Fishing for Trout: Reading the Water – Part 4


By Bryant J Cochran, Jr.


This installment of reading water deals with details for the fast water types described in part 3. If you have not read parts 1-3 I suggest that you print them or save them to your machine for reading off line at your leisure.

Rapids, riffles, pools, pocket water, slicks, eddies, these are the types of water you fish in a river or stream. The places fish like to call home are found in each, your job is to recognize the feeding lies, see the fish and then cast to a position so your fly (lure) passes where the trout will see it and hopefully eat it. In the last installment I glossed over each type of water to give you a way to go to the stream and try out your new knowledge. Now it is time to get into details.

Rapids are the fastest water flows in a stream. They are at least three feet deep and usually have shallow areas and deep pockets that the current has dug out of the streambed. In order to be able to find these different areas, a little information on hydraulic action of water currents is needed.
To begin we will look at the effect the streambed has on current flow. The water just above the streambed will flow slower than water further away from the streambed; this is due to friction of the water against the streambed. This “pocket” is normally a foot deep. You can check this in an area with a weighted nymph on a long, fine leader, in clear water. Cast up stream and watch the speed of the nymph as it sinks, you will be able to discern several different flow rates as the nymph sinks and you might even see a change in direction of the drift. Knowledge of this can make the difference when casting to a specific fish. A boulder in the rapids causes several different conditions around it. First it blocks the flow and forces the current to split the resulting friction slows the flow rate on either side of the obstruction. An area of slack flow is created immediately in front of the boulder; a slower flow is created down stream of the boulder (this is usually further down stream than you might think) found just behind the visible turbulence down stream of the boulder. If you find two or more boulders forming a dam-like structure you might find a deep pocket down stream of this structure, this is the result of the flow deflections caused by the structure. A formation like this also forms an area toward the bank, extending out to approximately the inner edge of the stone closest to the stream centerline and down stream approximately the length of the dam. In other words, a triangle from the outer most stone to the bank shaped similarly to a 30-60-90 triangle. This area can be very productive, slack current with a seam line running from the outer most stone to a bank junction point. The main thing to remember is that any object in the water is going to effect the current flow in some manner. Fish will look for the slowest water they can find next to a feeding lane (think food conveyor belt). When there is deep water or other cover close at hand as well then you have the makings of a prime lie and the bigger fish will want this type of environment for their home.
Now back to the rapids. What you want to look for in fast moving water are places where the current changes flow-rate. The best place to observe the water and the flow-rate is from as high above the water as possible. Keeping a low profile will ensure that the fish will have a hard time seeing you and you will be able to see into the water with fewer glares to contend with. You will be looking for all the things that cause the current to slow. Large and small boulders, flat areas on the streambed, moss heads, under-cut banks, bank walls formed where a shelf drops off, dips and holes in the streambed, bank protrusions into the current, logs and fallen trees that have become lodged against the bank. Each one of these types of flow disrupting structure must be thoroughly investigated with a studied eye else you miss seeing a fish. You also need to be able to discern the different current flows caused by these obstructions and recognize the feeding lanes that the obstructions set up. Remember that the only difference between Rapids and riffles is the average depth of water.

Pocket water could be described as Rapids but the true nature of pocket water is more specialized than the Rapids description. Pocket water is fast moving current with the streambed literally strewn with boulders and rocks. If you were a boater, pocket water would be very frightening or you would simply portage around it. When looking at pocket water for the first time you will probably know it is pocket water instinctively. The boulders and rocks of pocket water usually end up in the streambed as the result of a rockslide. I was very fortunate to see a section of the Truckee River become pocket water on a fishing trip. I was also very lucky (Grace of God) to survive the event. I went back to that stretch of river two weeks later and the fishing was magnificent! The term pocket water comes from the myriad of pockets of slow water created by the jumble of stones in the streambed. Trout seem to love all the slack current and the intertwining of food lanes that occurs in pocket water. Survey this type of area like you were going to be selling maps of each fishy location and you will never leave with out having caught a few. The one big drawback to the tailwaters I fish now is that I have no pocket water to exploit. The best tip on pocket water I can give is take time to get above the beat and carefully study the way the current reacts to boulder singles, doubles, triples, and all other stone arrangements. Keep your eyes open and looking for the little “windows”(areas of very smooth water that form in conflicting current flows) these will give you the ability to see deeper into the water with a clear view.

