Waterfront, Maltkiln Road, Barton-upon-Humber, DN18 5JR.
A Mumbler favourite, just over the Humber bridge is this nature reserve (the blue roofed buildings you can see as from the bridge). Excellent paths and boardwalks around several lakes with ducks to feed and birds to spot. Paths then go through woods and up onto the river front for great views back to Hull and the bridge. Two good parks are located in the main car park.
Free to walk around. Also a good visitor centre and cafe to stop at.