If you’re planning your first caving journey, you might wonder if you’ll come across water or not.
Not all caves have water in them, but most do. The primary cause of cave formation is from water flowing through soluble rock. So even caves that don’t have flowing water usually still have stagnant water inside. But some caves don’t have any flowing water in them, we call these relict caves.
The presence of water in caves is part of the reason some of them are so beautiful, but is the water safe? Can a cave flood? Let’s look at these questions and more.
Caves that have water flowing through them are called “active” caves. Active caves can be further categorized by how the water flows through them. Caves that have water flowing into them are called inflow caves, while the water flowing out makes them an outflow cave. “Through caves” are those where water has created a tunnel all the way through one end and out another. Some people just refer to them as “wet caves” as well.
Caves can flood during rainfall. There are natural pathways for water to run into a cave easily. As the rain hits the ground, it will find the path of least resistance into the ground. Cave openings on the ground’s surface are usually slightly lower than the ground in the surrounding area, which causes all the rainfall in a certain radius to be channeled into the cave.
You’ll need to do your research on the cave you plan to explore and become familiar with its probability of flooding. You also need to check the weather forecast to determine how much rain there will be on the day that you wish to explore the cave.
Besides keeping an eye out for rain on the day, you also need to find out how much rain has been falling in the last few days or weeks to know if the water levels inside the cave are low enough to explore safely.
If you’re going caving in a snowy area, watch out for melting snow. The sun can melt a layer of snow quickly and create rivers leading into the cave. Caves can easily flood from melting snow. In areas that are icey, the same concept applies, the ice can melt and cause caves to flood.
Caves can be dry. Most dry caves are higher than the surrounding terrain. Caves that have formed in mountains are good examples of dry caves. Although, a cave inside a mountain does not guarantee that it’s completely dry. Rainfall almost always introduces plenty of water into a cave, even if it’s high in the mountains.
In some areas, there are dry caves in lower parts of the ground, but most of the time there will be a certain amount of water once you go deep enough into the cave because you’ll reach the water table in the earth. Water tables vary in depth, but most of them are around 50 to 300 feet below the earth’s surface.
Most caves hold freshwater inside them. Freshwater merely means that the water is not directly from the sea and that it contains less than 1000 milligrams of dissolved solids per liter.
So that means that only sea caves, also known as littoral caves, are the only caves that aren’t considered being freshwater caves because of the amount of salt in the water.
Because we find most caves inland, most of the water inside them is not from the sea, this makes them freshwater caves.
You should never drink cave water unless you’re in an emergency and fear you might dehydrate. If you feel you have to drink some water to keep hydrated, you could find some dripping from the ceiling from stalactites. Flowing water is almost always a better option than water that’s not moving.
The same safety rules apply to water in caves and water above ground, namely:
- Flowing water is more likely to be safe to consume than stagnant water.
- Water that has a strong odor might be contaminated and unsafe to drink.
- The clearer the water, the more likely it’s safe to drink.
- If the water is bitter, it may be unsafe for consumption.
- If the water smells like rotten eggs, it may contain hydrogen sulfide which is unsafe to consume.
Cave water is normally so clear because there isn’t anything to lift settled sediment. There’s no wind to blow all sorts of debris into the water. Cave water is also filtered through the ground, which cleans it before creating pools inside.
Cave water is clear because it’s pushed up from aquifers below. Water from aquifers is naturally crystal clear as the earth filtrates it constantly.
Why Are Some Caves Dry?
Caves can be dry if the environment has changed since the cave was formed. Some caves are formed purely by rainfall and can soak up all the water they receive. Caves can also be dry when they’re formed by earthquakes and other natural disasters.
However, because caves don’t receive direct sunlight, there’s a high likelihood of some moisture, humidity, and pools of water being present as they don’t have an opportunity to evaporate as easily as water above the ground’s surface.
Not all caves have water in them, but most do. Even if it’s just water that’s gathered up from rainfall or melting snow. Most caves have freshwater inside them unless they’re situated next to the sea. Water has a hard time evaporating inside a cave and the main causes of caves losing their water is from seepage further into the ground or from pathways that lead out of the cave.