"The beginning" of Sawmill brook - VFW parkway and West Roxbury parkway (2007) The blue sign tells you the outflow pipe numbers.
Arnold Arboretum - Hemlock Hill at South street (2007)
I've covered three tributaries of Stony Brook: the main source in Hyde Park, the east branch draining the Canterbury cemetery area, and the buried Roslindale south branch. Next is the Bussey Brook - formerly the Sawmill. The old maps show it starting near the Brookline, near today's West Roxbury Parkway. Luckily, the Arnold Arboretum and the Allandale Woods have protected most of the course of the Bussey, so much of it is now above ground. I grew up in Jamaica Plain, so I knew the Bussey from trips to the Arboretum, where it enters near the Hebrew Rehab hospital and runs past Hemlock Hill before passing under South Street and of towards Forest Hills. I actually have a memory of crawling through the culvert under South Street during the mid-Sixties, for what seemed like an exotic adventure at the time. The water just seemed to appear at one end of the Arboretum and vanish at the other, which didn't bother me at the time. Now, I like to dig a little deeper, so I've looked into both the beginning and the end of the Bussey.
When you drive Center Street past the start of the V.F.W. Parkway, the Bussey shows itself on the Hebrew Rehab. side, but disappears under the road. In this case, a little exploration reveals that the brook flows through the Allandale Woods along the parkway for much of the way towards the West Roxbury Pky. On my first trip to explore the Allandale Woods I found the brook, but I didn't get all the way back to the source. Today I started from the West Roxbury Pky. and found the start of the brook. Coming north on the West Roxbury Pky.from Holy Name church, just before you turn right on to the V.F.W. Pky. the culvert shown in the picture on the right empties into the woods. So the Bussey Brook begins as a storm drain outflow. A short way up the V.F.W., it crosses under the road and runs within sight of the sidewalk and continues northeast until it goes underground and passes under Centre Street at the Hebrew Rehab. hospital.
Around the back of the hospital, it passes under Walter St. and enters the Arboretum at a gate. It continues towards Forest Hills, past Hemlock Hill, and under South St. (see picture). The land on the east side of South St. is now open, with a gate and a path to Forest Hills. This is mostly low wetlands, between South St. and the train line. Towards the northeast corner, there is a grated culvert that (I assume) sends the water under the Forest Hills Station area and joins with Stony Brook proper.