Reservoir Dry Fly Tactics
I've written a few features for the trout magazines in the past focused on our local reservoirs, in these I said how successful dry flies can be, even under the most demanding conditions, space didn't allow me to elaborate on the methods I used at the time, nore how I made my decisions on the days in question, what I would like to do now is go into detail and share some of my experiences with you.
Over the last few years I have concentrated completely on learning how to fish dry flies and emergers successfully under whatever conditions prevail. In that time my boat partner James Gardner and I have come up with certain guidelines that you may find helpful as you puzzle with this intriguing method.
Let me say from the start that none of what I'm about to reveal is totally original as I've picked the brains of many others in my quest to solve the problems that have arisen during the seasons. I now feel confident enough to present our conclusions, these then are our guidelines when making choices during a days fishing.
Let me clarify from the beginning that I'm writing about our experience while fishing reservoirs from drifting boats with teams of flies, that is not to say that these theories will not be useful for you, but that is for you to judge. In my opinion late May is when dry fly fishing starts, by this I mean it's possible to fish dries throughout the day and expect to catch fish. Earlier in the season there will be brief bursts of surface activity confined to the end of the day during the evening rise, which can be very, very short lived indeed.
Around the end of May the water temperature will have risen enough for the fly life to advance and there will be several stages of aquatic flies available, earlier in the season the food was in the larvae/grub form so the trout will generally be focused on grazing the bottom, searching for bloodworms, caddis and immature damsels. With the aquatic fly life ascending to the upper layers of the water, the wind now plays an important part, the current created by the wind drifts the suspended food out over open water, it's now that the rainbow takes on its true nomadic lifestyle leaving the margins and gradually becoming more and more focused on the surface for its food.
Experience has shown that fishing into the wind, or onto the downwind banks, early in the season when the trout are feeding sub-surface, puts you on concentrations of fish.
By late May the fish will be looking for their food to be brought to them on the underwater currents created by the wind, the fish are now starting to move into the wind, and from now on until the season ends the distribution of trout will be effected in this way, moving up wind to wards the windward shores. With the fish spending so much of their time in open water, they're now, unless a Daphnia bloom occurs, focused on searching for food in the upper layers of the water and even on the surface taking adult flies, beetles, ants, hawthorn’s and daddy long legs.
Having given a basic guide to where and when I start dry fly fishing, I'm now going to look at each individual aspect of tackle, flies and technique in depth.

The Mechanics
As previously mentioned I'm expecting the fish to be progressing up wind, so I start my drift at the top of the wind!, fishing from a drifting boat speeds up locating fish and when the fishing conditions suggest dry flies will work, I always drift without the aid of a drogue, as this slows the boat down, where as, I want to drift as fast as possible while leaving my flies stationary on the surface in front of the boat for at least 30 seconds, only when it's too windy to leave the flies that long would I consider the use of a drogue.
As the boat drifts and if the wind allows, I will cast my flies in a fan pattern i.e the first cast across the wind at 45 degrees this spreads my flies out and potentially covers three different paths that fish could be in, as the boat moves towards the flies I slowly take up the slack line and gradually lift the rod ready to roll the leader off the surface in preparation of the next cast which is made slightly straighter and down wind, I like to turn the flies over "in the air" if possible so that the team lands together, this allows me to see all 3 flies have landed untangled, I'm a firm believer that the little impact rings induce the fish to rise! The next cast will be the same procedure as before with the flies cast immediately downwind, always keep the cast short, no more than 15 yards, with spare casting line "at the ready", and always keep a wary eye scanning the water immediately downwind of the boat, as often the fish you see here can be caught, also the way they rise will tell you a lot about how you're going to tackle them during the next few hours. On most occasions I will leave my flies static and allow the fish to come to them, that's why it's vital to fish at short range, this helps you see clearly whether the fish has taken the fly or if it's just boiled at it, fish often do this to drown flies when they are reluctant to push their snouts through the surface, if you can resist lifting at boils then most fish will take the fly at the second attempt, this would not be seen at greater distances than 15 yards, boils would easily be put down as refusals! I leave my flies static for 30 seconds usually, unless fish are seen rising and I'm casting to fish rather than fishing the water ahead of me blindly, in very windy situations I've found it necessary to leave my flies much longer, maybe a minute and use much larger flies, more about this later, this gave the fish more time to fix their sights on their "target" fly.

