CMG GardenNotes #264 Irrigation Equipment

Transcription

1 CMG GardenNtes #264 Irrigatin Equipment Outline: In-grund sprinklers, page 1 Pp-up spray heads, page 3 Rtr heads, page 4 MP Rtatr, page 5 Strengths and weaknesses f in-grund sprinklers, page 6 Bubblers, page 6 Drip systems, page 6 Saker hses and saker tubing, page 8 Strengths and weaknesses f drip systems, page 9 Subsurface drip, page 10 Hse-end and hand watering, page 10 Strengths and weaknesses f hse-end watering, page 11 Summary, page 11 Equipment fr delivery f landscape irrigatin water ranges frm autmated ingrund sprinkler systems and drip irrigatin systems t hse-end watering. A basic utline f each with their strengths and limitatins fllws. In-Grund Sprinklers Different types f irrigatin equipment are mst effective t water varius types f planting in the hme landscape. Fr lawns, sprinkler irrigatin with pp-up spray heads and rtr heads are generally used. Because each type f sprinkler delivers water at a different rate, d nt mix sprinkler types in a zne. All sprinkler systems must cmply with lcal building cdes, requiring building permits and inspectin. In-grund sprinkler systems have the fllwing basic cmpnents. Pint f Cnnectin The system starts at the pint f cnnectin where the supply line cnnects t the water supply. This is in the basement f the typical huse. The size f the pipe and water pressure determine water flw and thus influence design f the system (hw many heads can run at ne time). A pressure regulatr prvides unifrm, lwer water pressure fr unifrm water delivery. This is typically fund just befre the pint f cnnectin. It shuld be set at 30 t 40 psi fr the landscape irrigatin system and husehld water use. Sprinkler systems have maintenance prblems and values may fail t shut ff when the pressure is abve 80 psi. Pressure regulatrs are typically nt fund in lder 264-1

2 hmes. Due t increased unifrmity f water delivery, adding a pressure regulatr may result in significant water savings in landscape irrigatin. Figure 1. Pint f cnnectin with pressure regulatr, shut-ff value fr utdr line and drain valve that drains the utdr line t the backflw preventin device (lcated just utside the huse). Lcal building cdes require a backflw preventin device t prtect the cmmunity s water supply. This is typically placed where the water line cmes ut f the huse. Sme valves have a backflw preventin device build int the value. The type t use depends n the lcal building cde. [Figure 2] Figure 2. Required by lcal building cdes, backflw preventin devices are typically lcated where the line cmes utside frm the huse. The main supply line (water line hlding water under pressure thrughut the summer) splits in a valve bx t a valve fr each zne. T minimize maintenance headaches, use Schedule 40 PVC pipe fr belwgrund supply lines and cpper pipe fr any abve-grund pipe. PVC fitting are cnnected with special glue. Cpper pipefittings are sldered. [Figure 3] Figure 3. Valve bx with tw zne valves

3 Beynd the valve, secndary lines (lines that have water nly when the zne is running) g t sprinkler heads. Being easy t wrk with, these are generally made f flexible black ply pipe. Cnnect ply pipe fitting with pinch clamps. The size f the pipe and the water pressure determine the number f sprinkler heads that can be used per zne. Varius brands f sprinkler equipment have planning bklets with specific details fr their prduct lines. A cntrller (timer) runs the system frm a central lcatin (typically in the garage). In the hme garden market, there are many styles f cntrllers with a variety f features. [Figure 4] Figure 4. Cntrller Many brands ffer a variety f features. In climates where the sil freezes, the lines need t be drained in the winter. This starts by turning ff the water with the valve near the pint f cnnectin and pening the internal drain line. This drains the line t the backflw preventin valve (which is utdrs at the high pint in the system). Depending n hw the system was designed, there are several methds t drain the supply line and secndary lines. Sme systems are blwn ut by cnnecting an air cmpressr. Other systems have valves that are manually pened, allwing fr drainage by gravity. In sme systems, secndary lines have self-draining valves that autmatically drain the line each time the water is turned ff. Pp-Up Spray Heads This is a generic name fr sprinklers that autmatically pp up with a fan-shaped spray pattern and d nt rtate when running. The head retracts by spring actin when the water is turned ff. [Figure 5] Figure 5. Pp-up spray heads are used fr small areas, 15 feet wide and less. Delivery pattern Pp-ups spray heads are best suited fr small t mderate sized hme lawn areas (larger than seven t ten feet wide up t 30 t 45 feet wide) and irregular r curvilinear areas. Pp-up spray nzzles are mst cmmn with 15, 12, 10, and 8 ft radii. The radius can usually be adjusted dwn abut 30%, using the nzzle s adjustment screw. Therefre, a cmmnly available ten-ft nzzle can be reasnably 264-3

