Urbanization and water management control stream water quality along a mountain to plains transition

Water Resources Research
By: , and 



Urbanization can have substantial effects on water quality due to altered hydrology and introduction of constituents to water bodies. In arid and semi-arid environments, streams are further stressed by dewatering as a result of diversions. We conducted a high-resolution synoptic survey of two streams in Colorado, USA that transition abruptly from granitic/metamorphic forested mountains to sedimentary urbanized plains and are both highly managed for water supply, yet differ in degree of urbanization. A synoptic mass balance approach developed for mine drainage applications was adapted to elucidate effects of urbanization, geology, and diversions on stream chemistry during baseflow conditions. Urbanization was a more important driver of stream concentrations than geology. The urban area was a strong source of bromide, calcium, chloride, and manganese, while lanthanum and dissolved organic carbon were primarily sourced from the mountains. A majority of streamflow was removed by diversions near the mountains/plains interface. Groundwater accounted for 31% of the subsequent flow increase to the urbanized stream, and delivered at least 33% of chloride loading. Constituents that were primarily urban-derived (bromide, calcium, chloride, and manganese) were 2–3 times higher in the urban region due to diversions; without diversions, stream water quality would have largely retained characteristics of forested streams through the urban reach. This study provides insights into processes that affect water quality in highly managed streams of the semi-arid western USA.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Urbanization and water management control stream water quality along a mountain to plains transition
Series title Water Resources Research
DOI 10.1029/2023WR035633
Volume 60
Issue 2
Year Published 2024
Language English
Publisher American Geophysical Union
Contributing office(s) WMA - Earth System Processes Division
Description e2023WR035633, 19 p.
Country United States
State Colorado
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