7 Hydrogeology (Posters)

Thursday, 31 March 2016
8:00 AM - 5:30 PM
Exhibit Hall

FORMING A BASELINE WATER QUALITY ASSESSMENT FOR THE GROUNDWATER AND MAIN DRINKING WATER SOURCE OF TYBEE ISLAND, GA

Paper number: 7-8
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Tybee Island, a barrier island approximately 18 miles southeast of Savannah, GA, can see up to a 650% increase in population during summer weekend days; the regular 4,000 inhabitants can grow up to 30,000 people. The purpose of this research is to create a baseline water quality assessment for the City of Tybee that reflects the current water quality of the island’s primary drinking water source (i.e. Upper Floridian Aquifer). Second, the research is to determine if population dynamics on the island, namely residents compared to visitors, influences water consumption. The baseline water quality assessment was conducted during the months of June, July, and August using 8 groundwater monitoring wells dispersed throughout the island. Bi-weekly, the groundwater from these wells was tested for physical and chemical parameters including pH, temperature, nitrates, dissolved oxygen, biological oxygen demand, turbidity and Escherichia coli (E.coli). This results indicated poor turbidity at all well locations (ranging from 19.1 NTU – 657.1 NTU) and fluxes of E. coli (ranging from 0 colonies/mL – 840 colonies/mL). Elevated levels of E.Coli and turbidity were found downgradient of groundwater recharge areas. Measured anion (Cl,SO4, CO3, HCO3) and cation (Mg, Ca, Na, K) constituents follow potentiometric flow lines and reflect similar groundwater chemistries throughout the island. Comparisons of population density maps to water quality and well proximity were inconclusive. However, Likert-scale population surveys (n=294) of both island visitors and residents expressed that the condition of tap water is significantly important; 90% of those surveyed indicated it was very important or important. Overall, the preliminary data helped to determine groundwater flow, point-sources for continual monitoring, and human compassion for continued clean drinking water.

Geological Society of America Abstracts with Programs. Vol. 48, No. 3

doi: 10.1130/abs/2016SE-273483

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