Kootenay hasn't produced big fish in years. You will get rainbows but nothing like the big one above. Even the top biologists are working on a 12 year plan to restore the kokanee populations. Once they have recovered they believe the rainbows will bounce back. But they are only guessing at best.
Here's the results from the Nelson Police derby last October.
2017 Nelson Police Dept. Derby winners;
Rainbow Aggregate:
Bob Garding 13 1/2 lbs
Rose Marie (Boat) 12 1/2 lbs
Dustin London 12 1/2 lbs
Bull Trout
Eileen Garding 4 lbs 15 oz
Peter Defeo 4 lbs 8 oz
John Henke 4 lbs 7 oz
I know Woodbury calls it a dolly derby. But they are wrong. They are Bull trout. Not dolly varden.
This is what I would try if I was going to go to the derby. Apex lures, in silver, green, or white. Or a combination of those colours. J-plug lures like Tomic, or Lyman style lures. White, silver, green or yellow. Or a combination of those colours. Spoons like Gibbs Delta G Force, Bon Chovi, or Irish cream. I'd also try any of the Gibbs Delta Skinny "G" spoons. Some guys use a silver dodger or a flasher like a dodger and a white hoochie behind it. I would also have some bucktails to run on the surface, in case the plugs and spoons aren't working. I like blue/white or purple and pink ones. Some people call the purple/pink ones Kootenay Lake specials. I'll post a few of the bucktails that I tie and a few lures that I like.
Good luck, and tight lines.