4 adjusted dwn t seven feet. Any greater adjustment wuld significantly distrt the pattern, resulting in pr applicatin efficiency. The spray pattern f a pp-up spray head depends n chsing nzzles t water quarter circles, half circles, r full circles. Sme manufacturers ffer adjustable arch nzzles that can be set at any angle. Hwever, d nt use adjustable nzzles where a fixed nzzle wuld wrk, as the unifrmity f water delivery is nt as high. Sme specialty patterns t handle narrw, rectangular turf areas are available (ften called end-strip, center-strip r side-strip nzzles). Hwever, nzzle perfrmance is nt as unifrm cmpared t quarter-circle, half-circle, r full-circle nzzles. Within any given brand, spray nzzles have match precipitatin rates. That is, a half-circle head uses half the amunt f water per hur as a full-circle head. With match precipitatin rates, full, half and quarter circles may be used in the same zne. It is als acceptable t mix a cmbinatin f nzzle radii in a zne. Figure 6. Fr unifrm water distributin, the spray head needs t release water abve the grass height. Pp-up height Fr unifrm water distributin, the sprinkler heads shuld rise abve the grass height, making the 4-inch pp-up style mst ppular. High pp-up heads, with a 12-inch rise, are suitable fr grund-cver areas and lwer flwerbeds. [Figure 6] Pressure Pp-up spray heads wrk best with water pressure arund psi. The water pressure at sme hmes may be significantly higher, and an in-line pressure regulatr will be needed in these cases. A sprinkler prducing a mist clud arund the head is a cmmn symptm f excessive pressure. This gives a distrted distributin pattern (significantly increasing water use) and leads t increased maintenance prblems. In additin, a grade change f mre than eight vertical feet n a single zne will result in significantly higher pressure at the lwer end, creating distributin prblems. Small Areas Small areas less than seven t ten feet wide are difficult t sprinkle irrigate efficiently with pp-up spray heads. Cnsider landscape alternatives. Fr example, that small side yard between huses may be an excellent site fr a lw maintenance, nn-planted, nn-irrigated mulch area. Alternatively, the small area culd be a shrub/flwer bed watered with drip irrigatin. A narrw lawn strip may be watered efficiently with the new sub-surface drip fr lawns

5 Precipitatin rate Pp-up spray heads have a high water delivery rate (precipitatin rate) f 1 t 2½ inches per hur. At the typical rate f 1½ inches per hur, the zne wuld apply 1/2 inch f water in just 20 minutes. Rtr Head Rtr heads mechanically rtate t distribute the spray f water. Impact and geardriven heads are tw cmmn types in the hme garden trade. [Figures 7 and 8] Rtr heads in the hme garden trade are best suited fr larger lawn areas, generally 18 t 24 ft radius and greater. Sme rtr-type heads in the cmmercial line have a radius f 30 t 90 feet. Figure 7. Impact r impulse heads rtate as the water stream cming frm the nzzle hits a spring-laded arm. Impact heads tend t experience fewer prblems with marginal (dirty) water quality. Figure 8. Gear-driven heads use the flwing water t turn a series f gears that rtate the head. Gear-driven heads are quieter t perate than impact heads. The spray pattern depends n the head. Mst can be set at any angle frm 15º up t a full circle. Sme are adjusted at 15º increments. Others are designed fr a quarter-circle, half-circle r full-circle spray pattern. In rtr head design, d nt mix quarter, half and full circle patterns in the same zne. The water flw is the same fr each head, but the area cvered will be different. Fr example, a full circle (cvering twice the area f a half circle) will have half the precipitatin rate f a half circle. The full circle will need t run twice as lng t apply the same amunt f water as the half circle. Pressure Rtr heads typically perate at 30 t 90 psi, 30 t 40 psi being mst cmmn fr heads in the hme garden trade. Better quality heads have built-in pressure regulatrs. Precipitatin rate Rtrs are mre unifrm in water distributin than pp-up spray heads and take much lnger t water. As a rule f thumb, rtr heads deliver water at a rate f ¼ t ¾ inch per hur. At the typical precipitatin rate f ½ inch per hur, it wuld take 60 minutes t apply ½ inch f water. The slwer precipitatin rate can be an advantage n clayey r cmpacted sils where water infiltratin rates are slw

