Chloride Monitoring Across Illinois, salt is commonly spread on roads during the winter to prevent the build-up of snow and ice. The salt dissolves in the melt water and travels into streams and groundwater, increasing the concentration of chloride (one of the main components in the salt) in local waterways. The large amounts of salt spread on roads in urban and suburban areas can lead to concentrations that are toxic to many fish and invertebrates. In the State of Illinois, 475 stream miles were listed as “impaired” in 2018 due to chloride. This means that these streams do not meet water quality standards. A recent study by RiverWatch Director Danelle Haake and several citizen scientists in the St. Louis area found that the winter concentrations of chloride were often unsafe for aquatic animals in watersheds where roads covered at least 5% of the land area. The Illinois RiverWatch Network is working to increase the amount of chloride data available in Illinois. You can explore the data that have been collected so far by visiting the Winter Chloride Watchers. If you are interested in participating in this project, reach out to the RiverWatch staff at riverwatch@lc.edu. Chloride Monitoring This winter project tracks road salt runoff. Read More Mussel Monitoring Learn to collect and identify these highly sensitive species. Read More Plastic Monitoring Are tiny plastic particles found in your stream? Read More Temperature Monitoring Borrow a datalogger to find out if your stream is unusually hot in the summer. Read More