(Portland, OR)  --  The Portland Bureau of Environmental Services is warning the public to avoid contact with the Willamette River following a major sewage overflow.  The bureau says heavy rain on Saturday caused about 60-thousand gallons of combined sewage to overflow into the river at Northwest 110th Avenue and Northwest Front Avenue.  Officials say the overflow is comprised of about 20-percent sewage and 80-percent stormwater.  Residents are advised to avoid contact with the river around the Port of Portland Terminal Four and Linnton through today.