6 Multi-Stream Rtrs The newer multi-trajectry rtating streams, prvide unmatched unifrmity in water distributin fr significant water savings. They have a lwer applicatin rate, reducing runff n cmpacted, clayey sils and slpes. The streams f water are large enugh t resist wind disturbance, s they reduce the amunt f water blwing nt driveways, sidewalks, and rads. Several manufacturers ffer multi-stream rtrs in tday s market, including Hunter MP Rtatr, Tr Precisin Series, Rainbird R-VAN, and thers. Generally used by landscape cntractrs, multi-stream rtrs are less cmmn in the hme garden trade. Fr the hme gardener, they may be fund nline. Almst any type f sprinkler head can be retrfitted with an MP Rtatr sprinkler, including spray heads and traditinal rtrs. MP Rtatrs can apply water t distances ranging frm fur t 30 feet. They can als be used t water narrw planting strips, which are ften difficult t water effectively with traditinal sprinkler heads. Depending n the head, they perfrm best at 30 t 40 psi. With matched precipitatin rates, quarter, half and full heads may be mixed in a zne. Strengths and Weaknesses f In-Grund Sprinklers Strengths f in-grund sprinklers include the fllwing: Cnvenience Time savings Usefulness fr irrigating small areas Very efficient if well-designed, maintained and managed accrding t plant water needs (ET). Weaknesses f in-grund sprinklers are that they can be very inefficient if prly designed, maintained, r managed. Being t cnvenient, many gardeners give them little attentin, significantly wasting water. Bubblers Small grupings f flwers and ther small plants can be efficiently watered with bubblers, which fld an area and rely n the natural wicking actin f the sil t spread the water. They are ideal fr level shrub and grund cver areas. Heads are typically placed at three t five feet intervals r placed near individual plants fr spt watering. Stream bubblers are directinal and cme in a variety f spray patterns. Bubblers deliver water faster than drip emitters and are used t water trees and shrubs. Refer t manufacturers literature fr design and management criteria related t varius mdels

7 Drip Systems Fr flwer and shrub beds, small fruits and vegetable gardens, drip emitters, drip lines, micr-sprayers, and saker hses are ppular. Water use rates, weed seed germinatin, and fliar disease prblems are reduced in drip systems that d nt spray water int the air and ver the plants and the sil surface. As a rule f thumb, a drip system cupled with mulch can reduce water needs by 50%. Drip emitters, micr-sprayers, and drip lines require clean water, which is relatively free f sil particles, algae, and salts. In-line filters are part f the system. Water quality is generally nt a prblem when using ptable water surces. Hwever, with nn-ptable water surces, the filtering system required may be expensive and high-maintenance, making drip impractical. Drip systems wrk with lwer pressures (typically arund 20 psi), generally using in-line pressure regulatrs. The system snaps tgether with small fittings. N gluing r bands are required. It is much easier t wrk with if the tubing has been warmed by the sun fr an hur. [Figure 9] Figure 9. In-line filter and pressure regulatr ging t drip line ply tubing. The system is put tgether with half-inch and quarter-inch ply tubing, fittings and emitters. Fr the main line and branch lines, half-inch ply tubing is used. The quarter-inch micr-tubing serves as feeder line t individual drippers r micrsprinklers. Ideally, the tubing is n the sil surface under the mulch. Drip emitters deliver water at a slw, cnsistent rate, such as ne-half galln, ne galln, r tw gallns per hur. Emitters can cnnect t the branch line r extend n micr-tubing ut t individual plants r pts. Small annuals and perennials typically have ne emitter per plant. Several wuld be used when placed arund larger perennials, shrubs, and small trees. [Figure 10] 264-7

