Dangers to ground water, wells, and city drinking water supplies

The Curfew product label  expressly prohibits application in soil and water conditions including those found on the Babe Zaharias golf course: “1,3-dichloropropene is known to move through soil and under certain conditions has the potential to reach groundwater as a result of use. Application in areas where soils are permeable and groundwater is near the surface could result in groundwater contamination. Do not apply within 100 feet of any well used for potable water. Do not apply this product within 100 feet from the edge of karst topographical features... Surface features that are associated with karst topography include sinkholes, caverns, springs, and sinking or disappearing streams…Do not apply directly to water, to areas where surface water is present or to intertidal areas below the mean high water mark”

Please read below for documentation from the EPA, US Geological Survey, and other credible professionals about these severe risks to the City of Tampa’s drinking water supply, including the location of nearby sinkholes and private wells; thin groundwater coverage by permeable soil; shallow water tables; and multiple lakes and ponds that receive runoff rain and irrigation water and can be contaminated by airborne transportation of Curfew to adjacent surface water resources.

Click here for the location of sinkholes at several locations adjoining the golf course. Click here for the location of numerous private wells on a partial map of the golf course area (from Appendix B of the 2009 study by Professional Geologist Ronald J. Basso, Jr. prepared for the Southwest Florida Water Management District (SWFMD). Additional research and maps are needed to locate all private wells by the golf course and to determine which of these are within the 100 foot rule for potable wells.

Click here for a detailed 2009 study by Professional Geologist Ronald J. Basso, Jr. prepared for the Southwest Florida Water Management District (SWFMD). This report describes karst geological features of Blue Sink (section 3.0, page 7), located near the golf course’s northeast corner and Lake Eckles (figure 5, page 10). The study focuses on the sink as a source for the City of Tampa’s drinking water supply. The underground water flow was reported from the west-northwest toward the sink area and includes flow from the golf course (figure 12-13, pages 23-24). The report shows thin groundwater coverage by permeable, sandy soil and clay. Figure 3 on page 8 shows the hydrogeologic cross-section of the area. Note that the area to the west where the Babe is located shows shallower sand and clay layers. The area also has shallow water tables and multiple lakes and ponds that receive runoff rain and irrigation water. Given these geological features, it may be surmised that a significant risk to the water supply will occur if Curfew is applied.

From the 2008 Florida Geological Survey and Southwest Florida Water Management District (SWFMD) Bulletin: Hydrogeologic Framework of the Southwest Florida Water Management District  –  (click here for the 92mb file):

  • Soil is highly permeable: Figure 4 (page 9, 23/175) indicates the local geology is: “Med. Fine Sand and Silt”
  • Groundwater is in close proximity to surface: Plate 13 (page 129 of 175) displays geologic cross-section J-J’ through Pinellas and Hillsborough Counties.  Plate 1 (page 117 of 175) shows the location of this cross-section.  The W-16574 long well log is shown on Plate 13 and indicates the depth to the limerock top of the Floridan Aquifer is at an average depth of approx. 45 to 60’ (GS approx. 25-40’ above mean sea level (msl), limestone approx. 20’ below msl.) The aquifer will vary at various locations on the golf course and include significantly shallower levels. Soil borings in various locations across the course can provide more accurate data.

United States Prevention, Pesticides EPA-738-F-98-014 Environmental Protection And Toxic Substances December 1998 Agency (7508C):  “EPA believes the potential for ground water contamination is highest where soils are permeable and water tables are shallowairborne levels of 1,3-D can be transported to adjacent surface water resources.”

Correspondence with Calvin Meyer, US Geological Service: “…the path that groundwater follows is poorly understood in karst areas, and a spill in one area may affect water quality in a completely unexpected location.” Karst geology includes sinks and springs that connect directly with the groundwater supply. The golf course may include these features hidden within ponds and lakes. Click here for a related statement by a Licensed Professional Geologist.