MOVING WATER

Safety on the water depends on developing respect for the power of water. The power of current is very deceptive and should be taken into account by all boaters. A strainer is an obstruction in the water that allows water to pass through but will hold and trap boats and boaters. Rivers and rapids are rated with the International Scale of River Difficulty (Classes I - VI) which is a guide established by the American Whitewater Affiliation. Parts of rivers could have a different class rating than the overall river's rating. The rating for any river will vary as water flow increases or decreases because of seasonal conditions.

LARGE BODIES OF WATER

Large bodies of water such as oceans or Lake Erie provide different challenges and dangers than moving water. Large, relatively shallow lakes such as Lake Erie may develop large waves faster than deeper, similar waters. Small inland boats should not venture out on large waters such as Lake Erie.

WIND AND WAVES

The definition of wind is “moving air that is described by the strength and the direction of its source.” Wind acts on the surface of the water, creating waves. The greater the force and duration of the wind and the deeper and larger the water area, the bigger the waves will be. Large waves in big water can place small craft in danger. When crossing waves or another boat’s wake, head into the waves or wakes at an angle (45 degrees) to reduce pounding.

TIDES AND TIDAL CURRENT

Tides and tidal currents affect where a boater can travel or anchor safely. They also affect how long it takes to get to a destination, the speed needed to arrive at a given time, and the heading that must be maintained.

Tides are the vertical rise and fall of ocean water (and waters affected by the ocean) caused by the gravitational pull of the moon and sun. The moment the tide changes direction is known as “slack water.” “High tide” is the highest level a tide reaches during ascending waters, and “low tide” is the lowest level a tide reaches during descending waters.

The tidal cycle is the high tide followed approximately 6 hours later by low tide (two highs and two lows per day). The tidal range is the vertical distance between high and low tides. The tidal range varies from one to 11 feet in Pennsylvania on the Delaware River. Boaters should consult tide tables for times of high and low tides.

Dams on our rivers aid navigation, produce power, and prevent flooding. Stay clear of dams! Dangerous currents above the structure can draw boats into water going over or through a dam. Areas below a dam are extremely hazardous to boats because of strong recirculating currents and turbulent waters.

The most dangerous hazard on a river is a low-head dam. There are hundreds of such dams on rivers and streams throughout Pennsylvania and they are true “drowning machines.”

Water going over a dam creates a back current or undertow that can pull a boat into the turbulence and capsize it. This hydraulic can trap and hold a person or boat. Many dams are not marked and are almost impossible to see from upstream.

State law requires that many low-head dams in the Commonwealth be marked with signs and, when practical, buoys upstream and downstream from these dangerous structures. The signs detail restrictions for boating, swimming and wading, and hazards posed by the dam. Restrictions are enforced by Commission Waterways Conservation Officers. Dams must be avoided and may be located by checking water trail guides or other maps.

More information about hazards on the water.