UNC Not Potable Irrigation Final Report

• Project Type: General OWC
• Applicant: University of Northern Colorado
• Project Name: Non-Potable Irrigation System Usage and Cost Comparison
• Title: UNC Non-Potable Irrigation System Usage and Cost Comparison Final Report
• Date: 3/5/2001
• County: Weld
• Water Conservation - Doc Type: Final Report

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size of the Garden, 2) average amount of annual precipitation, and 3) type of selected
plants and their water requirements.
Water usage for the Denver Bronco's practice field and Nottingham Field was based on
past annual potable water use.

As part of the non-potable system, a separate water meter was installed specifically for
the Xeric Demonstration Garden in order to measure the exact water usage in gallons that
are used for irrigating Xeric Demonstration Gardens. In addition, a total of 46 water
gauges were systematically placed in 17 planting plant beds. Measurements for each
water gauge were recorded approximately once every 1O-l5 days, beginning on June 10,
2000 and ending September l6, 2000, for a total of eight sample periods.

RESULTS

Prior to the initial construction of Xeric Demonstration Gardens in 1998, projected water
usage for the Gardens was estimated to be approximately 5.4 million gallons per year.
Upon partial completion of the Gardens in 1998 and 1999 and total completion of the
Garden in 2000, actual annual water usage for Xeric Demonstration Gardens averaged
2.4, 2.2, and 2.6 million gallons per year respectively, representing a savings of
approximately 48% of the initial projected water usage. Projected water usage for the
next 10 years has been estimated to be approximately 2.4 million gallons per year.
Because most plants will be established by the end of growing season of 200 1 and
assuming normal precipitation rates, actual water usage for Xeric Demonstration Gardens
could be far less than anticipated. Refer to Table 1. For actual and projected water usage
and costs.

During the year 2000, water usage for Xeric Demonstration Gardens totaled
approximately 2.6 million gallons per year, the highest for any year. This was also the
year in which most of the plants were installed at Xeric Demonstration Gardens. In order
to ensure maximum success of the newly planted plants, the landscape contractor applied
above normal water rates for much of the growing season. In addition, the year 2000 was
the driest on record in over lO years, approximately 31 % below the 10 year normal and
23% below normal during the growing season from May through September (Table 2).
Therefore, in order to ensure survival for the majority of plants, above normal water rates
were applied during much of the growing season.

Exact water usage for the Denver Bronco's practice field and Nottingham Field could not
be determined with any certainty since neither of these fields have isolated water meters
installed on the water supply lines. However, it was determined, based on the area and
water requirements of the turf, water usage for the Denver Bronco's practice field and
Nottingham Field, would require approximately 20.6 and 10,1 million gallons per year
respectively. Projected water usage for both facilities is not expected to change
significantly within the next 10 years.

From 1996 through 1999, prior to the completion of the non-potable system UNC spent
approximately $200,00.00 on potable water for Xeric Demonstration Gardens, Denver

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