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This study suggests a stochastic Bayesian approach for calibrating and validating morphodynamic sediment transport models and for quantifying parametric uncertainties in order to alleviate limitations of conventional (manual, deterministic) calibration procedures. The applicability of our method is shown for a large‐scale (11.0 km) and time‐demanding (9.14 hr for the period 2002–2013) 2‐D morphodynamic sediment transport model of the Lower River Salzach and for three most sensitive input parameters (critical Shields parameter, grain roughness, and grain size distribution). Since Bayesian methods require a significant number of simulation runs, this work proposes to construct a surrogate model, here with the arbitrary polynomial chaos technique. The surrogate model is constructed from a limited set of runs (n =20) of the full complex sediment transport model. Then, Monte Carlo‐based techniques for Bayesian calibration are used with the surrogate model (105 realizations in 4 hr). The results demonstrate that following Bayesian principles and iterative Bayesian updating of the surrogate model (10 iterations) enables to identify the most probable ranges of the three calibration parameters. Model verification based on the maximum a posteriori parameter combination indicates that the surrogate model accurately replicates the morphodynamic behavior of the sediment transport model for both calibration (RMSE = 0.31 m) and validation (RMSE = 0.42 m). Furthermore, it is shown that the surrogate model is highly effective in lowering the total computational time for Bayesian calibration, validation, and uncertainty analysis. As a whole, this provides more realistic calibration and validation of morphodynamic sediment transport models with quantified uncertainty in less time compared to conventional calibration procedures.
Felix Beckers; Andrés Heredia; Markus Noack; Wolfgang Nowak; Silke Wieprecht; Sergey Oladyshkin. Bayesian Calibration and Validation of a Large‐Scale and Time‐Demanding Sediment Transport Model. Water Resources Research 2020, 56, 1 .
AMA StyleFelix Beckers, Andrés Heredia, Markus Noack, Wolfgang Nowak, Silke Wieprecht, Sergey Oladyshkin. Bayesian Calibration and Validation of a Large‐Scale and Time‐Demanding Sediment Transport Model. Water Resources Research. 2020; 56 (7):1.
Chicago/Turabian StyleFelix Beckers; Andrés Heredia; Markus Noack; Wolfgang Nowak; Silke Wieprecht; Sergey Oladyshkin. 2020. "Bayesian Calibration and Validation of a Large‐Scale and Time‐Demanding Sediment Transport Model." Water Resources Research 56, no. 7: 1.
To investigate the erosion stability of reservoir sediments, two measuring strategies were applied. Next to in situ measurements, sediment cores were extracted and analysed in the laboratory. At several sampling points at a reservoir in Germany, the in situ device was used to determine the critical bed shear stresses at the sediment surface. At the same time, sediment cores were withdrawn at each site to perform depth-orientated investigations in the hydraulic laboratory. The objective of this study is to investigate the remobilisation potential of the deposited fine sediments and to compare different methods to determine the erosion threshold. Next to critical shear stresses and erosion rates, additional sedimentary and biological parameters were examined such as bulk densities, particle size distributions, TOC-contents and chlorophylla concentrations. The results show generally a very low erosion stability, especially at the sediment surface and in the upper sediment layers. Deeper sediment layers are characterised by consolidation effects and show a higher erosion resistance. High clay contents result in increased stability while high sand contents show a high remobilisation potential. No significant relation to the parameters TOC-content or chlorophylla concentration are identified. A comparison between the different applied techniques to determine the critical bed shear stresses reveals values in the same order of magnitude; however, some significant variations occur because of different hydromorphological conditions and the different limitations for each device.
Markus Noack; Felix Beckers; Stefan Haun; Silke Wieprecht. Investigation the stability of reservoir sediments in the lab and field. MATEC Web of Conferences 2018, 246, 01002 .
AMA StyleMarkus Noack, Felix Beckers, Stefan Haun, Silke Wieprecht. Investigation the stability of reservoir sediments in the lab and field. MATEC Web of Conferences. 2018; 246 ():01002.
Chicago/Turabian StyleMarkus Noack; Felix Beckers; Stefan Haun; Silke Wieprecht. 2018. "Investigation the stability of reservoir sediments in the lab and field." MATEC Web of Conferences 246, no. : 01002.
