The NEPTUNE-OMS (OMS) is a Delft-FEWS application used for monitoring and forecasting hydrodynamics and water quality in the Singapore coastal waters. Data is imported from eight buoys around the island measuring water quality parameters such as: chlorophyll, nitrates, phosphates, and dissolved oxygen; as well as temperature, salinity, and wind speed/direction.

Who uses NEPTUNE-OMS, and for what purpose?

The OMS is used by the water quality modelling team of the Singapore National Environment Agency. The key concerns of NEA include maintaining good coastal water quality for recreation (beaches) and fisheries (including aquaculture) as well as providing advice on the spread of contaminants during (oil) spill incidents. The OMS allows the operators to easily visualize, process, and interpret real time buoy data in combination with forecasts and use this information to send warnings and produce reports about coastal water quality.

Who is involved in managing, developing, and financing the system?

NEPTUNE-OMS is financed and used by the National Environment Agency (NEA) in Singapore. NUSDeltares, a cooperation between the National University of Singapore (NUS) and Deltares, set up Neptune-OMS for NEA between 2011 and 2013. Since then, it has been running at the Singaporean government computational premises. Deltares and the HydroInformatics Institute (H2i) continue to develop and maintain the system and provide support.

What are the main components?

The OMS is centered around eight monitoring buoys, which provide real time high frequency water quality measurements for the coastal waters around Singapore. The buoy data are visualized in the OMS client and automatically analyzed for anomalies. OMS performs monthly checks for buoy drift. OMS automatically generates warnings when values exceed certain threshold values.

OMS also runs a forecast modelling chain consisting of two hydrological Wflow models, for Singapore and Malaysia, which provide river discharges to a hydrodynamic Delft3D-4 model. The hydrodynamic results of the Delft3D-4 model are subsequently used to run a Delft3D-WAQ water quality model. The forecasts have a length of 2 days and are run twice a day.

In case of an oil spill incident, the operators can analyze various scenarios by running a Delft3D-PART oil spill model from the client. The oil spill model can be run for the past 10 days and up to 2 days into the future. There is also an option to run a passive tracer particle tracking simulation for the forecast length and to perform a backtracking calculation. 

Particle tracking and oil spill modelling

The oil spill functionality in Delft-FEWS has recently been updated to allow for better representation of oil spills in real-time, and to provide a more user-friendly method of starting simulations.

OMS operators can now select from four types of spills: instantaneous point spill, instantaneous patch spill, continuous point spill, and continuous point + radius spill. For each type of spill, five oil classes have been configured from which the user can choose, ranging from non-persistent light oils (such as gasoline) to heavy crude oils (such as Bunker C fuel oil). There even is an option to allow the oil to settle as a result of increased density due to the uptake of sediments.

Each class of oils is represented by a typical oil type from that class, with its own specific density, kinematic viscosity, evaporation rate, and dispersion parameters.

The operators can start a new simulation directly from the Spatial Display, where they draw a point or polygon on the map to indicate the location of the spill or oil patch. They can then provide additional spill characteristics, such as the time of spill, oil type, mass/rate of spill, and the number of particles, before running the model.

The simulations are run on the server, so it is possible to start multiple simulations at the same time. The results can be visualized in the spatial displays and can be loaded into dashboards to quickly compare the results of various simulations.

What’s next for NEPTUNE-OMS?

In the coming years the system will be updated and improved further. The models are currently being re-calibrated. These new models, which use the latest software versions, will maintain the quality of the system.