Headwater lake chemistry during the spring freshet in North-Central Ontario

✍ Scribed by J. R. M. Kelso; C. K. Minns; J. H. Lipsit; D. S. Jeffries

• Publisher: Springer Netherlands
• Year: 1986
• Tongue: English
• Weight: 672 KB
• Volume: 29
• Category: Article
• ISSN: 0049-6979
• DOI: 10.1007/bf00158757

✦ Synopsis

From data on 30 headwater lakes in north-central Ontario we found that, during the spring snow melt of 1981, all lakes underwent serious declines in alkalinity. Generally, SO42-, alkalinity, Ca 2+ and Mg 2 + concentrations were reduced by runoff and rain then recovered to intermediate levels after the major inputs declined. As expected, a range in responses was evident with lower alkalinity systems showing the greatest changes. The observed changes, however, were consistent with acid loading having depleted alkalinity.

In calculating an input-output budget for each lake, we found that changes in C1 , Na ÷ , and K ÷ were consistent with atmospheric inputs being the major source as the difference between the expected input and the actual contribution from rain and snow had a mean near zero. There appears to be a significant, ~ 45 %, watershed source of sulphate that we hypothesize is from dry deposition occurring prior to snowfall and is eluted with the melting process. With refinements to a mass balance approach explaining the watershed source of SO42-and A1, we feel it is possible to predict springtime lake changes given a few chemical and simple morphometric variables.