Low-Head Dams - Boat Ed

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Course Outline

  • Unit 1: Before Getting Underway
    • Topic 1: The Many Parts of a Boat
      • Parts of a Boat From a Side View
      • Parts of a Boat From a Front View
      • Activity: Can You Label the Parts of a Boat?
    • Topic 2: Types of Boat Hulls
      • Displacement Hulls
      • Planing Hulls
      • How Planing Hulls Operate
      • Descriptions of Hull Shapes
    • Topic 3: Boat Length
      • Measuring Length Overall
      • Length Classes
    • Topic 4: Types of Engines and Drives
      • Outboard Engines
      • Inboard Engines
      • Stern Drives
      • Jet Drives
    • Topic 5: Personal Watercraft
      • What Is a PWC?
      • Parts of a PWC From a Front View
      • Parts of a PWC From a Side View and Operator's View
      • Activity: Can You Label the Parts of a PWC?
    • Topic 6: Sailboats
      • Parts of a Sailboat
    • Topic 7: Your Boat's Capacity
      • The Capacity Plate
      • Example of a Capacity Plate
      • Calculating Your Boat's Capacity
    • Topic 8: Float Plans
      • File a Float Plan
      • Float Plan for Short Outings
      • Float Plan for Extended Outings
    • Topic 9: Fuel Your Boat...Safely
      • Before Fueling Your Boat
      • While Fueling Your Boat
      • After Fueling Your Boat
      • Video: Fueling Your Boat
      • Fueling a PWC
      • Prevent Running Out of Fuel
    • Topic 10: Trailering Your Boat
      • Choosing the Right Trailer and Towing Vehicle
      • The Towing Hitch
      • Trailer Safety Chains
      • Before Leaving Home With Your Boat and Trailer
      • On the Road With a Trailer
      • Launching Your Boat From a Trailer
      • Backing the Trailer Into the Water During Launch
      • Retrieving Your Boat Onto a Trailer
      • Do Not Power Load Your Boat
      • Courtesy on the Boat Ramp
      • Video: Trailering & Launching
    • Topic 11: Tying Nautical Knots
      • Types of Nautical Knots
      • Animation: Learn to Tie Nautical Knots
    • Topic 12: Taking Care of Your Boat and Engine
      • Boat Maintenance
      • Engine Maintenance
    • Topic 13: Summary
      • What You've Learned
      • Video: Unit 1 Review
  • Unit 2: Getting Out on the Water
    • Topic 1: Casting Off
      • Before Casting Off
      • Casting Off With No Wind or Current
      • Casting Off With Wind or Current Toward the Dock
      • Activity: Casting Off With Wind or Current Toward the Dock
      • Casting Off With Wind or Current Away From the Dock
      • Activity: Casting Off With Wind or Current Away From the Dock
    • Topic 2: Docking
      • Before Docking
      • Docking With No Wind or Current
      • Activity: Docking With No Wind or Current
      • Docking With Wind or Current Toward the Dock
      • Activity: Docking With Wind or Current Toward the Dock
      • Docking With Wind or Current Away From the Dock
      • Activity: Docking With Wind or Current Away From the Dock
      • Video: Casting Off & Docking
    • Topic 3: Navigation Rules: Traffic Laws of the Waterways
      • Three Major Responsibilities of Every Boater
      • Rules for Encountering Other Vessels
      • Exceptions to the Navigation Rules
      • Navigation Rules: Definitions
      • Power-Driven Vessel Encountering Power-Driven Vessel
      • Activity: Meeting Head-On—Power vs. Power
      • Activity: Paths That Cross—Power vs. Power
      • Activity: Overtaking—Power vs. Power
      • Power-Driven Vessel Encountering Sailing Vessel
      • Activity: Meeting Head-On—Power vs. Sail
      • Activity: Paths That Cross—Power vs. Sail
      • Activity: Overtaking—Power vs. Sail
      • Sailing Vessel Encountering Sailing Vessel
      • Animation: Wind on Same Side—Sail vs. Sail
      • Animation: Wind on Different Sides—Sail vs. Sail
      • PWC Encountering PWC
      • Activity: Meeting Head-On—PWC vs. PWC
      • Activity: Paths That Cross—PWC vs. PWC
      • Activity: Overtaking—PWC vs. PWC
      • Responsibilities Between Vessels
      • Video: Rules of the Waterways
