It seems like the last few summers have been drier and hotter than we’re used to. People are saying this is the “new normal”. Unfortunately, the new normal is still a long ways off. For at least the next 50 years climate scientists are predicting constant change.
The Pacific Climate Impacts Consortium (PCIC) is a not-for-profit organization based at the University of Victoria that, among other things, provides climate change predictions for the Pacific and Yukon regions. Their work is to “provide regional climate stakeholders with the information they need to develop plans for reducing the risks associated with climate variability and change.”
Their predictions for the Comox Valley during the period 2010-2039 include a 3% increase in annual rainfall compared to the 1961 to 1990 Base Period. But there’s a catch: most of this additional rainfall will be in the fall and winter. The summers are predicted to have 10% LESS rainfall. And the decrease in rainfall will be accompanied by an annual temperature increase of between 0.4% and 1.3%.
For the period 2040-2069 the annual increase in rainfall is predicted to be 6% but, again, the summer change is projected to be 17% LESS than the Base Period.
It may be tempting to assume that the additional rainfall will be stored in our aquifers and allow us to get through the drier summers. But that may not be the case. How much of that rainfall will be absorbed into the ground instead of rushing down the creeks to join the Salish Sea? We don’t know. One thing we do know is that the changing climate is going to be a stress on our water systems. For those of us concerned with the quantity and quality of our drinking water, conservation needs to be a large part of our “new normal”.
( Go to the Pacific Climate site to see more. )
After our hot, smoky summer, it might be a good time to take stock of our water situation. The trend seems to be towards longer, drier summers and there were reports this year of lower than normal well levels. We really don’t have enough data to draw conclusions but we are concerned: a dropping water table at the end of summer could be a warning sign. And one of the concerns for a coastal aquifer such as ours is saltwater intrusion. Here is how the BC website on Salt Water Intrusion describes it:
Saltwater intrusion occurs when saline (salty) water is drawn into a freshwater aquifer. Saltwater intrusion can affect one well, or multiple wells in an aquifer, making the water unpotable.
And the site goes on to advise:
Know the risks: Be aware of areas that are at risk of saltwater intrusion and educate property owners, site managers or water system operators that their well or locale could be affected.
Wells closest to the coast are at the highest risk. Many Fanny Bay wells are within metres of the ocean and some are actually drilled to depths BELOW sea level. It’s the weight of the water in the hills above us, the hydrostatic pressure, that keeps the saline boundary from creeping in. If the local water table drops too far we could start seeing saline intrusion.
There are many factors that can increase the risk of salt water intrusion. Increased population is one, as it results in increased water consumption. The population of Fanny Bay increased by 10% in the period between 2011 and 2016. Climate change is another. Climate models for our area predict increased rainfall but wetter winters might not be enough to keep our water table from dropping during longer summer droughts.
While we continue our efforts to learn more about our water supply it certainly won’t hurt for us all to begin developing good water conservation habits.