Ojha et al. (2026) A comprehensive assessment and comparison of streamflow simulations performance between the national water model versions 3.0 and 2.1 across the continental United States

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-07-16
• Authors: Ashish Ojha, Haowen Yue, Kendra M. Dresback, Long Jiang, Tiantian Yang
• DOI: 10.1016/j.jhydrol.2026.136046

Research Groups

• School of Civil Engineering and Environmental Science, University of Oklahoma
• State Key Laboratory of Climate Resilience for Coastal Cities, Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University
• School for Environment and Sustainability, University of Michigan

Short Summary

This study evaluates the performance of National Water Model version 3.0 (NWMv3.0) in simulating streamflow across the continental United States, comparing it to its predecessor NWMv2.1.

Objective

• Evaluate the performance of NWMv3.0 and NWMv2.1 in simulating daily flow and annual peak-flow statistics across spatial, seasonal, and categorical dimensions.

Study Configuration

• Spatial Scale: Continental United States (CONUS)
• Temporal Scale: 1979–2020

Methodology and Data

• Models used: National Water Model version 3.0 (NWMv3.0) and version 2.1 (NWMv2.1)
• Data sources: Observed streamflow from over 4300 United States Geological Survey (USGS) gages

Main Results

• NWMv3.0 generally outperformed NWMv2.1 in both daily flow and peak flow statistics, with improvements in Kling-Gupta Efficiency (KGE), Percent Bias (PBIAS), Average Annual Peak Flow Bias (AAPFB), and Average Annual Peak Timing Error (AAPTE).
• Spatial variability in performance highlights the need for region-specific refinements in future NWM development.

Contributions

• This study provides a comprehensive evaluation of NWMv3.0's performance, highlighting its strengths and weaknesses compared to NWMv2.1.
• The results provide valuable insights for improving the accuracy of streamflow simulations across CONUS.

Funding

• Not specified

Citation

@article{Ojha2026comprehensive,
  author = {Ojha, Ashish and Yue, Haowen and Dresback, Kendra M. and Jiang, Long and Yang, Tiantian},
  title = {A comprehensive assessment and comparison of streamflow simulations performance between the national water model versions 3.0 and 2.1 across the continental United States},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136046},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136046}
}