Kathleen Bowmer

Dilution and decay of aquatic herbicides in flowing channels

Abstract The behaviour of herbicides injected into flowing irrigation channels for aquatic weed control is analysed. Solutions to the one-dimensional convective-diffusion equation are given for instantaneous and step-function injections of a decaying tracer. The basic solutions are used to derive methods for determining the degradation rate from field experiments, and the total exposure to the herbicide as the water flows over the weeds. It is shown that some significant aspects of herbicide behaviour are unaffected by dispersion, and depend only on the degradation rate constant and the travel time of the material. Observations from trials in irrigation channels in the U.S.A. and Australia with the herbicide acrolein are analysed. The herbicide application rates and computed exposures vary greatly. Degradation rate constants are more nearly equal.

Dam reoperation in an era of climate change

Climate change is predicted to affect the future supply and demand for water resources. Current water-management practices may not adequately cope with the impacts of climate change on the reliability of water supply, flood risk, health, agriculture, energy generation and aquatic ecosystems. Water managers can adapt to climate variability by structural change, such as increasing the size or number of dams, building desalination plants and transferring water between catchments; however, a broader set of alternatives with multiple beneficial outcomes for society and the environment should be explored. We discuss how modifying dam operations, ‘dam reoperation’, can assist with adaptation to climate change and help restore ecosystems. The main operating purpose of a dam (e.g. flood management, hydropower or water supply) will influence dam reoperation strategies. Reoperation may require integration across sectors or involve multiple dams, enhancing benefits such as water supply or hydropower while simultaneously achieving ecosystem restoration. We provide examples of lessons learned during extreme scenarios (e.g. floods and droughts), where operational flexibility has been demonstrated. We contrast structural climate-change adaptation strategies (e.g. building new dams) and their resulting detrimental environmental outcomes with dam reoperation, which can maximise benefits for ecosystems and society.

Assessing Government Intentions for Australian Water Reform Using a Social Justice Framework

Concerns about justice are increasing as Australian governments continue to implement water reform, often facing hostility from stakeholders with conflicting interests. This article presents a social justice framework that can be used to analyze water reform from a justice perspective. The framework is a compilation of existing justice theories taken from the social psychology literature and is based on the components of distributive, procedural, and interactive justice. We applied the framework in a content analysis of eight key policy documents on water reform. Results show that Australian governments intend that justice be achieved across the distributive and procedural components, with distribution scoring highest and procedural concerns being most numerous. Justice in water reform is predominantly constructed as distribution according to need, with transparent, consistent, and accurate decision making as a second priority. The analysis shows that the framework is a useful tool for evaluating and developing policy using a justice perspective.

Water resources in Australia: deliberation on options for protection and management

Policy for the protection of water resources requires a more holistic and integrated approach to transcend disciplinary boundaries, to overcome fragmented governance, and to create ownership of solutions through collaborative planning. In this Australian case study I summarise critical water quality characteristics (salinity, acidity, nitrogen, phosphorus, carbon, turbidity, micropollutants and pathogenic organisms) and management options in the context of the needs of stakeholders. Stakeholders are: dryland and irrigation farmers; urban and industrial users; and the aquatic environment. Management options are: changes in land use; interception methods (such as filtration by riparian vegetation, use of artificial wetlands and evaporation ponds); reliance on technological water treatment methods; reuse; and trading. Clearly, the protection of water resources is a ‘wicked’ problem. Critical decision-making requires greater emphasis on inclusive agricultural, ecocentric and technological thinking that includes: an understanding of the water cycle; consideration of interaction between stressors and use of systems approaches; better methods to value the aquatic environment; assessment of land use impacts on water resources; use of incentives to change behaviour; and community involvement to create sustainable futures through transformation and resilience practice. To their credit, Australians are working together to explore solutions and support is available. Some examples are provided.

