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Tomatoes 2008
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When landscape and irrigation professionals refer to low-volume irrigation, they may not be referring solely to drip. Low‑volume irrigation encompasses the delivery of water to the landscape through drip, bubbler, microspray and/or porous tube irrigation methods. To avoid confusion, be sure to refer specifically to drip irrigation when asking a landscape or irrigation professional for guidance. Drip seems the most practical and efficient of these irrigation methods for the Middle Rio Grande Valley. When properly designed, installed and managed, drip efficiently maintains the optimal range of moisture in the soil at all times, because it applies water in precise quantities on a precise schedule. Water is saved and plants are healthier. There are six steps to a successful drip irrigated landscape:
Typical Applications Drip irrigation is appropriate for numerous residential and commercial applications. Use this guide in combination with the City's Xeriscape Guide to help select and place specific plants in your landscape. The Xeriscape Guide also can serve as a water‑use guide for determining the number and placement of emitters for each of these plant categories. Desert Accents and
Succulents Many of these attractive Southwest species require limited drip irrigation for establishment, then thrive in the Desert with only occasional supplemental water after the first year. These plants are ideally suited for drip. Targeted applications of water nourish plants without unnecessarily irrigating the surrounding landscape. Flowers and Flowering
Groundcovers By using drip to place water at the plant base, healthy flowering plants erupt with colorful blossoms, while weeds, grass and other landscape invaders that aren't receiving regular irrigation water decline. Ornamental Grasses These grasses add green color and attractive winter/sum mer dimension to your landscape, without requiring excessive watering in the Desert. Their deep roots drink water located lower in the soil profile, requiring less frequent, but longer irrigation runtimes. Shrubs and Trees Because of their size, many of these species may require larger volumes of water. Flow rates for various drip emitter products range from 0.5 gallons per hour to 24 gallons per hour, providing the flexibility to match a variety of tree and shrub watering needs with your system. WHEN YOU ALREADY HAVE A SPRINKLER SYSTEM.. Products are available to help you convert lawn sprinklers to multi‑emitter drip "hydrants" or 1/2‑inch flex ble "poly" tube. To decide if conversion is a practical option, consider these issues: Watering Zone Layout‑Be sure you have an entire sprinkler zone that can be dedicated to the drip system. Because of sig. nificant variations in required pressures and scheduling, you cannot have sprinkler heads and drip emitters operating off of the same valve. Valves and Backflow‑Many sprinkler valves cannot function properly at low flow rates. Check with the manufacturer or dealer to see if your existing valves are suitable for low volume applications. You also need to assure that your back. flow device can function properly at low flow rates. Pipes‑If your pipes are galvanized metal, consider replacing them with PVC plastic. Galvanized pipes usually have corrosion and mineral flake that can clog emitters. If you have PVC pipes in good condition, they can be used for your drip system. Filtration‑Some manufacturers make specialty devices that replace sprinkler heads. Some of these devices are multiemitter hydrants that contain built‑in pressure regulators and small‑capacity filters. If you choose to use these devices as your sole source of filtration, you must commit to clean each device frequently. If you don't use these multi‑function devices, you will need to install a pressure regulator and filter (discussed later). Even if you are performing a conversion, many the design guidelines in this manual will apply. STEP 1 EVALUATE YOUR XERISCAPE SITE Begin the design process for your drip system with some site observations. Pay careful attention to soil type, slopes, microclimates and plant species. SOIL TYPES Coarse (sandy and/or gravelly) soils feel gritty or bumpy to the touch. Water percolates downward quickly in this soil type, leaving an egg‑shaped, vertical pattern in the soil profile. Horizontal movement of water is minimal; therefore, frequent, short irrigations keep soil moisture levels adequate for healthy plants. Once you irrigate past a plant's rootzone, that water is wasted. Medium loamy soils feel neither gritty nor smooth. Soil particles in this soil type are closer or "tighter." Water percolates slower, and the soil has better water‑holding capacity, leaving a soil profile pattern the shape of a cereal bowl. These soils are more receptive to longer, less frequent irrigations. Always watch for standing water or runoff, which indicate that you're overwatering. Fine, clay soils feel very smooth in your hand. Water in clay soil tends to spread horizontally, leaving more of a pancake‑shaped pattern in the soil profile. Because soil particles are so much smaller and closer together, clay soils have a higher water‑holding capacity. If you can match your water application rates to the soil's ability to absorb it, water remains in the soil profile much longer, improving your plants' ability to better utilize it. Drip is a great irrigation tool in tight, clay soils, because the volume of water applied is so small. Clay soils are notorious for creating irrigation runoff, because water can't seep downward as quickly. If your irrigation system applies water faster than the soil can accept it, water runs down the curb and into the storm drain. If you're experiencing runoff while watering, try watering half the amount, twice as often with some time in between (for example, instead of running one continuous cycle, divide the time in half and run two cycles with a half hour or more between).
