Within Australia, Gross Pollutant Traps (GPTs) have been installed in many stormwater drainage networks to improve the storm water quality before its discharge into receiving waters. These GPTs operate by filtering gross pollutants from the stormwater. In many GPTs these filtered pollutants are held within a wet sump until their removal. A significant fraction of the trapped litter can be classified as leaf litter. Before removal, this leaf litter may decay and hence has the potential to release nutrients into the stormwater. Therefore, nutrient management in stormwater needs to consider leaf litter decay trapped in GPTs. The decay of leaf litter stored in a GPT is discussed in the paper. Information for this discussion was obtained from a series of tests simulating the decay of leaf litter in a GPT. These tests used freshly fallen leaf litter collected from Centennial Park in Sydney, Australia.