A tiny beetle is going to cost us more for water treatment.
First, though, it will infest mature pine trees, kill them with a fungus it carries, and when the trees are logged, or crash and rot, there will be a series of changes in domestic watersheds that could adversely affect our quality of water.
That’s the picture painted by Kelowna hydrologist Don Dobson of Dobson Engineering, talking about the mountain pine beetle’s impacts on water quantity and quality, and the implications for water purveyors.
Loss of shading with the loss of mature forest will result in faster spring runoff and heavier flows, which will impact water quality downstream with increased sedimentation, he warned.
Instead of snow melting first at the valley bottom, then gradually higher and higher up in the watershed each spring, it’s expected that would be condensed, with valley bottom snow melting at the same time as it begins to melt at higher elevations.
Creek beds which can be deeply scoured during one-in-50-year flood events, could have that happen once in every 10 years instead, causing an increase in nutrient loads as riparian areas are washed away; more pathogens, and then more operational and treatment costs for domestic water.
With loss of mature trees there will be earlier spring runoff, earlier demand for stored water, so there could be supply issues for local utilities.
If dead trees are not salvaged logged, the forest fire risk will be severe, and once fire has gone through the soil loses its organic content and becomes the texture of flour.
The first heavy rains carry these loads into streams and water intakes.
For decades into the future, watersheds will be recovering from the mountain pine beetle infestation.
Unfortunately, Dobson said beetle-infested wood quality in this part of the interior remains marketable for a shorter time than that from the Cariboo because of drier conditions here.
Coupled with the current crisis in global lumber markets, companies are not finding it economical to log beetle-infested stands of timber.
Left standing, dead pine forested watersheds could take 60 years to recover, while if they’re logged and replanted, their recovery time could be 30 years, he said.
It varies in different watersheds, but Dobson believes the increased risk of forest fire risk near populated areas is our biggest enemy.
However, both water quality and quantity, and the timing of the annual snowmelt could all adversely impact water purveyors and their customers.