AWWA SOURCES55577

Increasing water demand due to landscape irrigation in many urbanizing areas in the West is straining supplies and forcing water purveyors to implement water conservation measures without knowing who should be conserving and how much water is potentially conservable. This study used aerial false color imagery to determine irrigated landscaped area for a section of Layton, Utah and estimated the amount of potentially conservable water in urban landscapes. False color images of a subsample area consisting of commercial and residential areas were collected in late summer 1998. A geographic information systems parcel-boundary layer was overlaid on the images and the landscaped area was determined by counting the number of vegetation pixels within each parcel. Water billing data averaged over 1996-98 was then normalized to depth units with the calculated landscaped areas and then compared to estimated water needs derived from local evapotranspiration rates. Residential landscaped area determined from aerial image analysis was verified with ground measurements of area, and landscaped area correlated well with total lot size. Commercial water users, particularly retail establishments, applied water in excess of estimated needs, 70% versus 14% for subsample of the residential water users. Excess irrigation was highest in midsummer through early fall for both residential and commercial landscapes. The high excess irrigation, particularly among retail businesses, was likely due to high expectations for an attractive landscape and the prevalence of automated systems that allowed unmonitored irrigation that was not changed in response to lower plant water needs during late season. The lower excess irrigation among the residential water users was probably due to older housing with fewer automated systems and lowered landscape appearance expectations. In this study, the potential water savings for approximately 300 businesses in the study would require similar savings from 6000 residential customers when extrapolated beyond the study area. Includes table, figure.

Product Details

Edition:

Vol. - No.

Published:

01/01/2002

Number of Pages:

5

File Size:

1 file , 400 KB