Royer, E.L. and Wang, P., 2024. Mitigating anthropogenic influences on tidal circulation: A case study at McKay Bay, Florida, USA. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 148-153. Charlotte (North Carolina), ISSN 0749-0208.
McKay Bay is a heavily altered 3.5 km2 shallow sub-estuary at the northeastern end of Tampa Bay. The circulation within McKay Bay is mainly driven by tides from the Gulf of Mexico. Typical of many estuaries, a bridge and causeway were built crossing the mouth of the bay in addition to numerous dredge and fill projects within the bay substantially altering the bathymetry and circulation pattern. This heavily engineered system provides an opportunity to understand how historical management decisions and practices can influence the current and future health of the bay and to explore nature-based solutions to mitigate negative effects. A numerical flow model was built using the US Army Corps of Engineer's Coastal Modeling Systems (CMS). The model was calibrated and verified using measured current velocities throughout the bay. Under present conditions, tidal flow is concentrated in the dredged channel through the middle of the bay while low flow zones occur along the shoreline, negatively impacting nearshore habitat. These nearshore “dead zones” were not computed over the natural conditions before anthropogenic modifications. Flow patterns under different bathymetry alterations were simulated with the goal of improving nearshore circulation. The modeling results were used to evaluate various nature-based solutions to mitigate negative impacts from past engineering activities. The best results were achieved by filling the channel in the middle of the bay along with an elongated shoal and spur, mimicking the removed bay-head delta. This approach is applicable to other shallow estuaries.
