Description
The Flash Flood Prediction Tool for Bangladesh provides 54-hour flash flood forecasts
for 10,049 river segments in Bangladesh. The tool provides predicted estimates for flash
floods from localised extreme weather phenomena like convective storms and
thunderstorms. It uses the precipitation forecast from the High-Impact Weather
Assessment Toolkit (HIWAT) as inputs into the Routing Application for Parallel
computatIon of Discharge (RAPID) hydrological model to estimate streamflow in the river
network. It complements information generated by the Streamflow Prediction Tool for Bangladesh and can be used as part of a decision support system for flood forecasting
services. It can assist decision makers and managers in providing flood early warnings
and response decisions during extreme events in small river catchments.
Each river segment displayed in the map interface is colour-coded daily to indicate
streamflow in the segment with respect to flood return periods.
- Blue indicates river flow <= 2-year return period
- Yellow indicates river flow > 2-year return period
- Orange indicates river flow > 10-year return period
- Red indicates river flow > 20-year return period
Users can click on a particular river segment to display forecast information. Rivers
with streamflow exceeding the threshold level for higher return periods are likely to
experience flooding.
Methodology
The Flash Flood Prediction Tool – Bangladesh provides predicted estimates by routing
HIWAT runoff predictions through the RAPID model. HIWAT combines innovative numerical
weather prediction, satellite-based precipitation, and land imagery techniques to assess
the potential threats and impacts of high-impact convective weather events. Different
proprietary and open-source GIS tools are used to generate the connections between
predicted and hindcasted runoff.
The SERVIR Hindu Kush Himalaya (SERVIR-HKH) Initiative at ICIMOD worked together with
Brigham Young University and NASA’s Marshall Space Flight Center to develop the
customised Flash Flood Prediction Tool (earlier referred to as the HIWAT Streamflow
Prediction Tool) for Bangladesh. It is built on Tethys, an open-source platform for
water resources web app development.
HIWAT runs on the SERVIR Operational Cluster Resource for Applications – Terabytes for
Earth Science (SOCRATES) platform during the pre-monsoon and monsoon season from March
to September every year.
Analytical tools
The web application displays the following layers, which can be toggled on and off:
- Outline
- District-level administrative layers of Bangladesh
- River network
Users can view the following parameters upon clicking on any river stretch displayed.
Forecast (54-hour): Forecast information is generated from nine ensemble forecasts and
shows the forecasted streamflow for a given period. The different background colours in
the graph represent the flow magnitude between defined return periods.
Users can further interact with adjoining tabs to access the following:
Historical: This tab displays a graph of simulated historical flow from 1980 onwards
based on ERA5 data.
Download: This tab allows users to download the forecast and historical data as a
downloadable CSV file.