Streamflow Prediction Tool – Bhutan

The Streamflow Prediction Tool for Bhutan provides 10-day streamflow predicted estimates for 119 river segments in Bhutan; Each river segment displayed in the map is assigned a unique identifier. Users can click on a particular river segment to display 10-day streamflow forecasts for the river stretch. This tool can be used as part of the decision support system for flood forecasting services and can assist decision makers and managers to provide flood early warnings and response during extreme events.

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

Rivers with streamflow exceeding the threshold for higher return periods are likely to experience flooding.


The Streamflow Prediction Tool provides predicted estimates by using runoff predictions from the European Center for Medium Range Weather Forecasts (ECMWF) routed through the Routing Application for Parallel Computation of Discharge (RAPID) model. The connection between the predicted and hind-casted runoffs is generated using different proprietary and open-source GIS tools.

The SERVIR Hindu Kush Himalaya (SERVIR-HKH) Initiative at ICIMOD worked together with Brigham Young University to develop a customized Streamflow Prediction Tool for Bhutan. The tool is built on Tethys, an open-source framework for developing web-based applications for Earth observation.

Analytical tools

The web application displays the following layers, which can be toggled on and off:

  • Administrative layers of Bhutan
  • Country outline
  • River network
  • Different districts (Dzongkhags)

Users can view the following parameters upon clicking on any river stretch:

Bhutan Data

Forecast (10-day): Forecast information is generated from 52 ensemble forecasts and shows the average, upper, and lower standard deviations; the maximum and minimum flows; and a single higher resolution forecast (black line). The references can be seen on the right, and the different layers can be turned on and off. The different background colours in the graph represent the flow magnitude between defined return periods.

User can further interact with adjoining tabs to access the following:
Historical: This tab displays a graph of simulated historical flows from 1980.
Flow-duration: This tab shows information on flow reliability.
Download: This tab allows users to download the forecast data and ERA-Interim data as a downloadable CSV file.

Explore the tool