Land-derived sediments and heavy metals are two contaminants threatening the health of New Zealand’s estuaries. NIWA has developed the Urban Stormwater Contaminant (USC) model to predict long-term sediment and heavy metal accumulation under various land-use and management scenarios. The model has recently been applied to the Waitemata and Manukau Harbours to aid planning decisions.
Beds of New Zealand seagrass (Zostera muelleri) provide important habitat for coastal species such as small fish, seahorses, and shellfish. Much of New Zealand’s seagrass habitat has been lost or degraded, mainly as a result of sedimentation. NIWA is leading a small-scale seagrass transplantation trial in Whangarei Harbour, with promising early results.