Host: Dr Ben Gilby, University of the Sunshine Coast

Alistair Grinham, University of Qld

Dr Alistair Grinham has over 20 years’ experience in monitoring sediment dynamics of rivers, freshwater reservoirs and coastal systems. Alistair joined the School of Civil Engineering in June 2007 to develop environmental monitoring systems to better understand sediment transport and biogeochemical processing in freshwater and marine systems. Alistair employs a multi-disciplinary approach using traditional campaign-style monitoring programs along with advanced autonomous monitoring systems to ensure data collection occurs at appropriate spatial and temporal scales. These award winning monitoring systems have been successfully applied to water quality and sediment investigations across a diverse range of water bodies, including over 15 years of ongoing programs in Moreton Bay and its catchment.

Abstract

Pumicestone Passage is a tidal waterway of high cultural, ecological and recreational value, located in Northern Moreton Bay, South-East Queensland. In the last 150 years, the Passage has come under increasing pressure from catchment modification and increasing community concern over waterway health. A comparative study was conducted in order to establish current sediment quality and distribution in the Passage with past surveys undertaken in 1980 and 2015. This comparison has shown that overall, the Passage experienced a significant increase in mud distribution, attributed mainly to extensive land clearing and construction of urban development. However, the trend is complicated and comparison with the 2015 survey show some areas are experiencing decreases in mud. A potential driver identified for this may be changes in catchment management. A significant reduction in metals, and no detectable pesticides were further identified, highlighting the effects of land use changes on these. Overall, the study findings indicate that Pumicestone Passage is a highly variable environment, where a complex range of systems affect sediment quality and distribution. The study provides a baseline data set, relevant for future comparison in the face of continuing urbanisation.