Now I recalled that question and made a quick fact check.

The basin area of river Nalchik (that's where we were camping) is 440 km2. An average flow in the river is 2.7 m3/s. An average rainfall in the Kabardino-Balkar Republic is ~200 mm. All that is public data published by Rosgidromet.

Now if we take that 200 mm of rain per year on area of 440 km2, it makes roughtly 1.1e8 m3 of water. The water then flows for a year (365*24*3600 s) which makes... 2.7 m3/s.