John Conallin

Options for Managing Hypoxic Blackwater in River Systems: Case Studies and Framework

Hypoxic blackwater events occur when large amounts of organic material are leached into a water body (e.g., during floodplain inundation) and rapid metabolism of this carbon depletes oxygen from the water column, often with catastrophic effects on the aquatic environment. River regulation may have increased the frequency and severity of hypoxic blackwater events in lowland river systems, necessitating management intervention to mitigate the impacts of these events on aquatic biota. We examine the effectiveness of a range of mitigation interventions that have been used during large-scale hypoxic blackwater events in the Murray–Darling Basin, Australia and that may be applicable in other environments at risk from hypoxic blackwater. Strategies for hypoxia mitigation include: delivery of dilution flows; enhancement of physical re-aeration rates by increasing surface turbulence; and diversion of blackwater into shallow off-channel storages. We show that the impact of dilution water delivery is determined by relative volumes and water quality and can be predicted using simple models. At the dilution water inflow point, localized oxygenated plumes may also act as refuges. Physical re-aeration strategies generally result in only a small increase in dissolved oxygen but may be beneficial for local refuge protection. Dilution and natural re-aeration processes in large, shallow lake systems can be sufficient to compensate for hypoxic inflows and water processed in off-channel lakes may be able to be returned to the river channel as dilution flows. We provide a set of predictive models (as electronic supplementary material) for estimation of the re-aeration potential of intervention activities and a framework to guide the adaptive management of future hypoxic blackwater events.

Adaptive Management of Environmental Flows

Adaptive management enables managers to work with complexity and uncertainty, and to respond to changing biophysical and social conditions. Amid considerable uncertainty over the benefits of environmental flows, governments are embracing adaptive management as a means to inform decision making. This Special Issue of Environmental Management presents examples of adaptive management of environmental flows and addresses claims that there are few examples of its successful implementation. It arose from a session at the 11th International Symposium on Ecohydraulics held in Australia, and is consequently dominated by papers from Australia. We classified the papers according to the involvement of researchers, managers and the local community in adaptive management. Five papers report on approaches developed by researchers, and one paper on a community-led program; these case studies currently have little impact on decision making. Six papers provide examples involving water managers and researchers, and two papers provide examples involving water managers and the local community. There are no papers where researchers, managers and local communities all contribute equally to adaptive management. Successful adaptive management of environmental flows occurs more often than is perceived. The final paper explores why successes are rarely reported, suggesting a lack of emphasis on reflection on management practices. One major challenge is to increase the documentation of successful adaptive management, so that benefits of learning extend beyond the project where it takes place. Finally, moving towards greater involvement of all stakeholders is critical if we are to realize the benefits of adaptive management for improving outcomes from environmental flows.

Stakeholder Engagement in Environmental Water Management

This chapter introduces the concept of stakeholder engagement within water resource management with a focus on environmental water programs. It explains why stakeholder engagement is critical, and the theoretical basis for effective stakeholder engagement. Moving from theory into practice it advocates for principle-based engagement through 10 key principles, and describes 5 key steps for successful implementation. Three short case studies demonstrate some of the principles of stakeholder engagement and the varying challenges associated with stakeholder engagement in different situations. Further examples of principles, and steps, from around the world are also highlighted. It must be recognized that stakeholder engagement is individual to the situation, dynamic, and one of the most challenging components of any management program, hence highlighting how critical it is to include and prioritize both from a funding and human resource side. Even though resourcing stakeholder engagement usually adds short-term complexity and cost, in general effective stakeholder engagement reduces transaction costs and leads to more successful long-term outcomes.

Adaptive Management of Environmental Flows: Using Irrigation Infrastructure to Deliver Environmental Benefits During a Large Hypoxic Blackwater Event in the Southern Murray–Darling Basin, Australia

Widespread flooding in south-eastern Australia in 2010 resulted in a hypoxic (low dissolved oxygen, DO) blackwater (high dissolved carbon) event affecting 1800 kilometres of the Murray–Darling Basin. There was concern that prolonged low DO would result in death of aquatic biota. Australian federal and state governments and local stakeholders collaborated to create refuge areas by releasing water with higher DO from irrigation canals via regulating structures (known as ‘irrigation canal escapes’) into rivers in the Edward–Wakool system. To determine if these environmental flows resulted in good environmental outcomes in rivers affected by hypoxic blackwater, we evaluated (1) water chemistry data collected before, during and after the intervention, from river reaches upstream and downstream of the three irrigation canal escapes used to deliver the environmental flows, (2) fish assemblage surveys undertaken before and after the blackwater event, and (3) reports of fish kills from fisheries officers and local citizens. The environmental flows had positive outcomes; mean DO increased by 1–2 mg L−1 for at least 40 km downstream of two escapes, and there were fewer days when DO was below the sub-lethal threshold of 4 mg L−1 and the lethal threshold of 2 mg L−1 at which fish are known to become stressed or die, respectively. There were no fish deaths in reaches receiving environmental flows, whereas fish deaths were reported elsewhere throughout the system. This study demonstrates that adaptive management of environmental flows can occur through collaboration and the timely provision of monitoring results and local knowledge.

