Generalized Methods for Nitrogen Loading Assessment in Contributing Areas of Selected Lakes of Interest

Lakes worldwide are impaired by external nutrient loading due to human activities, specifically agricultural runoff. Excess nutrients can change nutrient dynamics in lakes and contribute to declining water quality. This study utilizes two publicly available datasets, NHDPlus V2 and StreamCat, to investigate and compare the rates of inorganic nitrogen wet deposition, biological nitrogen fixation, and nitrogen fertilizer application within the surrounding watershed of three lakes. To accomplish this, a relational database was created to relate StreamCat values with NHDPlus V2 watershed hierarchy using a unique StreamID. The data from each dataset was loaded into the relational database after performing a geospatial analysis to identify StreamIDs within the watershed for each lake of interest. SQLite queries were then performed to obtain rates of chosen parameters from the relational database in order to compare the three watersheds. This study demonstrated that generalized methods can be developed to relate NHDPlusV2 and StreamCat, in order to simplify querying of water quality data from StreamCat for the watersheds of selected lakes.