When you are swimming:
press space to reach the max height out of water,look up, then press W+Shift(Run) and you’ll start to run on the water surface, you can even shoot & reload.
Here is an img:
I’ve got a dem file too but I couldn’t attach(zip: exceeded space)
status:
hostname: Half-Life 2
version : 1.0.1.0/14 4104 insecure
map : bm_c1a1e at: -2222 x, -6448 y, -4036 z
players : 1 (1 max)
pos:
setpos -2028.432251 -6311.446289 -4065.997559;setang -19.958975 5.987066 0.001788