Beach Water Quality Forecast System

The Environmental Protection Department’s Beach Monitoring Programme relies on past water quality monitoring data in classifying the beaches according to the Beach Grading System. Although the general trends of beach water quality in the past can be revealed, the program may not fully reflect the latest water quality fluctuation arising from changes in hydrometeorological conditions at beaches. In view of this, the EPD has jointly developed a smart system with local universities to provide daily water quality forecasts for all Gazette Beach in Hong Kong, with a view to supplement the existing beach monitoring programme that relies on past monitoring data. The Beach Water Quality Forecast System is developed based on a statistical model, which takes into account the most relevant and the latest environmental and hydrometeorological parameters, such as microbiological data, rainfall, onshore wind, tide level, salinity, solar radiation and water temperature, to provide daily forecasts of beach water quality. The forecast system can more accurately capture short-term beach water quality fluctuations arising from changes in hydrometeorological conditions, acting as supplementary information for the weekly beach gradings, and hence early warnings for bathers on potential beach water quality changes.

Beach Water Quality Forecast Index

The Environmental Protection Department will use the "Beach Water Quality Forecast System" to forecast the water quality of all gazetted beaches in Hong Kong that are open for swimming.  Through predicting the E. coli level at beaches, early alert in water quality fluctuation could be achieved, and the forecast results are disseminated to the public in the form of a “Beach Water Quality Forecast Index”.

The index system is established making reference to the existing rating system for beach water quality, and is divided into four levels ranging from "1 - Good" to "4 - Very Poor". When the forecast result of a beach is “4-Very Poor”, which means that there is potential transient water quality fluctuation caused by heavy rain, and bathers should consider avoiding swimming at the beach.