The geology in some parts of Florida favors an exchange of water and nitrogen between surface waters and groundwater. Is SPARROW valid in these areas?
|Back to Top| As discussed in Hoos and McMahon (2009), the SPARROW approach of explaining instream loads based on watershed attributes has limitations for stream reaches for which the actual hydrologic boundaries do not correspond with the apparent watershed determined from surface topography. This may occur in certain river basins in northern and central Florida where flow exchange with the underlying regional aquifer contributes substantial nitrogen influx to and outflux from the surface-water basins. Model predictions are presented for river basins identified with this concern (Oklawaha, Crystal, Lower Sante Fe, Lower Suwanee, St. Marks, and Chipola River basins) but may be less reliable due to this unmodeled flux component. In addition, accuracy of SPARROW model predictions for the St. Johns River and Indian River basin may be affected by inadequate representation of the hydrologic network by the ERF1_2 digital segmented network used in the model.
