This song is probably about a dam that I learned about in a geology class. After the failure, somebody took a sample of the earth material from the abutment (natural side of the dam), and the material broke down into a little pile of gravel. It had been cemented together by natural salts, and when the water level rose in the reservoir and in the pore space of the abutments, the salts dissolved and it all collapsed.

The image of the beaker with the loose rocks in it has never left me.

Dam-building has slowed way down now, but now if anybody builds one or modifies one, there is much drilling and testing done ahead of time.

Joe, thanks for posting the song. I like it.