Water WiseIrrigation certification leads to contracts
by: Don Dale
Nothing about the technology or demands of modern irrigation techniques scares Springtime Landscape & Irrigation. The company benefits from its listing as a "Water Wise" company in Oregon, where the designation is a sign of a company's dedication to the art of creating efficient landscape watering systems.
Springtime, located in Bend, Ore., is a 28-year-old design/build company with about 75 summer employees. The company participates in some of the most modern water conserving landscape construction projects in the state.
A job that illustrates how strenuous the specs are for irrigation installation in Oregon is the city of Bend's Cooley Road project, which involved landscaping a new street extension. Springtime was hired as a subcontractor to update the design for the job and install it, as well as design and landscape a traffic roundabout. The project was done to the city's specs regarding irrigation efficiency, which correspond to the Oregon Landscape Contractors Association's (OLCA) Water Wise requirements.
About 9,000 feet of PVC and 150,000 feet of drip
line were used in about 1 mile of street landscaping in Bend, Ore.
"The city of Bend has its own Water Wise program," says Scott Anderson, Springtime sales manager and designer for the Cooley Road project. "They had a set of criteria they wanted met." Those included elements of labor, energy, fertility and maintenance savings, as well as provisions for control of stormwater and pollution and the prevention of water-related property damage.
What could be so complicated about a roadside irrigation job? The city of Bend has extensive irrigation design requirements that incorporate the latest in irrigation technology, Anderson says, and the city isn't unusual nowadays. Government entities all across the country try to install attractive landscaping while utilizing the outgrowth of modern science to provide overall efficiency.
The Cooley Road project began with the soil on easements on both sides of the street, which double as retention basins, as well as median islands. The native sandy loam soil wasn't ideal for the drip irrigation designed into the system, and the city didn't want subsequent high maintenance costs, so a multilayer soil surfacing system was designed, Anderson says. As a result, drip lines were laid on the soil, and then a 2-inch layer of compost was laid over that to provide organic matter. Over that, a fabric liner was installed to prevent weed germination from the bottom, and prevent the final top layer of river rock from encroaching on the drip system.
Chris Koch and Scott Anderson, with Springtime Landscape & Irrigation,
say that any company wanting to acquire projects with municipalities
must have crews that can work with the latest irrigation technologies.
This plan for a traffic roundabout in Bend, Ore., seems simple enough,
but it involves Water Wise irrigation techniques demanded by many
municipalities throughout the U.S.
The project required over 150,000 feet of Rain Bird .5-inch drip line, in a grid with 1 to 1.5-inch PVC supply line (9,000 feet of that along with some 2,500 fittings), and the protective top layers would enable plants to maintain contact with moisture in the soil, as well as prevent the soil from blowing. The ground would not be wet on the surface, reducing evaporation and weed germination. "It also held the drip line in place," Anderson says of the top layers. Drip line with emitters built in at 12-inch intervals, delivering .9 gallon of water per hour, was installed at 18-inch intervals to allow plantings over 100 percent of the area if so desired.
A lot of plant materials were used, and according to city and OLCA directives, they were all native or drought-tolerant plants. There were 17,000 perennials and 4,000 grass plugs, as well as 7,700 smaller plants in mixes. The bulk of the perennials were natives, such as rabbit brush and big sage bush, and some of the larger species were local natives.
"We used a lot of western juniper, which is a native here," Anderson says, and it is drought tolerant as well. Many of the grasses, such as tufted hairgrass, were also natives. In the center of the roundabout, at Cooley and 18th Street, larger trees were desired. Those were generally natives and included ponderosa pine and red maple, though curb appeal was also achieved by using plants like decorative plum. The large trees were set up on a bubbler system in addition to the drip irrigation grid designed for smaller plants. The Rain Bird RWS bubbler system overlays the other drip lines, but is on its own valve zone. The bubbler mesh tubes are dropped 24 inches into the soil, two per tree.
Rain Bird commercial drip irrigation kits were used for the valves. The kits include filters and backflow prevention devices. There were a total of 78 irrigation zones in the project; all were hardwired in. Trees are zoned separately from the smaller plants, so more water can be delivered.
