# Presentation: 351542

## Evidence for Rapid Transport of Recharge from Onsite Sewage Treatment and Disposal Systems to Groundwater at Manatee Springs State Park.

- By Eberhard Roeder1, Harmon Harden2, Jeff Chanton2, Mark Hooks1
- 1FL Dept. of Health, Division of Environmental Health
- Bureau of Onsite Sewage Programs
- 2Florida State University, Department of Oceanography

- USGS Cedar Key 09/22-24/04

## OSTDS Karst Study

- Hypotheses:  Rapid flow of recharge into and through the groundwater and limited attenuation of any components of the recharge
- Test with wastewater effluent from two Onsite Sewage Treatment and Disposal Systems (OSTDS) as recharge
- Tracer Test (inject 50 gal in ~45 min into drainfield)
- Fluorescein (soluble)
- Sulfur Hexafluoride (SF6) (volatile)
- Groundwater quality monitoring
- Nitrate (soluble, product of functioning drainfields)
- Total Phosphorus
- Fecal Coliform

- USGS Cedar Key 09/22-24/04

## Manatee Springs is remote, so OSTDS can be studied in relative isolation from other sources of nutrients 
Two OSTDS (septic tank and drainfield) 
River front/shallow water table and 
Upland/deep water table

- Manatee Springs is remote, so OSTDS can be studied in relative isolation from other sources of nutrients
- Two OSTDS (septic tank and drainfield)
- River front/shallow water table and
- Upland/deep water table

- Manatee Springs State Park

- USGS Cedar Key 09/22-24/04

## Magnolia II: River Front Site

- Shallower water table (4-9 feet)
- Built into mound for flood protection

- USGS Cedar Key 09/22-24/04

## Tracers at Magnolia II

- M-1:  75 feet from injection point
- Fl arrival in 2.5 days

- M-3: 135 feet from injection point
- Fl arrival in 1.4 days

- USGS Cedar Key 09/22-24/04

## Nitrates at Magnolia II

- USGS Cedar Key 09/22-24/04

## Hickory:  Upland Site

- Deeper water table (12-15 ft)
- On top of Manatee Springs cave system

- USGS Cedar Key 09/22-24/04

## Tracers at Hickory

- S-1:  35 feet from injection point
- SF6 arrival within one hour

- S-3: 165 feet from injection point
- SF6  arrival within one hour

- USGS Cedar Key 09/22-24/04

## Hickory: Tracers in Surface Water

- SF6 in surface water

- Fluorescein in surface water

- USGS Cedar Key 09/22-24/04

## Nitrates at Hickory

- Bathhouse closed

- USGS Cedar Key 09/22-24/04

## Results

- Transport velocities (based on tracer arrival times):
- Magnolia II, from 5 to 100 feet per day
- Hickory, from 1 to 280 ft/day
- More than one peak in many monitoring well concentration time series and persistently high tracer concentrations up to a year after begin of the tracer test indicate multiple porosities
- Elevated nutrients in wells surrounding the septic systems with nitrate concentrations as great as 20 to 60 mg/L
- High tracer concentrations correspond to high nutrient concentrations, wastewater is source of nutrients

- USGS Cedar Key 09/22-24/04

## Acknowledgements

- EPA-Gulf of Mexico Program and DOH-Bureau of Onsite Sewage Programs: funding
- FSU-Dept. of Oceanography: PI Dr. Jeff Chanton and Harmon Harden
- Manatee Springs State Park: Park Manager Sally Lieb
- Suwannee River Water Management District

- USGS Cedar Key 09/22-24/04