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Tap water isotope ratios reflect urban water system structure and dynamics across a semiarid metropolitan area

NCJ Number
Water Resources Research Volume: 52 Issue: 8 Dated: 2016 Pages: 5891-5910
Date Published
20 pages
Since there is a pressing need to better understand connections between human populations, climate, water extraction, water use, and its impacts, the current study collected and analyzed stable isotopic ratios of more than 800 urban tap water samples in a series of semiannual water surveys (spring and fall, 2013-2015) across the Salt Lake Valley (SLV) of northern Utah.

Consistent with previous work, this study found that mean tap water had a lower 2H and 18O concentration than local precipitation, highlighting the importance of nearby montane winter precipitation as source water for the region; however, researchers observed strong and structured spatiotemporal variation in tap water isotopic compositions across the region, which they attribute to complex distribution systems, varying water management practices, and multiple sources used across the valley. Water from different sources was not used uniformly throughout the area and the study identified significant correlation between water source and demographic parameters, including population and income. Isotopic mass balance indicated significant inter-annual and intra-annual variability in water losses within the distribution network due to evaporation from surface water resources supplying the SLV. These results demonstrate the effectiveness of isotopes as an indicator of water management strategies and climate impacts within regional urban water systems, with potential utility for monitoring, regulation, forensic, and a range of water resource research. (publisher abstract modified)

Date Published: January 1, 2016