Stakeholder Participation in Freshwater Monitoring and Evaluation Programs: Applying Thresholds of Potential Concern within Environmental Flows

The complex nature of freshwater systems provides challenges for incorporating evidence-based techniques into management. This paper investigates the potential of participatory evidence-based techniques to involve local stakeholders and make decisions based on different “knowledge” sources within adaptive management programs. It focuses on the application of thresholds of potential concern (TPC) within strategic adaptive management (SAM) for facilitating inclusive decision-making. The study is based on the case of the Edward-Wakool (E-W) “Fish and Flows” SAM project in the Murray–Darling River Basin, Australia. We demonstrate the application of TPCs for improving collaborative decision-making within the E-W, associated with environmental watering requirements, and other natural resource management programs such as fish stocking. The development of TPCs in the E-W fish and flows SAM project helped improve stakeholder involvement and understanding of the system, and also the effectiveness of the implemented management interventions. TPCs ultimately helped inform environmental flow management activities. The TPC process complemented monitoring that was already occurring in the system and provided a mechanism for linking formal and informal knowledge to form explicit and measurable endpoints from objectives. The TPC process faced challenges due to the perceived reduction in scientific rigor within initial TPC development and use. However, TPCs must remain tangible to managers and other stakeholders, in order to aid in the implementation of adaptive management. Once accepted by stakeholders, over time TPCs should be reviewed and refined in order to increase their scientific rigor, as new information is generated.

Implementation of Environmental Flows for Intermittent River Systems: Adaptive Management and Stakeholder Participation Facilitate Implementation

Anthropogenic pressure on freshwater ecosystems is increasing, and often leading to unacceptable social-ecological outcomes. This is even more prevalent in intermittent river systems where many are already heavily modified, or human encroachment is increasing. Although adaptive management approaches have the potential to aid in providing the framework to consider the complexities of intermittent river systems and improve utility within the management of these systems, success has been variable. This paper looks at the application of an adaptive management pilot project within an environmental flows program in an intermittent stream (Tuppal Creek) in the Murray Darling Basin, Australia. The program focused on stakeholder involvement, participatory decision-making, and simple monitoring as the basis of an adaptive management approach. The approach found that by building trust and ownership through concentrating on inclusiveness and transparency, partnerships between government agencies and landholders were developed. This facilitated a willingness to accept greater risks and unintended consequences allowing implementation to occur.

Moving Forward: The Implementation Challenge for Environmental Water Management

Although there has been significant progress in environmental water management across the globe, a number of challenges remain in the establishment and delivery of environmental water regimes on the ground—the implementation challenge. This final chapter focuses on the directions to achieve successful implementation of environmental water policies and practice into the future, and is organized around six key questions: (1) How much water do rivers need? (2) How do we increase the number of rivers where environmental water is provided? (3) How can we embed environmental water management as a core element of water resource planning? (4) How can knowledge and experience be transferred and scaled more easily? (5) How can we enhance the legitimacy of environmental water programs? (6) How can we support the inclusion of adaptive management as standard practice? Many of these ongoing challenges are not technical in nature, but rather related to concepts of engagement, partnership, legitimacy, sharing of knowledge, and enabling institutional policies and structures.

Using Strategic Adaptive Management to Facilitate Implementation of Environmental Flow Programs in Complex Social-Ecological Systems

Freshwater resource management is becoming increasingly complex as human pressure increases on available water resources, and as more participatory transparent decision-making frameworks are being advocated within water management. Complexity is further increased when environmental flow programs are integrated into existing water management programs. Adaptive management frameworks present an obvious choice for integration and implementation of environmental flows, but have so far failed to become the dominant framework. The research presented here highlights the ability of a strategic adaptive management (SAM) approach within an environmental flow program in the Murray Darling Basin of Australia to facilitate planning and implementation of environmental flows. The SAM approach did show that adaptive management can deal with the complexities of designing and implementing environmental flows within complex social-ecological systems, but can have limitations in the long-term. The approach highlighted the importance of social processes within adaptive management, emphasizing that a focus on inclusiveness, commitment, and transparency aimed at building understanding, trust, and ownership are key processes for implementation. In this specific case study, successful implementation was achieved through structured co-design of initial programs and participatory decision-making throughout. However, the SAM approach also showed that adaptive management is vulnerable to challenges in the long-term when resources and expertize change.

Managing native fish communities during a long‐term drought

Department of Primary Industries, Narrandera Fisheries Centre, PO Box 182, Narrandera, New South Wales 2700, Australia Department of Primary Industries, Murray Local Land Services, 315 Victoria Street, Deniliquin, New South Wales 2710, Australia Water Science and Engineering Department UNESCO‐IHE, Westvest 7, 2611AX, Delft, Netherlands 4 Institute for Land, Water and Society, Charles Sturt University, Albury, New South Wales, Australia Correspondence Lee J. Baumgartner, Institute for Land, Water and Society, Charles Sturt University, Albury, New South Wales, Australia. Email: lbaumgartner@csu.edu.au