Anderson points out that on any commercial job of this type, for it to be considered Water Wise by the city of Bend, it has to have a "smart" controller that can control multiple zones and utilizes current weather data for scheduling. This particular project required three controllers. The clock that was chosen is the WeatherTRAK Pro 2 system, commercial-grade, stainless steel units mounted on pedestals on-site.
A weed-prevention fabric was used to cover drip lines and
compost, with a river rock surface to be laid on top of that.
Anderson, who has a landscape design background, is certified by the Irrigation Association as a commercial irrigation designer. He says the three controllers will be operated manually for the first year to allow the city to set parameters for the local vegetation. That will get it established before the system is set to automatic. After that, the system will go on the WeatherTRAK satellite system utilizing local weather station data for daily input on scheduling.
Chris Koch, Springtime's construction production manager for this project, says that from the install end, a company must be up to date on the technology and methodology. He says that probably the most difficult part is in the programming of the WeatherTRAK clocks. Springtime construction crews take controller certification courses put on by the manufacturer, and crews have monthly meetings to go over issues with controllers or other aspects of irrigation jobs.
The sheer scale of such projects can be daunting, Koch says. This job finished out at about 5,000 man-hours, and required some logistical planning because of the PVC and drip line under the layered soil surface. The PVC supplies water to the drip line through a manifold at one end, with a 300-foot maximum run per line. This results in a grid pattern in a recycling system, which cuts down on friction in the lines and creates a uniform flow to all zones on the site. His crew on the Cooley Road project numbered from six to eight people once it got going, with one group going ahead with the irrigation installation and another following to plant vegetation. River rock was brought in on a conveyor truck to facilitate layering over the irrigation lines.
"I think the savings come from putting the water where it really needs to be," Koch says. Even though this type of system is expensive upfront, the ability of the system to deliver water precisely and uniformly is priceless. The mulching effect of the soil layers also conserves water, and the native plants do not need fertilizer. The ability of controllers to do daily scheduling based on actual evapotranspiration rates will further lower water bills.
Another design element of the Cooley Road project is the rain sensor that is placed on controllers as a backup. If a downpour comes, the sensor trips the controller and shuts it down for a day. The controller can be programmed on how much rain must be received before the system shuts down, and it starts up again when it determines that the plants again need water.
Low maintenance is another key component of a project design such as this. Koch points out that this system will be low-maintenance once it is fully operational. The system has built-in indicators to notify operators of trouble, for example, filters downstream from the valves have bubble indicators that turn from green to red when screen filters need to be cleaned. This allows city workers to quickly check them for clogging. In addition, there is a micro-spray nozzle in each zone that activates when the valve turns on, giving visual confirmation that the irrigation process is underway.
The WeatherTRAK controllers have alarms that signal when a valve becomes inoperable, and it can be located without a lot of labor. Trace line within the underground wiring allows a worker with a detector wand to locate a break in the line when a signal is sent through it, or to locate lines when utility or other type of digging is scheduled for the area. It is design elements like these that are required by the city of Bend in its specs that make it necessary for companies to be current on the methods in order to get the job.
"The city is doing a really good job on this, in my opinion," Koch says. He is also a water auditor, and he says that systems like this are efficient and easy to analyze. One drawback is that in case of a break in a water line or drip line, a worker will have to cut down through rock, fabric and compost layers to expose the line. On the other hand, the lines can be drained and blown out for the winter months to prevent freezing. Don Dale is a freelance writer and a frequent contributor. He resides in Altadena, Calif.
For more information on these companies, go to www.springtimeirrigation.com for information on the Bend, Ore., firm; www.weathertrak.com to look at the controllers used; and www.rainbird.com/drip to look at drip irrigation systems. For an extensive discussion of the elements of Water Wise landscaping, go to the OLCA site at www.oregonlandscape.org and click on the Water Wise icon.
Article as appeared in Landscape & Hardscape Construction, September 2008, page 16 - 21.