Controlling inputs from the land to sea: limit-setting, cumulative impacts and ki uta ki tai

Abstract

The coastal zone worldwide is not well served by management policies that fail to deal effectively with land-sourced contaminants from streams, rivers and urban runoff. We discuss this using examples from New Zealand, where there is a wide recognition of such problems but little effective policy that specifically accounts for the interconnectedness of the land-to-freshwater-to-sea domain. Increasing land-use intensification, mostly in arable pasture, has greatly increased the nutrient load to the coast and has contributed to the already high sediment loading of coastal waters. We argue that renewed effort is needed for a more holistic approach to management, encapsulated in the New Zealand Maori concept of ki uta ki tai – an appreciation of mountains-to-sea connections. Limit-setting, especially of nitrogen from terrestrial sources, seems to a main way forward for reducing loads and halting cumulative effects. However, this must account for current impacts and also the ‘load to come’ because of time lags associated with accumulated groundwater nutrients and cumulative impacts in receiving waters. Despite many approaches being tried, there are increasing impacts of catchment activities on coasts worldwide. The need is therefore great for new approaches, renewed effort, and for a very long-term perspective to ensure effective and enduring solutions.