A $30 million gift from Mary and Jon Shirley established them as foundational donors. As part of constructing the sculpture park, $5.7 million were spent transforming of the seawall and underwater shoreline inside Myrtle Edwards park. A three level underwater slope was built with 50,000 tonnes of riprap. The first level of the slope is large rocks to break up waves. The second is a flat "bench" level to recreate an intertidal zone. The lower level is covered with smaller rocks designed to attract sealife and large kelp. The aim for the recreated strand was to help revitalise juvenile salmon from the Duwamish River and serve as a test site for future efforts.
