Enhancing Flood Early Warning Services in the Hindu Kush Himalaya Region

SERVIR HKH, with the technical support of Brigham Young University (BYU) developed a Streamflow Prediction Tool (SPT) based on the European Centre for Medium-Range Weather Forecasts (ECMWF) ensemble forecasting. The system incorporates all primary and secondary rivers in the HKH region. The system provides user-friendly access to 10-day forecasts of streamflow. Based on the regional system, a customized web interface was developed to meet the needs of respective users in Nepal, Bhutan, and Bangladesh. For the Flood Forecasting & Warning Centre (FFWC) in Bangladesh, an interface was developed to provide prediction at transboundary rivers. Using the precipitation forecast from the High-Impact Weather Assessment Toolkit (HIWAT), a streamflow forecasting system was developed to support flash flood early warning in small local rivers in Bangladesh and Nepal. This system provides a lead time of 54 hours. We are also developing a mobile app to reach at a community level. The Enhancing Flood Early Warning service developed two products during phase 2.

• Streamflow Prediction Tool (SPT) for riverine flood early warning
• Flash Flood Prediction Tool (FFPT) for smaller rivers

Note that the service has been completed but periodic updates are made as needed by end users.

Rationale

Early warning is one of the critical elements for building the resilience of vulnerable communities against flooding. Early warning systems (EWS) are often deficient in delivering actionable information in both lead time and content. Existing in situ station-based flood EWS are challenged by short lead times and being hazard-based early warning leading to inadequate response times and insufficient information about the scale of potential impact. In Bangladesh, the hydrological models for flood early warning suffer from a lack of upstream data, making it difficult to increase lead time of flood forecasting downstream. In Nepal, flood forecasting for smaller rivers is a challenge due to its geography and lack of in situ data. Longer lead times and access to critical information ensures improved preparedness for responders, in turn, saving more lives and property. Disseminating warning information and giving communities timely access, is also important to get a maximum return from investing in early warning services.