The stars shine bright as a cliff over the Rio Grande in the Lower Canyons of West Texas catches the first light of the rising moon. Photo by Jessica Lutz
The stars shine bright as a cliff over the Rio Grande in the Lower Canyons of West Texas catches the first light of the rising moon. Photo by Jessica Lutz.

I was lonely and nervous camping on an island of gravel in the Rio Grande. In the next few days I would solo paddle 100 miles through some of the most popular drug and gun trafficking corridors between the United States and Mexico. I called my brother on my cell phone to pass the time and ease my nerves.

From Eagle Pass to the first bridge of Laredo, the Rio Grande cuts a meandering corridor though limestone bedrock and gravel soils. Paved roads are scarce. Electricity is rare. There are no towns. The lack of infrastructure makes it difficult to patrol and easy to hide. Border Patrol agents told me the river along this stretch is beautiful, and also a smuggler’s paradise as it slips by cliffs and weaves between islands.

According to a map released this month by the National Park Service, pictured below, it is also one of the quietest places in the country. Nighttime satellite images by NASA show it is one of the darkest.

Noise map courtesy of the National Park Service's Natural Sounds and Night Skies Division.
Noise map courtesy of the National Park Service’s Natural Sounds and Night Skies Division.

The NPS noise map is based on 1.5 million hours of noise measurements gathered from more than 500 locations across the United States. The data was compiled by the NPS’ Division of Natural Sounds and Night Skies and processed along with background data such as climate, moisture levels and vegetation cover. The program then generated a map of the United States showing the noise level on an average summer day. Wet areas with lots of vegetation and wind tend to be louder than dry areas with little vegetation. The East tends to be louder than the West.

But the largest factor if an area is loud and bright are people. Cities have the most of both. Desolate deserts have the least.

The map is a step in helping scientists understand how the world is changing as people make it a louder and brighter with expanding roads, cities and industry. It was presented earlier this month at a meeting of the American Association for the Advancement of Science in San Jose, California.

Studies have already shown that many species avoid loud areas. Noise interferes with basic functions like a bat’s ability to hunt via echolocation or a frog’s chances of attracting a mate via croaking. Light pollution is changing what time songbirds start to sing. It confuses migrating birds, insects and fish and newly hatched sea turtles.

Over the last five months of traveling the Rio Grande for a journalistic undertaking I had become ever more aware of the ambient light and sound. I had traveled through some of the darkest and quietest places in the country, including Big Bend National Park and the San Juan Mountains in Southern Colorado.

Sunrise and sunset framed my daily schedule. Days on the river were spent with vigilant attention paid to any change in the sound of the river. Approaching rapids and cascades sound very much like busy highways or low flying jets. I would often prepare for one and find the other.

Light pollution from Albuquerque competes with the light of the Milky Way over a campsite along the Rio Grande in northern New Mexico. Photo by Erich Schlegel.
Light pollution from Albuquerque competes with the light of the Milky Way over a campsite along the Rio Grande in northern New Mexico. Photo by Erich Schlegel.

At night, changing river levels and weather patterns were marked with shifts in the background noise. Something you did not hear until it changed. Approaching swarms of mosquitos were announced with a prelude of a soft buzz. I could only pick up those cues in the quietest of places. In the cities they were lost to the constant background noise of people living their everyday lives. Having just left the flashing lights and cacophony of chiming bells, clicking machines and blaring soft rock music at the Lucky Eagle Casino on the Kickapoo Reservation, my senses were dulled.

I found the island as the sun was setting. Now camped in the dark, every noise I heard was muffled by the gurgling of water and unidentifiable. My imagination ran wild. The clearing of gravel I lay on became part of a cocaine and firearms superhighway. The rustling of the cane was drug-running scouts coming to check out my camp.

And there I was in the middle of it talking loudly into my brightly glowing iPhone. I told my brother I had to go and turned off every electronic device. They all had some sort of flashing light and/or ability to make a buzzing noise. Then I stayed very quiet, watching the Milky Way float slowly and silently across the night sky.

 *Featured/top image: The stars shine bright as a cliff over the Rio Grande in the Lower Canyons of West Texas catches the first light of the rising moon. Photo by Jessica Lutz.

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Colin McDonald

Former San Antonio Express-News water and environment reporter Colin McDonald traveled the length of the Rio Grande to report on climate change as one of the worst droughts ever recorded continues. He...