Rowing down the Aa river is a 25-km tour from Houlle to Gravelines. You will depart from the Houlle river within the Audomarois marsh. The Bistade drawbridge is lifted to the sound of horns when boats are passing, attracting many an onlooker. The rowers will be able to admire the fauna (mallard ducks, herons, swans …) and flora all along the journey down the small river. The tour will end by a friendly drink and a meal taken within the Gravelines Aviron club, the premises of which are located on the edge of the Olympic rowing arena.