Florida’s springs and spring run streams are experiencing increased nitrate concentrations relative to historic and background conditions.  In response to legal mandates, and to preserve these ecologically rich resources, St. Johns River Water Management District (SJRWMD) developed concentration targets for nitrate and total phosphorus in the Wekiva River and Rock Springs Run in order to develop Pollutant Load Reduction Goals for these two spring-run streams.  SJRWMD used multiple lines of evidence to derive concentration targets, but largely relied on responses of benthic algal communities to nitrate-nitrite nitrogen (“nitrate”) and total phosphorus, both of which were elevated in these streams.  Data came from studies conducted in these two streams; two reference spring-run streams (Alexander Spring Creek and Juniper Creek); and from algal studies conducted in other spring run streams in Florida.  Nitrate concentration targets of 216 and 221 μg/L for the Wekiva River and Rock Springs Run (respectively) are proposed.  These are mean concentrations based on keeping nitrate levels at or below 250 μg/L for 90% of the time.  Total phosphorus concentration targets of 59 and 61 μg/L for these two streams are similarly proposed, based on keeping total phosphorus at or below 90 μg/L for 90% of the time.