      • Operating During Restricted Visibility
      • Additional Information About Navigation Rules
    • Topic 4: Navigation Lights
      • Common Navigation Lights
      • Animation: Common Navigation Lights
      • Typical Recreation Vessels' Navigation Lights
    • Topic 5: Night Navigation
      • Challenges of Navigating at Night
      • When You See a Green and a White Light
      • Animation: When You See a Green and a White Light
      • When You See Only a White Light
      • Animation: When You See Only a White Light
      • When You See a Red and a White Light
      • Animation: When You See a Red and a White Light
      • When You See a Red, a Green, and a White Light
      • Animation: When You See a Red, a Green, and a White Light
      • When You See a Red and a Green Light But No White Light
      • Animation: When You See a Red and a Green Light But No White Light
      • When You See Only a Green Light or Only a Red Light
      • Animation: When You See Only a Green Light
      • Animation: When You See Only a Red Light
      • Video: Navigating at Night
      • Towing Lights on Commercial Vessels
    • Topic 6: Sound Signals
      • Sound Signals Used for Encountering Situations
      • Examples of Sound Signals Used for Encountering Situations
      • Sound Signals Used to Alert or Warn
    • Topic 7: Summary
      • What You've Learned
      • Video: Unit 2 Review
  • Unit 3: Navigation and Safe Operation
    • Topic 1: U.S. Aids to Navigation System (ATON)
      • Traffic Signals of the Waterways
      • Video: Navigating the Waterways
      • Lateral Markers: Colors and Numbers
      • Lateral Markers: Shapes
      • Lateral Markers: Other Kinds of Buoys and Markers
      • Lateral Markers: "Red Right Returning"
      • Intracoastal Waterway (ICW)
      • Western Rivers System
      • Non-Lateral Markers
      • Common Non-Lateral Markers
      • Other Non-Lateral Markers
      • Animation: Waterway With Buoys and Markers
    • Topic 2: Anchoring
      • Choosing the Right Anchor
      • Preparing Your Anchor
      • Anchoring Your Boat
      • Allowing for "Swing Room" When Anchoring
      • Retrieving an Anchor
      • Animation: Anchoring Review
      • Video: Anchoring Your Boat
    • Topic 3: Dams, Locks, and Bridges
      • Low-Head Dams
      • Animation: Dangers of Low-Head Dams
      • Large-Structure Dams
      • Locks
      • Traffic Signal Lights at Locks
      • What Boaters Should Do When Using Locks
      • Animation: Locks Review
      • Passing Under Bridges
    • Topic 4: Changing Water Levels
      • Dangers of Fluctuating Water Levels
      • Tides on Coastal Waters
    • Topic 5: Compasses and Charts
      • Steering Compasses
      • Nautical Charts
    • Topic 6: Personal Watercraft
      • Video: Personal Watercraft: Preparing to Ride
      • Before You Go Out on Your PWC
      • Steering and Stopping a PWC
      • What Happens When You Release the Throttle
      • Video: Steering and Stopping a PWC
      • PWC Safety: Stay Aware of Traffic
      • Video: PWC Safety—Stay Aware of Traffic
      • PWC Safety: Be Aware of Blind Spots
      • PWC Safety Practices
      • Inspecting Your PWC
      • Reboarding a Capsized PWC
      • PWC Courtesy: Limit Your Noise
      • PWC Courtesy: Keep Your Distance
      • Video: Personal Watercraft: On the Water
      • Environmental Considerations for a PWC
      • Video: PWC Review
    • Topic 7: Engine Cut-Off Switches
      • How an Engine Cut-Off Switch Works
      • Use of Engine Cut-Off Switches Helps Prevent Injuries
    • Topic 8: Avoiding Jet Stream and Propeller Strike Injuries
      • Avoid Jet Stream Injuries
      • The Most Gruesome of Boating Accidents
      • How to Prevent Propeller Strikes
      • Devices That Reduce Propeller Strikes
      • The "Circle of Death"
      • Animation: The "Circle of Death"
    • Topic 9: Summary
      • What You've Learned
      • Video: Unit 3 Review
  • Unit 4: Indiana's Legal Requirements of Boating
    • Topic 1: Your Boat's Identification
      • Which Boats Require Registration?
