Rock slide in Fraser River, B.C., may hinder salmon passage

HOLY smokes...that is HUGE chunk of east toe...I thought the were done...that is awesome as east toe really narrowed it...nice work those on site.

This is not based on science or anything, but look at that area now after blast...common sense would say Chinook will be passing that fairly damn well! If someone has opinions on that love to hear it as like I said not a data based opinion just what I've seen MANY chinook pass by live.... excavating the rocks and debris at top of falls i bet would be huge if they have time
 
Something to think SG...Freshet has not even started. Fraser basin snowpack is 20 % above normal for the whole watershed, with some watersheds in the north Fraser being as much as 35% above normal. What you see now will be very very differant in 4 weeks. That area will be close to 40ft underwater if not more.

However, we have had a best case scenario in terms of freshet so far for work being done. Last year at this time freshet was fully underway. I am glad to see the east toe getting blown up, IMO it is the reason for a lot of the bottleneck of high water velocity in the area.

There is 100% Chinook moving through that area now, let’s hope they keep making it past.
 
Is there a webcam we can look at to see what it looks like as the water rises with these warm temperatures ?

hopefully it goes warm cool off warm cool off week by week or something to keep water levels not too insanely high.
 
There were acoustic arrays set up to monitor fish passage .. and I have not seen any updates on fish detection or passage. Did I miss an update regarding fish detection?
 
Based on a recent presentation by DFO (Gwil) there is still a TON of debris in the bottleneck that has not been able to be moved thus far. With time against us and as others mentioned an above avg snow pack things are not looking good for this coming year. DFO confirmed they expect big challenges with fish getting past big bar slide again for 2020. They have already contracted the salmon cannon by Whoosh to help with moving fish above the slide. They have trap and truck and a 'natural like' fish ladder/passage with boulders set up as well. I think everyone wishes for better news but that's the reality as of yesterday. I'll see if I can get my hands of the presentation by Gwil as it was quite well done and informative.
 
https://www.pac.dfo-mpo.gc.ca/pacif...lide-eboulement/bulletins/2020-04-17-eng.html

Big Bar landslide response information bulletin
Ongoing onsite operations
  • A video is available here. The blast is the last of the extensive in-channel work undertaken this season to improve fish passage. As with the previous blast of the East Toe in February, acoustic monitoring downstream of the slide did not detect any fish in the area before the detonation and no fish mortality was detected.

    In addition to the blasting, work continued on preparations for the installation of a pneumatic fish pump system. Preparatory work includes the construction of a concrete block fish ladder that will guide fish to the pump system, and the fabrication of hangers that will hold the fish passage tubes.

    The science behind a “nature-like” fishway
    The completion of the “nature-like” fishway on the west side of the Big Bar landslide marked a significant milestone for the project. The intent of a “nature-like” fishway is to mimic the natural river environment, in which fish swim past obstacles or through fast-flowing water. The fishway includes resting pools and creates passable rapids similar to what’s found in many river systems. These naturally-occurring features allow fish to move through a range of flow levels and maintain the critical energy reserves needed for migration.

    At Big Bar, although crews have successfully removed large amounts of slide debris from the channel that was identified for removal, the current may remain too strong for the fish during high water. The “nature-like” fishway will serve as a barrier against this heavy flow, which is amplified by the slide debris that remains underwater.

    Rock material that was removed from the river as part of the winter work was eventually used to build the fishway. Using heavy machinery, crews strategically placed clusters of boulders, about two metres in diameter, along the west bank of the slide site. These large rocks will disperse the current and slow the river velocity to create suitable migration conditions along the river edge.

    During freshet, currents can exceed eight metres per second and the boulders need to be large enough to withstand this pressure. The use of big boulders and the sloped nature of the fishway allow it to function in a wide range of water levels. The design also required specific elevations so early Sockeye and Chinook can benefit from the rock placement. The result will enable fish to pass during as much of the spring runoff as possible. The top of the “nature-like” fishway also consists of a four metre bench with strategically placed rocks, creating resting pools for fish during high water.

    Working ahead of freshet on difficult terrain and in challenging weather conditions required a flexible approach by the teams installing the fishway. Different scenarios were modeled with benches of varying widths, channel grades and slopes to determine the best solution at the slide site.

    Developing fish passage systems is a continually evolving science. The nature-like fishway is one of a series of mitigation measures being implemented to facilitate fish migration at Big Bar. The team will assess the instream conditions and monitor fish passage throughout the migration season to determine the fishway’s effectiveness. We look forward to showcasing the fishway in action in the coming months.
2020-04-17-c-eng.jpg

2020-04-17-a.jpg

A comparison of the East Toe before and after blasting that occurred on April 11, 2020. At higher flows, the river will be widened significantly.

2020-04-17-b.jpg


Construction continues on the creation of a concrete block fish ladder to guide fish into the pneumatic fish pump system.
 
The spring freshet appears to be upon us. They are evacuating areas of Cache Creek. Any idea what flows in the rock slide area are like?
 
Huge snow pack this year, so the water levels are highly likely to be bad unless we have an extremely cold summer.
 
I'll add to the negativity .. the combination of high water at Hells Gate and now at the Big Bar slide could prove too much for the early run sockeye and chinook stocks. The timing of this freshet will be crucial.
 
Nice that the warm weather slows down this week...hopefully that trend of melt then slow down melt then slow down continues! Should stabilize it rather than bamm all melting at once. Nimpkish River has levelled off the last two after raising a ton over the previous 5 days (my reference river despite distance from Fraser lol).

Thought Chinook went up in May-mid July too WMY?
 
SerengetiGuide said:
Nice that the warm weather slows down this week...hopefully that trend of melt then slow down melt then slow down continues! Should stabilize it rather than bamm all melting at once. Nimpkish River has levelled off the last two after raising a ton over the previous 5 days (my reference river despite distance from Fraser lol).

Thought Chinook went up in May-mid July too WMY?
Click to expand...

chinook should be in the area now id image
 
Hells gate info, looks all good

Fraser River Discharge at Hope
Critical Levels for Fish Passage through Fraser Canyon:

  • 7000 cms - Early signs of physiological stress evident
  • 8000 cms - Difficultly in migration delaying migration time.
  • 9000 cms - Barrier to migration through Hell's Gate.

Real-Time Hydrometric Data Graph for FRASER RIVER AT HOPE (08MF005) [BC]

upload_2020-4-22_14-3-38.png
 
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