title: Review of best management practices for aquatic vegetation control in stormwater ponds, wetlands, and lakes

authors: de Winton, Mary

abstract: Auckland Council (AC) is responsible for the development and operation of a stormwater network across the region to avert risks to citizens and the environment.
Within this stormwater network, aquatic vegetation (including plants, unicellular and filamentous algae) can have both a positive and negative role in stormwater management and water quality treatment. The situations where management is needed to control aquatic vegetation are not always clear, and an inability to identify effective, feasible and economical control options may constrain management initiatives. AC (Infrastructure and Technical Services, Stormwater) commissioned this technical report to provide information for decision- making on aquatic vegetation management with in stormwater systems that are likely to experience vegetation-related issues.
Information was collated from a comprehensive literature review, augmented by knowledge held by the authors. This review identified a wide range of management practices that could be potentially employed. It also demonstrated complexities and uncertainties relating to these options that makes the identification of a best management practice difficult. Hence, the focus of this report was to enable users to screen for potential options, and use reference material provided on each option to confirm the best practice to employ for each situation.
The report identifies factors to define whether there is an aquatic vegetation problem (Section 3.0), and emphasises the need for agreed management goals for control (e.g. reduction, mitigation, containment, eradication). Resources to screen which management option(s) to employ are provided (Section 4.0), relating to the target aquatic vegetation, likely applicability of options to the system being managed, indicative cost, and ease of implementation. Initial screening allows users to shortlist potential control options for further reference (Section 5.0).
Thirty-five control options are described (Section 5.0) in sufficient detail to consider applicability to individual sites and species. These options are grouped under categories of biological, chemical or physical control. Biological control options involve the use of organisms to predate, infect or control vegetation growth (e.g. classical biological control) or manipulate conditions to control algal growth (e.g. pest fish removal, microbial products). Chemical control options involve the use of pesticides and chemicals (e.g. glyphosate, diquat), or the use of flocculants and nutrient inactivation products that are used to reduce nutrient loading, thereby decreasing algal growth. Physical control options involve removing vegetation or algal biomass (e.g. mechanical or manual harvesting), or setting up barriers to their growth (e.g. shading, bottom lining, sediment capping).
Preventative management options are usually the most cost effective, and these are also briefly described (Section 6.0). For example, the use of hygiene or quarantine protocols can reduce weed introductions or spread. Catchment- based practices to reduce sediment and nutrient sources to stormwater are likely to assist in the avoidance of algal and possibly aquatic plant problems. Nutrient removal may be a co-benefit where harvesting of submerged weed biomass is undertaken in stormwater systems. It should also be considered that removal of substantial amounts of submerged vegetation may result in a sudden and difficult-to-reverse s witch to a turbid, phytoplankton dominated state. Another possible solution is the conversion of systems that experience aquatic vegetation issues, to systems that are less likely to experience issues.
The focus of this report is on systems that receive significant stormwater inputs, i.e. constructed bodies, including ponds, amenity lakes, wetlands, and highly-modified receiving bodies. However, some information will have application to other natural water bodies.

text: Review of best management practices for aquatic vegetation control in stormwater ponds, wetlands, and lakes Auckland Council (AC) is responsible for the development and operation of a stormwater network across the region to avert risks to citizens and the environment.
Within this stormwater network, aquatic vegetation (including plants, unicellular and filamentous algae) can have both a positive and negative role in stormwater management and water quality treatment. The situations where management is needed to control aquatic vegetation are not always clear, and an inability to identify effective, feasible and economical control options may constrain management initiatives. AC (Infrastructure and Technical Services, Stormwater) commissioned this technical report to provide information for decision- making on aquatic vegetation management with in stormwater systems that are likely to experience vegetation-related issues.
Information was collated from a comprehensive literature review, augmented by knowledge held by the authors. This review identified a wide range of management practices that could be potentially employed. It also demonstrated complexities and uncertainties relating to these options that makes the identification of a best management practice difficult. Hence, the focus of this report was to enable users to screen for potential options, and use reference material provided on each option to confirm the best practice to employ for each situation.
The report identifies factors to define whether there is an aquatic vegetation problem (Section 3.0), and emphasises the need for agreed management goals for control (e.g. reduction, mitigation, containment, eradication). Resources to screen which management option(s) to employ are provided (Section 4.0), relating to the target aquatic vegetation, likely applicability of options to the system being managed, indicative cost, and ease of implementation. Initial screening allows users to shortlist potential control options for further reference (Section 5.0).
Thirty-five control options are described (Section 5.0) in sufficient detail to consider applicability to individual sites and species. These options are grouped under categories of biological, chemical or physical control. Biological control options involve the use of organisms to predate, infect or control vegetation growth (e.g. classical biological control) or manipulate conditions to control algal growth (e.g. pest fish removal, microbial products). Chemical control options involve the use of pesticides and chemicals (e.g. glyphosate, diquat), or the use of flocculants and nutrient inactivation products that are used to reduce nutrient loading, thereby decreasing algal growth. Physical control options involve removing vegetation or algal biomass (e.g. mechanical or manual harvesting), or setting up barriers to their growth (e.g. shading, bottom lining, sediment capping).
Preventative management options are usually the most cost effective, and these are also briefly described (Section 6.0). For example, the use of hygiene or quarantine protocols can reduce weed introductions or spread. Catchment- based practices to reduce sediment and nutrient sources to stormwater are likely to assist in the avoidance of algal and possibly aquatic plant problems. Nutrient removal may be a co-benefit where harvesting of submerged weed biomass is undertaken in stormwater systems. It should also be considered that removal of substantial amounts of submerged vegetation may result in a sudden and difficult-to-reverse s witch to a turbid, phytoplankton dominated state. Another possible solution is the conversion of systems that experience aquatic vegetation issues, to systems that are less likely to experience issues.
The focus of this report is on systems that receive significant stormwater inputs, i.e. constructed bodies, including ponds, amenity lakes, wetlands, and highly-modified receiving bodies. However, some information will have application to other natural water bodies.

