New Zealand’s estuaries are a receptacle for a steady stream of contaminants from the land. We tend to manage these pressures reactively, determining on a case-by-case basis whether proposed activities in the catchment will have adverse effects in estuarine receiving waters. Proposed activities are often assessed individually, but it is the sum total of all activities – past, present and anticipated – that really causes the damage.There is another way to manage these cumulative effects, which involves deciding on limits to use of the receiving water body, and then allocating “rights to pollute” until the limit is reached. This “capacity-allocation” approach is being used to manage nutrient problems in the Central North Island lakes and has resulted in radical changes in how the land is managed, including some severe proscriptions on certain land uses, and the creation of a market for trading nutrient allocations.No similar approach is currently in use in any estuaries in New Zealand.Can we afford not to be thinking in this way? Isn’t it time that we got serious and drew some lines in the sand about how we want our estuaries to be? How do we reconcile competing values? What are the technical issues? What innovations could see productive land and healthy estuaries co-existing? And, assuming we eventually get that far, are we bold enough to manage the land within strict limits to deliver our aspirations for the marine environment?Speaker: Malcolm Green is a Principal Scientist working on coastal processes at NIWA, in Hamilton, and winner of the Kudos Environmental Science award in 2009.