If the river is safe for nonpregnant people, it's safe for pregnant people.
Is this a river that's monitored by Parks and Rec or LCRA for bacteria levels?
You can swim in rivers and pools. If you lose your mucus plug I would keep it to pools. The mucus plug should protect your baby from anything in the river. Swimming feels so good, takes the pressure off your joints!
Its definitely safe to go swimming especially when your hot doctors recommend taking showers but swimming is way better but in a river ? Definitely not rivers is full of bacteria and something may scratch your belly and you can be in pain, fresh clean water is the way to go!
Of course it's safe. Once your water breaks obviously it would be a bad idea. But as long as it's fresh running water, not brackish or gross, go for it. I can't wait until the river beach in my town is open for the season so I can go every day until I deliver! I'd much rather be in fresh water than in a pool filled with nasty chemicals.
Swimming is definitely great during pregnancy but in a river i way no your open to catching something