A feature of the Kalk Bay caves is a phenomenon known as 'case-hardening'. This appears as a thin crust of hard rock, on top of the much sandier, softer base rock. Once this crust has been removed, the base rock erodes very quickly. This has taken place in a number of high traffic areas in the Ronan's Well. Litter Some of the more popular caves, like Picnic Cave and Muizenberg Cave, have a serious litter problem.
People often camp in the caves, and leave large amounts of rubbish lying around.
Another, possibly more dangerous type of litter comes in the form of batteries. Cavers use batteries to power their torches, so a large number of batteries are taken into the caves. Whether by accident or design, these batteries are often left in the caves. The battery casings deteriorate rapidly in the humid cave atmosphere, and release chemicals into the cave water supply. The effects of these chemicals on the cave environment are unknown.