| Nov. 1961 |
Water Resources Development Promotion Law promulgated and implemented
Water Resources Development Public Corporation (WARDEC) Law promulgated
(implemented in Feb. 1962) |
| Apr. 1962 |
Tone and Yodo River Systems designated for water resources development based on the Water Resources Development Promotion Law |
| May. |
WARDEC established |
| Aug. |
Tone River System Water Resources Development Basic Plan developed
Yodo River System Water Resources Development Basic Plan developed |
| Oct. |
Comprehensive National Development Plan approved by the Cabinet |
| Oct. 1964 |
Chikugo River System designated for water resources development based on the Water Resources development Promotion Law |
| June 1965 |
Kiso River System designated for water resources development based on the Water Resources Development Promotion Law |
| Feb. 1966 |
Chikugo River System Water Resources Development Basic Plan developed |
| Nov. |
Yoshino River System designated for water resources development based on the Water Resources Development Promotion Law |
| Mar. 1967 |
Yoshino River System Water Resources Development Basic Plan developed |
| Oct. 1968 |
Aichi Canal Public Corporation incorporated into WARDEC
Kiso River System Water Resources Development Basic Plan developed |
| May 1969 |
New Comprehensive National Development Plan approved by the Cabinet |
| Dec. 1974 |
Ara River System designated for water resources development based on the Water Resources development Promotion Law |
| Apr. 1976 |
Tone and Ara River System Water Resources Development Basic Plan developed |
| Nov. 1977 |
Third Comprehensive National Development Plan approved by the Cabinet |
| June 1987 |
Fourth Comprehensive National Development Plan approved by the Cabinet |
| Oct. |
National land Agency developed National Comprehensive Water Resources Plan (Water Plan 2000). |
| Feb. 1990 |
Toyo River system designated for water resources development based on the Water Resources development Promotion Law |
| May |
Toyo River System Water Resources Development Basic Plan developed |
| Mar. 1998 |
Grand Design for National Development in the 21st Century (Fifth Comprehensive National Development Plan) approved by the Cabinet |
| June 1999 |
National land Agency developed National Comprehensive eater Resources Plan (Water Plan 21). |
| Dec. 2001 |
Public corporations consolidation plan approved by the Cabinet |
| Dec. 2002 |
Japan Water Agency Law promulgated and implemented |
| Oct. 2003 |
Japan Water Agency established |