Understanding current and future impacts of public water supply on global nitrogen cycling

Within in the United States some 54 km³ of water is withdrawn annually for public supply. Around 16% of this water is subsequently lost through leakage as it moves through distribution networks. These processes not only have implications both economically and for water security, but the substantial redistribution of water has also been shown to cause significant perturbations in elemental cycling. Due to its importance for ecological health and global food production, this research attempts to quantify the nitrogen (N) fluxes associated with a range of Public Water Supply processes, such as abstraction and leakage. Using county level data sets, these N fluxes will be determined across the contiguous United States, and the significance of results evaluated through comparisons with other quantified N fluxes. Assessments will also be made on how the absolute and relative significance of these fluxes may change in the future, such as due to evolving water demands as a result of the combined drivers of changing climate and increasing population. Outputs from the US will form part of a wider global assessment, including comparisons with less developed countries.