(Portland, OR)  --  Environmental crews are mopping up after thousands of gallons of sewage spilled along Northeast Marine Drive.  The Portland Bureau of Environmental Services says a valve malfunction caused more than 18-thousand gallons of sewage to leak from an underground pipe located at 112th Avenue near the I-205 yesterday.  The agency says they were able to prevent the sewage from running into the Columbia River.  Officials say most of the sewage spilled into a ditch and that the Marine Drive bike path was not affected by the spill.