The Chihuahuan Desert is the largest desert in North America and home to millions of people and species found nowhere else in the world. Neither people nor wildlife in the desert could live without the rivers that flow through it – the Rio Conchos and the Rio Grande.
But these once mighty rivers are under threat.
WWF has been working in the region since 1997 – primarily along the Rio Conchos, the biggest tributary to the Rio Grande and the river that offers greatest hope of restoring river flows.
I travelled to the region in late 2011 to get a better understanding of the issues at hand, and work with my Mexican colleagues to explore our strategies in the light of increasing threats – an increasing population, agricultural and industrial expansion and climate change.
This is the first of my five days in the field:
I get my first sight of the Rio Conchos as we leave Chihuahua City. Or, to be more precise it’s one of its tributaries, the Chuviscar. Sadly it’s no more than a dirty trickle running through a concrete storm drainage channel.
With over 90% of the Rio Conchos’ water used for agriculture, the main stresses on the river are not of urban origin. But this sight is a timely reminder that water is a precious commodity for a whole range of water users – and inadequate management has severe consequences for people and for wildlife.
Soon enough, though, I’m buoyed by the beautiful expanse of open deserts that stretches out before me as I journey towards Ojinaga on the border with the United States.
The Chihuahuan desert is ‘rain shadow’ desert, created as massive mountain ranges to its west and east block flows of moist air from the Pacific and Atlantic oceans.
Most of the year it’s a dry and inhospitable place, with water in very short supply. But in September – the month I’m here – the desert often turns green, after intense rainfall between June and August.
But this year, the rains haven’t arrived yet. Only 20% of the expected rainfall, a meagre 4cms, has been recorded this year.
Despite this, I find the desert an enchanting place – eerily silent, and with rocky outcrops and drought-resistant plants, like the oddly shaped ocotillo cacti, punctuating the landscape.
After lunch, the first real sight of water. As we turn a corner on the dust track a vast deep blue lake contrasts sharply against the dusty white desert mountains.
It’s quite a beautiful sight, but is in fact a manmade feature – the Luis L. Leon reservoir. The Luis L. Leon dam was completed in 1968, partly to irrigate farmland downstream, but largely to secure and release water for the 1944 Water Treaty that Mexico signed with the US. Under this treaty Mexico is obliged to deliver a not insubstantial amount of water from each of its tributaries into the Rio Grande.
Between 1994 and 2006, successive droughts meant that Mexico built up a huge water debt with the US. This year there should be enough water in the reservoir to deliver on the agreement – but with no rain this summer, people are very worried about next year.
An hour further downstream we meet the Rio Conchos again as it cuts spectacularly through the Peguis canyon. It’s an amazing sight and a reminder of the power the river once had.
Our final destination for the day is a lodge in the middle of the Big Bend national park on the US side of the border. Arriving there involved crossing the Rio Grande to the small town of Presidio in the US. Somewhat unaccustomed to having British people crossing overland, the immigration procedures take longer than anticipated but eventually I’m allowed to pass.
Before this we’d stopped briefly to take a look at the confluence between the Rio Conchos and the Rio Grande. With the classic Duran Duran song ‘Rio’ playing in my head, the meeting of the rivers was, I have to say, quite an underwhelming experience.
As it meets the Rio Conchos, the Rio Grande is barely more than a couple of metres wide – its water consumed upstream by agriculture and by big urban centres like El Paso. Indeed, well-respected environmental journalist Fred Pearce on confronting the same vista, concluded that “for all practical purposes the Rio Grande downstream of Presidio is in fact the Rio Conchos”.
I’m left in no doubt that keeping the Rio Conchos flowing is of paramount importance.