(Happy Valley, OR)  --  The man who's accused of hitting three construction-zone workers in Happy Valley and killing one is charged with manslaughter.  Fifty-one-year-old Fedsot Tsopko is also facing a DUII charge in the Tuesday crash that killed 48-year-old Pablo Dominguez-Amezcua  of Portland.  The wreck happened on Southeast 122nd Avenue between Sunnyside Road and Mountain Gate Road.  Two other workers were hospitalized, and both are recovering from non-life-threatening injuries.