NB! It seems this console command is not compatible with CS2.
Command Profile

FOG_ENABLE_WATER_FOG

CS:GO

This command enables water fog if set to 1. If set to 0, water fog will be disabled. Note that you need to override your map's fog settings with fog_override 1.

Syntax
fog_enable_water_fog [0 / 1]

Description

This command enables water fog if set to 1. If set to 0, water fog will be disabled. Note that you need to override your map's fog settings with fog_override 1.

Syntax And Arguments

fog_enable_water_fog [0 / 1]
0 / 1 Enter 0 to disable water fog. Enter 1 to enable water fog (default).