Hidden Dams and Poor Visibility
Some dams, spillways, outlet works, pipes or other structures are not marked or are not above the water level, making them difficult to identify. If in moving water, it may be difficult or impossible to identify the hazard from upstream until it is too late to avoid it. Furthermore, on lakes, rivers, creeks and other bodies of water, water levels can vary over time, sometimes rapidly. Hazardous conditions may be present at some water levels/flow rates while not present at others. The best course of action is to be familiar with your planned route, the conditions of the waterway you intend to be on and the features that may potentially be hazardous along your intended route. If a particular feature is identified as potentially being hazardous, get out of the water and scout it before deciding whether to proceed, portage or avoid it.
Some hazards are particularly difficult to identify from the water. For example, water flowing over the crest of a dam or spillway (at the horizon line) can blend in to the downstream area when viewed from upstream. This condition is often difficult to perceive visually and there may be little to no audible noise warning of the hazard. Being aware of this condition is particularly important on rivers, creeks and swift flowing water as well as around low-head-dams.
Another hazard which is extremely difficult to identify from above the water are diversion or outlet works structures and culverts. These are often hidden below the water, or may be hidden behind overgrown bank vegetation. Furthermore, there is often little to no disturbance of the water surface when these are operating. These can create strong undercurrents within the main lake or creek, pulling a person into or against them. Strong suction forces associated with these features, can also make it difficult or impossible to escape from. These structures are best avoided and given a wide berth.
Additionally, many drownings and other incidents occur when swimmers and boaters go out on the water early in the morning or late at night, when light is low or when conditions are foggy and visibility is poor. Always make sure you are aware of your route, the presence of dams or other hazards along your route and only go out on the water in high visibility, safe conditions, if possible.
Citations:
Revision ID: 4426
Revision Date: 11/18/2022