I hope you will take the time to draw a map of each bit of water you explore with your new knowledge. Marking where you see fish holding and giving your self-some type of indication of the current flow in the area of each fish spotted as well. Every fish spotted needs to be observed long enough for you to be able to tell if it is feeding or resting. A twenty-pound trout that is in a resting lie will most likely be a non-cacheable fish.

When you go fishing I hope that you don’t wade right in and start slinging line. I see lots of fishermen do that on my home waters and they are usually lamenting about their lack of success when they are going home. The thing is, they do not prepare themselves to be successful before they start casting. Time spent looking at the water you intend to fish will allow you to locate the places in that beat that should hold fish. Time spent looking in the located lies will allow you to see the fish holding in those homes and how they are feeding. This information gives you the knowledge base needed to use the right type of lure (fly) right off the bat. You also know where to start your presentation to that fish so you get the best opportunity to hook up. When you take this pre-fishing time you also have the location of every fish you could see before you make that first cast. This means that you can adjust your starting point so you have the best opportunity to catch all the fish you spotted. Sure some anglers can catch fish by blindly going forth into the fray, but these fellows would increase their catch quantity and quality if they would try some stream investigation first. Here’s an example of what I am trying to get across. I was on the Little Red at Cow Shoals a while back, as I approached the stream I was delighted to find the water level low. The river is tail water and for me low water means easier fish spotting. As I walked the bank, noting the lies and listing them in order of importance in my stream log four fishermen came to the shoal. These fishermen walked up the bank, waded out and began casting and drifting nymphs, not one of them took time to scope the water before they started fishing and they were at the head of the riffle when they waded in. I was higher than they were and saw five good fish bolt to the pool above the shoal. These fish had been holding only a foot or so from where these guys splashed in to the water. Their haste to begin fishing cost them some great fun right from the start. I continued my stalk of this beat and a half hour later, when I was ready to make my first cast, these fishermen were complaining “I don’t think there are any trout in here today” one of them said to me. My reply was “tough day mate?” Two of the four watched me carefully take a position in a stretch they had fished about twenty minutes before. I made a cast one foot ahead of a bulge in the water and held my line up as the gold ribbed squirrel nymph drifted in the seam formed by the submerged rock, I felt the take and after a strip strike I had my hands full. When I landed what turned out to be a 24-inch brown trout, I heard a gentleman remark “we fished the heck out of that riff and didn’t get anything! He just walked in and hooked a big one!” I caught and released seven fish of quality in the next two hours. Those four fishermen went home skunked and discouraged. After I ate lunch on the bank, I went down stream to the second pool after the riffle. There is a nice high bank with a walk ledge on the far side of the stream. After carefully crossing at the tail of the pool I crept along the ledge, looking down into the water. This pool has two really deep holes on the far (right) bank and plenty of moss heads; there are four good boulders as well as an undercut bank. When I observe this pool I have to look for perceptions of fish, the cover is dense and usually all you will see of a trout is the tail moving. I spotted one between the bank and the first boulder as it sipped in something; the flash of a white mouth gave it away. I watched him sink to his holding position and his camouflage made him almost invisible. Up stream from that first fish was a large moss head and after looking at the tails waving in the current for about five minutes I distinguished four tails moving almost perfectly in time with the moss tails. Almost directly in line towards the left bank Is the drop off of the shelf you have to use for wading to fish this pool. I spotted five trout lined up and hugging the bottom of this bank wall, it is almost always in shadow and the fish love to be in that shadow. As I watched these fish one of them raised its head and took some morsel from the current about a foot from the wall. I continued my stalk up the pool and when I was ready to fish the pool I knew where twenty-five trout were hanging out. I also knew that I would hook and land at least five and most likely more if I started from the tail of the pool and worked my way to the head. I also knew they were most likely feeding on nymphs swimming toward the surface to hatch. I knew this because I observed the way the trout feeding. As it turned out, I landed and released nine of the trout I had spotted. Two of which measured 25 inches in length, trophy fish to be sure. The two key elements that allowed me to have this success were the patience to look stealthily for fish and the calmness to move very quietly through the water.

Next time we will cover the details of slow water, the pools, slicks and eddies. I encourage you to go to your favorite fishing waters. Find a high place to look into the beat and take a note or sketch- pad and pencil and draw the river as you see it. Try to include every detail you find. Try to see the fish living in the homes you find, if you do see them, include their locations in your map. Take this map with you each time you fish this beat. When you have all the houses and all the fish spotted and included in your map you will be able to catch a large percentage of the fish every time you fish this beat. Think of how great it will be when you have done this mapping for each beat you fish.