Leader Construction

For most situations my leader is constructed from Riverge 'Grand Max' fluorocarbon primarily because it's very thin for it's breaking strain and it sinks faster than nylon, in fact 3 times faster, which means my flies are effectively fishing much earlier than if I was still using nylon. I'm convinced that the leader being visible on the surface is the main reason for trout refusing dry flies, this is very noticeable and off putting in calm conditions. Within seconds of casting, my leader is down and out of sight, allowing my flies the opportunity to draw and catch fish, because of its fast sinking properties fluorocarbon even cuts through the surface tension on flat calm days, remember those? In very windy conditions though, as experienced in the autumn, I would consider reverting to co-polymer "double strength" type nylon leader material it's still very fine in diameter, but being less dense it doesn't drag your flies under when you need to leave them on the surface longer. The dimensions of my leader are as follows from the loop at the end of my fly line I have 3' of 7.5lb (.185mm) 'Grand Max', I attach a 2mm solid stainless steel ring to the other end, which is very light and strong and is used to terminate my top dropper, I attach another 4.5' of 'Grand Max' for my mid-section between the droppers, then another 2mm stainless ring for my middle dropper, then finally I attach my point section which is again 4.5' of 7.5lb 'Grand Max', the droppers are of the same material also, each being approx 5" long. Overall my leader is no more than 12', the space between flies is important the greater the spacing the more effective they are at covering more water, too much line above the top dropper causes annoying tangles around the tip ring when motoring between drifts, I can usually manage to keep the fly line just outside the tip ring with this leader length preventing this happening. My preferred knot for tying to loops, rings and flies when using either fluorocarbon or double strength is the highly effective 3 turn 'Grinner'.

Diagram of made up leader and knot!

Location
One thing that has become apparent over the years is the importance of working out where the easiest and largest concentrations of food are likely to be, because you can be sure the trout will have found it first! 'Edges', between the ripple and calm water are vitally important at concentrating food, flies trapped here by the surface tension are picked off at will by cruising trout. A prime example of how effective edges are, is illustrated at the start of each new drift, almost always you see fish rising here and offers come right on the 'edge' between the calm and the beginning of the ripple, also when drifting along wind lanes it's more often than not the fly positioned right in the 'edge' of the ripple that's taken rather than those cast into the middle of the 'calm' area. Another example, which is a real bonus when it occurs is fishing close to aeration bubbles during high summer, I know most anglers imagine that sinking lines are required to catch in this situation but "don't you believe it", dries are outstanding. When the wind's blowing across the stream of bubbles, rather than along their length, is the most productive conditions to fish these areas. The stream of bubbles brings food to the surface where they disperse food in a mushrooming effect. On the up-wind side, the wind compresses this food as it mushrooms across the surface, creating a visible 'edge' close to the centre. On the downwind side of the bubbles the wind creates a myriad of mini wind lanes spreading the food and the fish, drifting these wind lanes can be good, but fishing on the up wind side is better, if you're observant you'll notice the tell tail signs of boils and swirls that do not conform to the pattern of turbulence caused by the bubbles hitting the surface, these extra boils are fish cruising up and down the 'edge' having a feast and once hooked these "pumped up" fish high on oxygenated water go ballistic! One August bank holiday James and I fished Darwell reservoir under exactly these conditions and while everybody else on the reservoir blanked, we both succeeded in taking our limits fishing dries in the manner described.
Another extremely important principle when drift fishing is always to be scanning the water in front and downwind of you, don't forget that this is where you will be fishing shortly and spotting fish at a reasonable distance downwind gives you time to position an accurate cast either directly at them or by laying your cast across their predicted path. I'm convinced that if I can place my flies accurately across the path of a feeding fish I've spotted, then I will catch 50% of them at least! So you see this is vital tactic in warning you of approaching fish.

Weather
Weather & its effect on dry fly success, its been written before by more knowledgeable anglers than myself but it must be stressed again that the key to success is understanding the weather and how it effects the feeding habits of our quarry the trout.

Overcast with ripple
Obviously the absolute best conditions to fish any method for trout is a mild day with overcast skies and a light wind from the west or south west just enough to move the boat and cover water. In these conditions expect trout to rise all day long, make the most of it you'll rarely enjoy such favourable conditions. The fish will remain high in the water even when not actually seen rising, the rises will be fast as the fish try to capture the flies before they escape due to the broken nature of the surface.

Overcast without ripple
Overcast and flat calm can also be very productive with the fish again staying shallow whilst gorging themselves on the insects glued in the surface film, due to the surface tension. The only real disadvantage is without the wind's effect the fish no longer have a current to swim into and become very unpredictable regarding the direction they're swimming in, also in the absence of the wind the boat is almost stationary so you're not covering new water or fish!

