Before restoration, the canal (with waters from Slad Brook, Painswick Stream & Ruscumbe Brook) was diverted directly into the River Frome at this point. This also marked the start of the canal infilling from here to near Ryeford Double Lock.
(Tap / click images to enlarge)
The line of the canal was to the left, and the outflow into the river is just visible to the right. As can be seen from the post restoration photos, the footbridge is still in situ.
This is an original weir that helped maintain the correct water level in this section of canal by discharging surplus water into the adjacent River Frome. The structure was left in place when the canal was infilled but is now redundant. The new confluence weir (above) now fulfils this function.