It does not appear that you are eligible to apply for an encroachment agreement.
Private enclosures of road right of way (i.e., boulevard) are not supported as this land is required to provide free and clear access to The City and utility providers for maintenance of public infrastructure, utilities, public trees, and for public access.
If you have site-specific challenges associated with building your fence or similar structure on your property line that you would like to discuss further, please email LandAdmin@calgary.ca and a team member will respond to you within 2 weeks.