A fascinating article about this destroyed and landfilled area :
'An expatriate revisits his Yokohama childhood haunts' (Japan Times - May 19, 1999)
John Carroll, 'Trail of Two Cities', ed. Kodansha, Tokyo, 1994, p. 120:
"There used to be great scenery and swimming all along this coast from Honmoku to Kanazawa Hakkei. They have been replaced by one of the nation’s largest petrochemical and industrial districts, the 610-hectare Negishi Bay Seaside Industrial Zone. The reclamation work was started in 1959 and completed in 1964. Among the companies with plants here are Nippon Petroleum, Tokyo Electric, Tokyo Gas, and Nisshin Oil Mills.
Either out desire to compensate the local people for what they had lost or out of diabolical sense of humor, the metropolitan government built in place of the beaches a giant pool complex that can accommodate twenty-five thousand people a day..."