This study presents an experimental approach to investigate cohesive reservoir sediments. It is shown, how adjacent sediment cores can be extracted from reservoir beds with a Frahm Sediment Sampler. The cores are subsequently used for detailed investigations in a hydraulic laboratory. In a first step, related cores are identified based on their bulk density profiles. One part of the related cores is used to analyze the sediment properties over depth by means of potential stability parameters. The other part is used to determine the depth-dependent erosion stability in an erosion flume (SETEG-system). In the SETEG-system, a photogrammetric method is applied to measure the erosion rates of pre-defined sediment layers at different exposed shear stresses. Subsequently, the critical shear stress can be derived, which leads to an objective evaluation and allows a systematic approach. Finally, both results are combined to investigate possible correlations between the evaluated depth-dependent stability parameters and the measured erosion stability. The approach is presented on sediment cores from the case study “Kleiner Brombachsee”, a reservoir that is located in Middle Franconia, Germany.
Felix Beckers; Stefan Haun; Markus Noack. Experimental investigation of reservoir sediments. E3S Web of Conferences 2018, 40, 03030 .
AMA StyleFelix Beckers, Stefan Haun, Markus Noack. Experimental investigation of reservoir sediments. E3S Web of Conferences. 2018; 40 ():03030.
Chicago/Turabian StyleFelix Beckers; Stefan Haun; Markus Noack. 2018. "Experimental investigation of reservoir sediments." E3S Web of Conferences 40, no. : 03030.
This work presents a novel high-resolution photogrammetric measuring technique (PHOTOSED) to study in detail the erosion behavior of cohesive sediments, or cohesive/non-cohesive sediment mixtures. PHOTOSED uses a semiconductor laser to project a pseudo-random pattern of light points on a sediment surface and applies the Dense Optical Flow (DOF) algorithm to measure the erosion volume based on displacements of the projected light points during the sediment erosion process. Based on intensive calibration and verification experiments, the accuracy and applicability of the method has been validated for a wide range of erosion volumes, encompassing several orders of magnitude, which is required for investigations of natural sediment mixtures. The high spatial resolution of PHOTOSED is especially designed to detect the substantial variability of erosion rates during exemplary erosion experiments, which allows for further in-depth investigations of the erosion process of cohesive sediments and cohesive/non-cohesive sediment mixtures.
Markus Noack; Gerhard Schmid; Felix Beckers; Stefan Haun; Silke Wieprecht. PHOTOSED—PHOTOgrammetric Sediment Erosion Detection. Geosciences 2018, 8, 243 .
AMA StyleMarkus Noack, Gerhard Schmid, Felix Beckers, Stefan Haun, Silke Wieprecht. PHOTOSED—PHOTOgrammetric Sediment Erosion Detection. Geosciences. 2018; 8 (7):243.
Chicago/Turabian StyleMarkus Noack; Gerhard Schmid; Felix Beckers; Stefan Haun; Silke Wieprecht. 2018. "PHOTOSED—PHOTOgrammetric Sediment Erosion Detection." Geosciences 8, no. 7: 243.
Urban rivers are socioecological systems, and restored habitats may be attractive to both sensitive species and recreationists. Understanding the potential conflicts between ecological and recreational values is a critical issue for the development of a sustainable river-management plan. Habitat models are very promising tools for the ecological evaluation of river restoration projects that are already concluded, ongoing, or even to be planned. With our paper, we make a first attempt at integrating recreational user pressure into habitat modeling. The objective of this study was to analyze whether human impact is likely to hinder the re-establishment of a target species despite the successful restoration of physical habitat structures in the case of the restoration of the Isar River in Munich (Germany) and the target fish species Chondostroma nasus L. Our analysis combined high-resolution 2D hydrodynamic modeling with mapping of recreational pressure and used an expert-based procedure for modeling habitat suitability. The results are twofold: (1) the restored river contains suitable physical habitats for population conservation but has low suitability for recruitment; (2) densely used areas match highly suitable habitats for C. nasus. In the future, the integrated modeling procedure presented here may allow ecological refuge for sensitive target species to be included in the design of restoration and may help in the development of visitor-management plans to safeguard biodiversity and recreational ecosystem services.
Aude Zingraff-Hamed; Markus Noack; Sabine Greulich; Kordula Schwarzwälder; Karl Matthias Wantzen; Stephan Pauleit. Model-Based Evaluation of Urban River Restoration: Conflicts between Sensitive Fish Species and Recreational Users. Sustainability 2018, 10, 1747 .
AMA StyleAude Zingraff-Hamed, Markus Noack, Sabine Greulich, Kordula Schwarzwälder, Karl Matthias Wantzen, Stephan Pauleit. Model-Based Evaluation of Urban River Restoration: Conflicts between Sensitive Fish Species and Recreational Users. Sustainability. 2018; 10 (6):1747.
