This national GIS ‘layer’ enables reconnaissance-scale estimation of suspended-sediment yields from New Zealand’s rivers and streams. It has been developed by NIWA in collaboration with Landcare Research.
Over the past decade, NIWA has published many popular articles that deal with estuaries - this overview is intended to bring together and make whole sense of the information published to date in the various popular articles.
Bottom lining is the installation of a flexible covering over the top of beds of aquatic weeds, similar to using weed matting in home gardens. The lining is held in place by weights (e.g., rocks or sandbags) or by pinning. This control method is also called ‘benthic barriers’.
Water quality in urban streams and stormwater systems is frequently poor and highly variable, across both space and time. Traditional monthly grab sampling is rarely adequate to characterise contaminant concentrations during wet weather events.
Diquat is a herbicide (chemical) that has been used in New Zealand for many decades for submerged (underwater) weed control and also on agricultural crops. It is registered for freshwater use in New Zealand.
The Fish Passage Assessment Tool has been developed to provide an easy to use, practical tool for recording instream structures and assessing their likely impact on fish movements and river connectivity.
The River Environment Classification (REC) is a database of catchment spatial attributes, summarised for New Zealand's river network. The attributes were compiled for the purposes of river classification, while the river network description has been used to underpin models.
The environmental effects of developing land and water for human use have decimated New Zealand's native fish fauna, but we now have the knowledge to reverse this trend and restore native fish in streams.
Habitat degradation and the introduction of exotic plant and fish species have adversely affected kōura populations throughout New Zealand. However, there are a number of measures that we can use to restore kōura populations in lakes, rivers and streams.