By Colin McDonald

Like many Western waterways, the Rio Grande sometimes seems closer to a complicated, engineered plumbing system than a river.

Its sporadic (and often nonexistent) flows are the result of growing demand, changing climate and the ideals of the 21st century running head on with a river managed by 19th century laws and controlled by 20th century dams and ditches.

It's also a wonderful place to paddle.

On June 20, I started following the length of Rio Grande by foot, kayak, canoe and raft. I've traveled about 1,200 miles from the snowfields and burned spruce forests of Colorado's San Juan Mountains, and I'm currently 600 miles from my destination: the sunbaked sand of Boca Chica Beach and the Gulf of Mexico.

Along the way I've been talking to ranchers, farmers, biologists, engineers and anyone else with ties to the river in an attempt to understand how changes to the Rio Grande are impacting the people and places along it.

I've also had the opportunity to float some of the river's most beautiful wilderness sections with river guides and water policy experts. In October, I was joined by 13 paddlers to check out some 80 miles of the Rio Grande between Big Bend National Park in Texas and the protected areas of Cañón de Santa Elena and Maderas del Carmen in the Mexican states of Chihuahua and Coahuila.

It is a rare reach where international cooperation is more prevalent than bickering, border patrol agents are seldom encountered, and there are no dams or diversions.

Here, the Milky Way makes regular nightly appearances, cell phones don't work and time is recorded in millions of years by the limestone layers of the 1,400-foot cliffs of Mariscal Canyon.

Our group consisted of four guides who had more than 100 years of experience on the Rio Grande between them. They started their careers in the 1980s when 16-foot rafts were the vessel of choice because the river was consistently high enough to float them.

"We never thought there would be a day when we could not put a big old raft on the river and do whatever we wanted," said guide Mike Long, who has worked on the Rio Grande since 1986.

Today, an increased population and associated water demands as well as a warming climate have made inflatable kayaks and walking the riverbed the most reliable modes of river travel.

The nine clients on the trip were not your usual commercial river running clientele but a motley group of paddlers who'd racked up first descents from China to California and kayaked on every continent other than Antarctica. They surfed their loaded canoes on standing waves just to see if they could and shot the rapids backwards to make the Class II-III moves a little more fun.

Key among them was Dan Reicher, now a board member of American Rivers. He brought along fellow board member Fred St. Goar and American Rivers President Bob Irvin.

In 1977, Reicher and three classmates from Dartmouth College traveled the length of the Rio Grande by kayak, bicycle and canoe as part of an expedition sponsored by the school's Ledyard Canoe Club and National Geographic.

Even then, the river was not in great shape; they saw lots of mud and a riverbed so dry it often made more sense to paddle the irrigation ditches.

Still, there was water for most of their journey and there was no border wall or issues with crossing from one bank to the other.

"We paddled the length of the Rio Grande in a very different time, when water was more plentiful, cities and farmers less thirsty, and the border less of a fortress," Reicher said. "How quickly things have changed as temperatures–and tempers–have risen along the river."

Even on this remote reach, the water is now too salty to drink and is listed as impaired by the state of Texas and the EPA. Invasive cane dominates the riverbanks. The low flows of the last two decades have failed to flush the gravel bars and riverbanks. Almost everything along the river is now covered in layers of fine sediment and mud that can reach 15 feet high.

The river's most basic function as a conveyor belt to haul earth towards the sea is broken, explained local geology professor Kevin Urbanczyk. The river is literally choking on its own sediment.

But we lucked out. After five years of drought, hurricanes and a strong monsoon season had filled reservoirs in Mexico. The river was running deep and smooth when we arrived.

On the water, the crew unwound. We swam, skipped stones and relished the solitude as we explored side canyons and studied rock art.

Floating between sheer cliffs that gave no indication of which country claimed them, there was no doubt the Rio Grande was still a river.

It took some four million years to carve these canyons. The recent complications from dams, dredging and diversions will pass.

And there is a chance the river may start coming back in our own time as well.

"There is always hope for rivers," American Rivers President Irvin told me as we watched the river flow by our camp. "Even if we have dammed them, polluted them or diverted them, the river is still there."

We just have to decide what we want to do with it.

Read C&K’s interview with McDonald and see another photo gallery from the Rio Grande source to sea.

Track McDonald’s progress and read his blog posts.