Soil Infiltration and Wetting Pattern LOCAL SOIL TYPES In Albuquerque, there is a wide variety of soils. Generally, you will find coarse, gravelly soils in the Heights. These soils enable irrigation water to percolate down through the profile faster, with less water‑holding capacity. Clay and silt loams are common in the Valley. These tighter soils have a greater water‑holding capacity, but are more prone to runoff. On the West Mesa, sandy soils tend to offer small, deep wetting patterns with lower water‑holding capacity. Many landscape sites in Albuquerque are prepared with fill dirt of various soil mixtures, and some are heavily compacted by construction and foot traffic. These factors also affect how the soil will accept and hold irrigation water. Slopes also affect water movement in your landscape, often producing runoff. Hills and berms are particularly suited for watering with drip. On a slope, place your irrigation fines and emitters above the plant material. Pay careful attention to place the emitters within any watering wells that you create around your plants. Slopes can create microclimates. Plants on south and west slopes are exposed to more direct sunlight, heat and wind than those on the east and north side of a slope. In low spots, you may have to adjust how much irrigation water is distributed from your system, as water tends to collect in these areas. This is usually a good location for medium and high water‑use plants. Also consider how rain water (off your roof and out of your gutters) can be used to water your landscape. Designed together, drip irrigation and rainwater harvesting systems significantly advance water conservation and healthy plants. The City has produced a Rainwater Harvesting Guide to assist in designing (or redesigning) your landscape to better use the 9 or so inches of Nature's precipitation we receive free. MICROCLIMATES IN A LANDSCAPE MICROCLIMATES Most of us understand Albuquerque's climate during the irrigation season (generally March through September): windy, warm springs and falls with occasional cold nights or snow; hot, dry early summers; and hot, humid monsoons in July and August. Annual precipitation averages about 9 inches, much of which falls in the monsoon season, with otherwise sporadic rain and snow events throughout the year. However, every yard has its own microclimates that affect how much water specific plants will need. For example, plants in the south and west areas of your landscape may face hotter, windier conditions than those north and east of buildings, walls, fences or slopes. Plants in direct sunlight surrounded by asphalt will need more water than those in shady areas on the north side of your home. In upcoming pages, we will help you make irrigation adjustments to compensate for the microclimates on your property. Be sure to consider microclimates in both your planting and irrigation designs. STEP 2 DESIGN YOUR PLANTINGS AND DRIP SYSTEM INTO HYDROZONES DESIGN OVERVIEW Design your landscape and your irrigation system ‑ in zones, grouping plants together based on similar water needs and microclimates. These "hydrozones" don't have to be little bunches of plants dotting your property ‑ they can be grouped in whatever patterns are pleasant and practical for your landscape. In addition to assuring a healthy environment for your plants, hydrozones, help simplify xeriscape and irrigation design and management requirements as your yard matures. DESIGNING YOUR
PLANTINGS If you are planting a new site, you can control how your plants are grouped, arranging the landscape so that plants with similar water requirements are grouped together. Then these hydrozones can naturally follow the physical layout of the site. Consider these general hydrozoning principles in your landscape design: Zone 1 ‑ Mini‑oasis: The area nearest to your house is where the highest water‑use plants should be placed. Shade and rainfall runoff from your roof can contribute to creating the lushest zone with less supplemental water. Zone 2 ‑ Transition: The transition zone is used to blend lush areas with the drier parts of your landscape. Try to select low and moderate water‑use plants that need infrequent supplemental watering. Zone 3 ‑ Arid: Feature the most drought‑tolerant plants in the and zone, the driest part of your landscape farthest from your house. Native and droughttolerant plants are ideal, as they require only deep, infrequent watering after establishment. Existing sites can be more challenging to design. On many projects, plants with very different watering needs are located next to each other. This is a strength of drip ‑ the ability to target precise applications of water plant‑by‑plant. For example, if you have an area that contains plants with differing water needs, you may want to group them into separate irrigation hydrozones according to low, medium and high water requirements. These hydrozones can be designed by adjusting the number and size of emitters or by adding more than one independently valved dripline. Don't overlook the important issues below when you design your landscape (consult your Xeriscape Guide for suggestions):
