Wednesday, April 28, 2010

Tidal bore makes waves | - Tidal bore makes waves | By James Foster - Breaking News, New Brunswick, Canada

Deeper, wider river, open causeway, higher tides conspire to increase bore size -  By James Foster

Metro Moncton's missing-in-action tidal bore seems to be trying very hard to stage a comeback in the two weeks since the Petitcodiac River causeway gates were opened.

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The tidal bore slams into the edge of Hall’s Creek yesterday as it makes its way up the Petitcodiac River. The bore seems to be exhibiting renewed power since the causeway gates were opened this month.
Yesterday's bore was about two feet, or about two-thirds of a metre, in height, a big improvement from the ripple of water that in recent years marked the sorry state of what was once an international natural phenomenon.

To be sure, this is almost the time of the month when tides are at their strongest, and thus the bore is at its latter-day mightiest.
"But the fact that the gates are open does amplify that a little more," Petitcodiac Riverkeeper Tim Van Hinte contends.

Older residents of the area talk of tidal bores -- that twice-daily wave of water that turns the tide of the Petitcodiac River and fills it to the brim -- that were once many feet in height, at times. In the days after the Petitcodiac causeway was built in 1968, some bores have been barely discernible as the flow of the river was stifled, its depth and breadth vastly reduced, like the dimensions of the river itself.
The gates that hold back the river's waters at the causeway were opened on April 14 as the middle phase of a three-part initiative to replace a section of the causeway with a bridge.

The bore had become so impotent in recent decades that the City of Moncton's tourism efforts began downplaying the bore itself, instead guiding visitors' attention to the reversing of the tide and to how quickly the river fills after the tide turns. Fans of a free-running Petitcodiac hope the time soon comes when the tidal bore can return to a place of prominence on Moncton, Riverview and Dieppe's lists of things to see and do when visiting this area.

Yesterday's bore was more impressive than the norm.
At Château Moncton on east Main Street, a significant wave could be seen approaching from Dieppe. It passed with an audible roar and erosion was evident on the south bank of the river's muddy shore. That erosion is as intended, Van Hinte says.
"That's certainly where they do anticipate change on that side of the river," the riverkeeper says, referring to how the river is pushing out silt that choked much of the life out of it during the four decades that the flow of its once-powerful waters was decimated. The river is already noticeably wider at that point, though not dramatically so.

Chasing the bore upstream, perhaps the best view of all was from the Gunningsville Bridge.

Where on most sections of the river yesterday's bore stayed somewhat docile near the middle of the Petitcodiac, it was still a forceful wave on either side of the river, crashing up the river's banks. But from the bridge, one could watch a clear curl of water of a height that was far more eye-catching than in recent decades coming straight at you, passing directly underneath.
At Riverview's band stand, the section of the bore in the middle of the river again tended to peter out, but the water racing along each shoreline crashed its way upriver until finally becoming rather insignificant as it neared the causeway.

The causeway gates themselves also proved an interesting contrast. When the gates were first opened, the water on each side of the causeway at low tide was at dramatically different grades. In the two weeks since, the water escaping the headpond into the river has scoured the riverbed in the area of the gates, creating a set of rapids at low tide that grows in length daily and gives the impression the bed of the headpond is slowly making its way downward to the lower level of the river.
"Over time, that channel will start to erode away," Van Hinte says.
"It'll probably become a little flatter."

At low tide in the headpond, one can clearly see how the river is finding its natural meandering flow. At high tide, the headpond almost fills again, but with the chocolate waters of the river. The tide has been discernible on some days almost to Salisbury, though the waters are not brown that high up the river.
As well, some veteran river watchers believe the bore now arrives earlier than normal, though that could not be confirmed. To be sure you don't miss it, get there earlier than the scheduled time of the bore's arrival. An extra 10 minutes should ensure that you see the bore.

Don't rely on the city's bore-arrival clock at Bore Park, however. It's broken. Instead, go on the Internet and click on Tourism/Tidal Bore Schedule.pdf

What’s a bore?

It’s a wave, actually, the result of the record high tides of the Bay of Fundy that cause the water in Moncton’s Petitcodiac River to reverse direction and to raise with just one wave coming in from the bay.
In little more than an hour the river can go from a muddy river bottom at low tide to being filled to its banks at some 7.5 metres, or about 25 feet, in depth.

The Tidal Bore can be seen from many points in Metro Moncton, starting from various spots along the Dieppe riverside trail system to the south side of Champlain Street, near Hall’s Creek in Dieppe; in Moncton along the waterfront boardwalk or from Bore Park; or from Riverview’s riverside trail system.

The Gunningsville Bridge between downtown Moncton and Riverview offers excellent vantage points for pedestrians.

1 comment:

  1. Thanks for Sharing,interesting indeed.
    We have Tidal Bore in Sri-Aman Sarawak on Batang Lupar River.Go to my blog
    Have a nice day.


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