DEPRESSION OF PH IN LAKES AND STREAMS IN CENTRAL ONTARIO DURING SNOWMELT

The snow pack that accumulted in central Ontario in the winter of 1977-78 had a pH of 4.0-4.5. The resultant runoff in the following spring in three intensively studied watersheds was characterized by a 2-13 fold increase in H+ content. Between 36 and 77% of the year's export of H+ from the watersheds occurred in April. Similar pH depressions were observed in almost all of 17 other streams that were less frequently sampled and in the littoral zones, surface waters, and outflows of five lakes.