From the watershed, a series of nearly parallel ridges thrusts outwards towards the plain, progressively decreasing in height, sharply separated from the transverse river valleys. Beyond the extreme outlying hills lie the undulations of the stony upper plain, formed by the fusion of fluvial detritus, beyond which extends the wide fertile alluvial plain. Of the great swamps, which at one time characterized the lower Emilia and Romagna plain before systematic regulation of the waterways, remain only the Valleys of Comacchio and the stretches of water belonging to the Po Delta. Except for this river, which flows along the northern boundary of the region, all the water courses are of a torrential nature. In autumn and spring they are in spate while the water level is at a minimum in summer.
Fog is frequent on the plains in the cold season.
Natural vegetation has been greatly reduced by agriculture. The fauna, partly introduced, includes red and roe deer, also indigenous animals, such as the fallow deer and moufflon. Other mammals present are the wildcat, badger and squirrel. One of the region's most important wetlands is Punte Alberete, between Ravenna and the Comacchio valley, characterized by an abundance of marshland vegetation with predominantly forest trees on the dunes and aquatic flora in the hollows. This is probably one of the most extensive and remarkable waterlogged forests in Italy, whit white poplar, white willow, elm, ash and many other trees.