Technical Reports

Listed are several technical reports regarding the Rotorua Lakes:

Biomanipulation

Review for the potential for biomanipulation of phytoplankton abundance by freshwater mussels in the Rotorua lakes NIWA

Using plants (algae) to strip nutrients from streams and lakes. - Warwick Silvester, Dept of Biological Sciences, University of Waikato, Hamilton.  24 October 2006

Economics

An economic evaluation of land use change options - Nimmo-Bell
Section A - Cost-benefit and opportunity cost analysis - Lake Okareka
Section B - Economic impact on Rotorua district and Bay of Plenty region of water-quality induced changes to land use and tourism in the Rotorua Lakes catchments

Economic Evaluation of Water Quality Induced Changes in Rotorua and Rotoiti Catchments Nimmo-Bell
   Part a) Land Use Change Scenarios
   Part b) Macro-Economic Implications

Engineering Options

Summary Report on Possible Dredging of Lakes in the Rotorua District - Analytical & Environmental Consultants, February 2007

Impact of the Ohau Channel Diversion on Okere Arm, Kaituna River and Maketu Estuary - John McIntosh, Environment Bay of Plenty

Hypolimnetic Discharge Environment Bay of Plenty

Lake Rotoiti Fieldwork and Modelling to support considerations of Ohau Channel Diversion from Lake Rotoiti - David Hamilton, Chris McBride & Toradji Uraoka - Centre for Biodiversity and Ecology Research, University of Waikato

Lake Rotoiti - Ohau Channel Diversion Feasibility Study Tonkin & Taylor
 - Diversion Option 1
 - Diversion Option 2
 - Diversion Option 3

Modelling diversion walls for diverting the Ohau Channel inflow from Lake Rotoiti Scott Stephens, NIWA

Ohau Channel Groynes

Rejuvenating Lake Rotoiti BOC Ltd

Supplement to Lake Rotoiti diversion wall modelling - refined wall designs and response to peer review Scott Stephens. 
A response to the Dr John List’s peer review of “Modelling diversion walls for diverting the Ohau Channel inflow from Lake Rotoiti”.

Tikitere Flow Diversion Report Rotorua District Council

Fisheries

Lake Okareka and Tikitapu Fish Health Monitoring 2007 - Michael Landman, Jeroen Brijs, Chris Glover and Nicholas Ling, 30 October 2007

Implications of introducing Grass Carp into the  Rotorua Lakes - Matt Bloxham, Environment Bay of Plenty

Baseline study of the potential impact of increased trout numbers in the Kaituna River on whitebait (migrant galixiids) - NIWA, November 2005

Potential effects on smelt of diverting Ohau Channel water out of Lake Rotoiti - NIWA, November 2006

The Hamurana Stream in Lake Rotorua: some potential effects of its diversion on the trout fishery and on summer nutrient dynamics - NIWA, June 2005

Effects of the cold, spring-fed, inlet streams on Rainbow Trout distribution in Lake Rotorua - NIWA, September 2006

Implications of Introducing Grass Carp into the Rotorua Lakes Environment Bay of Plenty

Kaituna River Fish Inventory NIWA

Lake Okareka and Tikitapu fish health monitoring 2006: Trout baseline study, April Michael Landman, Nicholas Ling and Trevor Stuthridge

Lake Okareka Fish Health Monitoring 2005 Michael Landman, Mike van den Heuvel and Trevor Stuthridge

Lake Okareka and Tikitapu Fish Health Monitoring 2006 Michael Landman and Nicholas Ling

Flocculants

Phoslock Application - Lake Okareka Final Report Prepared by John McIntosh, Environment Bay of Plenty

Lake Okareka and Tikitapu Fish Health Monitoring 2007 - Michael Landman, Jeroen Brijs, Chris Glover and Nicholas Ling - Scion

P-inactivation efficacy of Z2G1 as a capping agent on Lake Okaro sediment - NIWA

Melter slag sox at a Rerewhakaaitu stream (Report 1) R. W. McDowell and M. F. Hawke

Melter slag sox at a Rerewhakaaitu stream (Report 2) R. W. McDowell and M. F. Hawke

Assessment of the performance of nutrient reduction treatments for the Rotorua Lakes - Z Yang, M R van den Heuvel, T R Stuthridge

Environmental Impacts of Lake Okaro Mesocosm Trial Matthew Bloxham, Environment Bay of Plenty.

Phoslock Application - Lake Okareka John McIntosh, Environment Bay of Plenty

Locally Available Absorbing Materials, Sediment Sealing and Flocculants for Chemical Remediation for Lake and Stream Water Analytical & Environmental Consultants

Geology

Lake Okaro: Explosions and Erosion Lyndon Hardy
A study into erosion on the hills to the north of Lake Okaro and the 0.7 ka phreatic and hydrothermal eruptions at Lake Okaro to help understand the current geomorphology

Geothermal

Mixing of Tikitere geothermal discharges with sewage - GNS Science Consultancy Report, March 2006

Estimate of the geothermal nutrient inputs to 12 Rotorua lakes Bioresearches

Water quality impacts of a point-source discharge of Tikitere geothermal water in Lake Rotoiti Rotorua District Council

Groundwater

Groundwater Age and Chemistry, and Future Nutrient Loads for Selected Rotorua Lakes Catchments By U Morgenstern and others. IGNS Science Report 2004/31

Groundwater age, time trends in water chemistry and future nutrient load in the Lakes Rotorua and Okareka areas Institute of Geological & Nuclear Science

Prediction of Future Nitrogen Loading to Lake Rotorua  IGNS Science Report 2006/10

Land use management and land use change

Cost-effectiveness Analysis of Grazing Management Options for Rotorua Dairy Farms (890KB, pdf)

This report is based on a desktop exercise undertaken to scope issues and opportunities around managing nutrient loss associated with winter grazing in the Rotorua lakes catchments. The report has used conservative assumptions for the economic analysis.

Anecdotal evidence of the economic or management benefits of using covered herd shelters on dairy farms is now being further evaluated through an on-farm project. This is documenting the management and production effects of integrating of a Herdhome into an existing dairy farm in the Lake Okaro catchment.  This project started in the 2007 season and will run for 5 years. Results and experiences are being shared with farmers in the Rotorua lakes catchments through field days held at the site.

Land Use Impacts on Nitrogen and Phosphorus Loss and Management Options for Intervention AgResearch

Nitrification and Urease Inhibitors D C Edmeades, agKnowledge Limited