Comparison of 1D and 3D reservoir heat transport models and temperature effects on mass transport

Abstract

One and three-dimensional heat transport models are compared in a dendritic reservoir in Brazil. We estimate the periods of temperature stratification for both models using physical indices and temperature gradients. The three-dimensional model reproduces more accurately the water column temperature profiles, however with focus on the physical indices (Wedderburn Number and Lake Number) similar results were obtained with both models. Secondly, we investigated the effects of temperature stratification on substance mass transport using the three-dimensional model. The advective and dispersive transport for a tracer released in a river and in a side arm of the reservoir were quantified. We identified that considering the effects of temperature stratification increased the horizontal advective transport - up to a maximum of 40% increase for the tracer released in the river, and 9% for the side arm. In relation to dispersive transport there was a decrease in transport due to temperature stratification, and no pattern was discernible for the side arm tracer modeling.

Physical mechanisms of internal seiche attenuation for non-ideal stratification and basin topography

“…The heat flux at the water surface was estimated as the sum of net longwave and solar radiation, latent and sensible heat, which were calculated from measured time-series of relative humidity, air temperature, fraction of the sky covered by clouds, short wave solar radiation, and Secchi depth. We applied the Ocean model for parameterizing the heat fluxes in Delft3D, which was successfully applied to lakes and reservoirs and presented better results for the energy loss by evaporation compared to Murakami model in former studies (Polli & Bleninger, 2019).…”

Effects of dimensionality on the performance of hydrodynamic models for stratified lakes and reservoirs

“…Comparison of models with different dimensionalities is more difficult, since the interpretation of each result also depends on model considerations and simplifications. Polli and Bleninger (2019) compared water temperature simulations of a thermally stratified reservoir using MTCR-1 (1D model) and Delft3D (3D model), and they found that 1D simulations may provide similar information as 3D models in terms of thermal structure. Therefore, the study recommended onedimensional models as a first approach for assessing reservoir stratification patterns and the application of a 3D model if the horizontal substance transport is of interest.…”