Demonstration experiences > Södra Bergundasjön and Norra Bergundasjön Lakes (Växjö, Sweden)
Södra Bergundasjön and
Norra Bergundasjön Lakes
(Växjö, Sweden)
Description
Södra Bergundasjön and Norra Bergundasjön lakes are located close to the city of Växjö, Sweden, with more than 70,000 inhabitants, and have for long been characterised by eutrophication problems in the form of massive blue-green algae blooms, nutrient leakage from the bottom, oxygen-depleted bottoms and in some cases fish deaths. These lakes are important recreational lakes and used by many inhabitants during summer.
Current situation
Two rounds of extensive restoration efforts (in the 1970s and 2010s) have markedly improved the nutritional status. However, for the lakes not to return to a hypertrophic state over time, additional lake restoration efforts are required. Plans for the coming decade have been decided and include reduction in fishing and completion/initiation of aluminium treatment.
The municipality of Växjö are the local stakeholder and manager of the lake. Both lakes are included in the national monitoring program as required for Water Framework Directive status assessments and sampling are performed according to Swedish national guidelines. The sampling program is more extensive (monthly between May-Oct) in these lakes in order to follow up the restoration actions. Despite the monetary effort, the number of samples and spatial coverage is low, and it will not be possible to continue on the same level in the future. The local stakeholders and manager are therefore interested in reducing on-site work and incorporate satellite monitoring together with higher spatial and temporal resolution.
Actions to be carried out within the LIFE CYANOBLOOM project
During the project, EO based methods will be applied to this site for 2 years and monthly water samples will be collected for physical-chemical laboratory analysis.
Expected results
The application of the CYANOBLOOM technology will ensure the consecution of a sustainable good condition of the lake as it will provide a time and cost-efficient alternative, avoiding the need of extensive restoration efforts to preserve its water quality. The estimated result of these efforts is that good status is achieved in Södra Bergundasjön and that Norra Bergundasjön will have a greatly improved nutritional status and good conditions to achieve a good status in the 2030s.