Chicago/Turabian StyleAude Zingraff-Hamed; Markus Noack; Sabine Greulich; Kordula Schwarzwälder; Karl Matthias Wantzen; Stephan Pauleit. 2018. "Model-Based Evaluation of Urban River Restoration: Conflicts between Sensitive Fish Species and Recreational Users." Sustainability 10, no. 6: 1747.
Common methods for in-situ determination of porosity of river bed material are time- and effort-consuming. Although mathematical predictors can be used for estimation, they do not adequately represent porosities. The objective of this study was to assess a new approach for the determination of porosity of frozen sediment samples. The method is based on volume determination by applying Structure-from-Motion with Multi View Stereo (SfM-MVS) to estimate a 3D volumetric model based on overlapping imagery. The method was applied on artificial sediment mixtures as well as field samples. In addition, the commonly used water replacement method was applied to determine porosities in comparison with the SfM-MVS method. We examined a range of porosities from 0.16 to 0.46 that are representative of the wide range of porosities found in rivers. SfM-MVS performed well in determining volumes of the sediment samples. A very good correlation (r = 0.998, p < 0.0001) was observed between the SfM-MVS and the water replacement method. Results further show that the water replacement method underestimated total sample volumes. A comparison with several mathematical predictors showed that for non-uniform samples the calculated porosity based on the standard deviation performed better than porosities based on the median grain size. None of the predictors were effective at estimating the porosity of the field samples.
Lydia Seitz; Christian Haas; Markus Noack; Silke Wieprecht. From picture to porosity of river bed material using Structure-from-Motion with Multi-View-Stereo. Geomorphology 2018, 306, 80 -89.
AMA StyleLydia Seitz, Christian Haas, Markus Noack, Silke Wieprecht. From picture to porosity of river bed material using Structure-from-Motion with Multi-View-Stereo. Geomorphology. 2018; 306 ():80-89.
Chicago/Turabian StyleLydia Seitz; Christian Haas; Markus Noack; Silke Wieprecht. 2018. "From picture to porosity of river bed material using Structure-from-Motion with Multi-View-Stereo." Geomorphology 306, no. : 80-89.
The increase in minimum flows has rarely been considered to mitigate the ecological impact of hydroelectric power plants because it requires a site-specific design and expensive long-term monitoring procedure to identify the most beneficial scenario. This study presents a model-based method to estimate, within the model constraints, the most sustainable scenario of water resource sharing between nature and human needs. We studied physical habitat suitability of the Isar River in Munich (Germany) for three protected fish species: Thymallus thymallus L., Hucho hucho L., and Chondostroma nasus L. The analysis combined a high-resolution two-dimensional (2D) hydromorphological model with expert-based procedures using Computer Aided Simulation Model for Instream Flow Requirements (CASiMIR). We simulated a range of minimum discharges from 5 to 68.5 m³/s and four scenarios: (A) maximum use of the resource for humans; (B) slight increase in the minimum water flow; (C) medium increase in the minimum water flow; and, (D) without diversion for hydroelectric production. Under the current hydromorphological conditions, model outputs showed that different life stages of the fish species showed preferences for different scenarios, and that none of the four scenarios provided permanently suitable habitat conditions for the three species. We suggest that discharge management should be combined with hydromorphological restoration actions to re-establish parts of the modified channel slope and/or parts of the previously lost floodplain habitat in order to implement a solution that favors all species at the same time. The modeling procedure that is presented may be helpful to identify the discharge scenario that is most efficient for maintaining target fish species under realistic usage conditions.
Aude Zingraff-Hamed; Markus Noack; Sabine Greulich; Kordula Schwarzwälder; Stephan Pauleit; Karl M. Wantzen. Model-Based Evaluation of the Effects of River Discharge Modulations on Physical Fish Habitat Quality. Water 2018, 10, 374 .
AMA StyleAude Zingraff-Hamed, Markus Noack, Sabine Greulich, Kordula Schwarzwälder, Stephan Pauleit, Karl M. Wantzen. Model-Based Evaluation of the Effects of River Discharge Modulations on Physical Fish Habitat Quality. Water. 2018; 10 (4):374.
Chicago/Turabian StyleAude Zingraff-Hamed; Markus Noack; Sabine Greulich; Kordula Schwarzwälder; Stephan Pauleit; Karl M. Wantzen. 2018. "Model-Based Evaluation of the Effects of River Discharge Modulations on Physical Fish Habitat Quality." Water 10, no. 4: 374.
