Where do you think the encounter between the speaker and the traveler takes place? Is it on the street? Is it in the speaker's head? What does this vagueness contribute to the poem? ozymandias

Yes, the information shown in the text is relevant. The passage is a counterclaim against the other essay on groundwater. The counterclaim shows all of the correct information on why the idea of rivers underground is incorrect, for example in the first article, "People have been using groundwater for thousands of years and continue to use it today, largely for drinking water and irrigation." In the counterclaim it opposes to that idea saying, "At a certain depth below the land surface, the spaces between the soil and rock particles can be totally filled with water, resulting in an aquifer from which groundwater can be pumped and used by people." This shows a claim and evidence to show that the main idea of the text is true.

I hope this helps!