School of Earth and Environmental Sciences, University of Queensland, St Lucia, QLD, 4072, Australia.
School of Earth and Environmental Sciences, University of Queensland, St Lucia, QLD, 4072, Australia.
J Environ Manage. 2022 Jan 15;302(Pt A):113991. doi: 10.1016/j.jenvman.2021.113991. Epub 2021 Oct 27.
Streamflow patterns are closely linked with the quality of stream water, but they are often dealt separately. Due to this, the effects of change in streamflow patterns resulting from river regulation and flow diversion on stream water quality remain under-investigated. This study models change in water quality indicators including pollutants (total suspended solids and turbidity), nutrients (total nitrogen and phosphorus), dissolved oxygen, nitrogen (kjeldahl), pH, and salinity caused by the change in streamflow patterns under different scenarios of river regulation, flow diversion, and rainfall. The generalized additive model was used and the Goulburn-Broken catchment, Australia was chosen as the case study. It was found that concentrations of pollutants and nutrients increased by 38% while dissolved oxygen and nitrogen (kjeldahl) decreased by 35% during the period 1990-2018. These changes were associated with an average increase of 20% in low and medium flows, an average decline of 22% in high and overbank flows and a 15% decline in rainfall. Under the scenario of climate change, river regulation and flow diversion, the overbank flow patterns would mimic the effects of low and medium flows on the water quality indicators that would raise the concentration of pollutants, nutrients, and salinity by 19%. Restoration of high flows would decrease these concentrations by 28% relative to current concentrations, however, it would also reduce dissolved oxygen, nitrogen (kjeldahl), and pH. Effects of streamflow patterns on water quality have implications for environmental flow management, thus, this study recommends critical adjustments in low, medium, and high flows for improving water quality.
水流模式与水质密切相关，但通常是分开处理的。由于这一点，河流调节和分流导致的水流模式变化对水质的影响仍未得到充分研究。本研究模拟了在不同的河流调节、分流和降雨情景下，水流模式变化对水质指标（包括污染物（总悬浮物和浊度）、营养物（总氮和总磷）、溶解氧、氮（凯氏）、pH 值和盐度）的影响。采用广义加性模型，以澳大利亚古尔本-布鲁克流域为案例研究。结果发现，1990-2018 年期间，污染物和营养物浓度增加了 38%，而溶解氧和氮（凯氏）减少了 35%。这些变化与低中流量平均增加 20%、高流量和漫滩流量平均减少 22%以及降雨量减少 15%有关。在气候变化、河流调节和分流的情景下，漫滩流量模式将模拟低中流量对水质指标的影响，使污染物、营养物和盐度的浓度增加 19%。恢复高流量将使这些浓度相对于当前浓度降低 28%，但也会降低溶解氧、氮（凯氏）和 pH 值。水流模式对水质的影响对环境水流管理具有重要意义，因此，本研究建议对低、中、高流量进行关键调整，以改善水质。
