Can people or animals walk on the liner?

Both the regular strength and extra strength liners are strong enough to handle some traffic as long as there’s nothing sharp. That being said, it’s always a good idea to protect the liner if you can, especially if it may come in contact with claws, foot traffic, or digging animals. A common way to protect a liner is to place a layer of pond liner underlay over top of it, followed by gravel, rock, brick, or another material to prevent direct contact with the liner. If you plan to have animals walk on the liner, try to keep the slope very gentle or use steps. A steep slope can cause slipping or thrashing, which could damage the liner.