Bright and calm
Although bright sunny flat calm 'sultry' days are the kiss of death for most trout methods, the dry fly man is in his element, again lack of wind slows boat movement but the fish will still be willing as they're "looking up" for their next meal, prolonged hot weather forces the trout to go deep seeking cooler water, with very little food at depth unless Daphnia is present, the fish will make brief sorties to the surface to claim any flies stuck in the surface and they are quite happy to feed on the empty shucks of flies that have already emerged, also at depth their window of vision is massive, use larger than usual flies size 10 at least, and wait a little longer giving the trout more time to target your offering.

Bright with ripple
Sunny and windy are the worst conditions imaginable for dry fly fishing, invariably the fish will suspend in deep water feeding on the empty shucks of flies that have already emerged and have fallen down in the water due to the lack of surface tension. If you are lucky your saviour could be a wind or scum lane as this has the key elements for success i.e. surface tension to trap emerging flies and an 'edge' where again food will be concentrated and a ripple-less window in which the trout can clearly target their food! The assumption I've made is the trout are feeding on aquatic flies fortunately this isn't always the case, again back to Darwell it's mid-May and we're faced with sunny, windy conditions and our spirits are low until we start our first drift and bingo a fish takes the point fly a black hopper, fished more in hope than any real expectation of success, I spoon the fish and its's crammed to the gills with, Hawthorns, other terrestrials such as Daddies can also be relied upon to save the day in the autumn under similar conditions. While on the subject of food, there is one other major food source which I've briefly mentioned that can confuse the situation and that is Daphnia! This light sensitive organism throws everything upside down when it comes to location and depth. On bright days the clouds of Daphnia will be deep and we will have very little chance on dries, as the light fades towards evening then the Daphnia will rise towards the surface and now we're in with a chance all be it a slim one, another thing worth mentioning concerning Daphnia is that the trout are less likely to be influenced by wind direction as their food isn't being brought to them in this manner and changes in wind direction will also have minimal effect on them, where as when the fish are surface feeding they become very sensitive to changes in wind direction, we've experienced at Bewl and other reservoirs, when the trout are "feeding hard", the fish will vacate an area within hours of the wind changing, sometimes swimming to the other end of the reservoir.

Size of fly
When selecting my team of flies early in the season I choose dark coloured patterns that sit low in the surface, with their body partially through the film, the flies are quite large size 10 or 12 which might surprise many as dry flies have an image of being delicate little specks of fluff no bigger than a pinhead!
At the beginning of a typical day I'll tackle up with a team of dry/emerger patterns in a variety of styles and colours, my early season team will often consist as follows, point fly size 10 C.D.C. Hopper in black or claret, middle dropper size 10 Taff's C.D.C. emerger in hares ear and the top dropper a size 10 C.D.C. Shipmans buzzer, again black or claret, I'm assuming that no fish are visible and the fish are lying deep, 10' or deeper, so these large suggestive patterns make a worthwhile meal and a very easy target. If the fish are visibly rising and particularly if they're staying shallow I'll switch to much smaller more immatative pattern such as 14 & 16 parachute style dries, in black, hares ear or olive.

Rise forms & depth
I can judge within a little how deep the fish are rising from, by the way they rise. If the fish are lying deep maybe 10,15 or even 20 feet down then their rise to the surface will be short and sharp termed as a "oncer", they will take a surface food item and immediately return to their previous, comfortable temperature depth, it's no good trying to cover these rises as the fish is already returning to the depths and all you'll succeed in covering is its tail!
Fish rising leisurely poking their snout through the surface, or porpoising as they return to their original depth are obviously swimming much higher in the water actively looking for food. These fish will often be seen repeatedly rising for food as they work slowly up-wind, although they're taking off the surface they are not staying that shallow, rather they are patrolling up wind possibly as deep as 2 or 3 feet down which gives them an excellent "window" of vision in which to spot their food. These fish can easily be caught if spotted early enough, always keep an eagle eye downwind of your boat, their speed can be judged by the time and distance between each rise, this gives you the perfect opportunity to lay a cast across their path and intercept them.

Fishes window of vision


The hardest fish in my experience are those that are "truly on the surface", their window of vision is minute, these fish swim speedily, often bulging through the surface as they intercept miniscule food items such as 'green midge', ' jelly fry' and 'caenis'. These surface feeders have a tendency for swiftly changing direction unpredictably, even dropping back downwind only to reappear across from their previous position, only the most accurate casts "right on their nose" will succeed in this situation, I resort to a single fly and reduce my leader length to 9' to speed up leader turnover and improve accuracy.

High or Low ?
I select different styles of dries to perform different tasks, I always mix the styles and colours on my team while I'm searching for fish and only when a successful style emerges, so to speak, will I put all my flies over to one style.

