Black Keld has been shown, by Myers, to be the resurgence of the Mossdale water, having a flow which is copious, peaty and liable to flooding. On the other hand, Spring Trap Cave, described in the previous article, contains clear water which is trapped by the neighbouring water pump. Midway between these two lies a still pool of water whose height fluctuates slightly but which can flow in very wet weather.

Measurements of the pH (acidity) of these waters taken using indicator papers graduated in steps of 0.3 showed no difference between Spring Trap and the pool, but indicated a lower value (higher acidity) for Black Keld. There is no point in quoting the actual pH values obtained by this method because of the inherent inaccuracy, but the relative values were significant. These results are consistent with Black Keld being fed with peaty, acidic water which, due to recent flooding, had not regained an equilibrium value, and to the other two springs being fed by underground pickup and drainage directly from the limestone surface. This contention is further supported by the fact that, when the pool floods, it flows clear whereas Black Keld becomes very turbid. This also provides evidence in favour of the contention that water tables in limestone are local and discrete since we have here an example of at least two large bodies of underground water in close proximity and yet, apparently, quite unconnected.

> NPC Red Journal 1963:
---> Next page: Some Thoughts on Douk Gill Scar
---> Back to contents
---> Previous page: Diving Reports
> Out of print publications list
> Northern Pennine Club Home page