Want A Lovelier Landscape? Master Your Irrigation Controller

By Warren Tenney

More than half the drinking water used in the Phoenix Metro area is used outdoors, mostly to irrigate landscapes. Desert dwellers irrigate a variety of plants, trees and grass all year long as the weather swings from extremely hot to freezing. Establishing a lovely landscape can mean a steep and expensive learning curve. It doesn’t have to. There are two important and easy lessons to maintaining a pretty and water-efficient yard in the desert. First, understand how much water your plants, trees and grass need to thrive. Second, learn to set your automated irrigation controller so it waters for maximum health, beauty and efficiency. AMWUA cities offer homeowners free classes, publications and videos to help.

The efficiency of an automated irrigation controller is directly related to the competence and knowledge of the person setting the controls. To keep any established desert-adapted landscape thriving the controller needs to be set to water infrequently but deeply. People who are not used to daily sunshine eagerly water their trees, cactus and shrubs a little every day. It’s a common practice that wastes water and threatens the life of any landscape. For example, you can program your controller to water your grass 15 minutes every day and your grass will stay green. The problem: you could be using two and half times the amount of water your grass needs to thrive. You can water your tree 15 minutes every day but frequent, shallow watering means your tree will never grow roots deep enough to stand up to monsoon winds. Here are general watering rules that help. AMWUA has links to more complete watering guides.

  • Water once a month in the winter, once every two weeks when temperatures begin to rise in the spring, and once a week in the hottest and driest part of the year, usually late May until the monsoon brings rain and higher humidity in early July.
  • When you do water, water to a depth of 3 feet for trees, 2 feet for shrubs, 1 foot for smaller plants and a half foot for grass. (You can measure the depth of your watering with something as simple a wooden stick.)

The second step is learning to adjust an automated irrigation controller to match what you’ve learned. Typical controllers are not difficult, but they can be confusing at first. People can’t tell the difference between station A and program A and don’t want to deal with it. They set it once and forget about it or leave it up to a landscaper. Watch the manufacturer’s how-to video designed for your controller. Then you can set it yourself and save water and money. Irrigation specialists recommend re-programming a controller at least four times a year to match the seasonal needs of your landscape.

Rachio 01

This irrigation controller can be programed with a cell phone app. Photos: Jeff Lee

Newer automated irrigation devices are known as smart controllers. If programmed correctly, these controllers adjust for seasonal changes on their own based on weather data. This technology has been used to irrigate city parks, golf courses and farms for decades. Now this technology is being perfected for back yards.

Some of these controllers adjust themselves according to historical weather patterns and an onsite temperature sensor that’s part of the control box. Many of them come with rain gauges attached or ones that you can add. Other types of smart controllers use a manufacturer’s cell phone modem to attain current weather conditions. These controllers are more precise but require a monthly subscription fee.

The latest smart controllers use your home’s Wi-Fi connection. They allow you to program and adjust them from an app on your cell phone and connect to the closest weather station for daily meteorological conditions. These controllers are easier to use but need more initial input to set up. Owners are asked to answer questions such as kind of plants being watered, type of soil (clay loam in central Valley, sandy loam in higher, northern parts of the Valley), sun exposure, sprinklers or drip, and slope. The manufacturer’s videos help answer these questions.

Rainbird ESP SMTe 01

This irrigation controller comes with a sensor.

Rainbird ESP SMTe Pod 01 SENSOR

The sensor measures both temperature and rain.

You can find smart controllers that include soil sensors. These soil probes let the controller know exactly how much water is in the soil. Due to mixed landscapes – with different trees, plants and grass – and different sun exposures these can be more challenging to configure.

Some cities will offer homeowners, HOAs and businesses rebates for installing new WaterSense approved smart controllers. Residents can make an appointment with the Town of Gilbert’s irrigation specialist to come to your home and help you set a smart controller. One precaution: When buying any smart controller make sure it allows you to do more than just adjust run times. These types of smart controllers are made for other climates and will not water long enough in the winter to reach the roots of your trees and plants. Desert yards require a smart controller that adjusts both run time and frequency (or how many days between watering). This allows you to adjust the controller to meet the needs of desert-adapted landscapes by programming to water deeply all year but less often when it’s cooler.

Right now, AMWUA cities are offering free landscape classes about watering and irrigation systems. These classes can make maintaining a lovely and water-efficient yard far easier.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

Why Are We Still Using Flood Irrigation In The Desert?