Markus Noack; Heide Friedrich; Jochen Aberle. Introduction to the special issue of the 13th International Symposium on River Sedimentation, Stuttgart, Germany: Experimental and measuring/monitoring research related to sediment issues. International Journal of Sediment Research 2018, 33, 1 -2.
AMA StyleMarkus Noack, Heide Friedrich, Jochen Aberle. Introduction to the special issue of the 13th International Symposium on River Sedimentation, Stuttgart, Germany: Experimental and measuring/monitoring research related to sediment issues. International Journal of Sediment Research. 2018; 33 (1):1-2.
Chicago/Turabian StyleMarkus Noack; Heide Friedrich; Jochen Aberle. 2018. "Introduction to the special issue of the 13th International Symposium on River Sedimentation, Stuttgart, Germany: Experimental and measuring/monitoring research related to sediment issues." International Journal of Sediment Research 33, no. 1: 1-2.
The critical shear stress of cohesive and mixed cohesive/non-cohesive sediments is affected by multiple interacting physical, chemical and biological parameters. There are various mathematical approaches in the scientific literature for computing critical shear stress. However, processes that influence sediment stability are still not fully understood, and available formulas differ considerably. These discrepancies in the literature arise from random system behaviour (natural variability of the sediments), different definitions of the critical shear stress, different measurement techniques and different model frameworks (scope of the parameters, undisturbed versus artificial sediment samples). While analytical approaches fail to address the involved uncertainties, fuzzy logic-based models integrate uncertainty and imprecision. With this in mind, a data-driven neuro-fuzzy model (ANFIS) was used to determine the critical shear stress based on sediment characteristics such as wet bulk density and grain size distribution. In order to select model predictors systematically, an automated stepwise regression algorithm was applied. The database for this analysis consisted of 447 measurements of the critical shear stress originating from 64 undisturbed sediment samples. The study identified clay content as the primarily controlling variable for erosion resistance. Depending on the characteristics of the sampling location, the bulk density was also selected as a model predictor. In comparison to analytical models that are available in the scientific literature, the fuzzy model achieved higher correlation coefficients between measured and predicted data. The neuro-fuzzy-model includes uncertainties of input variables and their interactions directly. Thus, it provides a reliable method for the prediction of erosion thresholds of cohesive/non-cohesive mixtures. It was also shown that this approach requires fewer measured variables as well as fewer assumptions than the models it was compared to.
Aline Schäfer Rodrigues Silva; Markus Noack; Dirk Schlabing; Silke Wieprecht. A data-driven fuzzy approach to simulate the critical shear stress of mixed cohesive/non-cohesive sediments. Journal of Soils and Sediments 2017, 18, 3070 -3081.
AMA StyleAline Schäfer Rodrigues Silva, Markus Noack, Dirk Schlabing, Silke Wieprecht. A data-driven fuzzy approach to simulate the critical shear stress of mixed cohesive/non-cohesive sediments. Journal of Soils and Sediments. 2017; 18 (10):3070-3081.
Chicago/Turabian StyleAline Schäfer Rodrigues Silva; Markus Noack; Dirk Schlabing; Silke Wieprecht. 2017. "A data-driven fuzzy approach to simulate the critical shear stress of mixed cohesive/non-cohesive sediments." Journal of Soils and Sediments 18, no. 10: 3070-3081.
Understanding the dynamics of settling, consolidation and remobilization of cohesive and contaminated sediment is an important requirement to assess the risk of erosion and to manage mud-dominated ecosystems. Here, we present data on the erodibility of cohesive sediments from the impounded Upper Rhine River and develop a modelling concept to understand the suspended sediment dynamics along the impounded Upper Rhine. The conceptual framework includes 10 reservoirs of the Upper Rhine between Basel and Iffezheim, which serve as long-term sinks of cohesive sediment. Each reservoir is represented by a 1D sediment budget model, which is coupled to its upstream and downstream neighbour. In this paper, we focus on the uncertainty associated with the measurement of the erodibility of cohesive sediments and on the implications to model the risk of erosion. The statistical analysis showed a large uncertainty of the estimated critical shear stresses and erosion rates. Root mean square errors are in the order of 50% and 100% of the average critical shear stresses and average erosion rates, respectively. Preliminary model results are in good agreement with bed changes of the Iffezheim reservoir, which were measured using approximately quarterly echo-soundings of the reservoir. The probabilistic approach that is based on Monte-Carlo simulations allows assessing the uncertainty related to our limited knowledge (i) of the dynamics of contaminated sediments and (ii) of the environmental conditions in the reservoir that control the risk of erosion of contaminated sediments.
