http://lub.calgary.ca
Part 5: Low Density Residential
Division 1: General Rules
Retaining Walls
342 (1) A retaining wall must be less than 1.2 metres in height when measured from the lowest grade at any point adjacent to the retaining wall to the highest grade retained by the retaining wall.
(2) A minimum horizontal separation of 1.0 metre must be maintained between retaining walls on the same parcel.
Anything over 1.2m requires land use approval.
Building permit requirements:
https://www.calgary.ca/_layouts/coci...edirect=1&sf=1