This is a still from the recent TV film which we have already discussed at length. It's a somewhat fanciful artistic representation of the two famous "periglacial stripes" which, according to MPP, led Stonehenge to be created here rather than somewhere else. the trouble is that there are not just two of them. Photos show that there are scores of them, quite close together, meandering slightly and with ridge crests often about 50cm above the trough bottoms.
I have already shown this map of the contours around Stonehenge:
Unfortunately, it doesn't show the detailed contours (25 cm interval) for the key part of the Avenue, so all we have to go on are the comments from Charly and Mike that the "grooves" or stripes do not run directly downslope, but DIAGONALLY. This seems to be confirmed on this LIDAR image which I recently came across, in the Field and Pearson Stonehenge Report from 2011.
If you look very carefully at the "grain" showing up on the image (click to enlarge) you'll see that the Avenue is aligned a few degrees away from the direct downslope orientation.
One would need to examine these troughs and ridges quite carefully to try and work out their origins (Simply to call them "periglacial stripes" is highly misleading, since it tells us nothing about the actual PROCESSES involved.)
My money is still on these stripes, which may cover a large part of the landscape beneath the regolith or soil layer, being solutional rills which owe their orientations partly to some structural control in the chalk bedrock. It may be that the presence of a permafrost table might have played a part in this, by preventing the downward passage of surface water and concentrating flow close to the ground surface but maybe within the soil layer. Much more work to be done -- but please can it be done by a geomorphologist rather than an archaeologist?
Source of image: