Casting downstream is not generally my first instinct. But when I do, I have a good reason for it. Yes, the default mode for fly fishing is to cast upstream. It provides greater control of the drift, and a lot of the action happens as your fly drifts right in front of you. It also keeps you behind the trout you’re trying to catch. This prevents them from seeing you and fleeing to safety.
However, here are three times when it makes sense to cast your fly downstream:
1. You are fishing streamers in deep runs
Of course, you can cast a streamer upstream, let it drift down the current, and then strip it in back upstream once it swings across the current at the end of your drift.
But in deeper runs, I like to get above them and make my cast downstream.
I aim for the tail end of the pool or run and give my streamer time to sink. Then, I strip it back through the pool. This creates the effect of something swimming rather than drifting — and that is what you want with Woolly Buggers or Dalai Lamas or other streamers. I feel like I have better control that if I cast upstream, let my fly drift through the run, and then retrieve it. Often, the area above the run is too shallow to be fishable. So why bother?
I’ve fished a lot of runs from above in the fall on the Gallatin River near Bozeman, Montana. It’s been deadly on brown trout. Dave, my podcast partner, and I did this effectively too last fall on Willow Creek in Montana’s Gallatin Valley.
Even though when you cast your fly downstream, it puts you above the trout, they are less likely to see you when the run your fishing is deep. Of course, you can always find ways to stay hidden by crouching down or hiding behind some brush on the bank.
2. You are trying to cast a dry fly in a tight spot
Suppose you’re fishing upstream (with the current coming towards you), and you come to a run that is tight against the bank on which you are standing. You might be able to wade out into the stream or river to get a better angle. But on some streams or rivers, you cannot do this without spooking fish. It’s time to figure out how to cast your fly downstream.
I think of a run in the Yellowstone River that hugs a rock cliff for about two-hundred yards. This run is too deep to wade. It’s flows so tight against the bank (with little curve to the river) that it creates an awkward cast for a right-handed caster (which most of us are). The best solution is to fish it from above and cast your fly downstream.
Sometimes, the current can be a factor.
I think of particular runs where I could minimize drag (the current dragging my fly through the run) by standing above it (casting downstream) than by approaching it from below (casting upstream).
3. You are dealing with wind and shadows
This may seem obvious, but it’s worth pointing out: it’s harder to cast with the wind in your face than with the wind at your back. If the wind is strong enough (and it has not convinced you to quit), cast your fly downstream just so you can get the wind at your back — particularly if you need distance on your cast.
Later or earlier in the day, the shadows are longer. So the sun can be an issue. If the sun is behind you casting long shadows when you’re trying to cast upstream, then go above the run and cast downstream so your shadow doesn’t spook the fish.
Sometimes, one cast is the best shot you have at catching a fish from a particular run. Treat the cast like a golfer treats a putt on the green. Analyze the situation and figure out your approach. In a few cases, it might make more sense to cast downstream.
For more information on how and when to cast your fly downstream, listen to our podcast on Casting Upstream or Downstream.