No.27 2008

Protecting our aquatic environments
Waikanae River (Photo: Alan Blacklock, NIWA)
“Environmental problems in our waterways associated with land-use change, or land-use intensification, are rarely caused by a single factor,” says NIWA’s Dr Malcolm Green, leader of a research programme aimed at protecting aquatic environments.
“Changes such as conversion of forestry to pasture, or increased irrigation take, can fundamentally affect life in our streams, rivers, lakes, and estuaries,” says Malcolm.

Multiple stressors and aquatic life
The field trial site. (Photo: Jeremy Piggott, University of Otago)
How do increases in levels of nutrients and fine sediments, higher water temperatures, and reduced water flow, affect life in streams? What if these changes occur simultaneously?

Water resources outlook (June–August 2008)
Northern and southwestern North Island
Normal or above normal soil moisture levels and river flows are likely.
Southeastern North Island; east & southwest South Island
Normal soil moisture levels and normal or above normal river flows are likely.
All of the South Island
Normal soil moisture levels and river flows are likely.

Storm chasing - understanding sediment generation and transport
Sediment in the Raglan estuary following a January storm. (Photo: Sandy Elliott, NIWA)
NIWA scientists have been out in the rain, monitoring the impact of storms on sediment erosion and transport.

Water resources review (March– May 2008)
River flows
March– May 2008 river flows
River flows over the last three months were above normal in Northland and the Bay of Plenty, normal in the central North Islandand Hawke’s Bay, and below normal everywhere else.
[Water resources information provided by NIWA field teams, regional and district councils, and hydropower companies.]