Eutrophication Modeling of Singapore Waters
Current research and development on the Eutrophication Modelling of Singapore Waters covers the following aspects:
Utilisation of 3-D eutrophication model NEUTRO to predict the water quality
A 3-D eutrophication model (NEUTRO) is under development in PORL since 1997. It consists of 3-D transport, WASP kinetics (Original WASP (US EPA) model is 0-D) and Silica cycles. NEUTRO takes into consideration tidal forcing, advection, diffusion and settling of the admixture and suspended particles, as well as chemical and physical kinetic reactions of the diluted and suspended substances. It was applied to Singapore coastal waters within several commercial and research projects for environment impact assessment as well as water quality management around Singapore Island.
Scientific Focus
- To understand observed features of nutrient dynamics in Singapore seawaters
- To predict nearest (hour scale) and remote future (decades) of the coastal environment
- To study possible reasons of algal bloom outbreaks by means of scenario analysis
Capabilities
- Computation of 4-D (time & space) dynamics of nutrients, phytoplankton, and oxygen in Singapore Strait
- Impact assessment of industrial developments and anthropogenic spills in coastal zones
- Consequences of acute and chronic near-shore spills on water quality parameters
- Forecast long-term and hindcast of short-term consequences of development in coastal zone on marine environment
- Prediction of algal blooms outbreaks
To date, much effort has been made by the team to achieve baseline concentration and to reproduce correctly general features and observed fine patterns in the water column of Singapore seawater.
Description of NEUTRO model
- The Eutrophication model (NEUTRO) predicts water quality with respect to nutrients, plankton and dissolved oxygen, suspended solids as well as bacteria decay.
- Seven interacting Systems (Cycles) are included with benthic coupling for dissolved oxygen and nutrients: Nitrogen, Phosphorus, Carbon and Silica cycles; Phytoplankton and Zooplankton Dynamics; and Dissolved Oxygen Balance.
- The total of 13 state variables are considered: Ammonia Nitrogen (NH3), Nitrate Nitrogen (NO3), Phosphate (PO4), Phytoplankton, Carbonaceous Biochemical Oxygen Demand (CBOD), Dissolve Oxygen (DO), Organic Nitrogen (ON), Organic Phosphorus (OP), Zooplankton, Bacteria, Total Solids (TSS), Available Dissolved Silica (Si(OH)4) and Particulate Biogenic Silica (SiO2).
Schematic of interactions between nutrients, plankton and the dissolved oxygen balance
Baselines concentration of model parameters by statistical analysis
The baseline values are those, which presumably are not affected by local sources of pollutants. An exploratory data analysis is done to identify the outliers in the dataset from the field measurements and the data are analyzed statistically to find the mean baseline value of model parameters by ANOM (Analysis of Mean) using a statistical software MINITAB-V14. The obtained baseline value is set as initial conditions for NEUTRO parameters.
Simulation of NEUTRO result
NEUTRO model is developed to simulate 3-D eutrophication processes in the water column of Singapore coast. Results show that the model is able to reproduce the characteristics of water. NEUTRO model is simulating right period and right pattern in the water column of Singapore coast.
Model results for baseline concentration simulation at a monitoring station on the south coast of Singapore:
Environmental Impact Assessment using NEUTRO
- Use baseline as initial conditions.
- Use fine-tuned coefficients for chemical kinetics.
- Specify existing and expected (as the result of industrial development) sources of nutrient flux.
- Compute for different hydrodynamic and nutrient load scenarios until quasi-steady-state patterns are obtained.
- Analyze and visualize the model output results to depict the temporal and spatial dynamics of each parameters.
