Spatial analysis of urban stormwater quality

Urban stormwater non-point source pollutants are recognized as a major cause of receiving waters quality deterioration. To date most research has focused on specifying temporal variations of stormwater quality parameters which includes high uncertainties and also increases the risk of pollution control structures failure. Traditionally, the temporal variations of quality parameters in forms of either pollutograph or Event Mean Concentration (EMC) is obtained by sampling stormwater at the outlet of urban catchments for quality analysis in addition to measurement of flow rate over years. Spatial variations of the runoff quality are the key factor in non-point source pollution studies. This research investigates spatial variability of urban runoff quality parameters such as Total Phosphorous (TP), Total Nitrogen (TN), Suspended Solids (SS) and Biochemical Oxygen Demands (BOD) in relation to land use of urban catchments. In spatial analysis, stormwater will be sampled over the whole catchment area for a number of rainfall events during a year without any requirement to measure flow rate. This research showed comparable results for average pollutant concentrations with those of other urban catchments in Australia where traditional sampling method was used. The research outcomes will reliably estimate pollutants concentration for improved and efficient design of pollution control structures for each land use.

Regional and urban Victorian diabetic youth: clinical and quality-of-life outcomes

Objectives: To compare groups of urban and regional Victorian diabetic children and assess their quality of life, diabetes knowledge, access to services and metabolic control.

Methods: Forty-seven children from three regional Victorian communities (Horsham, Warrnambool and Sale; n = 16, 18 and 13, respectively) were compared with 120 age-, sex- and duration of diabetes-matched children attending the Royal Children's Hospital (RCH) diabetes clinic in Melbourne. Quality of life, diabetes knowledge, use of services, and metabolic control were assessed using the child health questionnaire (CHQ PF-50/CF-80); a diabetes-knowledge questionnaire; access to a diabetes nurse educator (DNE), dietitian and complication screening; and indices of mean HbA1C (values are taken every 3 months in the 'yearly HbA1C'), respectively.

Results: Comparisons of CHQ data showed that regional diabetic youth scored significantly lower on most subscales. The greatest deficits were seen in areas of mental health, self-esteem, parent impact (emotional) and family cohesion. Diabetes knowledge and median yearly HbA1C for patients were not significantly different between the regional and urban centres (8.1%, 8.9%, 8.4% and 8.6% at RCH, Horsham, Warrnambool and Sale, respectively). Patients in regional centres had reportedly less access to team-based diabetes care.

Conclusions: Regional youth in Victoria, with similar levels of metabolic control and diabetes knowledge as their urban counterparts, have a markedly lower quality of life, implying a negative synergy between diabetes and the demands of regional lifestyles.

Optimal sensor placement and measurement of wind for water quality studies in urban reservoirs

We collaborate with environmental scientists to study the hydrodynamics and water quality in an urban district, where the surface wind distribution is an essential input but undergoes high spatial and temporal variations due to the complex urban landform created by surrounding buildings. In this work, we study an optimal sensor placement scheme to measure the wind distribution over a large urban reservoir with a limited number of wind sensors. Unlike existing sensor placement solutions that assume Gaussian process of target phenomena, this study measures the wind which inherently exhibits strong non-Gaussian yearly distribution. By leveraging the local monsoon characteristics of wind, we segment a year into different monsoon seasons which follow a unique distribution respectively. We also use computational fluid dynamics to learn the spatial correlation of wind in the presence of surrounding buildings. The output of sensor placement is a set of the most informative locations to deploy the wind sensors, based on the readings of which we can accurately predict the wind over the entire reservoir surface in real time. 10 wind sensors are finally deployed around or on the water surface of an urban reservoir. The in-field measurement results of more than 3 months suggest that the proposed sensor placement and spatial prediction approach provides accurate wind measurement which outperforms the state-of-the-art Gaussian model based or interpolation based approaches.

Demo abstract: wind measurements for water quality studies in urban reservoirs

Water quality monitoring and prediction are critical for ensuring the sustainability of water resources which are essential for social security, especially for countries with limited land like Singapore. For example, the Singapore government identified water as a new growth sector and committed in 2006 to invest S$ 330 million over the following five years for water research and development [1]. To investigate the water quality evolution numerically, some key water quality parameters at several discrete locations in the reservoir (e.g., dissolved oxygen, chlorophyll, and temperature) and some environmental parameters (e.g., the wind distribution above water surface, air temperature and precipitation) are used as inputs to a three-dimensional hydrodynamics-ecological model, Estuary Lake and Coastal Ocean Model - Computational Aquatic Ecosystem Dynamics Model (ELCOM-CAEDYM) [2]. Based on the calculation in the model, we can obtain the distribution of water quality in the whole reservoir. We can also study the effect of different environmental parameters on the water quality evolution, and finally predict the water quality of the reservoir with a time step of 30 seconds. In this demo, we introduce our data collection system which enables water quality studies with real-time sensor data.