8 Figure 10. Drip emitter n ½ ply tubing Sme gardeners mistakenly think that using half, ne and tw galln per hur drippers is an effective methd t manage differing water needs. Althugh this wrks t a small degree, the cncept is flawed. The twgalln per hur drippers will have significantly larger wetting znes than the half-galln per hur dripper. Hwever, plants with the higher water needs (tw-galln/hur drippers) d nt necessarily have a larger rt spread. Likewise, plants with lwer water needs (half-galln/hur dripper) will nt necessarily have a smaller rt spread (in fact, a large rt spread is what makes sme plants mre xeric). The factr missing here is irrigatin frequency t match the water needs. In-line drip tubing is a quarter-inch micr-tubing with built-in emitters spaced at six, 12, r 24 inch intervals. The 12-inch spacing is readily available in the hme garden trade. These are great fr snaking thrugh a bed area. Fr sandy sils, spacing f the tubing shuld be at 12 inches. Fr clayey sils, spacing may be at 18 t 24 inches fr perennial beds. Micr-sprayers, ften held up n a spike, cver a radius f tw t 13 feet. Delivery rates vary frm 0.1 t 10 inches per hur, depending n the head selected. Because water is sprayed in the air, drift and water waste in wind resembles sprinklers mre than grund-applied drip. Micr-sprayers wrk with a very small drplet size that readily evaprates. Fr this reasn, their efficiency in Clrad s lw humidity is questinable. Specificatins n design and management vary amng manufacturers and types selected. Refer t the manufacturer s literature fr details. Typical run times are 60 t 90 minutes. Drip systems are easy t autmate by cnnecting the znes t valves and a cntrller (like an in-grund system fr a lawn). Fr ease f prgramming t the specific watering needs f the drip system, use a dedicated cntrller fr multiple drip znes. In small yards, a single zne r tw can be added t the cntrller used fr the lawn, but they wuld run n a different prgram than the lawn t match the different watering needs. When cnnected t the garden hse, the zne can be autmated with single-zne cntrllers that cnnect with hse-end fittings at the tap. Sme simple mdels turn the water ff after a set number f minutes r gallns. Mre elabrate batteryperated mdels turn the water n and ff at the day and time interval set by the gardener. [Figure 13] 264-8

9 Like any irrigatin system, drip systems require rutine maintenance. They are nt an install-and-frget type f system. Fr additinal infrmatin n drip irrigatin, refer t CSU Extensin Fact Sheet #4.702, Drip Irrigatin fr Hme Grunds. Saker Hse and Saker Tubing The saker hse is a different type f drip system that allws water t seep ut the entire length f a prus hse. They are great fr raised bed gardens and flwer beds. In sandy sils, space runs at 12 inches. Fr flwer and shrubs beds n clayey sil, space runs at inches. In a raised bed vegetable garden (where unifrm delivery t small vegetables is imprtant), make three t fur runs up and dwn a fur-ft wide bed. Typical run time is 10 t 20 minutes. Quarter-inch Saker Tubing Quarter-inch saker tubing is availble in the drip irrigatin sectin at garden stres. Cut the saker tubing t desired length and cnnect with drip system cmpnents. An in-line pressure regulatr (Figure 10) is required; therwise, the fitting may pp r leak. Half-Inch Saker Hse Sme brands (like Swans Saker Hse) are a ½- inch hse that cnnect with a standard hse fitting. Half-inch saker hses are fund in the garden hse sectin f a garden center r nursery and can be cut t any length and cnnected with garden hse fittings. A small plastic disc fits inside the female hse cnnectin as a flw regulatr. T adequately water the garden with the reduced water flw, it may need t run fr arund an hur. Fr better perfrmance, use the pressure regulatrs with hse-end fittings fund with the drip irrigatin supplies (Figure 11). T adequately water the garden with this type f regulatr, the drip line runs 10 t 20 minutes. Withut a pressure regulatr f sme type, the saker hse tends t rupture, sending ut steams f water at spts rather than dripping alng the line. [Figure 11] Figure 11. Tap, pressure regulatr (with hse cnnectins) and half-inch drip hse in raised bed garden. This half-inch hse style is mre tlerant f small amunts f dirt, algae, r salts in the water than ther types f drip systems and may be successful n sme nn-ptable water surces. Peridically, pen up the end f the hse and flush ut sil depsits. Because the saker tubing has a higher delivery rate, it cannt be n the same zne as ther in-line drip tubing, buttn emitters, r bubblers

