Water runoff occurs when excess water from irrigation, rainstorms or inefficient watering schedules build up in yards and landscaping and spill over onto the sidewalk or street.
The heavy clay soils found in the Southwest are very fertile but have very small pore spaces and are slow to accept water. Infiltration rates are well below one-tenth an inch per hour across most of the metro Phoenix area. On slopes or compacted heavy clay soils, water is generally applied faster than it can soak into the soil, resulting in water being wasted as it runs off the site, over the sidewalk into the street, down the gutter and into the storm drain.
Preventing Runoff: Cycle and Soak
To avoid run-off on the grass or sloped areas of your landscape, you may need to schedule several shorter water cycles in the same day, allowing about 30 minutes in-between for the water to soak in. This is called "cycle and soak" and is easily programmed into your irrigation timer.
This method of irrigation applies water slowly so the soil actually absorbs all that is applied. Instead of running each lawn sprinkler zone for 10 - 15 minutes each, run each zone only the amount of time that the soil can absorb the water (which means it's not running off onto the sidewalk or street).
Here's a typical cycle and soak schedule for lawns:
- Water for 3 different start times
- Water for 4 minutes each cycle
- Wait at least 30 minutes in between cycles
- Water 2 or 3 times per week in summer
The goal is to allow the water soak down to 6 – 8 inches into the soil. This depth is ideal for lawn areas and promotes the growth of deep roots. Roots that grow deep into the soil will create grass that is stronger, healthier and better able to withstand the brutal heat of summer. Because watering deeply keeps moisture in the root zone longer you won’t need to water as often. On the other hand, shallow watering produces soil that dries out quickly and creates grass and root growth that is weaker and less dense allowing competition form weeds.
How do you know how deeply the water is soaking in?
Use a probe like a long screwdriver and push it into the soil in several places. It will slide easily through wet soil but will be nearly impossible to push through dry clay.
Other Ways to Conserve Water
Smart Water Controllers
Smart controllers automatically adjust watering times and frequencies throughout the year with minimal human intervention. This technology has proven to help cut annual outdoor water use by 30% or more, reducing watering bills and helping to conserve our precious water supply.
Learn how you can conserve water and save money with a smart water controller.
Chandler offers more than 20 free Water-Wise Workshops over the course of the year in both spring and fall. The workshops cover topics ranging from landscape care and design, vegetable gardening, outdoor watering, smart controllers, irrigation design, controller programming and Water 101.
You can register for workshops online to reserve your spot.