GSA Annual Meeting in Indianapolis, Indiana, USA - 2018

Paper No. 34-13
Presentation Time: 9:00 AM-5:30 PM

ANALYSIS OF TRANSIENT WELL WATER LEVEL RESPONSE TO RAINFALL EVENTS IN MIAMI


VALENCIA, Miguel E., Department of Earth and Environment, Florida International University, 11200 SW 8th Street, AHC-5 360, Miami, FL 33199, ROGERS, Martina, Broward College, DAVIE, FL 33314 and SUKOP, Michael C., Sea Level Solutions Center, Florida International University, University Park, MIAMI, FL 33199

South Florida is subject to repetitive flooding that is a major concern to the population. Transient high water tables caused by rainfall events could be a major factor of flooding in the metropolitan area. Therefore, the scientific community and urban planners acknowledge the need for better understanding of water table variations that can threaten the South Florida population. We performed an analysis of monitoring wells located at Florida International University in central Miami-Dade County, Florida from February 2nd through July 5th 2018. Well C with a depth of ~85.30 ft is completed to fully penetrate the unconfined Biscayne aquifer (primary drinking water source of South Florida) which is characterized by highly transmissive karst limestone. We recorded water table changes using manual measurements along with data-logger data collection (Level TROLL® 700). The data-logger records depth to water, temperature, and pressure every 15 minutes, while the manual data is recorded sporadically. The collected measurements coincide with the transition from dry to rainy season in South Florida. Our focus is to determine the primary drivers that affect the transient fluctuation of the water table. We approached this by correlating the data logger measurements with a water level monitoring station on a nearby canal, and with precipitation from NEXRAD. Our analysis yielded a maximum water table elevation of 2.553 ft, which coincided with the maximum 15-minute precipitation of 0.0516 ft on July 3rd, 2018. This was within 2.913 ft of the ground surface. The water table elevation in Well C fell to 1.142 ft during the dry season. The monitoring station T5W on the C-4 canal located ~ 0.78 miles from the well exhibited a similar water table trends as seen in Well C. The primary drivers influencing the water table in Well C are recharge by rainfall events and C-4 canal levels. Thus, recharge from precipitation (“local” effects) and canal level (“distant” effects) have major influence on Well C. These findings enhance understanding of transient water table behavior in this area, which is a factor in flooding and consequently a major concern of many Floridians.