Development of indicators and framework for assessing river health in peri-urban landscapes : a case study of the Hawkesbury-Nepean River system

The main objectives of this thesis are to: (i) examine the concept of river health through views and expectations of stakeholders; (ii) identify and evaluate the key river health indicators related to the main functions and uses of the river system and, (iii) develop a flexible river health assessment framework which can be adapted to other river systems. The Hawkesbury-Nepean River system (HNR), a complex river in peri-urban landscape in south-eastern Australia, is used as a case study to achieve the objectives of this thesis. The first three chapters of this thesis are dedicated to understanding the social implications of river health including its meaning while the remaining chapters progressively explore the key indicators of river health assessment and attempt to develop a simple framework and tools for sustainable management of river health. The analysis of the primary and secondary data collected in this study indicated that water temperature has an important influence on phytoplankton community structure and downstream prawn harvesting (M. macleayi). The community patterns of benthic macroinvertebrates were influenced by water pH. The historical records revealed how the water temperature has significantly increased since the 1980s and it is expected that future rising temperatures due to climate change may have a significant influence on the phytoplanktons and commercially viable fisheries industry in the river system. Aphanocapsa holsatica and Chironomid larvae appeared as the important indicators for upstream and downstream site differences in water quality. A seasonal succession of phytoplanktons indicated that summer, autumn and winter samples were dominated by Cyanophyta, Chlorophyta and a mix of species respectively. As the final stage of this study, a four-step framework (understand, identify, develop and apply) was proposed to assess river systems based on the key findings of this study. The framework starts by understanding the social and environment aspects related to river health. This is further evaluated in conjunction with multivariate statistical methods to identify key indicators to assess river health. Particular attention is given to retain variables that are cost effective, easy to measure and less labour intensive for routine monitoring purposes while providing valuable information on the condition of the river system. Finally, this information is utilised to develop reach specific river health assessment tools addressing the key services of the river system (i.e., irrigation, recreation). The framework developed in this thesis indicates a higher degree of flexibility, as it does not advocate a single method of assessment for rivers in different landscapes, considers local knowledge in great detail and attempts to develop tools for key river uses. Overall, the river water quality data analysed during this study helped in identifying a number of key indicators for routine and rapid monitoring purposes. In particular, selected key indicators were incorporated into a framework and predictive tools for assessing eutrophication and microbial risk for recreational activities

Community perspectives on managing health of peri-urban river system : evidence from the Hawkesbury-Nepean river catchment, Australia

In this study, we examine aspects of community values and perspectives on goods and services received from the river along with issues related to sustainable management of the river. The study reveals that the contemporary values placed on rivers by communities are mostly associated with recreational and leisure activities. The distance from the river and age of the participants appeared as the most influential social demographic factors affecting participants' perspectives on river health. The study indicates that people tend to develop a strong bond with the natural resources around them and the amount of time spent at a location is directly related to the strength of this relationship. To assess the general river condition and health, a number of visual indicators (e.g., floating debris) were suggested. If properly standardised and calibrated, such indicators have the potential to develop cost-effective monitoring tools for detecting seasonal and spatial changes in river health

Sustainable graywater reuse for residential landscape irrigation : a critical review

The demand for potable water is rising rapidly due to an ever-increasing population, economic activities, and dwindling water supplies. To provide adequate water supplies in the future, understanding the issues and challenges in the reuse of water and developing appropriate strategies for reuse will be critical. One way to augment water supplies for residential use is to reuse graywater – the wastewater from kitchens, bathrooms, and laundries. In this article, we critically review the evolution of water reuse, the definition of graywater, graywater reuse practices, volumes and flow in different situations, and graywater characteristics. We then examine the issues associated with different graywater treatment methods and how using graywater for irrigation around homes affects soil quality and plant growth. The study concludes that graywater treatment costs, human health risks, and its effect on soil quality are some of the challenges that need to be addressed in the future for widespread and sustainable reuse of graywater for irrigation around homes

Sustaining the river health in peri-urban fringes : multiperspective analysis through key informant interviews

