GSA Connects 2021 in Portland, Oregon

Paper No. 59-12
Presentation Time: 2:30 PM-6:30 PM


DAVIS, Lane, ROTZ, Rachel, THOMAS, Serge, MOREJON, Jasmine, THOMAS, Daniel, LOPEZ, Janelys and PIQUIET, Megan, Department of Marine and Earth Sciences, Florida Gulf Coast University, 10501 FGCU Blvd S, Fort Myers, FL 33965

The master-planned community of Bonita Bay in Southwest Florida was harmoniously integrated into the natural landscape including the protected Imperial River and Spring Creek drainage systems which feed Estero Bay and the Gulf of Mexico. The community contains more than 3,100 homes, 56 neighborhoods, as well as several golf courses, preserves, and parks. Recent environmental concerns including harmful algal blooms, diminishing sea grass, oyster population decline, and high amounts of red tide in Estero Bay have raised concerns by the Bonita Bay Community on its contribution of pollutants to the region. This study focused on the groundwater quality of the Bonita Bay community and was part of a larger, extensive investigation to determine the efficacy of the imposed drainage system and the effect of fertilizers, bacteria, and reclaimed wastewater on the surface and subsurface waters of Estero Bay. Ten temporary groundwater wells were installed with push point piezometers (inside diameter = ⅞”) to sample groundwater in the field and analyze in the laboratory. Parameters included nutrients (i.e., total phosphorus, total nitrogen, nitrate, nitrite, ammonia), copper, bacterial DNA, 13C and 18O isotopes, and sucralose. In addition, a water table elevation and flow direction map was created using ESRI’s ArcMap, as well as groundwater flow velocities for the shallow groundwater (< 12 ft) in the unconfined aquifer beneath the community. Preliminary results demonstrate that total nitrogen concentrations were two times higher on average in groundwater than surface water (2.95 mg/L, 1.41 mg/L) and exceed the impairment criterion (TN = 0.63 mg/L) for healthy seagrass growth. This study was initiated and supported by the Bonita Bay Community Association as a way for the academic and residential communities to collaborate on environmental problems in the area. Understanding the impact of master-planned communities on the surface and subsurface waters is important particularly in highly-populated, subtropical, coastal regions where the use of nutrients on domestic, recreational, and agricultural land significantly impacts human health, the environment, wildlife, and economy of the area.