The journal · Conditions
Low, Clear Summer Water
When the river shrinks and warms, the fishing day moves to its two ends and the first piece of tackle to reach for is a thermometer.
· 4 minute read · 937 words
Stop fishing at 20°C. Put that at the head of the page, because everything else about summer low water is technique and this is not. Warm water holds less dissolved oxygen, and a trout played hard at 20°C (68°F) may swim off looking well and die in the night. Carry a thermometer on a cord, take the reading in moving water at knee depth, and if it shows 20 or more, wind in. Between 18 and 20°C, fish only if you can land each trout fast and release it without lifting it from the river.
The day has two ends
A river in late July is coolest just after dawn, having shed heat all night, and warmest between about 15:00 and 18:00. So the trout’s day and yours fold in on themselves.
| Time | Water | What to do |
|---|---|---|
| Dawn to about 9:00 | Coolest of the day | The best fishing. Trout are in thin water and on the tailouts, feeding on spent flies and midges. |
| 9:00–12:00 | Warming | Shaded banks and riffle heads only. Terrestrials under the trees. |
| 12:00–19:00 | Warmest | Take the temperature, then most likely sit down. Watch, walk the beat and mark where fish are lying. |
| Dusk into dark | Falling slowly | Sedges and spinners over the glides. Check the thermometer again before starting. |
Where the fish have gone
Low water concentrates trout. Look first at the riffle heads, where broken water tumbling into a pool carries the most oxygen and the first share of drifting food. Fish that spent May spread through the glide will be lined up in the fast, bubbled water at the top, often in less than 40 cm. Look next under the trees. Shade can be a degree or two cooler, and from June onwards the branches drop a steady supply of ants, beetles, aphids and small black flies.
- Riffle heads. Short casts, a size 18 nymph or a small dry in the broken water. The ripple hides your leader and you can get close.
- Shaded margins. A size 16–18 foam ant or Black Gnat, dropped within a hand’s width of the bank. Let it sit. Terrestrial takes are slow and deliberate.
- Springs and side streams. Cooler inflows gather fish in hot spells. Leave these alone. Trout crowded into a refuge are under stress and should not be fished for.
Long and fine
In water like glass a nine-foot leader lands the fly line far too close to the fish. Go to 12–15 ft. The simplest way is to take a 9 ft leader tapered to 5X (0.15 mm), add 60 cm of 6X (0.13 mm), and finish with 90–120 cm of 6X or 7X (0.10 mm) tippet. The long, soft end turns over gently if you cast with a slightly open loop and aim half a metre above the water, so that the fly falls and is not driven down. A 3 or 4 weight line lands more quietly than a 5.
Flies shrink with the river: sizes 18–22 are normal. A Griffith’s Gnat or an F-Fly in size 20 covers the midges and smuts that trout sip in the film on summer mornings. With 7X and a tiny hook, set by lifting, not striking, and use a softer rod if you own one. There is a tension here that needs saying plainly. Very fine tippet lengthens a fight, and long fights are exactly what warm water makes dangerous. Use the strongest tippet the fish will accept, bring every trout in firmly, and if 7X means playing fish for minutes, go back up to 6X and take fewer rises.
In low water the cast that catches the fish is usually the one made from the bank, on your knees.
Stay out of the river
Wading in a shrunken stream sends pressure waves and silt down every pool, and on a flat glide the ripples from one careless step travel twenty metres ahead of you. Fish from the bank wherever you can. Kneel. Keep back from the edge and cast over the grass if need be, with only the leader on the water. Where you must cross, do it at a riffle, slowly, and then give the pool below ten minutes.
Clothing counts more now than at any other season. Wear olive, tan or grey that matches the bank behind you, with nothing white and nothing that shines. A bright rod flashing in hard sun warns fish at long range, so make fewer false casts and keep them away from the fish’s lane, off to one side.
Resting fish
Summer trout in clear water do not forgive a second mistake. If a fish stops rising after your cast, do not send another over it. Sit back, change nothing and wait until it has risen freely three or four times, which may take five minutes or fifteen. Then make one good cast. If it bolts, it is gone for the session, and so are the fish it ran past.
- Play the fish quickly, with the rod low and to the side, and bring it to a rubber-meshed net.
- Keep it in the water. Unhook it in the net with wet hands, and skip the photograph.
- Hold it facing into gentle, well-aerated current until it swims off strongly. At the tail of a riffle is ideal.
- Take the temperature again. The river warms by the hour, and what was safe at seven may not be at ten.
Low water teaches patience more thoroughly than any other condition. Two fish taken well before breakfast, both released without leaving the stream, is a full day.