Reporter's notebook by NBC News' Charles Hadlock

The last time I visited the Rio Grande was during a rafting trip 25 years ago.  My friends and I floated on 18-foot raft boats, camped at night along the riverbank and enjoyed the peaceful water that separates Texas and Mexico.

In a scene reminiscent of the movie "Fandango," we even buried a $100 bottle of Dom Perignon in the rocks above the riverbank and swore we’d be back someday to find it and celebrate.

So much has changed along the Rio Grande since then.  Today, you’re more likely to find bales of marijuana floating on the river than tourists in raft boats.  The river is now the thin red line, the watery border that separates Mexico’s drug war from U.S. citizens who live just north of the river.

Drug runners on the Mexico side routinely launch flat-bottomed boats loaded with marijuana or cocaine, hoping to make the 15-second ride across the water to the Texas side with no one noticing.  Or, they’ll put bales of drugs into the water one by one and let the river’s current carry them to the Texas side, where they are scooped up by smugglers, loaded into trucks and hauled to places like Dallas, St. Louis and Chicago.

If the smugglers happen to be spotted and are chased by police, their favorite escape route is back to the river, where they drive the vehicles, which are often stolen, right into the water.  But the smugglers don’t just swim to get away, they try to take as much of the drug haul back with them or else the cartels will punish them or their families.  Long stretches of the river are not a safe place to be anymore.

Police on the U.S. side can only stand on the riverbank and watch.  Texas does not have boats big enough or fast enough to stop and capture the drug runners.

Until now.

This summer, I rode along with a group of state troopers from the Texas Department of Public Safety on one of their brand new boats. It’s 34 feet long, bristling with six .30-calibur machine guns that can each fire 900 rounds a minute.  The boat is powered by three 300 horsepower engines and can reach speeds of 50 m.p.h.  Texas is buying six of them to patrol the Rio Grande.  Each of the boats, equipped with armor plating, night vision equipment and sophisticated communications gear, costs about $580,000 in state and federal funds. They look like gunboats in a war. 

The Texas DPS used to rely on Texas Parks and Wildlife boats, or Border Patrol. Now they own the largest, fastest boats on the river. Currently, crews are being trained and four of the new boats will be deployed permanently later this summer. By the end of the year, all six boats will be in use. 

Texas police hope it’s enough to keep the Mexican drug war from spreading north of the border.

The river has changed a lot in 25 years.  I think I’ll let that bottle of Dom Perignon stay where it is.