Groundwater nitrate concentrations in wells located at the shoreline of West Falmouth Harbor from 2006 to 2023

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 been measuring groundwater chemistry in wells installed along the shoreline of the harbor to monitor the spatial and temporal patterns in N loading. Water samples were collected approximately annually from 2006 through 2009, and less frequently in subsequent years, and processed for nitrate + nitrite. Full analysis details are available in Hayn et al. 2025 in Estuaries and Coasts (doi: 10.1007/s12237-025-01630-0).