Once we take the sum of all the phosphorus added to the lake from external sources, we can estimate the Phosphorus concentration in the lake. Our model gave us a concentration range of 5 to 22.8 ppb, with a best estimate of 12.4 ppb. Since this is very close to the average phosphorus concentrations in the epilimnion found by in our water quality analysis, we can be fairly sure of the ability of the model to predict where phosphorus is actually coming from in the watershed.