Sensor placement and measurement of wind for water quality studies in urban reservoirs

We study the water quality in an urban district, where the surface wind distribution is an essential input but undergoes high spatial and temporal variations due to the impact of surrounding buildings. In this work, we develop an optimal sensor placement scheme to measure the wind distribution over a large urban reservoir using a limited number of wind sensors. Unlike existing solutions that assume Gaussian process of target phenomena, this study measures the wind that inherently exhibits strong non-Gaussian yearly distribution. By leveraging the local monsoon characteristics of wind, we segment a year into different monsoon seasons that follow a unique distribution respectively. We also use computational fluid dynamics to learn the spatial correlation of wind. The output of sensor placement is a set of the most informative locations to deploy the wind sensors, based on the readings of which we can accurately predict the wind over the entire reservoir in real time. Ten wind sensors are deployed. The in-field measurement results of more than 3 months suggest that the proposed sensor placement and spatial prediction scheme provides accurate wind measurement that outperforms the state-of-the-art Gaussian model based on interpolation-based approaches.

Human residential status and habitat quality affect the likelihood but not the success of lapwing breeding in an urban matrix

Wildlife living in the suburbs faces the challenge of dealing with human presence and yard management (including the occurrence of pets) which vary at the scale of the house block. This study examined the influence of ecological factors (e.g. extent of grass and food availability) and anthropogenic factors (e.g. human activity and garden usage) on breeding site choice and reproductive success of the ground-nesting masked lapwing Vanellus miles on Phillip Island, Australia. Lapwings nested less frequently in residential properties (high levels of human usage) compared with vacant blocks and holiday houses. They were also more likely to breed on properties with high food availability and larger areas of grass. None of these variables influenced clutch size or the probability of eggs hatching, although larger clutches and higher hatching rates tended to be associated with more food. This study shows that, for an urban exploiting species, habitat quality is not homogenous at the scale of the house block, and that human activity is avoided by a species generally considered highly tolerant of people.

The association between self-reported diet quality and health-related quality of life in rural and urban Australian adolescents

OBJECTIVE: This study examines the relationship between diet quality and health-related quality of life (HRQoL) in rural and urban Australian adolescents, and gender differences.

DESIGN: Cross-sectional.

SETTING: Secondary schools.

PARTICIPANTS: 722 rural and 422 urban students from 19 secondary schools.

MAIN OUTCOME MEASURES: Self-report dietary-related behaviours, demographic information, HRQoL (AQoL-6D) were collected. Healthy and unhealthy diet quality scores were calculated; multiple linear regression investigated associations between diet quality and HRQoL.

RESULTS: Compared to urban students, rural students had higher HRQoL, higher healthy diet score, lower unhealthy diet score, consumed less soft drink and less frequently, less takeaway and a higher proportion consumed breakfast (P < 0.05). Overall, males had higher unhealthy diet score, poorer dietary behaviours but a higher HRQoL score compared to females (P < 0.05). In all students, final regression models indicated: a unit increase in healthy diet score was associated with an increase in HRQoL (unstandardised coefficient(B)±standard error(SE); B = 0.02 ± 0.01(SE); P < 0.02); and a unit increase in unhealthy diet scores was associated with a decrease in HRQoL (-0.01 ± 0.00; P < 0.05). In rural students alone, a unit increase in unhealthy diet score was associated with a decrease in HRQoL (B = -0.01 ± 0.00; P = 0.002), and in urban students a unit increase in healthy diet score was associated with an increase in HRQoL (B = 0.02 ± 0.00; P < 0.001).

CONCLUSIONS: Cross-sectional associations between diet quality and HRQoL were observed. Dietary modification may offer a target to improve HRQoL and general well-being; and consequently the prevention and treatment of adolescent health problems. Such interventions should consider gender and locality.

