The Coquihalla is a sorry story of how the development of the hwy and the transmountain pipeline ruined the river forever.
I remember going there as a kid and camping on the banks of the river.Beautiful spot. We would fish, catching rainbow trout.My friends 2 uncles would fish everyday and would catch trout and when lucky Steelhead.
The development and paving of the Coq was rushed because it had to be open for EXPO 86 .This included the rerouting of the river in several places. This and the placement of the pipeline for Transmountain severely changed the river forever . They are maps available online, if you examine them, Transmountain actually owns a large swath of land beside the river, in some cases, displacing its path. This was back in the day when the environment was not really a big issue.
Unfortunately this changed the river forever, along with the increased vehicle traffic and access.What was once a great river to fish close to the LM has all but become devoid of fish.The river has become catch and release , to sustain the small population that still survives.
My reading of the regs is that its only open for summer flyfishing.