movement makes it resurface

23. Drip Design w/ In-line, Grid Spacing Considerations Total output amount from all emitters <75% of the flow rate for the size of tubing If ¾” line supplies 12 gallons/minute (720 gal/hour) supportable output approximately 500 gallons/hour If 1 gal/hr emitters, spaced at 12” in-line, 12” between lines, then one valve can supply 500 ft2; if 18” square spacing using, then about 1000 ft2 covered If 0.6 gal/hr emitters, with 12”x12” spacing, 833 ft2; with 18”x18” spacing, 1800 ft2 can be covered Not full amount because of pressure losses

24. Drip Design w/ In-line, Grid Spacing Use fixed spacing drip when there is high plant density, such as perennial beds, or for large trees with a large root zone that needs to be watered Fixed spacing scheduling: treat it the same as a sprinkler system in terms of applying depth of water; two ways of scheduling irrigations: Irrigating at same interval, generally once/several days to once/several weeks, varying runtime according to conditions Irrigating at fixed runtime, varying interval between days (depletion method), based on amount of soil water available to the plant-rooting depth x amount of water in the root zone

25. Drip Design w/ Random Spacing Random spacing Snake tubing to individual plants and connect appropriate number of emitters Based on size of plant, scaled to all plants on the same irrigation zone

26. Drip Design w/ Random Spacing Best approach for wider-spaced plant material, particularly trees and shrub Suitable use for low volume sprinkler; adjustable flow low volumes sprinklers ideal, as they can be adjusted upwards at the plant grows Eg. Run 1-gallon/hour emitters to small shrubs, scale up with more emitters for larger plant sizes

27. Drip Design w/ Random Spacing Determine mature size then scale the number of emitters to that size based on size of other plants in that zone Example, mature bigtooth maple =10 feet canopy diameter, water use up to 18 gallons/day Use four adjustable low volume sprinklers to adequately cover root zone; for rabbitbrush with a two foot diameter, use one

28. Drip Design w/ Random Spacing Space emitter according to mature size so that a larger area of root zone is irrigated Overall Considerations In a sandy soil, irrigation frequency has to be increased for any type of system Assumptions for estimating plant water use are very coarse The more drought adapted the plant, the more leeway you have: if water runs short, plant very unlikely to die, will just grow slow Again, using low volume/drip irrigation requires very careful thought in designing