Systematic comparison of 1D and 2D hydrodynamic models for the assessment of hydropeaking alterations

Abstract

Numerical hydrodynamic models enable the simulation of hydraulic conditions under various scenarios and are thus suitable tools for hydropeaking related assessments. However, the choice of the necessary model complexity and the consequences of modelling choices are not trivial and only few guidelines exist. In this study, we systematically evaluate numerical one-dimensional (1D) and two-dimensional (2D) hydrodynamic models with varying spatial resolution regarding their suitability as input for hydropeaking-sensitive, ecologically relevant hydraulic parameters (ERHPs), and their computational efficiency.The considered ERHPs include the vertical dewatering velocity, the wetted area variation between base and peak flow and the bed shear stress as a proxy for macroinvertebrate drift. Furthermore, we quantified the habitat suitability of brown trout for different life stages. The evaluation is conducted for three channel planforms with morphological characteristics representative for regulated Alpine Rivers, ranging from alternating bars to a braiding river morphology. For the prediction of habitat suitability and bed shear stress, a 1D model appears to be always insufficient, and a highly resolved 2D model is suggested.Reducing the spatial resolution of 2D models leads to computational efficiency similar to 1D, while providing more accurate results. Thus, our results suggest, that while a highly resolved 1D model is sufficient for accurate predictions of the dewatering velocity and wetted area in the less complex alternating bar morphology, a 2D model is recommended for more complex wandering or braiding morphologies. This study can serve as guideline for researchers and practitioners in the selection and setup of hydrodynamic models for hydropeaking.

Prediction model and consequence analysis for riverine oil spills

“…River hydrodynamics provide basic flow data for particle tracking algorithms. With the longterm development of numerical approaches for the dynamic model, a large number of mature software packages are available, and many researchers have discussed the computational performance of these models in different scenarios and scales (Jowett and Duncan, 2012;Bürgler et al, 2022). The contaminated area, which is significantly influenced by the longitudinal flow velocity, is hundreds of kilometers in length.…”

Innovations in hydropeaking research

“…The growing interest on the topic is manifested also by Alp et al (2023), which introduces a new international network on hydropeaking, underlining the importance of interdisciplinary collaboration to manage hydropeaking rivers. Overall, the contributions to the SI provide novelties at different levels, but also a valuable compendium on current methods and challenges in hydropeaking research (e.g., Alexandre et al, 2023; Bürgler et al, 2023). With a focus on the novelties on fundamental knowledge, we highlight the following contributions: while most studies focus on downstream impacts, Pander et al (2023) is among the first to investigate the ecological effects of hydropeaking upstream of the storing reservoir.…”

“…Different modelling approaches are presented in the SI: from hydraulic, temperature, and habitat modelling (e.g., Antonetti et al, 2023; Jelovica et al, 2023; Judes et al, 2023), to rule‐ or process‐based classification tools (e.g., Bakken et al, 2023; Godinho et al, 2023; Greimel et al, 2023; Reindl et al, 2023), to individual‐based models (Hajiesmaeili et al, 2023). Two contributions specifically focus on numerical hydrodynamic models: Bürgler et al (2023) presents a systematic comparison of 1D and 2D models, whilst Le Coarer et al (2023) proposes a new algorithm to enhance the quantification of stranding risk. A single contribution examines the use of remote sensed data for the investigation of fish stranding in a large river (Glowa et al, 2023).…”

Impact of interbasin transfer hydroelectric project on downstream aquatic habitat

“…A hydropeaking dam upstream can affect the biodiversity of the downstream ecosystem through hydrologic alterations (Bürgler et al, 2023; Meile et al, 2011; Moreira et al, 2019; Ray & Sarma, 2011; Wang et al, 2019). Artificial flow fluctuations due to hydropeaking can hinder the sustenance rate of aquatic organisms (Glowa et al, 2023; Greimel et al, 2018; Hedger et al, 2023).…”