By Warren Tenney

Flood irrigation can be a surprising sight in a desert Valley. Water comes pouring out of ditches, covering large parks, ball fields or yards in what looks like deep storm runoff. While the rest of us are using drip lines and sprinklers, this sort of watering is difficult to understand. Here are the facts about flood irrigation in the Valley.

A Little History: Flood irrigation is a vestige of the Valley’s agricultural roots. Phoenix area farmers and ranchers had been brought to near ruin by the devastating cycles of flood and drought. At the turn of the century, these farmers and ranchers pledged their land – totaling 200,000 acres – as collateral to obtain a loan from the federal government to build Roosevelt Dam.  The dam allowed the fledgling community to manage cycles of drought and flood.  Each acre of land that was pledged as collateral represents one share in the Salt River Valley Water Users Association (today part of Salt River Project), the public corporation formed to secure funding for the dam. Those shares are tied to each acre, or portion of an acre, and the shares transfer with the land.  Shareholders are entitled to vote in the SRP elections of governing representatives.

Irrigation brochure

PHOTO: Salt River Project

In Arizona, the rights to surface (river) water are tied to the land by law.  Those lands where the water was put to use first have superior rights, and court determinations affect the distribution of surface water supplies.  In 1910, a court decision called the Kent Decree determined which lands were entitled to receive water stored behind Roosevelt Dam in Roosevelt Lake.  These lands, totaling 240,000 acres, are the SRP service area. It spans portions of Maricopa, Gila and Pinal counties, including from the City of Mesa and west to the City of Avondale. SRP is responsible for accounting and delivering that water.  These lands are entitled to a predetermined allotment of water.

 

A Big Change: Over the decades, the SRP service area became increasingly urbanized. Farms were subdivided into residential neighborhoods.  The shares in the Salt River Valley Water Users Association transferred with the land to homeowners and businesses. The rights to water from SRP, also tied to the land, transferred to the new landowners.

The new landowners frequently decided not to take their water via flood irrigation.  Their allotment of raw water was instead delivered to growing cities and towns to treat and deliver to the residents and businesses within the SRP lands.  Over the decades, that trend continued. Today, the majority of the water delivered by SRP (about 85 percent) goes directly to municipal water providers.

lake in a park

PHOTO: Salt River Project

The water still provided by SRP for flood irrigation is untreated and delivered largely by gravity through open canals.  The cost of this raw SRP water is low because the investment in construction of the system was made long ago and the cost of water is subsidized by SRP’s energy sales. However, municipal drinking water is significantly more expensive. There is considerable cost to treat raw water to meet drinking water standards, to maintain the treatment plants and the massive miles of mains and pipes and meters, and to employ professionals to maintain and operate that system.

The Pros and Cons: Flood irrigation isn’t necessarily as bad an idea as it appears, at least not for turf and large trees. Many old and beautiful trees, including fruit and nut trees, wouldn’t survive without flood irrigation. The main benefit is it quickly irrigates at infrequent intervals. The water soaks deeper, limiting build up of salinity in the soil (which can damage turf and plants) and encouraging deeper roots.

Cities run on tight budgets and water is a huge expense.  Where they can, cities use recycled wastewater for irrigation, but that, too, requires costly treatment and a separate distribution system.  (Virtually 100 percent of Phoenix and Tucson area recycled water is put to beneficial use.)  If a city has the right to use cheap, untreated flood irrigation for ball fields and parks instead of installing an irrigation system that uses more costly drinking water, it is understandable they would take the opportunity to save taxpayers money.

2003 Annual Report

PHOTO: Salt River Project

The homeowners on SRP lands also have rights to flood irrigation, but most have opted to no longer take it. Only about 22,000 homeowners receive flood irrigation, about 5 percent of SRP lands. Using flood irrigation can be inconvenient.  Homeowners must get up in the middle of the night to open and shut the irrigation gate on their property. The ditches are the private property of homeowners. Some neighborhoods have abandoned flood irrigation because of the cost of maintaining and repairing aging delivery ditches. Other neighbors have come together to save flood irrigation and agreed to tax themselves to cover the cost of professional repair and maintenance of the ditches. (Arizona law permits special taxing districts. These particular taxing districts are called Irrigation Water Delivery Districts.)

For more than 35 years, AMWUA members and its partners have worked toward more water-efficient, environmentally friendly landscapes. We have made considerable progress.  Back in the 1980s, 70 percent to 90 percent of residential properties in the city of Phoenix had turf landscapes.  Only 15 percent do now.  Flood irrigation is becoming a thing of the past.

