Navigating the Mississippi River at night is akin to driving with dim headlights on a dark, winding highway as the yellow and white caution lines are erased and repainted.

Add to that increasingly low water conditions and the river at night becomes a dangerous mix of unknown darkness for which no captain armed with the best maps and voyage plans can fully prepare.

“It puts a lot of stress on the guys in the pilot house,” said Tim Miller, lead captain of the Melody Golding, the flagship of Golding Barge Line.

The Melody Golding made a stop in the Yazoo River Diversion Canal on a night last week to attach an empty barge to its northbound tow, and it was with a determined concentration — the type expected more during a moon landing than river navigation — that Miller pulled into the canal.

At its deepest in the mouth of the canal, the water below the boat measured 11.6 feet, leaving little room for error for the boat’s 9-foot draft.

“The Yazoo is tight right now,” Miller said. “You can’t meet anyone in here.”

With a cargo of about 3 million gallons of gas, diesel and other petrochemicals in tow, extra caution was understandable.

“One of those guys with grain, if he spills some, it’s going to be fish food,” Miller said. “If I spill this, it’s going to be my name on Headline News.”

During low water, sand bars can be created overnight by debris that normally would be flushed out by the river current, Miller said. Darkness makes them nearly impossible to spot, even with the boat’s spotlights.

“Nothing that you’ve got can tell you where a bar built,” Miller said.

Striking exposed rocks near the shore or bridges also is a major concern, he said. Miller steered the Melody Golding under the center of the Interstate 20 and U.S. 80 bridges to avoid striking exposed rocks along his normal path between the third and fourth pylons.

A lighted buoy system signals to captains where the navigable waterway ends, but when the river rises or falls quickly, the buoys become inaccurate. Passing boats in narrow channels often strike the buoys, making them more inaccurate, Miller said.

Before and during their six-hour shift, captains scour an ever-growing log of Coast Guard warnings and river stage predictions. For this past week, the packet was about a half- inch thick. Miller had highlighted in florescent pink every trouble spot between New Orleans and Memphis.

“There are too many to name really,” Miller said.

Because conditions can change so quickly, captains rely on each other for real-time updates, and the pilot house becomes a hub of river information broadcast by email, radio and cell phones, said Rob Sadler, logistics manager with Golding Barge Line.

“It’s amazing how quickly things go around here,” Sadler said.

Low water causes towboats to travel slowly and lighten the load, especially when they are carrying hazardous cargo, Sadler said.

Through Vicksburg, the Melody Golding was traveling around 6 mph, and Miller said it had taken three days to travel from New Orleans.

“It really hurts the bottom line,” Sadler said.

Slower, lighter deliveries increase the price of gas and other products shipped on the river, he said.

The Melody Golding pushes only three barges at a time, but they are equivalent in weight and size to 10 standard barges, Sadler said. Even with the smaller load, the front of the tow is several hundred yards from the pilot house.

“When you have these guys with 36 barges, it really makes it difficult,” Sadler said.

Despite the apparent danger, few towboat accidents occur compared to hours of work, Sadler said.

In 2010, 192 incidents were reported from more than 31,000 vessels, according to the American Waterways Operations Association.

Increased danger is still prevalent until the river begins to rise, but, for now, no end is in sight for low-water conditions.

The Mississippi River at Vicksburg was at 5.1 feet Saturday, and the National Weather Service is expecting water levels to continue to drop at least until August.

The stage at Vicksburg is forecast to be 2.2 feet on Aug. 8, though stages at Vicksburg are based on a zero mark of 46.23 feet and any depth below that is recorded as a negative number.