The experimental investigation in this report was conducted both as indicator of the problems in McCormacks bay, and also as a base for the calibration of a numerical model of the hydraulic characteristics of the bay. There are some issues of public concern associated with the bay at the present time. These are related to dominant algae populations and their related problems, and the desire to preserve the existing bay as a healthy marine environment. Numerical models can be a useful tool to test various management options. A component of this study involved the calibration of a numerical model which described the response of the bay to tidal functions in the estuary. Calibration was achieved using data from measurements taken on the eighteenth of December 1996. The model was based specifically around the main central culvert running under the causeway. The model showed that an increase in the depth of this culvert would increase the range of water levels in the bay by up to 23%. This is significant and would increase the tidal exchange in the bay, thereby promoting circulation.