Beside the Severn next to the Severn Way.They seemed to be in pairs a few hundred yards apart but what are they for?
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Thanks for the suggestion.
There were at least two pairs, one each side of Oldbury power station and another pair closer together near Berkeley Power station. Very primitive looking things...hardly advanced technology!!
If it ain't broke, don't fix it, and the best technology is always the simplest that does the job to the required standard.
Very cheap and if the method of sampling was changed, you could not make comparisons going back in time unless you did mind-numbing amounts of duplicate testing and cross-checking.
given that they spend most of their time unattended in spots where access is easy, this is the best idea. Anything more sophisticated would attract vandalism / theft (more than usual!).
Lat/Lng: 51.6, -2.6
OS grid ref: ST6094