      • Certificate of Registration
      • Displaying the Registration Number and Excise Tax Decals
      • Other Facts About Titling and Registering Your Boat
      • Boat Excise Tax
      • Hull Identification Numbers
    • Topic 2: Who May Operate
      • Operator Age and Education Requirements
    • Topic 3: Unlawful Operation
      • Reckless Operation
      • Illegal Speeds or Distances
      • Video: The Danny Hampson Story
      • Unsafe Conditions
    • Topic 4: Alcohol and Drugs
      • Video: Alcohol Can Be Deadly
      • Boating While Intoxicated
      • Blood Alcohol Concentration
      • Penalties for Boating While Intoxicated
    • Topic 5: Staying Clear of Other Boats
      • Obstructing Navigation
      • Homeland Security Restrictions
      • Video: Homeland Security
      • America's Waterway Watch
    • Topic 6: Personal Flotation Devices (PFDs)
      • Overview of PFD Law
      • Specific PFD Requirements
      • Type I PFDs: Wearable Offshore Life Jackets
      • Type II PFDs: Wearable Near-Shore Vests
      • Type III PFDs: Wearable Flotation Aids
      • Type IV PFDs: Throwable Devices (Not Wearable)
      • Type V PFDs: Special-Use Devices
      • Video: Wearing Life Jackets
    • Topic 7: Fire Extinguishers
      • Types of Fire Extinguishers
      • Requirements to Carry Fire Extinguishers
      • Number and Type of Required Fire Extinguishers
      • Keeping Fire Extinguishers Readily Accessible and in Good and Serviceable Condition
      • Fire Extinguisher Charge Indicators
    • Topic 8: Other Engine Requirements
      • Backfire Flame Arrestors
      • How Ventilation Systems Work
      • Ventilation System Requirements
      • Mufflers
    • Topic 9: Navigation Lights
      • Overview of Navigation Lights Law
      • Required Lights: Power-Driven Vessels Less Than 15 Horsepower
      • Required Lights: Power-Driven Vessels 15 Horsepower or Greater
      • Required Lights: Unpowered Vessels More Than 22 Feet in Length
      • Required Lights: Unpowered Vessels 22 Feet in Length or Less
    • Topic 10: Waters of Concurrent Jurisdiction
      • Which Waters Have Concurrent Jurisdiction?
    • Topic 11: Signaling and Sound Devices
      • Requirements to Carry Visual Distress Signals (VDSs)
      • Pyrotechnic VDSs
      • Non-Pyrotechnic VDSs
      • Combinations of VDSs That Meet Requirements
      • Requirements to Have Sound-Producing Devices
      • Common Sound Signals
    • Topic 12: Additional Regulations and Safety Considerations
      • Diver-Down Flags
      • VHF Radio
      • Marine Events
      • Courtesy Equipment Inspection
    • Topic 13: Personal Watercraft
      • Requirements Specific to PWC
      • Operating a PWC
    • Topic 14: Skiing and Tubing
      • Requirements to Tow a Person With a Vessel
      • Skiing or Tubing on the Ohio River
    • Topic 15: Waste, Oil, and Trash Disposal
      • Overview of Pollutant Disposal Laws
      • Discharge of Sewage and Waste
      • Discharge of Trash
      • Discharge of Oil and Other Hazardous Substances
      • Discharge of Oil Placard
      • Waste Management Plan
    • Topic 16: Protect the Environment
      • Aquatic Nuisance Species
      • Stop the Spread of Nuisance Species
      • Video: Aquatic Invasive Species
    • Topic 17: Boating Accidents and Casualties
      • What You Must Do if Involved in an Accident
      • Reporting an Accident
    • Topic 18: Enforcement and Penalties
      • Who Enforces Boating Laws?
    • Topic 19: Summary
      • What You've Learned
      • Video: Unit 4 Review
  • Unit 5: Boating Emergencies
    • Topic 1: Risk Management
      • Prepare for and Prevent Accidents
      • Practice Risk Management
      • Typical Boating Fatalities
      • Increased Risk Due to Boating Stressors
      • Increased Risk Due to Dehydration
      • Minimize Risk by Avoiding Alcohol
      • Understand Alcohol Impairment
      • Video: Avoid Alcohol
      • Minimize Risk by Wearing PFDs
      • Keep PFDs Readily Accessible
      • Have PFDs of the Proper Size
      • Maintain PFDs in Good Condition
      • Consider Inflatable PFDs
    • Topic 2: Rescue Techniques
      • Reach, Throw, Row, or Go
      • Animation: Reach, Throw, Row, or Go
    • Topic 3: Capsizing, Swamping, or Falling Overboard
      • Ending Up in the Water Unexpectedly
      • Preventing Capsizing, Swamping, or Falling Overboard
      • If You Capsize, Swamp, or Fall Overboard
      • If Your Boat Sinks or Floats Away
      • If a Passenger Falls Overboard
      • Preventing Falls Overboard From Small Boats
    • Topic 4: Avoiding Collisions
      • Preventing a Collision
      • Video: Avoiding Accidents
    • Topic 5: Dealing With Fire Emergencies
      • Preventing a Fire
      • If a Fire Erupts on Your Boat
      • How to Use a Fire Extinguisher
    • Topic 6: Running Aground
      • Preventing Running Aground
      • If Your Boat Runs Aground
    • Topic 7: Cold Water Immersion and Hypothermia
      • Cold Water Immersion Kills
      • Stages 1 and 2 of Cold Water Immersion
      • Stages 3 and 4 of Cold Water Immersion
      • Preparing for Possible Cold Water Immersion
      • Surviving Cold Water Immersion
      • Protecting Against Rapid Heat Loss
      • The HELP and Huddle Positions
      • Treating a Victim of Cold Water Immersion
      • Video: Preparing for Emergencies
    • Topic 8: Carbon Monoxide (CO) Poisoning
      • What Is Carbon Monoxide Poisoning?
