BOARD00164 ‎(2)‎

• Board Meeting Date: 5/22/2007
• Description: OWCDP Section - Presentation by the Center for Resource Conservation - Impacts and Findings of the Slow the Flow Colorado Irrigation Inspection Program
• Board Meetings - Doc Type: Memo

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consumption to landscape size, it is impossible to know if a participant is over-watering.
A common misconception is that if a property is using a large amount of water or has a
large landscape, the property is most likely over-watered. However, a trend was
observed during the course of this study that actually indicated the opposite. That is to
say that the larger properties tended to be less likely to be over-watered. Nonetheless,
even ifthese large properties are watering the correct amount given their landscape size
and the ET rate, more water than the city or utility wants to dedicate towards watering the
landscape may be used and this property would be categorized as a "high water user."

Therefore, it is possible that alternative initiatives such as limiting the amount of turf that
can exist in new landscapes, reducing the amount of turf in existing landscapes, and
implementing xeric alternatives to turfwould be helpful in water conservation measures.

Another finding observed during this analysis was the role that drought and mandatory
watering restrictions had on outdoor water use. The 2002 drought prompted many cities
along the Front Range to implement mandatory watering restrictions. As can be
expected, during 2002 water use was considerably lower than average for most
properties. However, a "roll-over affect" or "drought shadow" was observed in the year
following the drought in which mandatory watering restrictions were no longer in effect.
For example, in 2003, twQ-thirds of households analyzed were watering below the ET
rate. However, in 2004, that number dropped to only one-third of households watering
below the ET rate. In other words, a general trend was observed in which water use
tended to increase with each year after the drought. The irrigation inspection program
effectively reduced the water use of households watering above the ET rate in the years
following the drought. Though the severe restrictions did result in reduced water use, the
success of Slow the Flow Colroado provides the basis for efficiency as a means of water
conservation, rather then solely relying on severe restrictions to meet water use reduction
or conservation goals.

Another outcome to consider is that households that watered below ET prior to the
inspection tended to increase water use after the inspection. However, the trend was to
water closer to actual ET rates, without watering above ET rates. These customers still
received valuable information from the inspection that will allow the water to be used
most efficiently. Many of the households that were watering below ET prior to the
inspection, were allowing a portion ofthe landscape to die. This is not desirable as the
urban landscape has many environmental and community benefits, such as reducing the
"heat island" effect and filtering stormwater.

Problems seen in residential irrigation systems occurred in both contractor and
homeowner installed systems. In almost all cases maintenance problems contributed to
inefficient water use, or water waste. Improper design was also widely seen and posed a
much larger burden on the homeowner to finance and complete changes that would
improve upon efficiency. Ideally, landscape ordinances prior to installation would be
effective in addressing this problem.