The High-Impact Weather Assessment Toolkit (HIWAT) Streamflow Prediction Tool for Nepal provides 48-hour flash flood forecasts for 12,428 river segments in Nepal. The tool provides predicted estimates for flash floods from localized extreme weather phenomena like convective storms and thunderstorms. This tool complements information generated by the Streamflow Prediction Tool for Nepal 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.
The HIWAT Streamflow Prediction Tool for Nepal provides predicted estimates by routing HIWAT runoff predictions through the Routing Application for Parallel computation of Discharge (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 customized HIWAT Streamflow Prediction Tool for Nepal. It is built on Tethys, an open-source platform for water resources web app development. The Department of Hydrology and Meteorology (DHM), Government of Nepal, provided data on station locations with names. Observational data from selected stations are being used for forecast verification.
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. Find out more about HIWAT at https://tethys.servirglobal.net/apps/hiwat/
- Administrative layers of Nepal
- River network
- Province and districts
- DHM station locations with names
Users can view the following parameters upon clicking on any river stretch:
The web application displays the following layers, which can be toggled on and off:
Forecast (48-hour): Forecast information is generated from 12 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.
Download: This tab allows users to download the forecast data and ERA-Interim data as a downloadable CSV file.