STEP 3 DESIGNING YOUR DRIP SYSTEM A DRIP SYSTEM CONSISTS OF SIX MAJOR COMPONENTS:
THE CONTROLLER Consider the following features for greatest flexibility and water efficiency:
Visit an irrigation distributor and ask to experiment programming some of their controllers. Consider the following issues to determine the best location to mount your controller:
FILTERS AUTOMATIC VALVES Due to the very low flow rates in drip irrigation, be sure to use low volume valves. Most manufacturers have valves capable of operating properly at 1 gallon per minute (60 gallons per hour) or less. If you are attempting to convert an existing sprinkler system to a drip system, check the manufacturer's specifications to ensure your existing valves will operate properly at low flow rates. Avoid designing a system that is near the valve's lowest flow range to assure the valve opens and closes more dependably. Choosing the best location for the valves requires you to consider several factors:
PRESSURE REGULATORS BACKFLOW PREVENTION THE DISTRIBUTION
SYSTEM They are flexible and reliable, and in the finished landscape can be covered by rock or organic mulch (which also help to hold water in the landscape). EMITTERS Barbed, punch‑in emitters, which~ are the most common, can push directly into 1/2‑inch tubing. For ease of inspection and maintenance however, consider punching a barbed connector into the 1/2‑inch tubing, connect your 1/4‑inch tubing to the barbed connector and run it to the desired location beneath the plant's canopy. Then attach an emitter to the end of the 1/4‑inch tubing beneath the plant's canopy. This way, emitters are located at the base of the plant and always accessible to you ‑ not buried by landscape fabric and/or mulch, which can complicate any possible changes or repairs later. Pressure‑compensating barbed emitters come in various color‑coded flow rates to accommodate individual plant needs. When installing barbed connectors or emitters, you may want a special tool that punctures the 1/2‑inch tubing, so you can accurately direct water to each plant with 1/4inch tubing and then emitters. Multi‑outlet emission devices, or hydrants, contain several pressure‑compensating drip emitters to which you can attach 1/4‑inch tubing that runs directly to each plant. They, too, can be color coded according to various flow rates. These devices serve as a central point from which 1/4‑inch spaghetti‑tubing" is ran. In‑line drip emitter tubing has emitters pre‑installed at specific intervals (ask a professional) or is available as individual pressure compensating emitters that attach to 1/4‑inch tubing. In this instance, 1/4‑inch tubing is snaked through the planted area, and individual emitters are solvent‑welded into the tubing at the desired location of emission for each plant. If installed correctly and inspected regularly, all of these emission devices are water‑efficient and easy to work with. Talk to an irrigation professional about what might be best for your project. STEP 4 INSTALL THE SYSTEM "NOTE: These installation instructions are general guidelines. Always follow manufacturers" instructions and local codes for the application and installation of specific products. Installing underground pipe will require that you dig trenches. Lay out your trenching plan on paper and mark key reference points in the yard with flags or landscape paint. If possible, avoid trenching within the dripline of established trees and shrubs. Your mainline trench must be a minimum of 28 inches deep between the point of connection and the valves. Lateral trenches should be approximately 12 inches deep to help protect the pipe from freezing and future excavation damage. TAPPING INTO THE WATER
SOURCE Once the isolation valve is properly installed and closed you can turn on the water to the home and proceed with the remaining sprinkler/drip system installation. Flush the connection by opening the isolation valve for five to 10 seconds, or until the water runs clear. If you are unfamiliar with plumbing techniques and codes, you may require a visit from a licensed plumber. Consult your local city or county building codes for backflow prevention requirements. In the Albuquerque area contact: 1.) City of Albuquerque Building Safety Division information ‑ 924‑3304 2.) Bernalillo County Zoning/Building/Planning Department ‑ 924‑3700. From the point of connection, run a main PVC fine at least 28 inches deep to the location you have selected in your yard for your irrigation valves and valve box. For most residential applications, 1‑inch, Schedule 40 PVC pipe is recommended. After installing your valve(s) to the mainline, install a second isolation valve, which will make it easier to maintain the filter and valves. Allow time for the fittings to adequately cure, then flush the mainline pipe to clear any debris that may have entered during assembly. Next, install your filter. "Y"‑style filters (wye strainers) should be installed with the filter canister pointing downward or sideways. A filter installed upward may allow particles to stay in the fine while flushing. THE VALVES IMPORTANT: BUILDING VALVE
