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Show PART II NATURE, USE AND MANAGEMENT OF WATERSHED LAND Rock outcrop, boulders, stones, and cobbles on the soil surface may physically limit the application of watershed treatment measures. Soils dominated by rock outcrop and coarse fragments are most common around mesas, along canyons, and on mountain slopes. Geology and topography Geology and topography have greatly influenced the occurrence, behavior, and chemical quality of water resources within the region. They have also determined the characteristics and distribution of the parent materials in which soils have formed. Consequently, they are vital components in watershed planning, use, and treatment. The region is characterized by diverse topography including steep mountains, broad plateaus bounded by step-like benches and escarpments, smooth plains and river valleys, gently sloping ridges, and rough-broken badlands. In parts of the region deeply incised canyons are a distinc- tive feature. Some of the larger streams flow through broad valleys and are bordered by extensive areas of nearly level land. Other gently sloping lands are chiefly on the plateaus and mesas. Contrasting topography of mountain slopes 11 |