Sediments
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Nutrient spiralling study in the Tukituki River, Hawkes Bay
Intensive land use increases nutrient runoff to rivers, lakes and estuaries with adverse effects on ecosystems. Determining what combinations of land use and management enable the health and services of these ecosystems to be maintained or restored is a major challenge for councils.
The Kaipara: big research for a big place
Catchment modelling of sediment loads to estuaries
Estuary sedimentation is a continual natural process. Land slope, land use, soil type and rainfall all have significant impacts, and form a complex spatial pattern of sediment generation.
Tracking water age in hydrological models
Benthic fauna thrives in fishing exclusion zone
Research has revealed key differences in seafloor communities and habitats inside and outside the Separation Point trawl fishing exclusion zone in Tasman Bay. These have important implications for valuable benthic fisheries in the area.
Tauranga Harbour sediments in 2051
What will future land use and climate change do to sediments entering southern Tauranga Harbour? To find out, Environment Bay of Plenty commissioned NIWA to model the sources and fates of sediments under various scenarios over a 50-year period.
Preparing for land-use change in the Upper Motu catchment
The Motu River, in the eastern part of North Island, is the first of NZ’s so-called ‘wild and scenic rivers’. However, its upper catchment seems likely to be the focus of dairy expansion. NIWA scientists have been looking at the likely impacts of this change in land use.
Reducing contaminant runoff from roads
Heavy metals, released by wear on tyres and brake pads, are washed off roads and can contaminate rivers, streams and harbours. NIWA has recently completed a study to measure how much copper and zinc is discharged in road runoff, and how well different stormwater devices remove these contaminants from runoff.
Could climate change affect infectious diseases?
NIWA scientists are part of a team hoping to answer questions about how climate change might affect disease rates in New Zealand, such as those caused by pathogens like Cryptosporidium and Campylobacter, two major causes of disease in New Zealand.
Recent water quality information
Water temperature and clarity information, April to June 2010.
Retrospective river flows, April to June 2010
Our last three-monthly predictions, and what actually happened.
River flows update, July 2010
Monthly and seasonal river flow information, and our outlook for the coming three months.
The long walk - assessing stream health in Waitakere
Walking the whole length of streams is slow and difficult, but by far the best way to learn about their environmental condition.
Predicting long-term contamination in estuaries
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.