Fly Fishing on Reservoirs in the Summer: How to Find Success

Fly fishing on reservoirs in the summer can be a difficult for all reservoir anglers. Throw in a number of hot still sunny days and the water temperature becomes much warmer in the surface layers, and less oxygenated. This means the fishing becomes increasingly difficult as the day progresses.

As always, I adopt a simple and logical approach to my fishing. So, I divide the day into 3 distinct parts:

Early Morning:  04:00am – 09:30am

Daytime:           10:00am – 7:00pm

Late Evening:    7:15pm – 11:00pm

Early Morning and Late Evening

The tactics for early morning and late evening are identical. I also accept that the summer months are often difficult, and the fish is erratic. For me it’s the time of the season ticket angler or a dedicated day ticket angler rather than the occasional fisherman.

Early morning and late evenings provide the only realistic opportunities for the bank angler. Resident fish are on the feed and they will leave the safety and comfort of the deep water and venture into the shallows to search for food. I always look for clear water and a natural feature such as a large weed bed or drop off as a starting point. Then, if I receive no action within 15 minutes, I move and cover water as I must find the fish.

Try and have a clear plan of where you are going to start, and where you will move to if it doesn’t work. Time is of the essence. In shallow clear water numerous casts and large flies only do one thing: spook the fish. A stealthy approach is key to success. As such, I will only fish methods that require little casting. The “washing line” or “dries” are the obvious example of this.

The washing line.

My initial line of attack is usually the “washing line” method. I use a floating line or 6ft slow tip with a 15ft leader of 8lb Co-Polymer (degreased). On the point, a Foam Daddy. On the droppers, two size 12 – 14 red holo diawl bachs.

When you make a cast, give one pull to straighten the line and get you in direct contact. Then. fish ultra slow or static.

Fish are often pulled to the silhouette of the larger daddy but ultimately take the diawl bach’s subsurface. On some occasions (ie. flat calms or if there is a large presence of fry in the area) I will often replace the foam daddy with a suspender minkie. The mink tail imparts a small amount of movement into the pattern as it will move on any undercurrent. Often it’s all that’s needed to induce the take and turn swirls from merely interested fish into positive takes. A suspender Minkie can also be given a sharp strip to create a “pop.” Again, this disturbance can pull the fish to your cast.

Fishing dries.

My only other tactic is to fish “dries.” This is especially true for Corixa and Stickleback feeders. Again I tend to keep things simple with a 13ft leader of 7lb degreased co-polymer with a size 12 Hare’s Ear CdC on the point, and a size 12 or 14 orange hopper on the dropper. I’ll tie this 5 ft from the point.

With both methods you can literally “park” your flies out there and simply wait for the fish to find them. Remember to keep movements to a minimum and the fish will feed confidently just yards from the bank, especially in low light conditions. It’s a really exciting time, and the fish you are targeting are always much larger than average. Shallow , clear water leads to long and fast runs from powerful fish and It’s the nearest thing you can get to fishing “the flats” in the UK. However once the sun is out then your opportunity has passed. You must accept it won’t last all day. Fishing during the “daytime hours” is often pointless.

Daytime Hours 10:00am – 7:00pm

In truth, during between these times in the summer months you really need to be boat fishing if you want to catch consistently. From the bank you have very limited areas that provide access to deep water such as dam walls and pontoons. The fish will have now moved out of the shallows and into the deeper water. They will often hold at a depth of between 15 and 25ft.

As at any other time of the year you must fish the reservoirs features with deep water (water 15ft or deeper) if you are to be consistently successful. Aerators, draw off towers, marker buoys and pontoons all attract fish in the hot summer months. Aerators pump in cool moving water and can be like a magnet to fish during the months of July & August. I accept fishing these areas can be too easy. 

Fishing features.

The other features highlighted above will all have weed on them. This in turn attracts natural foods such as fry, shrimps, corixa etc. In these locations, you should aim to fish along or next to the feature, rather than out into open water. Angle the boat to suit your casting and go from there. This is best done by means of a “G” clamp.

There are really only 2 approaches I consider when fishing deep. The first being the traditional approach. This is to use heavy sinking lines ( Di-5 and Di-7’s) and lures such as snakes, cat’s whiskers, boobies and humungus‘. Despite anglers’ reservations to this method  and style of fishing it just can’t be ignored. It’s so effective at this time of year. It produces fish when everything else doesn’t.

The deep water setup.

