A – MAIN FLOW B – CREASE C – SLACK WATER

SPEED OF FLOW

“The speed at which we see a river flowing at the surface is very different to what is going on close to the bottom. There, water experiences friction which slows it down (this is why holding back a stick float to slow it down works too), so the flow that fish close to the bottom experience is only a fraction of the speed at the surface. In big floods the current close to the bottom is pretty rapid and there will be lots of debris coming down, which the fish will want to avoid. This combination pushes them into the margins.”

SHELTERED MARGINS

“All fish ultimately end up in the edges, out of the main flow. Smaller species will go first, followed by the predators, and finally chub and barbel. The reverse occurs as the water recedes, and I think fish tend to leave the slacks a lot faster than we imagine. Certainly within a day or two of the level starting to drop, they’re on the move.”

UPSTREAM MOVEMENT

“Fish often push upstream during floods. They use this opportunity to get over weirs and other obstacles normally too shallow to cross. Floods in the autumn and spring when the water is warm will cause fish to move a lot more, whereas in winter the fish will tend to stay put as the temperature is lower.”

TARGET ‘THE CREASE’

“Despite it being a complicated picture, I think that anglers are not far wrong in presuming that fish will push into areas of slack water in really big floods, although we all probably over-estimate how long they will stay there.

“The crease between the main flow and the slack is one of the best places to target. Most fish will gather here, because it’s where food items accumulate.”

AUnlike chub, barbel are well equipped for holding station tight to the bottom in heavy flows – but they expend a lot of energy in doing so. bThe crease line, where the main flow meets slower water, is a highly productive area to target both chub and barbel in floods. cActing as a refuge from turbulent water, slacks always hold fish, and are free of debris being carried downstream. MAiN flow creAse slAck wAter