Mitigating the effects of high biomass algal blooms on the drinking water intakes of the city of Buenos Aires, Argentina

ABSTRACT

Three-dimensional hydrodynamic and ecological modelling was used to explore strategies to mitigate the impacts of high biomass algal blooms (Aulacoseira sp.) on the drinking water intakes of the city of Buenos Aires, in the Río de la Plata. An automated real-time and a four-day forecast warning system was implemented in 2010 in order to predict the occurrence of such blooms near the intakes. Since the adoption of the technology, blooms of Aulacoseira sp. were neither predicted nor observed, demonstrating that the system did not create a false positive. Further, a historical high biomass bloom event was successfully predicted and then used to test two engineering solutions, designed to mitigate the impact of strong blooms. It was found that extending the raw drinking water intakes offshore beyond the high algae concentration provided a 50% reduction in Aulacoseira sp. concentrations. Alternatively, placing groynes around the intake sites induced a dilution of the phytoplankton patch and reduced the concentrations by 40%.

Keywords:

• Estuaries
• hydraulic structure design and management
• mitigating bloom effects
• mixing enhancement
• real-time modelling
• three-dimensional models
• water quality

Acknowledgements

We would like to thank the supporting team of fieldwork and real-time and forecast system, developed at the Centre for Water Research – Greg Attwater, Lee Goodyear Roger Head, Carol Lam, and Angus Stuart, and Dr Christopher Dallimore from Hydronumerics Pty Ltd. The input of Dr Ryan Alexander is also acknowledged. We are also grateful for the support provided by Dr Gabriel Raggio and Dr Fabian Lopez regarding logistics and data collection, and all the institutions that contributed with data for this study – Aguas y Saneamientos Argentinos (AySA) and particularly Maria de la Paz Vilas, Servicio de Hidrografia Naval – Argentina (SHN), Servicio Meteorológico Nacional – Argentina (SMN), Subsecretaria de Puertos y Vias Navegables – Argentina (SPVN), and Compañía Administradora del Mercado Mayorista Eléctrico Sociedad Anónima (CAMMESA). The findings presented herein are those of the authors and do not represent the views or opinions of AySA. This article represents Centre for Water Research reference 2352-CS.

Funding

The first author is a recipient of the Scholarship for International Research Fees from the University of Western Australia and Centre for Water Research ad hoc Scholarship.