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We present optical spectra of QSO HS~1946+7658 with either high resolution(FWHM=10 km/s) or high signal to noise ratio (SNR=40-100). We find 113 Lymanalpha and six metal line systems. The metal systems at Zabs=2.844 and 3.050have complex velocity structures. We find that the system at 2.844 is a dampedLy-a absorption system, with neutral hydrogen column density oflogN(HI)=20.2+/-0.4, and it is the cause of the Lyman limit break at 3520\AA.The metal abundance in the gas phase of the system is [M/H]=-2.6+/-0.3, with abest estimate of [M/H]= -2.8, with ionization parameter Gamma=-2.75, from aphotoionization model. We show that the abundance ratios rule out appreciabledust in this DLA system. We do not see the enhancement of O over C reported inNature by Reimers last years. We see CII*(1335) offset by 15 km/s with respectto CII(1334), presumably because the gas density varies from 2 - 8 cm(-3) withchanging velocity in the DLA system. These densities imply that the dampedcomponent is 6 - 25 pc thick, which is reasonable for a single cloud in a coldspiral disk. We see a 2.6sigma lack of Ly-a forest lines well away from the QSOredshift, which may be a chance fluctuation. We also see a correlation betweencolumn density N(HI) and Doppler parameter b for 96 unsaturated Ly-a forestabsorption lines, and although this correlation persists in the 36 Ly-a lineswhich lie in regions where SNR=8-16, we agree with Rauch etal (1993) that it isprobably a bogus effect of low SNR. We show that there are few low-b Ly-aforest lines in moderate SNR data.Comment: (Plain Tex, 46 pages and 21 figures. To get 21 postscript files for  figures ftp to 132.239.146.152 and login as ftp in directory /pub/fan). To  appear in the Astrophysical Journal Supplement

Lick optical spectra of quasar HS 1946+7658 at 10 kilometers per second resolution Lyman-alpha forest and metal absorption systems