Using Satellite Imagery to Implement Nutrient TMDLS

Remote–sensing data, gathered from Landsat images, provides a cost-effective alternative for estimating the concentration of phosphorus and chlorophyll-a in large waterbodies. With accuracy comparable to traditional laboratory analysis of field samples, satellite technology provides numerous advantages. Larger sample sizes provide a more representative estimate, better characterize real-world variability and greater statistical sensitivity to detect changes in causal or response targets. In addition, since NASA has archived Landsat images for more than 25 years, it is now possible to analyze water quality data long after the opportunity to collect field samples has passed. Large quantities of valid water quality data, representing a wide variety of climate conditions and urbanization trends, greatly improves the simulation models that govern most TMDLs.