No.06 2004

First use of whole lake alum treatment in New Zealand
Lake quality criteria in Environment Bay of Plenty’s Water and Land Plan indicate that five of the region’s lakes need improvement. A number of remedial methods are being investigated and trialled. Lake Okaro, near Rainbow Mountain, has the poorest quality of the Rotorua lakes and is small enough (33 hectares) for alum treatment to be tried to precipitate and inactivate phosphorus.

NIWA completes development of New Zealand River Environment Classification
River Environment Classification for stream channels in an area of 125 km2 just northwest of Invercargill (A). Small coastal streams draining low-lying swampy areas (blue and purple) are distinguished from larger streams that drain larger areas of other landscapes.

Groundwater time delay in the Lake Rotorua catchment
Environment Bay of Plenty is undertaking a study with the Institute of Geological and Nuclear Sciences (GNS) to understand the groundwater delays within the catchment of Lake Rotorua. This work is vitally important for understanding land-use effects on Lake Rotorua.

The Rotorua Lakes Protection and Restoration Action Programme
Rotorua’s twelve stunningly beautiful lakes have been under pressure from human activities for many decades.

Managing Te Roto o Wairewa: lessons from its past
Te Upoko o Tahumata te mauka
Okana te awa
Wairewa te roto
Tahumata iss the mountain
Okana is the river
Wairewa is the lake
Te Roto o Wairewa (Lake Forsyth) and its catchment on the southwest margin of Banks Peninsula.
Te Roto o Wairewa (Lake Forsyth) is a shallow coastal lake on the southwest of Banks Peninsula. The lake is turbid due to high algal production and wind driven sediment resuspension.

Water resources in summer 2003-04 (December 2003 to February 2004)
River flow
River flows for summer were far above normal in many parts of the North Island, near normal in the west of the South Island, and below normal in the east of the South Island. For some rivers in the Manawatu–Wanganui and Taranaki regions, these are the highest summer flows on record, and are a direct result of the February storms. This is a marked contrast to the previous summer, when summer flows were unusually low.