Preprints
https://doi.org/10.5194/egusphere-2025-5008
https://doi.org/10.5194/egusphere-2025-5008
21 Oct 2025
 | 21 Oct 2025

A GNN Routing Module Is All You Need for LSTM Rainfall–Runoff Models

Hamidreza Mosaffa, Florian Pappenberger, Christel Prudhomme, Matthew Chantry, Christoph Rüdiger, and Hannah Cloke

Abstract. Rainfall-Runoff (R-R) modeling is crucial for hydrological forecasting and water resource management, yet traditional deep learning approaches, such as Long Short-Term Memory (LSTM) networks, often overlook explicit runoff routing, leading to inaccuracies in complex river basins. This study introduces a novel LSTM-Graph Neural Network (GNN) framework that integrates LSTM for local runoff generation with GNN for spatial flow routing, leveraging river network topology as a directed graph. Applied to the Upper Danube River Basin using the LamaH-CE dataset (1987–2017), the model partitions the basin into 530 subbasins and evaluates four GNN architectures: Graph Convolutional Network (GCN), Graph Attention Network (GAT), Graph SAmple and aggreGatE (GraphSAGE), and Chebyshev Spectral Graph Convolutional Network (ChebNet). Results demonstrate that all LSTM-GNN architectures outperform the baseline LSTM, with LSTM-GAT achieving the highest performance (mean NSE=0.61, KGE=0.65, Correlation Coefficient=0.84, RMSE reduction of ~35 %). Improvements are most evident in downstream stations with high connectivity and large contributing areas, where adaptive attention in GAT effectively captures heterogeneous upstream influences. These findings underscore the potential of GNN-based approaches for large-scale, spatially aware hydrological modelling and provide a foundation for future applications in flood forecasting and climate adaptation.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
Share

Journal article(s) based on this preprint

15 Apr 2026
A GNN routing module is all you need for LSTM Rainfall–Runoff models
Hamidreza Mosaffa, Florian Pappenberger, Christel Prudhomme, Matthew Chantry, Christoph Rüdiger, and Hannah Cloke
Hydrol. Earth Syst. Sci., 30, 2079–2092, https://doi.org/10.5194/hess-30-2079-2026,https://doi.org/10.5194/hess-30-2079-2026, 2026
Short summary
Hamidreza Mosaffa, Florian Pappenberger, Christel Prudhomme, Matthew Chantry, Christoph Rüdiger, and Hannah Cloke

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Comment on egusphere-2025-5008', Zilin Li, 29 Oct 2025
    • AC1: 'Reply on CC1', Hamidreza Mosaffa, 09 Nov 2025
  • RC1: 'Comment on egusphere-2025-5008', Anonymous Referee #1, 12 Dec 2025
    • AC2: 'Reply on RC1', Hamidreza Mosaffa, 17 Jan 2026
  • RC2: 'Comment on egusphere-2025-5008', Uwe Ehret, 15 Dec 2025
    • AC3: 'Reply on RC2', Hamidreza Mosaffa, 17 Jan 2026
  • RC3: 'Comment on egusphere-2025-5008', Anonymous Referee #3, 23 Dec 2025
    • AC4: 'Reply on RC3', Hamidreza Mosaffa, 17 Jan 2026

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Comment on egusphere-2025-5008', Zilin Li, 29 Oct 2025
    • AC1: 'Reply on CC1', Hamidreza Mosaffa, 09 Nov 2025
  • RC1: 'Comment on egusphere-2025-5008', Anonymous Referee #1, 12 Dec 2025
    • AC2: 'Reply on RC1', Hamidreza Mosaffa, 17 Jan 2026
  • RC2: 'Comment on egusphere-2025-5008', Uwe Ehret, 15 Dec 2025
    • AC3: 'Reply on RC2', Hamidreza Mosaffa, 17 Jan 2026
  • RC3: 'Comment on egusphere-2025-5008', Anonymous Referee #3, 23 Dec 2025
    • AC4: 'Reply on RC3', Hamidreza Mosaffa, 17 Jan 2026

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload
ED: Publish subject to minor revisions (further review by editor) (10 Feb 2026) by Yi He
AR by Hamidreza Mosaffa on behalf of the Authors (15 Feb 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Publish subject to minor revisions (review by editor) (01 Mar 2026) by Yi He
AR by Hamidreza Mosaffa on behalf of the Authors (07 Mar 2026)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (09 Mar 2026) by Yi He
AR by Hamidreza Mosaffa on behalf of the Authors (12 Mar 2026)

Journal article(s) based on this preprint

15 Apr 2026
A GNN routing module is all you need for LSTM Rainfall–Runoff models
Hamidreza Mosaffa, Florian Pappenberger, Christel Prudhomme, Matthew Chantry, Christoph Rüdiger, and Hannah Cloke
Hydrol. Earth Syst. Sci., 30, 2079–2092, https://doi.org/10.5194/hess-30-2079-2026,https://doi.org/10.5194/hess-30-2079-2026, 2026
Short summary
Hamidreza Mosaffa, Florian Pappenberger, Christel Prudhomme, Matthew Chantry, Christoph Rüdiger, and Hannah Cloke
Hamidreza Mosaffa, Florian Pappenberger, Christel Prudhomme, Matthew Chantry, Christoph Rüdiger, and Hannah Cloke

Viewed

Total article views: 4,919 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
3,287 1,511 121 4,919 64 76
  • HTML: 3,287
  • PDF: 1,511
  • XML: 121
  • Total: 4,919
  • BibTeX: 64
  • EndNote: 76
Views and downloads (calculated since 21 Oct 2025)
Cumulative views and downloads (calculated since 21 Oct 2025)

Viewed (geographical distribution)

Total article views: 4,919 (including HTML, PDF, and XML) Thereof 4,919 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 13 May 2026
Download

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
This study improves river flow prediction by combining two types of artificial intelligence models to better represent how rainfall turns into runoff and moves through river systems. Tested on the Upper Danube River Basin, the new model more accurately predicts streamflow, especially in large and connected rivers. These findings can help enhance flood forecasting and water management.
Share