      • Preventing CO Poisoning Before You Go Boating
      • Preventing CO Poisoning While Boating
      • CO Poisoning: Boat Exhaust
      • CO Poisoning: Teak Surfing
      • CO Poisoning: Other Situations
    • Topic 9: Personal Injuries
      • How to Respond to Injuries
      • A First-Aid Kit
    • Topic 10: Weather Emergencies
      • Changes in the Weather
      • How to Avoid Severe Weather
      • Severe Weather: Prepare Your Boat and Passengers
      • Severe Weather: Go to Shore or Ride it Out?
      • Weather Warning Display Signals
    • Topic 11: Summoning Help
      • What You Need on Board to Summon Help
      • Using a VHF Marine Radio
      • Issuing a MAYDAY Call
      • VHF Marine Radio Channels
    • Topic 12: Summary
      • What You've Learned
      • Video: Unit 5 Review
  • Unit 6: Enjoying Water Sports
    • Topic 1: Responsibilities of a Boat Operator
      • Sharing the Fun of Your Boat
      • Responsibility to Your Passengers
      • Pre-Departure Checklist
      • Video: Preparing to Ride
      • Responsibility to Others Operating Your Boat
      • Responsibility to Others Operating Your PWC
      • Responsibility to Environment: Keep Waterways Clean
      • Responsibility to Environment: Practice the Three Rs
      • Responsibility to Environment: Protect and Preserve
      • Responsibility to Environment: Avoid Toxic Products
      • Common Ways Boaters Harm the Environment
      • Responsibility to Others Using the Waterways
    • Topic 2: Small Boats and Paddlecraft (Canoes, Kayaks, and Rafts)
      • Paddlers Are at Risk
      • Preparing for Paddling
      • Safety While Paddling
      • River Hazards
      • If You Capsize While Paddling
    • Topic 3: Water-Skiing and Tubing
      • Before Towing a Skier
      • When Starting to Tow a Skier
      • While Towing a Skier
      • What a Skier Should Do
      • Hand Signals for Skiers
      • Animation: The "Pendulum Effect"
    • Topic 4: Scuba Diving and Snorkeling
      • Boaters and Divers Need to Be Cautious
    • Topic 5: Windsurfing and Sailing
      • Safety While Windsurfing
      • Safety While Sailing
      • Sailing Safety Tips
    • Topic 6: Fishing and Hunting
      • Anglers Who Use Boats to Fish
      • Boating in the Vicinity of Anglers
      • Hunters Who Use Boats to Hunt
      • Safety Tips for Anglers and Hunters
    • Topic 7: Summary
      • What You've Learned
      • Video: Unit 6 Review
View Course Outline

Boat and PWC operators may encounter physical structures such as dams, locks, and bridges. You need to be extra cautious in these situations.

  • Dams pose dangers both above and below the dams.
  • The low-head dam is the most dangerous type of dam and has been named the “drowning machine.” They may not be easily spotted because the top of a low-head dam can be several feet below the water’s surface. Because of their small size and drop, low-head dams do not appear to be dangerous. However, water going over a low-head dam creates a strong recirculating current or backroller (sometimes referred to as the “boil”) at the base of the dam. Even on small rivers, the force of the backroller can trap your boat against the face of the dam and pull you under the water—even while wearing your personal flotation device (PFD). Be aware that on large rivers or during high water, the backroller or boil may be located more than 100 feet downstream of the dam. Avoid low-head dams.
Low-head dam

Low-head dams pose a serious danger to vessel operators. Surface currents below low-head dams can suck vessels toward the face of the dam. Currents above low-head dams can sweep vessels over the dam. The recirculating currents and turbulent waters below these dams can swamp vessels and drown boaters.

  • Unit 3 of 6
  • Topic 3 of 9
  • Page 1 of 8
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Tag » What Is A Low Head Dam