The Alnwick Garden's Grand Cascade, designed by Jacques Wirtz, is a three-tiered water feature built from local sandstone. Constructed in 2001, it's a central element of the garden and runs along the north-south axis. Hornbeam hedges frame the Cascade, while a water display with 120 jets culminates in a volcanic eruption effect. An extensive pump and treatment system ensures water sustainability for the Cascade and surrounding features.