Investigations were undertaken at the point where the via Annia crossed the river on a bridge which was discovered in 1883 and destroyed at the beginning of the 20th century. Following several sporadic finds in the area ( ranging in date to between the 5th century B.C. and the 2nd century A.D. all of very similar type but which could not be linked to a precise settlement type) the decision made to undertake new investigations with the aim of tracing the course of the road and ascertaining the existence of a riverside settlement. Trial trenches were opened on the river’s left bank; given the fragmentary nature of the evidence in this sector research was concentrated on the recovery of further information regarding the bridge. This investigation also highlighted several problems. However, the excavation recovered new data regarding the ancient structure of the Grassaga canal which suggests that in the Roman period the river was controlled by a series of interventions on long stretches of its left bank which probably aimed to raise its level with respect to the riverbed. Considering the fact that in this part of the territory the river flowed into the lake, it is plausible to suggest that these interventions were intended to prevent the flooding to which the area was subject and also to render the canal navigable thus creating a passage inland from the sea. (Elena Pettenò)