How the social construction of the environment affects people's reactions to water policy

Abstract Over the past 20 years, water reform has moved to clarify water rights and responsibilities among users, separated water and land management, and introduced markets. Most recently, water policy has clearly recognised the need for environmental allocations to ensure sustainability. These reforms, especially the last, have created conflicts between stakeholder groups. While these conflicts have been couched on many occasions as irrigation versus conservation, this article shows that the basis of these arguments lies in tacit differences in the constructed meaning attached to the environment by different stakeholders. It explores the differences between how government managers, scientists and non-government stakeholders, such as irrigators, foresters, croppers and graziers, as well as Aboriginal elders, view the environment. Our study is based on interviews with government managers responsible for water management and rural non-government stakeholders in two case study sites in the Murray-Darling Basin, where water reform has caused vigorous debates. The findings show that scientists and government managers tend to see the environment as the passive recipient of human impacts, problems best addressed by objective science. In contrast, landholders see themselves as active agents within the environment, and place much more emphasis on personal experience and local knowledge. These worldviews influence peoples reactions to water policy but are rarely explicitly discussed or acknowledged. This results in unnecessary conflict in public debate. Understanding the government and landholder perspectives is essential as a foundation for effective collaborative planning.

Investigating over-allocation of water using risk analysis: a case study in Tasmania, Australia

The determination of a sustainable level of extraction is a challenge to water reform and planning, especially where information on environmental assets is sparse, and where future flow regime is threatened by irrigation and climate change. Hamstead (2009) considered a catchment to be over-allocated and/or overused if projected changes in freshwater flow posed a medium or higher level of risk to key ecological assets. The present paper investigates Hamstead’s (2009) two-step risk analysis process by using the Coal Pitt Water Catchment in Tasmania, Australia, where the Ramsar-listed Pittwater–Orielton Lagoon was identified as the key ecological asset. Although Hamstead’s (2009) approach revealed over-allocation and/or overuse, several limitations emerged. In particular, setting the current condition as the baseline ecosystem condition, rather than that at the time of Ramsar listing, permits over-allocation and/or overuse to continue and contravenes international, national and state obligations. Projections could be improved by inclusion of a river condition index and hydrological indicators such as proportion of total natural flow retained, frequency of estuary flushing, and percentage of median annual flow impounded. Available ecological information and projected hydrological change should be included in determining the threat to environmental assets because statutory obligations require strategies to manage processes that threaten species and communities.

Law and governance of water resources: the challenge of sustainability

Douglas Fisher is the author of numerous texts on law relating to environment, natural resources and water. This latest book continues Fisher’s meticulous textual and linguistic analysis of legal doctrines and instruments in relation to water resources. Thematic organisation of material is Fisher’s forte and the structure of this book shows the thought put into achieving a rational presentation of the large amount of material on the subject. The book has seven parts, starting with the challenge of sustainable water resources governance, the formal structure of governance, the normative structure of international arrangements, the normative structure of national arrangements, evolving international arrangements, evolving national arrangements, and lastly, innovations for achieving sustainability. Readers will find the material relatively easy to locate because of this thematic framing and the detailed contents pages. In an effort to make the material accessible, each part also begins with a two page overview of its subject matter. Parts I and II which relate to the challenge of sustainability and the formal structures of water governance present material covered elsewhere, both in Fisher’s own work and in others’. What is useful is the brief presentation of models of governance, including in New Zealand through the Resource Management Act 1991, in the European Union, and through the Draft International Covenant on Environment and Development. Because this is a textual analysis, considerable attention is given to exploration of concepts such as ‘balancing norm’ (p. 32) and ‘interstitial normativity’ (p. 33). Normative structures are covered in Parts III and IV. In chapters relating to the international sphere, Fisher continues to explore what is meant by interstitial normativity the relationship between legal and paralegal rules and in language familiar to legal theoreticians explores norms and the Grundnorm underlying the management of international watercourses. With regard to the latter, Fisher postulates that the fundamental norm in international law appears to be the equitable and reasonable utilisation of water in conjunction with protection of the environment and prevention of pollution. In the same manner, Parts V and VI deal with evolving international and national arrangements. The sweep of material attempts to build a bridge across international law and domestic law, and this is no mean feat. Although one can see why material covering international law is separated between the normative structures (in Part III) and the chapters in Parts V, which deal with concepts such as the human right to water, conflict and cooperation, I suggest that the thematic Australasian Journal of Environmental Management Vol. 18, No. 1, March 2011, 61 68