  In dense colloids it is commonly assumed that hydrodynamic interactions do
not play a role. However, a found theoretical quantification is often missing.
We present computer simulations that are motivated by experiments where a large
colloidal particle is dragged through a colloidal crystal. To qualify the
influence of long-ranged hydrodynamics, we model the setup by conventional
Langevin dynamics simulations and by an improved scheme with limited
hydrodynamic interactions. This scheme significantly improves our results and
allows to show that hydrodynamics strongly impacts on the development of
defects, the crystal regeneration as well as on the jamming behavior.
