BOARD01420

• Board Meeting Date: 5/16/2006
• Description: OWCDP Section - Water Efficiency Grant Request from the Center for Resource Conservation
• Board Meetings - Doc Type: Memo

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Determine Soil Type and Root Depth: A soil sample is collected to determine
soil type and root depth. Soil type is categorized as clay, sand, loam or some
combination thereof. Soil type can affect the infiltration rate of water which
affects the frequency and duration that watering is needed. Root depth
measurements are also taken from a soil sample. System owners are informed that
healthy lawn roots should be a minimum of 6 inches deep. This is accomplished
by deep infrequent watering that greatly enhances a lawns ability to withstand
extreme temperatures and increased intervals between watering. Information on
amending clay soil to improve water- holding capacity is also provided during the
audit.

Provide an appropriate watering schedule: Using data collected during the
audit, an appropriate watering schedule is developed for the customer for their
current irrigation system. Watering intervals change throughout the season
because the water requirements change for plants as the seasons progress.
Through analysis of historic evapotranspiration (ET) data, average irrigation
pressure, and soil type, it has been determined that turf should be watered every
four days in May, every three days in June, July and August, every six days in
September and every ten days in October or until the end of the irrigation season.
The duration of watering should be kept the same, with only the intervals between
watering changing.

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For areas with clay soil, cycling during watering is recommended.
The term cycling refers to running sprinklers repeatedly within an irrigation
interval to allow for better water absorption. Cycling allows roots to grow more
deeply into the soil profile; increases drought tolerance and disease resistance.

Example of a watering schedule for a spray zone with clay soil and a PR of
.9" thr.

Month Timeslweek Cvcles Minutes Total Total
Minutes per Minutes per
waterina week
May 1.5 3 12 36 54
June 2 3 12 36 72
July 2 3 12 36 72
August 2 3 12 36 72
September 1 3 12 36 36

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Take Pressure Readings: Pressure readings are taken on spray zones, and when
possible rotor zones. The design of rotor heads makes it difficult to accurately
check the pressure. The proper pressure for fixed heads is between 20 and 30 PSI;
proper pressure for rotor heads is between 50 and 70 PSI. The proper pressure
will vary between brand names.

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