As part of the Beach Protection Strategy (ICM, 1997) a submerged reef was constructed at Narrowneck (Gold Coast, Australia). This reef has to act as a shoreline control point and to provide improved surfing conditions. The construction was completed in January 2001, but adjustments in the design are still possible depending on its functioning. The critical question designing the reef was whether a salient would form or a tombolo. In order to monitor shoreline changes at the Northern Gold Coast, an ARGUS coastal imaging system was installed in 1999. The first objective of this study is to apply a new image analysis technique at the Northern Gold Coast imaging system and assess the performance of this technique. This technique developed at Delft Hydraulics enables to assess quantitatively intertidal beach variability. A second objective is to determine the effectiveness of the reef structure to provide a shoreline control point carrying out intra-annual intertidal beach mapping. The third goal is to predict long-term shoreline response as a result of different wave transmissions over the reef and to find criteria, which indicate the performance of the reef to enhance and stabilise the Northern Gold Coast beach. The one-line shoreline model GENESIS is used applying an updated mapped shoreline and survey data (giving information about the position and dimensions of the reef as constructed). The new image analysis technique (Intertidal Beach Mapping) was put into operation for the Gold Coast imaging site setting up pre- and post-processing routines. This has resulted in a Plan of Operation for the Gold Coast site indicating how this technique can best be operated. Validation of the technique has given new insight in the sensitivity of the technique to site-related luminance and colour characteristics. It further shows that the accuracy of the technique is very acceptable to quantify volume changes in the Intertidal Beach: Typical mean errors in the quantified intertidal beach variability are in the order of 15 30 %. From intra-annual intertidal beach mapping (January 2000 - April 2001) two dominating features could be discerned: storm-based erosion events and migration of nourishment northwards. This shows that the technique is able to identify and follow morphological changes at the beachfront. Shoreline modelling has resulted in a number of plots showing the extent of shoreline response at the Gold Coast for different wave transmissions. An effective wave transmission in the order of 70% seems to be desirable. Evaluation of the modelling results suggests that the simulated accretion / erosion are upper limits. More dispersion is expected (considering the interaction of a range of 3-D physical processes) smoothing out the simulated shoreline changes. The main conclusions concerning the Narrowneck Reef: So far (April 2001), the effectiveness of the reef to provide a shoreline control point has not been detected in Argus video images. However, the cumulative accretion in the lee of the reef (relative to July 2000) may indicate the initial stage of a salient formation. Predictive numerical modelling show that the formation of a salient will result in the increase of the beach width up to approximately 1000 m south of Narrowneck. The most important recommendations for the near future: * Continue monitoring (considering as well the control and prevention as scientific purposes.) * Measure the effective wave transmission of the reef to assess the effectiveness of the structure to shoreline response. Then, a cost-benefit analysis can be made to decide whether the crest level should be raised. * Facilitate the operation mode of the imaging technique with e.g. standard pre- and post-processing routines and a user-manual. * Investigate the physical character and consistency of the mapped shoreline (alongshore) in relation with site-related varying colour and luminance characteristics