Project 3.7.4

Wetlands and floodplains: Connectivity and hydrological function

Project Leader: Prof Jim Wallace, CSIRO

This MTSRF-funded project successfully quantified the role of over-bank floods on the transport of sediments and nutrients and their transport across floodplains in the Wet Tropics. This work was instrumental in the prediction of how the hydrological response and connectivity of floodplain wetlands are affected by land use and water management. Researchers have shown that the nutrient loads being delivered during flood events from the Tully-Murray catchments to the Great Barrier Reef lagoon have been significantly underestimated: over bank flood contributions were found to increase the mean annual loads of phosphorus and nitrogen loads by 30-50% above previous river-based estimates. Model simulations provided a means of identifying the degree of connectivity of different wetlands, ranging from those wetlands that are more permanently connected with streams and drains, to those that are connected only when there are large over-bank floods. This information has been integrated into the biological indicator work to help understand movement of freshwater fish. Understanding of the ecological functions of wetlands has been enhanced by this improved knowledge of over-bank fl ow and the reoccurrence of connectivity between wetlands. Variations in wetland connectivity could affect the movement of aquatic biota during floods, and the variability of habitat and biodiversity of individual wetlands. Knowledge of the appropriate corridors and links will be instrumental in any future management of wetlands and/or selection for rehabilitation and restoration.





Report Series No. 53 - Part I: Wallace, J., Hawdon, A., Keen, R., Karim, F., Stewart, L. and Kemei, J. (2010) Wetlands and floodplains: connectivity and hydro-ecological function. Part I - The role of overbank floods in transporting sediments and nutrients to the Great Barrier Reef lagoon

Part II: Karim, F., Wallace, J., Kinsey-Henderson, A., Hawdon, A., Keen, R., Arthington, A. H., Godfrey, P. and Pearson, R. G. (2010) Wetlands and floodplains: connectivity and hydro-ecological function. Part II - Quantification of overbank and channelised wetland connectivity in the Tully-Murray floodplain


Project 3.7.4 CSIRO Hawdon, A. (2007) Design and application of automated flood water quality monitoring systems in the wet tropics


Project 3.7.3 and 3.7.4 CSIRO Wallace, J. (2007) Hydro-ecological modeling in coastal catchments: Connectivity and hydro-ecological function

Report from the MTSRF Projects 3.7.3 and 3.7.4 Workshop held at CSIRO Davies Laboratory, Townsville, 19-20 April 2007, which summarises the presentations, discussion and recommendations made. The key objective of the workshop was to initiate the development of an integrated package of conceptual and quantitative models, supported by field-based research, to predict the key hydro-ecological functions in Wet Tropics rivers, wetlands and floodplains.