The Chihuahuan Desert is the largest desert in North America and home to millions of people and species. Neither people nor wildlife in the desert could live without the rivers that flow through it – the Rio Conchos and the Rio Grande.
I travelled to the region in late 2011 to work with my Mexican colleagues in the light of increasing threats to these rivers – a growing population, agricultural and industrial expansion and climate change.
This is the second of my five days in the field:
Having completed the last part of yesterday’s journey in the dark, it was only today, at sunrise, that I truly appreciated the spectacular beauty of the Big Bend reach.
Here the Rio Grande winds through volcanic massifs and cuts though spectacular gorges. The biodiversity is very rich here too. Mountain lions, black bears and Mexican wolves roam the higher ground. Fish species found nowhere else inhabit the Rio Grande and its tributaries. And hundreds of bird species stop here to rest on their long north-south or south-north migrations.
As a consequence, seven protected areas have been established here – three in the US and four in Mexico.
Later in the morning I meet park manager Joe Sirotnak, who explains the importance of the river to sustaining life in the protected areas.
The most important thing, of course, is to ensure enough water is flowing down the river. In periods of drought the levels of the Rio Grande have dropped alarmingly, and the wildlife in the park suffered badly. Seven fish species are already known to have gone extinct locally.
I’m beginning to understand the importance of the Rio Conchos being able to deliver enough water to meet the 1944 treaty. But, critically, it is not just about the volume of water released each year. The timing of the flows is very important too.
The water now flowing out of the Rio Conchos is heavily controlled by the Luis L. Leon dam, and bears little relation to what would naturally occur. A dramatic reduction in big flood events results in sediment building up on the riverbanks, and non-native species, such as giant cane and salt cedar, are invading. These hardy shrubs leave very little space for other types of vegetation.
Encouragingly, I’m taken to two sites where WWF – together with Joe, his team and local community members employed by us – have successfully removed these two species from around eight miles of river. Truly back-breaking work.
But it’s good to hear that we’ve been instrumental in bringing together the Big Bend National Park, the Texas Park Service and the Mexican Natural Protected Areas Commission (CONANP), resulting in a total of 100 miles of riverbanks being restored.
The next step now is to work with the Mexican Water Commission, CONAGUA, to negotiate a more natural release of water from the Rio Conchos to prevent further build-up of sediment and the narrowing of the river.
In the afternoon, I visit a wider stretch of river where sediment has been removed and the fish are thriving.