Geophysical Characterization in the Shallow Water Estuarine Lakes of the Southern Everglades, Florida

Michael Eyob Kiflai,Christopher J Madden,René M Price,Thomas A Frankovich,Dean Whitman

doi:10.3390/app12031154

Michael Eyob Kiflai, Christopher J Madden + Show 3 more

Open Access

https://doi.org/10.3390/app12031154

Copy DOI

Abstract

Anthropogenic activities have greatly modified freshwater flows through Everglades National Park (ENP) such that saltwater has intruded extensively inland from the coastline, causing coastal lakes and their ecosystems to be exposed to varying salinity conditions. The Comprehensive Everglades Restoration Plan (CERP) makes an effort to restore the quantity, quality, timing, and distribution of freshwater flow in ENP with a goal of reducing salinity conditions within the coastal communities and adjacent estuaries. An understanding of the temporal and spatial variations of surface water and shallow groundwater salinity in the coastal lakes of ENP is needed to evaluate restoration efforts. Geophysical surveys were conducted between 2016 to 2019 using electrical resistivity and electromagnetic (EM) methods in the coastal lakes of ENP. A mean local formation factor of 10.7 ± 1.8 was calculated for the region by comparing the lakes’ bottom formation inverted electrical resistivity soundings with coincident pore water resistivity measured in groundwater wells. The conductivity of surface and groundwater increased during the dry season, reflecting decreased precipitation, increased evapotranspiration, and the increasing influence of saline water from Florida Bay. Spatially, salinity in the lakes increased from west to east in the surface water with an opposite trend observed in the shallow groundwater. Along the south to north inland direction, the salinity of both surface water and groundwater decreased. This study demonstrates that floating electrical resistivity and EM methods can characterize the subsurface formation resistivity and describe temporal and spatial patterns of surface and shallow groundwater conductivity.

Highlights

Introduction published maps and institutional affilDuring the past century, Everglades National Park (ENP) has been adversely impacted by past human activities that have altered the flow of freshwater through the system [1].the underlying highly permeable limestone aquifer is susceptible to saltwater intrusion (SWI) along the coastline [2]
This paper aims to present the relationship between the freshwater input and hydrochemistry of surface waters and lake-bottom groundwater in shallow (1–2 m) brackish lakes within the southern Everglades known as the Mangrove Lakes (Figure 1)
In the Seven Palm system at monthly intervals during the 2016 dry season, the apparent conductivity measurements increased from February to April (Figure 4)

Summary

Introduction

Introduction published maps and institutional affilDuring the past century, Everglades National Park (ENP) has been adversely impacted by past human activities that have altered the flow of freshwater through the system [1].the underlying highly permeable limestone aquifer is susceptible to saltwater intrusion (SWI) along the coastline [2]. Everglades National Park (ENP) has been adversely impacted by past human activities that have altered the flow of freshwater through the system [1]. In the 1950s, the U.S Army Corps of Engineers developed canals, levees, and water conservation areas for flood protection. Even though this development plan has succeeded in controlling floods, South Florida does not receive sufficient quantity and distribution of water, which results in ecosystem degradation and extensive saltwater intrusion [1]. In 2000, the U.S Congress authorized the Comprehensive Everglades Restoration Plan (CERP) to restore, preserve, and protect the South Florida ecosystem. The CERP makes an effort to restore the quantity, quality, timing, and distribution of freshwater in the region [3]

Objectives

Results

Conclusion