One‐dimensional and two‐dimensional hydrodynamic modeling derived flow properties: impacts on aquatic habitat quality predictions

Abstract

Studies of the effects of hydrodynamic model dimensionality on simulated flow properties and derived quantities such as aquatic habitat quality are limited. It is important to close this knowledge gap especially now that entire river networks can be mapped at the microhabitat scale due to the advent of point‐cloud techniques. This study compares flow properties, such as depth and velocity, and aquatic habitat quality predicted from pseudo‐2D and fully 2D hydrodynamic modeling. The models are supported by high‐resolution, point‐cloud derived bathymetries, from which close‐spaced cross‐sections were extracted for the 1D modeling, of three morphologically and hydraulically different river systems. These systems range from small low‐gradient meandering pool–riffle to large steep confined plane‐bed rivers. We test the effects of 1D and 2D models on predicted hydraulic variables at cross‐sections and over the full bathymetry to quantify the differences due to model dimensionality and those from interpolation. Results show that streambed features, whose size is smaller than cross‐sectional spacing, chiefly determine the different results of 1D and 2D modeling whereas flow discharge, stream size, morphological complexity and model grid sizes have secondary effects on flow properties and habitat quality for a given species and life stage predicted from 1D and 2D modeling. In general, the differences in hydraulic variables are larger in the bathymetric than in the cross‐sectional analysis, which suggests that some errors are introduced from interpolation of spatially disaggregated simulated variables with a 1D model, instead of model dimensionality 1D or 2D. Flow property differences are larger for velocity than for water surface elevation and depth. Differences in weighted usable area (WUA) derived from 1D and 2D modeling are relatively small for low‐gradient meandering pool–riffle systems, but the differences in the spatial distribution of microhabitats can be considerable although clusters of same habitat quality are spatially comparable. Copyright © 2014 John Wiley & Sons, Ltd.

Benthic Uptake Rate due to Hyporheic Exchange: The Effects of Streambed Morphology for Constant and Sinusoidally Varying Nutrient Loads

“…Figure 3 shows the contour map of the computed hyporheic residence times (Figure 3a), the categorical map of measured dissolved oxygen concentration (red contours) (Figure 3b, which corresponds to Figure 4d in Malard et al [41]) and the map of model-predicted dissolved oxygen concentrations (Figure 3c) at the sediment-water interface. The overall agreement value between the predicted and observed DO concentration distribution is 0.58, and the kappa index is 0.46, which correspond to a good agreement and are comparable to the values reported in the GIS literature [57,59,64]. Because, to our knowledge, this is the first comparison between observed and modeled spatially-distributed hyporheic quantities, we cannot compare these values with others reported in the hyporheic literature.…”

Verification of Saint-Venant equations solution based on the lax diffusive method for flow routing in natural channels

“…Some studies point out that the correct characterization of channel bed (such as roughness and slope profile) is the main factor influencing the results of hydrodynamic simulations (SALEH et al, 2013;BENJANKAR;TONINA;MCKEAN, 2015).…”

Development of an Evaluation System for Sustaining Reservoir Functions—A Case Study of Shiwen Reservoir in Taiwan

“…Lian et al [30] applied SI for optimal Danjiangkou Reservoir operations in China. For domestic water use purposes, reservoir water quality is the most important part of sustaining water supply functionality, and is the topic of many studies producing various related indicators such as the water quality index (WQI) for reservoir operations and evaluations [12,33,34]. Moreover, water quality is one popular ecological indicator in sustainable development [35].…”

“…To manage reservoir-related fish habitat issues, river habitat models can be employed to simulate changes in river flow and habitat availability under various flow scenarios. As such, weighted usable area (WUA) indices have been widely applied in habitat assessments including reservoir operations [33,[38][39][40][41][42][43]. Nikghalb et al [44] determined ecological flow using WUA, and compared these results with Q 95 results.…”