title: Sustainability assessment and comparison of efficacy of four P-inactivation agents for managing internal phosphorus loads in lakes: sediment incubations

authors: Gibbs, Max M.

subjects: lake restoration

abstract: A novel application of a continuous flow incubation system (CFIS) was used to assess four phosphorus (P) inactivation agents—alum, Phoslock™, a new modified zeolite (Z2G1 or Aqual-P™), and allophone—when used as sediment capping agents to manage internal P loads in lakes. The CFIS technique allowed combined efficacy and sustainability assessment, including: (1) flux measurements during simulation of stratified (anoxic) and mixed (aerobic) conditions on the same sediment through multiple cycles to assess the longevity of a range of product doses; (2) simulation of a summer algal bloom collapse and subsequent burial of the products; and (3) investigation of non-target effects on nitrification and denitrification processes at the sediment–water interface. Minimum P-removal dose rates were found to differ substantially at 80 g m⁻² for alum, 190 g m⁻² for Z2G1, 220 g m⁻² for allophane and 280 g m⁻² for Phoslock™, for similar capping layer thickness of about 2 mm, and would be effective for at least 4 years. All products temporarily suppressed nitrification and denitrification under aerobic conditions, and it may be important to minimise product application to any permanently aerobic zones, such as the littoral areas of a lake. While the aluminium (Al)-based products did not enhance Al fluxes in the CFIS, lanthanum (La) was released at a near constant rate of around 2 mg La m⁻² day⁻¹ from the Phoslock™ treatments over a period of at least 14 days. Spatial variability of sediment P, bioturbation, and burial are factors that will affect up-scaling these results to a whole lake.

text: Sustainability assessment and comparison of efficacy of four P-inactivation agents for managing internal phosphorus loads in lakes: sediment incubations A novel application of a continuous flow incubation system (CFIS) was used to assess four phosphorus (P) inactivation agents—alum, Phoslock™, a new modified zeolite (Z2G1 or Aqual-P™), and allophone—when used as sediment capping agents to manage internal P loads in lakes. The CFIS technique allowed combined efficacy and sustainability assessment, including: (1) flux measurements during simulation of stratified (anoxic) and mixed (aerobic) conditions on the same sediment through multiple cycles to assess the longevity of a range of product doses; (2) simulation of a summer algal bloom collapse and subsequent burial of the products; and (3) investigation of non-target effects on nitrification and denitrification processes at the sediment–water interface. Minimum P-removal dose rates were found to differ substantially at 80 g m⁻² for alum, 190 g m⁻² for Z2G1, 220 g m⁻² for allophane and 280 g m⁻² for Phoslock™, for similar capping layer thickness of about 2 mm, and would be effective for at least 4 years. All products temporarily suppressed nitrification and denitrification under aerobic conditions, and it may be important to minimise product application to any permanently aerobic zones, such as the littoral areas of a lake. While the aluminium (Al)-based products did not enhance Al fluxes in the CFIS, lanthanum (La) was released at a near constant rate of around 2 mg La m⁻² day⁻¹ from the Phoslock™ treatments over a period of at least 14 days. Spatial variability of sediment P, bioturbation, and burial are factors that will affect up-scaling these results to a whole lake.

year: 2010

title: Water flow between Ohau Channel and Lake Rotoiti following implementation of the diversion wall part B

authors: Hamilton, David P.

abstract: To help improve water quality in Lake Rotoiti, a diversion wall was completed in July 2008, to divert the water emanating from the Ohau Channel towards Okere Arm in Lake Rotoiti. The objective was that this water would be directly transported into the Kaituna River instead of entering the main basin of Lake Rotoiti. A report was produced in response to a request from the Rotorua Lakes Technical Advisory Group to determine water velocities in the region of the wall, to consider the effectiveness of the diversion. This subsequent report has been written to follow-up on the recommendation that vertically resolved measurements of water current and direction in Lake Rotoiti should be investigated. The timing of the data collection was April to May when an underflow is more likely to be present.

text: Water flow between Ohau Channel and Lake Rotoiti following implementation of the diversion wall part B To help improve water quality in Lake Rotoiti, a diversion wall was completed in July 2008, to divert the water emanating from the Ohau Channel towards Okere Arm in Lake Rotoiti. The objective was that this water would be directly transported into the Kaituna River instead of entering the main basin of Lake Rotoiti. A report was produced in response to a request from the Rotorua Lakes Technical Advisory Group to determine water velocities in the region of the wall, to consider the effectiveness of the diversion. This subsequent report has been written to follow-up on the recommendation that vertically resolved measurements of water current and direction in Lake Rotoiti should be investigated. The timing of the data collection was April to May when an underflow is more likely to be present.

year: 2010

title: Toitū Te Whānau, Toitū Te Iwi: A Community Approach to English Transition

authors: Berryman, Mere

subjects: Maori

abstract: The research project presented in this thesis documents and describes the outcomes of effective whānau (immediate and extended family), kura (school), student, and researcher collaboration. The researcher became part of a whānau-of-interest (Bishop, 1996b) in 1998 and 1999 when she was invited by this community to help develop a suitable programme to assist highly competent Māori immersion students in their transition to a bi-lingual secondary school (the only option available in their community). The whānau wanted students to begin their secondary schooling with an improved competence in reading and writing in English but without compromising their competency in Maori language. Prior to this programme few of the students had received any formal instruction in the English language.
After a ten-week intervention implemented mainly outside the classroom, the researcher found that whānau tutors had effectively implemented the programmes and that all Year 8 students were able to read stories (in English) and talk about them (in English) at age appropriate reading levels. They also displayed improved rates of writing in English while maintaining their high fluency in reading and writing in Māori. The 10-week programme and results were replicated over a further three terms with the Year 7 and again with the Year 6 students. The study employed a multiple baseline across groups, design. A collaborative story gathered from participants at the end of the programme, together with these process and outcome data, strongly support the successful outcomes of this "participant driven" (Bishop, 1996b) programme.

text: Toitū Te Whānau, Toitū Te Iwi: A Community Approach to English Transition The research project presented in this thesis documents and describes the outcomes of effective whānau (immediate and extended family), kura (school), student, and researcher collaboration. The researcher became part of a whānau-of-interest (Bishop, 1996b) in 1998 and 1999 when she was invited by this community to help develop a suitable programme to assist highly competent Māori immersion students in their transition to a bi-lingual secondary school (the only option available in their community). The whānau wanted students to begin their secondary schooling with an improved competence in reading and writing in English but without compromising their competency in Maori language. Prior to this programme few of the students had received any formal instruction in the English language.
After a ten-week intervention implemented mainly outside the classroom, the researcher found that whānau tutors had effectively implemented the programmes and that all Year 8 students were able to read stories (in English) and talk about them (in English) at age appropriate reading levels. They also displayed improved rates of writing in English while maintaining their high fluency in reading and writing in Māori. The 10-week programme and results were replicated over a further three terms with the Year 7 and again with the Year 6 students. The study employed a multiple baseline across groups, design. A collaborative story gathered from participants at the end of the programme, together with these process and outcome data, strongly support the successful outcomes of this "participant driven" (Bishop, 1996b) programme.

year: 2001