The map on the right shows salinity in the lagoon in May 2002. In May the ongoing drought had kept freshwater out of the lagoon but evaporation continued, concentrating the salt already in the lagoon. Evaporation removes freshwater and leaves the salt behind concentrating it. As a result, the Mosquito Lagoon and the areas marked in white near inlets had salinities even higher then the ocean itself. This is called supersaline. Around Cocoa the salinity levels were in the low 20’s, (marked by a slash line on the map). The rest of the lagoon was between 25 and 35 ppt. Overall the salinity throughout the drought was unusually high and had much healthier levels of salinity then during non-drought years. Contrast that to the map on the next page from August, just three months later. The drought ended with a higher than normal rainy summer pouring millions of gallons of freshwater into the lagoon. The cloudy skies associated with the daily storms also reduced the amount of evaporation that otherwise would have removed more of the freshwater.

   Along with the fresh water comes a load of other pollutants like sediment that clouds the water and nutrients that stimulate algal blooms and low dissolved oxygen levels. Indian River County around Vero, (marked with a crosshatch on the map), was hit with heavy rains that drained to three main canals connected to the lagoon. The graph on the next page show that during periods of July and August, Indian River County had salinities in single digits - the lowest recorded salinities we have ever measured in the lagoon these past eleven years. The Lagoon in Indian River County is at its narrowest so there was not as large a volume of high salinity water to counterbalance the flood of freshwater as there was in other areas. St. Lucie River, St. Sebastian River and the other larger tributaries to the lagoon also had their salinities plunge as stormwater drained from local canals. St. Lucie River was further impacted by water releases from rain-flooded Lake Okeechobee. If not for the unusually high salinities at the start of the summer, the rainfall would have pushed salinities to even lower levels.