[4] The park is named for a manmade 22-foot (6.7 m) tall waterfall over which is pumped 5,000 US gallons (19,000 L) of water per minute.[4] It is described as "one of the most expensive parks per square foot ever built in the United States".[5] Roger Sale says in the guidebook Seeing Seattle that the park is locked at night to keep out the sizeable Pioneer Square homeless population.[6] The park's Japanese garden includes Chamaecyparis obtusa and other botanicals native to Japan, and a pool designed by Yoshikuni Araki.[7][8] The garden won the Environmental Award of the American Nurserymens Association in 1981.