|
Rivers are much wider than they are deep, although this may not be apparent to a layperson.
For example, the average depth of the Upper Paraguay river at Ladario is 5.24
meters, while at that point the river is about 300 meters wide, that is, the aspect
ratio is 57 to 1. The
Amazon river
measured at the Obidos narrows is about 60 meters deep and 1600 meters
wide, that is, the aspect ratio is 27 to 1.
Yet, people who have not seen the data have a tendency to believe that rivers
are much deeper than they actually are.
During a field reconnaisance of the Upper Paraguay river near Ladario
in January 1995, 1 I asked a local fisherman
if he had been on the river for very long.
He quickly responded: "All my life."
I followed with a question: "How deep is the river at this point?"
He looked at the river, and pronounced: "At least 100 meters deep."
I learned there that local knowledge, no matter how close to the source,
had its shortcomings.
| ||
|
|