The downside of eliminating flood irrigation is that it is more expensive and energy-intensive to treat raw water to drinking standards and then use it to irrigate turf and plants. Even if plants are drought tolerant, they will likely require some irrigation in an arid, urban and increasingly hot environment. Trees, plants, and turf provide shade, reduce energy demands (and the water needed to produce energy), filter pollutants from storm water, improve air quality, and provide places to rest and recreate. Learn more about flood irrigation from Salt River Project. 

For now, flood irrigation is part of our history that saves money and energy.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit amwua.org.

Dirty Secrets: Backyard Composting Among Cities’ Free Landscape Classes

By Warren Tenney

AMWUA cities offer more than 70 free landscape classes throughout the year to help you grow a more beautiful yard with less water. Local experts introduce you to a wide variety of desert plants and how to use them to design shady and colorful spaces that attract birds and butterflies. Topics also include how to select, plant and nurture trees, how much and when to water, how to grow vegetables and herbs in the desert, and how to operate your irrigation controller. This fall the City of Glendale is offering five classes, including one called “Backyard Composting.” 

There are several reasons why desert dwellers put time and energy into becoming backyard composters. Some talk about the magic of science that turns their kitchen scraps and yard trimmings into something that looks like rich, dark soil. For others, it’s about growing the best tomatoes on the block or creating a booster for container gardens. People who take the time to compost will tell you they want to decrease the amount of garbage they pack into large plastic bags and send to landfills. When compost – officially called a “soil amendment” – is used on trees, plants and vegetables the water is more readily absorbed. That can make deep, infrequent irrigation more effective and help you use water more wisely.

Here are just a few tips about basic backyard composting that you’ll learn at the Glendale class offered 6 p.m. Nov. 8 at the city’s Main Library. 

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Composting containers can be bought at any gardening store.

Container: Compost containers must be at least one cubic yard (3 feet by 3 feet by 3 feet) to get the kind of microbial activity you need to create compost. You can buy a container specially made for composting through a gardening outlet. You also can check with your city’s solid waste department. Some cities recycle old trash and recycling cans into inexpensive compost bins. They remove the bottoms, drill holes in the sides to facilitate aeration, and keep the lid on to help prevent evaporation.

Composting material: Anything that once grew roots and leaves – or is made from something that once grew roots and leaves – is a suitable composting material. You need nitrogen (often green) and carbon (often brown) to create compost. Nitrogen is most likely supplied by your kitchen waste, such as the woody stems on asparagus and broccoli, a celery stump or the lettuce you forgot about in the back of the refrigerator. Dried landscape materials supply carbon, such as wood chips from a trimmed tree limb, dried leaves or a pile of lawn clippings left in the sun for a week. (Fresh, green lawn clippings are a source of nitrogen). The smaller the size of the composting material the quicker it changes into compost. Never use bones, grease or meaty leftovers in a compost pile. These food items need different microbes to decompose. Never use cat or dog droppings, or droppings from any animal that consumes meat. These droppings harbor unhealthy bacteria that composting does not destroy. It’s fine to add manure from cows, horses, goats, rabbits or llamas. 

Oxygen: The composting material changes into compost through the work of microbes. These microbes need oxygen. They get that oxygen when the compost is “turned” or churned. The more frequently the compost material is turned the more oxygen the microbes get, the harder they work and the faster the compost is finished. Some composting containers come with a handle that turns and tumbles the composting material. Other gardeners prefer to simply transfer their material from one container to another with a shovel. 

Water: Composting microbes also need water. In the desert, compost bins tend to dry out. (Turning your compost by hand lets you find dry spots.) Your compost material should be warm in the middle and as moist as a wrung sponge. If you squeeze it and water comes out, it’s too wet. Add carbon with some dry materials. If the pile is crispy, it’s too dry. Sprinkle it with water and add some nitrogen.

Patience: Finished compost equals 40 to 50 percent of the volume of composting material used. A single typical compost bin could produce one to two wheelbarrows of compost in 6 to 10 weeks. Finished compost is rich, dark, soft and earthy. If your compost still has chunks, microbes are still working. Instead of helping your plants, microbes in unfinished compost will draw nitrogen from plants and soil to stay alive.

So, you just can’t see yourself chipping, shredding, collecting and turning your way to compost? AMWUA has a list of free city landscape classes on its website. Take a look. You’re likely to find a class you need. Some cities are offering classes right now. Others will be posting soon.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org