  We present results from two projects in which we have used the HI 21cm
emission line as a tracer of gas-rich galaxy populations in the vicinity of
Lyman-alpha absorbers. In the first case, we examine the HI environment of SBS
1543+593, the nearest damped Lyman-alpha absorber. We use a VLA map of the
region around this LSB galaxy which itself shows an extended HI disk to
identify 3 gas rich neighbors within 185 kpc. While it is not clear whether we
should expect local damped Lyman-alpha systems to reside in such gas-rich
regions, we would expect this kind of environment to be more prevalent at
higher redshifts where less of the gas is in the dense inner regions of
galaxies or has been consumed by star formation. This local galaxy is the only
system in which we can study the gaseous environment in this kind of detail. In
the second case, we examine the HI environment surrounding 16 Lyman-alpha
forest absorbers along 4 QSO sightlines. We do not detect any gas-rich galaxies
at the absorber positions indicating that, at least down to our sensitivity
limits, these absorption lines do not seem to be associated with galaxy halos.
For half of the Lyman-alpha absorption systems there is a galaxy within 500
kpc, but for the other half there is not. In two cases there is no galaxy
within 2 Mpc of the Lyman-alpha absorption systems indicating that absorbers
do, in some cases, reside in voids.
