Groundwater sapping

Groundwater sapping is when water flowing underground weakens and erodes away soil and rock, causing parts of the land above to collapse or sink. It's like when you pour water on sandcastle and it falls apart.

Groundwater is water that lies beneath the surface of the earth. When it rains, some of the rainwater seeps down into the ground and fills up underground spaces called aquifers. These aquifers are like sponges that hold onto the water.

When the water in the aquifers builds up, it can start to flow through the rock and soil. This water flowing underground can pick up and carry away particles of soil and rock, just like a river carries away dirt and rocks.

Over time, the water flowing underground can erode away enough soil and rock to create a void or underground chamber. If this void or chamber is close to the surface of the land, the ground above may start to sink or collapse. This can create sinkholes, which are large holes in the ground that can be dangerous and damaging to buildings and roads.

So, groundwater sapping is when water flowing underground causes areas of land to weaken and collapse, just like pouring water on a sandcastle causes it to fall apart.