RedactedNarrative: 22 year old man was rescued from the Walhonding River after being in the river for an extended period of time.  The 22 year old was transported for treatment.Occupants 1 & 2 were each paddling down the river with an oar. They both admitted freely they had been drinking liquor and smoking marijuana. Occupant 2 left the boat to swim and had been swimming for quite a while. They became separated out of site just before reaching the CR 20 and SR 715 area. Occupant 1 became grounded on a sandbar near shore 20-30 yards upstream of the old railroad bridge. The boat flooded and sank. Occupant 1 climbed up the bank and began looking for occupant 2. Motorists happened by and called 91 I for assistance. A search ensued for occupant 2. Occupant 2 was later observed approximately .75 miles downstream having been washed through the gates and over the spillway of Mohawk Dam. He was rescued by a good Samaritan and fire dept personnel near the Army Corps campground. He was conscious and breathing, transported to the hospital. The vessel and all personal property was lost. The vessel was not registered nor was the HIN number available or recorded. Occupants advised they had two pfd's available, but none were used. The river level was above normal pool with some current but not what would be considered dangerous for conditions in the area.