Putrajaya Lake and Wetlands being the centrepiece of Malaysia's administrative city is an important destination for recreation, sports and tourism in the country. The urban water body system with a total surface area of 400 hectares was designed and built so as to encircle the core island creating a complex morphometry. To ensure the water quality remains in its highest-level condition since its beginning, to perform its multi-functional uses, managing the lake catchment is of paramount importance. This paper describes the application of numerical simulation of Putrajaya Lake using coupled three-dimensional hydrodynamic-ecosystem model to assess the spatial dynamics of the lake water quality. The hydrodynamic model simulates the flow pattern under different meteorological forcing variables. The ecosystem model simulates the resulting spatial and diurnal water quality pattern. Wind is the dominant forcing variable driving the flow field. The lake exhibits spatial variation of physico-chemical variables with an overall high-quality of surface water. The model simulation illustrates the impact of potential discharges on the lake water quality, such as spread of pollutants, subsequently provides a useful tool to enhance the management of the lake sustainably under changing environment.

Abstract. This study is concerning phosphorus distribution in Putrajaya Wetland. Phosphorus is one of the important component in nutrients for living things be it aquatic or non -aquatic organisms. Total phosphorus (TP) results will give some information on the trophic status of surface water in water bodies. The focus of this study is to determine the total phosphorus concentration in Putrajaya Wetland which is in the inlet of the wetland then outlet of the wetland (Central Wetland Lake). The water sample is taken from Putrajaya Wetland and the test was conducted in the laboratory. The result from this study shows the results for total phosphorus according to month, sampling station and cells. Lowest total phosphate at the Central Wetland compare with all the wetland arms cells.

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