Lagarfljot is that rare thing, at once a lake and a river — a long, narrow glacial ribbon stretching twenty-five kilometres past Egilsstadir in east Iceland, fifty-three square kilometres of water more than a hundred metres deep in places. It carries the glacial outflow of the Jokulsa i Fljotsdal off the Vatnajokull ice, and the rock-flour gives it a distinctive murky blue-green colour and poor visibility. The shores rise into Hallormsstadaskogur, Iceland's largest forest, beneath the red-striped Hengifoss — and, by long tradition, the lake holds the Lagarfljotsormur, the serpent of medieval manuscripts. As fishing water it is a big, deep, glacier-fed system on an almost imperceptible gradient, read by its inflows and margins rather than its bottom. Wading has little part to play here; this is boat-and-bank water, approached with the patience a large, opaque, cold lake-river demands.

Wading: Deep, opaque, cold lake river