Abstract Title
Management of cyanobacterial blooms in a shallow recreational reservoir
Start Date
24-5-2022 5:45 PM
End Date
24-5-2022 7:00 PM
Abstract
This case represents a unique opportunity to combine efforts from academia, environmental companies, and public water managers to address a case of massive cyanobacterial blooms. Foix Reservoir (NE of Spain) is a hypereutrophic and shallow (Zmax=7.5 m) reservoir where chlorophyll-a concentrations reach up to 140 µg/L, dominated by potentially toxic species such as Microcystis aeruginosa and Planktothrix agardhii. A detailed study and management proposal were developed based on a modelling effort including meteorological, physicochemical, hydrological, and biological variables and their influences on cyanobacterial blooms (field data 2009-2020), along with an in-depth review of management experiences where similar systems have been restored.
Results indicate that, besides the hypereutrophic conditions, high water temperatures and residence times enhance cyanobacterial dominance. The most cost-effective preventive measures were found to be the wastewater treatment plant upgrading, or the diversion of treated wastewater, combined with reservoir dredging. The management of Lemna to reduce the internal nutrient load and light availability is also suggested. The application of hydrogen peroxide is proposed as a mitigation measure to quickly alleviate a developing bloom. This work, which is expected to be applied in the coming years, could serve as a roadmap for water managers when facing this increasingly severe issue.
Management of cyanobacterial blooms in a shallow recreational reservoir
This case represents a unique opportunity to combine efforts from academia, environmental companies, and public water managers to address a case of massive cyanobacterial blooms. Foix Reservoir (NE of Spain) is a hypereutrophic and shallow (Zmax=7.5 m) reservoir where chlorophyll-a concentrations reach up to 140 µg/L, dominated by potentially toxic species such as Microcystis aeruginosa and Planktothrix agardhii. A detailed study and management proposal were developed based on a modelling effort including meteorological, physicochemical, hydrological, and biological variables and their influences on cyanobacterial blooms (field data 2009-2020), along with an in-depth review of management experiences where similar systems have been restored.
Results indicate that, besides the hypereutrophic conditions, high water temperatures and residence times enhance cyanobacterial dominance. The most cost-effective preventive measures were found to be the wastewater treatment plant upgrading, or the diversion of treated wastewater, combined with reservoir dredging. The management of Lemna to reduce the internal nutrient load and light availability is also suggested. The application of hydrogen peroxide is proposed as a mitigation measure to quickly alleviate a developing bloom. This work, which is expected to be applied in the coming years, could serve as a roadmap for water managers when facing this increasingly severe issue.