A collaborative project between the National Park Service, engineers from Syracuse University, and The University of Tennessee was conducted in order to determine the maximum amount of deposition which can be received without having harmful effects to park biota, or the critical loads (Total Maximum Daily Load/ TMDL), of the compounds (Nitrate and Sulfate) which are responsible for the majority of acid deposition. The study modeled deposition using water quality data collected by the University of Tennessee, Trout Unlimited volunteers, and the National Park Service. The model was used to create a hindcast or an estimate of historical levels and to predict the response to increases or decreases of deposition in the future. Results suggest that if there is no change in atmospheric deposition then the acid neutralizing capacity (ANC) of the watersheds of the park as well as the pH of streams will continue to decrease. According to the model, in order to increase the ANC of the watershed in question to levels which are suitable for trout, both Sulfate and Nitrate must be reduced. The current rate of deposition is 0.6 keq/ha-yr to 3.2 keq/ha-yr. In order to increase the ANC of all test sites to 0 microeq/L by 2050, the model indicates deposition should be decreased to 1keq/ha-yr (Zhou et al. 2014).