The Inner Hauraki Gulf/Tīkapa Moana ecosystem is facing proliferations of algae, de-oxygenation, reduced pH (acidification), reduced water clarity, and muddier sediments arising from historical and future land-derived contaminant inputs.
Constructed wetlands, detention bunds, woodchip denitrification filters and planted riparian buffers are examples of a growing suite of edge-of-field and farm-scale mitigation systems that are being trialled across rural New Zealand to reduce the impact of diffuse pollution on freshwater quality
The Whatawhata Integrated Catchment Management (ICM) Project is the longest continuously monitored before-after-control-impact (BACI) catchment-scale study in New Zealand.
While we know that glaciers are sensitive to changes in their local climate, our understanding of exactly how mountain glaciers will respond to climate change is incomplete.
NIWA has established a network of 11 high elevation meteorological stations aiming to gather information about the amount, extent, seasonal nature and long-term change to snow and ice in alpine regions of New Zealand.
The alp-fed braided rivers of Canterbury are treasured for their landscape, recreational amenities, salmon- and trout-fishing, and unique riverine environments – which provide habitat to a host of endangered birds – but they are under threat from land-use intensification and a growing demand for irrigation water.
Of the more than 70 aquatic plant species naturalised in New Zealand, more than 75% have become problem weeds or have been assessed as having the potential to become future problem weeds. Most of our lakes, rivers and streams are affected by at least one of these species.
Braided rivers are an arena where woody weeds and floods are in constant competition with each other.
Braided rivers naturally flood frequently, repeatedly mobilising their bed sediments and shifting their multiple channels.
Most of the plastic in the ocean originates on land, being carried to the estuaries and coasts by rivers. Managing this plastic on land before it reaches the river could be the key to stemming the tide of marine-bound plastics. The aim of this project is to understand the sources and fate of plastic pollution carried by urban rivers using the Kaiwharawhara Stream as a case study.
Currently there are gaps in understanding of user decision making processes and public needs and requirements for river forecasting in New Zealand. This project aims to bridge NIWA river forecasting aspirations and capabilities with both the public and decision makers’ requirements.
Bringing together leading scientific organisations and regional councils, this project aims to develop a sophisticated computer modelling framework that will enable users to accurately predict how much freshwater is available, where it has come from, and how quickly it moves through New Zealand catchments.
Excessive nutrient input (eutrophication) threatens many New Zealand estuaries causing ecological problems, such as algal blooms and poor physical and chemical conditions for estuarine life.
NIWA is undertaking a five-year nationwide study to find out how different approaches to riparian planting influence water quality improvements and to provide better guidance to the people and groups undertaking stream restoration.
NIWA is developing numerical models for predicting how the morphology of braided rivers responds to flow regulation and invasive exotic woody vegetation.
This project investigated the capabilities and utility of NIWA’s Cumulative Hydrological Effects Simulator (CHES) tool for facilitating discussions and decision making associated with setting and applying water quantity limits in the Grey River catchment on the South Island’s West Coast.
