A rhyne (pronounced "reen", from the Old English ryne or Welsh rhewyn or rhewin "ditch") is a drainage ditch, or canal, used to turn areas of wetland at around sea level into useful pasture.
Water levels (and hence the level of the water table) will usually be controlled by a system of sluice gates and pumps, allowing the land to become wetter at times of the year when this will improve grass growth. Rhynes represent an early method of swamp or marsh drainage. Large sections of swampland were surrounded by trenches deep enough to drain the water from the encircled mound and leave the land relatively dry. Regular clearing and dredging is necessary to keep the rhynes clear of debris so that they flow freely.
Source: Wikipedia
Limited parking is available nearby. Wheelchair users should have no difficulty at all with this one.
You'll need tweezers or some other pointy thing to extract the log - before replacing it, please squish it nice and flat so that it's easy for the next cacher to remove 
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Well done robnrsheils for being FTF!