Downstream: The Forgotten Mend

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Photo by Louis Cahill

Photo by Louis Cahill

By Devin Olsen

I’ve been fortunate to fish with a lot of anglers fishing a lot of styles over 20+ years of fly angling.

One of the things that has separated the great ones from the good-to-mediocre ones is their understanding and execution of mending. While some techniques like European nymphing are effective in part because they don’t require mending (see for more information), most fly fishing methods require correct and efficient mending to be consistently successful at catching fish. “So what is a mend and why do you need to do it?” you ask? Here is my quick two-part answer:

  1. Simply put, mending is the repositioning of fly line on the water. It can be done during the drift or with aerial mends during the casting stroke (i.e. reach casting).
  2. It is usually done to achieve a dead/imitative drift when fishing nymphs or dry flies or to manipulate the speed and direction of the swing when fishing streamers or wet flies.

If that wasn’t enough to make things clear, let me expound a bit. If you look down on a river, the current has all sorts of different speeds from one bank to the other. These differences are created by obstructions and the shape of the channel which block, direct, and change the velocity of currents. Because of friction, these currents grab and hold fly lines and compete with each other for their plastic coated prize. In simplest terms, when a fly line is cast across two or more speeds of current, faster currents will move the fly line downstream at a quicker pace than slower currents. “Duh, but what does that have to do with my fly,” you say? The answer depends upon the method you are fishing.

In the simplest general terms again, fly fishing techniques either try to present a fly with the speed of the current that it is in (AKA a dead drift) or in a manner suggesting the fly is swimming at a speed and/or direction contrary to the current (AKA a swung fly).

In the dead drift scenario with a fly line across multiple current speeds, the body of the fly line will either be sped up or slowed down by the current relative to the tip of the fly line and your fly. Eventually this pulls the fly faster or slower than the current it resides in. This condition is known as drag and can look like your fly or strike indicator is waterskiing across the water. Drag typically results in few fish being caught if you are aiming for a dead drift. In the swung fly scenario (basically intentional drag), the differing current speeds will affect how fast your fly moves downstream and laterally across the stream. In either of these situations, most anglers are taught on their first day of fishing about the need for mending upstream. This is typically because they are fishing across faster currents to slower currents where fish are saving a bit of energy out of the main current. However, I’ve noticed a lot over the last few years that a lot of anglers (even seasoned ones) have forgotten the need for the downstream mend. I hope the following slides will illustrate the issue with both the dead drift and swung fly presentation.

For both scenarios, our master angler stick figure “Bill” will demonstrate the reasoning behind the downstream mend.

In the first scenario, Bill is casting quartering upstream with either a dry fly or suspension/strike indicator nymph rig. He is standing on an inside corner where there is slower water and is casting out into the river where the current is much quicker.


As Bill’s drift begins, the faster current out in the river begins to move the far half of his fly line quickly downstream while the slow current at his feet is moving the near side of his fly line much more slowly downstream. The result is that the currents begin fighting each other for their respective ends of the fly line and the end where Bill’s fly is begins to move slower than the current it is and track across the river; a textbook example of drag.


Bill-2Since Bill is a master angler, he knows he can correct the situation by making a downstream mend. He accomplishes the mend through a smooth three step process:

  1. Bill points his rod quartering back upstream
  2. Bill lifts his rod to reduce the amount of line stuck in the water
  3. Bill turns his reel downstream and uses his thumb to make an underpowered roll cast which repositions his slack line downstream

Bill-3After Bill makes his mend, he temporarily eliminates the opposing current forces on the ends of his line and his drift can continue a bit longer. Depending upon the specific currents, Bill may have to repeat this sequence several times to get the longest drift possible.


Let me provide a real life example of the need for a downstream mend. Not too long ago I was fishing with another angler (I’m going to be very vague here to avoid ego bruising). We were floating from a raft and he was fishing a suspension/indicator nymph rig while I was Euro nymphing. Though I expected to do a little bit better than said angler, my catch was outpacing him even more than I thought it should. When I started paying closer attention to how he was fishing, I noticed he was making repeated upstream mends. The problem was that he was fishing into faster water than where we were positioned and his indicator was repeatedly doing little waterskiing moves upstream. I was surprised to see this since he is not new to the sport by any means and spends a lot of time on the water but, like a lot of anglers, his muscle memory had programmed him to make upstream mends regardless of the situation that was inducing drag. Because of our relationship, I didn’t want to step on his toes too much by turning into his guide. However, in a couple of spots, I quietly suggested that he should make a downstream mend instead and he was rewarded with fish.

Bill-4Let’s move to Bill’s second scenario. He is now swinging a wet fly or streamer on a downstream presentation. He makes a quartering downstream cast to start his swing. He again is faced with faster water in the middle of the river toward the end of his fly line and slower water by his feet.


Bill-5As Bill’s swing starts, his fly and the end of his fly line moves quickly downstream. The latter half of his fly line ends up pointing downstream while the line that is closer to him has not moved much from its original cast trajectory.


Bill-6If Bill is fishing in cold water and needs to slow down the lateral movement of his swing, then he may choose to leave the line and swing to do what it will. However, Bill knows that many flies fish better when their profile is shown to the fish instead of just their tail and the lateral movement of a fly can often entice a more direct predatory response than a fly that is facing upstream and moving away from the fish. As a result, Bill makes a downstream mend similar to the first scenario but he directs most of the slack directly downstream instead of toward the fly. In turn the mend forces the fly to take a more lateral track across the river until it straightens out below Bill.


HeroLet me finish off with another real world personal example of Bill’s second scenario. After coming back from the World Fly Fishing Championships last September, I dedicated much of the Autumn to spey fishing for steelhead and only brought the Euro nymphing rods out for a few trout trips. Despite a dismal steelhead return, I had a couple of very good days and found fish when catch rates from the creel reports had been very low. Many of the steelhead I caught were early in the swing or after a downstream mend. In these circumstances, the fly was tracking laterally across the river showing a perpendicular or quartering profile to the fish. Furthermore, I had plenty of instances where I made a swing through an area that I thought should result in a fish but I received no response. In several of those instances, I tried mending downstream or stopped mending upstream when I went back through the area and I caught a steelhead. Those recent experiences, and numerous others from many years on the water, have taught and reminded me that the downstream mend is not to be forgotten. So next time you are out on the water, analyze the situation and see if the approach calls for a downstream mend instead of the upstream mend that is so deeply programmed into most of us.

Devin Olsen
Gink & Gasoline
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5 thoughts on “Downstream: The Forgotten Mend

  1. Great reminder, Louis. I don’t fish as much as I want to (who does? ;-> ), but at only 10-12 trips a year and about 2/3rds of that on moving water, it’s easy to forget the downstream mend. Fortunately, I have helpful guides who gently remind me…

  2. Great info as usual Devon. It seems to me that you should let the river tell you what kind of mend you need. Isn’t it funny the little habits we get into that keep us from catching fish!
    Thanks again,

  3. Great post, Devin! I will be applying your ideas to vary the presentation swinging Atlantic Salmon flies this fall. Thanks for providing a thorough description of mending and breaking it all down – the visuals really help.

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