|
Dry valleys look similar to ordinary river valleys, but without any stream flow. They are not exclusive to karsts; many regions contain short dry sections at the head of a valley. Dry valleys can be longer and form branching systems on other permeable rocks such as pumice or sandstone, but they are usually developed more extensively in karst rocks. A good example of a dry valley occurs when a river enters a karst from an impervious rock, and then sinks, but the dry valley continues through the karst. In extreme flood conditions, water may rise at various locations in the dry valley indicating subsurface flow.
|
