Water Quality of Urban Lakes and Ponds for Recreational Use

Abstract

Background: Canberra has many lakes, ponds, and wetlands within urban areas, and water-based recreation is an integral part of its outdoor lifestyle and tourism. Poor water quality can give negative impressions and may lead to closure of swimming beaches if enterococci (faecal indicator bacterial) concentration exceeds safe levels. Evidence on how water quality impacts public health is needed to inform planning and management. Aims: This thesis consists of five studies on how recreational water quality impacts public health in Canberra. These studies explore recreational use of urban ponds and community perception of water quality; spatio-temporal variation of enterococci exceedance; and the association between hydro-meteorological parameters and enterococci in the city's three main lakes (Lake Burley Griffin, Lake Ginninderra and Lake Tuggeranong). Methods: Study 1 consisted of a systematic literature review, while Study 2 employed the System for Observing Play and Recreation in Communities for observational data. Study 3 utilised an on-site intercept survey to collect data from recreational users. Studies 4 and 5 analysed recreational water quality monitoring data from 2001 to 2023, with hydro-meteorological variables to identify associations with enterococci exceedances (> 200 colony-forming unit per 100 mL). Descriptive statistics, correlation, and multivariable regression modelling techniques were employed for data analysis. Results: The systematic literature review found that the most reported health issue was gastrointestinal illness (77.1%) while 85.7% of studies highlighted adverse health outcomes related to primary contact recreation. In observing four Canberra ponds, most participants preferred individual activities such as walking (40.84%), moderate to vigorous physical activity (37.33%) and sedentary activities (21.83%). Older users (55 years and older) perceived the water quality to be better than users aged 15 to 24 years (RR = 3.69). Water quality perceptions were lower in participants in older, established suburbs compared to newer suburbs (RR = 0.31), and in participants engaging only in walking-related recreation (RR = 0.13). Enterococci exceedances varied significantly among the three lakes and their sites. Swimming beaches in Lake Burley Griffin had a higher proportion of exceedances (13.42%) than non-swimming sites (8.98%). Weston Park East Beach, Bargang Beach, and Lake Tuggeranong Town Park Beach had significantly higher odds of exceedance compared to reference sites, with odds ratios of 1.56, 1.49, and 9.93 respectively. The odds of exceedance increased each year in Lake Ginninderra (OR 1.17) and Lake Tuggeranong (OR 1.06), with odd ratios of 1.17 and 1.06, respectively. Exceedances were higher in November (OR = 2.27) for Lake Burley Griffin, January (OR = 3.16) for Lake Ginninderra, and April (OR = 6.74) for Lake Tuggeranong. Each unit increase in rainfall, minimum daily air temperature, and water course discharge corresponded to a rise in enterococci concentration of 11.6% to 34.8%, 9.2% to 31.9%, and 17.1% to 29.8% in lake sites. Conclusions: Urban ponds in Canberra provide diverse recreational opportunities for active and healthy living with minimal illness risks. Further improvement in community perceptions of water quality could enhance these physical activities. Spatio-temporal patterns of enterococci and their association with hydro-meteorological factors inform sustainable water management and community wellbeing. Show more