By Allegra Mount
Many of us in the southwest are familiar with the term “arroyo” – a Spanish word for the dry, sandy washes and gullies that have replaced most of our desert riparian areas. During our intense desert rainstorms, water rips down these steep-sided canyons, cutting and scraping away earth. The term really took root with the 19th century settlement of the southwest, a time when native grasslands, woodlands, and riparian areas suffered from resource overuse. Erosion accelerated and rivers ran dry. Our modern cities and burgeoning populations have only hastened these processes, resulting in the large-scale degradation of our aridlands ecosystems. For the past 200 years, humans have undeniably been the cause of significant problems.
At Borderlands Restoration, our work demonstrates that humans can be the solution – and on the human scale. Groups of motivated workers with hand tools can crawl up sandy washes and, with the simple action of stacking rocks, repair gullies that could never be reached by heavy machinery. We assemble people of all ages and sizes to build rock structures called Trincheras, Zuni Bowls, and Media Lunas – piles of rocks, stacked strategically to slow the flow of water. The approach is simple: the longer it takes for the water to reach its final destination, the more time it has to soak into the ground, providing crucial resources to plants and animals. The strategy is broad: build small, simple structures in great numbers and across entire regions. You don’t need a degree or a bulldozer to contribute – just a sun hat, a pair of gloves, and the motivation to work hard. To help muster the latter, it always helps to go with friends.
If you don’t start out with friends, chances are good that after 8 hours of stacking rocks together in the heat of a June afternoon, you’ll end up with some. Such was the case with a group of students and professionals working in the Chiricahua mountains this summer. Douglas high school students and professionals from Borderlands Restoration, Sky Island Alliance, the U.S. Forest Service and many other organizations spent 1 month building these same structures on the Bar Boot Ranch. 150 people-hours resulted in 42 structures. Since then, the monsoon rains have held up their end of the bargain, and our work has produced dramatic results after only one wet season.
The same trinchera, after construction in May (left) and September (right).
In looking at the before and after photos, one of the most striking changes is the increased density of vegetative cover. This is most apparent immediately upstream of each structure. Imagine the physical movements of the water down the channel – falling on the ground, picking up sediments, moving downhill and picking up speed, and then splash!, it hits a Trinchera and much of its energy is dissipated by the rocks. Still for a moment, the water spreads out along the banks and soaks into the ground, vitalizing the bank of seeds held in amongst the dirt. Then, it’s time to move on – it spills over the top of the rocks, or finds its way through the cracks, and repeats the process 50 ft. downstream when it encounters the next structure.
It follows, then, that these structures increase soil moisture most significantly in their immediate vicinities. They become refugia, or safe havens, for biodiversity, encouraging seedling establishment and creating ephemeral pools for wildlife. The return of vegetation in turn strengthens the structure’s ability to protect against erosion by holding the soil in place. Targeted restoration plantings can increase this value even further by encouraging the rapid reintroduction of nectar and fruit-producing plants of high value to pollinators, birds, and other wildlife.
At El Coronado Ranch, hundreds of rock structures have raised the groundwater up to 10 ft. This trenchera (left) now holds small pools of water year round – even at this small scale, it is a crucial water resources for wildlife. They also support plants like this Bouvardia ternifolia (right), that provides critical nectar resources for hummingbirds during the driest, hottest parts of the year.
Returning to our restoration sites to monitor and document the successes and failures is a crucial and enlightening part of our restoration work. It becomes immediately apparent that when we work in concert with natural systems, the impact of each effort increases exponentially. These structures will continue to restore the Bar Boot for years to come, with little to no additional effort on our part.
Here at Borderlands Restoration, we are privileged to call the cycles of nature our partners in restoration. We are working with nature to create strong, resilient systems that will support people and wildlife. Being nearly mid-spring, we expect that our friend the monsoons to be still a few months out. In their absence, we are strategizing, monitoring, and organizing, so that we’re ready to engage an even larger population in stacking rocks, making connections, and restoring land in the seasons to come.