Using the Hawkesbury-Nepean River (HNR) system in New South Wales, Australia, as a case study, a key informant technique involving active river users (n = 3), researchers (n = 3), managers (n = 4), and river-interested-groups (n = 4) was used to examine the issues, problems, and factors affecting the management of peri-urban river systems. The study clearly highlighted the difficulty involved in defining the term river health in the context of peri-urban landscapes due to a multitude of stakeholder interests. In particular, a number of organizational objectives, personal interests, and the level of engagement of people with the river system influenced the meaning of river health. The study also indicated how the health of the HNR system has been impacted considerably by ongoing urbanization in the catchment, increased recreational activities, and ad hoc changes in government policies. Such pressures can be identified and river health can be assessed if proper indicators related to aspects of ecological and social functions are available. In addition, key informants strongly perceived river health as a shared responsibility between government agencies and river users, and the importance of a single entity to effectively facilitate the needs of different stakeholders and protect river health. In general, effective management of peri-urban rivers must be accompanied by ongoing but continuous changes to policy, planning strategies, and assessment techniques, which is lacking in present management programs

Impacts of water quality on the harvest of school prawn (Metapenaeus macleayi) in a Peri-Urban river system

The school prawn (Metapenaeus macleayi) is important among commercial prawn trawler operators, but its harvest is affected in a complex way by a number of interacting water quality, and other variables. In this study, using the HawkesburyNepean River system as a case study, we use Pearson correlation and hierarchical agglomerative cluster analysis (HACA) to assess the influence of the selected water quality (n = 7), quantity (n = 1), and weather (n = 2) parameters on the prawn harvest. Using data records (n = 104) collected over a 9-y period, we found water temperature (r = 0.63, P < 0.01), dissolved oxygen (r = -0.59, P < 0.01), and rainfall (r = 0.26, P < 0.01) to be significantly correlated variables with prawn harvest. The HACA produced 3 distinct clusters of variables nutrient availability for prawns (the total nitrogen, the total phosphorus, reactive silicate, turbidity, and suspended solids), the physical river environment (temperature, rainfall, and river flow), and the biochemical river environment (dissolved oxygen and chlorophyll a). The study revealed that 2 key variables, viz., temperature and rainfall, representing the physical river environment are statistically significant in affecting prawn harvest in the study area. Therefore, from fishing industry point of view, the future river management need to focus on strategies that will improve the physical river environment, particularly to cope with the impacts of future peri-urban development and climate change scenarios

Reuse of greywater for irrigation around homes in Australia : understanding community views, issues and practices

We examined people's views on a number of water issues and their motivation, practices and concerns about greywater reuse for irrigation of around homes. Survey participants (275) from different socio-economic background from 125 suburbs in the Western Sydney region, Australia took part in the study. Regardless of their age and gender, when asked which was the most important issue regarding water in their region from a prescribed list, the majority of participants identified water quality as the most important and availability without water restriction as the least important. About half of the participants reused greywater regularly or at some time during the last few years. The cost of plumbing and health risks to people, plants and soil are critical issues for greywater reuse and need attention. For the reusing widely and sustainably, there is a need for easily accessible, user-friendly information packages to create 'greywater reuse literacy' in the community

A framework for assessing river health in peri-urban landscapes

The definition and assessment of the health of river systems is a difficult and complex task. This is mainly because river systems are distributed over a large geographical space with unique biotic and abiotic characteristics attributed to a given catchment, the existence of competing perceptions of stakeholders and an inability to establish a clear rationale for a universal river health assessment methodology. Such complexity and uncertainty can be addressed through a river health assessment framework with step-by-step guidance to help river health management authorities develop site-specific tools suitable for their river systems by taking into account the local river ecohydrology, hydrobiology, water quality aspects and insights from river users. The present work proposes a river health assessment framework based on the key outcomes of a three year project and showcases the role of each step in the framework. The proposed framework consists of four steps: understand, identify, develop and apply. During the first step, a comprehensive understanding is obtained using historic and current water quality data. This information is supplemented with community understanding of the changing condition of river health. This knowledge is then used together with relevant multivariate stoical techniques to identify some key indicators for river health monitoring and assessment. Finally tools are developed to assess river health for community, environmental and management purposes. We developed two tools to assess the risk associated with river health for primary contact recreational activities and algal blooms using three key indicators

