GARDENING : In Drought, Planning Can Sprinkle Water Around
In these days of raised water-consciousness, few things are more annoying than seeing a gutter with a small river of precious runoff from a sprinkler left running long after the lawn has been soaked or watching broken sprinkler heads soak sidewalks or walls instead of landscaping.
This doesn’t have to happen.
The overwatering that causes runoff can be avoided. And broken sprinkler heads can be fixed.
In fact, properly adjusted and maintained sprinkler systems can help homeowners save water, money and time. And by learning good water management, homeowners can actually make plants healthier and less prone to disease.
One approach that saves both time and water is to convert a manual sprinkler system into an automatic one by adding a timer/controller. Then you don’t have to remember to turn the system on or off and this helps cut down on overwatering, saving water and money.
A good controller takes care of everything. A variety of controllers are available--from basic models that cost $40 up to computerized versions that are $1,000 or more.
Another approach is to replace broken equipment or install a more efficient sprinkler system when an old system is poorly designed. This helps avoid the waste of water and ends the problem of overwatered spots and dry spots.
Special devices can be incorporated into sprinkler systems to make them even more efficient. Moisture sensors keep sprinklers from cycling on when the ground is still moist. Rain sensors turn off sprinklers when it’s raining.
Efficient use of sprinkler systems is important today because Orange County homeowners could reduce landscape water use by 30% if they understood how to use sprinklers efficiently, particularly on lawns, according to Mike Robinson, assistant administrator and public information officer for the Yorba Linda Water District.
That’s why efficient sprinkler use is part of a free, three-hour class the district held earlier this month at the Yorba Linda Education Center. People attending the class on xeriscapes--landscapes with climate-appropriate and drought-tolerant plants--received a packet of materials, including a watering guide that helps gauge the water output of sprinklers and shows how to cut back on water use without harming plants and lawns.
Knowing about sprinkler-system maintenance is important because as much as 25% to 50% of landscape irrigation water probably is wasted by improperly operating sprinkler systems, poor sprinkler nozzle selection and overspraying onto sidewalks and driveways, according to Robin M. Tullener of R.M. Tulleners Landscaping in Laguna Hills.
The most common sprinkler problems are:
Broken sprinkler heads or valves, which cause flooding.
An old main water supply line clogged with residue, which restricts water pressure and limits sprinkler output.
The wrong size or type of sprinkler heads or too few sprinkler heads, which gives poor coverage and leads to a tendency to overwater to try and reach all the area that needs to be watered.
A main line can be replaced with new pipe and broken heads and valves are relatively easily fixed, but some problems are not so easy. If a system has too few sprinkler heads--not enough to cover watering needs in about 10 minutes--it might be best to just start over, according to Bobby R. Simpson of Simpson Irrigation in Garden Grove.
Carol and Charles Manger of Laguna Niguel decided on a whole new sprinkler system when they were renovating the one-third-of-an-acre yard of their 5-year-old home. They were adding a tropical look with philodendrons and lots of palm trees, including fish tail, queen and sago varieties. The front yard has some small lawn areas and beds and planters with the palms and lots of azaleas and impatiens. The back lawn is about 1,500 square feet.
“We had a lot of sprinkler heads that were spraying toward our house and toward our foundation and we have a lot of wood windows and they were getting a lot of moisture all year long,” says Charles Manger, a Laguna Hills ophthalmologist.
He realized there was a problem when the wood window frames had to be painted frequently. He was afraid the moisture would eventually damage the stucco and rot out the windows.
Manger was also having a problem with broken sprinkler heads in lawn areas. His two young children and their friends romped on the lawn and frequently stepped on sprinkler heads and broke them. And he wanted a control valve system that was easier to operate and understand than his existing one, when it was necessary to override the timer. The only portion of his old system that he wanted to retain was the computerized control system, which he found easy to operate and dependable.
The new sprinkler system has heads that spray away from the house and windows, and pop-up heads in the lawn and in flower bed areas near walkways. Pop-up heads are installed flush with the ground and only come up when turned on. This makes them less likely to be broken when stepped on. Bubblers, which are sprinkler heads that have a low volume of water flow and trickle water down instead of spraying it up, were used in narrow planter areas.
