Owners may undertake hydrogeological studies for a variety of reasons, but most often these studies are conducted in support of an anticipated permit application that requires background data or is conducted in response to concerns raised by regulators. Such studies often require the installation of monitor wells and piezometers, staff gauges and water recording devices; the collection and analysis of water samples; and groundwater and surface water modeling. The following are studies we have completed.
Plum Creek Spring Study
Searched for unknown springs on 250,000 acre tract in west-central Florida for potential spring water bottling operation. Methods of investigation included geothermal imaging, fracture trace analysis, air photography, and ground thruthing. Three largest springs were gauged multiple times to determine range in discharge and were sampled in triplicate multiple times to assess water quality over time and seasons. Springs were also inspected during rainy season to determine effects of tannic acid-rick runoff on spring and spring run water clarity. Plans for permitting are on hold.
Residential Development Groundwater Availability Study
Cedar Key, Florida
Evaluated viability of using groundwater for potable water supply for residential subdivision along salt marsh and immediately east of Cedar Key and Golf of Mexico after owner had been advised only alternative was prohibitively expensive desalinization. Test wells discovered lens of fresh groundwater above salty groundwater. Modeling demonstrated that withdrawals from a single large well would produce significant upwelling of salty water that would ruin the waste supply in short order, but that individual shallow wells at each home site could sustainable provide fresh groundwater for the development. Project was completed using shallow wells at each home site.
Limestone Quarry Salt Water Intrusion Analysis
Slightly elevated chloride levels in quarry water prompted FDEP to order owner to determine if mining in this coastal setting was causing deep, salty groundwater to up-cone beneath the property, placing nearby potable water wells at risk. FDEP believed that the freshwater/saltwater interface was very shallow because of the proximity of the quarry to the coast, and that the 80-foot-deep mining activity was breaching this interface. To investigate, deep core holes (500 feet or more) were advanced and groundwater samples were collected at discrete intervals which proved that the base of the upper Floridan aquifer was at 500 feel (well below the base of mining). Approximately 90 monitor wells were installed along transects perpendicular the Gulf shoreline and to the Cross-Florida Barge Canal, including shallow and deep well pairs. Water quality and water level data (recorded with electronic data loggers) proved the chlorides were introduced to the quarry by storm surge and not through saltwater intrusion or up-coning. Groundwater modeling proved expansion of the mine would not significantly increase chloride levels in the quarry and that area wells would not be affected.