The Clarence River has a catchment area of some 21,900 square kilometres to its mouth at the Pacific Ocean and some 19,800 square kilometres to Grafton. The catchment is bounded to the west by the Great Dividing Range, by the Doughboy Range / Dorrigo Plateau to the south and the Great Dividing Range / McPherson Range to the north. The Richmond Range and the Coast Range separate the smaller coastal catchments from the Clarence River.

Iluka is approximately five kilometres upstream of the river’s mouth and is partially separated from the mainriver by large breakwaters. The mouth of the Clarence River is restricted by a northern and southern breakwater which are up to 500 min length and several metres high. The objectives of this Plan are:

• to review the nature and extent of the flood hazard in light of the recently completed Lower Clarence River Flood Study Review (March 2004),
• to review the existing management measures aimed at reducing the impact of flooding on both existing and future development,
• to develop a Plan that addresses the current and future flooding issues for the township of Iluka.