Pictured here is a typical gully. It was caused by a road which triggered an upward-moving headset. How can you tell an active gully? Whenever the sides of a gully are vertical, the gully is unstable. These drain pastures and ‘bleed’ moisure out of the water table on both sides. This dries soil and leads to bare ground.
Throughout the desert Southwest, after bad grazing practices, misplaced roads are the main cause of erosion on most ranches. When it rains, these channel water away from grass and range.
The headcuts can do massive damage.
Headcuts can literally eat whole valleys.
This beautiful stand of Giant Sacaton is bisected by a substandard county road. The road is below grade and has created the headcut shown just above. The cut is moving steadily toward this spot and unless stopped, will eat through here.
When it rains, the gullies run deep, and erode pasture.
Thousands of acre-feet of water never get to irrigate the desert grassland: the result is brush encroachment followed by bare ground.