In 1965, the Federal Water Quality Act, amongst many other things, mandated improving the Los Angeles sewage disposal system. Mayor Sam Yorty, and the President of the Board of Public Works, Louis Gill, involved Donald C. Tillman, Chief Deputy City Engineer, in improving the wastewater processing of the City. He was ordered to come up with a scheme.By 1970 a complete plan for TWRP-JG was in place. It would meet Federal Standards for sludge control, as ordered by Congress, but was so expensive it would require Federal subsidy. A court trial ensued; Los Angeles Vs. the Federal Environmental Protection Agency, and in 1975 a Consent Degree (compromise) was issued. Tillman’s plans for the TWRP were adopted with 75% Federal funds, 12.5% State funds and 12.5% City funds; $75,000,000 budgeted for wastewater processing. No funds were allocated for the JG.
Tillman, now City Engineer, continued to press for the garden, now with another Mayor, Tom Bradley. In 1979 Los Angeles agreed to finance the JG with S3,000,000. Kawana, who had designed it about 1970, had since actually built two gardens elsewhere. With his new experience he redesigned the JG and added the teahouse and Shoin building. Construction on TWRP-JG was started in 1980 and substantially finished by 1983.
The basic engineering concepts were to build an attractive “upstream” facility for removing 95% of the water from the sewage. At the very least this would relieve demand from the “downstream” main Hyperion facility at El Segundo and forestall the necessity of building another mainline sewage tunnel through the Valley. At the very most it would accomplish this and the 95% reclaimed water would be reused. The other 5% of the water would be used to carry the sludge down to Hyperion where it would be burned to generate electricity. The Valley facility would interface with the public through a Japanese Garden with a theme of the peaceful, beautiful uses of water.