While it is possible to get to some of the suggested sites for this wonder (The Usk; The Wye), the Troggy Whirlpools (or "Whirly Pools" as they are known locally) are currently on private land (and thanks go to the landowner for access in our attempts to tie down their locations). It is, however, possible to see the area from a variety of roads, as the photos below will show. Here's a overview Photo of the area.
The Whirly Pools appear to have alternated between discharging and swallowing water, acting as resurgences of water that entered the underlying bedrock further up-valley. This seems to have occurred just outside of living memory, infact until alterations during the building of the Severn Tunnel when they may have been filled in (See Science). There are two main "Whirly Pools", as can be seen on the 1775 Map. Neither now have pools (Modern Map), though the lower pool site (right on the maps) is on the edge of a area that floods annually, and may still contain a resurgence of water.
The area of the whirlpool highest up the stream can be seen from the junction near Brockwells Farm marked with a phone on the modern map (Photo). Within the field it is possible to see the hollow the pool would once have occupied (Photo), and the bed of the stream which would once have drained it (Photo). As can be seen from the photos, there is a height difference of a couple of metres between the edge of the pool hollow and the bottom of the Troggy valley, making it less likely the tide ever reached this pool, even if it reached the lower Whirly Pool.
The lower pool