With some places in the watershed receiving nearly an inch of rainfall earlier this week, and high temperatures well above average for the last week or so, VLAWMO's lakes have been completely thawed out. Within recent memory, this is the earliest the lakes have been free of ice this soon in the new year, and with the thawing of the lakes comes the beginning of the monitoring season.
While regular lake and stream monitoring will not start until the beginning of May, ice-off is when preliminary chloride samples are taken from the 6 regular monitoring locations along Lambert Creek. Road salt is the primary culprit of high chloride levels in Minnesota water bodies, as it used in the winter on surfaces for it's effectiveness of improving safety and driving conditions on icy and snowy roads. VLAWMO takes chloride samples just as lakes are done thawing, and when the snowpack has melted. This is done in attempt to record peak chloride levels from road salt that has entered as runoff into water bodies from its use during the winter.
The winter of 2015-2016 was very mild, translating to less than normal salt usage. Chloride is a persistent chemical that often remains in water bodies, unless there is an inlet/outlet where the residing water can be flushed from the body, bringing in water with lower chloride levels. Lambert Creek is almost always flowing and being flushed during the regular monitoring months of May through September with rain water.
The 6 samples collected from the Creek were brought to Ramsey County for lab analysis, and results will be relayed to VLAWMO soon. It will be interesting to see if there is a difference in last year's creek samples' chloride levels compared to the samples taken in 2016, to see if the correlation between lower winter road salt usage and creek chloride levels after lake ice-off.