Hole-In-The-Wall is named after the resurgence spring which emerges from a limestone rock wall. This type of feature occurs when water travels underground through a complex series of caves and either works its way down to a level of impermeable rock or until it reaches the top of the water table. The water flow may then travel along the surface of the impermeable rock until it reaches the surface as a spring. This type of feature is usually associated with cave features, particularly where the predominant stone is limestone. Visitors to Hole In The Wall Provincial Park will be amazed by the size and sheer volume of water. Surrounded by lush vegetation and a spectacular vertical blue-gray wall of limestone, this geological feature is impressive and easily accessible via a short 40 m walk from the road.

(from BC Parks Hole In The Wall Website Page )