What it is
River feeder is not commercial method fishing with a different view. The water moves, so the feeder has to hold, the bait has to belong in that movement, and the close season on rivers, streams and drains in England and Wales — 15 March to 15 June inclusive — is not optional.
You find the crease or the hole, pick a feeder that holds without bouncing into the snags, and build a bed or a trickle depending on the fish. Maggot feeder for a crease full of roach and barbel. Cage of groundbait for bream on a slower stretch. A straight lead when the feeder snags every chuck.
16 June is opening day. This app will not tell you to fish a river in May.