I did an upstream then downstream round trip on the South Branch of the Raritan River from the merger point with the North Branch up to Neshanic Station which is about 5 ½ miles one way. The weather was perfect but the water level was low. Even so, this was a very enjoyable day of kayaking.
Downstream: USGS 01398102 South Branch Raritan River at South Branch NJ – just over 2.1 feet
Upstream: USGS 01397420 SB Raritan R at Black Point Rd at Neshanic Sta NJ – 4.65 feet
I was able to get through everywhere without having to get out of my 13’ kayak with some hand pushing over a half dozen class I shallow spots. There was only one brief class II rapid just upstream from the Studdiford Drive bridge but I was able to paddle up through it with pushing off a rock.
I put in at the Old York Road bridge over the North Branch, then went right to the North-South Branch merger point and then turned right again to go upstream on the South Branch. I stopped upstream at the historic Central Jersey Railroad bridge and Ammerman Mill just below the rapids there.
I probably would not try to go so far upstream if the level was lower as I don’t like to get in and out of the boat to walk over the shallow spots. But, the deep section down near the North-South merger would still be a pleasant area to paddle around. If you go down the main Raritan River there be aware of a dam about .4 mile downstream.