Alluvial Wall is an outdoor 2001 sculpture by Peter Nylen and the architectural firm Rigga located along the Eastbank Esplanade in Portland, Oregon.

The sculpture is made of mild steel, cast silicon bronze, cast iron and electric light, and measures 1 foot (0.30 m), 6 inches (15 cm) x 3 feet (0.91 m) x 13 feet (4.0 m), 6 inches (15 cm).

"[1] In her walking tour of Portland, one author said the sculpture resembles "what you might see on a beach after the tide goes out".

Its copper "kelp-like strips" are embedded with black metal objects, including a child's ball, a morel mushroom and a railroad spike.

[2] The sculpture is one of four by Rigga along the esplanade; the others are Echo Gate and Stack Stalk by Ean Eldred and Ghost Ship by James Harrison.