An ancient estate of St. Pancrazio monks, the name of the Nature Reserve derives from the fresh waters of Magliana ditch, where Totila, the King of Goths, stopped in the year 547, when he conquered Rome. From an environmental point of view, the area is part of the Ponte Galeria - Arrone ecosystem in the north-western section of the town. Acquafredda Valley is bordered by a number of smaller valleys formed by sand and clay, but also tuff deposits. The soil is fertile and characterized by a great variety of plants: Cork oak, Elm, Equisetum, Dog rose, Juniper, Thistle, and Orchids may all be found here. Some of these plants survive solely near the local waterworks system. The riparian environment along the banks of the ditch plays an important ecological role: in the willow and canebrakes formations there are several birds which usually live in wetlands, like the Coot, the Moorhen, the Cetti's Warbler, and the Penduline Tit. There are also some fine farming estates, as well as a medieval tower.