A bird watcher trudges along the seaweed soaked beach near the mouth of the Rio Grande. He's huffing and sweating, but is determined to reach his destination.
Once he gets there, the binoculars dangling from his neck won't be used to spot rare species of bird. He's after an even rarer sight - a river to nowhere.
The Rio Grande has ceased to flow into the Gulf of Mexico for the first time in recorded history.
After almost 2,000 serpentine miles through Colorado, New Mexico, and Texas, the mighty river stops 500 feet from the shore - a testament to the Dust bowl-size drought in South Texas, rapid population growth on both sides of the border, and an infestation of exotic weeds.
The silted-shut river is causing serious problems with everyone from shrimpers to ranchers. But it is also attracting a new kind of tourist.
"People come all the way out here and ask, 'Is it true that the river doesn't reach the ocean anymore?' " says a US Border Patrol agent stationed here on a recent day.
The Border Patrol mans the dried-up river bottom 24 hours a day, not only to catch smugglers now able to walk across the border, but also to warn US visitors. "Winter Texans come down here and just keep going, unaware that they're crossing into Mexico," the agent says.
Spanish explorers used to come to the banks of the Rio Grande to marvel at its size and strength. It was once described as a farther than a musket shot wide and 30 feet deep. It had many names, from Rio Turbio (Turbulent River) to Rio Caudaloso (River Carrying Much Water).
Today, it might be called Rio Wimpy. Its status is a testament to the vagaries of nature and the delicate balancing act that comes with doling out the US's limited water resources.
"At a certain point, demands on our rivers get too high, and they can't take anymore without being destroyed," says Larry McKinney of the Texas Parks and Wildlife. "This is a warning shot for us."
Why the river of sand
While population growth on both sides of the border is responsible for some of the river's problems, the weather is the main culprit. The Rio Grande Valley routinely experiences drought conditions. But the latest one - now eight years old - is a once-in-a-century event.
"I think when this drought ends and the numbers finally come in, we are going to find that this is the new drought of record," says Gary Powell with the Texas Water Development Board. "We are in dire straights."
Weeds, too, are a problem. Hyacinth, an ornamental plant, floats on the surface and dangles roots deep into the water.
Another non-native plant, hydrilla, grows up from the river bottom. Between them, they create walls of vegetation that run for miles, curtailing the flow of water downstream, plugging pumps, and clogging irrigation canals.
Already, officials have tried using a machine to cut a swath through them. But that simply breaks off pieces that reproduce downstream. So the US and Mexico are now tapping biology: They're stocking the river with bugs and Chinese carp, whose diet is primarily hyacinth and hydrilla.
While these efforts go on to keep the water moving, others are trying to cope with what little is left. Farmers, ranchers, commercial fisherman, and shrimpers are among the most hard hit. The Rio Grande Valley is the most fertile land in Texas, and farmers are in the middle of peak irrigation.
The length of the drought has forced many farmers to switch from high-water crops, such as sugar cane and citrus, to low-water crops, such as cotton and grain. But many fields are bare. "It's hurting," says Bob Wiedenfeld, a soil scientist at Texas A&M University. "Farmers are being forced to cut back as more and more water is being diverted to cities."
Normally, the mouth of the river is a diverse estuary for blue crabs, redfish, spotted sea trout, snook, and several varieties of shrimp. These species mature in brackish water - a mixture of salt and fresh water - before returning to the ocean. But the mouth closed before many could make it upstream.
"Very few made it in," says Tony Reisinger, a Cameron County marine agent, who's been taking samples. "There's no way to put a value on the loss, and it's a binational loss."
Shrimp can't jump
On the US side alone, the two ports near the mouth of the Rio Grande lead the state in shrimp catches. Though Gulf shrimpers are coming off a banner year, they know the drought will hurt. "Shrimp can't jump over the sand," says Wilma Anderson, executive director of the Texas Shrimp Association.
At Port Isabel, near the mouth, Walter Zimmerman oversees a fleet of 23 boats. He says shrimpers always lose out because they're not landowners with water rights. "When they don't release enough water, it messes up the nursery area," he says. "We're farmers. We just don't plant the seed."
For those who do own water rights, at least some relief is coming. Two reservoirs that supply the lower valley with water are currently 40 percent full - higher than in recent years.
Still, even with the reservoir allotments, more water is needed. "The Rio Grande is our only source of drinking water. We have no underground aquifers," says Mary Yturria, founder of the Rio Grande Institute, a nonprofit group. "We are at the mercy of the rain."
Her husband, Frank, is a prominent Brownsville rancher whose acreage dates back to the Spanish land grants. He's had to dig shallow ponds to water the cattle, but they won't last.
"Right now, I'm praying for a hurricane that brings a great deal of water and doesn't leave us devastated," says Ms. Yturria.
(c) Copyright 2001. The Christian Science Monitor