There are lakes Boadella ,Susqueda, Sau. All 3 lakes are located in the province of Girona, Boadella 14 km from the French border, Susqueda and Sau at the foot of the Guillerias mountain range. Fish: Boadella: pike, zander, perch, American perch, common carp, catfish, Suskeda - Sau: common carp, catfish, American perch. I lived in property in Girona and rented a car to get to the lake Boadella.
The Ter (the river that flows through Girona) is running over its banks at the moment and flooding even the town of Angles. Almost all rivers are in flood at the moment after heavy rains in January. I am sure though that it will be fine by September and re stocking will mean that there will be a good head of trout in at least the Angles beat.
Have you thought of heading up into the Pyrenees in Lerida? September is a great time for the Noguera Pallaresa, or the bottom stretches of the Segre river. If you want any more info dont hesitate to let me know,