This data release supports analyses of the relations between monthly average nutrient concentrations in the Herring River on the ebb tide near Wellfleet Massachusetts and monthly average precipitation, temperature, runoff, solar radiation, ocean water temperature, mean sea level, nutrient concentrations in Wellfleet Harbor, and atmospheric deposition of nitrogen 2015-2021. The Environmental_Variables.csv file contains the monthly average precipitation, temperature, runoff, solar radiation, ocean water temperature, mean sea level, nutrient concentrations in Wellfleet Harbor, and atmospheric deposition of nitrogen data. The Velocity_andgage_height.csv file contains the data on surface water velocity that were used to determine the time of the beginning of flood and ebb tides from June 2020 through December 2021. The gage height data were used as a backup to the velocity data for determining the time of the beginning of flood and ebb tides.