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Eliminating Runoff and Overspray

 

Water Waste is unnecessary and illegal

Article X of the California Constitution specifies that the right to use water is limited and does not extend to waste or unreasonable method of use.  Pasadena adopted a water waste ordinance in July 2009 that prohibits 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.

 

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Runoff causing expensive damage

to asphalt.

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Runoff transporting pollutants to local creeks and ocean via storm drains

 

 

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.

 

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Irrigation overspray causing damage to fence.

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Run-off violates Pasadena’s Water Waste Ordinance

 

 

 

 

Water running off the landscape will carry pesticides and fertilizers used on that landscape.  Once in the street, runoff may also pick up oil, trash, sediment and other pollutants.  Also drained swimming pool water is chlorinated and can be deadly to aquatic life.

 

Unlike sewers, storm drains are not connected to treatment plants. Water and pollution that runs off of streets and land flows directly into rivers, creeks, sloughs and the ocean without being filtered or treated. In inland areas, storm drain runoff is sometimes directed into open spaces where it percolates into the ground.

 

Water pollution is a serious problem because it causes changes in the biological, physical and chemical characteristics of a water body. Some attributes of water that are affected by pollution are pH, acidity, dissolved oxygen content, nutrient or sediment load and the presence or absence of pathogens. Changes in these attributes caused by pollution can harm aquatic life, create unpleasant odors and, in the case of pathogens, may cause disease in humans that come into contact with the water.

 

The hidden costs of overspray and run-off:

•Paying for water that is not needed, or used, in the garden.
•Accelerated deterioration of asphalt drives and parking areas.
•Damage to fences, siding, patios, walks and other garden structures.
•Reducing water quality at creeks and beaches.
•Harming aquatic life.
•Causing disease in humans that come into contact with polluted waters.
•Creek clean up and watershed restoration projects.

 

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Irrigation overspray onto the sidewalk will

flow through the gutter, into the drain, and

pollute the ground water.

 

Here are six strategies for mitigating or eliminating run-off and overspray:

1.If your landscape is composed of individual plants, such as shrubs, rather than continuous groundcover like turf; convert your spray system to drip irrigation.
2.Re-landscape with individual plants (one-gallon size or larger) and convert the spray system to drip irrigation.
3.Replace all the plant material with a permeable, non-living groundcover such as gravel, rock mulch or decomposed granite that will not require irrigation.
4.Install a buffer strip of permeable, non-living groundcover such as gravel, rock mulch or decomposed granite between the plant material and the hardscape and move the sprinkler heads inward to the edge of the planting bed. (See drawing below) Because of the possibility of wind and misadjustment, this solution is not fool-proof.

5.Install a subsurface irrigation system such as ECS or Wick. Note that these systems are relatively costly.
6.Aerate your lawn.  Over time, soil compacts and forms an impenetrable surface.  Aeration breaks up the hard surface so the water can soak in to give your lawn more oxygen, nutrients and water.  And you'll see less water running down the street.  For lawns, use a manual coring aerator (available at home improvement stores) or rent a machine – either one is easy to use.  Water 1 to 2 days before you plan to aerate to moisten the soil so it doesn't compact around the holes.  Make 2 to 3 passes over each area, with holes about 3-inches apart.  Don’t aerate your planter beds, this will disturb the healthy and beneficial ecosystem of earth worms, fungus and bacteria that are vital to healthy soil and happy plants.