No.12 2005

DIY flood helps urban stream restoration
Measurements of water speed being taken during the experimental flood.
Ever wanted to create your own flood? NIWA scientists in Christchurch have done just that.
In some parts of the country, councils are replanting the banks of degraded streams, and even re-establishing submerged aquatic plants. Native vegetation should benefit urban streams by stabilising banks, filtering contaminants, and providing shade, food, and habitat.

Guidelines for cleaner water
How can farmers help reduce faecal contamination of freshwaters? We have been working on a collaborative research programme for the Ministry of Agriculture and Forestry, looking at how faecal microbes get from farm animals to waterways.
Grazing livestock are a major source of faecal contamination, which can pose a health risk to swimmers and restrict shellfish aquaculture.

Water resources outlook (July - September)
The following soil moisture levels & river flows are likely:
East of the North Island
Normal soil moisture levels; normal or below normal streamflows
East of the South Island
Normal or below normal soil moisture levels and streamflows
Elsewhere
Normal river flows and soil moisture levels

NIWA Advanced Pond Systems NIWA offers a complete scientific, engineering, and project management service for Advanced Pond Systems:
Consistently higher effluent quality than conventional ponds Minimal odour compared with conventional treatment Simple operation and maintenance Construction and operating costs typically less than half that of mechanical treatment plants Environmentally sustainable, with significant potential for energy and nutrient recovery
www.niwa.co.nz/rc/pollution/aps

Another P problem
NIWA researchers have found a disturbing national trend of increasing phosphorus (P) levels in rivers draining farmland.
The finding mirrors earlier work on increasing nitrogen levels, and is based on data from NIWA’s National River Water Quality Network for the years 1989 to 2003. We found a strong association between the size of the increases in dissolved phosphorus and the amount of pastoral land use in the river catchment. Increasing levels of both nitrogen and phosphorus may lead to more nuisance algal blooms in rural waterways.

Water resources review (April - June)
River flows
River flows were well below normal for most of the country, except for the east coast of the North Island and the south of the South Island, where they were normal to above normal.