What's Causing The Flood On The Nechako River?

Thursday, December 13, 2007 04:00 AM

View of the Nechako River, looking upstream , shows flooding on the Pulpmill Road area on the right, and River Road on the left (photo Opinion250 staff)

Prince George, B.C. - Questions are being raised as to what impact increased flows into the Nechako River may have had in creating an ice jam near the confluence of the Nechako and Fraser Rivers in Prince George .

On November 7^th Alcan (Rio Tinto) announced that maintenance work would be carried out on the Skins Lake spillway. The discharge from the spillway was reduced to 15 cubic meters per second (579 cubic feet) that flow remained for the period until November 19^th when the repairs were completed and the flow was increased to 85cms ( 3000 cubic feet per second )

It normally takes about 10 to 12 days for water being released from the Skins Lake Spillway to reach Prince George. It normally reaches Vanderhoof in 5 to 7 days.

Ten days after the flow was increased, Prince George was plunged into a deep freeze that didn't show any signs of breaking until December 10th.

Opinion250 contacted several hydrologists from Canada and the USA to get their feelings on how increased flow might impact the river in Prince George.

One hydrologist says the river system in this region entered the fall season with a higher than average flow coming from the Lakes and rivers in the area. While the sharp increase in flows into the Nechako would have an effect on the overall flow of the river, it was his opinion that it would take a combination of weather and flow to produce the problem that we have today.

An American hydrologist echoed the remarks of his Canadian counterpart; he did however add this comment. "Any time that you introduce five times the flow into a river system during a period of ice building, you can produce a problem. Frazzle ice forms, usually in areas of fast stream movement with some sort of water course impediments. That ice would be carried downstream under an increased flow, but that again would depend on the other sources of the river flow." Could introducing this extra water have an affect on the river? “Yes “.

Meantime, Lyle Larson of the Ministry of the Environment in Prince George was asked if Alcan’s rate of flow would create the problem, “I would say it is not “I don’t think it is causing any excessive issues. "

Larson says a number of options have been examined, including using heavy equipment to break up the ice "But there is an awful lot of ice there, and it just wouldn’t work".

Can you dynamite the ice on the river? Our experts say there are some very selective cases in which you can do that, but they say it usually does little to help the situation.

The last time the Nechako River flooded during the winter was in 1997 when Alcan released a significant amount of water into the Nechako just before the area fell into a deep cold snap.

The City of Prince George is to release an update of the flood situation at 8:00 this morning.

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Posted on Thursday, December 13, 2007 04:00 AM in News by 250 News

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Comments

Posted by: Wileycoyote on December 13 2007 7:08 AM

I knew all along it would be something to do with alcan releasing sooo much water. But guess who gets to foot the bill once again.........

Posted by: giterdun on December 13 2007 8:12 AM

LARSON SAY..."HEAVY EQUIPMENT OR DYNAMITE WON'T WORK". HE IS 100% CORRECT IF YOU DON'T EVEN TRY. GET SOMEONE WITH EQUIPMENT AND ROAD BUILDING EXPERIENCE DOWN THERE. ICE WILL BE GONE. I THINK WE NEED A NEW FLOOD BOSS, NOT A BUREAUCRAT WHO APPEARS TO BE ON ALCANS SIDE.

Posted by: northman on December 13 2007 8:34 AM

You gotter giterdun. Someone with road building and maitenece experince would be able to get the ice moving. Once you open up a peice of the main channel things start moving pretty quickly.

Posted by: Andyfreeze on December 13 2007 8:48 AM

Right on all!
Sitting back watching the ice build up is plain stupid!!
DO SOMETHING!
I do not believe that nothing can be to help the situation even in a small way.
Another case of taking the easy way out waiting for mother nature to fix the problem!
In case they haven't realized it yet,winter is just getting started!
Equipment,dynamite,whatever it takes,just do it.
Actually,there is enough hot air on council to probably do the job!

Posted by: owl on December 13 2007 10:02 AM

I think there is enough information there from two separate hydrologists that tells me that while one may not be able to win a suit against Alcan for lack of due diligence in the way and timing they released the water, there is certainly enough there to get a more formal opinion in writing with some recommendations of how it could have been handled to reduce the risk of an ice jamb.

With that in hand, an operating directive should be able to be given to Alcan which should reduce the future likelihood of Alcan being a likely contributor of causing such an event.

That being said, the more important contributors to the damages are two-fold.

One, people and industry being too close to the edge of a river which can overflow due to annual spring runoffs, increased annual precipitation, and local ice jams.

Two, the city having made little effort to structurally improve the situation so that such more or less natural events will not impact the rivers edge and low lying lands to such an extent. This is done all over the world and has been done so for thousands of years using a combination of engineering solutions � adjacent land build-up, dikes, channel dredging, back water valves in storm outfalls, pumping systems, etc. etc. So far, the City has done little on the prevention side.

Maybe now that it is not only residential streets involved, but also industry, we can get some serious money from the province to assist with those industries move to higher ground by putting them in a new heavy industrial park outside the �bowl�. That would get rid of several problems all for the same investment � less industrial traffic in that area, less air pollution in that area, a new industrial park in a more environmentally correct area, removal of industry from prime riverfront.

I am sure Alcan will even donate some $ for a good cause.

Posted by: giterdun on December 13 2007 10:50 AM

OWL... DON'T HOLD YOUR BREATH WAITING FOR ALCAN TO DONATE. WE'RE STILL WAITING FOR PROMISES OF PROJECTS AND EXPANSIONS FROM YEARS AGO. JUST ASK THE PEOPLE FROM VANDERHOOF. ALCAN IS TOTALLY FOR ALCAN AND FULL OF SMOKE AND MIRRIORS. THE ONLY GOOD CAUSE ALCAN KNOWS IS PUTTING MONEY IN THEIR COFFERS...PERIOD.

Posted by: YamaDooPolCat on December 13 2007 11:38 AM

I was hired by BC Hydro to fly them around the town of Peace River during the annual ice jams and flooding. BC Hydro spent lots of money, but nothing moves ice until it's ready. Figure out how puny our efforts are compared to what weight and force we are dealing with.

I'm sure BC Hydro plowed enough dynamite into the peace river ice to start a good size war, to no effect. Probably killed lots of fish in the process.

After years of study and millions of dollars in research, the conclusion reached was people should not build where they can be flooded out by ice jams.

It was an interesting three years though. I still remember how good the Baby Back Ribs was at the local pub we ate at.

Posted by: slider71 on December 13 2007 4:45 PM

mmmmmmm...baby back ribs!

Posted by: Palopu on December 13 2007 7:18 PM

The name of the game is to keep the ice moving and this is done by doing the things that Owl mentioned.

Insofar as dynamiting goes. It depends on who's doing it, and where. They have cleared ice jams at the confluence of the Fraser and Nechako rivers in the past with dynamite, however I suspect that those people who knew how to do it are all dead now.