Nutrient budgets for Gardens by the Bay (Singapore) water system.

G. Pijcke, K.C. Mynampati, Vladan Babovic, B. Foortse, R. Gijsman

Wednesday 1 july 2015

11:00 - 11:15h at Asia (level 0)

Themes: (T) Hydro-environment, (ST) Impacts of pollutants on the water environment

Parallel session: 9G. Environment - Impact

In July 2012, Singapore’s urban green was complemented with the opening of Gardens by the Bay, a tropical, botanic garden located at the city’s downtown Marina Bay area. A water system comprising of two ponds and a channel, surrounding the garden’s periphery, receives water from the neighbouring Marina Reservoir and the garden’s catchment. The Marina catchment has a densely urbanised nature, whereas the garden’s catchment is dominated by outside garden area in which fertilizers are applied. Both water sources contain nutrients and contribute as external loads for the Gardens by the Bay water system. Enrichment of the water system with nutrients comes at the risk of algae growth. The potential production of cyanotoxins forms a threat for ecological biodiversity and habitats, human health and algae blooms may be visually obtrusive and may cause odorous nuisance. In this context a water quality management programme is being developed for Gardens by the Bay water system. Present study focuses on the nitrogen and phosphorus budgets established for both ponds located in the gardens based on results of field monitoring and sample analysis for point-sources and sediments that have quantified the external and internal nutrient loads. Comprehensive nutrient budgets show nitrogen and phosphorus are accumulating in both ponds and give direction to water quality management strategies for the shorter and longer term for the water system.