Water Well Journal

April 2016

Water Well Journal

Issue link: https://read.dmtmag.com/i/655200

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Page 19 of 67

wells flow with 20 pounds of pressure or more, creating quite a gusher. He says anticipating this while addressing it when drilling is necessary along with selecting the right pump size to accommodate the varying water levels in certain parts of Florida. Depending on the pressure after punching into the aquifer, Partridge says the quality of the mud drilling program comes into play if the ground formation begins free flowing. Depending on the flow, the well may need to be staged down and telescoped. "If we want to drill a 2-inch well, we may have to do 8 inches at the surface, install 4-inch casing, and reduce it to 2," Partridge says. "Therefore, if we run into problems we can backtrack or be safe above that zone because we've got grouted casing in place. "Knowing how much flow, how it will affect drilling, and where the water is going to go is important. It's not uncom- mon for us to get artesian wells in this area. Some of the factors we consider are elevation, location, and well logs to anticipate the flow rate." Caverns and sinkholes are also issues to be watchful for in central and west central Florida, where limestone is shallow (80 feet) and has karst features. The topography creates an environment where water rushes underground, eroding the sand—causing sinkholes. According to Partridge, there are incidents of washouts but no true sinkholes in northeast Florida due to the limestone of the Upper Floridan aquifer being so deep, providing sufficient aquifer protection. Water Quality In parts of Florida, a misnomer is the deeper you go the better water quality you'll find. Partridge hears customers say this, yet it's often not the case. Instead, Partridge explains the deeper you go the more salinity and more chlorides you'll find. "In certain parts of the state, especially toward the coast- lines, the deeper you go the greater risk of getting saltwater in your well from saltwater intrusion," he says, "so generally some areas you just want to scratch the surface of the Floridan aquifer system in order to avoid getting to that deeper depth where chlorides may be present." Water quality and water treatment, the issue focus of this month's Water Well Journal, is a major part of Partridge Well Drilling, which installs water treatment systems. They have customers who believe wells in northeast Florida have the staining mineral iron and sulfur. Again, Partridge says more often than not iron is not present. Typically, the Upper Flori- dan aquifer can have a high presence of sulfur but it can be easily treated. "We guarantee our customers not to have iron staining present in their water," he says, "which is a big advantage for us and a good thing to be able to promise our customers because they're concerned about that. "The shallower wells typically do have iron, but we can drill customers a well in the Upper Floridan aquifer and get them good, quality water. The city water in our area is drawn from Upper Floridan aquifer wells, so they're comforted with the idea their water will be of similar quality." Iron can sometimes be present in rock, gravel pack, and shallow wells. Partridge Well Drilling does not recommend treating irrigation water for iron. But if iron staining is a con- cern, the company recommends drilling an Upper Floridan aquifer or intermediate well (3- or 4-inch-diameter well at 220-320 feet). The U.S. Geological Survey and U.S. Department of the Interior found the quality of groundwater in the Upper Flori- dan aquifer to be among the nation's best, according to their circular paper, Water Quality in the Upper Floridan Aquifer and Overlying Surficial Aquifers, Southeastern United States, 1993–2010. Fewer than 1 in 20 water samples collected from drinking- water wells in the Upper Floridan aquifer contained a con- stituent at a concentration that exceed a human-health benchmark. Radon exceeded its human-health benchmark most frequently. Water Well Permitting All wells in Florida require a permit from one of the state's five water management districts. Each district has a different way of permitting certain diameter wells. Partridge Well Drilling, located in the northeastern part of the state, operates in the St. Johns River Water Management District. Over the last few years the Florida Department of Environ- mental Protection (DEP) has focused on increasing efficiency and statewide consistency of water-related permitting in Florida. The focus is on the Consumptive or Water Use Permitting (CUP/WUP) program and the Environmental Re- source Permitting program. The Consumptive Use Permitting Consistency Initiative—commonly known as "CUPcon"— addresses the CUP/WUP program, where a 2012 state law began efforts to make the Environmental Resource Permitting program more consistent. The DEP, along with the five water management districts, which are responsible for implementing the CUP/WUP AQUIFERS from page 17 Image courtesy St. Johns River Water Management District. waterwelljournal.com 18 April 2016 WWJ

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