They can be long or short, deep or shallow, and usually, merge with other types of trout water. Riffles will often settle into a run and runs may transform into deeper pools with a slower current. While a run will have other elements such as a riffle at the head and maybe a pocket, it's probably best to think of it as a relatively long piece of water that is unbroken by any major rapids or shallow shoals that completely separate it from the rest of the river. A run isn't exactly one precise type of water but is generally not so choppy as a riffle has a bit more current than a pool. Runs can be perhaps 20-30 yards long in a stream but might be a mile long in a big river. Inside that run, there will be hot spots of fish activity as well as dead zones, but there is very little to keep fish from moving around in this long piece of water and choosing different lies depending upon their motivation to feed.
The current is flowing about the same speed all the way across this wide river. Ian has positioned the drift boat over a relatively shallow weed bed where fish are less likely to be. This positioning allowed the angler in the front of the boat to hook up with a fish in a deep slot that was completely unaware of the boat's presence.
Regardless, of the differences between different runs in rivers and streams, they are among the most common areas to find trout.
The variety of features makes them a hotbed of activity because different types of insects will all thrive in the different habitats. One set of insects will inhabit the swifter water at the head of the run, others will prefer the deeper water, and the edges will probably be favored by yet other bugs. This variety allows trout to feed or rest under a variety of conditions and gives them more food over a greater duration. Unfortunately, this variation in features can make it tricky for anglers to read the water and any fly fisher should have a plan when it comes time to fish. The most important thing anyone can do before casting a fly on the water is to stop and look around for a bit.
One of the main characteristics of a run is that the bulk of the water is flowing at the same speed and at first glance the entire piece of water might look the same anywhere you look. Looks can be deceiving, though, and time spent in observation will bear fruits. Some spots are favored by a fish more than others, and it's your job to identify them. This should be done before you wade into the river and disturb fish you could have caught. The worst way to discover where trout are lying is by watching them swim away as you spook them. Look for distinct areas that are either advantageous for a trout as well as those that are completely undesirable to the fish.
Knowing where the fish are not, is just as important as knowing where the fish are.
This allows you to prioritize the best places to drop a fly and can direct you to the best places to wade. Any angler's prime directive should be to put the fly where the fish are, and wade where the fish are not.
One of the primary characteristics of a run is that fish can move about relatively easily. If you spook a fish here, they can run a long way and make other fish aware of your presence.
Just driving along the river at highway speeds we can pick out some anglers who we know are having zero success and it comes from that single principle. Any angler standing in good trout water and casting to bad trout water will never do well.
Finding the primary feeding lane is the priority and this will always have a distinct drift line of foam and other debris on the water.
The primary feeding lane is an area of the run where food concentrates more than other areas, and all the foam on the water shows you where the current steers any objects adrift in the water; including objects like fish food. At the same time look for other areas with little or no current. These are typically off to the side and fish will avoid areas without any current if they are feeding. Feeding fish will orient to the drift lines. No food flows into areas with no current, so you can immediately cross those areas off your list of places to drop a fly. Submerged boulders or weed beds will create hidden slots under the surface where fish may lie. Perhaps one bank features good current and depth while the other does not. The more you look at a run of water the more features you will find to steer you into the fish.
Notice Ian has chosen to wade in exceptionally shallow water close to the bank while casting into deeper areas where fish should be positioned to feed.
Now you have determined the best places to cast a fly and the best places to wade without spooking fish, but don't wade out into the river yet!
Have you formulated a plan of how you will get a good drift? A rather extreme example of a bad setup would place the perfect spot to wade and a pod of rising trout 100 feet apart. There's no way the average fly fisher can make that cast, and even an excellent caster will have a difficult time controlling line that far out.
In the most optimal situation, you will be able to wade within a comfortable casting distance of your target without spooking any fish. You should also be able to make any mends to your line to ensure a good drift. Determine ahead of time what type of mend you'll need to make. The set up is even better if it doesn't require you to mend line. Planning is critical to success.
Wade slowly and carefully and only cast after you have gotten where you need to be.
It's best not to move through the water and cast at the same time. Moving while casting can spook fish or worse, cause the angler to stumble and fall. It's not a good idea to wade into the river and continually cast from the moment your shoelaces become submerged.
One of the defining qualities of a run is that fish can move around in them easily so when a fish spooks it will often run a pretty good distance. Spooking trout is never good, but it is particularly bad in a run because spooking one fish will often lead to that fish tipping off others. Unfortunately, the whole episode is over before it ever began when the fish know you are coming.
Long runs can be challenging for anglers to interpret, but with a slow and mindful approach, you'll soon be picking them apart.