Geostatistical Modelling of High Spatial Resolution Stream Chloride Concentration Patterns in Rural, Urbanizing, and Urban Watersheds
Abstract
The application of road salt to impervious surfaces to maintain road safety results in long-term increasing chloride concentrations in streams, lakes, and groundwater aquifers, placing aquatic ecosystems at risk. In Canada, the environmental risk management strategy for road salt focuses on best practices for storage, spreading, and snow disposal. Organizations that manage road salt are responsible for identifying salt vulnerable areas (areas of the environment that may be particularly sensitive to road salts). To date, only watershed-scale correlative models relating outlet chloride concentrations to average landscape and flow characteristics have been used to identify salt vulnerable areas. The goal of this study was to investigate the influence of key landscape characteristics on stream chloride patterns at the reach scale. We conducted longitudinal surveys of stream chloride concentrations across seasons and flow states for three watersheds (rural, urbanizing, urban) in Southern Ontario. These data were used to build Spatial Stream Network models for each watershed and flow state. Lane-length density, rural land cover, and a surficial permeability index were tested as potential drivers of chloride patterns. Lane-length density was a significant predictor only in the rural and urbanizing watersheds, suggesting that other variables may be more important to consider for salt vulnerable area identification in urban areas, such as spatial variability in road salt application rates and the complexity of sewer-stream connections. Results also show that spatial structure in stream chloride concentrations was lost under higher flow conditions, which has important implications for when data should be collected to map salt vulnerable areas.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H42G..04O
- Keywords:
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- 1848 Monitoring networks;
- HYDROLOGY;
- 1871 Surface water quality;
- HYDROLOGY;
- 1879 Watershed;
- HYDROLOGY;
- 1880 Water management;
- HYDROLOGY