The effects of spatial resolution and dimensionality on modeling regional-scale hydraulics in a multichannel river

Elizabeth H. Altenau*, Tamlin M. Pavelsky, Paul D. Bates, Jeffrey C. Neal

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

19 Citations (Scopus)
291 Downloads (Pure)


As modeling capabilities at regional and global scales improve, questions remain regarding the appropriate process representation required to accurately simulate multichannel river hydraulics. This study uses the hydrodynamic model LISFLOOD-FP to simulate patterns of water surface elevation (WSE), depth, and inundation extent across a ∼90 km, anabranching reach of the Tanana River, Alaska. To provide boundary conditions, we collected field observations of bathymetry and WSE during a 2 week field campaign in summer 2013. For the first time at this scale, we test a simple, raster-based model's capabilities to simulate 2-D, in-channel patterns of WSE and inundation extent. Additionally, we compare finer resolution (≤25 m) 2-D models to four other models of lower dimensionality and coarser resolution (100-500 m) to determine the effects of simplifying process representation. Results indicate that simple, raster-based models can accurately simulate 2-D, in-channel hydraulics in the Tanana. Also, the fine-resolution, 2-D models produce lower errors in spatiotemporal outputs of WSE and inundation extent compared to coarse-resolution, 1-D models: 22.6 cm versus 56.4 cm RMSE for WSE, and 90% versus 41% Critical Success Index values for simulating inundation extent. Incorporating the anabranching channel network using subgrid representations for smaller channels is important for simulating accurate hydraulics and lowers RMSE in spatially distributed WSE by at least 16%. As a result, better representation of the converging and diverging multichannel network by using subgrid solvers or downscaling techniques in multichannel rivers is needed to improve errors in regional to global-scale models.

Original languageEnglish
Pages (from-to)1683–1701
Number of pages19
JournalWater Resources Research
Issue number2
Early online date25 Feb 2017
Publication statusPublished - Feb 2017


  • 1-D/2-D modeling
  • Dimensionality
  • Hydrodynamic modeling
  • Hydrology
  • Multichannel rivers
  • Resolution

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