Assessing the Effectiveness of Nature‐Based Solutions and Building‐Level Flood Risk Reduction Measures: An Open‐Source Coupled Model

21382 6 113104 2 341626 document 113104 Water Resources Research - 2026 - Bril - Assessing the Effectiveness of Nature‐Based Solutions and Building‐Level Flood.pdf application/pdf ea44525b6cd753a5b59b93ad3465e4b4 MD5 2744827 2026-03-16 10:28:54 https://pure.iiasa.ac.at/id/eprint/21382/1/Water%20Resources%20Research%20-%202026%20-%20Bril%20-%20Assessing%20the%20Effectiveness%20of%20Nature%E2%80%90Based%20Solutions%20and%20Building%E2%80%90Level%20Flood.pdf 21382 1 1 application/pdf text en public cc_by_4

Water Resources Research - 2026 - Bril - Assessing the Effectiveness of Nature‐Based Solutions and Building‐Level Flood.pdf

published 113105 2 341632 document 113105 lightbox.jpg image/png 75ee8e1fb2d66ec65ff575ff88708d5a MD5 73488 2026-03-16 10:39:04 https://pure.iiasa.ac.at/id/eprint/21382/2/lightbox.jpg 21382 2 2 image/png other Thumbnails conversion from text to thumbnail_lightbox en public

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http://eprints.org/relation/isVersionOf https://pure.iiasa.ac.at/id/document/113104 http://eprints.org/relation/isVolatileVersionOf https://pure.iiasa.ac.at/id/document/113104 http://eprints.org/relation/isIndexCodesVersionOf https://pure.iiasa.ac.at/id/document/113104 archive 353 disk0/00/02/13/82 2026-03-16 10:30:36 2026-03-16 10:30:36 2026-03-16 10:30:36 article show Bril V.C. de Bruijn J. 8884 0000-0003-3961-6382 de Moel H. Sadana T. Busker T. Botzen W.J.W. Aerts J.C.J.H. Assessing the Effectiveness of Nature‐Based Solutions and Building‐Level Flood Risk Reduction Measures: An Open‐Source Coupled Model pub BNR WAT Floods are expected to increase in frequency and severity due to climate change. Recent floods have shown that many catchments worldwide are vulnerable to floods, highlighting the need for additional adaptation measures. This study extends the Geographical, Environmental, and Behavioral (GEB) model by coupling it to a hydrodynamic and a flood risk model to assess the effects of dry-proofing, wet-proofing, retention ponds, reforestation, and the creation of natural grassland. A key innovation is the integration of all local-scale models, thereby allowing for a catchment-wide assessment of the impacts of various measures on interlinked hydrological conditions, flood extents and depths, damages, and risk. We apply our method to the Geul catchment (shared between the Netherlands, Belgium and Germany), which was heavily flooded in July 2021. Our results show that reforestation and creation of natural grassland (both 10 km2) reduce flood extent by 12% and average water depth by 10%. Damage is decreased up to 38%. Larger retention ponds (1 m deeper) have a much smaller reduction in flood extent (3%), depth (0.5%) and damage (1.6%), due to limited storage capacity compared to excess rainfall. The building-level adaptation scenarios outperform all nature-based solutions, with dry-proofing reducing more damage (up to 95%) than wet-proofing (around 55%). A cost-benefit analysis shows that several adaptation measures are economically attractive. Overall, our findings show a coupled model is essential for comparing the relative effectiveness of different flood adaptation measures and supporting informed risk management decisions. The open-source model is transferable to other catchments worldwide to guide decision-making. 2026-03-03 published American Geophysical Union doi:10.1029/2025WR041436 3164 public Water Resources Research 62 3 e2025WR041436 TRUE 00431397 info:eu-repo/semantics/article