Plunge pool Plunge pool A plunge pool (or plunge basin or waterfall lake) is a deep depression in a stream bed at the base of a waterfall or shut-in. It is created by the erosional forces of cascading water on the rocks at formation's base where the water impacts. The term may refer to the water occupying the depression, or the depression itself. Plunge pools are formed by the natural force of falling water, such as at a waterfall or cascade; they also result from man-made structures such as some spillway designs. Plunge pools are often very deep, generally related to the
Coastline Plunge that takes them through a short enclosed tunnel. Once the tube exits the tunnel, it is taken up the side of the funnel part, going back and forth along the sides until it comes out the end through a water curtain into a splash pool, which it shares with Surge. Riders of this slide are also required to be no shorter than 48 inches. This is the only slide in the complex that is denoted as an "Aggressive Thrill Ride". Hyrdo is one of two slides added to Coastline Plunge in 2013. It is an orange slide in which riders