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Multiple land use activities drive riverine salinization in a large, semi‐arid river basin in western Canada
Author(s) -
Kerr Jason G.
Publication year - 2017
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10498
Subject(s) - soil salinity , arid , environmental science , hydrology (agriculture) , watershed , salinity , soil water , structural basin , urbanization , drainage basin , ecosystem , ecology , geography , geology , oceanography , soil science , paleontology , geotechnical engineering , cartography , machine learning , computer science , biology
Salinization is increasingly recognized as a global issue. However, the relative importance of different drivers across a broad range of ions and ecosystems is not well understood. This study examined spatial and temporal dynamics in riverine salinity (conductivity, Ca 2+ , Mg 2+ , Na + , K + ,SO 4 2 −, Cl − andHCO 3 −) in the South Saskatchewan River Basin (SSRB), a semi‐arid, mixed land use watershed in Alberta, Canada. A significant temporal increase ( p < 0.05) in the concentration of one or more ions was observed at all 12 study sites. While all ions exhibited a significant increase in concentration over time, the rate of change was generally highest for Cl − (≈ 1.4–3.0% yr −1 ). The observed increase in riverine Cl − loading downstream of a large urban center (≈ 1700 tonnes yr −1 ) was attributed to increasing inputs from road salt (≈ 1800 tonnes yr −1 ) and to a lesser extent municipal wastewater (≈ 400 tonnes yr −1 ). For most other salts, spatial variation was driven not by urbanization but by the proportion of salt affected soils and/or cropland. A distinct Na 2 SO 4 signal was observed at stations draining salt affected soils which strengthened over time at 7/12 sites indicating temporal trends in Na + andSO 4 2 −have been driven largely by soil processes. A strong relationship between cropland and salt chemistry across the basin suggests agricultural activities have also contributed to observed trends. Therefore, in regions with similar climatic and anthropogenic characteristics to the SSRB, multiple stressors are likely to be operating and as such, these systems may be at particular risk from salinization.