An assessment of biophysical effects of different catchment management scenarios on the Te Whanganui-a-Tara Whaitua coastal environment indicated that ‘business as usual’ will result in ongoing environmental degradation, particularly within estuaries. Current state conditions will be maintained or improved under the ‘improved’ scenario, although not within a generation. Further small improvements to ecological health relative to current state are expected under the ‘water sensitive’ scenario. The most significant predicted improvements are expected for human health and recreation from a reduction in pathogen inputs to the coast. Improvements should be maximised by incorporating land use changes and novel mitigation methods into future scenario planning