Water Conservation Tips for Apartment Properties: Cycle and Soak Irrigation Systems
While this summer hasn’t been the typical scorcher in Texas and the Southwest, continued drought conditions are forcing water conservationists to look deeper into the calendar to extend lawn watering restrictions. Because the next three months look dryer than normal across the region and other parts of the U.S., several cities and municipalities are considering extending current restrictions or even tightening to once-a-week watering into the fall.
That means that as property owners irrigate within narrow watering windows to keep their landscapes healthy, every drop will count. Wasted water runoff will not only draw attention but essentially starve landscapes of what is becoming a precious resource.
Properties need to take to heart that paint company’s popular slogan, “No runs, no drips, no errors.” A cycle and soak approach to irrigation will get the job done.
Understanding Cycle and Soak Irrigation and Evapotranspiration
The cycle and soak irrigation program significantly reduces, and in some cases eliminates, run off from sprinklers that over saturate an area of the landscape. Sprinkler zones are programmed through a standard or evapotranspiration-based irrigation programmer to cycle – the system alternately runs and stops throughout the cycle to allow water to better soak into the targeted area. For example, the system may run for four minutes, stop for 60 minutes, run again for four minutes and so on. With the stop-start pattern, the area gets the full benefit of irrigation while minimizing runoff down the hill, on sidewalks, onto curbs and into gutters.
Your mother probably practiced a very elementary approach to the cycle and soak method when she hand-watered rose bushes. When water began to puddle around the base of the bush, she twisted the nozzle and shut off the supply from the hose. Once the water soaked in, she applied a little more water and continued the cycle until the ground was good and wet.
A recent study at Texas A&M University that documented the effectiveness of cycling and soaking was a little more revealing. The Aggie research team determined a zone needed 26 minutes of watering, so on went the sprinklers – for 26 minutes. When the water shut off, researchers noted that the area “drained” for 30 minutes to release all the water that hadn’t been absorbed into the soil.
The conclusion? Just because a zone may need 20 minutes of watering based on its evapotranspiration rate doesn’t mean that it’s getting quality irrigation by leaving the system on for the entire session. Watering a little bit at a time is much more effective and eco-friendly.
Choosing Soil for Cycle and Soak Irrigation
To maximize the cycle and soak approach, soil composition and slope of the area must be taken into consideration. Also, a little homework needs to be done.
The type of soil affects the infiltration rate of the area. A real sandy soil is going to absorb water much faster than a hard clay soil. Sandy soil has looser particles that are more porous, enabling a higher flow rate. On the other end of the spectrum, clay soils have smaller particles that are more compacting, restricting the rate of absorption. There are several variations of loams and clays in between, depending upon region, and each should be taken into consideration when determining how much water should be applied and how quickly.
Water on a slope naturally will run off, thereby necessitating a closer watch on how much water is spread across the area. Simply, flat ground accepts water quicker than a slope. Just as the water is being pulled down into the soil by gravity, it’s also being pulled down the hill by gravity. Also, the makeup of the slope will affect the rate of absorption. A fully sodded slope will take in the water more than a bare, non-grassy slope.
Field Test for Cycle and Soak Success
There are calculations – based on soil type, slope and so forth based on evapotranspiration rates – that will determine appropriate cycle and soak times. But sometimes the best way to find out is a simple field test. To start, turn on the zone, set a stop watch and watch for the point where water starts to sheet off the surface or puddle, or where water flows into areas that it’s not supposed to flow instead of soaking into the ground. Shut off the system and let the water absorb. Note the time and repeat the on-off process until the desired total watering time is achieved. With most soil compositions, sticking with no more than a five-minute cycle is effective.
Most commercial grade and smart irrigation systems have cycle and soak settings, so it’s just a matter of inputting data gathered from the field test to set up the program.
Certainly, a property’s actual conditions will determine the proper cycle and soak rate. None are the same. But one thing is constant: a landscape irrigated with the cycle and soak method will get the full benefit of watering. And you’ll just feel good about conserving water.
Video Description: Dr. Richard White, a Texas A&M University turf-grass specialist, discusses how homeowners can save water and money by using a cycle and soak method of irrigating their lawn.
Image Source: iStockphoto