Investigation of Submarine Springs and other Karst Features in Coastal Regions of the SWFWMD

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1 Investigation of Submarine Springs and other Karst Features in Coastal Regions of the SWFWMD by David J. DeWitt, P.G. Southwest Florida Water Management District January 2004 FDEP Q- Meeting Clearwater Florida

2 PURPOSE Address persistent suggestions that an untapped potential water supply source may exist along the coastal margins of the District by identifying and locating possible offshore submarine springs. OBJECTIVES - Locate submarine springs in the Gulf coastal margin of the SWFWMD. - Characterize spring locations, ie. distance offshore, water depth, etc. - Describe spring vent geometry and flow characteristics relative to water depth, tidal stage, visible boil or flow at surface etc. - Collect water quality data from spring vents through tidal cycles.

3 Crescent Beach Spring Crystal Beach Spring SWFWMD Study Area from Kincaid, T.R. 1999, Morphologic and Fractal Characterization of Saturated Karstic Caves. Ph.D. Dissertation, University of Wyoming

4 Miles N

5 Radon concentrations from Gulf of Mexico water samples (Fanning, K., L. Torres, and J.A. Breland, II Ra-226 and Rn-222 along Florida s coasts, In Symposium on Natural Radiation and Technologically Enhanced Natural Radiation in Florida, pp , Florida Chap. Health Physics Society)

6 Upper Floridan Aquifer Potentiometric Surface 0 predevelopment surface 10 May 1998 surface GULF OF MEXICO

7 METHODS - Compile existing information on submarine springs - Conduct inquiries with other government agencies, local SCUBA divers and offshore fishing charters to identify unpublished spring locations - Analysis of GIS aerial photos to locate existing offshore springs and identify similar photographic features for possible spring locations. - Field reconnaissance and data collection at offshore spring sites.

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10 Tampa Bay Spot < >

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13 St. Petersburg Marina

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15 Postcard illustration of the historical St. Petersburg waterfront showing the piers in Tampa Bay with bathhouses supplied by artesian wells.

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17 CRYSTAL BEACH SPRING 1000 ft.

18 SWFWMD GIS 1999

19 Low altitude aerial photo of the Crystal Beach submarine spring (from Surface boil, Crystal Beach Spring photo taken in December of 2001.

20 from Divers Explore Cave s Secrets, by Edie Gross St. Petersburg Times, published May 3, 1998 from M. Garman, Karst Ecosystem Spotlight: Crystal Beach Springs, Florida, National Speleological Society North American Biospeleology Newsletter, No. 47, March 1999.

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25 SPRING VENTS

26 Sept. 17, 2003 Discharge Measurement Data from Crystal Beach Spring measurement grid (top) and the contoured velocity data (bottom) resulting in a reported net instantaneous discharge of cfs or 14.7 mgd.

27 1999 aerial orthophoto of the Howard Park spring offshore of Tarpon Springs, northern Pinellas County

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29 Cave map diagram of the Howard Park submarine spring, by Mike Emanuel (source,

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32 N Feet ( from )

33 Nov- 2001: WATER QUALITY PROFILE, UNNAMED SPRING No. 4, PASCO COUNTY D.O. ph DEPTH (ft) SP COND (ms/cm) TEMP deg-c

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35 Miles Cedar Island Spring HUDSON N

36 Close up aerial images of Cedar Island Spring offshore of Hudson, Pasco County Miles N

37 Nov- 2001: WATER QUALITY PROFILE, CEDAR ISLAND SPRING-EAST, PASCO COUNTY DEPTH (ft) DEPTH (ft) TEMP deg-c ph COND us/cm D.O. mg/l ~ 25 feet tagged depth SP COND (x 1000)

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39 Close up view of the Jewfish Hole offshore spring offshore of Aripeka, Pasco County Feet N

40 0 April-2002: WATER QUALITY PROFILE, THE JEWFISH HOLE, PASCO COUNTY DEPTH (ft) TEMP ph COND D.O SP COND (x 1000) TEMP deg-c

41 Hernando County possible spring/sink karst features Pine Island Beach N Miles

42 Miles N Apparent karst features north of Pine Island, offshore Hernando County

43 CITRUS CO. HERNANDO CO.

44 N 1 MILE St. Martins River St. Martins Keys Little Homosassa River Maya Spring

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47 St Martins- Maya Spring < visual inspection of vent Water-quality profiling with YSI datasonde >

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51 Large Submarine Sink Features in the Gulf of Mexico Offshore of the SWFWMD

52 Upper Floridan Aquifer Potentiometric Surface 0 predevelopment surface 10 May 1998 surface

53 Schematic profile of the "Big Freshwater Spring" located offshore of Pinellas County. (unpublished sketch by William L. Wilson, based on a dive performed on July 27, 1991.)

54 Profile diagram of the Amberjack Hole, located in the Gulf of Mexico 32 miles offshore of Sarasota (by Curt Bowen, 1993).

55 Profile of Green Banana Sink, located in the Gulf of Mexico 50 miles offshore of Sarasota (from Underwater Speleology, Volume 21, Number 5, September/October 1994)

56 THINGS LEFT TO DO - Publish report on preliminary data and results - Conduct discharge measurements at flowing sites - Additional water-quality profiling and data collection - Continue search for additional potential sites - Work with other researchers on remote sensing techniques