If you squint really hard, you can just barely make out the first tiny trickle of water melting off the snow on the mountains towering over the Fraser Valley. Okay, maybe not. But if the last few days of balmy weather are to be trusted, the spring freshet can’t be far off.
I’m back in British Columbia to sample the Fraser River during the most dynamic time of year: the spring freshet. This is the most exciting period when the river shifts from its quiet, winter-time state to a rushing torrent of water and mud. As the ground warms and the water level rises, vast stores of sediment, nutrients, and organic matter are flushed off the land and into streams across the basin, drastically changing the chemistry of the water. This is the most important time to sample a river, because the composition of many chemical properties is so different from the rest of the year, and the amount of material exported dwarfs that of the summer, fall, and winter.
Our sampling campaign during the 2011 freshet captured a snapshot of this period all over the basin, in tributaries from the Rocky Mountains to the floodplain. This year, I’m sitting in one spot – our time series location in Fort Langley, near the river mouth – and collecting samples every day to make sure I don’t miss the chemical pulse I expect to see right as the water level begins to rise.
So for now, I’m just settling into my sampling routine and getting to know my new instrumentation. Will this year’s freshet be as big as last year’s – the biggest in 40 years? Only time will tell… -Britta Voss