Development Application - Part 2 of 2 - Report & Plans · OPW11/0116

1.   BACKGROUND

The Noosa River estuary is a highly modified system. In its natural configuration, the entrance is very dynamic and variable.
During calm periods the river meandered substantially and flood events resulted in a straight channel direct to the ocean,
placing the entrance close to the end of Hastings Street [Figure 1].




Figure 1: BPA aerial photos of natural Noosa River configurations - 1940 [calm weather] & 1972 [post-flood]

In 1977, the BPA report "Scheme for the Protection of Hays Island and Restoration of Noosa Beach" stated that the
southern channel had developed to such an extent that it carried almost the entire flow of the river. Severe erosion of Hays
Island was then occurring along the northern revetment. In response to this problem, BPA proposed to relocate the river
mouth to the north and reclaim Noosa Spit. "The function of this scheme is to separate the main body of flow of the Noosa
River from Hays Island which is under threat of erosion and which requires protection.         The scheme will also provide
secondary benefits in the form of restoration and lengthening of Noosa Beach." The works were undertaken in 1978 [Figure
2].




Figure 2: BPA aerial photo of completed works [19831

Since reclamation of Noosa Spit, the behavior of the river has remained highly variable in response to changing conditions.
The river meanders predominantly to the south [but periodically to the north] during calm conditions with a more direct
"middle channel" developing during high flow conditions associated with cyclones and floods [Figure 31.