Taff's Emergers

These sit very low in the water making them easy targets creating a large silhouette, the fish do not have to put their snouts out of the water if they don't want to! In bright light or with a cold wind blowing, either early or late season fish are often reluctant to push through the surface to take a truly dry "surface fly".

Shipmans

Lays horizontally on the surface, I prefer C.D.C. versions as they are more buoyant and need less 'Ginking', I'm paranoid about floatants transmitting from the fly onto the leader in warm weather!

Shuttlecocks


REVERSED SHUTTLE COCK!

A bogy fly of mine although I know it works very successfully for others including my boat partner James. My problem with this fly occurs as my leader sinks, the fly instead of sitting upright as intended lays on its side on the surface, I've tried slim non buoyant bodies 'hard bodies' to solve this problem with slightly better results, maybe if I used this pattern on the point position rather than on my droppers it would help? Anyhow as usual I've come up with a rather "off the wall solution" that works whatever position it's fished in, that is the 'Reversed Shuttlecock' tying i.e. the C.D.C. shuttlecock off the bend of the hook, now once the cast is completed it's easy to see the fly cock just like a "waggler" float standing up!

Hoppers

Another emerging pattern that works very well although again I've had trouble getting this fly to perform consistently. Getting the fly to sit very low in the water, its most successful position in my experience, often sees the fly sinking as its dragged under by my sinking leader this is especially a problem in broken, rippled water. Our solution to this is rather crude but very, very effective, the 'Poly Hopper', the addition of a foam loop for the thorax serves two purposes, firstly it allows the fly to sit very low in the water, even in the roughest weather and secondly it can be tweaked occasionally across the surface to induce takes from fast moving "shallow fish", this alerts the trout to its presence.
The 'Poly Hopper' should only be used as a point fly as it twists the leader badly if fished on droppers. Another version that we now use is the C.D.C. version of the hopper which performs as well as the original 'Poly Hopper' except in all but the roughest conditions, more importantly it doesn't twist the leader due to air passing through the C.D.C. loop, this makes it suitable for all positions on the leader.

"High Riding" C.D.C. Sedge
We discovered this fly one autumn on Bewl, it works everywhere we've used it since and at all times of year, it doesn't matter if sedges are present or not! The key to its success is the fact that it can be used in the roughest conditions imaginable. Its ability to ride waves and be seen easily at 10 - 15 yards in grey light in choppy water makes this, a "must fly" for big waters and wild weather, as the Irish say "big water, big fly" how right they are.

Parachutes

These little beauties come into their own late in the day when you see fish starting to rise to very small surface insects. The fish become focused even preoccupied on a particular food item, because they are swimming very close to the surface maybe a matter of inches down they are able to scrutinise your flies more easily and will only take flies that fit the right profile in size, shape and colour, parachute style flies are more immative than all the other suggestive flies I have mentioned previously. Another advantage of this style is that they always land the correct way up and their little white tuft is easily visible in most light conditions at the end of the day, unless you're looking directly into the glare caused by the setting sun.

Shuttlecock Fry
I have to thank Paul Canning for this one, thanks mate! This pattern works better that the traditional floating fry patterns, with the foam back that lay horizontally in the surface, which trout frequently swirl at. The Shuttlecock Fry has white C.D.C. plumes supporting it in the water, its pearl 'Litebrite' body hangs at 45 degrees under the surface, the trout just sip it down often you don't see the fish coming, one minute the flies there the next its gone, fantastic!


A guide to colours
I've compiled a brief list of colours we use for our dry flies and when we use them.

Black
when water temperatures get very high and it looses its effectiveness.

Claret


Brilliantly successful colour that produces all through the season, it's both a dark colour for early season and a warm colour for "high summer" and beyond!

Hares Ear


Another favourite, this clearly suggests food whatever time of the year you fish it. It works particularly well when trout are feeding on fry or chasing corixa. By far my most successful hares ear pattern has been the Taff's C.D.C. emerger in large sizes 10 & 12.
Hot Orange
Fantastically effective, particularly fluorescent, in "high summer" and right through to the end of the season, Daphnia does not have to be present for this colour to work! Favourite patterns in this colour are C.D.C. Shipmans buzzer & C.D.C. Hopper.
Red
Another good summer colour, the brighter the better!

Olive


An outstanding colour when nymph fishing, olive surprisingly, although it works, is rarely outstanding. I often use this in my early season teams, especially when fishing the evening rise with parachute patterns.

Fiery Brown


Another winner, this colour has all the attributes of claret, but more often than not I favour claret.

White
Limited use but has been very effective when tied 'Shipmans' buzzer style with natural white C.D.C. as a mini fry pattern!

Andy Lush
The Friendly Fisherman