 By 1958 , the WRU had concluded that a new national ground was needed due to flooding that often plagued Arms Park . After debate and disputes between the WRU and various other parties , including Cardiff RFC , in the 1960s , it was decided that a new national stadium would be built with a new ground for the Cardiff club backing onto it . The National Stadium , as it was known , was officially opened in 1970 . 
 By 1958 , the WRU <a href='been_done' title='1'><mark>had</mark></a> concluded that a new national ground was needed due to flooding <a href='null_relcl' title='2'><mark>that</mark></a>often plagued Arms Park . After debate and disputes between the WRU and various other parties , including Cardiff RFC , in the 1960s , it was decided that a new national stadium would be built with a new ground for the Cardiff club backing onto it . The National Stadium , as it was known , was officially opened in 1970 . 
By 1958 , the WRU done concluded that a new national ground was needed due to flooding often plagued Arms Park . After debate and disputes between da WRU and various other parties , including Cardiff RFC , in the 1960s , it was decided that a new national stadium would be built witt a new ground for the Cardiff club backing onto it . TdaNational Stadium , as it was known , was officially opened in 1970 .