No.22 2007

CLUES to impacts of land-use change
 
The "CLUES" toolbox in ArcMap, displaying nitrate loads from a model run together with a sub-window showing nitrate leaching risk in that area.
A team of scientists from AgResearch, NIWA, Landcare Research, HortResearch, Harris Consulting, and Aqualinc Ltd., continue to develop a powerful new tool to help predict the impacts of land-use changes on water quality and socio-economic indicators.

Irrigation modernisation
Irrigation schemes that use canals for water distribution have been contributing to farming productivity for thousands of years. A considerable area of farmland is supplied by such schemes in New Zealand. As farming has become more intensive, the need for canal irrigation schemes to deliver water in a way that closely matches on-farm needs has increased.
New Zealand’s canal-based irrigation schemes are generally owned and managed by water users.

Models to help manage erosion
Managing land erosion, and subsequent sedimentation in streams, lakes, and coastal areas, is a big headache for many local authorities. At two recent workshops, NIWA and Landcare Research joined with land-use managers to explore ideas of how computer models might help resolve some of the issues faced.
Major environmental problems identified included estuarine infilling, pasture and soil degradation, sediment affecting water quality, and fine sediment altering stream-bed habitat.

Water resources outlook (May - July)
The following soil moisture levels & river flows are likely:
Northern North Island: Normal soil moisture levels and river flows are likely.
Southeastern North Island: Below normal soil moisture levels and normal or below normal river flows are likely.
Northern and southwestern South Island: Normal soil moisture levels and river flows are likely.
Eastern South Island: Below normal soil moisture levels and river flows are likely.

Water resources review ( February-April)
River flows
 
February – April river flows
River flows were well above normal in Northland, mainly as a result of the severe flood events in April. Some central North Island catchments had normal river flows for this time of year, but flows were below normal for the rest of the country. Record low flows occurred for some rivers in Marlborough, the Southern Alps, and Southland.
[Water resources information provided by NIWA field teams, regional and district councils, and hydropower companies.]

What value a stream’s ecology?
 
Development affecting an Auckland stream. (Photo: Stephen Moore, Landcare Research)
Several kilometres of stream habitat are lost each year to development in the Auckland region. Developers are often asked to fund the improvement of stream habitats at a different site, thus offsetting the ecological damage they have caused.