The Murray-Darling Freshwater Research Centre, PO Box 991, Wodonga, VIC, 3689, Australia.
Environ Manage. 2013 Oct;52(4):837-50. doi: 10.1007/s00267-013-0130-9. Epub 2013 Aug 3.
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.
当大量有机物质被浸滤到水体中（例如，在泛滥平原淹没期间），并且这种碳的快速代谢使水柱中的氧气耗尽时，就会发生缺氧黑水事件，这对水生环境通常会产生灾难性影响。河流调节可能增加了低地河流系统中缺氧黑水事件的频率和严重程度，需要进行管理干预，以减轻这些事件对水生生物群的影响。我们研究了在澳大利亚墨累-达令盆地发生的大规模缺氧黑水事件中使用的一系列缓解干预措施的有效性，这些措施可能适用于其他面临缺氧黑水风险的环境。缓解缺氧的策略包括：输送稀释水流；通过增加水面紊流来提高物理复氧率；将黑水引入浅滩旁的储存库。我们表明，稀释水输送的影响取决于相对体积和水质，可以使用简单的模型进行预测。在稀释水入口处，局部充氧羽流也可以作为避难所。物理复氧策略通常只会导致溶解氧的少量增加，但可能有助于保护局部避难所。在大型浅湖系统中，稀释和自然复氧过程足以补偿缺氧流入，并且可以将旁道湖中处理的水作为稀释水流返回河道。我们提供了一组预测模型（见电子补充材料），用于估算干预活动的复氧潜力，并为未来缺氧黑水事件的自适应管理提供框架。
