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August 21, 2017 6:41 am

Fraser Freshet Happening Earlier Says Study

Thursday, January 28, 2016 @ 3:59 AM

SockeyeSalmon4Prince George, B.C.- A new  study by researchers at UNBC warns of  dangers to salmon  migration and  future  drought along the Fraser River all because of climate change.

The report,  “Impacts of a Rapidly Declining Snowpack on Streamflow Timing in Canada’s Fraser River Basin”  analyzed data  from 1949 to 2006.  What they  discovered is that warmer temperatures have changed the kind of precipitation,  resulting in  reduced snowpacks and more rain which  mean the  spring melt is happening earlier.

UNBC  Professor of Environmental Science, Dr.Stephen Dery, is one of the co-authors of the report which has been  published by the Nature Publishing Group’s journal Scientific Reports.

Dr. Dery says  the total  amount of precipitation remains  about the same, but  the mix of snow and  rain to that total  has shifted “Over the  period of study,  the contribution of snow to the  Fraser River flow  has declined  between  20 to 25%” says  Dr. Dery.  “So we have less snow to melt and it’s melting  earlier,  so that  melt water reaches the Fraser River  earlier than it used to in the past, so the  spring freshet has advanced  by about 10 days.”

Earlier peak flows  could  spell lower than normal flows and  warmer than normal water temperatures by the time the salmon are migrating up the Fraser River.

Lower  water levels  can  translate into  warmer water temperatures. “20 degrees is really the critical  temperature for salmon” says  Dr.Dery, if the water is  above 20 degrees C,  fish  may become susceptible to a  disease  called columnaris,  and  can become confused about  where they are supposed to go.  “Certainly for a couple of summers in the Nechako River, water levels have reached that level if not  above, so certainly not  good conditions for the salmon in that system.”

Then there’s the potential for drought. “Lower flows  definitely are an indication of dry conditions.  Certainly for the past couple of summers here in Prince George, we have seen  these very dry summers.  Just looking into  the future, we believe this  is going to be a more frequent occurrence in the Fraser River Basin.”

“Unfortunately, I think conditions may be exacerbated in the future”  says Dr. Dery, ” I guess one option is  that we increase releases from the Nechako reservoir during that critical (salmon migration)  period  in the summer.”

Dery says it’s not the end of the world “We will still see some summers  with  above normal  precipitation,   but it’s certainly a trend we are seeing now based on our results.”

Dery says some “adaptation strategies” may have to be considered, such as  increased water restrictions or  closures of fishing seasons “The Fraser  River is still a very large river, so it’s not going to go bone dry, so there will still be lots of water in there,  even in the dry  summers,  but certainly  we may have to consider  such options.”

Comments

“”Prince George, B.C.- A new study by researchers at UNBC warns of dangers to salmon migration and future drought along the Fraser River all because of climate change”.
Just what is meant by the words “climate change” is this study denying there was such a thing as climate change before 1949? With all the academics involved you would think there could be a definition of “climate change”
“Certainly for a couple of summers in the Nechako River, water levels have reached that level if not above, so certainly not good conditions for the salmon in that system.”
Could reduced flows from the Kenny dam have any effect those summers, no mention of that in the study at all, how come? There is mention of releasing more water into the river during low years, well what about before the dam, ignored. Maybe if they had a predetermined outcome going into this study that would have skewed the results?
In fact the study makes no mention of the impoundment behind the Kenny dam at all, why is that? I am sure that impoundment should have some effect on the flows past Hope. The study also states land use effects were also not taken into account, say what, just what kind of a study is this. A predetermined outcome I suspect. Irrigation, the removal of water for irrigation seems to be also ignored.
Lots of weasel words used, such “I think”, “we believe”, “could” in other words send more money, more study needed.
Wonder what the flows where like in the early 1900’s, medieval warm period, Roman warm period, Holocene maximum, maybe their models could tell them. In other words is the results of this short period of study unprecedented?
As for warming we are still recovering from the little ice age.
Now back to “climate change” now with out sticking their necks out and using the words man caused warming of which they are inferring, can these scientists tell us how much of this warming is anthropogenic or natural? Heck there is no reproducible, verifiable science that shows how much mans minuscule contribution to greenhouse gases affect climate if any at all. Scientists don’t even have the natural side figured out.
If this is what passes for science these days, oh my.

Seamutt, I believe the study concentrated on the Fraser River basin, but your points on the Nechako River are valid, especially as they pertain to the Fraser downstream of P.G.
What I got from this study is that less of the precipitation is falling as snow, implying that temperatures must have been higher than usual during the period of study, ergo: change of climate.
Maybe not permanent, but definitely changing i.e. warmer than it used to be.
Not much disputing that.
metalman.

It just seem strange that the flows of the catchment area behind the dam seem to be ignored in the study along with other land use issues. I just don’t see how reasons can be given for reduced flow past Hope while ignoring the above.

I just get suspicious when I see the term climate change used in general with out definitions. It seems to me they tip toe around coming right out and saying man caused warming which is the money maker.

Other factors that impact the flow of water in the Fraser basin are clear cuts, and the beetle killed forests. Both accumulate more snow during the winter months, and delay the runoff from these areas. So we have a longer runoff period with cold water. Seems to me this should have been considered in the study.

I hear you, as an important tributary to the Fraser, the Nechako and its tributaries should probably have been included in the study.
But should they then have included the Thompson as well?

The Kenney Dam and related debacle on the Cheslatta were a travesty for the Nechako River, certainly the vastly reduced flow caused a deleterious effect on returning salmon.

But in the 50’s and 60’s we were all about opening up the Province to development, in the interest of increasing our population and thereby building the tax base. It must have seemed like a good idea at the time to hand over natural resources to Alcan.
I don’t think that back then enough people appreciated what sort of effect damming up a river would have, much less allowing the doling out of water to the remains of the river based on the industrial needs would have on the environment as a whole.
metalman.

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