Quarries, Ponds and Reservoirs: Why 'No Swimming' Signs Matter

Quarries, ponds and reservoirs look calm, but many are deep, cold and very hard to climb out of, with no lifeguard and no easy way for rescuers to reach you. If a sign says No Swimming, take it seriously and find a designated swimming area instead.

These places draw swimmers for the same reasons: clear or still water, a cliff to jump from, no crowds. Those same features are what make them dangerous. This guide explains why, and what to do instead.

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Why these places are riskier than they look

A quarry is a pit dug for stone or gravel. When the digging stops, it can fill with water. The federal Mine Safety and Health Administration (MSHA) runs a campaign called Stay Out–Stay Alive to keep people out of these sites. It warns:

Water-filled quarries and pits hide rock ledges, machinery, electrical currents, and other hazards. The water may look refreshing but can be deceptively deep and dangerously cold. Steep, slippery walls can make exiting the water difficult. (opens in a new tab)

MSHA adds that each year, explorers, hikers and off-roaders are injured or killed while exploring, swimming or playing on mine property (opens in a new tab).

Ponds and reservoirs share many of the same problems:

• No lifeguard. CDC advises choosing swimming sites that have lifeguards when possible (opens in a new tab). Most quarries and ponds have none.
• Hard to see the bottom. CDC notes that natural water has hidden hazards such as rocks or vegetation, and limited visibility (opens in a new tab).
• Hard to get out. Steep rock walls and muddy banks leave few places to climb out when you're tired or cold.
• Hard to reach. Rescuers may need time to get equipment to a remote pit or the far side of a pond.

Cold water and sudden depth

Warm air doesn't mean warm water, and a deep quarry or pond can feel much colder than it looks. The National Weather Service says cold shock can be just as severe in 50-60°F water as in 35°F water (opens in a new tab), and that gasping can be triggered by water as warm as 77°F (opens in a new tab). The U.S. Army Corps of Engineers warns that if you fall or jump into water colder than 70 degrees, you can inhale water from involuntary gasping (opens in a new tab).

That gasp is why strong swimmers drown in places like this. The National Center for Cold Water Safety says that while breathing hard from cold shock, swimming as short a distance as 6-10 feet is often impossible, even for good swimmers (opens in a new tab). Learn more in cold water shock and the 1-10-1 rule.

Depth changes suddenly, too. The edge of a quarry or pond can drop off with no warning. The American Red Cross warns about drop-offs that can unexpectedly change water depth (opens in a new tab).

Cliffs, ledges and hidden objects

Quarry walls invite jumping. But you can't see what is under the surface, and the MSHA warning above lists rock ledges and machinery (opens in a new tab) among the hidden hazards.

The Red Cross is direct:

• Do not enter the water from a height, such as a bridge or boat. (opens in a new tab)
• Always enter unknown or shallow water feet first. (opens in a new tab)
• Dive only in water clearly marked as safe for diving, at least 9 feet deep with no underwater obstacles. (opens in a new tab)

A jump also puts your head underwater at the moment the cold hits. The National Center for Cold Water Safety warns that a cold-shock gasp with your head underwater means breathing in water (opens in a new tab). For more, see jumping and diving safety.

Retention and stormwater ponds near homes

Many neighborhoods, parks and parking lots have ponds built to hold rainwater. They can look like nature, with grass and birds. They are working drainage systems, and they are dangerous for children and pets.

The Lake County, Indiana, Health Department lists the dangers:

• Steep, slippery slopes that can be very difficult to climb out of (opens in a new tab) after a fall.
• Water deep enough to pose a significant drowning risk, even for adults who aren't strong swimmers (opens in a new tab), with sudden drop-offs (opens in a new tab).
• Inflow and outflow pipes that can create strong, often hidden, currents (opens in a new tab) that pull someone underwater or trap them against a grate.
• Thin and unstable ice in winter (opens in a new tab), because the water level and flow keep changing.
• Pollutants from runoff (opens in a new tab), such as oil, fertilizer and animal waste.

Ponds near home are a special concern for families of children who wander. In a study of news-reported drownings of children with autism, ponds were the most common location (opens in a new tab), usually after the child wandered away. The study was small, but the lesson is clear. If your child tends to wander, read wandering and water: a safety plan.

What to teach children:

• Ponds are for looking at, from a distance. No wading, no fishing alone, no walking on the ice.
• If a ball or a pet goes in, leave it and get an adult.
• If someone falls in, shout for help and call 911. Don't go in.

Reservoirs and other managed water

Reservoirs and lakes behind dams are often run by a public agency, and the rules differ from place to place. Some have designated beaches with lifeguards. Others don't allow swimming at all. Look up the managing agency's rules before you go, follow posted signs, and stay well away from dams. See why low-head dams are so dangerous.

Life jackets matter here too. CDC says weaker swimmers of all ages can use life jackets in and around natural water (opens in a new tab), and children should wear them for all activities there.

Finding a legal, guarded place instead

The best way to handle a quarry or a No Swimming pond is to go somewhere better.

• Look for a beach or lake with a designated swimming area and lifeguard hours. See choosing a safe place to swim outdoors.
• In New York City, NYC Parks runs free public beaches with lifeguards on duty daily from 10 a.m. to 6 p.m. in season (opens in a new tab), and free outdoor pools (opens in a new tab) in every borough.
• If you or your teen want the thrill of deep water, a pool with a diving well and a lifeguard is a safer place to build those skills.

If someone is in trouble

Learn more in reach or throw, don't go.

What you can do today

• Talk with your teens about quarries and cliff jumping before summer starts. Ask where their friends go to swim.
• Walk your neighborhood and note any retention ponds. Show young children where they are and set the "look, don't touch" rule.
• Find the nearest beach or pool with lifeguards and save its hours.
• If your child wanders, add ponds near your home to your family safety plan.