Preprints
https://doi.org/10.5194/egusphere-2026-881
https://doi.org/10.5194/egusphere-2026-881
05 Mar 2026
 | 05 Mar 2026

Integrating reservoirs and lakes in the CoSWAT global hydrological model

Jose P. Teran, Celray J. Chawanda, Albert Nkwasa, Inne Vanderkelen, Jeffrey G. Arnold, and Ann Van Griensven

Abstract. Global water models are essential tools for assessing water resource challenges in the context of climate change, land use changes, and human activities. The CoSWAT Global Water model is a global application of the Soil and Water Assessment Tool (SWAT +). It is a high-resolution tool designed to simulate water systems using a basin-oriented structure. The CoSWAT model currently lacks a realistic representation of reservoirs and lakes, limiting its ability to adequately represent basins where these water bodies play a significant hydrological role. The scarcity and limited accessibility of global reservoir operation or lake outflow data make it challenging to represent these water bodies with the current tools that SWAT+ supports, particularly at a global scale. In this study, we address this limitation by combining commonly used reservoir and lake modelling schemes from other global water models and the capabilities of SWAT+. Moreover, to model irrigation reservoirs, we implemented an approach that combines global datasets with a topological method to estimate irrigation demand for each reservoir. With these new implementations, the CoSWAT model was restructured for selected regions worldwide, where validation of reservoir or lake storage, inflow, and outflow was performed, and the impact of these implementations on streamflow performance was assessed. The results show that the model captures storage dynamics with reasonable performance, comparable to other state-of-the-art global models, and demonstrate a general improvement (70 % of evaluated stations) in streamflow representation following the integration of these water bodies. The new methodological advancements represent a substantial improvement for the CoSWAT global model, enabling more robust and realistic assessments of inland water systems at the global scale.

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Journal article(s) based on this preprint

29 Jul 2026
Integrating reservoirs and lakes in the CoSWAT global hydrological model
Jose P. Teran, Celray J. Chawanda, Albert Nkwasa, Inne Vanderkelen, Jeffrey G. Arnold, and Ann Van Griensven
Geosci. Model Dev., 19, 6879–6907, https://doi.org/10.5194/gmd-19-6879-2026,https://doi.org/10.5194/gmd-19-6879-2026, 2026
Short summary
Jose P. Teran, Celray J. Chawanda, Albert Nkwasa, Inne Vanderkelen, Jeffrey G. Arnold, and Ann Van Griensven

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2026-881', Anonymous Referee #1, 11 Mar 2026
    • AC1: 'Reply on RC1', Jose Pablo Teran Orsini, 28 Apr 2026
  • RC2: 'Comment on egusphere-2026-881', Anonymous Referee #2, 20 Mar 2026
    • AC2: 'Reply on RC2', Jose Pablo Teran Orsini, 28 Apr 2026

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
AR by Jose Pablo Teran Orsini on behalf of the Authors (09 Jun 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (18 Jun 2026) by Lele Shu
RR by Anonymous Referee #2 (29 Jun 2026)
RR by Anonymous Referee #1 (30 Jun 2026)
ED: Publish as is (04 Jul 2026) by Lele Shu
AR by Jose Pablo Teran Orsini on behalf of the Authors (06 Jul 2026)

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2026-881', Anonymous Referee #1, 11 Mar 2026
    • AC1: 'Reply on RC1', Jose Pablo Teran Orsini, 28 Apr 2026
  • RC2: 'Comment on egusphere-2026-881', Anonymous Referee #2, 20 Mar 2026
    • AC2: 'Reply on RC2', Jose Pablo Teran Orsini, 28 Apr 2026

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
AR by Jose Pablo Teran Orsini on behalf of the Authors (09 Jun 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (18 Jun 2026) by Lele Shu
RR by Anonymous Referee #2 (29 Jun 2026)
RR by Anonymous Referee #1 (30 Jun 2026)
ED: Publish as is (04 Jul 2026) by Lele Shu
AR by Jose Pablo Teran Orsini on behalf of the Authors (06 Jul 2026)

Journal article(s) based on this preprint

29 Jul 2026
Integrating reservoirs and lakes in the CoSWAT global hydrological model
Jose P. Teran, Celray J. Chawanda, Albert Nkwasa, Inne Vanderkelen, Jeffrey G. Arnold, and Ann Van Griensven
Geosci. Model Dev., 19, 6879–6907, https://doi.org/10.5194/gmd-19-6879-2026,https://doi.org/10.5194/gmd-19-6879-2026, 2026
Short summary
Jose P. Teran, Celray J. Chawanda, Albert Nkwasa, Inne Vanderkelen, Jeffrey G. Arnold, and Ann Van Griensven

Data sets

Integrating reservoirs and Lakes in the CoSWAT model J. P. Teran https://doi.org/10.5281/zenodo.18733431

Model code and software

Soil and Water Assessment Tool Plus (SWAT+) J. G. Arnold et al. https://doi.org/10.5281/zenodo.18727784

CoSWAT-Framework C. J. Chawanda and J. P. Teran https://doi.org/10.5281/zenodo.18746453

Jose P. Teran, Celray J. Chawanda, Albert Nkwasa, Inne Vanderkelen, Jeffrey G. Arnold, and Ann Van Griensven

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Short summary
Global water models help us understand how human activities and climate change affect water resources. One of them is the CoSWAT Global Model. In this study we improved this model by adding a better representations of lakes, reservoirs, and irrigation demand. Evaluation shows these changes improve river flow simulation and enable explicit assessment of lake and reservoir water balances, producing a more robust tool for global freshwater studies.
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