Work package 3

Case studies

There are a number of potential applications of high-resolution precipitation forecasts. This project will be carried out in close collaboration with a number of end-users for various selected applications that are all directly affected by intense rainfall.

The intention is to carry out actual model testing using forecasts from the developed system, but in some applications the evaluation will likely be of more qualitative nature based on discussions with end-users.

The case studies will have two main objectives:

(1) to assess the added value of the new high-resolution forecasts compared to today’s available forecasts and;

(2) to influence the design of the forecast tailoring. Hence, WP3 feeds back into both WP1 and WP2.

The evaluation of the case studies will mainly be conducted in so-called ‘hindcast mode’, i.e. using old forecasts, but at a later stage it will be attempted to test the forecasts operationally in real-time.

 The following applications are intended:

• Urban hydrology: Short-term rainfall forecasts can be used for controlling flows in real-time and reducing risk of flooding in sewers and urban areas. The project has no resources for this type of evaluation, but it is intended to be performed in a coupled study. A preliminary study object is river Mölndalsån for which SMHI has contributed to a hydrological forecasting model.

• Debris flows in steep terrain: Intense rainfall can initiate debris flow when conditions regarding slope, soil type, and water saturation are satisfied. The potential use of high-resolution forecasts will be examined in the town Åre with surroundings. This is an area where several severe debris flows have caused significant damage on buildings and infrastructure during the latest Decennium. We will examine how a warning system may be implemented and perform a cost-benefit analysis of alternative approaches.

• Hydropower production: High-resolution forecasts are potentially useful for regulation of hydroelectric dams, especially at the onset of spring flood. Additionally, there is a use regarding real-time management of run-of-the-river (ROR) plants with little or no reservoir capacity. Assessment will be made for a number of Swedish hydropower producing rivers.

MSB timetable