Irrigation incentive study reduced
peak-period demand 26%
By Neal Klassen*,
City of Kelowna
Water Smart Coordinator
Participant average water use in 2001 with incentive compared to 2000 without
incentive.
In 1998, the City of Kelowna Water
Utility, in British Columbia, implemented
a user-pay rate based on
metered water consumption. The
average residential monthly water consumption
before that was 54 cubic metres.
Since then, average residential
monthly water consumption has
dropped to 44 cubic metres, or about
19%.
While this represented a significant
and welcome drop in overall water use,
a 2001 report estimated that $22 million
worth of infrastructure expansions
would be required over the next 20 years
to accommodate summer consumption.
Kelowna's semi-arid climate and generally
poor soil conditions cause summer
demand to skyrocket – particularly
in July. However, the report also noted
that, with a 16% reduction in water use
in July alone, the cost of infrastructure
would drop to just $5.8 million, due to
deferred and/or eliminated expansions.
So, in the summer of 2001, the City
of Kelowna Water Smart Water Efficiency
Program studied a series of incentives
designed to help customers reduce
water used for irrigation. Sixty
participants from the Crawford Estates
area (the neighborhood with the highest
average water consumption), were selected
at random to receive one of the
following incentives:
Education (home visits including
water audit irrigation system assessment);
Aeration/Ogogrow (core aeration and
top dressing of lawn with organic matter);
Rain sensor (to shut off automatic irrigation
systems in the event of rain);
or,
System improvements (an audit of irrigation
system and minor upgrades).
Each participant's summer 2001 water
consumption was compared to 2000
consumption levels over the same period.
Study results showed that participants
reduced their July water consumption
an average 26%.
Education
These customers received a home
water audit and an irrigation system assessment
by Water Smart staff. Particular
attention was paid to settings on irrigation
timers such as time of day, watering
times per zone, and number of watering
days per week. Advice was offered
on proper seasonal settings and,
where necessary, timers were adjusted
to deliver water in off-peak hours (early
morning) and for shorter periods.
These participants reduced their
water consumption by 27% in July.
Aeration/Ogogrow
Ogogrow is made up of composted
biosolids from Kelowna's wastewater
treatment facility. Each participant's
lawn received core aeration and a 1/2"
top dressing of Ogogrow mixed 50/50
with soil. The idea was to help customers
achieve a green lawn without the use
of high-nitrogen fertilizers and excessive
water consumption.
As the soil in Crawford Estates is a
mix of sand and gravel, the application
of Ogogrow increased the soil's nutrient
value and water-holding capacity.
Participants reduced their average
water use in July 2001 by 35% over July
2000.
Rain sensors
These participants had a "mini-click"
type rain sensor installed on irrigation
systems. Their average consumption
actually went up 15% in June (a rainy
month), then dropped 31% in July (a dry
month).
Inspections of the rain-sensing devices
and follow-up interviews with participants
revealed that there was not
enough heavy precipitation in June to
actually trigger the sensors. However,
participants were expecting the devices
to work, so they did not manually shut
off their systems during June rains when
they normally would have.
The dramatic drop in July water use
is the result of customer reaction when
they received notice that their June consumption
was above average. Therefore,
this 31% reduction can really be
attributed to education.
Automatic irrigation system
upgrades
Each participant received a professional
irrigation system assessment and
a list of improvements that could be
made to increase the efficiency of the
system. Participants were offered financial
incentives toward the upgrades, with
the option of paying for any additional
upgrades themselves.
Recommended system improvements
varied from home to home. In
some cases it was a matter of replacing
old sprinkler heads with more efficient
ones. In other cases, one zone was
changed to two zones to allow for proper
coverage. Changes in landscaping over
time also necessitated moving sprinklers
to more efficient locations. These participants
reduced their average water
consumption by 15% in July.
*Neal Klassen is manager of public education
programs for Neptune Technology
Group and coordinates the City of
Kelowna Water Smart program.
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