In April of 1996, I was invited to participate at a Conference in Santa Catarina, Brazil, convened by Universidade Regional de Blumenau (URB) to examine the environmental impacts of the proposed levee scheme for flood control in the Itajai river at Blumenau.

The evening of the first day of the conference, I joined several attendees for dinner at a local restaurant. I struck up a conversation with a young man, who told me that he was finishing his Ph.D. at the University of Milan, and would soon rejoin the civil engineering faculty at URB.

I asked him about the topic of his dissertation, and he said that he was applying the diffusion wave in a DTM context to model distributed catchment runoff. Noticing that he had sparked my interest, he went on to say:

"I used the Muskingum-Cunge diffusion-wave model, with lateral inflow calculated with the routing coefficient C₃ derived by this guy named Ponce."¹

My response nearly toppled him. I said: "I am that guy."

The Ponce monolith in Tiwanaku, on the Bolivian high plains.