Urban Creek flow, re-aeration and ecological health

Abstract

For two years we studied the health of a lowland freshwater ecosystem, Moggill Creek, flowing through the western suburbs of Brisbane Qld, Australia. We found: Terrestrial organic carbon was most likely driving very high bacterial growth and respiration rates that removed dissolved oxygen from the water. The diversity of fish and invertebrates was high and the overhanging riparian vegetation cover limited algal and cyanobacterial production. Overall the creek was in fair to good health—Report Grade“D”. Conclusion: Water column dissolved oxygen concentrations and Creek health relied on environmental flow during rain to physically re-aerate the water to counter the high bacterial consumption of oxygen that resulted from the respiration of the organic carbon loads that were entering the ecosystem.