sorry
I knew that the water level
:state=0:setvar=$WAT %100
:state=0:water=1,waterfogdist=500,waterred=210,watergreen=230,waterheightofzone=0,state=1
:state=1:etimerstart,state=12
:state=12,etimergreater=500:setvar=$WAT %98,state=2
:state=2,etimergreater=1000:setvar=$WAT %96,state=3
:state=3,etimergreater=1500:setvar=$WAT %94,state=4
:state=4,etimergreater=2000:setvar=$WAT %92,state=5
:state=5,etimergreater=2500:setvar=$WAT %90,state=6
:state=6,etimergreater=3000:setvar=$WAT %88,state=7
:state=7,etimergreater=3500:setvar=$WAT %86,state=0
does not work