A new forecast framework for algae bloom hazard to secure future water supply and development of tourism on Gotland

Region Gotland of Sweden experiences particuarly difficult hydrogeological conditions and limited capacity in groundwater reservoirs combined with increased demand during the warm season when it hosts tourists leading to recurring water stress.

Desalination of drinking water from the Baltic Sea is a promising alternative and two treatment plants were built to complement municipal water supply.

Their operation becomes however disturbed by intense algae blooms that coincide with summer heatwaves and the increased water demand, all predicted to intensify under the climate change.

Developing an apt forecasting system for this "multi-hazard" to inform sustainable management of Gotland´s water resources becomes thus a priority and is of broader relevance to other coastal services and other regions in Sweden.The aim of our four-year project is to develop a novel forecast framework for hazard (algae blooms due to heatwaves) as well as hazard impact (on water resource management) on short term (early warning) and long term (climate scenarios).

New Lagrangian modelling tools and improved biogeochemical models will be developed at the Stockholm University and embedded in existing operational services for weather and ocean state at the Swedish Meteorological and Hydrological Institute.

Our stakeholders (Region Gotlands VA-Avdeling, Blått Centrum Gotland) will provide input on adverse impacts, information required for management, and feedback on the forecast framework during the project.