BOQUILLAS CANYON, Mexico – Victor Valdez doesn't need a microphone to sing. His voice echoes off the steep canyon walls that surround his unusual stage here. Standing knee-deep in the middle of the Rio Grande's rushing waters – at the dramatic entrance of the Boquillas Canyon – Mr. Valdez belts out heart-felt ballads such as "Cielito Lindo" and "El Rey." His baritone voice floats through the canyon and up the Rio Grande toward Big Bend National Park.

ERICH SCHLEGEL/DMN

From the middle of the Rio Grande, Victor Valdez sings ballads that drift toward Big Bend National Park.

"This canyon is my stage," Mr. Valdez added. "And I have the best theater along the border."

He sings, he said, to remind people that this Boquillas del Carmen community, on the northern edge of the Mexican state of Coahuila, is alive.

Mr. Valdez's singing seems to be one of the few things keeping Boquillas humming, amid tough U.S. border security measures that have turned this once-vibrant village into a ghost town.

He sings for tips. And with each donation, he's able to help sustain life for the few residents, including a 94-year-old man and his family; a mother in a wheelchair with a husband in jail and an 8-year-old daughter; and two helpers who serve as lookouts for the U.S. Border Patrol, or Park Rangers. They all split the earnings.

"Victor is Big Bend's singing angel," said Cynta de Narvaez, who co-founded a group called Fronteras Unlimited to aid Boquillas residents. "He embodies the spirit of giving and sharing, and that practically makes all the difference."

Mr. Valdez's singing reflects the reality of Boquillas del Carmen and dozens of other small communities along the 2,000-mile border. They were created as mining towns by American entrepreneurs at the turn of the century. In Boquillas, Mexican miners would fill buckets with minerals and put them on cable trains and transport them to the U.S. side.

The two sides were intractably linked. There was no formalized immigration, or customs checks. Mexican firemen, known as the Diablos , would rush across the border to put out fires. On holidays, residents would crisscross to exchange gifts.

Today, visitors to Boquillas del Carmen are few.

A small group of Texans occasionally spearheads aid through a flotilla of rafts on the Rio Grande. To avoid breaking immigration laws, volunteers stay on the river, avoiding the banks or setting foot on Mexican soil. They deliver turkeys for Thanksgiving and piñatas for Christmas.

"It's hard because it's as though our family is on the other side of the glass wall," said Danielle Gallo, a Marathon resident and former Big Bend firefighter who taught English to Boquillas schoolchildren. She and Ms. de Narvaez started www.fronterasunlimited.org to aid residents.

ERICH SCHLEGEL/DMN

Cynta de Narvaez follows Victor Valdez through the desert to the entrance of Boquillas Canyon.

"We can see them, but we can't touch them," she said, "We can't celebrate the holidays with them. We always did, and now we can't. Our family must rely solely on their creativity to survive."

In fact, Mr. Valdez said singing was never his passion. He was a river guide, a boatman, who for more than 40 years picked up tourists and transported them across the river to his hometown of Boquillas del Carmen. There, tourists shopped, sipped a cold beer and often stayed at a bed and breakfast before being ferried back across to the U.S. side. Mr. Valdez earned $2 per passenger.

The crisscrossing ended shortly after the Sept. 11, 2001, terrorist attacks, and the population dropped from about 400 to some 70 people.

"On May 10, 2002 – that painful day will always be etched in my memory – the Border Patrol came and told me the border was closed forever," Mr. Valdez recalled as he stood in the middle of the river. "I thought my life was over. Suddenly we weren't neighbors anymore, but viewed as strangers, even terrorists. Our worth to them was over."

Mr. Valdez and his wife left Boquillas promptly and headed to the closest Mexican city, Melchor Muzquiz, some seven hours away by bus. There, he worked 12-hour shifts as a cook – for less than $10 a day.

But he missed the beauty and wild of the Big Bend. He missed his birthplace, where he had spent most of his 56 years.

Homesick, he returned alone after a few months and joined the few locals in making handicrafts, including colored walking sticks, scarves, copper scorpions and quilts. Some of the locals quietly place the trinkets along hiking trails. They put up cans to solicit donations from tourists and then sneak across the border to pick up any change.

Mr. Valdez picked the last stop on the Boquillas Canyon and Mexican ingenuity took over – with a gentle push by a Border Patrol agent who, with a wink-and-a-nod, encouraged tourists like 21-year-old Sul Ross State University student Nora Franco to donate a few dollars.

"He makes my heart melt," she says.

Mr. Valdez simply reiterates, "Out of desperation I started singing. But I realized that being right up against the canyon was actually a blessing. Praise the Lord," he added. "My voice suddenly boomed. But if they put up a fence here, not even a miracle from God will help. Silence will fill these canyons."

Suddenly, Mr. Valdez breaks into song and his voice echoes across the canyons. Big Bend comes alive.