Nitrogen and phosphorus entering the Chesapeake Bay must be reduced to meet the requirements of the Environmental Protection Agency (EPA) 2010 Chesapeake Bay Total Daily Maximum Load (TMDL). Lake fertilization by the Virginia Department of Game and Inland Fisheries (VDGIF) is both an accepted management tool for fisheries enhancement and necessary when allochthones sources are limited. The problem is whether or not the addition of fertilizers to recreational fishing lakes is contributing to nutrient loading of the Bay. Since March 2017 we have been conducting a comprehensive lake water chemistry evaluation of four lakes in the watershed of the Bay: Lake Brittle, Burke Lake, Huntsman Lake and Lake Shenandoah. The first two were fertilized by application of Sportmax® during the summer. Samples were taken at each lake from feeder streams, tail waters and within-lakes, assayed and compared for the evaluation. More than twenty chemical and analytical parameters have been measured. Stream gauge records were used to develop loading and discharge values for water volume, that were combined with observed concentration values to produce nutrient budget data. For the sixteen months to date, we have found that total nitrogen (average two week loading and release in kg) for the four lakes has been: Brittle (38.0; 14.7), Burke (35.5; 10.2), Huntsman (11.8; 24.7) and Shenandoah (45.8; 21.6) and for phosphorus: Brittle (16.2; 4.7), Burke (67.4; 7.1), Huntsman (3.9; 15.1) and Shenandoah (6.0; 4.4). The data indicate that all three VDGIF lakes are currently storing both nitrogen and phosphorus, while Lake Huntsman is releasing more nutrient than it is currently entering. Huntsman was dredged and refilled in 2014 and we believe that the disturbance may be a contributing factor to the nitrogen and phosphorous release. Sediment analyses revealed that all four lake have phosphorus stored in the muds.

Additional Abstract Information

Student(s): Louis Bondurant, Madison Roberts

Department: Chemistry and Biochemistry

Faculty Advisor: Dr. Daniel Downey

Type: Oral

Year: 2019

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