A study on the benefits of street sweeping for reducing stormwater contaminant loads to streams has been completed for Nelson City Council (NCC). The study found that properly designed street-sweeping programmes can reduce contaminant loads in catchments by approximately 30 per cent.
A recent study by NIWA has identified levels of some emerging contaminants around the Auckland marine environment that are similar to those measured in other industrialised countries.
What are emerging contaminants?
On-site disposal of poorly treated household wastewater can be a significant source of pollution in ground and surface water.
What we predicted for July 2011 to September 2011
River flows are likely to be normal in the North Island and north of the South Island, and normal or below normal in the rest of the South Island.
What actually happened during July 2011 to September 2011
River flows were normal to below normal for most of the country, with some above normal river flows in the eastern North Island, eastern Southland and coastal Otago.
Monthly and seasonal river flow information and our outlook for the coming three months.
September 2010 river flows
Click on the map to enlarge
River flows, July to September 2011
Cumulative flows over the three months, July to September 2011. Click on the map to enlarge
Outlook by region, July to September 2011
Seasonal data from the National River Water Quality Monitoring Network.
We are regularly adding new material to our website. Here are a few examples.
Abstracting water from rivers is likely to cause changes in river flows, endangering habitats and making supply unreliable for downstream users. NIWA is working to develop river flow rules that can be applied at a local level to prevent these problems.
During summer the concentration of oxygen in the bottom waters, or 'hypolimnion' of Lake Taupo decreases. To find out what factors are responsible for the total oxygen decrease, NIWA scientists have been monitoring the inputs and outputs of oxidisable matter to the lake.