A 12-mile stretch of the Mississippi River is closed this morning after a tugboat collided with an tanker, causing thousands of barrels of diesel oil on a barge to spill into the waterway. No injuries were reported in the crash, according to Coast Guard Petty Officer Jaclyn Young. But morning commuters in the French Quarter and other parts of the city should expect a heavy smell of fuel in the air. Residents in Algiers, Gretna, St. Bernard Parish and Plaquemines Parish are also being asked to conserve water, as water intakes for those communities were closed to prevent contamination of the drinking water supply. The water flowing through the tap is from reserve supplies, which could run in many areas out by afternoon or early evening, officials said. The spill did not affect the east bank water system. ...