24

ADCP

BSHcmod

27m  27m
3  SO  TOO
C-W5

Fig.  10:  Hourly  averaged  spring  tidal  currents  from  6  hours  before  (-6)  until  6  hours
after  high  water  at  Borkum.

The  dominant  signal  in  North  Sea  current  data  is  the  semi-diurnal  tide.  The  results  of  a
tidal  stream  analysis  are  shown  in  Fig.  10  (spring  tide).  Generally,  maximum  flood
currents  can  be  observed  2  hours  before  high  water  (HW)  at  'Borkum  Sudstrand 1  which
was  chosen  as  port  of  reference.  An  exception  are  the  ADCP  spring  HWs  at  5  and  11  m
depth:  here  maximum  flood  currents  appear  already  3  hours  before  HW.  The  model’s
maximum  flood  currents  generally  exceed  those  recorded  by  the  ADCP.  At  both  data
sets,  maximum  ebb  currents  occur  at  5  hours  after  HW  with  model  currents  again