###### Abstract
Integrated approaches of electromagnetics (EM) and direct current resistivity were applied in the coastal wetland of Tampa Bay, Florida [10] and Azan Basin, Jordan [11]. [PERSON] et al. [12] used EM 31 for rapid characterization of shallow water, the contaminated wetlands of Kearny Marsh, New Jersey. EM methods have been used for imaging saltwater intrusion in coastal aquifers--namely the seaside groundwater basin, California [13]--and for characterizing the chemical properties of soil in Sidorlandia, MS, Brazil [14]. Electrical resistivity has an advantage because the non-uniqueness of the resistivity method is less compared with other geophysical methods such as electromagnetic methods [15]. The electrical resistivity method is superior for imaging the electrical resistivity structure compared to other non-invasive geophysical imaging techniques. DC resistivity offers several advantages over EM methods because the array is in direct galvanic contact with the water or earth and is not affected by external magnetic fields and nearby conducting bodies such as the boat and operator. The EM method provides a faster alternative to DC soundings [16], but it is sensitive to electromagnetic noise produced by metals, pipelines, etc. Therefore, the DC resistivity sounding remains the preferred method, though an integrated approach using both methods is complementary. The integrated approaches of EM, electrical resistivity, and well data are the most effective technique to estimate a formation factor, which is used to produce a regional map of groundwater salinity. A formation factor is the ratio of the resistivity (conductivity) of a rock filled with water to the resistivity (conductivity) of that water. It can be determined by coincident measurements of groundwater and formation conductivity or from empirical relationships such as Archie's Law [17]. An effective technique to map pore water conductivities is to compute a formation factor from resistivity surveys and pore water samples. An integrated approach of EM and electrical resistivity was conducted on the wetland of Tampa Bay, Florida [10] and computes a formation factor from resistivity surveys and pore water samples. The study conducted by [18] estimated a formation factor of 5.1 by comparing EM induction logs and water samples from wells in eastern Miami-Dade County. Similarly, in other studies, [PERSON]. [19] estimated a formation factor of 9.65 in Everglades National Park using similar methods and [20] estimated a formation factor of 9.8 for Big Pine Key using ERT and water samples from wells. The formation factor depends on several parameters such as porosity, the degree of saturation, cementation, and pore fluid resistivity and heterogeneity. Figure 1: Map of South Florida showing the location of Everglades National Park (ENP), Everglades Agricultural Areas (EEA), Water Conservation Area (WCA), Shark River Slough (SRS), Taylor Slough (TS), Meteorological NCL station (Red Pin), well stations, and geophysical survey. The SRS flows from the north to the southwest into the Gulf of Mexico, and the TS flows south into Florida Bay. The geophysical survey includes EM survey denoted by lines and floating array electrical resistivity denoted by letters from a to r. Map coordinates are in UTM, Zone 17N. A number of geophysical studies have been conducted in the ENP. A study conducted in the southern ENP [19] aimed to assess saltwater intrusion and prepared a subsurface resistivity map using airborne electromagnetic methods (FDEM) and borehole geophysical measurements. The authors established correlations between formation resistivity and water-specific conductance for the region and provided a baseline for further studies. In 2011, a TDEM survey was conducted in Miami-Dade County and delineated the location of the freshwater/saltwater interface, as well as showing the influence of canals and roadbeds on the hydrologic regime [19; 21].