Alexander Pardy

Then and Now: Understanding Change on an Agricultural Landscape ©2019

Freshwater eutrophication typically driven by non-point source phosphorus pollution is one of the world's most prevalent and vexing environmental problems with the Laurentian Great Lakes on the Canada – United States border. During 1975 – 1977, the Pollution from Land Use Activities Reference Group examined eleven agricultural watersheds in order to investigate the impacts of land use activities on surface water quality. This study examined how agricultural land use and management has transformed in two watersheds, Nissouri Creek and Big Creek. The goal of this study was to quantify the phosphorus mass balance change within the watersheds. During 2015 – 2019 land use and management practices survey data was collected. Results of this study showed Nissouri Creek is now depleting -2.19 kilograms of phosphorus per hectare of agricultural land, while Big Creek is still accumulating 4.77 kilograms of phosphorus per hectare of agricultural land. This study can guide efforts to limit the long-term losses of phosphorus in the Laurentian Great Lakes and elsewhere.