Bainbridge Zoe, Olley Jon, Wilkinson Scott, Bartley Rebecca, Lewis Stephen, Dougall Cameron, Khan Sana, Kuhnert Petra, Burton Joanne
Catchment to Reef Research Group, TropWATER, James Cook University, Townsville, Australia.
Australian Rivers Institute, Griffith University, Brisbane, Australia.
Sci Total Environ. 2023 Sep 20;892:164731. doi: 10.1016/j.scitotenv.2023.164731. Epub 2023 Jun 7.
Excess fine sediment delivery is a major contributor to the declining health of the Great Barrier Reef and identifying the dominant source areas of fine sediment has been critical to prioritising erosion remediation programs. The Bowen River catchment within the Burdekin Basin has been recognised as a major contributor and hence received considerable research investment over the last two decades. This study adopts a novel approach to integrate three independently derived sediment budgets produced from a catchment scale sediment budget model (Dynamic SedNet), targeted tributary water quality monitoring and geochemical sediment source tracing to refine and map the sediment source zones within the Bowen catchment. A four year study of water quality monitoring combined with modelled discharge estimates and geochemical source tracing both identified that the Little Bowen River and Rosella Creek were the largest sources of sediment in the Bowen River catchment. Both data sets contradicted initial synoptic sediment budget model predictions due to inadequate representation of hillslope and gully erosion. Recent improvements in model inputs have resulted in predictions that are consistent with the field data and are of finer resolution within the identified source areas. Priorities for further investigation of erosion processes are also revealed. Examining the benefits and limitations of each method indicates that these are complimentary methods which can effectively be used as multiple lines of evidence. An integrated dataset such as this provides a higher level of certainty in the prediction of fine sediment sources than a single line of evidence dataset or model. The use of high quality, integrated datasets to inform catchment management prioritisation will provide greater confidence for decision makers when investing in catchment management.
过量的细颗粒泥沙输送是大堡礁健康状况下降的主要原因之一，确定细颗粒泥沙的主要来源地对于确定侵蚀修复计划的优先级至关重要。伯德金盆地内的博文河流域被认为是主要贡献者，因此在过去二十年中获得了大量研究投资。本研究采用了一种新颖的方法，将由流域尺度泥沙收支模型（动态泥沙网络）、有针对性的支流水质监测和地球化学泥沙源追踪独立得出的三个泥沙收支整合起来，以完善和绘制博文河流域内的泥沙源区地图。一项为期四年的水质监测研究，结合模拟流量估算和地球化学源追踪，均表明小博文河和罗塞拉溪是博文河流域最大的泥沙来源。由于山坡和沟壑侵蚀的代表性不足，这两个数据集都与最初的概略泥沙收支模型预测相矛盾。模型输入的最新改进使得预测结果与实地数据一致，并且在确定的源区内具有更高的分辨率。还揭示了侵蚀过程进一步研究的重点。对每种方法的优缺点进行研究表明，这些方法是互补的，可以有效地用作多条证据。这样一个综合数据集在预测细颗粒泥沙来源方面比单一证据数据集或模型具有更高的确定性。使用高质量的综合数据集为流域管理优先级提供信息，将为决策者在投资流域管理时提供更大的信心。
