The rivers and streams of the Chatham Islands are relatively short, and rain-fed systems that reflect the region’s low-lying topography and peaty soils. These waterways flow through unique landscapes of coastal scrub, wetlands, and farmland before draining either directly to the coast, to lakes or into the large Te Whanga Lagoon. These systems support important ecological, cultural, and community values.
Freshwater environments on the island range from shaded bush streams to open watercourses influenced by land management and stock access. Sediment and nutrients are affected by both natural conditions and human activities, such as farming and vegetation clearance.
Water quality monitoring is operated by Environment Canterbury in partnership with the Chatham Islands Council. Routine monitoring began in 2005 and includes sampling at a selected range of streams and rivers across Chatham Island. These sites are sampled quarterly, providing a consistent long-term dataset for assessing the state and trends of freshwater quality across the island.
Key indicators such as nutrients (nitrogen and phosphorus) and bacterial levels are monitored to understand how water quality changes in response to land use, geology, and climate.
E. coli, clarity and turbidity data may be missing from some sites as these indicators are not routinely sampled.