Thomas Hoffmann; Gudrun Hillebrand; Markus Noack. Uncertainty analysis of settling, consolidation and resuspension of cohesive sediments in the Upper Rhine. International Journal of River Basin Management 2017, 15, 401 -411.
AMA StyleThomas Hoffmann, Gudrun Hillebrand, Markus Noack. Uncertainty analysis of settling, consolidation and resuspension of cohesive sediments in the Upper Rhine. International Journal of River Basin Management. 2017; 15 (4):401-411.
Chicago/Turabian StyleThomas Hoffmann; Gudrun Hillebrand; Markus Noack. 2017. "Uncertainty analysis of settling, consolidation and resuspension of cohesive sediments in the Upper Rhine." International Journal of River Basin Management 15, no. 4: 401-411.
In sediment transport modeling, several sources of uncertainty exist that impinge on the variability of model results. Therefore, it is essential to conduct an uncertainty analysis to quantify the impact of these uncertainties, to detect regions of enhanced sensitivity and subsequently to determine a range of possible model outcomes. The first-order second moment method with numerical differentiation is applied to assess the uncertainties of a 2D sediment transport model Hydro_FT-2D at the Lower River Salzach. In comparison to other methods, the first-order second moment method has benefits in terms of total time requirement since it uses considerably less simulation runs to determine model uncertainty. In total, eight uncertain parameters are investigated including both model and river specific parameters. For this purpose, only 2n + 1 simulation runs are necessary leading to a total of 17 simulations. The results are evaluated against a reference simulation regarding bed elevation changes, bed load transport rates, grain size distribution, and total riverbed evolution volume. The results of the total riverbed evolution volume indicate a large influence of the investigated river specific parameters roughness of river channel (kst), grain roughness (ks), and bed load input rate of the upstream River Saalach (QS SAAL). Among the model specific parameters, the critical Shields parameter (θcrit) and the scaling factor of Meyer-Peter and Mueller equation (MPM) have a significant effect on the model results. Moreover, a spatial evaluation of the maximum and minimum parameter-specific deviation from the reference indicates sensitive areas in regions with poor descriptive data as well as in close vicinity to weirs, ramps, and lateral inflows. In these areas, the model predictions are subject to a high degree of uncertainty and have to be taken with caution. The applied first-order second moment method with numerical differentiation is a powerful method to identify sensitive areas within the numerical model and to gain knowledge on both uncertain model and river specific parameters. Based on the results, the variability of model outputs can be evaluated and assessed with respect to the uncertainty in the input parameters and can thus contribute to a deeper understanding of the model behavior, which is highly beneficial for long-term morphodynamic studies. The method is found to be applicable for sediment transport models especially in an applied engineering context and for long-term simulation runs due to the simplicity of implementation as well as the reasonable total time requirement.
Felix Beckers; Markus Noack; Silke Wieprecht. Uncertainty analysis of a 2D sediment transport model: an example of the Lower River Salzach. Journal of Soils and Sediments 2017, 18, 3133 -3144.
AMA StyleFelix Beckers, Markus Noack, Silke Wieprecht. Uncertainty analysis of a 2D sediment transport model: an example of the Lower River Salzach. Journal of Soils and Sediments. 2017; 18 (10):3133-3144.
Chicago/Turabian StyleFelix Beckers; Markus Noack; Silke Wieprecht. 2017. "Uncertainty analysis of a 2D sediment transport model: an example of the Lower River Salzach." Journal of Soils and Sediments 18, no. 10: 3133-3144.
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.
Giuseppe Roberto Pisaturo; Maurizio Righetti; Michael Dumbser; Markus Noack; Matthias Schneider; Valentina Cavedon. The role of 3D-hydraulics in habitat modelling of hydropeaking events. Science of The Total Environment 2017, 575, 219 -230.
AMA StyleGiuseppe Roberto Pisaturo, Maurizio Righetti, Michael Dumbser, Markus Noack, Matthias Schneider, Valentina Cavedon. The role of 3D-hydraulics in habitat modelling of hydropeaking events. Science of The Total Environment. 2017; 575 ():219-230.
