A gabion is a mesh cage filled with stones that is used to restrict the flow of water. They work because the stones within the cage form a barrier, which allows some water to pass through the gaps between them while keeping out the bulk of the water. Usually, you will stack several gabions on top of each other to form a wall. They can be effective in the right place and are relatively inexpensive to install.
Gabions are unsightly, especially after they have been in the water for a long time and the cages have started to rust.
Gabions take up a lot of space on a beach, because to be effective you may need to be more than one. This can make the beach a less desirable place to bathe and could also make it look more crowded.
Not Easily Replaceable
If the cage becomes too rusted or the rocks too worn, you must remove the entire gabion. If the cage that needs replacing is the one at the bottom of a pile, you have to remove all of them, which can make repairs a lengthy and expensive process.
Equipment Difficult to Source
The grade of rock that is needed to fill a gabion is 3 to 5 inches, which may be hard to find. The cages are not readily available. In addition, because of the size and weight of most gabion cages, you need heavy lifting gear to move them into place.
Both the cage and its contents will deteriorate over time, which means that you will need to replace them, leading to more expense and greater difficulty locating the resources.
The effectiveness of the gabion is limited to areas of small drainage areas and intermittent water flow, according to the Environmental Building Design and Construction Portal.