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Sarasota Bay Estuary Program releases 2023 water quality report card

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Yesterday, we received the final batch of water quality data for 2023, which allowed us to update our Ecosystem Health Report Card for the period of 2006 up to 2023. As you know, 2023 was a drought year, and we anticipated that we’d see further trends of improving water quality - which is what happened. As a reminder, the SBEP’s Report Card is not simply water quality, but it also includes information about the amount of macroalgae found on the bottom of the bay, and the acreage of seagrass. The water quality data are from more than 300 samples collected and analyzed by Manatee County and Mote Marine Laboratory (for Sarasota County). The macroalgae data are from 540 stations visited by snorkeling to the bottom of the bay. Our seagrass maps are created every two years by the Southwest Florida Water Management District (SWFWMD). For the seagrass maps, the last time we had numbers was for mapping in 2022, so those numbers are carried over into 2023.

The scoring is based on the Reference Period of 2006 to 2012, for each bay segment. That reference period was chosen because we had lower levels of nitrogen and chlorophyll-a (a measure of phytoplankton) than the next seven years, and we had a 28% increase in seagrass coverage. Basically, this bay was healthier during 2006 to 2012 than during the years 2013 to 2019. Why so? Well, a big reason is because our bay-wide nitrogen loads were about 20% lower in 2006 to 2012 than 2013 to 2019. That difference in nitrogen loads gave us our 2021 pollutant load reduction goal of 20%, or 12 tons of Dissolved Inorganic Nitrogen (DIN).

The great thing about working with our local government is that the combination of stormwater retrofit projects and recently completed and ongoing upgrades to our wastewater treatment processes seem to have already allowed us to meet that 12 tons per year DIN load reduction goal. That is the most likely reason why our bay’s water quality has improved so much over the past few years – from 2020 up to 2023. Our Ecosystem Health Report Card is thus based on how closely we align with the conditions that existed during the 2006 to 2012 reference period. Results are color-coded: blue and green boxes represent conditions that are similar to or better than what we had in the Reference Period. Yellow boxes represent deviations from those Reference Period Conditions that require attention, and Red boxes represent a condition where remedial action is needed.