In this study, a state‐of‐the‐art approach in modelling fish habitats, using high‐resolution topographical data, obtained from unmanned aerial vehicle, was applied. Habitat Suitability Indices are used to predict how changes in discharge affect instream fish habitats. Habitat Suitability Indices regarding depth and velocity for two size classes (small sized fish 5–15 cm total length and large sized >15 cm total length) of Salmo pelagonicus and Barbus balcanicus were used, in combination with a two‐dimensional hydraulic‐hydrodynamic model, for the estimation of the weighted usable area (WUA) in a mountainous stream. Computational mesh and/or digital terrain model (DTM) resolution selection may influence the accuracy of WUA results, especially in boulder and cobble‐bed streams with complex habitat structures. The aim of the study is to examine the sensitivity of various hydraulic‐hydrodynamic modelling geometry configurations on WUA at ungauged or poorly gauged streams. Comparisons of three different geometry configurations: (1) identical computational mesh and DTM resolution (SensComb); (2) finest computational mesh resolution combined with different DTM resolutions (SensDTM); (3) finest DTM resolution combined with different computational mesh resolutions, as part of two‐dimensional hydrodynamic modelling, were applied to test the differences in WUA (SensMesh). WUA maps were generated for both fish species and class sizes for each modelling geometry configuration and compared with each other for assessing the sensitivity of the two‐input data (computational mesh and DTM). Results provided by both indices and their spatial distribution indicated the optimal DTM and computational mesh resolution as well as the sensitivity of a specific hydraulic‐habitat model on them.

中文翻译：

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栖息地水力模型输出对DTM的敏感性和计算网格分辨率

在这项研究中，采用了从无人飞行器获得的高分辨率地形数据对鱼类栖息地进行建模的最新方法。生境适应性指数用于预测排放量变化如何影响河内鱼类生境。关于深度和速度为两种尺寸的类（小尺寸的鱼总5-15厘米的长度尺寸和大尺寸>15厘米总长度）生境适宜指数鲑pelagonicus和鲤balcanicus与二维水力流体动力学模型结合起来，用于估算山区河流的加权可用面积（WUA）。计算网格和/或数字地形模型（DTM）的分辨率选择可能会影响WUA结果的准确性，尤其是在具有复杂栖息地结构的巨石和卵石床流中。这项研究的目的是研究在无流量或流量不佳的河流上，各种水力流体动力学建模几何配置对WUA的敏感性。三种不同几何配置的比较：（1）相同的计算网格和DTM分辨率（SensComb）；（2）结合不同DTM分辨率（SensDTM）的最佳计算网格分辨率；（3）最好的DTM分辨率结合不同的计算网格分辨率，作为二维流体动力学建模的一部分，被应用于测试WUA（SensMesh）中的差异。为每种建模几何配置生成了鱼类种类和类别大小的WUA地图，并相互比较以评估两次输入数据（计算网格和DTM）的敏感性。指数及其空间分布所提供的结果表明了最佳的DTM和计算网格分辨率，以及特定液压栖息地模型对它们的敏感性。