Here are some key distances measured from the ARC Dock.

Landmark Distance
GA-400 Bridge 3000 m
St. Andrews Dock 2000 m
Roswell Rd. Bridge 1000 m
AJRA Dock 500 m
Azalea Park Pavilion 500 m
Foot Bridge 1400 m
A-Frame 2000 m
Fishing Pier 2400 m
Cliffs 4000 m
Mid-Basin 4700 m
Morgan Falls Park 5500 m
Morgan Falls Dam 6500 m

Here is a list of other commonly used landmarks and the distances between them for your convenience:

Downstream Upstream Distance
Roswell Rd Bridge. GA-400 Bridge. 1800 m
Azalea Park Pavilion Roswell Rd. Bridge 1500 m
Azalea Park Pavilion Huntcliff Dock 750 m
Utility Pole AJRA Dock 1000 m
316 mile marker Roswell Rd. Bridge 2000 m
Foot Bridge Azalea Park Pavilion 1000 m
Fishing Pier Foot Bridge 1000 m
Cliffs A-Frame 2000 m
Morgan Falls Park Cliffs 1600 m
Dam Fishing Pier 4000 m