Small Rock Dams
In hilly or mountainous areas transected by washes and canyons, CLO send out teams to construct loose rock structures (trinceras). Trinceras serve the purpose of slowing down the flow of water (from monsoon rains) over the earth and catching sediment that would otherwise wash away. We applied the same treatment in washes that were heavily flooded during the rainy season.
Restoration results are tied to rainfall. At first, the ground lay scarred and dormant. However, when the first significant monsoon rains come, instead of rushing over the landscape and washing topsoil away, rainwater is caught in the loose rock dams that now dot the hillsides. With each raining season, more and more soil is deposited behind the trinceras. Because the soil below and above the structures remained wet, native grasses can become established. Eventually, once latent seeds began to sprout and a blush of green can be seen extending throughout the valleys and up the sides of hills.
We have built over 40,000 loose rock dams (trincheras) over the past 30 years.