Dolojan et al. (2026) Quantifying the impact of landform modifications on flood hazards and exposure: Event-based numerical simulations using reconstructed historical terrain

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2026
• Date: 2026-09-14
• Authors: Nilo Lemuel J. Dolojan, Reika Nomura, Kenjiro Terada, Daisuke Sugawara, Atsushi Kawauchi, Yuichi Ebina, Atsushi Suzuki, Atsuko MIZOGUCHI, Yukiyasu Fujii, Takeshi Kodaka, Shuji Moriguchi
• DOI: 10.1016/j.ejrh.2026.103946

Research Groups

• International Research Institute of Disaster Science, Tohoku University
• Department of Civil and Environmental Engineering, Tohoku University
• Department of Civil Engineering, Faculty of Science and Technology, Meijo University

Short Summary

This study evaluates the impact of historical landform modifications on flood hazards and exposure in Marumori Town, Japan. A high-resolution hydrologic model simulated 35 actual rainfall events on both a reconstructed historical (1908) terrain and the present engineered landscape.

Objective

• Quantify how anthropogenic landform alterations influence hazard exposure

Study Configuration

• Spatial Scale: Localized catchment basin with an area of approximately 273.46 km2
• Temporal Scale: Simulations were conducted for 35 actual recorded rainfall events spanning from 1994 to 2024

Methodology and Data

• Models used: Hydrologic-geotechnical model proposed by Dolojan et al. (2023)
• Data sources: Hourly precipitation gauge data, water level hydrographs, Digital Elevation Models (DEMs), soil information, road networks, building footprints, and historical topographic maps

Main Results

• The engineered present-day terrain mitigated inundation volumes more effectively during high-intensity events than during low-intensity ones.
• The average reduction in flood metrics across all primary flood metrics was observed when comparing the past to the present terrains.
• A 7.1% relative decline in peak inundation volume (𝑉𝑝𝑒𝑎𝑘) and a 2.6% decrease in maximum inundated area (𝐴𝑚𝑎𝑥) were observed.

Contributions

• This study provides critical insights into the functional limits of engineered terrains compared to historical floodplains.
• The research highlights the importance of considering rainfall characteristics when evaluating the impact of landform modifications on hazard exposure.

Funding

• This research was funded by the Japan Society for the Promotion of Science (JSPS) under grant numbers [insert grant numbers].

Citation

@article{Dolojan2026Quantifying,
  author = {Dolojan, Nilo Lemuel J. and Nomura, Reika and Terada, Kenjiro and Sugawara, Daisuke and Kawauchi, Atsushi and Ebina, Yuichi and Suzuki, Atsushi and MIZOGUCHI, Atsuko and Fujii, Yukiyasu and Kodaka, Takeshi and Moriguchi, Shuji},
  title = {Quantifying the impact of landform modifications on flood hazards and exposure: Event-based numerical simulations using reconstructed historical terrain},
  journal = {Journal of Hydrology Regional Studies},
  year = {2026},
  doi = {10.1016/j.ejrh.2026.103946},
  url = {https://doi.org/10.1016/j.ejrh.2026.103946}
}