Chicago/Turabian StyleGiuseppe Roberto Pisaturo; Maurizio Righetti; Michael Dumbser; Markus Noack; Matthias Schneider; Valentina Cavedon. 2017. "The role of 3D-hydraulics in habitat modelling of hydropeaking events." Science of The Total Environment 575, no. : 219-230.
The first-order scatter analysis is applied to assess the reliability and uncertainties of a 2D sediment transport model of the lower River Salzach. In comparison to other reliability methods (e.g. Monte-Carlo analysis), the scatter analysis has benefits in terms of time requirement since it uses considerably less simulation runs to determine a model’s reliability. In total, eight parameters are investigated including both model and river specific parameters. The results are evaluated against a reference simulation regarding bed elevation changes, bed load transport rates, grain size distribution and total riverbed evolution volume. In general, the results show a large influence of the investigated river specific parameters and transport relevant parameters. Moreover, a spatial evaluation indicates sensitive areas in regions with poor descriptive data as well as in close vicinity to weirs, ramps and lateral inflows. The applied scatter-analysis is found to be applicable to identify sensitive areas and to assess the model reliability.
F. Beckers; Markus Noack; Silke Wieprecht. Reliability analysis of a 2D sediment transport model: An example of the lower river Salzach. River Sedimentation 2016, 147 -152.
AMA StyleF. Beckers, Markus Noack, Silke Wieprecht. Reliability analysis of a 2D sediment transport model: An example of the lower river Salzach. River Sedimentation. 2016; ():147-152.
Chicago/Turabian StyleF. Beckers; Markus Noack; Silke Wieprecht. 2016. "Reliability analysis of a 2D sediment transport model: An example of the lower river Salzach." River Sedimentation , no. : 147-152.
This study aims at investigating possible colmation effects of the river bed of a residual flow reach of the river Brixentaler Ache in Austria. Therefore, three sites within the residual flow reach are investigated and compared to three sites that are located up- and downstream of the residual flow reach. In order to investigate the current state of the river bed with respect to colmation, three methods are applied and combined in this study, namely: substrate mapping, sediment sampling and dissolved oxygen measurements in the hyporheic zone. The results from the substrate mapping show almost no colmation within the main stream, neither in the residual flow stretch nor in the reference stretches. Only close to the river banks outer colmation areas are mapped along the river stretches. In addition, the sediment analyses confirm the visual observations. Although, a high degree of fine sediments within the river bed could be measured in both residual and reference reaches almost no cohesive material is found. Hence, the obtained data show no evidence of negative effects on the river substrate quality due to the water diversion has negative effects at the the Brixentaler Ache. This is also proved by the measurements of the dissolved oxygen in the hyporheic zone.
L. Seitz; Markus Noack; Stefan Haun; R. Reindl; G. Senn; M. Schletterer. Analysing sediment characteristics of the alpine River Brixentaler Ache (Austria) including in-situ measurements of dissolved oxygen. River Sedimentation 2016, 915 -921.
AMA StyleL. Seitz, Markus Noack, Stefan Haun, R. Reindl, G. Senn, M. Schletterer. Analysing sediment characteristics of the alpine River Brixentaler Ache (Austria) including in-situ measurements of dissolved oxygen. River Sedimentation. 2016; ():915-921.
Chicago/Turabian StyleL. Seitz; Markus Noack; Stefan Haun; R. Reindl; G. Senn; M. Schletterer. 2016. "Analysing sediment characteristics of the alpine River Brixentaler Ache (Austria) including in-situ measurements of dissolved oxygen." River Sedimentation , no. : 915-921.
Understanding the dynamics of erosion and deposition of cohesive and contaminated sediment is an important requirement to assess the risk of erosion and to manage mud-dominated ecosystems. Here, we present data on the erodibility of cohesive sediments from the impounded Upper Rhine River and develop a modelling concept to understand the sediment dynamics at large spatial scale (∼164 km) and long time scale (∼30 years). The conceptual framework includes ten reservoirs of the Upper Rhine between Basel and Iffezheim, which serve as long-term sinks of cohesive sediment. Each reservoir is represented by a 1D sediment budget model, which is coupled to its upstream and downstream neighbour. In this paper, we focus on the uncertainty associated with the measurement of the erodibility of cohesive sediments and on the implications to model the risk of erosion. Therefore, preliminary model results of the bed changes of the Iffezheim reservoir are presented and evaluated with empirical evidences from quarterly echo-soundings of the reservoir. The probabilistic approach that is based on Monte Carlo simulations allows to assess the uncertainty related to our limited knowledge i) of the dynamics of contaminated sediments and ii) of the environmental conditions in the reservoir that control the risk of erosion of contaminated sediments.
