AbstractsBiology & Animal Science

Systems management of Glenbrook Lagoon, New South Wales

by Andrew James Keogh

Institution: University of Western Sydney
Department: School of Applied and Environmental Sciences
Degree: MS(Hons)
Year: 1996
Keywords: nutrients in lagoons; Glenbrook Lagoon; catchment loading; water column; aquatic plants; surface sediment
Record ID: 1059877
Full text PDF: http://handle.uws.edu.au:8081/1959.7/423


Glenbrook Lagoon, an 8 hectare lake receiving rainfall runoff from a residential catchment, is experiencing nutrient enrichment problems expressed as excessive aquatic plant presence. This study aims to assess the relative nutrient contribution of the total system compartments, including catchment loading, water column, aquatic plants and surface sediment. This information is utilised in the formulation of management strategies which may produce a sustainable nutrient reduction and general improvement in the system. The total nutrient content of the aquatic system was determined to be high in comparison with the present nutrient loading from the catchment. The ideal management case considers nutrient reduction of the surface sediment compartment firstly, followed by the aquatic plant community, with the water column and catchment influence as relatively low priority compartments. Various strategies for managing these are proposed. The total system benefits of the ideal management case are reductions in nutrients, aquatic plant biovolume and suspended solid loading. Unavoidable constraints placed upon the ideal management case include the excessive aquatic plant presence restricting accessability to the surface sediment for dredging. The resulting best management case requires aquatic plant eradication prior to sediment management, with the total system benefits associated with the ideal management case being retained. Master of Science (Hons)