Urban amphibian assemblages as metacommunities

1. Urban ecosystems are expanding throughout the world, and urban ecology is attracting increasing research interest. Some authors have questioned the value of existing ecological theories for understanding the processes and consequences of urbanization.
2. In order to assess the applicability of metacommunity theory to urban systems, I evaluated three assumptions that underlie the theory – the effect of patch area, the effect of patch isolation, and species–environment relations – using data on assemblages of pond-breeding amphibians in the Greater Melbourne area of Australia. I also assessed the relative impact of habitat fragmentation, habitat isolation, and changes to habitat quality on these assemblages.
3. Poisson regression modelling provided support for an important increase in species richness with patch area (pond size) and a decrease in species richness with increasing patch isolation, as measured by surrounding road cover. Holding all other variables constant, species richness was predicted to be 2·8–5·5 times higher at the largest pond than at the smallest, while the most isolated pond was predicted to have 12–19% of the species richness of the least isolated pond. Thus, the data were consistent with the first two assumptions of metacommunity theory evaluated.
4. The quality of habitat at a pond was also important, with a predicted 44–56% decrease in the number of species detected at ponds with a surrounding vertical wall compared with those with a gently sloping bank. This demonstrates that environmental differences between habitat patches were also influencing amphibian assemblages, providing support for the species-sorting and/or mass-effect perspectives of metacommunity theory.
5. Without management intervention, urbanization may lead to a reduction in the number of amphibian species persisting in urban ponds, particularly where increasing isolation of ponds by roads and associated infrastructure reduces the probability of re-colonization following local extinction.

Regional variations in walking for different purposes : the south east Queensland quality of life study

Where people are located can influence behavioral choices and health outcomes through the effects of place on health. Walking is the most commonly reported form of nonoccupational and nonhousehold physical activity for adults. It is a behavior of particular interest to those in the transportation, urban planning, and public health fields. Researchers have examined patterns of walking from both an individual perspective (psychological and social factors) and from a broader community focus (location and built environment factors). The majority of studies have examined walking in the context of urban environments. Variations within regions (urban, periurban, and rural, for example) in walking have not been previously described. We use data from a regionally based quality of life survey to examine subregional variations in walking for particular purposes. Both the social and contextual variations that may underlie these differences are considered. This is useful in helping identify particular factors that may be further investigated in disaggregated analyses using GIS methods to identify specific differences in objective attributes between subregions that may influence peoples' choices to walk, such as walking infrastructure and the availability of destinations.

The health equity dimensions of urban food systems

There is increasing recognition that the nutrition transition sweeping the world’s cities is multifaceted. Urban food and nutrition systems are beginning to share similar features, including an increase in dietary diversity, a convergence toward “Western-style” diets rich in fat and refined carbohydrate and within-country bifurcation of food supplies and dietary conventions. Unequal access to the available dietary diversity, calories, and gastronomically satisfying eating experience leads to nutritional inequalities and diet-related health inequities in rich and poor cities alike. Understanding the determinants of inequalities in food security and nutritional quality is a precondition for developing preventive policy responses. Finding common solutions to under- and overnutrition is required, the first step of which is poverty eradication through creating livelihood strategies. In many cities, thousands of positions of paid employment could be created through the establishment of sustainable and self-sufficient local food systems, including urban agriculture and food processing initiatives, food distribution centers, healthy food market services, and urban planning that provides for multiple modes of transport to food outlets. Greater engagement with the food supply may dispel many of the food anxieties affluent consumers are experiencing.

Landscape influences on avian density in urban remnant vegetation

The management of urban environments is an increasingly important issue on an international scale as humans emigrate from rural areas to cities. Designing cities that can sustain mass human expansion while maintaining biodiversity is becoming an increasingly complex challenge for land managers. This is largely due to the lack of knowledge on how urbanization impacts upon biodiversity. Our previous research has highlighted the importance of urban remnant vegetation for avian diversity, but also suggested that landscape scale influences may have considerable impacts on the ability for a remnant to sustain species. We have since conducted a study examining avian diversity in 38 urban remnants ranging in size from 5ha to 107ha. These sites vary in relation to the quality of vegetation in the patch and their level of isolation from other remnant patches. This talk discusses the relative influences of remnant patch size, vegetation quality and isolation on avian diversity in urban remnant vegetation. We discuss how the findings of this research could be applied to managing avian diversity in the urban landscape.

Surviving urbanisation : maintaining bird species diversity in urban Melbourne

The relationships between vegetation and bird communities within an urban landscape are synthetised, based on a series of studies we conducted. Our studies indicate that streetscape vegetation plays an important role in
influencing urban bird communities, with streetscapes dominated by native plants supporting communities with high native species richness and abundance, while exotic and newly-developed streetscapes support more introduced bird species and fewer native bird species. Native streetscapes can also provide important resources for certain groups of birds, such as nectarivores. Our research has also revealed that urban remnants are likely to support more native bird species if they are larger and if they contain components of riparian vegetation. Vegetation structure and quality does not appear to be as important a driver as remnant size in determining the richness of native bird communities. Introduced birds were shown to occur in remnants at low densities, irrespective of remnant size, when compared to densities found in streetscapes dominated by exotic vegetation. We discuss our results in terms of practical planning and management options to increase and maintain urban avian diversity and conclude by offering suggestions for future fields of research in terms of urban bird communities.