River health assessment in peri-urban landscapes : an application of multivariate analysis to identify the key variables

An array of river health assessment approaches and water quality variables have been suggested in the past for assessing the level of river health. However, the selection of suitable variables to be monitored for the assessment remains ambiguous and often it is not practical to monitor all the suggested variables. In this study, we employ a multivariate data reduction technique, called Factor Analysis (FA), to identify the key river health variables for a peri-urban river system, viz., the Hawkesbury-Nepean River system in New South Wales, Australia. Out of 40 water quality variables included in the analysis, the FA identified nine key variables, under three varifactors (VFs), explaining 50% of the variance in the river water quality. Variables in the first, second and third VFs revealed anaerobic conditions, microbial quality and effects of eutrophication in the Hawkesbury-Nepean River. Thus, the present work shows a notable reduction in the number of variables and the application of FA for identification of key variables was found promising. The finding of this study has potential application in designing a cost-effective river health monitoring program by reducing the number of variables to be monitored in a peri-urban situation. It can also assist in partitioning variables according to their unique contribution to the total variance

Effects of greywater irrigation on plant growth, water use and soil properties

Glasshouse experiments were conducted to examine the effects of greywater irrigation on the growth of silverbeet plants, their water use and changes in soil properties. The experimental treatments included in the study were: irrigating with 100% potable water (control, treatment T0), irrigating with 100% greywater (treatment T1), irrigating with a mixture of greywater and potable water in 1:1 ratio (treatment T2) and irrigating alternate with potable water for one irrigation and greywater for the next (treatment T3). The pH and EC values of the greywater used in the study were 10.5 and 1358 μS/cm respectively. Results showed that greywater irrigation had no significant effect on soil total N and total P after plant harvest, but there were significant effects on the values of soil pH and EC. Furthermore, there were no significant effects of greywater irrigation on plant dry biomass, water use and number of leaves. For the treatment that involved irrigating with 100% greywater (treatment T1), there was a significant increase in soil pH and EC when compared with the control and the other two irrigation treatments. The study indicated that irrigating silverbeet plants with potable water and greywater in an alternate pattern (treatment T3) had soil pH and EC levels similar to that of irrigation with 100% potable water. This also meant that irrigating alternate with potable water and greywater could reduce some of the soil health risks associated with the reuse of greywater

Perspectives on impacts of water quality on agriculture and community well-being : a key informant study from Sri Lanka

Integrated management of water quality is critical for sustaining food production and achieving overall well-being of a community. Further, understanding people’s perceptions and engagement can play an important role in achieving water and food security. The main aim of this study was to investigate the perspectives of community and other stakeholders as to how water quality impacts on agriculture, livelihood and community well-being within rural farming communities of two dry zone districts of Sri Lanka. The study adopted ‘key informant interviews’ as the methodology to investigate community and other stakeholder perspectives to collect primary data over a period of four months. The interview contents were then examined using a frequency matrix and graphed using an Excel graphing tool. The raw text was also analysed to understand the broader patterns in the text. A fuzzy logic cognitive map (FCM) was developed using the relationships between various concepts and linkages provided by the key informants. All key informants were concerned with the quality of drinking water they consume and the water used for their food preparation. Key informants representing the farming community indicated that the use of poor quality groundwater with higher levels of hardness has made growing crops difficult in the region. The key informants also identified extensive and ongoing use of agro-chemicals and fertilisers as a major source of pollution in water bodies in both spatio-temporal scale. Based on key informant interviews, possible initiatives that can help improve surface water and groundwater qualities for both drinking and agricultural use in the dry zone of Sri Lanka can be categorised into four broader themes, viz., provision of filtering/treatment systems, reduction in the use of agro-chemical and fertilisers, education of community stakeholders and support of alternative options for portable water supplies. The study indicates that in the key informants’ view of groundwater and surface waters’ continued deterioration in the absence of a proper governance structure, a majority of farmers will have restricted access to good quality water to meet daily and agricultural needs, and this will affect the health of the elderly and children in the area. Further, a majority of key informants were of the view that management of surface water and groundwater should be a shared responsibility between the government and the community in the region and appropriate policy initiatives that will improve water literacy at all levels are mandatory to address future water quality challenges