Effects of Land Use on Nitrogen and Phosphorus Inputs to the Indian River Lagoon

Urban and residential land uses in the Indian River Lagoon IRL watershed contribute
sewage and fertilizers to stormwater runoff, resulting in increased nitrogen N and phosphorous P
loadings that can fuel harmful algal blooms. The goal of this project is to quantify dissolved
concentrations of ammonium, nitrate and soluble reactive P in storm water from agricultural,
natural, and urban land uses adjacent to seven of the canals and tributaries within the IRL
watershed. Preliminary results based on water samples taken at the beginning, middle and end of
storm events at 10 sample points suggest initial spikes of soluble reactive P, nitrate and ammonia
in storm water runoff. These results represent the first attempt to characterize nutrient
concentrations of stormwater among various tributaries and land uses on the IRL.