New homes could double the amount of pollution seeping from septic tanks into Crystal River and Kings Bay, according to a new study. If areas not served by sewer systems are developed fully, the number of septic tanks around the two connected bodies of water could double from the existing 985, the study states.
"The one thing that was surprising to me is the number of septic tanks out there and the number of potential tanks," said Scott Stevens of the Southwest Florida Water Management District, commonly known as Swiftmud.
"We're talking about almost 2,000 septic tanks within a mile of Kings Bay."
The $65,000 study, which cataloged both septic tanks and sewer treatment plants and their potential problems, is part of a multiyear project to begin restoration of the deteriorating water quality of Kings Bay and Crystal River.
Ayres Associates, which carried out the study, is scheduled to present the results this morning at Swiftmud's Coastal Basin Board meeting in Brooksville.
The treated sewage from septic tanks and sewer plants often contains nitrogen and phosphorous products.
These nutrients encourage the growth of aquatic plants, such as hydrilla, that clog waterways.
In separate studies, Swiftmud is looking at storm-water runoff and the water from the springs in Kings Bay and the Crystal River as potential sources of nutrients.
An earlier study found that the springs are a major source.
Both studies stress that volume is not the only factor.
Although septic tanks may produce a small percentage of the nutrients, they may be a problem when they are on stagnant canals that keep the nutrients in.
Nutrients that come out of the springs may be washed out quickly to the Gulf of Mexico with the vast volume of water coming out with them, Stevens has said.
The latest study identified seven sewer plants close to Kings Bay and the Crystal River.
Most of the plants have percolation ponds, which can pollute if improperly maintained, the study states.
Possible solutions include disposing of the treated sewage at inland sprayfields, away from the waterways.
The vegetation at the sprayfields should be harvested regularly to allow it to continue to absorb nutrients, the study states.
Crystal River is expected to switch from the current direct discharge into a Kings Bay canal to an inland sprayfield by next year.
The treated sewage from the package plant at Plantation Inn irrigates its golf course.
The study also found that the area soils are not ideal for septic tanks because of the high water table.