10 Strengths and Weaknesses f Drip Irrigatin Strengths f drip irrigatin include the fllwing: Cnvenience. Water saving. Operates with lw water pressure. Easy t change when the plantings change. Des nt require trenches fr installatin. Readily autmated n a multi-zne cntrller r single-zne cntrllers that cnnect t the faucet. Weaknesses f drip irrigatin include the fllwing: Require gd-quality water and filtratin. Maintenance difficulty in seeing if systems are perating and need t check water delivery t individual plants. Cst: fr large areas, the cst will be significantly higher than a sprinkler system. Unsuitable fr watering large trees. Subsurface Drip Subsurface drip is a relatively new way t water lawns and flwerbeds. Tubes are permanently buried belw grund. Water saks upward and laterally s subsurface drip wrks in clay-cntaining sils, but nt well in sands. Generally installed by a trained and experienced prfessinal, subsurface drip requires very exact installatin depth and spacing. Withut prper attentin t installatin, the lawn becmes striped with green and dry strips. Studies cnducted by the Nrthern Clrad Water Cnservatin District find that water use is similar t a well-designed sprinkler system. Strengths f subsurface drip include: Cnvenience. Operatin at lw pressure. Equipment lcated ut f sight, where it is less prne t damage. Easy t water anytime day r night, even when the lawn is being used. Applicatin f water directly t the rt zne. Easy t autmate with sil misture sensrs. Ptential t inject fertilizers with the irrigatin water. Weaknesses f subsurface drip include: Requires high-quality water. Inability t see if it is perating crrectly and need t dig it up if it is nt. Prhibitin f inserting stakes in the grund. Requires prfessinal installatin. Relatively high cst. Evlving technlgy that has nt std the test f time

11 Hse-End and Hand Watering Hse-end watering devices include varius types f spray heads, water wands and water breakers, saker hses, and sil needles. Such devices are cmmnly used fr temprary situatins and where permanent installatins are impractical r nt desired. Hse-end watering is very inefficient in unifrmity f water delivery, resulting in high water use. Hwever, significant water savings may ccur because gardeners generally d nt water until the lawn/garden shw signs f being dry. A cmmn prblem with hand-held water wands is that flks tend t nly water the surface, rather than deep watering f the rt system. Avid sil needles because they apply the water belw the primary rt system f trees, shrubs, and flwers. A hand-mved sprinkler can be autmated with single-zne cntrllers that cnnect with hse-end fittings at the tap. Sme simple mdels turn the water ff after a set number f minutes r gallns. Mre elabrate battery-perated mdels turn the water n and ff at the day and time interval set by the gardener. [Figure 12] Figure 12. Single-zne cntrllers cnnect t the hse line. Left: This style is manually turned n and autmatically turns ff after a set number f minutes. Right: This battery pwered cntrller turns water n and ff at the day and time intervals set by the gardener. Strengths and Weaknesses f Hse-End Watering Strengths f hse-end and hand watering include the fllwing: Relative lw cst f equipment. Ability t water plants differently and usefulness fr spt watering. Allws fr clse bservatin that may result in mre timely care f plants. Being utside in the yard encurages neighbrhd relatinships. Weaknesses f hse-end hand watering include the fllwing:

12 Time-cnsuming. Pr unifrmity f water distributin with hand-placed sprinklers, leading t high water use. Hand-held watering ften leads t surface watering rather than effectively watering the rt zne. Wasting water by allwing it t run t lng. Summary Any type f irrigatin system (in-grund sprinklers, drip, r hand watering) can be very efficient with attentin t detail. Likewise, any type f irrigatin can be inefficient, wasting water. What makes a system efficient r inefficient is nt the equipment, but rather the attentin given by the gardener. CMG GardenNtes n Irrigatin Management #260 Irrigatin Management: References and Review Questins #261 Clrad s Water Situatin #262 Water Mvement Thrugh the Landscape #263 Understanding Irrigatin Management Factrs #264 Irrigatin Equipment #265 Methds t Schedule Hme Lawn Irrigatin #266 Cnverting Inches t Minutes #267 Watering Efficiently #268 Hme Lawn Irrigatin Check-Up Authrs: David Whiting (CSU Extensin, retired) and Carl Wilsn (CSU Extensin, retired). Artwrk by David Whiting; used by permissin. Revised by Kurt M. Jnes, Chaffee Cunty Extensin Directr Clrad Master Gardener GardenNtes are available nline at Clrad Master Gardener training is made pssible, in part, by a grant frm the Clrad Garden Shw, Inc. Clrad State University, U.S. Department f Agriculture and Clrad cunties cperating. Extensin prgrams are available t all withut discriminatin. N endrsement f prducts mentined is intended nr is criticism implied f prducts nt mentined. Cpyright Clrad Master Gardener Prgram, Clrad State University Extensin. All Rights Reserved. CMG GardenNtes may be reprduced, withut change r additins, fr nnprfit educatinal use. Revised Octber 2014 & September,