T. Hoffmann; G. Hillebrand; Markus Noack. Modelling deposition, consolidation and erosion of cohesive sediments in the Upper Rhine. River Sedimentation 2016, 1024 -1029.
AMA StyleT. Hoffmann, G. Hillebrand, Markus Noack. Modelling deposition, consolidation and erosion of cohesive sediments in the Upper Rhine. River Sedimentation. 2016; ():1024-1029.
Chicago/Turabian StyleT. Hoffmann; G. Hillebrand; Markus Noack. 2016. "Modelling deposition, consolidation and erosion of cohesive sediments in the Upper Rhine." River Sedimentation , no. : 1024-1029.
G. Pisaturo; M Righetti; M Dumbser; M Noack; M Schneider; I Kopecki; V Cavedon. The role of 3D-hydraulics in habitat modelling of hydropeaking events. River Flow 2016 2016, 1 .
AMA StyleG. Pisaturo, M Righetti, M Dumbser, M Noack, M Schneider, I Kopecki, V Cavedon. The role of 3D-hydraulics in habitat modelling of hydropeaking events. River Flow 2016. 2016; ():1.
Chicago/Turabian StyleG. Pisaturo; M Righetti; M Dumbser; M Noack; M Schneider; I Kopecki; V Cavedon. 2016. "The role of 3D-hydraulics in habitat modelling of hydropeaking events." River Flow 2016 , no. : 1.
M Noack; G Schmid; M Thom; Silke Wieprecht. Testing ‘Structure-from-Motion’ photogrammetry for high-resolution topographic surveys in hydraulic laboratories. River Flow 2016 2016, 1 .
AMA StyleM Noack, G Schmid, M Thom, Silke Wieprecht. Testing ‘Structure-from-Motion’ photogrammetry for high-resolution topographic surveys in hydraulic laboratories. River Flow 2016. 2016; ():1.
Chicago/Turabian StyleM Noack; G Schmid; M Thom; Silke Wieprecht. 2016. "Testing ‘Structure-from-Motion’ photogrammetry for high-resolution topographic surveys in hydraulic laboratories." River Flow 2016 , no. : 1.
We introduce the lateral line probe (LLP) as a measurement device for natural flows.Hydraulic surveys in rivers and hydraulic structures are currently based on time-averaged velocity measurements using propellers or acoustic Doppler devices. The long-term goal is thus to develop a sensor system, which includes spatial gradients of the flow field along a fish-shaped sensor body. Interpreting the biological relevance of a collection of point velocity measurements is complicated by the fact that fish and other aquatic vertebrates experience the flow field through highly dynamic fluid-body interactions. To collect body-centric flow data, a bioinspired fish-shaped probe is equipped with a lateral line pressure sensing array, which can be applied both in the laboratory and in the field. Our objective is to introduce a new type of measurement device for body-centric data and compare its output to estimates of conventional point-based technologies. We first provide the calibration workflow for laboratory investigations. We then provide a review of two velocity estimation workflows, independent of calibration. Such workflows are required as existing field investigations consist of measurements in environments where calibration is not feasible. The mean difference for uncalibrated LLP velocity estimates from 0 to 50 cm/s under in a closed flow tunnel and open channel flume was within 4 cm/s when compared to conventional measurement techniques. Finally, spatial flow maps in a scale vertical slot fishway are compared for the LLP, direct measurements, and 3D numerical models where it was found that the LLP provided a slight overestimation of the current velocity in the jet and underestimated the velocity in the recirculation zone.
J. A. Tuhtan; J. F. Fuentes-Pérez; N. Strokina; G. Toming; M. Musall; M. Noack; J. K. Kämäräinen; M. Kruusmaa. Design and application of a fish-shaped lateral line probe for flow measurement. Review of Scientific Instruments 2016, 87, 045110 .
AMA StyleJ. A. Tuhtan, J. F. Fuentes-Pérez, N. Strokina, G. Toming, M. Musall, M. Noack, J. K. Kämäräinen, M. Kruusmaa. Design and application of a fish-shaped lateral line probe for flow measurement. Review of Scientific Instruments. 2016; 87 (4):045110.
Chicago/Turabian StyleJ. A. Tuhtan; J. F. Fuentes-Pérez; N. Strokina; G. Toming; M. Musall; M. Noack; J. K. Kämäräinen; M. Kruusmaa. 2016. "Design and application of a fish-shaped lateral line probe for flow measurement." Review of Scientific Instruments 87, no. 4: 045110.
