Three campsites come to mind that I´ve visited near or have lake views, they are in Güejar Sierra, near Freila in Granada province and Puente Nuevo in Cordoba province.
Camping Las Lomas, Guëjar Sierra
A sloping site with fabulous views of the snow covered Sierra Nevada mountains and green lakes giving a Swiss feel.
Camping La Cabañuela, Friela
This is a flat site about 1.5km from the lovely Lake Negratin which has pedal boats, a bar and is great for swimming.
Camping Puente Nuevo, Puente Nuevo
A nicely-kept site with mature trees very near Embalse (reservoir) Puente Nuevo in Villaciosa de Cordoba.