Highway deicing salt dynamic runoff to surface water and subsequent infiltration to groundwater during severe UK winters

Michael O. Rivett*, Mark O. Cuthbert, Richard Gamble, Lucy E. Connon, Andrew Pearson, Martin G. Shepley, John Davis

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    35 Citations (Scopus)
    182 Downloads (Pure)

    Abstract

    Dynamic impact to the water environment of deicing salt application at a major highway (motorway) interchange in the UK is quantitatively evaluated for two recent severe UK winters. The contaminant transport pathway studied allowed controls on dynamic highway runoff and storm-sewer discharge to a receiving stream and its subsequent leakage to an underlying sandstone aquifer, including possible contribution to long-term chloride increases in supply wells, to be evaluated. Logged stream electrical-conductivity (EC) to estimate chloride concentrations, stream flow, climate and motorway salt application data were used to assess salt fate. Stream loading was responsive to salt applications and climate variability influencing salt release. Chloride (via EC) was predicted to exceed the stream Environmental Quality Standard (250 mg/l) for 33% and 18% of the two winters. Maximum stream concentrations (3500 mg/l, 15% sea water salinity) were ascribed to salt-induced melting and drainage of highway snowfall without dilution from, still frozen, catchment water. Salt persistance on the highway under dry-cold conditions was inferred from stream observations of delayed salt removal. Streambed and stream-loss data demonstrated chloride infiltration could occur to the underlying aquifer with mild and severe winter stream leakage estimated to account for 21 to 54% respectively of the 70 t of increased chloride (over baseline) annually abstracted by supply wells. Deicing salt infiltration lateral to the highway alongside other urban/natural sources were inferred to contribute the shortfall. Challenges in quantifying chloride mass/fluxes (flow gauge accuracy at high flows, salt loading from other roads, weaker chloride-EC correlation at low concentrations), may be largely overcome by modest investment in enhanced data acquisition or minor approach modification. The increased understanding of deicing salt dynamic loading to the water environment obtained is relevant to improved groundwater resource management, highway salt application practice, surface-water - ecosystem management, and decision making on highway drainage to ground.

    Original languageEnglish
    Pages (from-to)324-338
    Number of pages15
    JournalScience of the Total Environment
    Volume565
    Early online date10 May 2016
    DOIs
    Publication statusPublished - 15 Sept 2016

    Keywords

    • Chloride
    • Deicing salt
    • Groundwater
    • Highway
    • Surface water
    • Urban
    • Winter

    ASJC Scopus subject areas

    • Environmental Chemistry
    • Pollution
    • Waste Management and Disposal
    • Environmental Engineering

    Fingerprint

    Dive into the research topics of 'Highway deicing salt dynamic runoff to surface water and subsequent infiltration to groundwater during severe UK winters'. Together they form a unique fingerprint.

    Cite this