A levee is proposed along the southern shoreline of Pig Island to retain and drain saturated sands and silts pumped across to the island from a sand washing plant at Terrara. At the time of compiling this report, the levee is in place but incomplete. The present proposal provides for the levee to be increased in length (to the east) and raised to a crest height of between 3.57m and 3.96m AHD. Concerns have been expressed that such a levee could impact flood behaviour in the reach between Pig Island and Terrara to an unacceptable degree. This report has been commissioned to quantify these impacts. The principal objectives of this study are then to:

a. Hydraulically model the 1% and 5% AEP flood flows in the lower Shoalhaven in the vicinity of Pig Island, both with and without the levee as proposed.

b. Compare and comment on the impact of the proposed levee on flood flows ( depth and velocity) in the vicinity of the island.