Professor Isaac R Santos

Radon is a natural occurring noble gas and is an excellent natural tracer of groundwater. Carbon dioxide is an important but
unquantified component of surface waters in Gold Coast canals and is often overlooked in carbon budgeting. By coupling
radon and pCO2 measurements it can be determined how much carbon dioxide is entering canals through groundwater
pathways. The purpose of this study is to categorise canal types according to their level of connectivity and geomorphology
and determine how these factors drive carbon dioxide fluxes. To evaluate this, a high resolution survey was conducted along
approximately 300 kilometres of Gold Coast canals and waterways in October 2013. Overall, residential canal estate waters
were supersaturated with carbon dioxide with partial pressures ranging from 400 to 1370 μatm. pCO2 increased in areas of
reduced connectivity with lower pCO2 in areas of higher connectivity. A significant correlation between radon and pCO2 implied
that groundwater seepage was a major driver of carbon dioxide within the canal system. These results may assist in the design
of new canals or re-engineering of existing canals to reduce the greenhouse gas footprint of these developments.