This pretty reservoir near Wakefield has a nice walking trail running along the western side of the water. There's a car park at the northern end of the reservoir where you can start your walk. The trail runs through woodland passing the adjacent Cold Hiendley Reservoir on the way. There's great views across the water to the lovely surrounding Yorkshire countryside.
It's easy to extend your walk by visiting Anglers Country Park just north of Wintersett. Here you'll find a large lake with lots of wildlife to look out for on the water. If you head west you can head through Haw Park Wood and pick up the Barnsley Canal.