year: 2013

title: Community understanding and preparedness for tsunami risk in the eastern North Island, New Zealand

authors: Pishief, Katharine Sophie

subjects: tsunami

abstract: The Indian Ocean tsunami on 26 December 2004 made many New Zealanders more aware of the devastating affects that a tsunami can have on coastal communities, and highlighted the need for people living in the coastal zone to be prepared for natural hazard events. The east coast of New Zealand is at high risk from both local and distantly generated tsunami, and Poverty Bay and Hawke Bay have been identified among the most at risk areas from tsunamis in the country. Three surveys were conducted between January and November 2006 to assess community understanding of, and preparedness for tsunami risk in the eastern North Island, New Zealand. These surveys were a camping ground visitor survey; a tourism sector preparedness survey; and the 2006 National Coastal Survey.
Findings of all three surveys show that the general public does not appear to have sufficient knowledge of tsunami risk in their area. Also, there does not appear to be adequate information on tsunamis available to the public. Understanding of official tsunami warnings was high amongst residents surveyed in the 2006 National Coastal Survey. However, it was low amongst visitors surveyed in the camping grounds, with the majority of camping ground survey respondents indicating that they do not know what makes up the New Zealand public notification system. It is encouraging to find that overall the public are aware of the correct actions to take in the event of a tsunami warning being issued.
Staff in hotels/motels in the Napier area were not well prepared for managing natural hazard events, with the majority of respondents having no training for dealing with emergencies, and none of those who had received training had received training for tsunami hazards.
It is recommended that steps be taken to better educate and prepare the public and tourism managers in eastern North Island communities. This will require not only public education but a range of activities that engage, empower and motivate at-risk communities to respond effectively and appropriately to tsunami warnings.

text: Community understanding and preparedness for tsunami risk in the eastern North Island, New Zealand The Indian Ocean tsunami on 26 December 2004 made many New Zealanders more aware of the devastating affects that a tsunami can have on coastal communities, and highlighted the need for people living in the coastal zone to be prepared for natural hazard events. The east coast of New Zealand is at high risk from both local and distantly generated tsunami, and Poverty Bay and Hawke Bay have been identified among the most at risk areas from tsunamis in the country. Three surveys were conducted between January and November 2006 to assess community understanding of, and preparedness for tsunami risk in the eastern North Island, New Zealand. These surveys were a camping ground visitor survey; a tourism sector preparedness survey; and the 2006 National Coastal Survey.
Findings of all three surveys show that the general public does not appear to have sufficient knowledge of tsunami risk in their area. Also, there does not appear to be adequate information on tsunamis available to the public. Understanding of official tsunami warnings was high amongst residents surveyed in the 2006 National Coastal Survey. However, it was low amongst visitors surveyed in the camping grounds, with the majority of camping ground survey respondents indicating that they do not know what makes up the New Zealand public notification system. It is encouraging to find that overall the public are aware of the correct actions to take in the event of a tsunami warning being issued.
Staff in hotels/motels in the Napier area were not well prepared for managing natural hazard events, with the majority of respondents having no training for dealing with emergencies, and none of those who had received training had received training for tsunami hazards.
It is recommended that steps be taken to better educate and prepare the public and tourism managers in eastern North Island communities. This will require not only public education but a range of activities that engage, empower and motivate at-risk communities to respond effectively and appropriately to tsunami warnings.

year: 2007

title: Ideology is theft: Thoughts on the legitimacy of a Maori psychology

authors: Tamatea, Armon J.

subjects: Maori

abstract: ‘War, in fact, can be seen as a process of achieving equilibrium among unequal technologies’ (McLuhan, 1964) 
We are at war. As Western science and its accompanying technology expands the frontiers of knowledge at an ever-increasing rate, ‘indigenous’ perspectives of knowledge are exiled into the borderlands of special interest groups and localized research programmes. Mainstream scientific thought lays claim to objective interpretations of experience at the expense of alternative realities offered by emerging theories of knowledge. Furthermore, as localized worldviews (i.e., those derived from ancestral knowledge bases and pre-industrial or non-scientific premises) challenge existing paradigms, the inevitable interactions threaten to undermine the fidelity of this knowledge. One such arena where this ideological conflict is apparent is the growing field of Maori psychology.

text: Ideology is theft: Thoughts on the legitimacy of a Maori psychology ‘War, in fact, can be seen as a process of achieving equilibrium among unequal technologies’ (McLuhan, 1964) 
We are at war. As Western science and its accompanying technology expands the frontiers of knowledge at an ever-increasing rate, ‘indigenous’ perspectives of knowledge are exiled into the borderlands of special interest groups and localized research programmes. Mainstream scientific thought lays claim to objective interpretations of experience at the expense of alternative realities offered by emerging theories of knowledge. Furthermore, as localized worldviews (i.e., those derived from ancestral knowledge bases and pre-industrial or non-scientific premises) challenge existing paradigms, the inevitable interactions threaten to undermine the fidelity of this knowledge. One such arena where this ideological conflict is apparent is the growing field of Maori psychology.

year: 2008