The story of water quality in New Zealand dates back to the beginnings of European settlement and can be broken down into the gradual emergence three pollutants: pathogens, sediment and nutrients.
In the 1800s the problem was pathogens – the bacteria that make us sick – largely stemming from untreated sewage running into urban streams. In 1862 one out of every three people in Cromwell was infected by typhoid.
An historic legacy of deforestation, erosion and sedimentation has irreversibly changed many catchments. Sediment makes water murky, smothers aquatic life, alters water flows and exacerbates flooding.
Over time, factories, freezing works and sewage schemes have all contributed to increasing levels of nutrients in our waterways. In more recent years, changing land use and the rapid expansion of dairy farming has greatly exacerbated the problem.