Nitrate and Salinity sampled in West Falmouth Harbor during the wintertime between 2011 and 2024

West Falmouth Harbor (West Falmouth, MA, USA) has been experiencing a dramatic increase in nitrogen loading from an upgradient municipal wastewater treatment facility since the early 2000's. As part of a long-term study into the effects of this nitrogen enrichment, we have measured nitrate concentrations and salinity in water samples collected during the winter months (January, February, March) from the surface waters of the two basins with groundwater inputs impacted by nitrate from the contaminated aquifer. We use these in an open water mixing model to calculate the spatially averaged groundwater nitrate concentration in our manuscript, which we use to calculate the total nitrogen loading to these two basins. This manuscript can be found at DOI: 10.1007/s12237-025-01630-0