Because of the flooded river Maas there is an increased amount of helicopter activity over this river.
Seen at sunday 09/01/11 in about 15 minutes:
Belfeld
1x R.44 black c/s
Flying very low near the weir in Belfeld. I was too late to make a picture
Tegelen
PH-LPH EC.120B HPL Metals
A picture can be seen at http://hoebers.fotopic.net
I guess most helicopters will fly inspection-, media- or sight seeing flights overhead the flooded river.