Can you access the lake from trails? I saw in some photos there was a path to it but I can't tell if its a cliff or if there is a shore.

No access to the lake from the trails

The Nature Trails you walk on at Garvan Gardens go right by the lake.

Katie, outside the entrance to the formal gardens there is a road/path to the boat docks. There is a picnic table there, also. I frequently tie up at the bost docks and then go to the gardens for a morning walk.