In 1996, I visited the U.S. Army Corps of Engineers' Hydrologic Engineering Center, in Davis, California. There I met Arlen Feldman, who was at the time head of research at the famed center. I asked Arlen what was the status of the HEC-1 model, since I had heard rumors that it was being replaced with a graphical-user-interface (GUI) version. Arlen responded that they had placed HEC-1 on the back burner, and that they were working steadily to release the GUI version as soon as possible, to be renamed HEC-HMS, for "Hydrologic Modeling System." (Version 1.0 of HEC-HMS was released in 1998). I complimented Arlen on their efforts and was about to leave when he said: "You know, in order to acquire the GUI capability, we almost had to sell half of the shop."

Many other established hydrologic models have not made the transition to the GUI version. I wonder if it had something to do with what Arlen was referring to.

Physical model of the Kosi river basin, near Chatra, Nepal

Physical model of the Kosi river basin, near Chatra, Nepal.