Photograph of a grass-protected waterway. This waterway as protected by western wheatgrass takes water for more than 3 miles along a highway ditch and additional water through a culvert from a bend across the highway [?]. This grass is three-years old. This waterway must be able to carry large amounts of water and therefore be protected against erosion. Yet it must not catch silt because it must remain wide and flat. Note the playa lake [i.e., a dry lake] in the background. TX-47, 235.