The Examination of Extreme Flood Events and Resiliency in the Middle St. Johns River, Florida USA Via Multiple Methods

The middle portion of the St. Johns River is located in East-Central Florida, USA. This region of the St. Johns River is increasingly subject to urbanization and conversion of forest areas to agricultural land. Overall, these changes mean that future flood events in the area could adversely impact local citizens. Therefore, the examination of extreme flood events and resiliency to such events is critically important. The purpose of this preliminary study is to explore a range of practical applications to estimate extreme flood events at locations within the Middle St. Johns River Basin, focusing specifically upon the Wekiva River sub-basin (located just west of Lake Mary, Florida). The current work illustrates the overall technical methodology and provides preliminary estimates of extreme flood events at different return frequencies using two statistical approaches. Future work will also estimate the magnitude of extreme flood events via model simulations utilizing an existing Wekiva River HSPF rainfall-runoff model previously developed by the Saint Johns River Water Management District. Altogether, once fully integrated and complete, the methods will permit prediction of a range of possible flood discharges at any place along the Wekiva watercourse.