Eliminating Run-off and Overspray

Run-off

Run-off occurs when water is applied too fast, or in too great an amount, to the soil. 

Most soils absorb water much slower than sprinkler systems apply the water to the landscape. It is best to use multiple, short duration watering times (cycles) with enough time between each cycle to allow the water to soak into the soil.

Sloping and poorly graded land can cause run-off. Terracing and shallow watering basins can help prevent run-off on sloped areas. Broad, shallow basins are generally better than deep, narrow ones; the wider the basin, the wider root area you can soak. 

Runoff causing expensive damage

to asphalt.

Once your sprinkler system has run through all the cycles, let the landscape rest and have a chance to completely absorb the water for at least a day before repeating the process.  Determining the length and frequency of watering for your landscape is a simple process. Visit the Plant List and note the hydrozone designation (level of water use and sun/shade necessary) for each of your particular plants. Now visit the Irrigation Guide.  Match the hydrozone designations to the watering schedules.  The Plant List and Irrigation Guide can be found on the Main Menu.

Overspray

Overspray is simply the water that lands beyond the planted or target area. When the overspray lands on sidewalks, drives and other hard surfaces it can, and does, empty into the streets and local waterways. Garden beds and irrigation systems should be designed to avoid overspray onto impervious surfaces.  Lawns should be held back from streets and driveways.  Overhead irrigation should not be used in planting areas directly adjacent to streets, driveways and waterways.

Irrigation overspray causing damage to fence.

Water running off the landscape will carry pesticides and fertilizers used on that landscape.  Once in the street, oil and trash may be added.  Even ‘clean’ water is chlorinated and can be deadly to aquatic life.

The hidden costs of overspray and run-off:

Irrigation overspray onto the sidewalk will

flow through the gutter, into the drain, and

pollute the ground water.