National Flood Mapping, Taiwan
- Alastair Sheppard
- Nov 16, 2022
- 2 min read
Updated: May 2
What our customers say:
“Flood Modeller's user-friendly interface provided the client with an intuitive environment for reviewing deliverables, updating models, and analysing results post-project completion. The software's productivity tools and workflows streamlined the development and updating of flood maps.”
A major US insurer required fluvial flood mapping to facilitate scientific and engineering-informed analysis of flood risk for their client's facilities in Taiwan. Using Flood Modeller, comprehensive national flood mapping was developed for the entire island (approximately 35,000 km²), enabling robust flood risk estimates, premium quotations, and the identification of appropriate risk management solutions.
Taiwan is predominantly mountainous, with extensive floodplains in the western third where the highly urbanised population is concentrated. The climate ranges from tropical to temperate, making flooding a significant natural hazard.
Due to the lack of suitable flood mapping, the project involved extensive data collection and quality assurance, the development of a Digital Terrain Model (DTM), hydrological analysis, hydraulic modelling, and flood map generation.
Overcoming data constraints was a significant challenge. A new DTM was created, incorporating linear topographic features such as embankments and channels. A rainfall-runoff modelling approach was devised, adjusting peaks to account for limited extremes data.
Key Facts
Flood map was developed for the entirety of Taiwan (approximately 35,000 km²).
Various methods were employed, including 2D-only and 1D-2D linked modelling, to accurately represent flood risk.
Flood Modeller was chosen for its suite of fast and robust 1D and 2D solvers, which could be dynamically linked.
The extensive range of structural and hydrological boundary options within Flood Modeller facilitated its use.
Flood Modeller’s open data file format and command line interface enabled the automation of model building, execution, and result analysis.
Hydraulic modelling primarily involved 2D-only modelling, but in areas with river cross-section survey data and major river structures, a dynamically linked 1D (channel) to 2D (floodplain) modelling approach was employed. Flood Modeller's extensive range of weir, sluice, orifice, and bridge types enabled accurate modelling of the impact of structures and their operation on flows and water levels.
Fluvial flood maps were developed for 1-in-100-year and 1-in-500-year flood frequency events across mainland Taiwan. All river channels with contributing watersheds greater than 10 km² were included in the modelling.
Flood Modeller's open data file format and command line interface allowed automation of the rainfall-runoff modelling, model building, running, and post-processing of hydraulic models, delivering efficiencies exceeding £200,000 for the client.
Flood Modeller's user-friendly interface provided the client with an intuitive environment for reviewing deliverables, updating models, and analysing results post-project completion. The software's productivity tools and workflows streamlined the development and updating of flood maps.
