The San Diego-La Jolla Underwater Park spans 6,000 acres (24 km2) of ocean bottom and tidelands. The park has become a popular destination for snorkelers and scuba divers. The park was created by the City of San Diego in 1970 and actually has two other parks within it: the Ecological Reserve and the Marine Life Refuge.
Within the underwater park are two artificial reefs, created to attract and enhance marine life. The first was built in 1964 with Santa Catalina quarry rock dumped in 70 feet (21 m) of water near Scripps Canyon. The second was started in 1975 and is located at a depth of 40 feet (12 m) just offshore from Black's Beach.
From La Jolla Shores, the ocean bottom slopes gently out to sea. The reefs keep the waves minimal, making this an entry point for divers and kayakers. Kelp beds on the outer edges of the slope are popular fishing spots and great for observing seals, dolphins, birds and fish.
Beyond the slope the bottom takes a sudden and 500-foot (150 m)-deep plunge into the La Jolla Canyon. The canyon reaches depths of 600 feet (180 m) within the park. The abrupt drop and abundance of marine life help to explain why migrating whales can often be spotted close to shore.
A 30-foot (9.1 m) by 75-foot (23 m) lithocrete map of the underwater park was completed in September 2008 at La Jolla Shores beach. It is located near the boardwalk between the restrooms and the children's play area at the south end of Kellogg Park.
The Ecological Reserve was established in 1971 and has since been expanded to a total of 533 acres (2.2 km2). It covers all of La Jolla Cove to a point midway on the La Jolla Shores beach. No fishing or scavenging is permitted within the reserve.
The Marine Life Refuge encompasses the Scripps Pier at Scripps Institution of Oceanography and was established back in 1929 as an academic research area. Recreation and fishing are permitted in the refuge.