The Happy Gardener

The Newsletter Serving Residential Farmers of the world wide web


Say No to Runoff


         R unoff is the excess water that flows out of the sprinklers, into the street and sown the storm drain. It is the water that is not absorbed by the soil. Runoff occurs when sprinklers are left running too long. All sprinkler types will eventually produce runoff. One of the aspects of our Water Management Program is about controlling runoff.

How much water does the lawn and landscape need for its healthy survival? We determined how much water the soil absorbed by probing it with a soil coring tool. Probing the soil enabled us to measure the water depth of the surface area and below. Our test findings show that in June, July, August and September, the soils absorbed more water, therefore more water was needed to saturate it. However, in March, April, May and November, we observed that less water was needed to saturate the soil that the previous months. In most cases, the irrigation water can be turned off firing December, January, February because the soils are already saturated by the winter rains.

To determine the ideal running minute time for each sprinkler type, we ran separate tests using the various sprinkler types. We ran pop-ups, impacts, single and multiple spray rotaries, and drip until the point of runoff before turning them off. We found that more watering is needed for some sprinkler types while less time is needed for others. A pop-up, for example is designed to water an approximate 10 x 10 area. The pop-up puts out more water in a smaller areas so less watering time is needed In comparison, impacts or rotary sprinklers cover an approximately 20 x 20 area, so it covers a larger area with less water, therefore more watering time is needed. This information is vital for programming the irrigation clock.

Our Irrigation Schedules work extremely well in most yards and under most conditions because their built in flexibility allows you to make adjustments if your yard needs more or less watering. The schedules are designed to shut off the water at their approximate point of runoff.

Runoff is minimized by dividing the running time of the sprinklers into three separate intervals. For example, if you were running pop-ups for 30 minutes then you would divide that by three to come up with three, ten minute intervals, with each interval spaced at two hours apart. This two hour dryout periods allows the clay soils to absorb the water and achieve a deeper saturation in between the intervals. Similarly, when you divide your watering time in half, the recommended dryout period in between the two intervals is four hours.

Watering during the wee hours of the morning (1:00 A.M., 3:00 A.M., and 5:00 A.M.) is beneficial because it

  1. allows optimum water pressure
  2. keeps down humidity
  3. allows high traffic areas to dry out
  4. stops leaf burn
  5. slows down fungi and mold reproduction.

'Better Care Through Integrated Pest Management'


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