My typical setup would be a single fly. This is usually a 2.5” booby style pattern, like a Black & Green or Hummungus Booby. With this single fly I use a 10ft leader of 8 – 10lb flurocarbon fished on a Di-7 sinking line. Simply cast as far as possible and leave the fly to sink.

The most common mistake with anglers when fishing boobies is not letting them sink for long enough. A 15 second count is the minimum I would consider. I would tend to let the cast sink for between 20 and 40 seconds before I start my logical approach and work the depths. I always start my retrieve with a single 3ft hard pull, this basically pulls the booby and creates a huge underwater disturbance (with the booby eyes). This will get the attention of any nearby fish, and a slow steady figure of 8 will be all that’s needed to get takes. If you experience soft takes or a “tap-tap-tapping” just keep retrieving until everything goes solid. Often the fish will come back time and time again before actually swallowing the fly with a vengeance.

While I often successfully employ this tactic and do not doubt it’s effectiveness especially on hard fish and deep waters, it can become a little too monotonous and predictable. It’s also not suitable for those of you who practice “catch & release” as fish can be deeply hooked. Alternatively fish a Hummungus or Snake with a “roly poly” retrieve. It’s is equally effective but much more strenuous.

How deep are you fishing?

Many anglers do not know just how deep they are fishing, they often guess, hence the reason that some catch and some don’t. Counting uniformly will make a huge difference to your fishing and will allow you to work out the depth the fish are holding and the depth of water you are fishing. The following sink rate chart is invaluable for me. Remember just keep in touch with your line on the drop as it sinks – a fast figure of 8 will hold the line and cast up in the water.

Sink rate chart

I methodically work the depths of the water in front of me. I will start by fishing 3 casts at 15ft then 20ft etc. Once I get a take I concentrate my efforts at this depth, aim to get the “majority” of your takes when half the fly-line is back in the boat. This will mean you catch those fish that are slightly higher in the water and deeper in the water – fish do not all hold at exactly the same depth, and move up and down in the water during the day. 

Obviously the longer casters among us have a huge advantage when fishing deep, as they present their flies deeper for longer. One trick I have learned is that if you cannot cast a full line (or if the fish are really deep) and you are fishing at Anchor or in a flat calm, flick two or 3 rod lengths of line over after you have finished your cast (same when fishing deep water from the bank). This will allow your line to sink level…and so will present your fly deeper for a longer period of time. 

Deep nymphing

The only other method I would consider when you are required to fish deep is “Deep Nymphing”. On it’s day it’s equally effective and more pleasurable than fishing lures. It’s however best when the water is clear. For me a “Mini Tip” line such as the Airflo 6ft Fast Tip is essential. This line has a 6ft sinking tip of fast intermediate line (sink rate 1.75” per second) and allows anglers to fish nymphs deeply without need for ridiculously long leaders tat cause tangles and frustration.  

A standard set up would be a 7ft to the top dropper, a further 4ft to the middle dropper and 4ft to the point (total Leader length 15ft). A heavyweight size 8 buzzer (or goldhead buzzer) should be placed on the point size 10 nymphs on the droppers, this set up will actually drag the floating section of the fly – line down 3 or 4 ft. Don’t worry – this is totally normal and you will now be fishing your flies at depths of  14 – 22ft.

Just fish static or with an ultra-slow figure of 8 retrieve and watch the fly line as an indicator. If it moves slightly or sides away, lift into the fish. If you catch weed occasionally either shorten the length of your leader slightly (to the top dropper) or employ a slightly faster figure of 8 retrieve to keep the flies slightly higher in the water. Takes are as you would expect when fishing natural patterns at depth: confident. The line will just draw away slowly and firmly.

To read more on fly fishing reservoirs, read Rob’s other articles on our blog!

Rob Edmunds

Rob Edmunds is a stillwater and reservoir fishing expert. "I began fly-fishing at just 4 years old and match fishing soon became my primary focus after first representing England at just 16 years of age. A stellar career beckoned and I've been fortunate enough to win a number (9) of European titles both individually and as part of a team. A creative fly-tyier and responsible for many of the popular patterns we now take for granted (Nemo, Tequila Blob, Traffic Light Buzzer, Snake Booby etc...). My focus has shifted slightly in recent years to targeting specimen trout. Currently the only person to have ever caught at least 1 "double figure trout" from all 4 of the Anglian Water Reservoirs. A regular contributor in the angling press for over 20 years (Trout Fisherman, Trout & Salmon) and well known on the stillwater and reservoir circuit.

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