In 2012 Water Technology and GeoLink were commissioned by the Coffs Harbour City Council to undertake an Estuary Management Plan and Hydraulic Assessment of the Coffs Creek estuary which runs along the boundary of the main centre of Coffs Harbour.
The estuary is a tranquil oasis on the edge of the city and is utilised by residents and visitors in increasing volumes. An Estuary Management Plan was undertaken to identify and assess management options for the estuary going forwards. In addition, the free passage of flood flows through the estuary was identified as a potential contributor to the severe flooding experienced in the city centre during flood events.
A hydraulic model of the estuary was established and calibrated to measured water levels at the upstream and downstream ends of the estuary. Modelling of a range of management options, including reduction in fringing mangrove density and spread, dredging of the flood tide shoals and tidal entrance channel were assessed.
The runoff from the urban and industrialised sections of the catchments had been studied previously and the information from these works were used to determine potential improvements in the water quality which could be made by strategic upgrade of drainage and water quality systems.
The results of the Hydraulics Assessment were used to help prioritise the management options and to provide the Council and local community of Coffs Harbour with a wealth of information on the drivers of estuary health in their town.