Florida\u27S Intracoastal Waterway In A Storm Surge Setting: Longwave Physics And Mesh Resolution

This paper works toward the study of the longwave physics and mesh resolution needed for the modeling of storm surge in north Florida; namely, how to incorporate Florida\u27s Intracoastal Waterway, which narrows and becomes highly constricted (only 100 m wide), into a finite element mesh that contains the full coastal domain, including the floodplain. Numerical storm surge experiments are conducted using various domain definitions (finite element meshes) of Florida\u27s Intracoastal Waterway with Hurricane Dora (1964) as the test-case scenario. Questions examined in the paper are: (i) is there a frictional component to Florida\u27s Intracoastal Waterway, that is, does the overall storm surge, as it\u27s propagating over the Intracoastal and into the floodplain, feel any impact because of the Intracoastal\u27s presence; and (ii) how does resolving Florida\u27s Intracoastal Waterway in the finite element mesh affect simulated storm surge conveyance along the Intracoastal, and thus, transmission of storm surge to adjacent water bodies? © 2013 American Society of Civil Engineers

The Influence of Channel Deepening on Tides, River Discharge Effects, and Storm Surge

We combine archival research, semi-analytical models, and numerical simulations to address the following question: how do changes to channel geometry alter tidal properties and flood dynamics in a hyposynchronous, strongly frictional estuary with a landward decay in tidal amplitudes? Records in the Saint Johns River Estuary since the 1890s show that tidal range has doubled in Jacksonville, Florida. Near the estuary inlet, tidal discharge approximately doubled but tidal amplitudes increased only ~6%. Modeling shows that increased shipping channel depths from 5-6 to ~13m drove the observed changes, with other factors like channel shortening and width reduction producing comparatively minor effects. Tidal amplitude increases are spatially variable, with a maximum change 20-25 km from the estuary inlet; tidal theory suggests that increases in amplitude approximately follow , where x is the distance from the ocean and is a damping coefficient. Tidal changes are a predictor of altered surge dynamics: Numerical modeling of hurricane Irma under 1898 and 2017 bathymetric conditions confirms that both tidal and storm surge amplitudes are larger today, with a similar spatial pattern. Nonetheless, peak water levels are simulated to be larger under 1898 bathymetry. The cause is likely the record river discharge observed during the storm; as suggested by a subtidal water-level model, channel deepening since 1898 appears to have reduced the average surface slope required to drain both mean river flow and storm flows towards the ocean. Nonetheless, results suggest an increased vulnerability to storms with less river flow, but larger storm surge