Bulletin Board
1999 Annual Report "Wiser Water Use in Salt Lake City." A report to the Central Utah Water Conservancy District on Grant No.764.
Earl K. Jackson, Utah State University Extension in Salt Lake County
November 24, 1999
Background
Water experts believe about half of the water applied to lawns in Salt Lake City is wasted over the landscape year. This is a concern since the lawns in Salt Lake City are watered using culinary water. The Wiser Water Use Education Program was funded in late 1995 by the Central Utah Water Conservancy District (CUP Credit Program) to a partnership of Utah State University Extension in Salt Lake County, the Great Salt Lake Audubon Society and Salt Lake City Public Utilities. Water audits and training workshops were conducted during 1996.
The primary goal of the Wiser Water Use Education Program was to work with and educate many of the largest water users receiving culinary water from Salt Lake City Public Utilities. During 1995, we identified parks, schools, golf courses and churches were managers and/or maintenance personnel requested irrigation system water audits and demonstrations to train people on the principles of proper scheduling and system performance.
The secondary goal of the Wiser Water Use Education Program was the education of homeowners demonstrating how they could save water by irrigating their landscapes more efficiently and reduce lawn size by Xeriscape (water-wise) type landscapes. In Salt Lake City, a lush, green lawn historically requires a 27-inch high column of water distributed evenly over the lawn periodically during the growing season. With a 50% efficient system, the water requirement is for a column of water 54 inches high. This is equal to 1,466,316 gallons to water one acre of lawn through the season.
Water Conservation Impacks from the Grant Large Water Users
1997 Water Savings
Using the 1996 monthly landscape water use as the base year to calculate water savings, we documented a substantial amount of water saved by the 69 accounts monitored. These accounts used 395,135 hundred cubic feet (ccf) for outdoor water use during 1996. During 1997, the total outdoor water use was reduced by 63.416 ccf to a total of 331,416 ccf. This equates to a water savings of 16.1%. The average large water user account reduced water use by 923 ccf for the year following training.
1998 Water Savings
These same 69 accounts reduced their total landscape water use to 28.7% saving another 113,329 ccf during the 1998 landscape year. The total water saved over a two year period by these 69 parks, schools and churches was 177,048 hundred cubic feet. At the current rate of $1.17 per ccf, this volume of water saved is $207,146 or an average of $3,002 saved per account. The 177,048 ccf saved is equal to 132,431,904 gallons of water which would fill the Utah State University football stadium with a column of water 406 feet high!
1999 Water Savings
The data has not been documented yet for the 1999 landscape year but will be included in our next annual report.
Residential Water Users
1997 Water Savings
During the summer of 1996, 48 residents educated in the Wiser Water Use Program used a total of 8,008 ccf on their landscapes during this base year. After receiving help in irrigation scheduling, xeriscape principles and water system efficiency, they used only 6, 540 ccf during 1997. The data indicates these residents reduced their outdoor use by 18%. On the average, they each saved nearly 31 ccf during 1997 over the 1996 water use.
1998 Water Savings
During the 1998 landscape year, these same 48 residents reduced their water use to 6,131 ccf thus reducing water use by 23% over their 1996 level.
1999 Water Savings
The data has not been documented yet for the 1999 landscape year and will be included in our next annual report.
The Average Resident
Based on residential water audits, the average precipitation rate for residential sites is over 1.1 inches/hour. This is equivalent to a very heavy rainstorm and if the sprinklers remain on for more than 15 to 20 minutes, the soil cannot absorb the water fast enough and much of the water runs off. The scheduling for each irrigation system needs to be checked however because the range of water put out by the residential pop-up heads is incredible, ranging from 0.11 to 2.85 inches/hour. The distribution uniformity ranged from 23% to 87% with an average of 51% for all sites. The variation in water pressure at the sprinkler head was surprisingly high ranging from a low pressure of 25 psi to a high of 110 psi. Adjustment to scheduling by changing the timers for the season remains a major problem with home owners.
We reached the same conclusion as we did from our work with the large water users; by watering properly with a 70% efficient system, homeowners could save between 10% and 20% on their summer water bill and use only about half their current culinary irrigation water over the landscape year. They would also end up with a healthier lawn.