Landscape Irrigation Audit Guidelines

Okeechobee County Extension

Description

ƒƒ 1Landscape Irrigation Audit Guidelines Irrigation Water Management (IWM) is applying water according to crop needs in an amount that can be stored in the plant root zone. When to irrigate? • When soil moisture is depleted 30-50%, depending on time of year. How long to irrigate? • Time it takes to refill the root-zone. How much water should be applied? • Generally ¼” – ½” on turf grass, depending on depth of root-zone. How often to irrigate? • 1-2 times per week depending on time of year. (depending on age of planting) • According to long-term behavior of the irrigated turf. Available Water Capacity (AWC) is the portion of water in a soil that can be readily absorbed by plant roots of a crop. Soil moisture depletion is the amount of water required to raise the content of the crop root-zone to field capacity. Field capacity is the amount of water a well drained soil holds after free water has drained because of gravity. • For a coarse textured soil, drainage occurs soon after irrigation (or rain) because of relatively large pores and low soil particle surface tension. • In fine textured soil, drainage takes much longer because of smaller pores. • Major soil properties that affect field capacity are texture, structure, bulk density and strata within the profile that restrict water movement. • Generally fine textured soils can hold more water than course textured soil. • Soils with large amounts of organic matter hold water ...

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• Publié par: Shawyeg
• Nombre de lectures: 16
• Langue: English

Extrait

1 Landscape Irrigation Audit Guidelines Irrigation Water Management (IWM) is applying water according to crop needs in an amount that can be stored in the plant root zone. When to irrigate? •When soil moisture is depleted 3050%, depending on time of year. How long to irrigate? •Time it takes to refill the rootzone. How much water should be applied? •Generally ¼” – ½” on turf grass, depending on depth of rootzone. How often to irrigate? •12 times per week depending on time of year. (depending on age of planting) •According to longterm behavior of the irrigated turf. Available Water Capacity (AWC) is the portion of water in a soil that can be readily absorbed by plant roots of a crop. ƒSoil moisture depletionis the amount of water required to raise the content of the crop rootzone to field capacity. ƒField capacityis the amount of water a well drained soil holds afterfreewater has drained because of gravity. •For a coarse textured soil, drainage occurs soon after irrigation (or rain) because of relatively large pores and low soil particle surface tension. •In fine textured soil, drainage takes much longer because of smaller pores. •Major soil properties that affect field capacity are texture, structure, bulk density and strata within the profile that restrict water movement. •Generally fine textured soils can hold more water than course textured soil. •Soils with large amounts of organic matter hold water longer than sandy soils. •Compaction increases soil density, reduces pore space and decreases permeability. •Restrictive layers can restrict root development and water movement lower in the soil.

Example of Landscape Evaluation Overview,July, 2001 Observations •Unique landscapes in each lot •Typical irrigation systems •Some rotors on largerPopup sprinklers – ¼ to full circle patterns, sidespray and microspray. turf areas. •Operating schedule every 2 days

1 Adapted from:Holzworth, E., Culbert, D. & Scotto, L.:Windsor Water Conservation and Water Quality Workshop WorkbookBeach:. Vero UF/IFAS Indian River County Extension Service, September 2001.

Common problems •Obstructed patterns caused by shrubs and turf – creates too wet and too dry spots •Broken sprinklers •Clogged sprinklers •Misdirected sprinklers (leaning or pattern outside intended area •Automatic rain shutoff device not functioning •Irrigating established native plants. Recommendations •Reduce schedule from every other day to 12 times per week depending on season. •Maintain automatic rain shutoff device. •Prune shrubs to allow full range of sprinkler pattern •Adjust sprinklers to avoid spraying of sidewalks and roads. •Zones where native plants are established could be shutoff •Weekly inspection and maintenance of irrigation systems. Irrigation System Evaluation Steps Tools required for system evaluation: ™Five gallon bucket ™Catch bottle – gallon water jug ™Stopwatch ™Liquid measuring device – graduated cylinder or similar in milliliters ™Measuring tool (for irrigated area) – wheel, tape, (or estimate by pacing) ™Coring tool – for feel and appearance of moisture in rootzone ™Special – saddles with hoses for catching discharge on rotors ™Worksheet with formulas – pencil or dry ink marker ™Calculator ™Survey flags MIL Irrigation Audit Procedure ™Locate time clock – note number of zones, minutes per zone, and frequency of operation in days. ™Locate and inspect automatic rain shutoff device. ™Take core sample for feel and appearance of soil in rootzone ™Turn on zone ™Perform visual inspection of each zone with checklist and note obvious problems: ƒBroken pipes and sprinklers ƒTurf, shrub or other interference ƒRotors and sprays  turf and shrubs  on same zone ƒClogged nozzles ƒErosion ƒExceptionally wet or dry spots ƒPlant condition