Manger hasn’t noticed any savings on water yet, but he’s only had the system a couple of months. However, he is satisfied with how the system has solved his other problems.
The Manger sprinkler system is divided into 10 zones or circuits. Each circuit has a control valve. This allows the system to water in one circuit, turn off and water in the succeeding circuits.
Homes with tract-size yards usually have about six zones, three in front and three in back. This is necessary because there wouldn’t be enough water pressure to run all the sprinklers at one time.
Having several circuits or zones in a yard also allows timers to be set to spray some areas of the yard with less frequency or for different lengths of time than other areas.
When you are considering having a sprinkler system installed or renovated, it’s wise to select someone who is licensed and can provide at least two or three references of past customers.
“Find someone who’s been in the business (for several years) and has a good reputation,” says Elmer Brown of Elmer Brown Sprinkler Co. in Placentia. No one becomes “a sprinkler expert overnight,” he says.
Landscape architects are licensed to design sprinkler systems.
Landscape contractors and sprinkler companies should also be licensed and may do design and installation.
Landscape contractor Dave Kull of Regional Land Systems in Irvine cautions against using cost as the only criteria for selecting a sprinkler or landscape contractor company. The company submitting the lowest bid on a job may use inferior equipment, Kull says.
“So, it costs less up front, but over the life of their landscape, it’s gonna end up costing them a lot more in increased water and breakage and so forth,” he says.
Kull estimates that equipment and installation of a sprinkler system might cost from 35 cents to 75 cents per square foot of landscape.
Tullener says that a sprinkler system for a 60-foot-by-100-foot lot might be about $2,000 for a four-valve system.
Once installation has started, it’s also important to keep track of what’s happening. “Just don’t turn the job over to this guy and fail to go back and check and inspect,” Simpson says.
If you study what’s available in sprinkler systems before you seek bids, you can ask about things such as mini-sprinkler heads or bubblers for small areas or the use of drip irrigation for hanging plants and potted plants, and low volume heads and matched precipitation.
Areas like embankments or slopes require sprinkler heads that have a low volume of water, so that the ground will be saturated slowly, according to Brown. If sprinkler heads with a high volume of water are used in this situation, a serious runoff problem will exist.
Kull says that heavy clay soil is characteristic of most of Orange County and that low-volume or low-precipitation heads are preferable. Heavy soil has a limited ability to absorb water rapidly and there is less runoff with low-precipitation heads. And, since the water is absorbed slowly, the soil stays moist for a longer period of time.
Matched precipitation means that all the sprinkler heads are matched to deliver the same amount of water. An area might be covered with a combination of heads that spray anywhere from a full circle of 360 degrees, down to a one-eighth head, which has a radius of 45 degrees. These heads all need to operate at the same flow rate, according to Kull.
That means, if a full circle head that has a distance of 10 feet delivers 1 gallon per minute, then a one-half head with a 10-foot distance should deliver only half a gallon a minute. This allows an area to be irrigated evenly. Otherwise, some areas will be overwatered and others will be underwatered.
Kull also suggests looking for a system that has dual programs, which will permit both sprinkler heads and a drip system.
Moisture sensors are another consideration.
Simpson, who has an associate Ph.D. in molecular physics, believes moisture sensors can save considerable water. He has developed a moisture sensor that is installed as part of a sprinkler system. It has a probe that measures hydrogen ions in the soil as a way of determining how moist the soil is. His device sells for $30-$60 each for residential use and is most effective if one is installed at the control valve for each zone or circuit.
A moisture sensor works by preventing a controller from turning sprinklers on when there is still moisture in the soil.
When selecting a moisture sensor, Simpson says it is best to get one that has a good guarantee against manufacturing defects and against dissolving in the soil, which has been a problem with some types of sensors. He also says the sensor should be guaranteed to provide at least a 20% saving of water.
Some in the sprinkler industry question the value of moisture sensors, but Kull finds them useful.
“My own personal feeling is even the least accurate moisture sensor is going to be more accurate than the average homeowner, who doesn’t have a clue,” he says.
Kull says that even if a moisture sensor was off by 10%, it could still save considerable water, because the average homeowner overwaters by 20% to 40%.