MANIFOLDS If your landscape design requires more than one valve, or zone, a valve manifold will be the base onto which you will construct your lateral sprinkler or drip zones together. It is generally comprised of 1‑inch PVC pipe with "tees" glued in at specific intervals where each valve will attach, then lateral piping zones can be laid out in the landscape. For threaded PVC fittings, use one to two wraps of teflon‑type tape on the male threads (with the threaded end facing you, wrap in a clockwise direction). Do not over tighten PVC threaded fittings; they are the most common source of fitting failures in a sprinkler system. Use pipe compound for any threaded fittings of galvanized pipe required in the assembly of your backflow preventers. Before installing the valves onto the manifold, flush the system again. After each valve in your manifold install in order:
All subsurface piping including valves should be buried a minimum of 18 inches (28 inches from. the point of connection to the valve manifold). Your valve box should be buried flush with the ground. Place a layer of gravel in the valve box beneath the manifold to help keep it drained of standing water. Connect the controller wiring to the automatic valves with water‑proof connectors. Test the automatic operation of the valves from the controller before proceeding. RUN LATERAL LINES TO
PLANTED RUN DISTRIBUTION
TUBING TO PLANTS INSTALL EMITTERS Inline emitters are installed by attaching 1/4‑inch tubing to a riser in the planting bed, snaking it loosely around the individual plants, cutting the 1/4‑inch tubing with scissors at desired locations around the plants, applying a special solvent and reconnecting the 1/4‑inch tubing to run to the next plant. Ultimately these zones are closed loops that connect twice to the riser fitting. Install your multi‑emitter hydrant either at or below grade. For below ground installations, ensure that it is protected by a valve box. Then attach your 1/4‑inch tubing (in runs no longer than 5 feet) to deliver water to the individual plants. TABLE 1
Table 1 provides guidelines for the volume of water to be delivered to plants, according to size and watering needs. For example, Table 1 recommends a flow rate of 3.0 GPH for a small, low water‑use shrub. The recommended flow rate can be achieved using two 1.5 GPH emitters, three 1.0 GPH emitters or six 0.5 GPH emitters. These guidelines are suitable for most New Mexico climates and soils. TIP FINISH THE
INSTALLATION Most drip systems will be covered with mulch to hide the tubing, reduce evaporation and minimize weeds. However, to ensure that your drip system is operating properly, wait a week before adding the mulch. Check that all emitters are operating, and watch plants for signs of stress. After a week, flush the system again and cover with mulch. STEP 5 SCHEDULING YOUR TIMER The key to effective water management is to water according to weather changes and soil moisture content. The figures in Table 2 are for watering needs in normal, dry, calm weather. This table will give you an accurate runtime for low and medium water use plants adjusted for historical monthly weather patterns in Albuquerque. Water budgeting features on some timers enable you to dial up or down the percentage of your base (in this case, peak‑season July demands) watering schedule. For example, the weather demands on a land TABLE 2 ‑ Schedule for Albuquerque, NM, area
Provided you used Table 1 in the design of your drip system, you can use Table 2 as a general operating schedule for established plants in the Albuquerque area. (See scheduling guidelines for other regions of New Mexico in scape in September are only 62 percent of the demands in the back of the manual.) July. The water budget feature enables you to make a simple adjustment to all the watering programs. Water budget adjustments can also be found in table 2. ADJUSTING FOR
MICROCLIMATES * If the zone is in full sun throughout the day and/or it is surrounded by pavement or rock, increase your runtimes or emitter output by about 25 percent. If the zone is in full shade throughout the day, decrease your runtimes or emitter output by about 25 percent. IMPORTANT! STEP 6 MAINTAIN THE SYSTEM THE FIRST FOUR WEEKS Inspect your filters weekly. Drip emitters have very small openings, so it's important to have adequate filters to protect against clogging.
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