What do "strainers" refer to in swiftwater terminology?

In swiftwater terminology, "strainers" refer to obstacles that trap objects but allow water to flow through them. This concept is crucial for understanding the dynamics of swiftwater rescue operations.

Strainers can be natural or man-made structures, such as downed trees, submerged rocks, or debris piles in a river. While water continues to pass through these obstacles, any object, including a person or equipment, can become entrapped, posing a significant risk during rescue efforts. Recognizing the presence of strainers is essential for rescuers, as they must navigate around these hazards to ensure safety for themselves and those they are trying to assist.

Other options describe either incorrect characteristics of strainers, such as completely stopping water flow or being filtering devices, or refer to equipment that is not related to the specific definition of strainers in the context of swiftwater environments. Understanding the true nature of strainers is vital for effective swiftwater rescue training and practice.