™Catch water at sprinklers – measure the volume ingallons per minute ™Measure flow rates of sprinklers. ™Measure irrigated area in zone. ™Take core sample for feel and appearance of soil in rootzone. ™Do calculations to determine operating time and reset clock if appropriate. ™ Make necessary adjustments to sprinklers and prune shrubs. ™ Advise homeowner and/or irrigation contractor of needed repairs System Flow rate evaluation proceduresReview and complete the worksheet ™Catch volume in milliliters (ml)÷seconds x 0.016 X number of heads = gallons per minute (gpm) (discharge rate) ™Add all discharge rates total gpm ™GPM÷area in zone x 96.3 = inches per hour (iph) (application rate) ™Required iph÷______current iph x 60 minutes = minutes run time

An Example………………. For a zone with the following kinds of spray heads 4 heads7.83 seconds¼ spray – 370 ml ½ spray – 750 ml8 heads7.58 seconds full spray – 1600ml8.02 seconds3 heads 6.50 seconds3 headsside sprays – 270ml  50′

15′ 1′  50′

Example Calculations: ¼ 370÷gpm7.83 x 0.016= 3.02x 4 ½ 750÷7.58 x 0.016= 12.66 gpmx 8 full 1600÷ 8.02 x 0.016x 3= 9.57gpm side 270÷gpm 6.50 x 0.016 x 3= 1.99  total27.24 gpm 27.24 gpm÷96.3 = 3.28 iph800 sq.ft. x .50 iph÷3.28 iph x 60 minutes = 9.15 minutes = 10 minutes

WORKSHEET pattern #heads ◔ 1/4 ______________ gpmml x 0.016x =  sec ◑ ml x 0.016x =1/2 ______________ gpm  sec ● gpm= _______0.016 xml xfull ______  sec sidespray x =_______ gpm ______ mlx 0.016 ►◄  sectotal gpm  total = iph_______ gpm x 96.3 sq.ft.  _______"minutes =_________ minutes run timerequired x 60 iph ml = millilitersgpm = gallons per minuterequired = ¼” – ½” sec = secondssq. ft = square feetiph = inches per hour .016 = a factor to convert ml per second to gpm96.3 = a factor to convert gpm÷sq. ft. to iph

FYN:The Florida Yards & Neighborhoods Program

People like these practices –yourcustomers have told us that they : •Believe caring for the environment influences their landscaping practices •View FYN practices as easy •Feel that their use can save $, water andpesticides •Want to use these water efficient practices Nine Principles of Florida Friendly Landscaping Principles:Practices : 1. Right plant, right placeUse plants adapted to the soil, light and humidity 2. Water efficientlyIrrigate deeply at long intervals 3. MulchingDon’t mow too low 4. RecyclingLeave clippings in place 5. Fertilize appropriatelyUse slow release granular fertilizers 6. Manage yard pestsAvoid unnecessary pesticides 7. Provide for wildlifePlant or keep plants that feed or shelter birds & butterflies 8. Protect the waterfrontKeep clippings out of water and storm drains 9. Reduce stormwater runoffCheck rainfall shutoff devices For a healthy Florida Yard, use appropriate landscape management Benefits of efficient irrigation: SAVE $$$$$$ and reduce water bills  Save60,000 + gallons per year on a ¼ acre lot Reduceother maintenance requirements Initial cost of a waterefficient landscape may be higher, but payback is less than 3 years Excessive watering makes plant pest populations rise  Commonturf diseases: Dollar Spot, Gray leaf spot, Brown patch, Takeall root rot Insect infestations increase: sucking insects like new growth Root rot develops – on both new plants and established specimens Weed infestations increase – especially dollar weed While most of these pestscanbe managed with chemical pesticides, they are easy to manage if you reduce excessive irrigation water. Excessive water also stresses desirable plants in the landscape:  Nutrientsare leached from the soil = deficiencies in plants  Stressedplants cannot compete with pests  Pestswill take advantage of the holes they leave behind Work smart – work with Nature