Do you see how small these mats are... We are talking about 30-40 meters long..... They are there to prevent fish from spawning in the very SMALL location so that none of the eggs are harmed... Also they are not cutting a trench through the river... They bore under it...
Blown way out of proportion
I think you have been misinformed about the rivers crossings on this project. Here is a list of the crossings in that area that going to be "trenchless", bore under it as you say.
"Construction of the Trans Mountain Expansion Project in the North Thompson region includes approximately 275 km of pipeline and four pump stations. Construction is expected to take place between September 2017 and November 2019. The majority of the construction will follow conventional pipeline construction techniques, with trenchless techniques being used for the
North Thompson River, Blue River, Raft River, Clearwater River and Mann Creek crossings. In these locations, a horizontal directional drill will be used to minimize impacts and disruption to these areas."
https://www.transmountain.com/north-thompson
Here are the crossings from the news report.
"Stephen said in an interview from Chilliwack on Monday that the affected streams in B.C. are located in the Valemount area, and include
Swift Creek, Camp Creek, Serpentine Creek, Chappell Creek, and three crossings of Albreda River."
http://vancouver.24hrs.ca/2017/10/1...untain-biologist-over-unauthorized-river-work
So you see that contrary to your understanding the fact is those crossing will be trenched just like the video that was posted depicts. The real question is how much damage are they going to make and how long will it take those crossing to recover.
This is important as the news report mentions that these are spawning beds for salmon that are key to some of the regulations that our local recreation anglers are concerned about.
"Stephen asserts in the letter that "this apparently unproven spawning deterrent method" was applied to eight streams, one in Alberta and seven in B.C., that Trans Mountain considered to have a high “fish habitat sensitivity rating” in documents filed with the National Energy Board.
Among the fish species with conservation concerns found in those rivers are bull trout, chinook salmon, and
Interior Fraser River coho salmon."
http://vancouver.24hrs.ca/2017/10/1...untain-biologist-over-unauthorized-river-work
The reason why we have not had wild coho retention for the last 20+ years are because of our impacts on IFR coho. Now this pipeline is impacting the spawning beds of these coho and that is what is troubling.