  Essentially all high-redshift galaxies show evidence for strong large-scale
outflows that should have a profound effect on the structure and kinematics of
both the galaxies themselves and their environment. The interstellar absorption
spectra of both Lyman break galaxies (LBGs) and local starburst galaxies are
remarkably similar to those of damped Ly-alpha (DLA) systems in QSO spectra.
Their rest-frame UV spectra typically show broad, blueshifted Ly-alpha
absorption accompanied by low-ionization metallic absorption lines with complex
profiles. Hydrodynamical simulations of galactic winds suggest that the
absorption arises in a collection of dense clouds entrained in the hot wind
and/or in shells swept up by the outflow. It seems likely that outflows would
also give rise to DLA absorption when seen in absorption against a background
QSO. It is emphasized that some differences are expected between the properties
of DLA systems in the emission weighted galaxy spectra, which always probe the
centers of star formation, and those in random sight lines through the outflow.
The observed LBGs alone can account for all DLA absorption at z ~ 3 if the
cross section for DLA absorption is pi*r^2 with r = 19 h^{-1} kpc. If the cross
section is smaller than this, then the fraction of DLA systems arising in
outflows could still be significant if there are many wind-driving galaxies
below the current detection limits. This is certainly possible since the z=3
luminosity function is still rising down to the detection limit of 0.1 L_star
and observations and simulations of local dwarf galaxies indicate that many of
these fainter galaxies drive winds as well.
