Digging separate entrance

Yes you would need a permit such as building permit site plan or grading permit and maybe call the city or Someone to locate electrical or plumbing lines if needed.

You most apply for permit when going to have a side entrance walk up, 1) Survey ( Get it from city) 2) Existing floor Plan 3) Stamped walk up basement drawing 4) pay the permit fee 5) Find a proper contractor 6) contractor most pass all the city inspection 7) sign off letter

If the purpose of the separate entrance is needed to serve a secondary unit, (basement apartment) you will need to show that with a full floor plan, sections, details along with the upper floors (for reference), elevations and a site plan. You will need building permit, drain for the floor drain and sump pump, and plumbing for the secondary unit. You will need also HVAC. So to answer your question you will need 4 permits. If the scope of work is only for the separate entrance into a basement then 2 permits. BLD & DRN. I hope this helps:)