Lucite replica of a tunnel boring machine, 2-1/2 inch diameter x 4 inches high. Working with the International Boundary and Water Commission (IBWC) and the City of San Diego, Parsons Corporation designed the SBOO to meet California discharge requirements to eliminate pollutants from water, beaches and preserves. The SBOO extends 3.5 miles offshore and discharges effluent in 100 feet of water. This was donated by F. D. Schlesinger, Director, Metropolitan Wastewater. (See groundbreaking shovel artifact)