Somehow, even photographs taken more than 30 years ago get flipped upsidedown when posted on the internet. Flipping images with metadata tags, which are inevitably ignored or stripped, has proven to be an extremely user hostile technical decision.
Interestingly, the concrete channel looks similar to those in Central Asia. (The latter have holes in them to let water seep into the ground.) Street view: <a href="https://maps.app.goo.gl/pvrsiYMCfeADo8NL6" rel="nofollow">https://maps.app.goo.gl/pvrsiYMCfeADo8NL6</a>
Has anyone visited these sites in the last few years? (The field trip was in 2006.) Has construction, road repairs, etc. obscured many of these? I know of a few roadway offsets in the immediate Bay area that have been "fixed" and are no longer visible.
(Unrelated) oh wow, ResearchGate actively begs authors to upload their full text in order to make it accessible, but prevent the public from downloading said texts unless you have a RG account?