Department of Civil, Environmental and Mechanical Engineering, via Mesiano 77, 38123 Trento, Italy.
Free University of Bolzano, Faculty of Science and Technology, Universitätsplatz 5, 39100 Bolzano, Italy.
Sci Total Environ. 2017 Jan 1;575:219-230. doi: 10.1016/j.scitotenv.2016.10.046. Epub 2016 Oct 12.
One way to study ecological implications induced by hydropeaking represents the coupling of hydrodynamic models with habitat suitability models, in which hydrodynamic parameters are typically used to describe the physical habitat of indicator species. This article discusses the differences in habitat suitability assessment between 2D and 3D CFD modelling as input for the habitat simulation tool CASiMiR. In the first part of the article, the accuracy of the hydraulic model is evaluated by comparing the model results with laboratory (model of a laboratory channel with erodible bed) and field measurements (Valsura River, Bolzano, Italy). In the second part, the habitat suitability for the Valsura River case study (affected by hydropeaking), is analyzed comparing different approaches for the reconstruction of the velocity field (depth-averaged velocities from 2D modelling, bottom velocity field reconstruction with log-law approach from 2D modelling and bottom velocity field from 3D modelling). The results show that the habitat suitability index (HSI) using 2D or 3D hydrodynamic models can be significantly different. These differences can be ascribed to a higher capability to depict the features of the flow field with highly variable and heterogeneous boundary conditions and to the possibility to simulate the near bed hydrodynamic parameters, which are relevant for certain target species. In particular, the HSI-values using 3D hydraulics lead to larger areas of highly suitable habitats compared to 2D simulations. Moreover, considering the entire flow range of hydropeaking events, the habitat simulations with bottom flow velocities from 3D modelling provide suitable habitats over the entire flow range representing the availability of stable suitable habitats, while the habitat availability of 2D modelled flow velocity is continuously decreasing with increasing flow rates.
一种研究由调峰引起的生态影响的方法是将水动力模型与栖息地适宜性模型耦合，其中水动力参数通常用于描述指示物种的物理栖息地。本文讨论了 2D 和 3D CFD 建模作为栖息地模拟工具 CASiMiR 的输入在栖息地适宜性评估方面的差异。在文章的第一部分，通过将模型结果与实验室（具有可侵蚀床的实验室渠道模型）和现场测量（意大利博尔扎诺的瓦尔苏拉河）进行比较，评估了水力模型的准确性。在第二部分，通过比较不同方法重建流速场（二维建模的水深平均流速、二维建模的对数律方法重建的底部流速场和三维建模的底部流速场），分析了瓦尔苏拉河案例研究（受调峰影响）的栖息地适宜性。结果表明，使用二维或三维水动力模型的栖息地适宜指数（HSI）可能有很大差异。这些差异可以归因于更高的能力来描绘具有高度变化和不均匀边界条件的流场特征，以及模拟对某些目标物种相关的近底水动力参数的能力。特别是，与二维模拟相比，使用三维水力学的 HSI 值导致高度适宜栖息地的面积更大。此外，考虑到调峰事件的整个流量范围，使用三维底部流速进行的栖息地模拟可在整个流量范围内提供适宜的栖息地，代表稳定适宜栖息地的可用性，而二维模拟的流速的栖息地可用性随着流量的增加而不断降低。
