scholarly journals Predicting ‘very poor’ beach water quality gradings using classification tree

2015 ◽  
Vol 14 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Wai Thoe ◽  
King Wah Choi ◽  
Joseph Hun-wei Lee
Keyword(s):  
Water Quality ◽  
Hong Kong ◽  
Linear Models ◽  
Classification Tree ◽  
Classification Trees ◽  
Water Quality Prediction ◽  
E Coli ◽  
Poor Water Quality ◽  
Beach Water Quality ◽  
Beach Water

A beach water quality prediction system has been developed in Hong Kong using multiple linear regression (MLR) models. However, linear models are found to be weak at capturing the infrequent ‘very poor’ water quality occasions when Escherichia coli (E. coli) concentration exceeds 610 counts/100 mL. This study uses a classification tree to increase the accuracy in predicting the ‘very poor’ water quality events at three Hong Kong beaches affected either by non-point source or point source pollution. Binary-output classification trees (to predict whether E. coli concentration exceeds 610 counts/100 mL) are developed over the periods before and after the implementation of the Harbour Area Treatment Scheme, when systematic changes in water quality were observed. Results show that classification trees can capture more ‘very poor’ events in both periods when compared to the corresponding linear models, with an increase in correct positives by an average of 20%. Classification trees are also developed at two beaches to predict the four-category Beach Water Quality Indices. They perform worse than the binary tree and give excessive false alarms of ‘very poor’ events. Finally, a combined modelling approach using both MLR model and classification tree is proposed to enhance the beach water quality prediction system for Hong Kong.

Epidemiological Study of Beach Water Pollution and Health-Related Bathing Water Standards in Hong Kong

1991 ◽  
Vol 23 (1-3) ◽  
pp. 243-252 ◽  
Author(s):  
W. H. S. Cheung ◽  
R. P. S. Hung ◽  
K. C. K. Chang ◽  
J. W. L. Kleevens
Keyword(s):  
Water Quality ◽  
Hong Kong ◽  
Epidemiological Study ◽  
Risk Levels ◽  
E Coli ◽  
Increased Risk ◽  
Health Related ◽  
Acceptability Criterion ◽  
Beach Water Quality ◽  
Beach Water

A prospective epidemiological study was undertaken in Hong Kong in 1987, in which 18,741 usable responses were obtained. It showed bathing in the coastal beaches of Hong Kong poses an increased risk of developing gastrointestinal, ear, eye, skin, respiratory and total illness. Swimmers immersed in the more polluted beach waters are exposed to a significantly higher risk of contracting swimming-associated gastrointestinal, skin, respiratory and total illness. E. coli was found to be the best indicator for swimming-associated gastroenteritis and skin symptoms amongst the bathers, and a linear relationship could be established. Staphylococci was a good indicator for ear, respiratory and total illness, and should be used in complementary to E. coli. Beach water quality objectives for both E. coli and staphylococci have been proposed. A 4-tier classification system (rather than a single acceptability criterion) based on swimming-associated health risks has been developed for the beaches of Hong Kong. Information on the bacterial water quality and health risk levels of individual beaches is reported to the public both annually and fortnightly, so that beach-goers can choose where to go for swimming based on health effects data.

scholarly journals Waterborne illness and injury: a feasibility study of a site-specific predictive model for beach water quality at Beachway Park in the City of Burlington

2021 ◽  
Author(s):  
Ramien Sereshk
Keyword(s):  
Water Quality ◽  
Predictive Model ◽  
Real Time ◽  
Site Specific ◽  
E Coli ◽  
Time Basis ◽  
A Site ◽  
Persistence Model ◽  
Beach Water Quality ◽  
Beach Water

It is commonly assumed that the persistence model, using day-old monitoring results, will provide accurate estimates of real-time bacteriological concentrations in beach water. However, the persistence model frequently provides incorrect results. This study: 1. develops a site-specific predictive model, based on factors significantly influencing water quality at Beachway Park; 2. determines the feasibility of the site-specific predictive model for use in accurately predicting near real-time E. coli levels. A site-specific predictive model, developed for Beachway Park, was evaluated and the results were compared to the persistence model. This critical performance evaluation helped to identify the inherent inaccuracy of the persistence model for Beachway Park, which renders it an unacceptable approach for safeguarding public health from recreational water-borne illnesses. The persistence model, supplemented with a site-specific predictive model, is recommended as a feasible method to accurately predict bacterial levels in water on a near real-time basis.

Daily prediction of marine beach water quality in Hong Kong

2012 ◽  
Vol 6 (3) ◽  
pp. 164-180 ◽  
Author(s):  
W. Thoe ◽  
S.H.C. Wong ◽  
K.W. Choi ◽  
J.H.W. Lee
Keyword(s):  
Water Quality ◽  
Hong Kong ◽  
Beach Water Quality ◽  
Beach Water

scholarly journals Waterborne illness and injury: a feasibility study of a site-specific predictive model for beach water quality at Beachway Park in the City of Burlington

2021 ◽  
Author(s):  
Ramien Sereshk
Keyword(s):  
Water Quality ◽  
Predictive Model ◽  
Real Time ◽  
Site Specific ◽  
E Coli ◽  
Time Basis ◽  
A Site ◽  
Persistence Model ◽  
Beach Water Quality ◽  
Beach Water

It is commonly assumed that the persistence model, using day-old monitoring results, will provide accurate estimates of real-time bacteriological concentrations in beach water. However, the persistence model frequently provides incorrect results. This study: 1. develops a site-specific predictive model, based on factors significantly influencing water quality at Beachway Park; 2. determines the feasibility of the site-specific predictive model for use in accurately predicting near real-time E. coli levels. A site-specific predictive model, developed for Beachway Park, was evaluated and the results were compared to the persistence model. This critical performance evaluation helped to identify the inherent inaccuracy of the persistence model for Beachway Park, which renders it an unacceptable approach for safeguarding public health from recreational water-borne illnesses. The persistence model, supplemented with a site-specific predictive model, is recommended as a feasible method to accurately predict bacterial levels in water on a near real-time basis.

Real-time forecasting of Hong Kong beach water quality by 3D deterministic model

2013 ◽  
Vol 47 (4) ◽  
pp. 1631-1647 ◽  
Author(s):  
S.N. Chan ◽  
W. Thoe ◽  
J.H.W. Lee
Keyword(s):  
Water Quality ◽  
Hong Kong ◽  
Real Time ◽  
Deterministic Model ◽  
Beach Water Quality ◽  
Beach Water
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