Rising water levels
Unsurprisingly, I’ve been thinking about water. On the day after flood Sunday I went down to the Old Bridge in Ilkley to survey the scene. The Wharfe rises and falls quickly so, though we could see where water had flooded the nearby fields and streets, it had now returned to its course. Brown and turbid, it fairly racketed under the Bridge. One wonders how any creatures could survive in such a violent and unpredictable environment – and yet, of course, they do. Presumably the kingfishers, dippers and herons retire to forage in smaller tributaries, and the mallards seem positively to enjoy dabbling in the new pools in what are usually fields. But the creatures living in the water – the crayfish, the small fry and all those invertebrates that sustain the food chain have evolved to hold out in the boulder-crunching torrents, by hiding under stones and in the quieter nooks at water’s edge, perhaps.
The sudden rises in water level here are partly due to the great network of streams that pour down from the wetter uplands. These streams provide some of the most attractive scenery in our area. My earliest memories are of playing in and around such a beck – a wonderful start for a lifelong interest in natural history. It had everything – rapids, shallows, deep pools and mysterious culverts stretching darkly beneath the branch railway lines. The fauna was typical of such streams – caddis-fly larvae, each with its carapace constructed from sand-grains, other detritus and tiny pebbles; fearsome monsters in miniature – the nymphs of gold ringed dragonflies – that lay their eggs in peaty streams; sticklebacks, the males resplendent with rose-red chests and bright turquoise eyes; and even, in deeper pools, small brown trout that we tried completely without success to catch in our hands by tickling.
Following the beck back to its source, you arrive at the moors with its sudden springs and peat bogs. These boggy areas are known locally as “mosses” and here it is the flora that I find most interesting, particularly the sphagnum moss with its pale pink and green colours and its wonderful properties. Sphagnum acts as a giant sponge – able to absorb water up to 25% of its dry weight and then let it out gradually into the water-courses. It is antiseptic , widely used during World War 1 as a wound dressing, and it locks in great quantities of carbon thus helping to reduce global warming. Wonderful stuff!