Tampa Bay Gets Green Light on Water Quality Report Card

BRADENTON -- All major segments of Tampa Bay met water quality targets in 2012, for only the fourth time since baywide assessments began in 1974.

2012 Water Quality Report Card"This is an impressive testament to the collective efforts of both local governments and private industries to reduce pollution in the bay, especially when you consider that the population around the bay has grown by  more than 1  million people since 1974," said Holly Greening, TBEP Executive Director. "Tampa Bay is one of the few estuaries in the nation that is showing this kind of sustained improvement."

To help track seagrass recovery, the Tampa Bay Estuary Program annually compares water quality to established targets in the bay and reports the results through the "Decision Matrix." This simple report card uses a red, green and yellow color system to assess overall water quality in the bay. The rating system considers the amount of microscopic algae in the water (as indicated by chlorophyll a, a plant pigment), as well as the amount of visible sunlight penetrating the water column.

"Green" means the bay segment is meeting water quality targets, while "red" means water quality is inadequate to support seagrass. "Yellow" indicates caution, signaling that the area bears watching.

The 2012 analysis shows a green light across the board, meaning that water clarity in all four bay segments - Hillsborough Bay, Old Tampa Bay, Middle Tampa Bay and Lower Tampa Bay - is good enough to foster continued recovery of underwater seagrasses that are the backbone of a healthy bay.  This is an improvement over the 2011 assessment, which resulted in a red rating for Old Tampa Bay for failing to meet either the chlorophyll a or light penetration targets. A series of large algae blooms have plagued Old Tampa Bay in recent summers, and TBEP is conducting a comprehensive, large-scale research effort to identify causes and potential remedies to the persistent problems facing this bay segment north of the Gandy Bridge.

More information about the bay's overall health will come this Spring when seagrass surveys conducted by the Southwest Florida Water Management District are released. The last seagrass surveys, covering 2008-2010, documented an increase of 3,250  acres. Those gains resulted in total seagrass acreage of 32,897 acres  - more than at any time measured since the 1950s.  Scientists are optimistic that the good water quality report will translate to additional seagrass gains from 2010-2012.

Seagrasses, which generally grow in waters less than 6 feet deep, are an important barometer of the bay's health because they require relatively clear water to flourish. With improvements in wastewater and stormwater treatment, and checks on dredging and filling activities, Tampa Bay has regained more than 9,000 acres of seagrasses since 1982.

However, nitrogen remains the primary pollutant in the bay. Too much of this essential plant nutrient fuels algae blooms that cloud the water, prevent sunlight from reaching seagrasses and reducing oxygen levels. An algae bloom that at times stretched for 14 miles plagued Old Tampa Bay from north of the Courtney Campbell Causeway to the Gandy Bridge for three of the last four summers, and smaller blooms have appeared in Hillsborough Bay off downtown Tampa.

Greening credits regional efforts to reduce nitrogen contained in stormwater runoff for the good report card. The Tampa Bay Nitrogen Management Consortium - an alliance of local governments and key industries bordering the bay - has collectively invested more than $500 million in projects to reduce nitrogen pollution since the 1990s. And several communities have adopted strict limits on the amount and type of fertilizer that can be applied to lawns to prevent summer rains from washing fertilizer residues into the bay.

Data on water clarity is collected by the Environmental Protection Commission of Hillsborough County from more than 45 sampling stations scattered throughout the bay.The water quality targets used for the Decision Matrix were developed by TBEP's Technical Advisory Committee, composed of area scientists and environmental managers.

The targets are specific to each bay segment because water quality naturally varies throughout the bay. For example, the water in the upper part of the bay is generally less clear than the water in the lower bay nearest the Gulf of Mexico.  The water quality targets for the upper bay are less stringent but similarly protective for restoring seagrass.