The Sacca di Goro is a shallow-water embayment of the Po River Delta approximately triangular in shape with a surface area of 26 Km2, an average depth of 1.5 m, and it is connected to the sea by two mouths about 0.9 Km wide each. The lagoon is characterized by a clear zonation with the low energy eastern area separated from two higher energy zones, the western area influenced by freshwater inflow from the Po di Volano and the central area influenced by the sea The eastern zone is very shallow (maximum depth 1 m) and accounts for one half of the total surface area and one quarter of the water volume. The lagoon is surrounded by embankments. The main freshwater inputs are the Po di Volano River, the Canal Bianco and Giralda, which have approximately the same discharge rates. Freshwater inlets are also located along the Po di Goro River and are regulated by sluices. There are no direct estimates of the freshwater input from the Po di Goro, which is usually assumed to be equivalent to that of the Po di Volano. The freshwater system is mostly located in a subsident area and is regulated by a system of pumping stations (scooping plants). The fresh water or hydraulic residence time oscillates monthly between 2.5 and 122 days with a mean value of 24.5 days, whereas the water exchange time ranges from 2 to 4 days. The tidal amplitude is ca 80 cm. The bottom of the lagoon is flat and the sediment is alluvial mud with high clay and silt content in the northern and central zones. Sand is more abundant near the southern shoreline, whilst sandy mud occurs in the eastern area.