07 Nov Evan Chua
Dr Evan Chua is a researcher at CQUniversity, Rockhampton. He completed his Environmental Science Degree at RMIT University, completing an honours year project in microplastics pollution in Port Phillip Bay Victoria, before moving to Queensland to take up a PhD project studying river pollution and fish community impacts in Central Queensland. He completed his PhD at CQUniversity in 2018. His research focuses on the environmental impacts agricultural and resource extraction activities, understanding the effects of poor water quality on fish communities in Queensland’s freshwater and coastal waterways, and applying that knowledge to better manage and monitor waterways in Queensland.
The Influence of Riparian Vegetation on Water Quality in a Mixed Land Use River Basin in Central Queensland
Worldwide, agricultural activities are associated with environmental impacts including riparian degradation and increased waterway pollution. The Fitzroy Basin of Central Queensland is the Great Barrier Reef’s largest river basin and also lies within the Brigalow Belt Bioregion, which in recent years has experienced the highest rates of tree clearing in Australia. Land use in the Basin is dominated by beef cattle grazing, and the riparian zones of waterways are subject to agricultural impacts. Local riparian condition however, has not been consistently monitored within the Fitzroy Basin nor has its relationship with water quality been well established. This study assessed riparian condition of waterways in the Fitzroy Basin using two established scoring methods (the Rapid Appraisal of Riparian Condition and the Australian Rivers Assessment System Habitat Assessment) and statistically investigated the relationship between stream water quality (nutrients, metals and physicochemical parameters) and local riparian condition. Twelve sites in six waterways were sampled four times over two years, during ambient (non-flood) conditions. Upstream creeks with poorer riparian condition had elevated dissolved organic carbon (DOC), total nitrogen (TN), dissolved manganese, and sulfate concentrations than river sites with more intact riparian zones. High concentrations of these parameters were associated with poor local riparian scores in principal components analysis. DOC and TN were very significantly negatively correlated with riparian scores (r values: −0.55 to −0.69; p < 0.001). Dissolved manganese and sulfate were included in the multiple regression model for riparian scores. The results suggest that preventing riparian damage and restoring riparian vegetation could play an important role in improving water quality in Queensland’s waterways.