Murphy Darragh, Weatherill John, Henriques Rossana, Quishi Xie, Harrison Simon
School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.
School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland; Environmental Research Institute, Ellen Hutchins Building, University College Cork, Cork, Ireland; iCRAG Science Foundation Ireland Research Centre in Applied Geosciences, University College Dublin, Ireland.
J Environ Manage. 2025 Jan;373:123858. doi: 10.1016/j.jenvman.2024.123858. Epub 2024 Dec 31.
Nature-based Solutions (NbS) are widely advocated to have multiple benefits, including in flood risk reduction, water quality improvement and ecosystem health. There are, however, few empirical studies quantifying such multi-functionality. Given the ongoing pressures of flooding and poor water quality within Europe, there is an urgent need for empirical evidence to assess the potential for NbS features to address these issues. We present the first empirical results on the impacts of a nature-based flood detention basin on peak flow attenuation, water quality and pasture health. The detention basin comprised a 1.5m high soil bund constructed within a field bordering a first order tributary on a farm in the south of Ireland. Over two years, peak flows were diverted from the stream channel to the detention basin via a constructed sluice during the rising limb of high discharge. Detained waters were returned slowly to the channel via drainage pipes. During this time hydrological and quality data were collected from upstream, downstream and within the detention basin during peak flow events and pasture sward growth and health within the detention basin was assessed. These data revealed marked peak flow attenuation by < 38%, except under conditions of prolonged rainfall. The detention basin sequestered suspended solids (Removal efficiency RE 5.35%; p < 0.05) and nitrate (RE 13.37%; p < 0.001), but was a source of soluble reactive (RE -95%; p < 0.001) and particulate phosphorus (RE -83%; p < 0.001). There was no statistically significant reduction in pasture biomass, but higher Chlorophyll a/b ratio of inundated plants indicated reduced photosynthetic efficiency (30.85%; p < 0.001). Whilst capable of reducing peak flows, the mixed results on water quality and pasture health show that the operation of NbS features is complex, and that multi-functionality is not an inherent facet of NbS.
基于自然的解决方案（NbS）被广泛倡导具有多种效益，包括降低洪水风险、改善水质和维护生态系统健康。然而，很少有实证研究对这种多功能性进行量化。鉴于欧洲持续面临洪水和水质不佳的压力，迫切需要实证证据来评估基于自然的解决方案特征应对这些问题的潜力。我们展示了关于一个基于自然的滞洪池对洪峰流量衰减、水质和牧场健康影响的首批实证结果。该滞洪池由一个1.5米高的土堤构成，建在爱尔兰南部一个农场与一级支流相邻的田地里。在两年时间里，在高流量上升阶段，通过一个建造的水闸将洪峰流量从河道引到滞洪池。滞留的水通过排水管道缓慢回流到河道。在此期间，在洪峰流量事件期间，从上游、下游和滞洪池内收集水文和水质数据，并评估滞洪池内牧场草皮的生长和健康状况。这些数据显示，除了在长时间降雨的情况下，洪峰流量显著衰减了<38%。滞洪池截留了悬浮固体（去除效率RE为5.35%；p<0.05）和硝酸盐（RE为13.37%；p<0.001），但却是可溶性活性磷（RE为-95%；p<0.001）和颗粒磷（RE为-83%；p<0.001）的来源。牧场生物量没有统计学上的显著减少，但被淹没植物较高的叶绿素a/b比值表明光合效率降低（30.85%；p<0.001）。虽然能够降低洪峰流量，但水质和牧场健康方面的混合结果表明，基于自然的解决方案特征的运行是复杂的，而且多功能性并非基于自然的解决方案的固有特性。
