OBSERVATION: Carly Blashyn (primary observer) observed that the seasonal lake level peak associated with freshet/spring runoff is now experiencing shifts in timing. The primary observer has based her observation on past seasonal exposure to Shuswap Lake (June 1999 - August 2006) and recent year-round exposure (June 2015 to present). These observations have been supported by local colleagues, family and friends in the area (secondary observers), and by trends indicated through the Shuswap Lake Watch program (www.shuswaplakewatch.com).
BACKGROUND: In the past, the average lake level (peak) has occurred between June and July. This generally places low water stages between September and April. However, with lake level peaks occurring earlier in the year, lake level lows are also changing in response.
POTENTIAL IMPACTS: In 2015 the maximum peak occurred in late May/early June and the resulting early low lake levels (starting in mid-August) had serious environmental and economic consequences. In terms of economics, many local businesses founded on tourism became limited by low water levels (http://www.cbc.ca/news/canada/kamloops/low-water-levels-in-shuswap-lake-cause-business-concerns-1.3209766). From an environmental perspective, low lake levels have serious implications on spawning fish populations--for example those in the Adams River which already face declines in stock. (http://www.saobserver.net/news/337754991.html). Lake levels are already starting to rise for the 2016 calendar year and may reach peak levels by early May; following the 2015 trend this indicates that lake level lows may begin as early as late July.
CONSULT:
At a local scale, lake level trends are correlated to changing climate weather data. Peak levels are lower (less maximum runoff) as supported by both temperature and precipitation/ snow pack trends (Environment Canada, Shuswap Lake Watershed snow pillow data). Earlier lake level drops are leading to increased surface water temperatures towards the end of the growing season, which is leading to additional impacts including algal blooms (http://www.saobserver.net/news/305082771.html) and decreased water quality.