The incubation period represents an important development phase for successful reproduction of gravel-spawning fish, whereby colmation processes can affect the quality of the interstitial habitat. From a sedimentary perspective, the infiltration and accumulation of fine sediments can result in a reduction of the pore space and limit the transport of oxygen-rich surface water in the interstitials of riverbeds. From a biogeochemical perspective, the increased surface area for microbial growth can lead to an increase of respiration rates, which additionally limits the oxygen supply. The assessment and prediction of such processes on interstitial habitat quality represents a challenging task given their complex dynamic interacting processes and their high spatio-temporal variability. This study presents a new habitat-based modelling approach, which simulates interstitial habitat suitability (IHS) to evaluate dynamically the quality of interstitial habitat conditions during incubation. For this purpose, three key parameters (hydraulic conductivity, interstitial temperature and hyporheic respiration) are linked to the habitat requirements of different developmental stages during the incubation period (egg, hatching, larvae) via a multivariate fuzzy approach. The proposed modelling concept has been developed on the River Spoel in Switzerland, whereby results of a numerical 3D sediment transport model, together with supplementary measurements, deliver the spatio-temporal variations of the required input data. The fuzzy approach provides results in form of maps and time series of IHS values to allow for an identification of abiotic bottlenecks during the incubation period. Hence, this approach represents a significant contribution for the restoration of reproduction areas of gravel-spawning fish. Copyright © 2016 John Wiley & Sons, Ltd.
M. Noack; J. Ortlepp; Silke Wieprecht. An Approach to Simulate Interstitial Habitat Conditions During the Incubation Phase of Gravel-Spawning Fish. River Research and Applications 2016, 33, 192 -201.
AMA StyleM. Noack, J. Ortlepp, Silke Wieprecht. An Approach to Simulate Interstitial Habitat Conditions During the Incubation Phase of Gravel-Spawning Fish. River Research and Applications. 2016; 33 (2):192-201.
Chicago/Turabian StyleM. Noack; J. Ortlepp; Silke Wieprecht. 2016. "An Approach to Simulate Interstitial Habitat Conditions During the Incubation Phase of Gravel-Spawning Fish." River Research and Applications 33, no. 2: 192-201.
The aim of this study is to investigate discharge rates at which a flow hydrograph becomes relevant for bed load transport on the example of the Alpine river Saalach. Two characteristic flow hydrographs of the river Saalach are selected and reduced to discharges above pre-specified values. With each set of reduced hydrographs, a 2D morphological simulation is conducted. Two important morphological parameters, namely total river bed evolution (i) and sorting effects of the active layer (ii) are analyzed and evaluated. Moreover, an additional simulation is conducted with a linearly increasing flow hydrograph as boundary condition to analyze the initiation of bed load transport as a function of discharge (iii). The results are analyzed and evaluated with respect to the total sediment output at the downstream boundary of the model and at some inner control sections to validate the findings for (i) and (ii). The model results show: (i) For regions with fine bed materials, discharge thresholds between 100 and 130 m3/s and for regions with mainly coarse bed materials discharge thresholds in the range between 150 and 180 m3/s can be identified as relevant discharges for bed load transport and may be used for reducing hydrographs without affecting the accuracy of the model results; (ii) The active layer shows no obvious changes in the mean diameter of sediments for all tested hydrographs. (iii) The investigations with a linearly increasing flow hydrograph show that the sediment output from the investigated river reaches increase significantly for discharges exceeding 150 m3/s.
Najibullah Sadid; Felix Beckers; Markus Noack; Stefan Haun; Silke Wieprecht. An Evolution Volume Balance Approach to Determine Relevant Discharge Threshold for Bed Load Transport. Flood Risk in the Upper Vistula Basin 2016, 307 -318.
AMA StyleNajibullah Sadid, Felix Beckers, Markus Noack, Stefan Haun, Silke Wieprecht. An Evolution Volume Balance Approach to Determine Relevant Discharge Threshold for Bed Load Transport. Flood Risk in the Upper Vistula Basin. 2016; ():307-318.
Chicago/Turabian StyleNajibullah Sadid; Felix Beckers; Markus Noack; Stefan Haun; Silke Wieprecht. 2016. "An Evolution Volume Balance Approach to Determine Relevant Discharge Threshold for Bed Load Transport." Flood Risk in the Upper Vistula Basin , no. : 307-318.