Yearly changes in the seasonal frequency and duration of short-term acid pulses in some Nova Scotia, Canada streams

The seasonal frequency and duration of low pH events at three sites located in southwestern Nova Scotia were analyzed using measured and synthetic dai ly pH data. The basins varied in size from 0.3 to 300 km(2) and were subjec t to frequent snowmelt events in winter and spring, as well as occasional r unoff events during summer and fall. Results showed that, in order to fill in missing data from periods where collection was interrupted, statistical approximations using discharge were not totally acceptable, as generated da ta consistently missed the extreme values measured. Despite a lack of total ly accurate event pH estimates for periods where daily data were missing, a nalysis showed that in this region, low pH episodes can occur year-round in cluding summer. The highest probabilities of low pH episodes nevertheless o ccurred in the winter and spring when snowmelts were frequent.