Baseline readings of the streams in the Little Falls watershed showed high to chronic levels in three locations. Both the Little Falls and Willett Branches had levels above 200 ppm in our December baseline reading. The Willett Branch reading was 290 ppm, which is above the tolerance threshold for fresh water organisms.
Baseline readings are taken before the winter storm season starts to give us an idea of how impaired the streams are before winter road salting begins. We expect that the numbers will be low as there is no salt run-off to pollute the creek. When you see high numbers in baseline readings, it can be an indication that the ground water was polluted from winter salting in previous years and is now making its way into the creek. This trend has been noted in urban streams especially and is thought to be from increased in salt use during the winter. A national study of salt levels in creeks concluded that high baseline levels were not from an increase in pavement, but from an increase in rate of salt application. https://www.usgs.gov/centers/upper-midwest-water-science-center/science/evaluating-chloride-trends-due-road-salt-use-and
Click HERE to learn about the problems road salt causes and how you can reduce the risk to the environment and your drinking water, while still keeping roads and sidewalks safe.
The LFWA Salt Watch program is in our second year, with citizen scientists taking readings at 8 locations around the watershed. We test the Little Falls Branch in 5 locations, the Willett Branch near the Bethesda Pool, the Glenmont Tributary and the Minnehaha Branch in Glen Echo. Our volunteers do baseline readings once a month on the second weekend and before and after snow events. The program is part of an effort by the Izaak Walton League to map salt levels nation-wide.
The results of all readings can be found on our website at www.LFWA.org/salt-testing
