EXAMINING HOW BASIN CHARACTERISTICS MODULATE SIGNATURES OF RIVER SALINIZATION AT OVER 100 SITES

Long-term increases in salinization can disrupt ecosystem processes such as aquatic organismal development, replenishment of dissolved oxygen during periods of lake mixing, and biogeochemical cycling. In contrast, short-term fluxes in salinity from extreme events can also threaten ecosystem health due to the abrupt changes in environmental conditions and the sensitivity of many aquatic organisms to such swings. The speed, timing, and magnitude of salt transport through a watershed can be influenced by a variety of land uses, hydrologic features, and soil characteristics. In this study, we explored watershed characteristics that may exacerbate or buffer the impact of road salt on rivers in the northeast and midwest United States at 122 different sites. We focused on two salinization mechanisms contributing to in-situ dynamics observed in long-term records: "episodic salinization" resulting from the rapid flushing of salts after a winter storm, and "baseflow salinization" resulting from salt retention and release through subsurface flow paths. We found that under similar road salt application rates, sites exhibit different salinization dynamics due to differences in groundwater influence, hydrology, and land use. The results of this study add to the growing body of research characterizing the spatiotemporal extent and severity of freshwater salinization due to winter road salting, and gives us tools to identify at-risk rivers in order to improve management of roadways during winter months and better balance human safety with ecosystem health.

Primary Presenter: Lindsay Platt, University of Wisconsin-Madison (lrplatt@wisc.edu)

Authors:

Lindsay Platt, University of Wisconsin-Madison  (lrplatt@wisc.edu)

Hilary Dugan, University of Wisconsin-Madison  (hdugan@wisc.edu)